ArticlePDF Available

Bacterial contamination of computer keyboards and mice, elevator buttons and shopping carts

DOI:10.5897/AJMR11.770
Authors:
Ahmed A Alghamdi at King Abdulaziz University
Ahmed A Alghamdi
S M A Abdelmalek
S M A Abdelmalek
S M A Abdelmalek
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Ahmad Mohammad Ashshi at Umm Al-Qura University
Ahmad Mohammad Ashshi
Hani Faidah at Umm Al-Qura University
Hani Faidah
Show all 6 authorsHide
Download full-text PDF
Read full-text
Download citation

Abstract and Figures

This study aims at investigating the status of bacterial contamination of four daily used objects, computer keyboards, computer mice, elevator buttons and shopping carts handles. A total of 400 samples were collected from 4 different objects; 100 from each. Samples were collected from different places (offices, internet cafes, homes, buildings and supermarkets) in the city of Jeddah, Saudi Arabia. 95.5% of the total samples collected were contaminated with mixed bacterial growth. Coagulase-negative staphylococci dominated the isolates. The second most common bacterial growth in all specimens was Gram-positive bacilli. Potential pathogens isolated from all specimens were: Staphylococcus aureus, Pseudomonas spp. and Gram negative bacilli. Results indicate that internet café computer keyboards and mice showed 100% contamination in comparison with other objects. The presence of pathogenic and commensal bacteria on the four objects indicates that they might act as environmental vehicles for the transmission of potentially pathogenic bacteria.
Figures - uploaded by Hani Faidah
Author content
All figure content in this area was uploaded by Hani Faidah
Content may be subject to copyright.
Content uploaded by Hani Faidah
Author content
All content in this area was uploaded by Hani Faidah
Content may be subject to copyright.
African Journal of Microbiology Research Vol. 5(23), pp. 3998-4003, 23 October, 2011
Available online http://www.academicjournals.org/ajmr
ISSN 1996-0808 ©2011 Academic Journals
Full Length Research Paper
Bacterial contamination of computer keyboards and
mice, elevator buttons and shopping carts
A. K. Al-Ghamdi1, S. M. A. Abdelmalek2* A. M. Ashshi3, H. Faidah3, H. Shukri4 and
A. A. Jiman-Fatani4
1College of Applied Medical Sciences, King Abdulaziz University Jeddah, Saudi Arabia.
2Faculty of Pharmacy and Biomedical Sciences, University of Petra, Amman Jordan.
3College of Applied Medical Sciences, Umm Al-Qura University, Mecca, Saudi Arabia.
4King Abdulaziz University Hospital, Saudi Arabia.
Accepted 26 September, 2011
This study aims at investigating the status of bacterial contamination of four daily used objects,
computer keyboards, computer mice, elevator buttons and shopping carts handles. A total of 400
samples were collected from 4 different objects; 100 from each. Samples were collected from different
places (offices, internet cafes, homes, buildings and supermarkets) in the city of Jeddah, Saudi Arabia.
95.5% of the total samples collected were contaminated with mixed bacterial growth. Coagulase-
negative staphylococci dominated the isolates. The second most common bacterial growth in all
specimens was Gram-positive bacilli. Potential pathogens isolated from all specimens were:
Staphylococcus aureus, Pseudomonas spp. and Gram negative bacilli. Results indicate that internet
café computer keyboards and mice showed 100% contamination in comparison with other objects. The
presence of pathogenic and commensal bacteria on the four objects indicates that they might act as
environmental vehicles for the transmission of potentially pathogenic bacteria.
Key words: Bacterial contamination, computers, public surfaces.
INTRODUCTION
Most people do not realize that microbes are found on
many common objects outdoors, in their offices, and
even in their homes. Such objects include; playground
equipments, ATM keyboards, kitchen sinks, office desks,
computer keyboards, escalator handrails, elevator
buttons and with the spread of supermarkets and
hypermarkets the shopping carts handles. All of the latter
objects are places that are most touched by the bare
hands of people who are in various hygienic conditions.
People believe that microbes are only present in research
labs or in hospitals and clinics and thus they have a
misleading feeling of security in other places. Lack of
knowledge about where germs prowl could be the cause
of health problems. In fact 80% of infections are spread
*Corresponding author. E-mail: sabdelmalek@uop.edu.jo. Fax:
00962-6-5715570.
Abbreviations: CK, Computer keyboards; CM, computer mice;
Shc, shopping carts; EB, elevator buttons.
through hand contact with hands or other objects
(Reynolds et al., 2005). Reynolds et al. (2005) used an
invisible fluorescent tracer for artificial contamination of
public surfaces, they found that contamination from
outside surfaces was transferred to 86% of exposed
individual's hands and 82% tracked the tracer to their
home or personal belongings hours later (Reynolds et al.,
2005). The viability of Gram-positive and some Gram-
negative organisms under various environmental condi-
tions have been described (Noskin et al., 1995). Some
microbes are infectious at very low doses and can
survive for hours to weeks on nonporous surfaces, such
as countertops and telephone hand pieces (Reynolds et
al., 2005).
Enterococci have been found to survive in dry
conditions and on various fabrics utilized in the health
care environment. Infectious doses of pathogens may be
transferred to the mouth after handling an everyday
contaminated household object (Rusin et al., 2002).
Recently Ulger et al. (2009) have demonstrated that
health care workers' hands and mobile phones were
contaminated with various types of microorganisms and
Al-Ghamdi et al. 3999
Table 1. Sites sampled for the presence of bacteria and perc entage contamination.
Site No. of samples Percentage contamination Total percentage contamination
Computer key boards
93
Homes 25 88
Offices 25 92
Internet café 50 100
Computer mice
95
Homes 25 91
Offices 25 91
Internet Café' 50 100
Shopping carts handles
93
Supermartket 1 25 89
Supermartket 2 25 95
Supermartket 3 25 95
Supermartket 4 25 92
Elevator buttons
97 Shopping Malls 50 96
Residential Buildings 50 98
concluded that mobile phones used in daily practice may
be a source of nosocomial infections in hospitals.
