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Review of Human Hand Microbiome Research

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Review of Human Hand Microbiome Research

Abstract and Figures

Recent advances have increased our understanding of the human microbiome, including the skin microbiome. Despite the importance of the hands as a vector for infection transmission, there have been no comprehensive reviews of recent advances in hand microbiome research or overviews of the factors that influence the composition of the hand microbiome. A comprehensive and systematic database search was conducted for skin microbiome-related articles published from January 1, 2008 to April 1, 2015. Only primary research articles that used culture-independent, whole community analysis methods to study the healthy hand skin microbiome were included. Eighteen articles were identified containing hand microbiome data. Most focused on bacteria, with relatively little reported on fungi, viruses, and protozoa. Bacteria from four phyla were found across all studies of the hand microbiome (most to least relative abundance): Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes. Key factors that impacted the hand microbiome composition included temporal and biogeographical dynamics, as well as intrinsic (age, gender) and extrinsic (product use, cohabitants, pet-ownership) variables. There was more temporal variability in the composition of the hand microbiome than in other body sites, making identification of the “normal” microbiome of the hands challenging. The microbiome of the hands is in constant flux as the hands are a critical vector for transmitting microorganisms between people, pets, inanimate objects and our environments. Future studies need to resolve methodological influences on results, and further investigate factors which alter the hand microbiome including the impact of products applied to hands. Increased understanding of the hand microbiome and the skin microbiome in general, will open the door to product development for disease prevention and treatment, and may lead to other applications, including novel diagnostic and forensic approaches.
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Review article
Review of human hand microbiome research
Sarah L. Edmonds-Wilson
a,
*, Nilufar I. Nurinova
b
, Carrie A. Zapka
a
,
Noah Fierer
c
, Michael Wilson
d
a
Research and Development, GOJO Industries, United States
b
Department of Biostatistics and Epidemiology, Kent State University, United States
c
Department of Ecology and Evolutionary Biology, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, United States
d
University College London, United Kingdom
Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Overview of hand microbiome studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Microbiome of the hands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.3. Metabolic functions of the hand microbiome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4. Temporal dynamics of the hand microbiome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.5. Biogeographical dynamics of the hands compared to other body sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Journal of Dermatological Science 80 (2015) 3–12
ARTICLE INFO
Article history:
Received 22 June 2015
Received in revised form 13 July 2015
Accepted 16 July 2015
[2_TD$DIFF]Keywords:
Microbiome
Hand hygiene
Hand
Skin
Metabolome
ABSTRACT
Recent advances have increased our understanding of the human microbiome, including the skin
microbiome. Despite the importance of the hands as a vector for infection transmission, there have been
no comprehensive reviews of recent advances in hand microbiome research or overviews of the factors
that influence the composition of the hand microbiome.
A comprehensive and systematic database search was conduct ed for skin microbiome-related articles
published from January 1, 2008 to April 1, 2015. Only primary research articles that used culture-
independent, whole community analysis methods to study the healthy hand skin microbiome were
included.
Eighteen articles were identified containing hand microbiome data. Most focused on bacteria, with
relatively little reported on fungi, viruses, and protozoa. Bacteria from four phyla were found across all
studies of the hand microbiome (most to least relative abundance): Firmicutes, Actinobacteria,
Proteobacteria, Bacteroidetes. Key factors that impacted the hand microbiome composition included
temporal and biogeographical dynamics, as well as intrinsic (age, gender) and extrinsic (product use,
cohabitants, pet-ownership) variables.
There was more temporal variability in the composition of the hand microbiome than in other
body sites, making identification of the ‘‘normal’’ microbiome of the hands challenging. The
microbiome of the hands is in constant flux as the hands are a critical vector for transmitting
microorganisms between people, pets, inanimate objects and our environments. Future studies need
to resolve methodological influences on results, and further investigate factors which alter the hand
microbiome including the impact of products applied to hands. Increased understanding of the hand
microbiome and the skin microbiome in general, will open the door to product development for
disease prevention and treatment, and may lead to other applications, including novel diagnostic and
forensic approaches.
ß2015 The Authors. Published by Elsevier Ireland Ltd. on behalf of Japanese Society for Investigative
Dermatology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/
licenses/by-nc-nd/4.0/).
*Corresponding author at: PO Box 991, Akron, OH 44309, United States.
E-mail address: wilsonsa@gojo.com (S.L. Edmonds-Wilson).
Contents lists available at ScienceDirect
Journal of Dermatological Science
journal homepage: www.jdsjournal.com
http://dx.doi.org/10.1016/j.jdermsci.2015.07.006
0923-1811/ß2015 The Authors. Published by Elsevier Ireland Ltd. on behalf of Japanese Society for Investigative Dermatology. This is an open access article under the CC BY-
NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
3.6. Intrinsic factors impacting hand microbiome composition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.7. Extrinsic factors impacting hand microbiome composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
Human skin is the first layer of defense against infectious
microorganisms and toxic agents. Skin is the largest human organ,
and is a dynamic environment; constantly impacted by internal
factors and exposed to external conditions. These intrinsic and
extrinsic factors can alter the microbial community on the skin
[1]. Until recently, skin microbiology was limited to culture-
dependent studies, with mostsamples from pathologies [2].Howev-
er, non-pathological bacteria are detected everywhere on humans,
with up to 1 10
7
bacteria per cm
2
on the skin [3]. Although the
culture-based approach is still common, many microorganisms are
difficult to cultivate and are therefore under-represented or
undetected in culture-based surveys. The availability of cost-
effective and high-throughput culture-independent methods, in-
cluding 16SrRNA gene sequencingand advanced bioinformatics, has
significantly improvedour understanding of thehuman microbiome
[4,5]. An advantage of targeting the 16S rRNA gene is that it is
universalin bacteria, and allows sequences between organismsto be
compared at various levels of taxonomic resolution in contrast to
culture-based classification which is limited to morphological and
phenotypical classification [6]. Other approaches, including meta-
genomics are used to capture the full range of diversity in the
microbiome,including fungi, viruses and protozoa [7].Todatemany
studies of the human microbiome have focused on the gut and oral
microbiomes. There are increasing numbers of skin microbiome
studies,however, samplinghas rarely focusedon the hands [8,9].Our
knowledgeof the hand microbiomeand factors that impact it arestill
primarily limited to culture-based studies.
Human hands are a conduit for exchanging microorganisms
between the environment and the body. Hands can harbor
pathogenic species, including [3_TD$DIFF]methicillin-resistant Staphylococcus
aureus[4_TD$DIFF] (MRSA) or Escherichia coli; particularly within high risk
environments, such as healthcare and food-handling settings
[10]. Product use can impact the hand microbiome, with greater
pathogen hand carriage on people using a high level of hand
hygiene products, while other studies have demonstrated reduced
pathogen carriage and/or infections with use of these products.
Frequently washed hands of healthcare workers are colonized with
more pathogenic bacteria than those who wash less frequently
[11]. Hand washing with soap dispensed from open bulk-refillable
dispensers was shown to increase the levels of opportunistic
pathogens on childrens’ hands in an elementary school [12]. How-
ever, many studies have demonstrated the beneficial impact of
hand washing and/or use of alcohol-based hand rubs for reducing
pathogenic bacteria on hands and/or reducing infection rates in
various institutional settings [13–15]. The occurrence of pathogens
on hands is well-studied; in contrast, hands are rarely considered a
source of beneficial bacteria contributing to our healthy micro-
biome.
Since hands are important for intrapersonal and interpersonal
transfer of microorganisms, as well as environmental transfer, the
dynamics of hand microbial communities and factors impacting
them are of considerable importance [16]. Key topics include
understanding the normal microbiome of healthy hands, how
microbes are transferred by hands, what factors impact the hand
microbiome, and whether those impacts are beneficial or
detrimental to human health. This is the first review of hand
microbiome studies. Most microbiome studies have focused on
detecting bacteria, fewer have determined what fungi, viruses or
protozoa were present. Therefore, this review is focused on the
hand-associated bacterial communities, but will mention other
organisms where data are available. Additionally, the authors will
highlight the importance of hands as a critical vector in
microbiome dynamics.
