Variability of antibiotic susceptibility and toxin production of Staphylococcus aureus strains isolated from skin, soft tissue, and bone related infections

Abstract

BackgroundStaphylococcus aureus is an opportunistic commensal bacterium that mostly colonizes the skin and soft tissues. The pathogenicity of S. aureus is due to both its ability to resist antibiotics, and the production of toxins. Here, we characterize a group of genes responsible for toxin production and antibiotic resistance of S. aureus strains isolated from skin, soft tissue, and bone related infections.ResultsA total of 136 S. aureus strains were collected from five different types of infection: furuncles, pyomyositis, abscesses, Buruli ulcers, and osteomyelitis, from hospital admissions and out-patients in Benin. All strains were resistant to benzyl penicillin, while 25% were resistant to methicillin, and all showed sensitivity to vancomycin. Panton-Valentine leukocidin (PVL) was the most commonly produced virulence factor (70%), followed by staphylococcal enterotoxin B (44%). Exfoliative toxin B was produced by 1.3% of the strains, and was only found in isolates from Buruli ulcers. The tsst-1, sec, and seh genes were rarely detected (≤1%).ConclusionsThis study provides new insight into the prevalence of toxin and antibiotic resistance genes in S. aureus strains responsible for skin, soft tissue, and bone infections. Our results showed that PVL was strongly associated with pyomyositis and osteomyelitis, and that there is a high prevalence of PVL-MRSA skin infections in Benin.

Toxin production and drug resistance profiles of pediatric methicillin-resistant Staphylococcus aureus isolates in Tehran

“…However, high detection frequencies of eta (11.3%) and etb (9%) were reported in Sabouni study [29] and almost the same incidence was reported in other studies [6,30,31]. This may be sensible because none of the MRSA strains in the current survey was isolated from children with skin diseases including staphylococcal scalded skin syndrome (SSSS), impetigo, or blisters.…”

“…In addition, several authors have reported that MRSA strains have become not only resistant to beta-lactam antibiotics, but they have also acquired additional resistance to non-betalactam antibiotics, especially aminoglycosides [9]. Moreover, the presence of resistance gene to methicillin may affect toxin production [6].…”

“…However, it should be pointed out that most of these factors are not always expressed and their expression occurs in specified strains and under certain conditions. For instance, S. aureus strains that produce PVL are usually associated with skin and soft-tissue infections [6].…”

The staphylococcal alpha-toxin and leukotoxins

“…The occurrence of PVL-producing strains does not exceed 2-5% among human routine clinical isolates in Europe, but can be higher in some other countries [111]. Associations with osteomyelitis and pyomyositis are now strongly suggested [117][118][119][120][121][122][123]. The locus encoding PVL is inside related bacteriophages [124][125][126][127]128].…”

<b>Prevalência e perfil de sensibilidade de staphylococcus aureus isolados em pacientes e equipe de enfermagem</b> DOI: 10.4025/cienccuidsaude.v12i3.17609

“…O Staphylococcus aureus tem ocupado lugar de destaque na etiologia das infecções hospitalares, entre outras, em função de sua alta versatilidade em adquirir resistência aos antimicrobianos (1,2,3) . A partir dos anos 40 do século XX, surgiram os primeiros registros de surtos por S. aureus resistentes à penicilina em ambiente hospitalar e nos anos 60 esta resistência se estendeu às penicilinas β-lactâmicas reconhecendo-se, então, no final daquela década, as cepas Staphylococcus aureus resistentes à meticilina (MRSA) como responsáveis por uma pandemia (1,2) .…”