Available at State Public Health Laboratory (Karnal) 1 , Pt. BD

Full text

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 406
Research Publish Journals
Effect of Carbapenems on Clinical Isolates of
Acinetobacter baumannii spp. in Tertiary Care
Hospital of North India
Ravi Kumar1, Nidhi Goel2, Yogesh Kumar3, Uma Chaudhary4
State Public Health Laboratory (Karnal)1, Pt. BD. Sharma University of Health Science (Rohtak)2,4, KCGMC (Karnal)3
(INDIA)
Abstract: A. baumannii has been designated as a “red alert” human pathogen, generating among the medical
fraternity, arising largely from its extensive antibiotic resistance spectrum. Carbapenem resistance in
Acinetobacter is now observed increasingly, and constitutes a sentinel event for emerging antimicrobial resistance.
The production of carbapenem hydrolyzing beta-lactamases is the most common mechanism responsible for
carbapenem resistance. Design: This prospective study was conducted in the Department of Microbiology, Pt. B.D.
Sharma PGIMS, Rohtak from December 2012-November 2013, on 100 isolates of Acinetobacter baumannii. The
specimens were process for bacteriological cultures, biochemical reactions and antigenic sensitivity against
Antibiotic [Imipenem, Meropenem and Doripenem (Carbapenem group)] by kirby-bauer method. P value <0.05
was statistically significant. Results: Out of 42141 samples 855 (7.75%) specimen shows A. baumannii growth.
Male to female ratio was 1.70:1. Patients belonged to age 51-60 years (29%) and 76% with ICU. The endo-tracheal
aspirate isolates were 66%. Isolates were sensitive to Carbapenem group followed by imipenem (81%),
Meropenem (39%) and doripenem (40%). On comparing the resistance to carbapenems P value were significant in
imipenem, meropenem and Doripenem, i.e. <0.05. Conclusion: Treatment of Acinetobacter infection should be
prescribed on the basis of antimicrobial sensitivity reports and judicious way to decrease the emergence of drug
resistant isolate. Sharing of expertise and collaboration between the clinicians using antibiotic therapy and
microbiologist may be the simplest health measure to optimise the use of antibiotics.
Keywords: Carbapenems, Acinetobacter baumannii, ICU, UTI, BAL, ETA, ET, Lower respiratory tract sample.
1. INTRODUCTION
During the last three decades, outbreaks of infections caused by Acinetobacter spp. have capable of causing a broad range
of clinical disease syndrome especially in critically ill patients with recent intensive care unit stay, surgical procedure or
long hospitalization. Acinetobacter baumannii is a gram-negative, non-fermenting, oxidase-negative and non-motile
cocco-bacillus, it can survive in water, soil, surface of skin and hospital environment, so that causes a series of
opportunistic infections such as, ventilator associated pneumonia (VAP), skin and soft tissue infections, surgical site
infections, bactermia, meningitis, urinary tract infections and septicemia in immuno-compromised patients.1
A. baumannii accounts for as many as 10% of all infections caused by gram-negative bacteria seen in intensive care units
(ICUs), and in the United States, it accounts for only 2.5% infections. Additionally, A. baumannii is now days recognized
as an important cause of community-acquired pneumonia, with a high mortality rate of 40% to 64%. About 3 to 5 % of
nosocomial pneumonias are caused by Acinetobacter spp.2 In large surveillance studies from the United States, between 5
and 10% of cases of ICU-acquired pneumonia were due to A. baumannii.3 A. baumannii is an occasional cause of UTI,
being responsible for just 1.6% of ICU-acquired UTIs in one study.4 And also small number of case reports of
Acinetobacter endocarditis exist.5 In recent years, A. baumannii has been designated as a ―red alert‖ human pathogen,
generating alarm among the medical fraternity, arising largely from its extensive antibiotic resistance spectrum. The

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 407
Research Publish Journals
mechanism of resistance generally falls into three categories, antimicrobial inactivating enzymes, reduced access to
bacterial targets and efflux pump mechanism.