2. Methods
The database search was performed using PubMed, ABI/
INFORM Professional, BIOSIS Previews, British Library Inside
Conferences, Current Contents Search, Embase, Embase Alert,
Gale Group Health Periodicals Database and PharmaBioMed
Business Journals, Global Health, International Pharmaceutical
Abstracts, Lancet Titles, Medline, The New England Journal of
Medicine, PASCAL, and SciSearch
1
. Search terms were: hand and/
or skin microbiome, skin metabolome, hypothenar palm micro-
biome, epidermal microbiome, cutaneous microbiome, stratum
corneum bacteria.
Fig. 1 shows a schematic of article selection criteria. The search
resulted in >600 peer-reviewed articles published from 1/1/2008
through 4/1/2015. Articles were selected for review based on the
requirement for culture-independent and whole community analy-
sis methods to characterize the human skin microbiome. Articles in
the review were further refined by including only primary research
articles that studied the healthy hand microbiome.
3. Results
3.1. Overview of hand microbiome studies
Table 1 summarizes the 18 articles that met all search criteria,
and provides an overview of methods for each study. Samples for
microbial analyses were typically collected by swabbing the hand
[(Fig._1)TD$FIG]
Fig. 1. Schematic of process for selection of articles.
S.L. Edmonds-Wilson et al./ Journal of Dermatological Science 80 (2015) 3–12
4
Table 1
Summary of study methods for articles assessing the hand skin microbiome..
Reference Skin sampling
method
Setting Subjects’ age,
gender, and
ethnicity
N# Repeat
samples
Sampling
duration
Area of hand(s)
sampled
Non-hand
site(s) sampled
16S rRNA gene
survey
amplification
region(s)
Other microbiome
characterization
method(s) or
metadata
Bouslimani
et al. [21]
Swab University of
California, San
Diego
Healthy
subjects, a male
and a female
2 2 Not specified Front and back 400 other skin
sites
V3–V5 UPLC-QTOF MS,
MALDI-TOF, 3D
Modeling
Caporaso
et al. [22]
Swab Boulder, CO Healthy
subjects, a male
and a female
2>396 Daily; Male for
15 months,
female for
6 months
Palms Stool, oral V2, V4–V5 N/A
Costello
et al. [24]
Swab Boulder, CO Healthy adults
of both sexes,
ages 30–60
9 4 2 consecutive
days, 2,
3 months apart
Palms and index
fingers
Hair, nose, ear,
oral, stool
V1–V2 N/A
Fierer
et al. [17]
Swab Boulder, CO Healthy
students of
mixed gender
51 1 N/A Palm N/A V1–V2 N/A
8 3 Handwash
Pilot: every 2 h
for 6 h
Fierer
et al. [33]
Swab Boulder, CO Healthy adults
of mixed
gender, ages
20–35
Key-board: 3 1 N/A Fingertips (ventral
surface of distal
joint)
Armpit,
keyboard keys,
computer
mouse
V1–V2 N/A
Mouse: 9 1 N/A Palms
Findley
et al. [19]
Swab and skin
scraping
Washington DC
Area
Healthy adults
ages 18–40
18 1–2 Subset of
subjects
sampled 1–3
months post
initial sample
Left and right
hypothenar palm
13 other skin
sites
V1–V3 18S rRNA and ITS1
amplicon
sequencing
Flores
et al. [23]
Swab University of
Colorado Boulder,
Northern Arizona
University, North
Carolina State
University
College students 85 >10 Weekly for
10 week
minimum
Palms Forehead, oral,
stool
V4–V5 Weekly survey of
demographic,
lifestyle and health
information
Grice
et al. [25]
Swab and skin
scraping
Washington DC
area
20–41 y/o 10 2 4–6 month after
initial sampling
Hypothenar palm
and interdigital
web space, both
hands
18 other skin
sites
V1–V9 N/A
Hospodsky
et al. [32]
Glove juice U.S. and Tanzania Adult females 44 1 N/A Whole hands N/A V3–V5 N/A
Lax et al. [16] Swab Houses in Illinois,
Washington and
California
Unknown 15 adults,
3 children
>20 Every other day
for 6 weeks
Unknown Nose, home
surfaces, pets
V4–V5 Shotgun
sequencing
Mathieu
et al. [2]
Swab Unknown Caucasian
males, ages 25–
26
2 Every
two days
One week Palm Face, axilla, feet,
and retro
auricular crease
Unknown Functional
classification of
genes based on
reference
metagenomic
databases
Meadow
et al. [30]
Swab Princeton, NJ Adults 17 1 time
point
N/A Thumb and index
finger
Cell phone V4–V5 N/A
Nakatsuji
et al. [28]
Surgical biopsy San Diego, CA 2 males and
1 female ages
53–69
11 1 N/A Palm (cut from the
dermis to the
epidermis)
Face V6–V7, gene-
specific primers
Immunostaining,
laser capture
microdissection
S.L. Edmonds-Wilson et al. / Journal of Dermatological Science 80 (2015) 3–12
5
Table 1 (Continued )
Reference Skin sampling
method
Setting Subjects’ age,
gender, and
ethnicity
N# Repeat
samples
Sampling
duration
Area of hand(s)
sampled
Non-hand
site(s) sampled
16S rRNA gene
survey
amplification
region(s)
Other microbiome
characterization
method(s) or
metadata
Oh et al. [20] Swab/scrape/
swab technique
Washington DC 9 males and
6 females, ages
23–39
15 1 N/A Hypothenar palm
and interdigital
web space
16 other skin
sites
V1–V3 de novo
identification,
reference base
strain mapping
Rosenthal et al.
[18]
(Pathogens)
Swab and glove
juice
University of
Michigan Hospital
SICU
Healthcare
workers, mostly
female,
caucasian, born
in US, ages 20–
59
34 3 Weekly for
3 weeks
Palm, fingertips,
and in-between
fingers
N/A V6 18S rRNA gene
survey; participant
survey and visual
hand skin
assessment
Rosenthal et al.
[26] (PLOS
ONE)
Swab and glove
juice
University of
Michigan Hospital
SICU
Healthcare
workers, mostly
female,
caucasian, born
in US, ages 20–
59
34 3 Weekly for
3 weeks
Palm, fingertips,
and in-between
fingers
N/A V6 N/A
Smeekens et al.
[1_TD$DIFF][31]
Swab Netherlands Healthy
controls;
chronic muco-
cutaneous
candidiasis and
hyper-IgE
syndrome
patients
11 case;
10 control
1 N/A Unknown Feet, trunk and
oral
V4–V5 Immunological in
vitro stimulations
assays to identify
genetic potential
defects
Song et al. [29] Swab Households Couples, age
26–87, and
children
(6 months–18
years)
159 1 N/A Palms Forehead, oral,
stool, dogs
V2 N/A
S.L. Edmonds-Wilson et al./ Journal of Dermatological Science 80 (2015) 3–12
6
surface. For studies that utilized 16S rRNA gene sequencing,
investigators used a variety of gene regions for sequencing. Overall,
the data on hands is limited compared to other body sites, and the
majority of studies were conducted on young adults, often
students or professionals, in the United States. Most studies
contained a small sample size (10) and/or assessed microbial
composition at a single time-point.
3.2. Microbiome of the hands
Eleven studies in this review characterized the relative
abundance of bacteria on hands, and findings are summarized
in Table 2.Table 2 displays bacteria families found at 1% or greater
relative abundance. Most studies reported between 8 and 24 fami-
lies of bacteria on hands. Bacteria were found from four phyla
across all studies (most to least relative abundance): Firmicutes,
Actinobacteria, Proteobacteria, and Bacteroidetes. There were
considerable differences in the types of bacteria found among
the studies, with Staphylococcaceae, Corynebacteriaceae, Propio-
nibacteriaceae and Streptococcaceae being found in a majority of
the studies. Interestingly, Propionibacteriaceae, when detected,
was often quite high in relative abundance.
The first study of the hand microbiome demonstrated there are
on average >150 bacterial species found on the palms, with 3 phyla
accounting for >94% of sequences: Actinobacteria, Firmicutes and
Proteobacteria [17]. A study evaluating the hands of healthcare
workers found those with less microbial diversity were more likely
to harbor pathogenic microorganisms on the hands, such as S.
aureus (including MRSA), Enterococcus spp., or Candida albicans
[18]. One study evaluated both fungal and bacterial diversity on
the hands and found Malassezia spp. were the most common fungal
inhabitants, with Aspergillus spp. the second most common
[19]. Bacteria were the most prevalent microorganism (>80%
relative abundance), then viruses, and fungi being least prevalent
(<5% relative abundance) on hands [20]. However this finding may
be somewhat biased for greater proportion of bacteria, since the
relative size of viral genomes is small, and would therefore be
expected to represent proportionally less of the sequence data,
even if bacteria and viruses were equally abundant.