Scientific information about the occurrence of bacteria on
various objects outside the health care facilities is very
little and needs to be enriched in order to educate people
on the necessity of improving the habit of hand washing
to reduce microbial transmission. The aim of this study
was is to investigate the presence of bacteria on 4
different objects (computer keyboards and computer
mice, elevator buttons and shopping carts handles) that
are frequently used by people in the city of Jeddah, Saudi
Arabia.
MATERIALS AND METHODS
A total of 400 samples (100 computer keyboards (CK), 100
computer mice (CM), 100 shopping carts (Shc) and 100 elevator
buttons (EB) were collected from different places of Jeddah, Saudi
Arabia (Table 1) using sterile swabs. 30 control samples from brand
new untouched computer keyboards and computer mice were also
included.
Isolation of various bacterial contaminants from the four different
objects (CK, CM, Shc and EB) was performed through standard
techniques described by Cheesbrough (2006). Briefly, sterile water-
moistened swabs were wiped f irmly over the entire surface of the
specific object. Each swab was placed in 2 ml of brain heart
infusion broth in a sterile container, and vortexed for one minute.
Total amount of 100 µl was plated out on each of blood agar and
MacConkey agar. All samples were plated within three hours of
collection. The pairs of inoculated media were incubated aerobically
at 37°C for 24 h. Pure colonies of isolates were identified and
characterized using standard microbiological techniques
(Cheesbrough, 2006).
Statistical analysis
One-way ANOVA test was used to compare the means of all
bacteria found on computers (mouse and keyboard) at different
places (Internet Cafe, Office and Home). An alpha level of .05 was
used for all statistical tests.
RESULTS AND DISCUSSION
The 30 control samples showed no bacterial growth. The
average rate of bacterial contamination of the four objects
was 95.5% with the elevator buttons showing the highest
percentage (97%) and computer keyboards from homes
showing the least (88%) (Table 1). Qualitative analysis of
bacterial isolates revealed the abundance of normal flora
isolates belonging to Coagulase negative Staphylococci
(ConS) and Gram positive bacilli in all four objects.
Potential pathogens such as Staphylococcus aureus,
Pseudomonas spp. and Gram negative bacilli were also
isolated but in lower frequencies (Table 2). Distribution of
isolates between the four different objects was almost
identical (Figure 1). However percentage of different
isolates recorded from computer keyboards and mice of
internet cafes was significantly higher (p<0.000) than
those from houses and offices (Figures 2 and 3).
The bacterial occurrence on four commonly used public
surfaces was investigated in this study. Surfaces varied
4000 Afr. J. Microbiol. Res.
Table 2. Percentages of bacterial isolates on each object.
Isolated bacteria CK (%) CM (%) Shc (%) EB (%)
Coagulase-negative staphylococci 85 88 87 84
Gram-positive bacilli 58 60 55 60
Staphylococcus aureus 20 19 14 11
Pseudomonas spp. 11 10 10 10
Gram-negative bacilli 14 11 8 7
Percentage
Figure 1. Distribution of bacterial isolates in the four objects computer key boards (CK),
computer mice (CM), shopping cart handles (SCH) and elevator buttons (EB).
between computer keyboards, mice, shopping cart
handles and elevator buttons. All tested surfaces were
found to be contaminated with mixed growth. Gram +ve
and G-ve pathogenic and non-pathogenic bacteria were
isolated. The distribution of isolates on different surfaces
was similar (Figure 1). Qualitative bacterial analysis of
the isolates on the four different objects revealed that
CoN-Staphylococci followed by Gram +ve bacilli were the
most common isolates (Table 2). The previous results are
expected due to the common vehicle of microbial
transmission which is the human hands and fingers. Scott
and Bloomfield (2008) suggested that, where conta-
minated surfaces come into even relatively brief contact
with the fingers or an inanimate surface, a significant
number of organisms can be transferred which can be
recoverable onto an agar surface. In our study Gram +ve
bacteria were more frequently isolated from all surfaces
compared to Gram -ve (Figure 1). This could be in part
due to the fact that survival of Gram +ve species on
laminate surfaces is greater than that of Gram negative
organisms (Scott and Bloomfield, 2008). However, both
Gram +ve and Gram -ve bacteria have been shown to
have similar transfer rates from laminate surfaces to
fingertips (Scott and Bloomfield, 2008). Normal skin is
inhabited with two categories of bacteria: transient and
resident. Resident flora, which are attached to deeper
layers of the skin, are more resistant to removal by
routine washing. Coagulase-negative staphylococci and
Gram +ve diphtheroids are members of this group (Boyce
and Pittet, 2002). On the other hand, transient flora
colonizes the superficial layers of the skin, and is more
amenable to removal by routine hand washing (Boyce
and Pittet, 2002). Domestic and public computer key
boards and mice were swabbed and cultured. The
swabbed areas were the keys mostly pressed like the
space bar, the Enter and Backspace buttons. 100% of
Internet café's computers were found to be contaminated
(Table 1). Comparing these results to the home computer
keyboards and mice there is a reduction in the
percentage of contamination to 88 and 91% respectively.
This reduction is expected due to the limited number of
users and assumed continuous cleaning in houses.
Nevertheless a percentage of 88 or 91% is still
considered high. Percentage of contamination of offices’
computer keyboards and mice came in between; this
could be attributed to the higher number of
heterogeneous users, periodic cleaning and dusting of
the office furniture and computers. Most common
Al-Ghamdi et al. 4001
Figure 2. Comparison between isolates from computer keyboards from homes, offices and
Internet cafes.
