Characterization and Antimicrobial Susceptibility Patterns of Clinically Significant Non-fermenting Gram-Negative...

Background Non-fermenting Gram-negative bacilli (NFGNB) have emerged as significant opportunistic pathogens associated with infections in healthcare settings and multidrug resistance. Their ability to persist in hospital settings and develop resistance to multiple antimicrobial agents poses a serious challenge to patient management. The current study aimed to determine the distribution of NFGNB isolates across different clinical samples and to evaluate their antimicrobial susceptibility and multidrug resistance patterns. Materials and methods A cross-sectional investigation was carried out on 127 NFGNB that were isolated from clinical samples received in the Department of Microbiology Laboratory of a tertiary care hospital. Antimicrobial susceptibility testing was performed in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines, and the isolates were identified using conventional microbiological techniques. Demographic characteristics, specimen distribution, bacterial profile and multidrug resistance patterns were studied. Results A total of 127 NFGNB isolates were recovered, of which 86 (67.72%) were from male patients and 41 (32.28%) were from female patients. The highest prevalence of NFGNB was observed in the 61-70-year age group, with 26 (20.47%) isolates, followed by the 51-60-year age group, with 23 (18.11%) isolates. Endotracheal (ET) aspirates were the most common specimen source, accounting for 34 (26.77%) isolates, followed by pus/discharge/wound swabs with 27 (21.26%) and urine with 26 (20.47%) isolates. 88 (69.29%) of the NFGNB isolates were obtained from patients admitted to the intensive care unit, whereas 39 (30.71%) were isolated from patients admitted to the wards. Pseudomonas aeruginosa was the most common isolate, accounting for 61 (48.03%) isolates, followed by Acinetobacter baumannii with 53 (41.73%) and Stenotrophomonas maltophilia with 13 (10.24%) isolates. A. baumannii and P. aeruginosa were highly carbapenem-resistant and fluoroquinolones and β-lactam antibiotics. Conclusion A. baumannii and P. aeruginosa were the predominant NFGNB isolates and exhibited a high rate of multidrug resistance, whereas Stenotrophomonas maltophilia remained susceptible to the antibiotics tested. Continuous surveillance of antibiotic resistance patterns, implementation of prevention and management of infections, and policies for antimicrobial stewardship are crucial to curb the dissemination of multidrug-resistant NFGNB and optimize patient outcomes.