3.3. Metabolic functions of the hand microbiome
Three studies reviewed used culture-independent metabolomic
techniques to investigate the functional (metabolic) role of the skin
microbiome, including hands. Mathieu et al. [2] evaluated the
functional characteristics of the hand microbiome, however
samples were pooled from multiple time points and skin sites
so conclusions that are specific to hands are impossible. Overall,
their findings indicated key functions of the skin microbiome,
including uptake of sugars, lipids, iron, and the catabolism of lactic
acid [2]. Other functional genes were associated with acid
resistance and regulation of skin pH; indicating skin microbes
regulate functions with implications for skin health [2]. Oh et al.
[20] evaluated the functional diversity of microbial communities at
different skin sites, finding a predominance of citrate cycle
modules in communities inhabiting dry sites, including palms.
There were also general biomolecular and metabolic functions
common across several body sites [20]. Bouslimani et al. [21] used
a novel approach, mapping the metabolic components over time
for many body sites, including hands, providing a map of temporal
and biogeographical changes to metabolic constituents. Combin-
ing this with bacterial genomic and biochemical data from beauty
products showed that daily routines, particularly product use, have
a large impact on our metabolomic identity [21]. Overall, it appears
the functional component of the metagenome (the genomic
contents of an entire microbial community) varies widely, which
is not unexpected given the wide variation in the taxonomic
composition of communities [20].
3.4. Temporal dynamics of the hand microbiome
Next, we investigated how the microbiome of the hands
changes over time, and Caporaso et al. [22] provided the most
comprehensive study of how an individual’s hand microbiome
changes over time. In this study, one female and one male
participant were each sampled daily for 6 and 15 months,
respectively [22]. Their findings showed hand microbiome
composition fluctuated, however there were persistent communi-
ty members that showed up in most samples, with varied relative
abundance at any given sampling time [22]. Persistent community
members on hands included Actinobacteria, Bacteroidia,
Flavobacteria, Sphingobacteria, Cyanobacteria, Bacilli, Clostridia,
Fusobacteria, Alphaproteobacteria, Betaproteobacteria, and
Gammaproteobacteria [22]. Another study showed there is a
persistent community for some individuals, and found that
relatively abundant and persistent members include taxa within
Actinobacteria, Bacilli, and Gammaproteobacteria [23]. Skin,
including palms, harbored a characteristic microbiome over time,
with less variation over 24-h than a 3-month period [24]. Not
surprisingly, it was generally demonstrated that interpersonal
hand microbiome variation is greater than temporal variation [24–
26]. However, temporal variation on the hands is quite high with
<15% of phylotypes being found over multiple sampling periods,
and even for those phylotypes that are found at multiple time
points there can be substantial changes in their relative
abundances [23]. This high variability may be driven by higher
abundance of transient organisms present at any given time-point
[23]. Additionally, time of sampling (days to months apart) did not
significantly correlate with microbiome composition, indicating
that the hand microbiome does not change in a predictable manner
over time [23].
3.5. Biogeographical dynamics of the hands compared to other body
sites
Skin biogeography significantly impacts the composition of the
microbiome, twelve studies that evaluated the hands and other
skin sites determined that the hands have a unique microbiome.
Hands have greater bacterial diversity; and the hand microbiome is
more dynamic over time than other skin sites [22–24,27]. Palm
skin typically harbors >3 times more bacterial phylotypes per
individual compared to forearm or elbow skin [25,27]. Fungal
species diversity was intermediate on hands, with feet having
greater diversity and core body skin sites having the least diversity
[19]. Microbial communities on hands were generally enriched
with different bacterial taxa compared with other body sites
[17,18,24,25], and acquired a larger pool of total bacterial species
through time [23]. The interpersonal variation of the hand
microbiome was less than the variation between different body
sites on the same individual [24,25]. Temporal stability of the
microbiome is dependent on physiological conditions of the skin;
with moist, warm, and nutritionally rich skin sites harboring a
more stable microbiome than hands which are dry and continually
exposed to varying environments [22,27]. Additionally, individuals
with more variable hand bacterial communities have greater
variability at other skin sites, indicating microorganisms may be
transferring between skin sites [23].
Not only does the microbiome vary with geographical body
location, but the layers of skin at different depths may harbor
compositionally distinct microbiomes. The impact of skin depth
was exhibited by the significant difference in the microbiome
observed between identical samples obtained with glove juice
S.L. Edmonds-Wilson et al. / Journal of Dermatological Science 80 (2015) 3–12
7
Table 2
Summary of relative abundance
*
(in percent) of microorganisms found on hands at family level..
Phylum Class Order Family Bouslimani
et al. [21]
Caporaso
et al. [22]
Costello
et al.
[24]
Fierer
et al.
[17]
Findley
et al.
[19]
Flores
et al.
[23]
Grice
et al.
[25]
Hospodsky
et al. [32]
Meadow
[30]
Oh
et al.
[20]
Song et al. [29]
Persistent Transient US Tanzania Infant Child Adult Senior
Actinobacteria Actinobacteria Actinomycetales Actinomycetaceae 0.5 1.3 1.8 2.0 2.0
Corynebacteriaceae 3.3 2.4 4.3 7.7 10.5 10.4 2.1 23.6 4.6 3.0 4.2 4.3
Nocardiaceae 12.4
Intrasporangiaceae 1.1
Micrococcaceae 1.7 3.7 1.7 2.9 14.4 7.6 2.0 4.7 3.9 2.8 2.7
Propionibacteriacea 37.4 31.6 47.8 15.4 15.2 3.9 3.1 11.0 27.0 20.0
Other (within
Phylum)
3.4 21.3 18.6 6.1 1.3 2.7
Bacteroidetes Bacteroidetes Bacteroidales Bacteroidaceae 2.1 5.3 1.6 1.6 3.4
Porphyromonadaceae 1.1 2.0 1.9 1.4
Prevotellaceae 1.1 1.0 1.6 2.0 5.6 4.2 3.1 2.1
Flavobacteria Flavobacteriales Flavobacteriaceae 2.6 1.8 1.7 1.2 10.8 3.4 1.0 1.9 2.7 3.8
Sphingobacteria Sphingobacteriales Sphingobacteriaceae 2.5 2.4
Other (within
Phylum)
27.0
Firmicutes Bacilli Bacillales Bacillaceae 9.7 1.0 6.5 1.2
Exiguobacteraceae 2.2
Gemellaceae 1.1
Planococcaceae 2.2
Staphylococcaceae 1.7 3.6 8.3 12.2 11.2 8.5 28.2 4.5 24.7 8.7 3.2 5.1 6.7 2.8
Other (within Order) 35.7 10.0
Coccus Lactobacillades Carnobacteriaceae 3.9 1.3 6.4 5.0 1.7 1.0
Streptococcaceae 3.7 8.3 17.2 7.6 11.7 15.1 27.3 49.0 27.0 15.0 13.0
Aerococcaceae 1.6
Lactobacillaceae 4.1 4.2 5.8 7.1 3.1 1.5 4.2
Clostridia Clostridiales Acidaminacoccaceae 1.1
Clostridiaceae 1.7 6.5 9.4 3.3
Lachnospiraceae 1.6 1.0 1.0 3.1
Peptostreptococcaceae 1.2
Veillonellaceae 2.1 1.6 2.2 5.5 2.2 1.7 1.9
Other (within Order) 2.0 2.5 1.5 1.0 1.4
Other (within
Phylum)
18.4 1.5 3.1
Proteobacteria Alpha-
proteobacteria
Caulobactereales Caulobactereaceae 3.0
Rhodospirillales Acetobacteraceae 1.6
Rhodobacterales Rhodobacteriaceae 21.0
Rhizobiales Bradyrhizobiaceae 1.2 4.5
Brucellaceae 4.6
Rhizobiaceae 4.0
Sphingomonadales Sphingomonadaceae 1.1 1.0 1.1 3.2
Other (within Order)
Other (within
Class)
4.2 1.2 6.3 1.1 1.8
Beta-
proteobacteria
Burkholderiales Comamonadaceae 4.0 1.5 3.6
Other (within order) 3.1 1.0 12.7
Neisseriales Neisseriaceae 2.3 3.8 2.0 1.4 4.8 2.6 3.5 1.6 2.0
Other (within
Class)
1.5 3.4 12.1 22.8
Gamma-
proteobacteria
Aeromonadales unknown 1.1
S.L. Edmonds-Wilson et al./ Journal of Dermatological Science 80 (2015) 3–12
8
sampling and swabbing; indicating that deeper layers of the
epithelium (contained in glove juice) contain a microbiome that is
different from that obtained at the surface (swab) [26]. Additional-
ly, Nakatsuji et al. [28] found bacteria in sub-epidermal compart-
ments of palm skin to have distinct bacterial communities
compared to those found on exposed areas of skin.