Figure 3. Comparison between percentage isolates from computer mice from homes, offices
and internet cafes.
contaminating microbes for computer keyboards and
mice were commensal skin organisms followed by some
pathogenic microbes (Figures 2 and 3) however, key
boards and mouse of internet café exhibited the highest
percentage of pathogenic organisms (Figures 2 and 3).
Computer keyboards are one of the most commonly-
touched and shared surfaces today. By inference,
anytime a keyboard is shared among two or more people,
it becomes a risk for the spread of infection (Marsden,
2009). Thus, keyboards have become reservoirs for
pathogens especially in hospitals and schools (Diggs et
al., 2008). One should also note here that a reason for
the increased percentage of contamination of computers
is the difficulty of cleaning and disinfection (Marsden,
2009), as well as the misconception that cleaning
keyboards could possibly damage therm. A possible
solution to the spread of infectious diseases through
keyboard sharing could be by making both cleaning and
disinfection effective and easy (Marsden, 2009).
The occurrence of bacteria on the handles of shopping
carts was detected in four different locations that were
geographically far apart. The percentage of contaminated
4002 Afr. J. Microbiol. Res.
cart handles was almost the same for all locations except
for location 1, yet the observed difference was not
significant (Table 1). People who push the shopping carts
vary in their hygienic status; moreover the items that
shoppers hold in their hands v ary in the degree of
cleanliness. The in-shop handling of different items is
another factor that determines hand hygiene. Fluctuation
between items such as fresh vegetables, fruits and then
fresh dripping chicken, fish or frozen items would subject
the hands to dampness and make them apt for picking up
microbes. Those samples obtained from elevator buttons
of shopping malls and of residential areas revealed
nearly the same percent of contamination as those of
other objects (Table 1). Formerly mentioned transient
flora including potentially pathogenic bacteria such as S.
aureus and Gram negative bacilli can be obtained from
various sources in the environment some of which have
been mentioned earlier such as shopping cart handles,
elevator buttons, and supermarkets. Other sources could
be contaminated surfaces, shaking hands with carriers of
diseases or with patients (Ulger et al., 2009). The hands
of health care workers may become persistently
colonized with such bacteria and consequentially spread
it to others outside the healthcare premises through hand
shaking or through touching various objects such as
shopping carts, elevator buttons or computers.
The potentially pathogenic S. aureus was isolated from
the four tested objects but in lower percentages (Table
2).The ecologic niche for S. aureus in humans is in the
anterior nares (Miller and Diep, 2008). One-quarter to
one-third of healthy persons harbor S. aureus in the nose
at any time (Kluytmans et al., 1997) which can easily be
transferred to hands by simply rubbing the nose. In the
present study one sixth of the isolates were S. aureus
(15±0.02%). This strengthens the possibility of transfer of
potentially pathogenic bacteria through human hands
which could include antibiotic resistant bacteria such as
community associated –MRSA (Miller and Diep, 2008).
Inanimate objects have been known to play a role in
the transmission of human pathogens either directly by
surface to mouth contact or indirectly by contamination of
fingers and subsequent hand to mouth contact (Rusin et
al., 2002). Other routes of exposure include eyes, nose,
and cuts on abraded skin. In the present study four
inanimate objects have been shown to carry non
pathogenic and potentially pathogenic bacteria. Even
when contaminated surfaces containing relatively low
numbers of organisms come into contact with the fingers
and other surfaces, organisms may be transferred in
sufficient numbers to represent a potential infection
hazard (Scott and Bloomfield, 2008). On the other hand,
the capability of pathogenic micro-organisms to exist in
the viable but non-culturable (VBNC) state would pose
risks of being overlooked during isolation. Furthermore,
some investigators claim that non-culturable bacteria of
selected species can be resuscitated to the culturable
state as with Vibrio cholerae O1 that was isolated in the
culturable form from stools of volunteers after ingestion
of VBNC V. cholerae O1 (Colwell et al., 1996). Thus the
use of conventional methods of isolation like those used
in the present study would not necessarily reflect the
actual bacterial contamination status on these objects
and thus the actual microbial load may not have been
elaborated.
As reported by Lowbury and Fox (1953) and
Rathmachers and Borneff (1977) soiling is an important
factor in preserving viability of bacteria on hard surfaces.
Thus dirty surfaces would harbor more bacteria than
clean ones. This makes the process of dusting and
removal of soil and dirt by simple cleaning procedures of
paramount influence on the reduction of surface
contamination. Although drying plays an important part in
maintenance of hygiene on surfaces and other environ-
ments, drying per se cannot be relied upon to prevent
transfer of infection from laminate surfaces due to the
resistance of some microbes to that measure (Scott and
Bloomfield, 2008). Clinical investigations indicate that
infection risks depend on numbers of organisms
transferred and the immune status of the person (Scott
and Bloomfield, 2008). Potentially pathogenic bacteria
isolated from the four objects include Staphylococcus
aureus, Pseudomonas spp. and other Gram -ve bacilli
(Figure 1). These bacteria pose risk to the
immunocompromised and immune suppressed persons.
This study demonstrates that microbial contamination
of computer keyboards, computer mice, shopping carts
and elevator buttons is prevalent and that commensal
skin organisms are the commonest contaminating
microbes. The study also shows that Gram positive
bacteria are transmitted most readily from environmental
surfaces followed by Gram negative bacteria. The
present investigation emphasizes the importance of good
hand hygiene and adequate decontamination procedures
applied to laminate surfaces, computer keyboards, mice
and shopping carts.
With the emergence of global infectious diseases like
Swine flu and SARS a lot of supermarkets have been
implementing measures of hygiene by providing
disinfectants at entry and at several critical contamination
points such as chicken and meat refrigerators. This could
be taken as a step forward to minimize hand contami-
nation. Such approaches should be undertaken in parallel
with community education for hygienic standards,
respiratory etiquette and hand washing. Methods of
decontamination and disinfection of computers, cell
phones and other sensitive electronics should be
elaborated to consumers.
