Molecular characterization and antibiotic susceptibility pattern of bacterial strains isolated from diabetic foot ulcers

Abstract

Introduction: Diabetic wounds are highly susceptible to a range of pathogens, particularly bacteria, due to the immunocompromised state of diabetic patients. Although diabetic wound isolates are typically polymicrobial, S. aureus is the most common bacteria found in such isolates. Objective: The objectives of this study were to identify the different bacterial isolates present in each sample of diabetic foot ulcers, determine the minimum inhibitory concentration of the identified bacterial strains to various antibiotics, and identify the genes responsible for drug resistance in multidrug-resistant bacterial strains. Materials and methods: A cross-sectional prospective study was conducted at the Endocrinology Unit, Hayatabad Medical Complex, Peshawar, Pakistan, from November 2019 to March 2020. A total of n = 140 samples from diabetic foot ulcers were aseptically collected and evaluated for their sensitivity to antibacterial drugs commonly used in the study area. The samples were inoculated into various media and cultured, and biochemical and molecular analyses were conducted according to the Clinical Laboratory Institute Guidelines. Results: A total of 122 bacterial isolates were obtained out of a total of 144. The results of antibiotics susceptibility testing showed that gram-positive isolates were more resistant to penicillin G (93.18 %), but exhibited sensitivity to vancomycin (100 %) and linezolid (LZD) (95 %). Gram-negative isolates were found to be 100 % resistant to penicillin, such as amoxicillin (AMC), and sulphonamides, such as sulphamethoxazole/trimethoprim (SXT) groups of antibiotics. A total of 36 (29.50 %) multidrug-resistant (MDR) isolates were identified. MDR isolates exhibited good sensitivity to meronem (MEM), i.e. 97 %, and were highly resistant to sulphamethoxazole/trimethoprim and clindamycin, i.e. 100 %. Conclusion: Gram-positive isolates were resistant to penicillin G (93.18 %) but sensitive to vancomycin (100 %) and linezolid (95 %). Gram-negative isolates were resistant to penicillin and sulphonamides. Among the isolates, 29.50 % were multidrug-resistant (MDR), with high resistance to sulphamethoxazole/trimethoprim and clindamycin but good sensitivity to meronem (97 %). Two sentence summary: This study highlights the emerging problem that world is facing right now in the form of antimicrobial resistance. Our study showed increased antimicrobial resistance in wounds of diabetic foot ulcers.