3.6. Intrinsic factors impacting hand microbiome composition
Two studies investigated the impact of age on the hand
microbiome with mixed results. One found no impact of age on the
hand microbiome, however all subjects in the study were adults,
ages 20–59 [26]. Another study that evaluated a wider age range
showed an insignificant effect of age on hand microbiome diversity
and composition; however there were shifts in the relative
abundance of organisms with the hands of infants and children
having greater proportions of Firmicutes (including Carnobacter-
iaceae, Streptococcaceae, and Veillonellaceae), and the hands of
adults and the elderly having higher proportions of Propionibac-
teriaceae [29].
Three studies investigated gender impacts on the hand
microbiome composition, and overall men and women harbor
distinct bacterial communities. One study showed significant
gender effects on the hand microbiome, with Propionibacteria and
Corynebacterium, more abundant on male hands, and Enterobac-
teriales, Moraxellaceae, Lactobacillaceae and Pseudomonaceae
more abundant on female hands [17]. The palms of women had a
more diverse bacterial composition than those of men [17,29]. This
finding was further supported by studies showing a significant
difference in the composition of the bacterial microbiome of the
hands of adult males versus females [29,30]. Gender differences
were also observed with interactions with inanimate objects, as
the bacterial composition of female hands was significantly more
like their mobile phones, than the similarity in bacterial
composition of male hands to their phones [30].
Immune function and other health factors likely impact the
bacterial composition of hand skin. A study found different
bacterial composition on the hands of healthy controls compared
with those of immune-compromised individuals; with healthy
populations having greater proportions of Staphylococcus spp.,
Fusobacterium spp. and Prevotella spp., and the immune-compro-
mised having a greater proportion of Acinetobacter spp. [31].
Only one study investigated whether a person’s dominant hand
had an impact on the bacterial community of the hand [17]. They
found significantly more Lactobacillaceae, Enterobacteriales,
Peptostreptococcaceae, and Xanthomonadales on the dominant
hand [17]. However this difference may be indicative of an
extrinsic, environmental impact since the dominant hand is more
likely to be picking up transient microorganisms from the
surrounding environment.
3.7. Extrinsic factors impacting hand microbiome composition
No studies in this review directly evaluated the impact of hand
hygiene or other product use on the hand microbiome; however via
self-reported survey data, researchers attempted to correlate hand
hygiene practices, including the type of products used and the
frequency of use, to changes in the hand microbiome. Healthcare
workers likely have greater exposure to hand hygiene products
than the rest of the population; however the overall microbial
diversity on hands was unchanged with alcohol-based hand rub use
or hand washing, with the exception that overall diversity was
lower in those that reported >40 hand washing with soap and
water events per shift [18]. The length of time since the last hand
washing event impacted bacterial composition, with Propionibac-
teria, Neisseriales, Burkholderiales and Pasteurellaceae more
Enterobacteriales Enterobaceriaceae 1.2
Pseudomonadales Pseudomonodaceae 1.4 1.3 3.8 1.1 2.4
Moraxellaceae 1.6 2.7 4.5 2.4 2.4 1.5 1.2 3.2 3.3
Pasteurellales Pasteurellaceae 4.0 1.1 1.5 3.7 5.7 2.6 4.4 1.8 1.2
Xanthomonodales Xanthomonadaceae 1.3 12.1 1.8
Other (within
Class)
1.0 10.1 25.7 13.9
Other (within
Phylum)
47.9
Fusobacteria Fusobacteriaceae 2.5 3.6 1.6 1.8 1.4 1.0
Other Chloroflexi 13.4
Chloroplasts 11.7 1.6
Cyanobacteria 2.9 16.6
Streptophyta 7.3 5.8
Other
*
Microorganism families with % relative abundance below 1.0 were not included in this table.
S.L. Edmonds-Wilson et al. / Journal of Dermatological Science 80 (2015) 3–12
9
abundant with time since hand washing, and Staphylococcaceae,
Streptococcaceae, and Lactobacillaceae more abundant on recently
(<2 h) washed hands [17]. While there were changes in bacterial
composition with time since last hand washing, there was no
impact on the overall level of diversity on the hands [17]. Another
study found no impact on hand microbiome composition when
hand washing occurred within 1 h of sampling [30]. Frequency of
hand washing on the day prior to sampling did not correlate with
changes in bacterial composition [32]. Use of other topical products
was not studied on hands, but use of oral antibiotics had a
significant impact on the hand microbiome, with the largest shift
observable around the time of use [23].
Those who live within the same home have a more similar hand
microbiome than people who live in different homes; and couples
and their young children share more bacterial taxa than unrelated
roommates [16,29]. Additionally, owning a pet resulted in a
significant increase in shared microorganisms for people within a
household, and a person’s hand microbiome is more like their own
pet’s paws than that of a pet in another household [29]. Addition-
ally, pet ownership increases the overall diversity of bacteria on
the hands [29].
Interaction with inanimate objects is another source of
variability in the hand microbiome. A home becomes colonized
with its occupant’s microbiome, and for the majority of hand
samples, the microbiome could be matched to light switches in
their homes, indicating hands are a key vector for microbial
contamination of surfaces within the home [16]. However, there
are differences between the human microbiome and the microbial
communities found inside our homes, with Firmicutes and
Actinobacteria being more abundant on human skin relative to
surfaces in the home [29]. Personal possessions such as cell phones
and keyboards are another source of microorganisms, and studies
have even shown that objects can be identifiable to their owner
[30,33] which could make microbiome analyses of personal objects
an alternative to human DNA forensic analyses.
Significant differences based on lifestyle and/or ethnicity were
observed between the hand microbiome of Tanzanian mothers
versus American female graduate students [32]. Rhodobacteraceae,
Nocardioidaceae and Burkholderiales were enriched on Tanzanian
hands; whereas Staphylococcaceae, Propionibacteriaceae, Strep-
tococcaceae, and Xanthomonadaceae were more abundant on
hands of students in the United States [32]. Interestingly,
Rhodobacteraceae and Nocardioidaceae are typically found in
soils and the aquatic environment, indicating Tanzanian women,
who have close contact with the outside environment, acquire
these bacteria in greater proportions than American women who
primarily stay indoors [32].
4. Discussion
The hand microbiome was more variable and less stable over
time than the microbiomes of other skin sites [17,22].This
dynamic and relatively unstable nature makes it difficult to
conclude what is a ‘‘normal’’ or ‘‘healthy’’ hand microbiome.
Also, most studies that evaluated the microbial composition of
hands were looking at a single point in time. However, as day to
day variation in hand microbiome composition can be quite high,
a single time-point may not be representative, demonstrating
the importance of sampling individuals over time to elucidate a
‘‘core’’ microbiome. As evident from Table 2, there is a high
degree of variability in the composition of the hand microbiome
across studies, variability that is at least in part related to
different study populations, sampling strategies, and sequencing
approaches. For example, Propionibacteriaceae were nearly
always found in relatively high abundance when they were
present, but were only present in samples from about two-thirds
of studies, which may be a methodological artifact since some
primers are biased against Propionibacteriaceae. It is known
from previous studies that bacteria from the families of
Staphylococcaceae, Streptococcaceae, Corynebacteriacea, and
Moraxellaceae are common residents; therefore it was not
surprising that most studies found organisms from these
families. Lactobacillaceae, which tend to be anaerobic, were
found in nearly all studies, it is possible these bacteria are
transients on the hands of females, being repopulated from
resident vaginal populations.
