Publications (2)9.01 Total impact
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Article: Shared reservoir of ccrB gene sequences between coagulase-negative staphylococci and methicillin-resistant Staphylococcus aureus.
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ABSTRACT: OBJECTIVES: Methicillin resistance in Staphylococcus aureus and coagulase-negative staphylococci (CoNS) is caused by expression of the low-affinity penicillin-binding protein (PBP) 2a encoded by the mecA gene. This gene is carried on the staphylococcal cassette chromosome mec (SCCmec) of which several types and subtypes have been described. CoNS and S. aureus share SCCmec types and it has been suggested that CoNS are a potential reservoir of mecA for S. aureus. Evidence for this is mainly based on PCR typing of SCCmec or on sequence-based methods including only a limited number of strains. In this study, we determined the genetic relatedness of ccrB sequences contained in SCCmec elements of a spatio-temporally diverse and comprehensive collection of methicillin-resistant CoNS and S. aureus. METHODS: Part of the ccrB genes of 367 methicillin-resistant CoNS and 94 methicillin-resistant S. aureus (MRSA) were sequenced and compared. RESULTS: The data revealed that 92 of 94 (98%) MRSA isolates carried ccrB genes, involving different ccrB alleles, which were indistinguishable from ccrB genes of methicillin-resistant CoNS. In total, 273 of 367 (74%) CoNS shared ccrB gene sequences with MRSA. CONCLUSIONS: The high rate of identical ccrB sequences in a geographically, temporally and genotypically diverse set of S. aureus and CoNS isolates indicates frequent horizontal transfer of SCCmec between CoNS and S. aureus, which may have contributed to the emergence of MRSA.Journal of Antimicrobial Chemotherapy 04/2013; · 5.07 Impact Factor -
Article: The recombinase IntA is required for excision of esp-containing ICEEfm1 in Enterococcus faecium.
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ABSTRACT: Comparative genome analysis of Enterococcus faecium recently revealed that a genomic island containing the esp gene, referred to as the esp-containing pathogenicity island (esp PAI), can be transferred by conjugation and contains a partial Tn916-like element and an integrase gene, intA. Here, we characterize the role of intA in the excision of the esp PAI. An intA insertion-deletion mutant in E. faecium E1162 (E1162ΔintA) was constructed and in trans complemented with wild-type intA (E1162ΔintA::pEF30). Circular intermediates (CI) of excised esp PAI were determined using inverse PCR analysis on purified chromosomal DNA from strains E1162, E1162Δesp, E1162ΔintA, and E1162ΔintA::pEF30. In E1162 and E1162Δesp, CI of the esp PAI were detected. No CI were detected in E1162ΔintA, while in the complemented strain E1162ΔintA::pEF30 CI formation was restored, indicating that intA is essential for excision and subsequent mobilization of the esp-containing genomic island in E. faecium. Based on the fact that this island can be mobilized and is self-transmissible, we propose to change the name of the esp PAI to ICEEfm1.Journal of bacteriology 02/2011; 193(4):1003-6. · 3.94 Impact Factor
