Isolation and study of Antimicrobial susceptibility and resistance patterns of Acinetobacter spp. from Intensive Care Units of a tertiary care hospital in Bengaluru

BACKGROUND: Acinetobacter spp. is a ubiquitous gram-negative non-motile, encapsulated, and non-fermentative coccobacillus that has emerged as an important nosocomial pathogen. The incidence of Acinetobacter pneumonia (especially LRTIs) in the Intensive care Units (ICU) has increased significantly, accounting for 6-30% of all ICU infections. Emerging infections due to multi drug resistant (MDR) strains of Acinetobacter sp. in the ICU is a therapeutic concern for clinicians worldwide. Materials and Methods: A retrospective study was undertaken in the Department of Microbiology, VIMS & RC, Bengaluru, to isolate Acinetobacter spp and study antibiotic resistance patterns from various clinical samples in ICUs, including pus, sputum, tracheal aspirates, catheter tips from June 2013 to May 2014. Samples were processed and identified by standard protocol. Acinetobacter isolates were tested for antibiotic resistance by as per CLSI guidelines. Results: A total of 62(12.6%) cases of Acinetobacter spp were isolated from 491 samples. Most of the Acinetobacter spp. were highly resistant to Ampicillin (83.9%), Amikacin (77.4%), Gentamicin (77.4%), Ceftazidime (85.5%), Ceftriaxone (62.9%), Cefotaxime (77.4%), Imipenem (40.3%), Meropenem (50.0%), Cotrimoxazole (83.9%), Piperacillin-Tazobactam (46.8%). Out of the 62 isolates, 56 (90.3%) were MDR. Carbepenems were seen to be relatively still effective on the Acinetobacter isolates. Conclusion: This study showed that Acinetobacter spp. isolated showed multi drug resistance to antibiotics particularly to the Penicillins, the third generation Cephalosporins, Aminoglycosides and the Carbapenems. To avoid resistance, antibiotics should be used judiciously and urgent steps should be taken to identify and prevent spread of such resistant strains of Acinetobacter spp in ICUs.