Clinical outcomes and treatment approach for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections in Israel

Eur J Clin Microbiol Infect Dis. 2017 Jan;36(1):153-162. doi: 10.1007/s10096-016-2789-3. Epub 2016 Sep 27.

Abstract

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are increasingly documented worldwide. We recently identified two major CA-MRSA clones in Israel: USA300 and t991. Here, we assessed clinical outcomes by CA-MRSA clones and the physicians' treatment approach to CA-MRSA infections. All community-onset, clinical MRSA isolates detected during 2011-2013 by Maccabi Healthcare Services were collected and characterized phenotypically and genotypically; data were collected retrospectively from electronic medical records. Of 309 patients with MRSA infections, 64 were identified as CA-MRSA (21 %). Of the CA-MRSA infections, 72 % had skin and soft tissue infections (SSTIs), 38 % were Panton-Valentine leukocidin (PVL)+, the major clone being USA300 (n = 13, 54 %). Of PVL- isolates (n = 40, 62 %), t991 was the major clone. Age was the only predictor for PVL+ CA-MRSA infection (p < 0.001). Patients with PVL+ CA-MRSA had higher incidence of SSTI recurrences (1.061 vs. 0.647 events per patient/per year, p < 0.0001) and were more likely to have the SSTI drained (64 % vs. 21 %, p = 0.003) when compared to PVL- CA-MRSA. USA300 was more common among adults, while t991 was more common among children (p = 0.002). The physician's referral to culture results and susceptibility were the only predictors of appropriate antibiotic therapy (p < 0.001). However, only a minority of physicians referred to culture results, regardless of subspecialties. PVL+ CA-MRSA isolates caused significantly more recurrences of SSTIs and increased the need for drainage compared with PVL- isolates. Physicians' awareness of CA-MRSA as a cause of SSTIs in the community was suboptimal. Culturing of pus-producing SSTIs is crucial for providing adequate antimicrobials and elucidating MRSA epidemiology.

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / therapeutic use*
  • Bacterial Toxins / genetics
  • Child
  • Child, Preschool
  • Community-Acquired Infections / drug therapy*
  • Community-Acquired Infections / epidemiology
  • Community-Acquired Infections / microbiology*
  • Exotoxins / genetics
  • Female
  • Genotype
  • Humans
  • Infant
  • Infant, Newborn
  • Israel / epidemiology
  • Leukocidins / genetics
  • Male
  • Methicillin-Resistant Staphylococcus aureus / classification
  • Methicillin-Resistant Staphylococcus aureus / genetics
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Middle Aged
  • Molecular Typing
  • Practice Patterns, Physicians'*
  • Recurrence
  • Retrospective Studies
  • Risk Factors
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology*
  • Treatment Outcome
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Bacterial Toxins
  • Exotoxins
  • Leukocidins
  • Panton-Valentine leukocidin