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Year : 2012  |  Volume : 53  |  Issue : 3  |  Page : 126-128  

Multidrug-resistant acinetobacter infection and their susceptibility patterns in a tertiary care hospital

Department of Microbiology, Institute of Post-Graduate Medical Education and Research, Malda Medical College and Hospital, Kolkata, West Bengal, India

Date of Web Publication6-Dec-2012

Correspondence Address:
Rajdeep Saha
497/1, Swami Vivekananda Road, 2nd Lane, Birati, Kolkata- 700 051, West Bengal
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0300-1652.104379

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Background: Antibiotic-resistant Acinetobacter nosocomial infection is a leading problem. It acts as an opportunistic pathogen to cause a wide spectrum of infection including nosocomial pneumonia, meningitis, endocarditis, skin and soft tissue infections, urinary tract infection, conjunctivitis, burn wound infection and bacteremia. Multidrug-resistant Acinetobacter infection creates a great problem in hospital setting. Materials and Methods: The clinical specimens obtained from ICU and different surgical and medical wards were investigated using standard microbiological techniques to know the distribution of and their resistant profile. Antimicrobial resistance was studied using the modified Kirby Bauer disk diffusion technique following the CLSI protocol. Results: Major infections found in different medical wards, surgical wards and ICU were due to Acinetobacter baumannii (74.02%), A. lowfii (14.2%), A. haemolyticus (7.79%), A. junii (3.8%) among Acinetobacter spices. Acinetobacter showed increased resistant against majority of commercially available drugs imipenem (5.2%), meropenem (9.75%), piperacillin-tazobactum (18.2%), netilmicin (16.24%), amikacin (14.29%), ceftazidime (74.1%), gentamicin (70.13%), ofloxacin (42.21%). Conclusion : A. baumannii was found to be associated with UTI, RTI, septicemia, bacteremia, and meningitis and wound infection. A. baumannii displayed higher resistance to more number of antibiotics than other nosocomial pathogens from ICU.

Keywords: Acinetobacter , antibiotic resistance, nosocomial infection

How to cite this article:
Rit K, Saha R. Multidrug-resistant acinetobacter infection and their susceptibility patterns in a tertiary care hospital. Niger Med J 2012;53:126-8

How to cite this URL:
Rit K, Saha R. Multidrug-resistant acinetobacter infection and their susceptibility patterns in a tertiary care hospital. Niger Med J [serial online] 2012 [cited 2021 May 11];53:126-8. Available from: https://www.nigeriamedj.com/text.asp?2012/53/3/126/104379

   Introduction Top

Acinetobacter baumannii is an opportunistic pathogen that is frequently involved in outbreaks of infection occurring mostly in intensive care units. [1] Members of genus Acinetobacter is gram negative, nonmotile nonspore forming encapsulated coccobacilli belonging to family  Neisseria More Detailsceae. [2] It is an opportunistic pathogen found to be associated with wide spectrum of infection including nosocomial pneumonia, meningitis, endocarditis, skin and soft tissue infections, urinary tract infection, conjunctivitis, burn wound infection and bacteremia posing risk for high mortality. [3],[4] Acinetobacter pneumonia generally occurs in patients with diminished host defenses (e.g. alcoholism, tobacco use, diabetes mellitus, and renal failure, underlying pulmonary disease). [5],[6],[7] Outbreak of Acinetobacter infections is linked to contaminated respiratory equipments, intravascular access devices, bedding materials and transmission via hands of hospital personal. [8] It typically colonizes skin and indwelling plastic devices of the hospitalized patients. [9] MDR strains of Acinetobacter isolates are a growing problem and have been widely reported. [10] Most A. baumannnii are now resistant to ampicillin, carbenicillin, cefotaxime, and chloramphenicol, with some centers reporting up to 91% of nosocomial Acinetobacter resistant to Resistance to tobramycin and amikacin is increasing. Fluoroquinolones, colistin, imipenem, and meropenem may retain activity against nosocomial Acinetobacter. [11] Ertapenem, the newest of the carbapenems, has little intrinsic activity against Acinetobacter and should not be used. [12] However, the rapid development of significant quinolone resistance in France, aminoglycoside resistance in Germany, and carbapenem resistance in selected regions worldwide raises an important therapeutic problem. [13],[14]

