title: Outbreak of Shewanella algae and Shewanella putrefaciens infections caused by a shared measuring cup in a general surgery unit in Korea.
abstract: OBJECTIVE
  To control an outbreak of Shewanella algae and S. putrefaciens infections by identifying the risk factors for infection and transmission.
  
  
  METHODS
  Matched case-control study.
  
  
  METHODS
  A university-affiliated tertiary acute care hospital in Seoul, Republic of Korea, with approximately 1,600 beds.
  
  
  METHODS
  From June 20, 2003, to January 16, 2004, a total of 31 case patients with Shewanella colonization or infection and 62 control patients were enrolled in the study.
  
  
  METHODS
  Requirement to use single-use measuring cups and standard precautions (including hand washing before and after patient care and use of gloves).
  
  
  RESULTS
  S. algae or S. putrefaciens was isolated from blood, for 9 (29.0%) of 31 patients who acquired one of the organisms; from bile, for 8 (25.8%), and from ascitic fluid, for 8 (25.8%). The attack rate of this outbreak was 5.8% (31 patients infected or colonized, of 534 potentially exposed on ward A) and the pathogenicity of the two species together was 77.4% (24 patients infected, of 31 who acquired the pathogens). The estimated incubation period for Shewanella acquisition was 3-49 days. Using logistic analysis, we identified the following risk factors: presence of external drainage catheters in the hepatobiliary system (odds ratio [OR], 20; P < .001), presence of hepatobiliary disease (OR, 6.4; P < .001), admission to the emergency department of the hospital (OR, 2.9; P = .039), wound classification of "contaminated" or "dirty or infected" (OR, 16.5; P = .012), an American Society of Anesthesiologists score of 3 or higher (OR, 8.0; P = .006), duration of stay in ward A (OR, 1.1; P < .001), and, for women, an age of 60-69 years (OR, 13.3; P = .028). A Shewanella isolate was recovered from the surface of a shared measuring cup, and 12 isolates of S. algae showed the same pulsed-field gel electrophoresis pattern.
  
  
  CONCLUSIONS
  This Shewanella outbreak had a single-source origin and spread by contact transmission via a contaminated measuring cup. Shewanella species are emerging as potentially serious human pathogens in hospitals and could be included in hospital infection surveillance systems.
authors.affiliation: Department of Infection Control Service, Seoul National University Hospital, Seoul, Republic of Korea .
authors.forename: Hyang Soon
authors.initials: HS
authors.lastname: Oh
authors.forename: Kyung Ah
authors.initials: KA
authors.lastname: Kum
authors.forename: Eui-Chong
authors.initials: EC
authors.lastname: Kim
authors.forename: Hoan-Jong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Kang Won
authors.initials: KW
authors.lastname: Choe
authors.forename: Myoung Don
authors.initials: MD
authors.lastname: Oh
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D004196:Disease Outbreaks; D004866:Equipment Contamination; D004865:Equipment and Supplies, Hospital; D005260:Female; D013502:General Surgery; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000209:etiology / Q000382:microbiology / Q000635:transmission; D006746:Hospital Bed Capacity, 500 and over; D006757:Hospital Units; D006801:Humans; D007723:Korea; D008297:Male; D008875:Middle Aged; D020592:Shewanella / Q000145:classification / Q000302:isolation & purification*; D020614:Shewanella putrefaciens / Q000302:isolation & purification*