Antibiotic susceptibility profile of acinetobacter isolates from various clinical specimens at a tertiary care hospital in South Karnataka

Introduction: Acinetobacter is one of the most common pathogens causing Hospital acquired infections (HAIs) and has taken more and more imperative place as an opportunistic, difficult-to-treat pathogen. Development of drug resistance among them during recent years has made treatment of these infections difficult. Objective: 1) To estimate the prevalence of Acinetobacter isolates among various clinical samples in the study setting. 2) To determine the antimicrobial susceptibility pattern among isolated Acinetobacter species. Materials and Methods: A descriptive study was conducted over a period of one year from November 2012 to October 2013 in the Department of Microbiology, Mysore Medical College and Research Institute, Mysore among 110 Acinetobacter species isolated from various clinical specimens and antibiotic susceptibility testing was performed using Kirby-Bauer disc diffusion technique. Statistical analysis was done using Microsoft office excel 2010. Results: Majority of the Acinetobacter species were isolated from patients younger than 1 year, male patients especially inpatients and that too among those admitted to Intensive care units (ICU) and majority were from pus samples. Antimicrobial susceptibility testing showed maximum resistance 93 (84.54%) to cephalosporin and maximum sensitivity 101(91.81%) to Colistin. Conclusion: This study highlights the need for the surveillance to detect multidrug resistance Acinetobacter species, judicious use of antibiotics and implementation of appropriate infection control measures to control the spread of these strains in the hospital. © 2019 Published by Innovative Publication. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by/4.0/)


Introduction
Acinetobacter is a complex genus and historically, there has been confusion about the existence of multiple species. 1 Worldwide in the past two or three decades, especially since 2005-2006 members of the genus Acinetobacter have emerged from organisms of questionable pathogenicity to pan resistant nosocomial pathogens. 2 Acinetobacter species are gram negative, strictly aerobic, non-fastidious, nonfermenting encapsulated coccobacilli with more than 30 genomic types. It's most important representative is Acinetobacter baumanni.
intricate pathogens "ESKAPE" (Enterococcus faecium, Acinetobacter species are opportunistic pathogens predominantly found in immunocompromised patients. They are widespread in nature, and regarded as commensal microbes of human skin and respiratory tract, however, they may cause serious infections, such as endocarditis, urinary tract infections, pneumonia, wound infections, meningitis, and septicemia, especially in individuals with impaired host defenses. The increased risk of infection is associated with the severity of patient's illness, length of exposure to invasive devices and procedures, increased risk of patient contact with health care personnel and length of stay in ICU. In addition to infection among hospitalized patients, community acquired Acinetobacter infection is increasingly reported in recent years.
The genus Acinetobacter has taken more and more imperative place as an opportunistic, difficult-to-treat pathogen and is accredited as one of the six The appearance of resistant species is attributed to both inappropriate use of antimicrobials and health care associated transmission of drug-resistant strains among patients and have posed significant challenges for clinicians in their treatment. 4 With this background, the present study was undertaken to study antimicrobial susceptibility pattern among Acinetobacter species in the study setting.

Isolation of acinetobacter species
A total of 2750 culture positive clinical samples such as pus, urine, blood, sputum, CSF, endo tracheal aspirate, sputum and other body fluids were inoculated on 5% sheep blood agar and macconkey agar and incubated overnight aerobically at 37 • C. All isolates obtained were further processed and identified by routine microbiological and biochemical tests. In case of urine samples, the isolates were subjected to biochemical tests only if the colony count was significant (>10 5 CFU/ml). Genus Acinetobacter was identified by characteristic colonies (Non Lactosefermenting, glistening, small mucoid colonies), Gram staining pattern as Gram negative coccobacilli, motility as non-motile, and standard biochemical reactions (catalase, oxidase, oxidation-fermentation test, indole production, citrate utilization, urease activity, reaction in triple sugar iron medium. 5 diameters produced and correlating them with the CLSI (Clinical and Laboratory Standard Institute) standards. 6

Data collection
A pretested and semi structured proforma was used to collect data like name, age, sex, clinical presentation, predisposing factors, history of treatment as well as results of antibiotic susceptibility testing for all Acinetobacter isolates.

Statistical analysis
4. Results

1.
Out of 2750 culture positive samples in the present study, 110 were found to be positive for Acinetobacter species thereby making a prevalence of 4%.
3. Table 2  Acinetobacter species have become resistant to nearly all routinely prescribed antimicrobial agents like aminoglycosides, fluoroquinolones, broad-spectrum βlactams and also against cephalosporins and carbapenems.

Materials and Methods
Statistical analysis was performed using Microsoft Excel 2010.

Percentage (%)
This could be probably due to invasive diagnostic procedures; greater quantity of broad spectrum antimicrobials used and prolonged duration of stay in hospital among inpatients. Majority i.e. 51 (46.36%) of Acinetobacter species were isolated from pus samples, which is in agreement with the results reported previously in other studies. Majority i.e. 29 (26.36%) of isolates were from infants similar to the findings of study done by Madhu Sharma et. al. 24 and contrary to few other studies. 12,13,25 This variation could be due to differences in study settings, study design, method of isolation, sampling technique as well as differences in the profile of patients. However, several other studies have stated higher isolation rates from clinical samples like urine, In the present study, Acinetobacter species were found to be resistant to most commonly used antibiotics. The highest resistance was seen in third generation cephalosporins 93(84.54%) which was similar to the findings of other studies. 3,33 Resistance to Imipenem recorded was 57(51.81%) whereas lower resistance was reported by other studies.
The result of the present

Conflict of interest
None.
The present study shows that the significance of Acinetobacter has increased as a nosocomial pathogen in various wards of the hospital because of high potential of this genus to develop multidrug resistance and highlights the need for its surveillance, judicious use of antibiotics andimplementation of appropriate infection control the spread of these strains in the hospital.
Cite this article: Murugesh K, Naik TB, Ravindranath C. Antibiotic susceptibility profile of acinetobacter isolates from various clinical specimens at a tertiary care hospital in South Karnataka. Indian J Microbiol Res 2019;6(4):280-283.