The whole genome sequencing of Acinetobacter baumannii clinical strains led to identification of 86kb resistance is land
known as AbaR1. Overall 52 resistance genes were identified and 45 (86.5%) of them were localized to AbaR1 island.6
The increasing trend of carbapenem resistance in Acinetobacter baumannii worldwide is a concern since it limits the
choice of antimicrobials for the treatment of Acinetobacter baumannii. Metallo-β-lactamases (VIM, IMP, SIM) have been
reported worldwide, especially in Asia and Western Europe, and confer resistance to all β-lactams except aztreonam. The
most widespread β-lactamases with carbapenemase activity in A. baumannii are carbapenem-hydrolysing class D β-
lactamases (CHDLs) that are mostly specific for A. bauamnnii. These enzymes belong to three unrelated groups of
clavulanic acid-resistant b-lactamases, represented by OXA-23, OXA-24 and OXA-58, that can be either plasmid- or
chromosomally encoded. A. baumannii also possesses an intrinsic carbapenem-hydrolysing oxacillinase, the expression of
which may vary, that may play a role in carbapenem resistance. In addition to b-lactamases, carbapenem resistance in A.
baumannii may also result from porin or penicillin-binding protein modifications. Several porins, including the 33-kDa
CarO protein, that constitute a pore channel for influx of carbapenems, might be involved in carbapenem resistance.7
Carbapenem-resistant isolates of A. baumannii are usually resistant to all classes of antimicrobials, and show intermediate
resistance to rifampin, while usually retaining susceptibility to tigecycline and colistin.8 Resistance against carbapenems
is, in itself, considered sufficient to define an isolate of A. baumannii as highly resistant. The resistance of A. baumannii
to carbapenems can be mediated by one of the resistance mechanisms that are known to occur in bacteria, including
enzymatic inactivation, active efflux of drugs, and modification of target sites.7 The production of carbapenem
hydrolyzing beta-lactamases is the most common mechanism responsible for carbapenem resistance in A. baumannii.
Several carbapenem-hydrolyzing β-lactamases have been identified so far in A. baumannii.
Aims and Objectives
To study the Effect of Carbapenems on 100 Clinical Isolates of Acinetobacter baumannii spp. in Tertiary Care Hospital at
North India.
2. MATERIAL AND METHOD
The present prospective study was conducted in the Department of Microbiology, Pt. B.D. Sharma PGIMS, Rohtak over a
period of one year (December 2012 - November 2013). A total of 100 isolates of Acinetobacter baumannii were obtained
from various clinical samples received in Microbiology laboratory from outdoor and indoor patients of the hospital,
irrespective of age and sex. The samples included urine, sputum, pus, blood, endo-tracheal aspirates and broncho-alveolar
lavage (BAL) and process for the bacteriological cultures. The bacterial isolated were identified using standard methods.
After incubation, non-lactose fermenting colonies on MacConkey agar were further processed for identification of
Acinetobacter baumannii.
The various biochemical reactions were used, as indole test, urease test, citrate test, triple sugar iron. And antigenic
sensitivity was measured against Antibiotic [Imipenem, Meropenem and Doripenem (Carbapenem group)] by kirby-bauer
method of 100 isolates and takes the results.
Statistical Analysis:
Collected data was entered in MS Excel spreadsheet and coded appropriately in SPSS (Statistical Package for Social
Studies) for Windows version 20.0. All tests were performed at 5% level significance, thus an association was significant
if the value was less than 0.05 (p value< 0.05).
