Widespread Skin and Soft-Tissue Infections Due to Two Methicillin-Resistant Staphylococcus aureus Strains Harboring the Genes for Panton-Valentine Leucocidin

Abstract

Infections caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging as a major public health problem. CA-MRSA has been associated previously with skin and soft-tissue infection (SSTI) and with carriage of staphylococcal cassette chromosome mec (SCCmec) type IV and the Panton-Valentine leucocidin (PVL) virulence factor. To assess the clonal distribution of PVL-carrying strains and the association with SSTI in the San Francisco Bay area, we surveyed six collections of S. aureus isolates-671 isolates in all-collected between 1997 and 2002 originating from inpatient and outpatient clinical specimens and from a community-based sampling. Isolates were genotyped by pulsed-field gel electrophoresis, multilocus restriction fragment typing, and multilocus sequence typing and assayed for the PVL virulence factor. The S. aureus populations showed a high proportion of PVL-carrying strains, with frequencies ranging up to 70% in MRSA isolated from jail inmate patients and 69% in MRSA from patients receiving surgical treatment at an outpatient clinic specializing in treating SSTIs. PVL-carrying isolates were identified in nine clonal groups, but 88.5% of the PVL-carrying MRSA isolates belonged to only two clonal groups. These two clonal groups carried the SCCmec type IV resistance determinant and were more likely than other clonal groups to be recovered from SSTI sites than from other sites (P < 0.0001). There is evidence of clonal replacement over the period from 1999 to 2002, with one of these two clonal groups being supplanted by the other.

Controversies in host defense against surgical site infection

“…The dissemination of this particular organism within communities such as army bases, schools and other crowded institutions such as hospitals is a worrying but well-described new disease entity, known commonly as community-acquired MRSA (CA-MRSA). CA-MRSA levels are on the rise and exhibit increased virulence as compared with other community-acquired S. aureus species [4][5][6]. Therapies such as vancomycin, a glycopeptide with well-recognized but limited toxic side effects, usually provide effective coverage against MRSA.…”

Antibiotic resistance of Staphylococcus-like organisms isolated from a recreational sea beach on the southern coast of the Baltic Sea as one of the consequences of anthropogenic pressure

“…The antibiotic resistance patterns of Staphylococcus from clinical samples have been extensively studied (Torimiro et al 2005, Stotts et al 2005; the study by Diep et al (2004) showed that an antibiotic-resistant strain of these pathogens, mainly MRSA, has significantly increased in recent years. According to Werckenthin et al (2001) antibiotic resistance is carried on plasmids and transposons, which can pass from one staphylococcal species to another.…”

Methicillin-Resistant Staphylococcus aureus Infections in Uppsala County, Sweden

“…However, fatal cases of CA-MRSA infections in children without identified risk have been reported [6]. CA-MRSA is genetically different from HCA-MRSA, expressing different virulence factors but is also sharing common attributes with HCA-MRSA [7]. CA-MRSA often expresses the toxin PantonValentine leukocidin (PVL) gene and is generally not multidrug resistant [3].…”