title: Outbreak of New Delhi metallo-β-lactamase-1-producing Enterobacter cloacae in an acute care hospital general ward in Singapore.
abstract: BACKGROUND
  Autochthonous infections with New Delhi metallo-β-lactamase-1 (NDM-1)-producing Enterobacteriaceae have been reported in Singapore since 2011, but occurrences of nosocomial transmission have not. We report an outbreak of NDM-1-producing Enterobacter cloacae among adults admitted to an acute hospital's general ward.
  
  
  METHODS
  On detecting the index case with a culture specimen positive for NDM-1-producing E cloacae, active case finding was conducted by screening all possible patient contacts. On-site ward assessment was performed, and electronic patient medical records were reviewed to conduct a case-control study to identify factors associated with colonization.
  
  
  RESULTS
  Of 55 screened patient contacts, 3 further cases were detected, with isolates genetically related to the index case. None of these 4 cases was housed within the same cubicle. However, 3 were managed by the same medical team. Being managed by this team was positively associated with being a case (adjusted odds ratio = 15.64; 95% confidence interval, 0.91-270.27; P = .06) after adjusting for age, sex, Charlson comorbidity index score, and recent antibiotic use.
  
  
  CONCLUSIONS
  Our report suggests nosocomial transmission of NDM-1-producing E cloacae occurred via health care staff. Improvements in infection control measures, especially pertaining to staff hand hygiene practices and ward staffing, are needed to reduce the spread of highly resistant pathogens, such as NDM-1-producing Enterobacteriaceae.
authors.affiliation: Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Singapore. Electronic address: hanleyho@gmail.com.
authors.forename: Hanley J
authors.initials: HJ
authors.lastname: Ho
authors.affiliation: Infection Control Unit, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Cheng Yen
authors.initials: CY
authors.lastname: Toh
authors.affiliation: Department of Infectious Diseases, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Brenda
authors.initials: B
authors.lastname: Ang
authors.affiliation: Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore, Singapore.
authors.forename: Prabha
authors.initials: P
authors.lastname: Krishnan
authors.affiliation: National Public Health Laboratory, Ministry of Health, Singapore, Singapore; Department of Laboratory Medicine, National University Health System, Singapore, Singapore.
authors.forename: Raymond T P
authors.initials: RT
authors.lastname: Lin
authors.affiliation: National Public Health Laboratory, Ministry of Health, Singapore, Singapore.
authors.forename: My-Van
authors.initials: MV
authors.lastname: La
authors.affiliation: Department of Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Singapore; Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.
authors.forename: Angela
authors.initials: A
authors.lastname: Chow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D004196:Disease Outbreaks; D016972:Enterobacter cloacae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D005260:Female; D063373:Hand Hygiene; D006761:Hospitals; D006801:Humans; D017053:Infection Control; D008297:Male; D008875:Middle Aged; D010362:Patients' Rooms; D012846:Singapore / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases; C552864:beta-lactamase NDM-1
keywords: Enterobacter cloacae; Infection control; New Delhi metallo-β-lactamase-1; Outbreaks; Pathogen transmission; Singapore