Universal hospital admission screening for carbapenemase-producing organisms in a low-prevalence setting

J Antimicrob Chemother. 2016 Dec;71(12):3556-3561. doi: 10.1093/jac/dkw309. Epub 2016 Aug 11.


Background: Carbapenemase-producing Enterobacteriaceae (CPE) are an emerging threat for healthcare providers worldwide.

Objectives: To determine CPE carriage rates and risk factors in an unselected hospital cohort at the time of admission.

Methods: We approached 4567 patients within 72 h of admission to provide a rectal swab and answer a questionnaire on risk factors for carriage. Rectal swabs were cultured for carbapenem-resistant organisms on chromogenic and non-chromogenic agar, and tested for carbapenemase production by PCR (Check-Direct CPE). The study was approved by the NHS Research Ethics Committee.

Results: Only 6 CPE were cultured from 5 (0.1%) of 4006 patients who provided a rectal swab; only 1 was cultured using non-chromogenic media. An additional 76 culture-negative rectal swabs were initially PCR positive, but none grew a carbapenem-resistant organism despite enrichment culture and only two were positive when retested several months later by Check-Direct and a second PCR assay (Cepheid GeneXpert® Carba-R). A modified Ct cut-off of <35 would have resolved these apparent false-positives. 40% of patients had a risk factor that should prompt screening and pre-emptive isolation as defined by UK CPE guidelines but only 8.1% and 20.2% of these patients had been screened and pre-emptively isolated by clinical teams, respectively. Overseas hospitalization was the only significant risk factor for CPE carriage (P < 0.001, OR 64.3, 95% CI 7.3-488.5).

Conclusions: This study highlights a very low carriage rate of CPE. Hospitalization abroad is the most important risk factor to guide admission screening in this low-prevalence setting.

MeSH terms

  • Adult
  • Bacterial Proteins / analysis*
  • Bacteriological Techniques
  • Carrier State / diagnosis
  • Carrier State / epidemiology
  • Carrier State / microbiology
  • Diagnostic Tests, Routine / methods*
  • Enterobacteriaceae / enzymology*
  • Enterobacteriaceae / isolation & purification
  • Enterobacteriaceae Infections / diagnosis*
  • Enterobacteriaceae Infections / epidemiology
  • Enterobacteriaceae Infections / microbiology*
  • Female
  • Genotyping Techniques
  • Hospitals
  • Humans
  • Male
  • Mass Screening / standards
  • Mass Screening / statistics & numerical data
  • Middle Aged
  • Polymerase Chain Reaction
  • Prevalence
  • Rectum / microbiology
  • Surveys and Questionnaires
  • United Kingdom
  • beta-Lactamases / analysis*


  • Bacterial Proteins
  • beta-Lactamases
  • carbapenemase