A study on non-fermenting Gram-negative bacilli: their isolation and in vitro susceptibility in a tertiary care hospital in Central India

Background: aerobic, non-spore forming Non-Fermenting Gram-Negative Bacilli (NFGNB) are significant nosocomial agents. They can cause infections such as bacteraemia, meningitis, pneumonia, urinary tract infection and osteomyelitis especially in immunocompromised hosts. Identification and monitoring of susceptibility pattern thus become of utmost importance in the management of these Multidrug Resistant (MDR) pathogens. The aim of this study was to determine the isolation rate of NFGNB along with its susceptibility pattern in all the clinical samples. Materials and Methods: the study was conducted in the Microbiology Department of a tertiary care hospital. The NFGNB were identified using a standard protocol that included tests for motility, oxidase production, oxidation-fermentation test, gelatin liquefaction, and utilization of 10% lactose. Antibiotic susceptibility testing was performed with Kirby-Bauer disc diffusion method. Results: from a total of 15847 samples 935 (5.90%) NFGNB were isolated. Acinetobacter spp. (50.37%) and Pseudomonas spp. (47.05%) were the most common NFGNB isolated followed by Burkholderia cepacia complex (2.4%) and Stenotrophomonas maltophilia (0.2%). High resistance was observed for cephalosporins, monobactams and quinolones in Pseudomonas aeruginosa. In Acinetobacter spp. high resistance was observed for cephalosporins, cotrimoxazole and Beta Lactam and Beta Lactamase Inhibitor (BL-BLI) combination and quinolones. Conclusions: NFGNB have emerged as an important nosocomial agent, therefore early detection in routine laboratory, monitoring susceptibility pattern, immediate infection control and antimicrobial stewardship programs should be implemented in order to limit the spread of MDR organisms.