3. RESULTS
The present study was conducted in the Department of Microbiology, Pt. B. D. Sharma Post Graduate Institute of Medical
Sciences, Rohtak over a period of one year. A total of 100 A. baumannii, isolated from various clinical samples were
included in the present study. A. baumannii isolates identified on the basis of Gram staining, motility and biochemical
reactions were further confirmed by automated BD phoenix system. Antimicrobial susceptibility testing of 100 clinical
isolates of A. baumannii against three drugs was done by using Kirby-bauers disk diffusion method as per CLSI
guidelines. The following observations were made:

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 408
Research Publish Journals
From December 2012 to November 2013, 42141 clinical samples received in the laboratory during the study period,
11028 (26.16%) showed bacterial growth, while rest 31113 samples (73.83%) were either culture sterile, or showed the
growth of bacterial contaminants or fungal isolates. Total no of A. baumannii isolated in study period was 855, so the
overall isolation rate of Acinetobacter baumannii was 7.75%. out of 855 positive specimen, male to female ratio was
1.70:1. Majority of the patients belonged to age groups 51-60 years (29%), followed by 21-30 (29%), 31-40 (12%), 11-
20 (12%) and only 10% belongs than <10 years. The p value was significant in age group 21-30 years.
TABLE 1: Distribution of 885 A. baumannii among different clinical samples
Name of
specimen
Total culture
positive samples
A. baumannii isolated
Number (n)
Percentage (%)
Pus
1290
118
9.14
Blood
4477
415
9.26
LRTS
1550
268
17.29
Sputum
834
24
2.87
Urine
2877
30
1.04
Total
11028
855
7.75%
LRTS- Lower Respiratory Tract Samples,
Among the culture positive samples, maximum rate of isolation of A. baumannii was from lower respiratory tract samples
(17.29%) followed by blood (9.26%), pus (9.14%), sputum (2.87%) & urine (1.04%)
TABLE 2: Distribution of 100 isolates of A. baumannii among various clinical samples
Name of sample
Number of A.
baumannii isolates(n)
Percentage (%) of A.
baumannii isolates
Urine
4
4
Pus
10
10
Blood
9
9
Sputum
3
3
BAL
1
1
Endo-tracheal tip
7
7
Endo-tracheal Aspirate
66
66
Total
100
100.0
The maximum number of A. baumannii were isolated from endo-tracheal aspirate (66%), followed by pus samples
(10%), blood samples (9%), ET Tip (7%), urine (4%).
TABLE 3: Distribution of A. baumannii isolates among patients admitted to ICU and Ward
Name of sample
Ward
ICU
Total
P value
N
%
N
%
n
%
-
Urine
4
16.66
-
-
4
4
-
Pus
10
41.66
-
-
10
10
-
Blood
2
8.3
7
9.21
9
9
0.096
Sputum
3
12.5
-
-
3
3
-
BAL
0
0
1
1.31
1
1
-
Endo-tracheal
1
4.16
6
7.89
7
7
0.059
Endo-tracheal
Aspirate
4
16.66
62
81.57
66
66
<0.001
Total
24
24.0
76
76.0
100
100.0
-

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 409
Research Publish Journals
A. baumannii recovered from indoor patients among various samples, these indoor patients were further classified into
ICU and wards. It was observed that the infections caused by A. baumannii were commonest in the ICU patients 76
(76%). Among the ICU patients, maximum numbers of A. baumannii isolates were recovered from endo-tracheal aspirate
(81.57%), followed by blood (9.21%). Among ward patients maximum number of A. baumannii were recovered from pus
(41.66%), ETA (16.66%), urine (16.66%). On comparing the distribution of A. baumannii isolates among ICU and ward
significant difference in terms of P value was observed in Endo-tracheal aspirate.
TABLE 4: Antimicrobial resistance pattern of clinical isolates of A. baumannii against 22 drugs
Drugs
No. of resistant
isolates (n)
No. of sensitive
isolates (%)
P-value
Carbapenems
Imipenem
19(19%)
81(81%)
<0.01
Meropenem
61(61%)
39(39%)
<0.028
Doripenem
60(60%)
40(40%)
<0.046
On comparing the resistance to carbapenems P value were significant in imipenem, meropenem and Doripenem, i.e.
