Molecular typing, virulence traits and antimicrobial resistance of diabetic foot staphylococci

Abstract

BackgroundDiabetes mellitus is a major chronic disease that continues to increase significantly. One of the most important and costly complications of diabetes are foot infections that may be colonized by pathogenic and antimicrobial resistant bacteria, harboring several virulence factors, that could impair its successful treatment. Staphylococcus aureus is one of the most prevalent isolate in diabetic foot infections, together with aerobes and anaerobes.MethodsIn this study, conducted in the Lisbon area, staphylococci isolated (n = 53) from diabetic foot ulcers were identified, genotyped and screened for virulence and antimicrobial resistance traits. Genetic relationship amongst isolates was evaluated by pulsed-field-gel-electrophoresis with further multilocus sequence typing of the identified pulsotypes. PCR was applied for detection of 12 virulence genes and e-test technique was performed to determine minimal inhibitory concentration of ten antibiotics.ResultsAmong the 53 isolates included in this study, 41 Staphylococcus aureus were identified. Staphylococcal isolates were positive for intercellular adhesins icaA and icaD, negative for biofilm associated protein bap and pantone-valentine leucocidin pvl. S. aureus quorum sensing genes agrI and agrII were identified and only one isolate was positive for toxic shock syndrome toxin tst.36 % of staphylococci tested were multiresistant and higher rates of resistance were obtained for ciprofloxacin and erythromycin. Clonality analysis revealed high genomic diversity and numerous S. aureus sequence types, both community- and hospital-acquired, belonging mostly to clonal complexes CC5 and C22, widely diffused in Portugal nowadays.ConclusionsThis study shows that diabetic foot ulcer staphylococci are genomically diverse, present resistance to medically important antibiotics and harbour virulence determinants. These properties suggest staphylococci can contribute to persistence and severity of these infections, leading to treatment failure and to the possibility of transmitting these features to other microorganisms sharing the same niche. In this context, diabetic patients may become a transmission vehicle for microorganisms’ clones between community and clinical environments.

Association between agr group, genetic background, virulence factors and disease types of Staphylococcus aureus isolated from Chinese children

“…Two surface components have been implicated in biofilm formation by S. aureus, the product of the icaADBC operon and the Bap [42]. Our data were in agreement with previous studies, which have demonstrated that biofilm genes icaA/icaC/icaD were present in all isolates, whereas bap was always missing [43,44]. The relatively low detection rate of bap indicates that the ica-dependent mechanism might be primarily responsible for adhesion and biofilm production in S. aureus strains [45].…”

Pexiganan in Combination with Nisin to Control Polymicrobial Diabetic Foot Infections

“…In this study, we used the biofilm-producing DFI strains Staphylococcus aureus Z25.2 and Pseudomonas aeruginosa Z25.1, co-isolated from a diabetic foot ulcer. The strains were selected from a bacterial collection obtained from patients with Diabetes mellitus and infected foot ulcers, as described in a previous study by Mendes et al [6] and characterized by Mottola et al [64]. All isolates were stored at -80 • C in buffered peptone water supplemented with 20% (v/v) of glycerol.…”

Correlation of Virulence Determinants of Staphylococcus aureus to the Severity of Diabetic Foot Ulcers in a Tertiary Care Centre, Egypt

“…Both were mainly manifested in more severe infections in grades III and IV and the results were stastically significant. tst gene was detected in only one isolate from diabetic foot ulcer (2.4%) in Mottola et al study [34].…”

“…coa and clfA genes were positive in 33 (97.1%) and 32 (94.1%) isolates respectively with nearly similar prevalence in all studied grades of diabetic foot infections. Mottola et al [34] found that all isolates were coa positive but only 70% were clfA positive.…”

“…It is encoded by the lukS-PV and lukF-PV genes, and can induce damage of leukocytes [36]. A previous meta-analysis confirmed that there was an association between PVL and S. aureus skin infections, and that was not shown in invasive infections caused by S. aureus [37] All the S. aureus strains isolated by Mottola et al [34] from diabetic foot ulcers were negative for pvl gene.…”