Colonisation with ESBL-producing and carbapenemase-producing Enterobacteriaceae, vancomycin-resistant enterococci, and meticillin-resistant Staphylococcus aureus in a long-term care facility over one year

BMC Infect Dis. 2015 Apr 1;15:168. doi: 10.1186/s12879-015-0880-5.

Abstract

Background: This study examined colonisation with and characteristics of antimicrobial-resistant organisms among residents of a long-term care facility (LTCF) over one year, including strain persistence and molecular diversity among isolates of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae.

Methods: Sixty-four residents of a LTCF were recruited (51 at baseline, 13 during the year). Data on dependency levels, hospitalisations, and antimicrobial prescribing were collected. Nasal and rectal swabs and catheter urine specimens were examined quarterly, using chromogenic agars, for ESBL-producing Enterobacteriaceae, carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE), and meticillin-resistant S. aureus (MRSA). All ESBL-producing E. coli (ESBL-EC) were characterised by pulsed-field gel electrophoresis (PFGE) and PCR to assess for sequence type (ST) ST131, its resistance-associated H30 and H30-Rx subclones, and blaCTX-M, blaTEM, blaSHV, and blaOXA-1.

Results: The overall number of residents colonised, by organism, was as follows: ESBL-EC, 35 (55%); MRSA, 17 (27%); ESBL-producing K. pneumoniae (ESBL-KP), 5 (8%); VRE, 2 (3%) and CPE, 0 (0%). All 98 ESBL-EC isolates were H30-Rx ST131, with bla CTX-M-group 1. By PFGE, a group of 91 ESBL-EC (from 33 participants) had ≥85% similar profiles and resembled UK epidemic strain A/ international pulsotype PFGE812. Sequential ESBL-EC from individual residents were closely related. Six ESBL-KP isolates, from five participants, had bla CTX-M-group 1 and by PFGE were closely related. Colonisation with ESBL and MRSA was associated with location within the LTCF and previous exposure to antimicrobials.

Conclusions: Among LTCF residents, colonisation with ESBL-EC and MRSA was common. All ESBL-EC were H30-Rx ST131, consistent with clonal dissemination.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Bacterial Proteins
  • Carrier State / epidemiology*
  • Carrier State / microbiology
  • Electrophoresis, Gel, Pulsed-Field
  • Enterobacteriaceae / isolation & purification*
  • Enterobacteriaceae / physiology
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / microbiology
  • Escherichia coli / isolation & purification*
  • Escherichia coli / physiology
  • Escherichia coli Infections / epidemiology
  • Escherichia coli Infections / microbiology
  • Female
  • Gram-Negative Bacterial Infections / epidemiology*
  • Gram-Negative Bacterial Infections / microbiology
  • Gram-Positive Bacterial Infections / epidemiology*
  • Gram-Positive Bacterial Infections / microbiology
  • Humans
  • Klebsiella Infections / epidemiology
  • Klebsiella Infections / microbiology
  • Klebsiella pneumoniae / isolation & purification
  • Klebsiella pneumoniae / physiology
  • Long-Term Care
  • Male
  • Methicillin
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Methicillin-Resistant Staphylococcus aureus / physiology
  • Molecular Epidemiology
  • Nursing Homes*
  • Polymerase Chain Reaction
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology
  • Vancomycin-Resistant Enterococci / isolation & purification*
  • Vancomycin-Resistant Enterococci / physiology
  • beta-Lactamases

Substances

  • Bacterial Proteins
  • beta-lactamase TEM-3
  • beta-Lactamases
  • carbapenemase
  • Methicillin