Bacterial spectrum from diabetic foot Ulcers: A study of antibiotic resistance patterns and phylogenetic diversity

Diabetic foot ulcer (DFU) is one of the most detrimental impacts of diabetes mellitus associated with osteomyelitis and gangrene, accounting for at least two-thirds of non-traumatic amputations with a 5-year survival rate. In this perspective, antimicrobial resistance has been a cause for grave concern for the last 50 years and is among the World Health Organization most pressing "calls to action" for the 21st century. The current study aimed to identify bacterial pathogens present in DFU, their antibiotic resistance profiles, and genetic diversity. A total of 180 samples were collected from DFU patients hospitalized at healthcare institutions in Pakistan. All samples were cultured on three distinct types of media − nutritional agar, McConkey agar, and mannitol salt agar to identify both Gram-negative and Gram-positive bacteria. Biochemical, morphological, and molecular (16 s rRNA) investigations were employed to characterize the bacterial species. Out of the 180 samples collected, Staphylococcus aureus (S. aureus) was isolated from 98 (54 %) samples, Escherichia coli (E. coli) from 75 (41.6 %) samples, S. epidermidis from 20 (11.1 %) samples, and Pseudomonas aeruginosa (P. aeruginosa) from 18 (10 %) samples. Furthermore, PCR amplification confirmed the presence of antibiotic resistance genes in the resistant E. coli and S. aureus isolates. In S. aureus, the most commonly found antibiotic resistance genes were erm(B) and aac(6′) aph (2′) whereas in E. coli the prevalent genes were ampC (tetA) and erm (B). The distributions of many genes associated with drug resistance differed from those documented worldwide. These findings will aid in guiding the empirical use of antibiotics for treating diabetic foot infections, thereby reducing the risk of inappropriate antibiotic use and the development of antibiotic resistance.