Antibiotic Susceptibility Profile of Gram Negative Bacteria Isolated from Clinical Samples in a Tertiary Care Hospital

The increasing occurrence of antimicrobial resistance in Gram-negative bacteria poses a significant challenge to healthcare systems worldwide. This study aimed to assess the antimicrobial susceptibility patterns of Gram-negative bacteria isolated from diverse clinical samples at Sukraraj Tropical and Infectious Disease Hospital in Teku, Kathmandu. A total of 737 clinical samples (blood, sputum, and urine) were collected over two months, April 2023 to June 2023 and processed for bacterial culture and identification. The Gram-negative bacteria were identified following conventional methods including Gram staining and various biochemical tests. An antibiotic susceptibility test was performed using the modified Kirby-Bauer disc diffusion method on Mueller Hinton agar (MHA) media. The isolates were tested for multi-drug resistance as well as Extended-spectrum beta-lactamase (ESBL). Of the 74 bacterial isolates, 62 (83.8%) were Gram-negative. The most prevalent bacteria were found to be E. coli (26, 41.9%) followed by S. Typhi (12, 19.4%), Pseudomonas spp. (9, 14.5%) and Klebsiella spp. (8, 12.9%). Considering the frequency of antibiotics used, isolates showed the highest sensitivity to gentamicin (54, 87.1%). In contrast, the highest resistance was observed against cefixime (24, 38.7%). Among the 26 E. coli isolates, 13 (50%) were detected as multidrug-resistant (MDR). Among the 30 urinary isolates examined, 12 (40%) tested ESBL positive during preliminary screening. Of these 12 preliminary positives, only one isolate was confirmed to produce ESBL. The findings emphasize the necessity of ongoing monitoring of antibiotic resistance patterns and the crucial role of antibiotic stewardship in controlling the spread of resistant Gram-negative bacteria in clinical environments.