Antibiotic susceptibility profiles of non-fermenting gram-negative Bacilli at a Tertiary Care Hospital in Patiala, India

Background: Non-fermenting Gram-negative bacilli (NFGNB) have emerged as a major cause of healthcare-associated infections and are innately resistant to many antibiotics. Aim: The aim of this study was to determine the prevalence of NFGNB isolated from various clinical specimens and evaluate their antimicrobial susceptibility profiles. Materials and Methods: This retrospective study was done at our Department of Microbiology from December 2015 to December 2016. NFGNB were isolated from a variety of clinical specimens, plated on blood agar and MacConkey agar and incubated at 37°C for 18–24 h under aerobic conditions. Appropriate biochemical tests were done to identify the organisms isolated. Antibiotic susceptibility test was performed using the modified Kirby–Bauer disc diffusion method using commercially available discs on Mueller–Hinton agar. Data was analyzed using SPSS IBM version 20 . Results: Out of 19065 clinical samples, cultures were positive in 1854 samples. Out of 1854 culture-positive samples, 216 (11.6%) yielded NFGNB. Pseudomonas aeruginosa was the most common NFGNB, isolated in 190/216 (87.96%) samples, followed by Acinetobacter baumannii (17/216, 7.87%). Overall, most of the NFGNB isolates were susceptible to polymyxin B (88.4%), imipenem (82.9%) and cefoperazone + sulbactam (50.9%), and a total of 11 (64.71%) multidrug-resistant A. baumannii (MDRAB) strains were isolated in the study. Conclusion: Our study showed a significantly high prevalence of NFGNB. Isolation of multidrug-resistant P. aeruginosa and MDRAB in the present study raises the concern of rapidly emerging antibiotic resistance in this group of bacteria in our region.