Detection of Epidemic USA300 Community-Associated Methicillin-Resistant Staphylococcus aureus Strains by Use of a Single Allele-Specific PCR Assay Targeting a Novel Polymorphism of Staphylococcus aureus pbp3

Abstract

In recent years, the dramatic increase in community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections has become a significant health care challenge. Early detection of CA-MRSA is important because of its increased virulence associated with the arginine catabolic mobile element (ACME), Panton-Valentine leukocidin (PVL), and other toxins that may contribute to disease severity. In particular, the USA300 epidemic clone has emerged and now represents the cause of as much as 98% of CA-MRSA skin and soft tissue infections in the United States. Current diagnostic assays used to identify CA-MRSA strains are based on complex multiplex PCRs targeting the staphylococcal cassette chromosome mec (SCCmec) DNA junction, a multitude of genes, and noncoding DNA fragments or on a number of lengthy sequencetyping methods. Here, two nucleotide polymorphisms, G88A and G2047A, that were found to be in strict linkage disequilibrium in the S. aureus penicillin-binding protein 3 (pbp3) gene were also found to be highly associated with the USA300 clone of CA-MRSA. Clinical isolates that contained this pbp3 allele were also positive for the presence of SCCmec type IV, the ACME, and the PVL toxin gene and matched the t008 or t121 molecular spa types, which are associated specifically with the USA300 CA-MRSA clone. A single allele-specific PCR targeting the G88A polymorphism was developed and was found to be 100% sensitive and specific for the detection of USA300 CA-MRSA and 91.5% sensitive and 100% specific for the detection of all CA-MRSA isolates in this study.

In VitroInhibitory and Cytotoxic Activity of MFM 501, a Novel Codonopsinine Derivative, against Methicillin-ResistantStaphylococcus aureusClinical Isolates

“…Nevertheless, MFM 501 did display a weak inhibitory activity towards a MRSA reference strain, ATCC 700699, with MIC value of 250 μ g/mL. This particular strain (ATCC 700699) has been described to exert intermediate resistance against vancomycin [ 29 ] while BAA-1556 is a CA-MRSA strain that causes more than 98% of skin and soft tissue infection in the United States [ 30 ]. The MIC results suggest that MFM 501 has inhibition ability against both CA- and hospital-acquired- (HA-) MRSA but is less effective against vancomycin-intermediate-resistant S. aureus (VISA).…”

USA300 methicillin-resistant Staphylococcus aureus in Zurich, Switzerland between 2001 and 2013

“…While PFGE profiles are still used in some studies as single marker for USA300 (ComoSabetti et al, 2009), most groups have recently included additional genetic markers to further specify USA300 strains. Commonly used markers include SCCmec type IV, spa type t008, the presence of PVL and the ACME arc gene cluster, macrolide resistance and various combinations of these markers (Chadwick et al, 2013;Diep et al, 2006Diep et al, , 2008Larsen et al, 2009;Tattevin et al, 2012;Tenover et al, 2006), which renders the comparison of different studies on USA300 difficult. We therefore decided to use a stringent definition for USA300 including the specific PFGE profile, spa-type and the presence of the ACME arc gene cluster and PVL genes but we have also included strains that only partially fulfilled our criteria and designated these USA300 variants and USA300-49.…”

Antimicrobial resistance in wildlife

“…The methicillin‐resistant strain of S. aureus (MRSA), USA300, appears to have caused a strong increase in severe cutaneous infections observed in the USA in the 2000s (Chadwick et al . ). It is an example of bacteria in which AMR and virulence are associated.…”

“…As an illustration, the different steps leading to methicillin resistance acquisition in Staphylococcus aureus are associated with virulence modifications (Cameron, Howden & Peleg 2011). The methicillin-resistant strain of S. aureus (MRSA), USA300, appears to have caused a strong increase in severe cutaneous infections observed in the USA in the 2000s (Chadwick et al 2013). It is an example of bacteria in which AMR and (1) Decrease in the membrane permeability to a drug.…”