   Materials and Methods Top

The study was conducted for a period of 2 years. A total 4180 specimens like blood sample, pus, CSF, and other body fluids were subjected to simplified phenotypic identification scheme [Table 1]. Antimicrobial susceptibility testing was done. Presumptive identification of Acinetobacter was made by inoculation on MacConkey agar medium incubated at 37°C. Urine samples were inoculated on CLED also. All nonlactose fermenting members subjected to gram staining, oxidase, catalase, and hanging drop preparation. Acinetobactor are gram-negative bacilli or coccobacilli, oxidase negative, nonmotile, catalase positive. Speciation was done on the basis of glucose oxidation, gelatine liquefaction, haemolysis, growth at 35° and 42°C. Antimicrobial susceptibility testing was done by modified Kirby-Bauer disk diffusion method with imipenem, meropenem, piperacillin-tazobactum, netilmicin, amikacin, ceftazidime, gentamicin, ofloxacin, chloramphenicol disks. The screening test for detection of inducible beta lactamases (IBL), extended spectrum beta lactamases (ESBL), and MBL was done by the disk approximation method and double disk synergy respectively.
Table 1: Identification scheme of Acinetobacter species

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   Results Top

During the period of study from January 2010 to December 2011 a total of 4180 samples were examined from of different age group admitted in various medical wards, surgical wards and ICU. Nonfermenter isolates account for 12% and Acinetobacter isolates account for 4.5% of total organism isolated during the study period. Pseudomonas was the most common nonfermenter (69.44% of total non fermenter isolated).

The male: female ratio was 1.5:1. Acinetobacter infection was more common in patients of aged over 40 yrs. Most of these patients had respiratory problems like COPD, bronchial asthma, respiratory failure. Infection in neonates was common in preterm babies. In 87.5% sample growth was monomicrobial. In 12.5% sample growth was polymicrobial.  Escherichia More Details coli was the most common associated organism with Acinetobacter in the case of UTI. Staphylococcus aureus was the associated organism in the case of wound infection, cellulitis, and abcess. Acinetobacter was isolated most commonly from surgical ward, medical ward, burn unit, and two isolates were isolated from humidifier ventilator and two isolates from the OT table.

The present study shows more strains belonging to Acinetobacter baumanii complex 114 (74.02%) of total Acinetobacter isolates [Table 2]. Other species includes A.lowfii 22 isolates (14.2%), A. haemolyticus 12 (7.79%) isolates, A junni 06 (3.8%) isolates.
Table 2: Different spices of Acinetobacter isolated from clinical samples

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One of the striking features of genus Acinetobacter is the ability to develop antibiotic resistant extremely rapid in response to challenge with new antibiotics. In the present study, strains were resistant to imipenem (5.2%), meropenem (9.75%), piperacilin-tazobactum (18.2%), netilmicin (16.24%), amikacin (14.29%), ceftazidime (74.1%), gentamicin (70.13%), ofloxacin ((42.21%), chloramphenicol (92.20%) [Table 3]. IBL and ESBL were detected 10% and 8% isolates of Acinetobacter respectively. The difference in susceptibility pattern was due to environmental factors and different pattern of antimicrobial usage.
Table 3: Sensitivity pattern of Acinetobacter isolate to different antibiotic

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   Discussion Top

Acinetobacter species has emerged as an important pathogen causing life-threatening infections both in community and hospital. Rapid emergence of multidrug-resistant Acinetobacter has further made the situation critical. [15] Acinetobacter is found ubiquitously in nature, soil and also in skin as commensal. Infection is commonly transmitted through aerosol. Prior use of broad spectrum antibiotics, cross infection by hand of hospital staff, ventilator machine are all potential risk factors for development of multidrug-resistant Acinetobacter infection in hospital. [16] In one study at JIPMER hospital respiratory infections due to Acinetobacter in mechanically ventilated patients in ICU were 44.7%. One recent study revealed that Acinetobacter spp. was responsible for 35% of ventilator associated pneumonia (VAP), making it the most conspicuous and dominant pathogen among all other bacteria encountered in that study. [17]

In our study, a total of 4180 samples were studied, out of which 504 (12.05%, n=4180) nonfermenters were isolated [Table 4]. Pseudomonas was the most common isolated nonfermenter (69.44%, n=504). Acinetobacter species accounted for (30.55%, n=504) of total nonfermenter and 4.5% of total positive culture. Most of the isolated Acinetobacter species were sensitive to imipenem, meropenem. However, 10% of them were IBL producers and 8% were ESBL producers.
Table 4: Number of other nonfermenter and Acinetobacter isolated from various samples

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   Conclusion Top

In conclusion, multidrug-resistant A. baumannii was responsible for majority of the Acinetobacter infections at our hospital. Injudicious use of antibiotics, mechanical ventilation, cross infection was found to be potential risk factors for development of Acinetobacter infection.

During routine microbiological work nonfermenter GNB other than Pseudomonas aeruginosa are not taken seriously and are dismissed as contaminants. But the rate of isolation of Acinetobacter in various studies indicates its role as nosocomial pathogen and also as an agent of community acquired infection. Traditional typing methods like phenotyping and antibiogram typing have advantage over genotyping as they are readily available and cost effective.