ACKNOWLEDGEMENTS
The authors would like to thank the Faculty of Applied
Medical Sciences at King Abdulaziz University in Jeddah,
Saudi Arabia, for providing the space and facilities for
carrying out this study. Thanks also to Mrs Abrar
Algahtani, Mrs Ruqaih Algasham and Mrs Wed Bajned
for their assistance during this study.
REFERENCES
Boyce JM, Pittet D (2002). Guideline f or Hand Hygiene in Health Care
Settings: recommendations of the Healthcare Infection Control
Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA
Hand Hygiene Task Force. Infect. C ontrol Hospital Epidemiol., 23: 3-
40
Cheesbrough M (2006). District laboratory practice in tropical c ountries.
(Cambridge Univ Pr)
Colwell RR, Brayton P, Herrington D, T all B, Huq A, Levine MM (1996).
Viable but non-culturable Vibrio cholerae O1 revert to a cultivable
state in the human intestine. World J. Microbiol. Biotechnol., 12: 28-
31
Diggs R, Diallo A, Kan H, Glymph C, Furness BW, Chai SJ (2008).
Norovirus outbreak in an elementary school—District of Columbia,
February 2007. C enters for Disease Control and Prevention: Morb.
Mortal. Wkly. Rep., 51: 1340-1343
Kluytmans J, Van Belkum A, Verbrugh H (1997). Nasal carriage of
Staphylococcus aureus: epidemiology, underlying mechanisms, and
associated risks. Clin. Microbiol. Rev., 10: 505-550
Lowbury EJL, Fox J (1953). The influence of atmospheric drying on the
survival of wound flora. J. Hyg., 51: 203-214
Al-Ghamdi et al. 4003
Marsden R (2009). A Solid-Surfaced Inf ection Control Computer
Keyboard. www.cleankeys.nl/whitepaper.pdf, pp. 1-5
Miller LG, Diep BA (2008). Colonization, fomites, and virulence:
rethinking the pathogenesis of community-associated methicillin-
resistant Staphylococcus aureus infection. Clin. Infect. Dis., 46: 752-
760
Noskin GA, Stosor V, Cooper I, Peterson LR (1995). Recovery of
vancomycin-resistant enterococci on fingertips and environmental
surfaces. Infect. Control Hosp. Epidemiol., 16: 577-581
Rathmachers B, Borneff M (1977). Development of a new test method
for surface disinfection procedures IV: Natural drying rates of
microorganisms and their modification by environmental factors.
Zentralblatt fur Bakteriologie, Parasitenkunde, Inf ektionskranheiten
und Hygiene I Abteilung Originale, Reihe B., 165: 43-59
Reynolds KA, W att PM, Boone SA, Gerba CP (2005). Occurrence of
bacteria and biochemical markers on public surfaces. Int. J. E nviron.
Health Res., 15: 225-234
Rusin P, Maxwell S, Gerba C (2002). Comparative surface-to-hand and
fingertip-to-mouth transfer efficiency of gram-positive bacteria, gram-
negative bacteria, and phage. J. Appl. Microbiol., 93: 585-592
Scott E, B loomfield SF (2008). The survival and transfer of microbial
contamination via cloths, hands and utensils. J. Appl. Microbiol., 68:
271-278
Ulger F, Esen S, Dilek A, Yanik K, Gunaydin M, Leblebicioglu H (2009).
Are we aware how contaminated our mobile phones with nosocomial
pathogens? Annals Clin. Microbiol. Antimicrob. 8: 7.
... Contamination of environmental objects and surfaces is a common phenomenon, most people don't realize the microbes, are found on many common objects include playground equipment, kitchen, sinks, office desks, computer keyboards, escalator handrails, elevator bottom and with the spread of supermarkets, all of the latter objects are places that are most touched by the bare hands of people who are in various hygienic conditions [2]. ...
... The computer equipment may acts as a reservoir for the transmission of potential hazardous or pathogenic microorganisms. The ability of a computer to act as fomites has been previously documented in health care on hospital environment [5] .In fact 80 % of infections are spread throughout hand contact with hands or other objects the viability of Gram positive and some Gram negative organisms under various environmental conditions have been found to survive in dry conditions and on various fabrics utilized in the health care environment [2]. ...
... In our study Gram positive bacilli bacteria were more frequently (90.8) % (X 2 =4.9, P<0.05) and Gram negative bacilli (80.4) isolated from all surfaces computers (X 2 =6.2 , P<0.05) , this could be in part due to the fact that survival of Gram positive spores on laminate surfaces is great than that of Gram negative organisms (4,2,17). ...
Bacterial contamination of computer keyboards and mouse
Article
Full-text available
  • Feb 2022
A study was carried out to isolate and identify microorganism associated with computer keyboards and mice. A total of (250) samples were collected from two different objects (150) samples from the keyboards and (100) samples from the mice. Samples were collected from different Computer centers places some computer laboratories (multiple-user) in college of medicine, Al-Batol Teaching Hospital, Al-Jamhory Teaching Hospital in Mosul City and Laptops of Single-user (staff rooms).The collected samples were inoculated on Nutrient agar,, Salmonella-Shighella agar, Blood agar, Chogulate agar ,Maconkey agar ,Brucella agar and Minnitol Salt agar .The isolates obtained were examined and identified by colonial morphology; biochemical characteristics and Gram stain, 99.2% of total samples collected were contaminated with mixed bacterial growth. The bacteria that have been isolates includes, Gram positive bacilli,Gram negative bacilli, Staphylococcus aureus , Staphylococcus epidermis ,Enterococcus, Escherichia coli, Streptococcus.The study indicated that the number of microorganisms present on multiple-user computer keyboard and mice were greater than the single user computer keyboards and mice. The presence of pathogenic and commercial bacteria on the computer keyboards and mice indicates that they might acts as environmental vehicles for the transmission of potentially pathogenic bacteria. Our data recommended that regular cleaning and disinfection of the different parts of computers must be used to reduce the microbial load especially for multiple user work station. Aims of the study This study aims to identify the types of bacteria which could be the source of contamination from computer keyboards and mouse to the users. 2
... Contamination of environmental objects and surfaces is a common phenomenon, most people don't realize the microbes, are found on many common objects include playground equipment, kitchen, sinks, office desks, computer keyboards, escalator handrails, elevator bottom and with the spread of supermarkets, all of the latter objects are places that are most touched by the bare hands of people who are in various hygienic conditions [2]. ...