There are many sources of variability, both intrinsic and
extrinsic, that influence the hand microbiome composition. Skin
physiology, which is impacted by both intrinsic factors (e.g.
disease, immune function, age) and extrinsic factors (e.g.
temperature, humidity, exposure to chemicals), has been shown
to impact the composition of the skin microbiome [1,34]. Therefore,
it is reasonable to hypothesize that any health or environmental
condition that impacts hand skin physiology may affect the hand
microbiome. Even the hand microbiome of the same individual
when sampled at multiple time points can exhibit significant
variation [22]. Age, handedness, and gender were intrinsic factors
that impacted the composition of the hand microbiome [17,29]. Ex-
trinsic factors, including cohabitation, familial relationships, and
pet ownership, as well as interaction with fomites and our external
environment also impacted the hand’s microbial composition
[16,30]. Considering the various surfaces our hands touch in a
typical day it is not surprising that hands exhibit such high
variation in microbial composition. Hands are like a busy
intersection, constantly connecting our microbiome to the
microbiomes of other people, places, and things. We therefore
propose a model (Fig. 2), depicting hands as the critical vector for
populating and repopulating the microbiome. Lax et al. [16]
conducted a Bayesian network analysis that demonstrates hands
as key vectors for transferring microbes to various body sites, pets
and inanimate objects within homes, which provides further
support for our model. Additionally, numerous culture-based
studies have highlighted hands as a vector for transmission of
microorganisms, including viruses [35–38]. Hands are an impor-
tant vector in populating the human microbiome, therefore future
skin microbiome studies should include hand sampling, as
knowledge of the hand microbiome is critical for understanding
overall human skin microbiome dynamics. Additionally, there is
very little known about the microbiome of diseased hand skin (e.g.
hand eczema, atopic dermatitis or psoriasis); therefore future
studies should also include investigation of differences between
healthy and diseased hand skin to further our understanding of
what residents and/or functional components of the microbiome
are important to maintain healthy skin. These studies could lead to
interventions for the prevention and/or cure of these common skin
ailments.
One limitation of this review was our inability to make
quantitative comparisons across studies due to numerous differ-
ences in test methods and presentation of data as well as the
paucity of data on microorganisms other than bacteria. There are
no standardized test methods for sampling, assessing or reporting
of microbiome data. However, a recent publication outlines critical
steps in conducting a microbiome study, and adoption of their
recommendations would increase the comparability of studies
[39]. To minimize methodological sources of variability, we need
standardized test methods similar to those that have been
developed in other areas of research by organizations such as
ASTM International. The methods employed in a study can
significantly impact results, and several studies included in this
review examined specific methodological differences. In the
following paragraphs we propose several methodological recom-
mendations for future hand microbiome studies.
S.L. Edmonds-Wilson et al./ Journal of Dermatological Science 80 (2015) 3–12
10
Not all studies included a pre-wash to remove transient
organisms before sampling; therefore a significant proportion of
microorganisms studied may have been transient taxa. This limits
our ability to make conclusions about the stability of communities
on hands and whether particular microorganisms are more like to
be transient or residents. This also makes it difficult to determine
causal relationships between interventions on hands and their
impact on hand microbiome composition. Therefore, we propose
that hand sampling studies focused on the resident microbiome
have test participants undertake a prewash with non-antimicro-
bial soap to remove transients prior to sampling.
The skin sampling methods used in the studies in this review
were of 4 types: punch biopsy, glove juice, scrapping or swab (most
to least invasive). Nearly all studies used the swab method to
assess microbial composition. No differences were found in the
types of bacteria found between swabbing and scraping [8],
however there were significant differences between swabbing and
glove juice sampling methods [26]. Swabbing only samples the
skin surface where the swab touches, whereas the glove juice
method samples the entire hand and is more aggressive, exposing
more of the epithelial skin layers. Therefore, we should consider
the possibility that data solely from swabs may overestimate the
transient nature of the hand microbiome; since swabbing does not
access microbes present in the deeper layers of skin which may
house resident microbes that are likely more stable over time.
Therefore, we propose the glove juice sampling method be used in
combination with swabbing or in place of swabs for assessing the
hand microbiome.
Current studies relied on self-reported data collected in surveys
for assessing the impact of product use on the hand microbiome.
Self-reported data can be inaccurate [40], therefore future studies
that investigate the impact of products or other interventions on
the hand microbiome should not rely solely on self-reported
survey data but should be conducted in controlled laboratory-
based settings or be case-controlled clinical studies.
Most studies in this review focused on young adults (typically
professionals or students) in the United States. Additionally, the
sample size for most studies was quite small. This makes it difficult
to interpret results and generalize to other populations. It is
recommended that future studies attempt to enroll a broader
diversity of test participants to make results more generalizable.
Finally, only three studies in this review focused on the function
of constituents of the microbiome. As we advance our under-
standing of microbiome dynamics, it will be critical to improve our
understanding of the functional aspects of the microbiome using
metabolomics and other emerging technologies. Emerging tech-
nologies are increasing our ability to mine databases to determine
function of unknown metabolites; and tools are being developed
that enable linkage of metabolite (and functional) data to specific
microorganisms [21]. Therefore, the determination of key micro-
biome functions and how they can be manipulated will likely lead
to new diagnostic approaches and new strategies for managing the
hand microbiome.
As the scientific community embraces emerging technologies it
is only a matter of time before products are developed that could
change the hand microbiome composition for improved health
outcomes or to assist in repopulating our microbiome after
antibiotic use and/or illness. It is possible that assessing our hand
microbiome at any given point in time could provide us with
valuable information about our health status and/or environment
which could lead to the use of our hand microbiome as a diagnostic
tool and preventive health measure. Given the individual nature of
our hand microbiome [33,41], using the hand microbiome and
comparing it to surface microbiomes could become common as a
[(Fig._2)TD$FIG]
Fig. 2. Proposed model for the hand as a critical vector in microbiome dynamics.
S.L. Edmonds-Wilson et al. / Journal of Dermatological Science 80 (2015) 3–12
11
forensic application even more powerful than human DNA
analysis. Our hands influence the microbiome of every surface
we touch, leaving and picking up microbes with each touch. Using
standardized methods and conducting larger studies in more
populations will increase our understanding of the normal
microbiome of hands, how it can be manipulated, and the impact
of manipulation on health outcomes.
In conclusion, the hands are a critical component of the human
microbiome. This is an area of study that has been under-
represented in the scientific literature, and we strongly recom-
mend an increased focus on hand microbiome and metabolomics
studies, in order to better address the question, ‘‘What is a healthy
hand microbiome’’?
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Sarah L. Edmonds-Wilson is a Senior Clinical Scientist
at GOJO Industries. She has significant experience in the
development and testing of antimicrobial products,
with over 70 presentations at leading scientific con-
ferences and peer-reviewed journal publications on
these topics. Her abstract ‘‘Comparative Efficacy of
Commercially Available Alcohol-based Handrubs and
WHO-Recommended Handrubs: Which is More Criti-
cal, Alcohol Content or Product Formulation?’’ won the
William A. Rutala Research Award and a Blue Ribbon
Abstract Award at APIC in 2011. Sarah holds her
Master’s degree in Biology from the University of Akron,
and an undergraduate degree in Biology.
S.L. Edmonds-Wilson et al./ Journal of Dermatological Science 80 (2015) 3–12
12
... Assim, conhecer os microrganismos existentes nas mãos dos profissionais de saúde contribui para controle das IRAS. Além disso, contribui também para os avanços na ciência na busca por novas soluções, como com o desenvolvimento de produtos para prevenção e tratamento de doenças e outras aplicações, incluindo novas abordagens de diagnóstico e forenses (Edmonds-Wilson et al., 2015). ...
... As coletas das amostras biológicas das mãos dos profissionais de enfermagem se deram em dias e ordens aleatórias, sendo analisada a mão dominante dos participantes que assinaram o Termo de Consentimento Livre e Esclarecido. A mão dominante foi a escolhida uma vez que esta tem maior probabilidade de coletar microrganismos transitórios do ambiente circundante (Edmonds-Wilson et al., 2015). Dessa forma, incluiu-se na pesquisa, profissionais sem ferimentos na mão e que não fizeram uso de antibióticos nos últimos 15 dias antes da coleta. ...
