Antibiotic Sensitivity and ESBL Prevalence among Gram-Negative Bacteria in a Tertiary Care Hospital

Abstract

The steady upsurge in the prevalence of ESBL-producing Gram negative bacteria has become a significant menace to the
healthcare systems across the globe, including Pakistan. This study was carried out from November 2023 to May 2024 to determine the prevalence and antibiotic susceptibility of Gram negative bacteria in clinical samples belonging to the local population of South Punjab, Pakistan as well as to explicate the prevalence of ESBL-producers among the isolates. Various clinical samples were considered including blood cultures, urine, wound swabs, pus, and tracheal secretion. The isolation was followed by Gram staining and biochemical characterization, after which antibiotic susceptibility testing was conducted in accordance with the CLSI guidelines, and ESBLs were detected phenotypically by a double disk synergy test. A total of 111 Gram-negative bacterial isolates were obtained from 238 clinical specimens. These included Escherichia coli, Klebsiella spp., Acinetobacter spp., Pseudomonas aeruginosa, Citrobacter spp., and Proteus mirabilis, in the decreasing order of prevalence. The antibiotic susceptibility profile showed that 76.70% of the isolates were resistant to at least one of the eight selected antibiotics. Amikacin was the most effective antibiotic against most isolates while Colistin was the least effective drug. Overall, 35% of the isolates were positive for the ESBL detection test while 65% were negative. Escherichia coli showed the highest prevalence rate for ESBL followed by Proteus mirabilis, Klebsiella spp., Citrobacter spp., Pseudomonas aeruginosa, and Acinetobacter spp., respectively. The results emphasized a high prevalence of antibiotic resistance among Gram-negative isolates and a rising ESBL detection rate among the pathogens in clinical settings.