... The computer equipment may acts as a reservoir for the transmission of potential hazardous or pathogenic microorganisms. The ability of a computer to act as fomites has been previously documented in health care on hospital environment [5] .In fact 80 % of infections are spread throughout hand contact with hands or other objects the viability of Gram positive and some Gram negative organisms under various environmental conditions have been found to survive in dry conditions and on various fabrics utilized in the health care environment [2]. ...
... In our study Gram positive bacilli bacteria were more frequently (90.8) % (X 2 =4.9, P<0.05) and Gram negative bacilli (80.4) isolated from all surfaces computers (X 2 =6.2 , P<0.05) , this could be in part due to the fact that survival of Gram positive spores on laminate surfaces is great than that of Gram negative organisms (4,2,17). ...
Histological changes of mice testis infected with trichomonas vaginalis in vivo
Article
Full-text available
  • Dec 2010
This study concerned with the effect of trichomonas vaginalis parasute on the histology of mice testis The parasite was taken from the vaginal swap of female albatooo hospital and inoculated of the parasite in the mice after 15days the testis was taken showed many histological changes while there was no changes in the testis of control group
... It is well known that objects undergoing constant human interaction are colonized by many different strains of bacteria [1,14,19,22]. These bacteria can include potential pathogens or indicator bacteria such as fecal coliforms, which have been detected in 7% of objects sampled from locations such as shopping centers, daycares, offices, playgrounds, and movie theatres [19]. ...
... Items that are touched by humans are even more contaminated. For example, 97% of elevator buttons in residential and commercial buildings were found to be contaminated with mixed bacterial growth [1]. Chief among the bacterial isolates obtained were coagulase-negative staphylococci, Gram-positive bacilli, and pathogens including Staphylococcus aureus, Pseudomonas spp., and various Gram-negative bacteria [1]. ...
... For example, 97% of elevator buttons in residential and commercial buildings were found to be contaminated with mixed bacterial growth [1]. Chief among the bacterial isolates obtained were coagulase-negative staphylococci, Gram-positive bacilli, and pathogens including Staphylococcus aureus, Pseudomonas spp., and various Gram-negative bacteria [1]. Bacteria from objects can be transferred to people's hands and detected in their home or on personal belongings hours later [19]. ...
Bacterial Load of Virtual Reality Headsets
Conference Paper
Full-text available
  • Aug 2020
As commodity virtual reality (VR) systems become more common, they are rapidly gaining popularity for entertainment, education, and training purposes. VR utilizes headsets which come in contact with or close proximity to the user's eyes, nose, and forehead. In this study, the potential for these headsets to become contaminated with bacteria was analyzed. The nosepieces and foreheads of two HTC Vive headsets were sampled over the course of a seven-week period in a VR software development course. Serial dilutions were performed, and samples were plated on various culture media. Following incubation, counts of bacteria were determined. DNA was extracted from bacterial colonies and the 16S rRNA gene was sequenced to identify bacterial contaminates present on the headsets. Chief among these contaminates was Staphylococcus aureus. The results of these tests indicated that the Staphylococcus aureus strains isolated from the headsets possessed high levels of antibiotic resistance. Other notable bacterial isolates included Moraxella osloensis, the bacteria responsible for foul odors in laundry and Micrococcus luteus, a communalistic bacterial species capable of causing opportunistic infections. Other bacterial isolates were detected in variable amounts throughout the trial.
... The results of the current study reveals that solid surfaces are colonized by viable organisms and people using them can act as carriers. These findings are in agreement with the results obtained in previous studies [16,17] where they isolated pathogenic bacteria from elevator buttons and concluded that elevators are actually contaminated with potential pathogens. Al-Ghamdi et al 2011 [16] reported the highest contamination rate of elevator buttons (97%) and our study confirms that elevator buttons are heavily contaminated with rate of less than 40% ( fig. 1). ...
... These findings are in agreement with the results obtained in previous studies [16,17] where they isolated pathogenic bacteria from elevator buttons and concluded that elevators are actually contaminated with potential pathogens. Al-Ghamdi et al 2011 [16] reported the highest contamination rate of elevator buttons (97%) and our study confirms that elevator buttons are heavily contaminated with rate of less than 40% ( fig. 1). The difference could be attributed to the less number of elevators that were included in our study while Al-Ghamdi et al. included residential and shopping mall elevators. ...