... Apesar da importância das mãos como uma fonte de transmissão de infecções, existem poucas revisões abordando os avanços da composição da microbiota das mãos e dos fatores que a influenciam (Edmonds-Wilson et al., 2015). Estudos in vitro, utilizando diferentes cepas de bactérias multirresistentes, mostraram que, apesar de resistentes aos antibióticos, essas bactérias permanecem sensíveis aos antissépticos utilizados na HM (Brasil, 2009). ...
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Apesar de existirem diferentes metodologias para coleta de microrganismos das mãos, há carência de estudos comparativos. Nesse sentido, objetivamos quantificar potenciais cepas patogênicas nas mãos de profissionais de enfermagem de um hospital público do Sul do Brasil, a partir da avaliação comparativa de métodos de coleta. Para isso, realizamos um estudo transversal, experimental e quali-quantitativo, durante o ano de 2019, sob aprovação do Comitê de Ética e Pesquisa com Seres Humanos. Comprovamos que enxágue com luva é a metodologia indicada para coletas microbiológicas das mãos, já que recuperou 42,19% dos microrganismos, enquanto o swab recuperou 1,91%. A partir disso, realizamos coletas, quantificação e identificação de microrganismos nas mãos de profissionais de enfermagem. Para os microrganismos aeróbios mesófilos a quantificação variou de 5X104 a 4X106 UFC/mão, para os Staphylococcus coagulase positiva variou de 5X104 a 3X106 UFC/mão e para os fungos de 5X104 a 2X106 UFC/mão. Dentre os fungos as leveduras dominaram em 93,73%, sendo identificado, com frequência, o gênero Candida spp. Não foram encontrados coliformes totais e termotolerantes. Staphylococcus aureus estiveram em 90,91% das mãos, sendo realizado Teste de Sensibilidade aos Antibióticos em 25 colônias isoladas, todas testando resistência a pelo menos três classes de antibióticos, mostrando serem multirresistentes. A análise dos dados mostrou que o melhor método de coleta é o de enxágue com luva, pois recupera maior quantidade e diversidade microbiana que o método comparado. Além disso, foi possível observar a importância das mãos como fontes de contaminação cruzada entre pacientes.
... The hand represents a critical connection between humans and the external world and plays a vital role as a vector by which microorganisms are transmitted among body sites, individuals, items, and the environment (11). The hand microbiota could thus contribute to the formation of a microbial fingerprint on our possessions (12). ...
... Smartphones are portable devices that can exert extensive effects on the environment and humans. For example, standardized hand washing/hygiene practices can efficiently reduce or even kill foreign bacteria from the environment, thus restoring the hand microbiota to a natural skin microbiome and decreasing the risk of pathogens spreading to other body parts by the hands (11). Nonetheless, frequent contact with smartphones could undermine hand hygiene efforts since hands can reacquire contaminants and perhaps pathogenic microbiotas from the smartphone reservoir of microbes. ...
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Smartphone usage and contact frequency are unprecedentedly high in this era, and they affect humans mentally and physically. However, the characteristics of the microorganisms associated with smartphones and smartphone hygiene habits remain unclear. In this study, using various culture-independent techniques, including high-throughput sequencing, real-time quantitative PCR (RT-qPCR), the ATP bioluminescence system, and electron microscopy, we investigated the structure, assembly, quantity, and dynamic metabolic activity of the bacterial community on smartphone surfaces and the user’s dominant and nondominant hands. We found that smartphone microbiotas are more similar to the nondominant hand microbiotas than the dominant hand microbiotas and show significantly decreased phylogenetic diversity and stronger deterministic processes than the hand microbiota. Significant interindividual microbiota differences were observed, contributing to an average owner identification accuracy of 70.6% using smartphone microbiota. Furthermore, it is estimated that approximately 1.75 × 106 bacteria (2.24 × 104/cm2) exist on the touchscreen of a single smartphone, and microbial activities remain stable for at least 48 h. Scanning electron microscopy detected large fragments harboring microorganisms, suggesting that smartphone microbiotas live on the secreta or other substances, e.g., human cell debris and food debris. Fortunately, simple smartphone cleaning/hygiene could significantly reduce the bacterial load. Taken together, our results demonstrate that smartphone surfaces not only are a reservoir of microbes but also provide an ecological niche in which microbiotas, particularly opportunistic pathogens, can survive, be active, and even grow.
... The hand is a vehicle of transmission of pathogens, microorganisms, bacteria, viruses, and infections from one person to another, from one patient to another, from one patient to another via a nurse or a doctor, from a patient to a doctor or a nurse, from a doctor or a nurse to a patient, from one family member to another, and from one neighbour to another [1]. Transmission may occur when the hand of an uninfected person directly touches the hand of an infected person or catches fluid or secretion from an infected person. ...
... A simple, affordable and effective means of curbing the spread of diseases is hand hygiene [1,2,3,4,5,6,7]. Hand washing with running water and soap is a confirmed way of stopping the spread of diseases among people. ...
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The hand is a vehicle for transmission of diseases from one person to another; either by direct contact or indirectly by touching contaminated surfaces. A simple, affordable and effective means of curbing the spread of diseases is hand hygiene which is regarded as a “Do-it-yourself-Vaccine” in Public Health. Proper hand washing requires soap and running water. COVID‐19 pandemic increased the awareness, importance, use, and demand for hand washing stations. The fight against COVID-19 gave birth to innovations in Africa for local development of hand washing stations, ventilators and other life-saving medical devices. Buckets are seen in schools, churches, mosques, health centers and other public places as hand washing has become a requirement to gain entrance into such places. It is high time African urban centers move away from bucket-and-bow-based hand washing stations and mechanical-pedals-based hand washing stations. The development of an electronic-signal-processing-based hand washing station is presented. Ultrasonic sensors are used to detect the presence of hands. The signals from the sensors are further processed and a microcontroller in a brain box (electronic control circuit) makes decisions to command actuators to dispense liquid soap, clean water, or switch ON a fan on request. The hand washing is contact-free and the used water is properly channeled away to the drainage system. Wastage of soap is avoided through efficient software developed for the microcontroller. The automated hand washing station is functional and affordable.
... Hands are playing important role in microbial transmission in the same person's body or between persons and between persons and touched things (Edmonds-Wilson et al., 2015). Alcohol-based hand sanitizers have an inhibitory ability against many Gram-negative and Gram-positive bacteria (Gold and Avva, 2018). ...
... from 50 to 3.125 mg/ml, like Table 6, the mixture showed clear inhibition in most of the concentrations and low concentrations had the best results (Fig. 3). The human hand, especially the palm of the hand, played a major role in the transmission of germs to the rest of the body parts of the individual or between individuals or from inanimate surfaces to people (Edmonds-Wilson et al., 2015). In this research, as a result of the high percentage of E. coli and C. freundii within the microorganisms isolated from the palm of the hand of 50 adults, which were selected to test the ability of two types of alcoholbased hand sanitizers to inhibit and to develop hand sterilizers using plant extracts; T. polium was selected for its anti-bacterial properties, as its aerial parts contained saponin, ethyl phenol, monoterpenoid and sesquiterpenes (Elmasri, 2015). ...
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The present research aimed at increasing the antimicrobial efficiency of alcohol-based hand sanitizers by mixing them with ethanol and hexane crude extracts of Teucrium polium leaves. Bacterial samples were collected from the palm of the hands of 50 people to both sexes and it was found that Escherichia coli and Citrobacter freundii were present (76 and 68%). Ethanol and hexane of leaf extracts were used at concentrations (50, 25, 12.5, 6.25 and 3.125 mg/ml). The inhibitory activity was studied using the agar well diffusion method and the new mimic method which simulated the process of wiping hands with sterilizer. The results of the first method showed that the ethanol and hexane extract of the leaves of this plant had a different inhibition effect for both bacteria, where the low concentrations of 3.125 mg/ ml showed the best inhibition compared to the rest of the concentrations with inhibition diameter 21 and 23 mm for the ethanol extract and 28 and 25 mm for the hexane extract. The results of the second method confirmed that where the concentration of 3.125 mg/ml strong inhibition, and when mixing hand sanitizer with these concentrations of extracts and using both methods, the inhibitory effect increased better than using hand sanitizer alone or extracts alone and in preference to concentration 3.125 mg/ml. It can be concluded that mixing the extracts of T. polium plant with the alcohol-based hand sanitizer led to an increase in its effectiveness in inhibiting the growth of E. coli and C. freundii.
