title: Exploring the epidemiology of carbapenem-resistant Gram-negative bacteria in west London and the utility of routinely collected hospital microbiology data.
abstract: OBJECTIVE
  The objective of this study was to identify carbapenem-resistant organisms using routinely collected local microbiology data and describe the epidemiology of carbapenem resistance in two London teaching hospitals.
  
  
  METHODS
  Data on inpatients infected or colonized with Gram-negative organisms between March 2009 and February 2012 were extracted. A computer algorithm was developed incorporating internationally recognized criteria to distinguish carbapenem-resistant organisms. Multivariable analysis was conducted to identify factors associated with infection or colonization with carbapenem-resistant organisms. Binomial regression was performed to detect changes in resistance trends over time.
  
  
  RESULTS
  Yearly incidence of carbapenem resistance was observed to be increasing, with significant increasing trends in Acinetobacter baumannii (47.1% in 2009-10 to 77.2% in 2011-12; P<0.001) and Enterobacter spp. (2.2% in 2009-10 to 11.5% in 2011-12; P<0.001). Single-variable and multivariable analysis demonstrated differences in the proportion of carbapenem-resistant isolates across all variables investigated, including age, sex and clinical specialty; in the latter organism-specific niches were identified. Patients in the youngest age group (16-24 years old) had the highest odds of being infected or colonized with carbapenem-resistant isolates of Escherichia coli, Klebsiella spp. or Pseudomonas aeruginosa. Furthermore, proportions of carbapenem-resistant organisms differed between the hospitals.
  
  
  CONCLUSIONS
  Carbapenem resistance is an emerging problem within the UK inpatient healthcare setting. This is not an issue confined to the Enterobacteriaceae and fine-resolution surveillance is needed to identify at-risk groups. Regular analysis of routinely collected data can provide insight into the evolving carbapenem-resistance threat, with the ability to inform efforts to prevent the spread of resistance.
authors.affiliation: The National Centre for Infection Prevention and Management, Imperial College London, Du Cane Road, London W12 0NN, UK rachel.freeman@phe.gov.uk.
authors.forename: R
authors.initials: R
authors.lastname: Freeman
authors.affiliation: The National Centre for Infection Prevention and Management, Imperial College London, Du Cane Road, London W12 0NN, UK Imperial College Healthcare NHS Trust, Du Cane Road, London W12 0HS, UK.
authors.forename: L S P
authors.initials: LS
authors.lastname: Moore
authors.affiliation: Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK.
authors.forename: A
authors.initials: A
authors.lastname: Charlett
authors.affiliation: Imperial College Healthcare NHS Trust, Du Cane Road, London W12 0HS, UK.
authors.forename: H
authors.initials: H
authors.lastname: Donaldson
authors.affiliation: The National Centre for Infection Prevention and Management, Imperial College London, Du Cane Road, London W12 0NN, UK Imperial College Healthcare NHS Trust, Du Cane Road, London W12 0HS, UK.
authors.forename: A H
authors.initials: AH
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D005260:Female; D006090:Gram-Negative Bacteria / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006784:Hospitals, Teaching; D006801:Humans; D008131:London / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D055815:Young Adult; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems
keywords: microbiology; resistance; surveillance