Elevators and staircase handrails as potential sources of nosocomial pathogens at Ndola Teaching Hospital, Zambia
Preprint
Full-text available
  • Nov 2021
This study aimed to assess microbial colonization of elevators and the staircase handrail at Ndola Teaching Hospital. Swabs from elevators and staircase handrail were cultured on Blood, MacConkey and Mannitol Salt agar for 24-48h at 35-37 o C. All observed bacterial colonies were sub-cultured for identification. Data analysis was conducted with Microsoft excel 2010 and SPSS version 20 statistical software. A 2-tailed Pearson Correlation test was used to assess for significant differences in colonization prevalence between the two elevators and handrail. A total of 94 bacteria species were isolated, among which 75(78.8%) were isolated from elevators while 19(20.2%) were isolated from the staircase handrail. Most bacteria were isolated from exterior buttons followed by doors and interior of elevators whereas the basement, ground and sixth floor sections of the staircase handrail were largely contaminated with S. aureus, non-spore-forming Gram-positive bacilli, Klebsiella spp, coagulase-negative Staphylococci and Enterobacter spp. Overall, the commonest isolated bacteria were S. aureus (33%) followed by non-spore-forming Gram-positive bacilli (16%), coagulase-negative Staphylococci, and endospore-forming Gram-positive bacilli (13.8% apiece), Streptococci (7.4%), and Klebsiella species (6.4%). A strong relationship existed between the prevalence of bacteria colonizers of elevators and the staircase handrail (p<0.01). Therefore, the study showed that elevators and the staircase handrail possess viable microorganisms and may act as potential sources of nosocomial infections especially to immunocompromised patients in hospitals, and this calls for proper and effective infection control and prevention strategies to lessen microbial population from dry surfaces.
... A 2011 study collected 400 samples in various public settings (offices, homes, supermarkets, etc.) and reported robust bacterial colonies on common everyday surfaces [5]. The article noted the necessity for a gentle cleaning solution that would not damage surfaces, keyboards, or computers [3]. ...
Bactericidal and Fungicidal Efficacy of Chlorine Dioxide in Various Workspaces
Article
Full-text available
  • Jan 2022
... According to the World Health Organization (WHO), infections associated with microorganisms cause death to over 17 million people worldwide every year [1]. Around 80% of these microorganisms are transferred from the non-sanitized human hands to food, objects, or people thus contributing to communicable diseases [2]. Public sanitation and hand hygiene are universally recognized by the Centers for Disease Control and Prevention, the World Health Organization, and many other health experts as one of the most effective phenomena in disease prevention [3]. ...
Antimicrobial Assessment of a Novel Humectant-Hand-Sanitizer against Microbes Transferred To Human Palms from Mobile Phones With/Without Flip Covers
Article
Full-text available
  • Jan 2022
The lack of proper sanitation and hygiene over the years has contributed to a rapid increase in communicable diseases, especially in developing nations like India. This problem warrants investigation of the potential routes responsible for transmitting microbes and infections to an individual. In this study, we have assessed bacterial and fungal load in covered (with flip covers) and uncovered (without flip covers) mobile phones, and the potential transfer of these microbes from phone surfaces to human palm surfaces. The bacterial load (in cfu) in mobile phones with flip covers was 13-fold higher than that of the uncovered phones meanwhile, the fungal load was relatively higher in the uncovered phones. The transfer of bacterial population (in cfu) from the covered mobile phones to the palm surfaces was 14.5-fold higher than that of the uncovered phones. Similarly, fungal transfer was relatively higher from the uncovered phones to the palm surfaces. We further developed a novel alcohol-based Humectant-Hand-Sanitizer (HH-sanitizer) and its sanitization efficiency (in %) was compared with one of the most popular Hygiene products in India, Dettol, against microbes obtained from human palm surfaces (before and after rubbing over mobile phones), and a group of opportunistic pathogens: Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Enterococcus sp., Bacillus cereus, Listeria monocytogenes, Candida albicans, and Aspergillus sp. The sanitization efficiency (SE %) of the HH-sanitizer on palm surfaces was 98.78±1.82% and 91.27±4.24% against bacterial and fungal isolates respectively, whereas the SE % for the Dettol sanitizer was 94.62% against bacteria and 45.89% against fungi. In vitro antimicrobial assessment against the tested organisms showed the minimum inhibitory concentration of the HH-sanitizer to be 8-fold lower than the Dettol sanitizer. Thus, the HH-sanitizer has the potentiality to be an alternative option. Since bacterial adherence to mobile phones with flip covers and their transfer to human hands was significantly higher and as the common infections, we are prone to are caused more by bacteria than fungus, either way, avoidance of flip covers in phones/laptops/tablets, etc. is recommended to avoid transmittable infections and achieve better hygiene.
... Several studies have shown that cell phones contaminated with pathogenic bacteria play a big role in the spread of infectious disease (Brady et al., 2006;Tagoe et al., 2011). Many users do not generally know the microbial load on many regular objects within their living and workplaces (Al-Ghamdi et al., 2011;Shalinimol, 2016). The unclean ways of handling such objects make them a cardinal reservoir of an assembly of pathogenic microorganisms (Zakai et al., 2016;Adhikari et al., 2018) thus mobile cell phones surfaces might serve as fomites in the transmission of these microbes (Bhoonderowa et al., 2014). ...
Bacterial Contamination Associated with Mobile Cell Phones among Undergraduate Students of Federal University of Lafia, Nasarawa State, Nigeria
Article
  • Apr 2021
Mobile cell phones are extensively used globally. This study was aimed at determining bacterial contamination associated with mobile cell phones among undergraduate students of Federal University of Lafia, Nasarawa State, Nigeria. One hundred swab samples from mobile cell phones were randomly collected from the students’ cell phones between August 2019 and December 2019. Demographic factors like age, gender, mobile phone type, storing of mobile cell phones, cleaning habits and use in toilets were collected using a semi-structured questionnaire. The samples were analysed using standard microbiological techniques. The data collected were analysed using percentile and SPSS version 20.0. The value (p<0.01) was statistically considered to have significant associations. Microbial analysis showed that 70 nondisinfected samples were contaminated by eight diverse types of bacteria, which included Escherichia sp., Salmonella sp., Bacillus sp., Pseudomonas sp., Staphylococcus sp., Klebsiella sp., Micrococcus sp and Enterobacter sp. The swabbed cell phones of females (56.3%) were more contaminated than those of males (43.7%) with bacterial load count of 41.9 x 103 and 28.8 x 103 CFU/mL among females and males, respectively. The mobile cell phones used in toilets (75.0%) were highly contaminated by bacteria. Users who did not cut their nails had higher contamination (69.4%) than those users who cut their nails (34.3; p = 0.01). The age of mobile cell phones within 6 – 12 months had 55.5% for females and 23.5% for males. This study showed that mobile cell phones harbor bacteria liable for causing health threats to handlers. Therefore, awareness programs concerning hand hygiene and discouraging their use in toilets to avoid causing severe health consequences. The use of disinfectants to wipe mobile cell phones whenever contamination is encountered is advocated to safeguard public health. Keywords: Mobile Cell Phone, Swabs, Microbes, Contamination
... Listeria monocytogenes has a high prevalence in produce retail establishments and could potentially cross contaminate produce (10,48). The contamination of produce in grocery stores can result from contaminated display shelves, contaminated shopping carts (3), moist conditions that encourage pathogens' growth and survival (19), and handling by consumers and store workers (37). Food retail stores are required to have a written pest management plan to protect the safety of food (47), as the literature reports that the presence of pests, such as cockroaches, flies, and mice, could potentially carry human pathogens and crosscontaminate foods (11,32). ...
