title: Detection and characterization of extended-spectrum beta-lactamase-producing Enterobacteriaceae in high-risk patients in an Irish tertiary care hospital.
abstract: BACKGROUND
  Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) are Gram-negative, multi-drug-resistant organisms that are of major clinical significance among immunocompromised patients in high-risk areas in hospital settings. In Ireland, the number of ESBL-E bloodstream infections is increasing.
  
  
  OBJECTIVE
  To conduct a prevalence study of ESBL-E among immunocompromised patients in high-risk areas [intensive care unit (ICU), liver transplantation and haematology/oncology wards], characterize any ESBL genes detected by polymerase chain reaction (PCR), and perform epidemiological typing using pulsed-field gel electrophoresis (PFGE).
  
  
  METHODS
  In total, 317 non-duplicate rectal swabs from patients in high-risk wards were screened anonymously for ESBL-E carriage. Positive isolates were characterized using PCR to detect blaCTX-M, blaTEM, blaOXA-1 and blaSHV ESBL-E genes. Clonal relationships of these isolates were investigated using PFGE.
  
  
  RESULTS
  Fifty (15.8%) high-risk patients were found to harbour ESBL-E. Prevalence rates of 21.9% (N = 28), 14.3% (N = 15) and 8.3% (N = 7) of ESBL-E were isolated from patients on the liver transplantation, ICU and haematology/oncology wards, respectively. Seventy percent of ESBL-E isolates carried more than one resistance gene. Of the 25 ESBL-producing Escherichia coli isolates typed by PFGE, two pairs of two isolates demonstrated >80% homology, and four of the five ESBL-producing Enterobacter cloacae isolates typed by PFGE demonstrated >80% homology, suggesting clonal relatedness and potential cross-transmission from individual patients.
  
  
  CONCLUSIONS
  A significant proportion of the patients screened were found to be colonized with ESBL-E. Typing revealed three incidents of potential cross-infection. Therefore, timely detection of ESBL-E among patients in high-risk wards is critical for treatment and infection control.
authors: Department of Microbiology, St. Vincent's University Hospital and School of Medicine and Medical Science, University College Dublin, Dublin, Ireland. Electronic address: n.o'connell@svuh.ie.
authors: N
authors: N
authors: O'Connell
authors: Department of Microbiology, St. Vincent's University Hospital and School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
authors: D
authors: D
authors: Keating
authors: Department of Microbiology, St. Vincent's University Hospital and School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
authors: J
authors: J
authors: Kavanagh
authors: Department of Microbiology, St. Vincent's University Hospital and School of Medicine and Medical Science, University College Dublin, Dublin, Ireland.
authors: K
authors: K
authors: Schaffer
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D016867:Immunocompromised Host; D007494:Ireland; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D062606:Tertiary Care Centers; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D001618:beta-Lactamases
keywords: Bacteria; ESBL; Hospital; ICU; Resistance