   References Top

1.Paterson DL. The epidemiological profile of infections with multidrug-resistant pseudomonas aeruginosa and acinetobacter species. Clin Infec Dis 2006;43:S43-8.  Back to cited text no. 1
2.Bergogne-Bérézin E, Towner JK. Acinetobacter spp. as nosocomial pathogens: Microbiological, clinical and epidemiological features. Clin Microbiol Rev 1996;9:148-51.  Back to cited text no. 2
3.Koneman WE, Allen DS, Dowell VR Jr, Sommers MH. The nonfermentative Gram negative bacilli. In: Colour Atlas and Text Book of Diagnostic Microbiology. 2 nd ed. Philadelphia/St. Louis/London: J. B. Lippincott Company; 1983. p. 125-84.  Back to cited text no. 3
4.Anstey NM, Currie BJ, Withnall KM. Community-acquired Acinetobacter pneumonia in the northern territory of Australia. Clin Infect Dis 1992;14:83-91.  Back to cited text no. 4
5.Goodhart GL, Abrutyn E, Watson R, Root RK, Egert J. Community acquired Acinetobacter calcoaceticus var anitratus pneumonia. JAMA 1977;238:1516-8.  Back to cited text no. 5
6.Anstey NM, Currie BJ, Hassell M, Palmer D, Dwyer B, Seifert H. Community-acquired bacteremic Acinetobacter pneumonia in tropical Australia is caused by diverse strains of Acinetobacter baumannii, with carriage in the throat of at-risk groups. J Clin Microbiol 2002;40:685-6.  Back to cited text no. 6
7.Chen MZ, Hsueh PR, Lee LN, Yu CJ, Yang PC, Luh KT. Severe community-acquired pneumonia due to Acinetobacter baumannii. Chest 2001;120:1072-7.  Back to cited text no. 7
8.Neely AN, Maley MP, Warden GD. Computer keyboards as reservoirs for Acinetobacter baumannii in a burn hospital. Clin Infect Dis 1999;29:1358-60.  Back to cited text no. 8
9.Glew RH, Moellering RC Jr, Kunz LJ. Infections with Acinetobacter calcoaceticus (Herellea vaginicola): Clinical and laboratory studies. Medicine (Baltimore) 1977;56:79-97.  Back to cited text no. 9
10.Paramasivan CN, Rao RS, Sivadasan K, Anupurba S, Kanungo R, Prabhekar R. Non-fermenting Gram negative bacteria in human infections. Indian J Med Microbiol 1988;6:73-9.  Back to cited text no. 10
11.Seifert H, Baginski R, Schulze A, Pulverer G. Antimicrobial susceptibility of Acinetobacter species. Antimicrob Agents Chemother 1993;37:750-3.  Back to cited text no. 11
12.Fuchs PC, Barry AL, Brown SD. In vitro activities of ertapenem (MK-0826) against clinical isolates from eleven North American medical centers. Antimicrob Agents Chemother 2001;45:1915-8.  Back to cited text no. 12
13.Manikal VM, Landman D, Saurina G, Oydna E, Lal H, Quale J. Endemic carbapenem-resistant Acinetobacter species in Brooklyn, New York: Citywide prevalence, interinstitutional spread, and relation to antibiotic use. Clin Infect Dis 2000;31:101-6.  Back to cited text no. 13
14.Corbella X, Montero A, Pujol M, Domínguez MA, Ayats J, Argerich MJ. Emergence and rapid spread of carbapenem resistance during a large and sustained hospital outbreak of multiresistant Acinetobacter baumannii. J Clin Microbiol 2000;38:4086-95.  Back to cited text no. 14
15.Bergogue-Berezin E, Towner KJ. Acinetobacter species as nosocomial pathogen: Microbiological, clinical and epidemiological features. Clin Microbiol Rev 1996;9:148-65.  Back to cited text no. 15
16.Gómez J, Simmarro E, Banos V, Requena L, Ruiz J, Gracia F, et al. Six-year prospective study of risk and prognostic factors in patients with nosocomial sepsis caused by Acinetobacter baumannii. Eur J Clin Microbiol Infect Dis 1999;18:358-61.  Back to cited text no. 16
17.Sofianou DC, Constandinidis TC, Yannacou M, Anastasiou H, Sofianos E. Analysis of risk factors for ventilator-associated pneumonia in a multidisciplinary Intensive care unit. Eur J Clin Microbiol Infect Dis 2000;19:460-3.  Back to cited text no. 17


  [Table 1], [Table 2], [Table 3], [Table 4]

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