Determining the Potential Food Safety Risks Associated with Dropped Produce on Floor Surfaces in Grocery Stores
Article
Grocery stores handle fresh produce in large quantities daily. According to the Food and Drug Administration Food Code, food is to be stored at least 15 cm above the floor, and all foods shall be protected from any source of contamination or otherwise discarded. It is reported in the literature that dropped produce could be a potential source of microbial contamination. Both consumers and employees often drop produce on the floor and then place it back into a display case or bin, which could potentially serve as a source of contamination. This study aims to determine the bacterial transfer rate on different produce types when dropped for various contact times onto floor surfaces contaminated with Listeria monocytogenes. Apples, peaches, and romaine lettuce were dropped separately onto carpet and tile surfaces from a distance of 1 m and held for 5 s, 1 min, 10 min, 1 h, and 4 h. Results showed that transfer from all produce types occurred from both the carpet (10.56%) and tile (3.65%) surfaces. Still, percent transfer was not statistically significant among different times used in this study (P > 0.05). Dropped romaine lettuce had the most transfer (28.97%) from both the surfaces combined, followed by apples (8.80%) and peaches (7.32%) with minimal transfer. Even with a low transfer level, grocery stores should include signage to alert consumers not to pick up dropped produce and should train their employees accordingly. HIGHLIGHTS
Assessment of Computer Keyboards for bacterial contamination Assessment of computer keyboards at the Lagos State University for bacterial contamination
Article
Full-text available
  • Jan 2020
Elevating Haptics: An Accessible and Contactless Elevator Concept with Tactile Mid-Air Controls
Conference Paper
  • May 2021
Are we aware how contaminated our mobile phones with nosocomial pathogens?
Article
Full-text available
  • Feb 2009
The objective of this study was to determine the contamination rate of the healthcare workers' (HCWs') mobile phones and hands in operating room and ICU. Microorganisms from HCWs' hands could be transferred to the surfaces of the mobile phones during their use. 200 HCWs were screened; samples from the hands of 200 participants and 200 mobile phones were cultured. In total, 94.5% of phones demonstrated evidence of bacterial contamination with different types of bacteria. The gram negative strains were isolated from mobile phones of 31.3% and the ceftazidime resistant strains from the hands were 39.5%. S. aureus strains isolated from mobile phones of 52% and those strains isolated from hands of 37.7% were methicillin resistant. Distributions of the isolated microorganisms from mobile phones were similar to hands isolates. Some mobile phones were contaminated with nosocomial important pathogens. These results showed that HCWs' hands and their mobile phones were contaminated with various types of microorganisms. Mobile phones used by HCWs in daily practice may be a source of nosocomial infections in hospitals.
Recovery of Vancomycin-Resistant Enterococci on Fingertips and Environmental Surfaces
Article
Full-text available
  • Nov 1995
To determine the recovery of vancomycin-resistant enterococci (VRE) on fingertips, gloved fingertips, and environmental surfaces commonly encountered in the healthcare setting, and to examine the importance of handwashing on the removal of these organisms. Two clinical isolates of VRE (Enterococcus faecalis and Enterococcus faecium) were inoculated onto the hands of healthy human volunteers and the following environmental surfaces: countertops, bedrails, telephones, and stethoscopes. Following inoculation, samples were obtained at various time intervals to determine rates of recovery of organisms. To evaluate the effects of handwashing on enterococcal recovery, two different soap preparations were tested. Hands were washed with water alone or with one of the soaps and water. The soap and water studies were performed with a 5-second and a 30-second wash. Both enterococcal strains survived for at least 60 minutes on gloved and ungloved fingertips. The E faecalis was recoverable from countertops for 5 days; the E faecium persisted for 7 days. For bedrails, both enterococcal species survived for 24 hours without significant reduction in colony counts. The bacteria persisted for 60 minutes on the telephone handpiece and for 30 minutes on the diaphragmatic surface of the stethoscope. A 5-second wash with water alone resulted in virtually no change in recovery of enterococci; a 30-second wash with water plus either soap was necessary to eradicate the bacteria from hands completely. VRE are capable of prolonged survival on hands, gloves, and environmental surfaces. Hands should be washed thoroughly and gloves removed following contact with patients infected or colonized with these multidrug-resistant bacteria. Finally, environmental surfaces may serve as potential reservoirs for nosocomial transmission of VRE and need to be considered when formulating institutional infection control policies.
