Staphylococcus aureus Virulence Factors Associated With Infected Skin Lesions

Abstract

To evaluate Staphylococcus aureus isolates from infected skin lesions for their potential to produce immune system-modulating toxins and to correlate these with white blood cell (WBC) counts associated with these lesions. Design: Specimens were obtained for bacterial culture and gram staining from 105 infected skin lesions, and the number of WBCs per low-power field (LPF) was determined. Chromosomal DNA was prepared from 84 bacterial isolates and subjected to real-time polymerase chain reaction analysis to determine the presence of genes encoding potential immunomodulating toxins. Bacterial populations were divided into 2 groups: those associated with low WBC counts (0-5 WBCs/LPF) and those with high WBC counts (Ͼ 5 WBCs/LPF). We applied 2 statistical analyses to compare the toxin gene profiles associated with WBC counts on initial swab for culture. Patients: Samples were obtained from patients at a single geographic location. Results: A higher than expected percentage of bacteria capable of producing the exfoliative toxins A and/or B (ETA and/or ETB) and Panton-Valentine leukocidin (PVL) was seen in all skin lesions infected with S aureus without regard to WBC count with initial cultures. Comparison of the toxins associated with the low WBC group vs the high WBC group showed that low WBC counts were associated with ETA and ETB, while high WBC counts were associated with PVL and toxic shock syndrome toxin. There were no differences in the clinical appearance of the lesions between groups. Conclusions: Staphylococcus aureus virulence factors ETA, ETB, and PVL are associated with WBC counts from infected skin lesions. The exact role they play in affecting the WBC counts remains to be determined.

Complementary Analysis of the Vegetative Membrane Proteome of the Human Pathogen Staphylococcus aureus

“…Peptides originating from the proteinase K-chymotrypsin method (shaving approach) were separated only in one dimension but over a long LC gradient that was run in six replicates (number of protein identifications in single replicates: 121, 118, 112, 122, 132, and 135) approaching a saturation in the number of protein identifications. 2 Detailed information on the protein identification for each of the three techniques introduced is provided in supplemental Tables S4 -S6. Furthermore the corresponding Scaffold files and results of single replicates including MS/MS spectra for all peptide identifications are available upon request.…”

“…The human pathogenic bacterium Staphylococcus aureus causes a wide variety of diseases ranging from minor skin infections (1,2) to critical endocarditis (3,4) and sepsis (5). The spreading of multiresistant S. aureus strains and the increasing number of lethal infections worldwide is most alarming.…”

Community-acquired methicillin-resistant Staphylococcus aureus: community transmission, pathogenesis, and drug resistance

“…Exfoliative toxins are proteinase from S. aureus, which digest desmoglein 1, resulting in exfoliation of the epidermis cells [190]. Exfoliative toxin involves ETA, ETB, and ETD.…”

Combination therapy with iron chelation and vancomycin in treating murine staphylococcemia

“…Staphylococcus aureus , a persistent nasal colonizer in approximately one-third of the human population [1], causes infections ranging from superficial skin lesions to life-threatening syndromes such as endocarditis, osteomyelitis, toxic shock, and sepsis [2–4]. Indeed, S. aureus is the second leading cause of healthcare-associated bacteremia, accounting for ~13 % of such infections.…”