Distribution of meticillin-resistant Staphylococcus aureus spa types isolated from health-care workers and patients in a Scottish university teaching hospital

Abstract

Our study was aimed at comparing the meticillin-resistant Staphylococcus aureus (MRSA) strains isolated from an anonymous group of health-care workers (HCWs) with those obtained from patient samples during a 3-month time interval. We employed spa typing and virulence gene profiling to characterize the MRSA strains. Our data revealed that a total of 14 discrete spa types were circulating in both patients and HCWs. The t032 spa type, characteristic of EMRSA15 and the Barnim EMRSA ST 22 clones, accounted for over 70 % of isolates, and was equally distributed between patients and HCW groups. In addition, a number of epidemic and sporadic strains were identified, which highlighted the diversity of spa types that can be found within a health-care setting. Virulence profiling for the carriage of 7 genes by the 14 different spa types demonstrated that 10 types carried the fnbA, cna, sdrE, hlg and ica virulence factors. We concluded that there was no significant difference between the MRSA strains found circulating in the patients and the HCWs, and noted that the dominant spa types carried an identical set of virulence genes that included the key adhesins fnbA, cna and sdrE. INTRODUCTIONStaphylococcus aureus is an important human pathogen and is one of the most significant causes of health-careassociated infections in the UK. In an attempt to control the high mortality and morbidity of systemic meticillinresistant S. aureus (MRSA) infections, techniques have been developed to analyse the genetic relatedness of different strains and help inform infection control policies. The single most important identification method is PFGE; however, the complexity, cost and lack of inter-laboratory standardization have led to the appearance of alternative methods (Deurenberg et al., 2007). For long-term global studies on the evolution of strains, multilocus sequence typing is the most commonly used technique (Enright & Spratt, 1999), while for short-term studies on molecular evolution and nosocomial outbreaks, spa typing has proved an excellent tool (Koreen et al., 2004; Malachowa et al., 2005; Shopsin et al., 1999).Alongside the development of sequenced-based typing methods, attention has become focused on the comparison of different MRSA genomes. In particular, the number of studies on the distribution of genes that are directly involved in causing disease has increased (Kuhn et al., 2006;Nashev et al., 2004; Peacock et al., 2002). These genes encode a variety of products that are referred to as virulence factors. Examples include PVL, a toxin linked to the occurrence of necrotizing pneumonia (Brown et al., 2009;Labandeira-Rey et al., 2007); ETA, the toxin responsible for scalded skin syndrome (Amagai et al., 2000); and CNA, the collagen-binding protein that is associated with osteomyelitis (Elasri et al., 2002). , Peacock et al. (2002 compared the distribution of 33 putative virulence factors amongst S. aureus strains isolated from the nasal passages of blood donors and strains responsible for invasive disease. This work suggeste...

A multinational study of colonization with extended spectrum β-lactamase-producing Enterobacteriaceae in healthcare personnel and family members of carrier patients hospitalized in rehabilitation centres

“…sharing food, hugging). These findings differ from those regarding methicillin‐resistant S. aureus , which showed transmission in both the community settings to FMs and other contacts, as well as to (and from) HCWs in the healthcare settings. The difference between methicillin‐resistant S. aureus and EPE may be a result of their different colonization sites, degree of environmental survivability or other unclear biological factors.…”

Enhanced Discrimination of Highly Clonal ST22-Methicillin-Resistant Staphylococcus aureus IV Isolates Achieved by Combining spa , dru , and Pulsed-Field Gel Electrophoresis Typing Data

“…ST22-MRSA-IV has also been identified among patients with hospital-acquired (HA) MRSA infections (11,42,43,60,63) and CA-MRSA infections (5,15,32,49) in several countries, among health care workers (2,55), and among companion animals (3,18,36,41).…”

“…In Ireland, ST22-MRSA-IV isolates belong to a PFGE group described as pulsed-field group 01 (PFG-01) and exhibit the non-multiantibiotic-resistant antibiogram-resistogram (AR) type AR06 or closely related AR patterns (47). ST22-MRSA-IV isolates also yield a limited number of spa types following DNA sequencing of the protein A (spa) gene (27,55).…”

Environmental Contamination in the Hospital as a Possible Source for Nosocomial Infection with Methicillin-Resistant Staphylococcus aureus

“…Although the hospital environment was identified as a possible source of nosocomial MRSA transmission, HCWs could not be excluded as a clinically relevant source, because HCWs still carried strains with significant numbers of virulence genes. A study by Soliman et al 6 from 2009 demonstrated that MRSA isolated from the noses of HCWs and from nasal and blood cultures from patients had the same genetic background {spa type t032 /ST22), including carriage of most virulence genes. In another study, it was found that, of the strains recovered from 11 patients who had MRSA infection or colonization, 7 strains shared the same PFGE pattern, whereas strains from 2 patients and 1 HCW had identical PFGE patterns.…”