Diversidade molecular de fatores de virulência em amostras de Staphylococcus aureus isoladas de lesões de pé diabético

Abstract

Diabetes mellitus is a highly prevalent disease in the current human population, which can lead to complications such as diabetic neuropathy and peripheral vascular disease; both are risk factors for the appearance of diabetic foot lesions, which in turn can be aggravated by polymicrobial infections of which the Staphylococcus aureus species is one of the main and most frequent microorganisms present. The present study aimed to analyze genes of common virulence factors in S. aureus (n = 25), isolated from wounds on the feet of patients with diabetes at Hospital Geral de Palmas, Tocantins. The virulence genes (fnbA, fnbB, clfA, clfB, sasX, hlA, hlB, hlgCB, seA, seB, seD, seI, seH, etA, etB, etD, lukED, LukPV, EDIN, arcA, Agr I, Agr II, Agr III and Agr IV), biofilm (icaA, icaB, icaC and icaD) and capsule (cap5 and cap8) were detected by conventional PCR assays. Assay results indicated the presence of TSST genes in 14 samples (56%); arcA in 10 (40%); clfB and etA in 9 (36%); icaA in 8 (32%); cap5 and LukPV in 6 (24%); icaD in 5 (20%); LukED in 4 (16%); seI in 3 (12%); Agr II and hlB in 2 (8%) and Agr I, hlgCB and fnbB in 1 sample (4%). The clfA, etB, etD, fnbA, sasX, hlA, EDIN, seA, seB, seD, seH, icaB, icaC, Agr III, Agr IV and cap8 genes were not detected. Of the 25 samples, 6 showed no amplification for any gene, and one sample (33A) showed amplification for 11 genes (35% of the total genotyping panel). The sample 11A presented a genetic configuration compatible with that described in the literature for the clonal marker of USA300. Samples 33A and 33B showed a composite genotype for icaA+icaD+cap5. The diffuse presence of the toxic shock syndrome gene (TSST) found in several isolates alerts to the increase in the difficulty of treatment its association with multidrug-resistant strains. More studies are needed to understand the pathogenicity of these strains in diabetic foot infections.