Frequency of Micro-Organisms and Antimicrobial Sensitivity Pattern in Diabetic Foot Infection at Tertiary Care Hospital in Quetta

Abstract

Background: Diabetic foot infection (DFI) is a frequent and severe complication of diabetes mellitus, associated with prolonged hospitalization, amputation, and increased mortality. The microbiological spectrum and resistance profiles of DFI vary across regions, necessitating local data to inform empirical treatment. Pakistan faces a rising burden of diabetes, yet data from Quetta, the capital of Balochistan province, remain scarce. Objective: To determine the frequency of microorganisms causing DFI and their antimicrobial susceptibility patterns in patients admitted to a tertiary care hospital in Quetta, Pakistan. Methods: A cross-sectional study was conducted from December 2024 to May 2025 at Bolan Medical Complex Hospital, Quetta. One hundred adult patients with clinically confirmed DFI were consecutively enrolled. Deep tissue specimens were collected post-debridement for culture and susceptibility testing using CLSI guidelines. Demographic and clinical variables were recorded, and associations with multidrug resistance (MDR) were analyzed using chi-square tests. Statistical analysis was performed with SPSS version 24.0. Results: The mean age of patients was 58.6 ± 9.8 years, with 63% male and 54% having diabetes duration >10 years. Gram-negative organisms predominated (62%), followed by Gram-positive organisms (34%) and mixed isolates (4%). Pseudomonas aeruginosa (21%) and Escherichia coli (18%) were the most common Gram-negative isolates, while Staphylococcus aureus was the leading Gram-positive (17%), with 42% MRSA. Gram-negative isolates showed highest susceptibility to amikacin (81%), meropenem (77%), and piperacillin–tazobactam (71%), whereas Gram-positive isolates were most sensitive to vancomycin (95%) and linezolid (92%). Prior antibiotic exposure was significantly associated with MDR (OR 2.11, 95% CI: 1.05–4.56, p=0.03).

Conclusion: Gram-negative bacilli are the predominant cause of DFIs in Quetta, exhibiting extensive resistance to cephalosporins and fluoroquinolones. Amikacin, carbapenems, and piperacillin–tazobactam remain reliable for Gram-negative infections, while vancomycin and linezolid are effective against MRSA. Local antibiograms should guide empiric therapy, and stewardship programs are essential to mitigate further resistance.