... Healthcare workers (HCWs) are the frontline fighters during COVID-19 pandemic, so they are more likely to get infected with SARS-CoV-2 which appears to be transmitted primarily through respiratory droplets, from face-to-face contact and, to a lesser extent, through contaminated surfaces. Our hands are the most critical body part for transferring pathogens [3,8]. Several methods have been suggested to relower the rate of SARSCoV-2 transmission such as hand hygiene practice (HHP), social distancing, the use of gloves etc [6]. ...
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Introduction The hand hygiene practice (HHP) is the most effective and simplest preventive measure to reduce the risk of infection. HHP is more relevant among pediatric physicians in the context of the COVID-19 pandemic since, children are more vulnerable to infection. Therefore, assessment of the COVID-19 impact on HHP could be useful in minimizing lethal virus transmission from pediatric physicians to patients and vice versa. Method The present cross-sectional, electronically self-administered supplement based survey study was conducted among different professional levels of pediatric physicians involving consultants, specialists, and residents. The supplement includes information related to demography, knowledge, awareness, preventive measures, demonstration and practice of HHP. The information was collected and summarized on a Microsoft excel sheet before being imported to SPSS for statistical analysis. Results Of the total (N = 404) pediatric physicians, 56.68% male, 43.06% belongs to 25–35 years, 42.32% were consultants, 98.01% respondents were familiar with five moments of HHP. Further, HHP immediately before touching patients (99.26%), clean/aseptic procedure (95.04%), after body fluid exposure (72.28%), after touching patients (98.01%), after touching surrounding of patients (74.75%) may prevent germ transmission to patients whereas HHP after touching patients (98.27%), before clean/aseptic procedure (67.57%), after exposure to immediate surroundings of patients (97.02%) may prevent germ transmission to pediatric physicians. Rubbing hands is preferred before palpation of abdomen (74.25%), before giving injection (56.68%), after removing gloves (61.88%), after making a patient's bed (47.80%), while washing of hands preferred after emptying bedpan (67.82%) and after visible exposure to blood (84.40%), 92.57% believed gloves can't replace HHP, posters display at point of care as reminders (95.30%), received frequent HHP education (82.92%), 50.49% do not need HHP reminder, 51.73% preferred alcohol based sanitizer, 53.46% facilitate daily morning huddle, HHP >10 times per day before COVID-19 (24.62%) while in COIVID-19 (56.44%). HPP is the most effective way to prevent the spread (98.01%) of microbes because it kills germs (90.35%), health care associated infections is the major (38.06%) cause of germ transmission, 86.88% will be remains committed to HHP even after pandemic. In comparison to residents and specialists, consultants gave more importance (p = 0.02) to HHP and were more adherent during (p = 0.007) and even after (p = 0.001) COVID-19 pandemic. Conclusion Assessing knowledge of pediatric physician, awareness, and adherence to hand hygiene measures could be helpful to reduce the contact transmission of lethal viruses to patients and vice versa. Further increase in the awareness, knowledge and education of HHP are required in order to maximize its utilization.
... Bacterial resistance was evaluated according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. [6] The occurrence of resistance mechanisms on isolates was investigated (methicillin-resistant Staphylococcus aureus. ...
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Objectives: The purpose of the study was to validate the risk of patients' exposure to pathogenic flora carried on hands of students, visitors, and patients themselves, analyzing its density and genera and to compare them with the microflora of healthcare workers (HCWs). Patients and methods: Between May and June 2018, five groups of participants were included. Each group consisted of eight individuals. Palmar skin imprints were obtained from dominant hands of doctors, nurses, students, visitors, and patients in orthopedics ward. Imprints were incubated at 37°C under aerobic conditions, and colony-forming units (CFU) on each plate were counted after 24, 48, and 72 h. Microorganisms were identified. Results: Hands of doctors were colonized more often by Gram - positive non-spore-forming rods bacteria than hands of nurses (p<0.05). A higher number of Staphylococcus epidermidis CFUs was observed on doctors' than on nurses' hands (p<0.05), whereas Staphylococcus hominis was isolated from doctor's and patients' imprints, but was not from nurses' and students' imprints (p<0.05). Micrococcus luteus colonized patients' hands more often than students' (p<0.05), visitors' hands than doctors' (p<0.05), students' than nurses' (p<0.05), visitors' than nurses' (p<0.05) and patients' hands (p<0.05). Staphylococcus aureus (S. aureus) was isolated only from one doctor and one nurse (203 and 10 CFUs/25 cm2 ). Imprints taken from the hands of patients, students and visitors were S. aureus-free. No methicillin-resistant S. aureus (MRSA), vancomycin-resistant enterococci, nor expanded spectrum betalactamase-positive or carbapenemase-positive rods were isolated. The number of Gram-negative rods was the highest on visitors' hands, significantly differing from the number on patient's, doctor's, nurse's, and student's hands. Spore-forming rods from genus of Bacillus were isolated from representatives of all tested groups. Bacillus cereus occurred more commonly on visitors' hands than doctors' hands (p<0.05). Conclusion: Patients, students, and visitors may play the causal role in the spread of pathogenic bacteria, particularly spore-forming rods. Our study results confirm the effectiveness of educational activities, that is the hospital's hand hygiene program among HCWs, patients, and visitors. Hand hygiene procedures should be reviewed to put much more effort into reducing the impact of all studied groups on the transmission of infectious diseases.
... We also found hand washing prior to eating to be associated with an increased risk of type 1 diabetes in both univariate and multivariate analysis. The microbiome of skin of the hands is particularly diverse [36,37]. Handwashing prior to eating may therefore contribute to lack of diversity of the gut microbiome. ...
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Background The prevalence of type 1 diabetes is increasing worldwide, suggesting that unknown environmental factors are becoming increasingly important in its pathogenesis. Aim The aim of the study was to investigate the possible role of a number of prenatal and perinatal factors in the aetiology of type 1 diabetes. Methods Mothers of patients diagnosed with type 1 diabetes (cases) and mothers of children born on the same day and of the same sex as type 1 diabetes patients (controls) were interviewed on a number of prenatal and perinatal factors of interest. Results Hand washing prior to eating, frequency of bathing and total stress score were found to be positively associated with the development of type 1 diabetes on univariate analyses. Hand-washing prior to eating and frequency of house cleaning were independently associated with an increased risk of type 1 diabetes, whilst getting dirty was associated with a reduced risk in multivariate analyses. There was no association of type 1 diabetes to removing of outdoor shoes indoors or to the age of first attendance to school or pre-school. There were also no significant associations to parental smoking, parental age, birth order, infant feeding, antibiotic use, mode of delivery or birth weight. Conclusion Our data suggest that factors that affect the skin or gut microbiome might be more important than infections or factors affecting the microbiome at other sites.
... In 2 laboratory-based studies 29,33 participants' hands were artificially contaminated which standardized baseline bacterial load. However, using a single type of microorganism does not reflect the natural conditions and the actual bacterial flora present on HCWs' hands, 36,37 reducing the external validity of their findings. ...
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Background: This review, commissioned by the World Health Organization (WHO), examined the effectiveness of the WHO 6-step hand hygiene (HH) technique in reducing microbial load on hands and covering hand surfaces, and compared its effectiveness to other techniques. Methods: Medline, CINAHL, ProQuest, Web of Science, Mednar, and Google Scholar were searched for primary studies, published in English (1978 - February 2021), evaluating the microbiological effectiveness or hand surface coverage of HH techniques in healthcare workers. Reviewers independently performed quality assessment using Cochrane tools. The protocol for the narrative review was registered (PROSPERO 2021: CRD42021236138). Results: Nine studies were included. Evidence demonstrated that the WHO technique reduced microbial load on hands. One study found the WHO technique more effective than the 3-step technique (P=0.02), while another found no difference between these two techniques (P=0.08). An adapted 3-step technique was more effective than the WHO technique in laboratory settings (P=0.021), but not in clinical practice (P=0.629). One study demonstrated that an adapted 6-step technique was more effective than the WHO technique (P=0.001). Evidence was heterogeneous in application time, product, and volume. All studies were high risk of bias. Conclusions: Eight studies found that the WHO 6-step technique reduced microbial load on healthcare workers’ hands; but the studies were heterogeneous and further research is required to identify the most effective, yet feasible technique.