Nasal Carriage of Staphylococcus aureus: Epidemiology, Underlying Mechanisms, and Associated Risks
Article
Full-text available
  • Aug 1997
Staphylococcus aureus has long been recognized as an important pathogen in human disease. Due to an increasing number of infections caused by methicillin-resistant S. aureus (MRSA) strains, therapy has become problematic. Therefore, prevention of staphylococcal infections has become more important. Carriage of S. aureus appears to play a key role in the epidemiology and pathogenesis of infection. The ecological niches of S. aureus are the anterior nares. In healthy subjects, over time, three patterns of carriage can be distinguished: about 20% of people are persistent carriers, 60% are intermittent carriers, and approximately 20% almost never carry S. aureus. The molecular basis of the carrier state remains to be elucidated. In patients who repeatedly puncture the skin (e.g., hemodialysis or continuous ambulatory peritoneal dialysis [CAPD] patients and intravenous drug addicts) and patients with human immunodeficiency virus (HIV) infection, increased carriage rates are found. Carriage has been identified as an important risk factor for infection in patients undergoing surgery, those on hemodialysis or CAPD, those with HIV infection and AIDS, those with intravascular devices, and those colonized with MRSA. Elimination of carriage has been found to reduce the infection rates in surgical patients and those on hemodialysis and CAPD. Elimination of carriage appears to be an attractive preventive strategy in patients at risk. Further studies are needed to optimize this strategy and to define the groups at risk.
District Laboratory Practice in Tropical Countries
Article
  • Jan 1998
Changes in the organization of health services in developing countries have led to district levels assuming more responsibility for the planning, delivery and quality of community health care. This fully up-dated new edition has been produced to help those working in the district laboratory, and those responsible for the organization and management of community laboratory services and the training of district laboratory personnel. Replacing the previous publication Medical Laboratory Manual for Tropical Countries, this book provides an up-to-date practical bench manual, taking a modern approach to the provision of a quality medical laboratory service. Reviews: Review of District Laboratory Practice in Developing Countries Part 1: 'Clear and easily understood information is provided on the clinical biochemistry of laboratory analytes and the biology of parasites … The book is probably the most comprehensive source of information available today to those who work in or need to know about laboratory services in developing countries. It can be recommended as a basic document for laboratory technicians, technologists, and medical doctors at all levels …' Bulletin of the World Health Organization.
Norovirus outbreak in an elementary school - District of Columbia, February 2007
Article
  • Feb 2008
Solid-Surfaced Infection-Control Keyboard A Solid-Surfaced Infection Control Computer Keyboard
Article
The computer keyboard has become one of the leading causes of the spread of infectious disease in healthcare settings, schools, and anywhere keyboards are shared. It has become apparent that care must be taken to clean and disinfect keyboards regularly. A variety of cleanable keyboard solutions are compared for the criteria of: speed of cleaning, ease of cleaning, effectiveness of infection control, aesthetic qualities, usability, and durability. The approach using a solid, touch-sensitive surface was found to be the highest rated over these categories. Features such as tactile key-wells and integrated tap sensors significantly enhance the usability of this type of keyboard, making it ideally suited for infection control environments.
Viable but non-culturable Vibrio cholerae O1 revert to a cultivable state in the human intestine
Article
  • Jan 1996
Vibrio cholerae O1 can enter a state in which they remain viable but are non-culturable. Presumably, such bacteria can be pathogenic if they retain the capacity to proliferate in the human intestine following ingestion. Two groups of volunteeers were given inocula containing viable but non-culturable V. cholerae O1 of the attenuated vaccine strain CVD 101 (viable CVD 101 organisms readily colonize the human intestine). Volunteers in one of the two groups excreted viable CVD 101, demonstrating that, in the environment of the human intestine, previously non-culturable vibrios can regain the capacity to multiply. These observations support the proposition that viable but non-culturable bacterial enteropathogens may pose a potential threat to health.
[Development of a new testmethod for surface disinfection procedures. IV. Natural bacterial dying rates and their modification by environmental influences (author's transl)]
Article
  • Oct 1977
The Survival and transfer of microbial contamination via cloths, hands and utensils
Article
Survival and transfer of bacteria from laminated surfaces and cleaning cloths were investigated under laboratory conditions. Drying produced substantial reductions in numbers of recoverable organisms and achieved satisfactory decontamination of clean laminate surfaces. On soiled surfaces and on clean and soiled cloths, Gram-positive and some Gram-negative species survived for up to 4 h, and in some cases up to 24 h. Where contaminated surfaces or cloths came into contact with the fingers, a stainless steel bowl, or a clean laminate surface, organisms were transferred in sufficient numbers to represent a potential hazard if in contact with food.
Comparative surface-to-hand and fingertip-to-mouth transfer efficiency of Gram-positive bacteria, Gram-negative bacteria, and phage
Article
  • Oct 2002
To determine the transfer efficiency of micro-organisms from fomites to hands and the subsequent transfer from the fingertip to the lip. Volunteers hands were sampled after the normal usage of fomites seeded with a pooled culture of a Gram-positive bacterium (Micrococcus luteus), a Gram-negative bacterium (Serratia rubidea) and phage PRD-1 (Period A). Activities included wringing out a dishcloth/sponge, turning on/off a kitchen faucet, cutting up a carrot, making hamburger patties, holding a phone receiver, and removing laundry from the washing machine. Transfer efficiencies were 38.47% to 65.80% and 27.59% to 40.03% for the phone receiver and faucet, respectively. Transfer efficiencies from porous fomites were <0.01%. In most cases, M.luteus was transferred most efficiently, followed by phage PRD-1 and S. rubidea. When the volunteers' fingertips were inoculated with the pooled organisms and held to the lip area (Period B), transfer rates of 40.99%, 33.97%, and 33.90% occurred with M. luteus, S. rubidea, and PRD-1, respectively. The highest bacteral transfer rates from fomites to the hands were seen with the hard, non-porous surfaces. Even with low transfer rates, the numbers of bacteria transferred to the hands were still high (up to 10(6) cells). Transfer of bacteria from the fingertip to the lip is similar to that observed from hard surfaces to hands. Infectious doses of pathogens may be transferred to the mouth after handling an everyday contaminated household object.