<0.05.
4. DISCUSSION
The present study was carried out in the Department of Microbiology, Pt. B.D Sharma PGIMS, Rohtak to identify and
perform antimicrobial susceptibility of 100 A. baumannii strains isolated from various clinical specimens, and the Effect
of Carbapenems of all 100 clinical isolates of Acinetobacter baumannii spp.
In the present study, the rate of isolation of A. baumannii from culture positive specimens was 7.75 % which was lower
than the study by Jaggi et al5 who reported an isolation rate of 9.4% from all culture positive samples. However Siau H et
al9 reported the prevalence rate of 11% from the culture positive samples. Lahiri et al10 reported isolation rate of 12.9%
from all culture positive samples. In our study maximum rate of isolation of A. baumannii was from lower respiratory
tract samples 17.29%, pus 9.14%, blood 9.26%, followed by urine 1.04%, sputum 2.87%. The results of current study
were in accordance with Jaggi et al5 who observed maximum rate of isolation of A. baumannii from lower respiratory
samples 56.9%, blood 25.2%, pus 10%, while Prashanth et al11 reported the distribution of A. baumannii isolates among
blood, respiratory samples, and urine samples to be 16.27%, 48.8%, 9.3%. Various authors have reported different
distribution pattern of Acinetobacter isolates among various samples. The present study showed 9% isolation of A.
baumannii from blood samples, which was in accordance with the study by Lahiri et al10 done in ICU patients. Other
studies have reported more or less isolates from blood samples, ranging from 46.7% as reported by Saleem et al12 to 0.9 %
by Liling et al.13 In our study 66% isolation of A. baumannii was from lower respiratory tract samples, which was in
accordance with jaggi et al5, Saleem et al12, Liling et al13 who recovered 56.9%, 45.1%, 78.6% isolates respectively from
LRT samples. Liling et al13 reported much higher (78.6%) isolation of A. baumannii from respiratory samples, which
could be explained by the fact their study included the hospitalized patient only. In contrast to our study Lahiri et al105 and
Mindolli et al14 reported 7.8% and 28.5% isolates of A. baumannii from LRT samples, Which was lower than in the
present study. This could be explained by the fact that the majority of LRT samples in our study were from ICUs, where
Acinetobacter spp. can cause higher cross contamination by virtue of its presence in ICU environments. The isolation rate
of A. baumannii in the present study, from pus and urine samples was 10% and 4% respectively which was similar to
other studies Viller et al15, Lahiri et al10, 17.1 % and 31.0 % and 11.1% and 51.3% respectively.
In our study 76% Acinetobacter isolates were recovered from ICU patients and only 24% isolates were from various
wards. Our study is in accordance with the study done by Hakima K et al16 who reported 76% Acinetobacter isolates from
ICU patients in 2005 and 82% in 2010. In contrast to our study Jaggi et al5 and Sinha et al reported the 22.6% and 22.4%
Acinetobacter baumannii from the ICU patients. The high rate of isolation in our ICU corroborates the fact that a lot of
risk factors associated with Acinetobacter infection exist in the ICU like potential environmental reservoirs, opportunities
for cross transmission, sick, immune compromised patients who are colonized, patients having multiple wounds and
indwelling devices, heavy use of broad spectrum antibiotics and frequent contamination of the hands of health care
workers while patient care.

