A Molecular Investigation for Staphylococcus aureus in Diabetic Foot Ulcers

Abstract

In Iraq, the high incidence and recurrence rates of diabetic foot ulcers (DFUs) underscore the need for a multifaceted approach to prevention and management. The study aims to direct molecularly detection of the prevalence of S. aureus among DFUs patients using molecular assay and then nucleotide sequencing of some local S. aureus isolates to be documented in the NCBI and identify its association with the GenBank-BLAST S. aureus isolates. Distribution of infection among the age and sex of the study population in addition to the type of medication(s) was also aimed. After disinfecting the skin surrounding the ulcer, pus samples were collected from 73 DFU patients using sterile swabs that were examined molecularly by the PCR assay. DNAs of some positive samples were sequenced and analysed phylogenetically. Targeting the 16S rRNA gene, 20.55% of DFU swabs had positive reactivity to S. aureus. Concerning age, significantly higher prevalence and risk of S. aureus were shown in patients aged ≥61 years old and to a lesser extent among 51- 60 years old when compared to other age groups: 41-50 and ≤40 years old. For sex, although no significant variation was seen among females and males, risk values revealed that males were at higher risk of S. aureus infection than females. Regarding the type of medication, DFU patients who received injectable medication have significantly higher values of prevalence rate and risks than those of oral and mixed medications. In relation to phylogeny, the sequenced data of six local S. aureus strains were submitted in the NCBI database under specified names (DFU1-DFU6) and GenBank IDs (PQ318365.1- PQ318370.1). The findings of phylogenetic tree analysis, homology sequence identity, and NCBI MSA viewer demonstrated that the local S. aureus strains were related to the NCBI-BLAST Iraqi isolate (LC576397.1) at an identity rate ranged from 98.65% to 99.79% and mutation/change at 0.02%. This study confirms, for the first time in Iraq, the phylogenetic linkage of S. aureus isolated from DFU patients to the NCBI-GenBank S. aureus isolates. This study also shows significant differences in prevalence rates and risks of S. aureus among various age and sex groups as well as among DFU patients who received different medications. Therefore, establishing the underlying causes of diabetes and developing effective interventions to prevent and manage its associated complications are crucial steps toward reducing the burden of this widespread disease. Additionally, the high incidence and recurrence rates of DFU underscore the need for a multifaceted approach to prevention and management.