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BACKGROUND: West Java is ranked 4th as the province with the highest number of COVID-19 cases in Indonesia up to December 1, 2020. The COVID-19 pandemic has a major impact on human health, lifestyle changes, and economic life. AIM: The purpose of this study was to analyze the impact of the COVID-19 pandemic on lifestyle changes among the community of West Java. METHODS: The study was conducted in September 2020 using a cross-sectional study design. A total of 2502 people aged ≥12 years living in West Java were involved in this study as a sample, willing to fill out a questionnaire in the form of a Google form that was distributed online through social media (WhatsApp, Facebook, and Instagram). RESULTS: The results showed that the COVID-19 pandemic had an effect on lifestyle changes in the people of West Java. During the COVID-19 pandemic, the people of West Java became more frequent to wash their hands, do regular exercise, sunbathe in the morning, consume more vegetables and fruits, and consume vitamins or supplements to increase endurance (p < 0.05). CONCLUSION: Based on the result, the community should continue to improve the COVID-19 prevention practices in breaking the chain of transmission.
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The human face/head supports a highly diverse population of microorganisms across a diverse range of microhabitats. This biogeographical diversity has given rise to selection pressure resulting in the formation of distinct bacterial communities between sites. This review investigates the similarity and differences of microbiomes across the different biogeographies of the human face and discusses a potential pathway for microbial circulation within individuals and within a population to maintain microbiome niches and diversity.
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Community composition within the human microbiome varies across individuals, but it remains unknown if this variation is sufficient to uniquely identify individuals within large populations or stable enough to identify them over time. We investigated this by developing a hitting set-based coding algorithm and applying it to the Human Microbiome Project population. Our approach defined body site-specific metagenomic codes: sets of microbial taxa or genes prioritized to uniquely and stably identify individuals. Codes capturing strain variation in clade-specific marker genes were able to distinguish among 100s of individuals at an initial sampling time point. In comparisons with follow-up samples collected 30-300 d later, ∼30% of individuals could still be uniquely pinpointed using metagenomic codes from a typical body site; coincidental (false positive) matches were rare. Codes based on the gut microbiome were exceptionally stable and pinpointed >80% of individuals. The failure of a code to match its owner at a later time point was largely explained by the loss of specific microbial strains (at current limits of detection) and was only weakly associated with the length of the sampling interval. In addition to highlighting patterns of temporal variation in the ecology of the human microbiome, this work demonstrates the feasibility of microbiome-based identifiability-a result with important ethical implications for microbiome study design. The datasets and code used in this work are available for download from huttenhower.sph.harvard.edu/idability.
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The human skin is an organ with a surface area of 1.5-2 m(2) that provides our interface with the environment. The molecular composition of this organ is derived from host cells, microbiota, and external molecules. The chemical makeup of the skin surface is largely undefined. Here we advance the technologies needed to explore the topographical distribution of skin molecules, using 3D mapping of mass spectrometry data and microbial 16S rRNA amplicon sequences. Our 3D maps reveal that the molecular composition of skin has diverse distributions and that the composition is defined not only by skin cells and microbes but also by our daily routines, including the application of hygiene products. The technological development of these maps lays a foundation for studying the spatial relationships of human skin with hygiene, the microbiota, and environment, with potential for developing predictive models of skin phenotypes tailored to individual health.
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Background It is now apparent that the complex microbial communities found on and in the human body vary across individuals. What has largely been missing from previous studies is an understanding of how these communities vary over time within individuals. To the extent to which it has been considered, it is often assumed that temporal variability is negligible for healthy adults. Here we address this gap in understanding by profiling the forehead, gut (fecal), palm, and tongue microbial communities in 85 adults, weekly over 3 months. Results We found that skin (forehead and palm) varied most in the number of taxa present, whereas gut and tongue communities varied more in the relative abundances of taxa. Within each body habitat, there was a wide range of temporal variability across the study population, with some individuals harboring more variable communities than others. The best predictor of these differences in variability across individuals was microbial diversity; individuals with more diverse gut or tongue communities were more stable in composition than individuals with less diverse communities. Conclusions Longitudinal sampling of a relatively large number of individuals allowed us to observe high levels of temporal variability in both diversity and community structure in all body habitats studied. These findings suggest that temporal dynamics may need to be considered when attempting to link changes in microbiome structure to changes in health status. Furthermore, our findings show that, not only is the composition of an individual’s microbiome highly personalized, but their degree of temporal variability is also a personalized feature. Electronic supplementary material The online version of this article (doi:10.1186/s13059-014-0531-y) contains supplementary material, which is available to authorized users.
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Human-associated bacteria dominate the built environment (BE). Following decontamination of floors, toilet seats, and soap dispensers in four public restrooms, in situ bacterial communities were characterized hourly, daily, and weekly to determine their successional ecology. The viability of cultivable bacteria, following the removal of dispersal agents (humans), was also assessed hourly. A late-successional community developed within 5 to 8 h on restroom floors and showed remarkable stability over weeks to months. Despite late-successional dominance by skin- and outdoor-associated bacteria, the most ubiquitous organisms were predominantly gut-associated taxa, which persisted following exclusion of humans. Staphylococcus represented the majority of the cultivable community, even after several hours of human exclusion. Methicillin-resistant Staphylococcus aureus (MRSA)-associated virulence genes were found on floors but were not present in assembled Staphylococcus pan-genomes. Viral abundances, which were predominantly enterophages, human papilloma virus, and herpesviruses, were significantly correlated with bacterial abundances and showed an unexpectedly low virus-to-bacterium ratio in surface-associated samples, suggesting that bacterial hosts are mostly dormant on BE surfaces.
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The bacteria that colonize humans and our built environments have the potential to influence our health. Microbial communities associated with seven families and their homes over 6 weeks were assessed, including three families that moved their home. Microbial communities differed substantially among homes, and the home microbiome was largely sourced from humans. The microbiota in each home were identifiable by family. Network analysis identified humans as the primary bacterial vector, and a Bayesian method significantly matched individuals to their dwellings. Draft genomes of potential human pathogens observed on a kitchen counter could be matched to the hands of occupants. After a house move, the microbial community in the new house rapidly converged on the microbial community of the occupants’ former house, suggesting rapid colonization by the family’s microbiota.
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Most people on the planet own mobile phones, and these devices are increasingly being utilized to gather data relevant to our personal health, behavior, and environment. During an educational workshop, we investigated the utility of mobile phones to gather data about the personal microbiome - the collection of microorganisms associated with the personal effects of an individual. We characterized microbial communities on smartphone touchscreens to determine whether there was significant overlap with the skin microbiome sampled directly from their owners. We found that about 22% of the bacterial taxa on participants' fingers were also present on their own phones, as compared to 17% they shared on average with other people's phones. When considered as a group, bacterial communities on men's phones were significantly different from those on their fingers, while women's were not. Yet when considered on an individual level, men and women both shared significantly more of their bacterial communities with their own phones than with anyone else's. In fact, 82% of the OTUs were shared between a person's index and phone when considering the dominant taxa (OTUs with more than 0.1% of the sequences in an individual's dataset). Our results suggest that mobile phones hold untapped potential as personal microbiome sensors.
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Background: Skin is our first line of defense against pathogenic microorganisms and the intimate contact between the epidermis and microbes has been well known. Purposes: Microbes that cause infection are associated with inflammatory dermatoses and exacerbate wound healing. It is therefore of vital importance to understand the intricacies of skin-microbiota interactions. However, until recently our knowledge and understanding was limited by being unable to deal with uncultivatable microorganisms, which constitute a large majority. Basic procedures: Recent advances in DNA sequencing methodologies, analysis tools and affordability led to major breakthroughs in defining the cutaneous microbiome. Main findings: We now know that four phyla, Actinobacteria, Firmicytes, Proteobacteria and Bacteroidetes, constitute preponderance of skin bacteria, while Malassezia dominates the fungal microbiome. We know that there are some 300 different bacteria inhabiting our skin. We also know that there is remarkable interpersonal variation, that the microbiota change over time, that different body sites harbor specific microbial arrays and that microbiota characteristically change in skin diseases. Principal conclusions: The recent advances led to appreciation that microbes are, for the most part, our allies, useful and protective, and that with increased understanding we will be able to harness our cutaneous friends to maintain and promote our health.