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 410
Research Publish Journals
The male to female ratio among patients with Acinetobacter infections in the present study was 1.7:1, which was in
accordance with the study done by various authors in India who reported male to female ratio ranging from 1.6:1-1.7:114,17
In the present study, maximum number of A. baumannii were isolated from patients belonging to the age group 21-30
years (29%), followed by >50 years (29%), 11-20 years (12%) and 31-40 years (12%) respectively. The present study
was similar to the study conducted by Mindolli et al14 and Rubina el al17 who also reported maximum number of
Acinetobacter isolates from the patients of >50-60 years of age. P-value was statistically significant in age group 21-30
years. In the present study, the significant risk factor for Acinetobacter baumannii infection were age group >55 years, in
old age patients immune system was weak. Various studies were reported that old age also acts as predisposing factors for
Acinetobacter baumannii infections.15
We studied antimicrobial resistance pattern of clinical isolates of A. baumannii against 03 drugs belonging to Carbapenem
group. In our study all isolates of A. baumannii were 60-61% of the isolates were resistant to doripenem and meropenem
whereas, 19% isolates were resistant to imipenem. The studies by various authors viz, Jaggi et al4 and Tripathi et al18
reported 89.6% and 43% resistance to imipenem which was higher than the present study whereas, studies done by
Rubina et al17, Aktas et al19, Oberoi et a20 Sinha et al21 reported lower resistance to carbapenems in comparison to the
present studies. A surveillance study from MYSTIC (meropenem yearly Susceptibility test information collection)
programme 2006 reported resistance rate of 43.4% and 42.5% for meropenem and imipenem respectively. In another
large surveillance study, susceptibility of A. baumannii to imipenem was lower for isolates in Latin America and in Asia–
Pacific region (60.6%, 69.2% respectively) than in those from Europe and North America (85.9% and 88.6%
respectively).22 A recent surveillance study conducted in United States reported only 60.2% susceptibility to imipenem.23
It was observed that the infections caused by A. baumannii were commonest in the ICU patients (76%), followed by the
patients admitted in wards (24%), the maximum no of A. baumannii were isolated from endo-tracheal aspirate (66%), pus
(10%), blood (9%) and Et tip (7%) and the carbapenems group drugs was most effective drug 81% (imipenem) and
sensitive drugs were doripenem 40% and meropenem 39%. P-value was significant in carbapenems.
5. CONCLUSION
This study concludes that the treatment of Acinetobacter infection should be prescribed on the basis of antimicrobial
sensitivity reports and in judicious way to decrease the emergence of drug resistant isolate. Sharing of expertise,
cooperation and collaboration between the clinicians using antibiotic therapy and clinical microbiologist at the regional
level may be the simplest and most useful public health measure to optimise the use of antibiotics and manage infectious
disease. As efflux mechanism is getting widespread in hospitalized patients, especially in ICU patients, efforts should be
aimed at detecting such resistant bacteria for controlling infections caused by them, and finally, providing better
alternative therapies against these notorious organisms.
REFERENCES
[1] Jones ME, Draghi DC, Thornsberry C, Karlowsky JA, Sahm DF Wenzel RP. Emerging resistance among bacterial
pathogens in the intensive care unit—A European and North American Surveillance study (2000–2002). Ann Clin
Microbiol Antimicrob 2004;3(14):1-11.
[2] Horan TC, White JW, Jarvis WR, Emori G, Culver DH, Munn VP et al. Hospital Infections Program Center for
Infectious Diseases. Centers for disease control. Nosocomial infection surveillance 1984. CDC summ 1986;35:17-
29.
[3] Turner PJ. Meropenem activity against European isolates: report on the MYSTIC (Meropenem Yearly Susceptibility
Test Information Collection) 2006 results. Diagn Microbiol Infect Dis 2008;60:185-92.
[4] Ng PC, Herrington RA, Beane CA, Ghoneim ATM Dear PRF. An outbreak of Acinetobacter septicaemia in a
neonatal intensive care unit. J hospital infect 1989;14:363-8.
[5] Jaggi N, Sissodia P, Sharma L. Acinetobacter baumannii isolates in a tertiary care hospital: Antimicrobial resistance
and clinical significance. J Microbiol and Infect Dis 2012;2(2):57-63.
