*Kumuda, A., and Pavani, G.
Department of Microbiology, Apollo Institute of Medical Sciences and Research, Hyderabad, India *Correspondence to: kumudarumugam@gmail.com; +918805647838
Abstract
Background: Non-Fermenting Gram-negative bacilli (NFGNB), including Pseudomonas aeruginosa, Acinetobacter species, and Burkholderia species, are emerging as significant opportunistic pathogens, especially in immunocompromised and hospitalized patients. These organisms pose a major therapeutic challenge due to their multidrug-resistance (MDR) and intrinsic resistance mechanisms. The goal of this study is to determine antibiotic susceptibility pattern of NFGNB isolated from clinical specimens of patients in a tertiary care teaching hospital in Hyderabad, India.
Methodology: A descriptive cross-sectional observational study of patients with clinical infections was conducted between December 2024 and April 2025, to identify NFGNB from their clinical specimens. Different clinical samples (blood, sputum, urine, pus and others) were collected from patients of both sexes and all age groups for bacterial isolation using automated Bact/Alert for blood culture and conventional method for other samples. Identification of NFGNB isolates and antimicrobial susceptibility testing (AST) of the isolates against selected antibiotics were performed using the VITEK 2 Compact system, and AST interpretations were made in line with the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Results: During the study period, clinical samples of 1575 patients were processed, 359 were positive for bacterial isolates on cultures, and 32 NFGNB were identified from clinical samples of 32 patients with clinical infections. Among the 32 isolates, Pseudomonas accounted for 78.0% (n=25) followed by Acinetobacter (13.0%, n=4) and Burkholderia (9.0%, n=3). NFGNB infections were more frequent in males (78.0%) and patients aged 51-75 years. Majority (78.0%) of isolates were from inpatients. Pseudomonas showed high resistance to fluoroquinolones (36.0%) but sensitive to piperacillin/tazobactam (84.0%) and β-lactam combinations (76.0%). Acinetobacter isolates exhibited 75.0% resistance to multiple antibiotics but 50.0% were sensitive to carbapenems and β-lactam/β-lactamase inhibitor combinations. Burkholderia isolates showed complete resistance to cefepime, cotrimoxazole and amikacin, but were 100.0% sensitive to piperacillin/tazobactam.
Conclusion: The study underscores the alarming levels of antimicrobial resistance among NFGNB, particularly in hospitalized and elderly patients. The findings highlight the necessity of continuous antimicrobial resistance surveillance, stringent infection control, and robust antibiotic stewardship to combat the growing threat of multidrug-resistant organisms.
Keywords: Non-Fermenting Gram-negative bacilli, Multi-drug resistance, Clinical specimens
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