[6] Carr EL, Kampfer P, Patel BK, Gurtler V, Seviour RJ. Seven novel species of Acinetobacter isolated from activated
sludge. Int J Sys Evol Microbiol 2003;53:953-63.

International Journal of Healthcare Sciences ISSN 2348-5728 (Online)
Vol. 4, Issue 1, pp: (406-411), Month: April 2016 - September 2016, Available at: www.researchpublish.com
Page | 411
Research Publish Journals
[7] Poirell L, Nordman P. Carbapenem resistance in Acinetobacter baumanni- mechanism and epidemiology. Clin
Microb Infec 2006;12:826-36.
[8] Tripodi MF, Durante E, Fortunato R. Comparative activities of colistin, rifampicin, imipenem against epidemic
multidrug resistant Acinetobacter baumannii. Int J Antimicro Agents 30:537-40.
[9] Siau H, Yuen KY, Ho PL, Wong SSY Woo PCY. Acinetobacter Bactermia in Hong Kong: Prospective Study and
Review. Clin Infect Dis 1999;28:26-30.
[10] Lahiri KK, Mani NS, Purai SS. Acinetobacter spp as Nosocomial pathogen: clinical significance and antimicrobial
sensitivity. Med J Armed Forces India 2004;60:7-10
[11] Prashanth K, Badrinath S. Simplified phenotypic test for identification of Acinetobacter spp. and their antimicrobial
susceptibility status. J Med Microbio 2000;49:773-8.
[12] Saleem AF, Ahmed I, Mir F, Ali SR, Zaidi AKM. Pan resistant Acinetobacter infection in neonates in Karachi ,
Pakistan J Infect Dev C tries 2010;4:30-7.
[13] Liling L, CaoY, Xin QD, Dong BZ, Zhang BX. 112 clinical isolates of Acinetobacter distribution and drug
resistance analysis. Available at: http://eng.hi138.com Accessed Nov 11, 2010.
[14] Mindolli PB , Salmani MP, Vishwanth G, Manumanthappa AR. Identification and speciation of Acinetobacter and
their antimicrobial susceptibility testing. Al Ameen J Med Sci 2010 2010;3:345-9.
[15] Villers D , Espaze E, Burel MC, Giauffret F, Ninin E et al . Nosocomial Acinetobacterbaumannii infection:
microbiological and clinical epidemiology Annal Int Med 1998;129:82-9.
[16] Kabbaj H, Seffar M, Belefquih B, prevalence of MBL producing A. baumannii in a Moroccon hospital ISRN review
2013;7:3.
[17] Lone R, ShahA, KadraSM, Lone S. Acinetobacter –an emerging nosocomial pathogen . Middle East J Fam
2009;7:13-6.
[18] Tripathi P, Gajbhiye S. Prevalence of Multidrug Resistance, ESBL andMBL production in Acinetobacter spp.
IJRTS 2013;6:139-43.
[19] Aktas O, Ozbek A. Prevalence and in vitro antimicrobial susceptibility patterns of Acinetobacter strains isolated
from patients in ICU . J Int Med Res 2003;31:272-80.
[20] Oberoi A, Aggarwal A, Lal M. A decade of an underestimated nosocomial pathogen Acinetobacter in a tertiary care
hospital in Punjab .J K sci 2009;11:24-6.
[21] Sinha N, Agarwal J, Singh M, Analysis of carbapenem-resistant Acinetobacter from a tertiary care setting in North
India IJMM2013;31(1): 60-63.
[22] Gales AC, Jones RN, Sader HS. Global assessment of the antimicrobial activity of polymyxin B against 54731
clinical isolates of Gram-negative bacilli. Clin Microbiol Infect 2006;12:315-21.
[23] Halstead DC, Abid J, Dowzicky MJ. Antimicrobial susceptibility among Acinetobactercalcoaceticus-baumannii
complex and Enterobacteriaceae collected as part of the tigecycline evaluation and surveillance trial. J Infect Dis
2007;55:49-57.