title: Ampicillin and amoxicillin use and the risk of Klebsiella pneumoniae liver abscess in Taiwan.
abstract: BACKGROUND
  Klebsiella pneumoniae liver abscess (KPLA) is prevalent in East Asia. Use of amoxicillin/ampicillin may lead to overgrowth of K. pneumoniae in the intestine and predispose to KPLA. We used an animal study and nationwide population-based database to investigate the association between ampicillin/amoxicillin use and KPLA in Taiwan.
  
  
  METHODS
  In an animal study, ampicillin or sterile water was administered orogastrically in serotype K1 K. pneumoniae-colonized mice and the outcome was compared. We identified 855 cases with liver abscess and selected 3420 age- and sex-matched control subjects from the National Health Insurance Research Database. Conditional logistic regression was used to estimate the adjusted odds ratios (ORs) for the association between recent use of ampicillin/amoxicillin and KPLA.
  
  
  RESULTS
  Ampicillin administration predisposed K. pneumoniae-colonized mice to increased bacterial burden, liver abscess and necrosis, and lethality. The population-based study showed that the adjusted OR associating the use of ampicillin/amoxicillin within the past 30 days with KPLA was 3.5 (95% confidence interval, 2.5-5.1). No association was found with use in the past 31-90 days.
  
  
  CONCLUSIONS
  Ampicillin/amoxicillin therapy started within the past 30 days was associated with increased risk for KPLA. We should avoid the overuse of these antibiotics to prevent undesired disease in the endemic area.
authors.affiliation: Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Yi-Tsung
authors.initials: YT
authors.lastname: Lin
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Yeh
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.forename: Chang-Phone
authors.initials: CP
authors.lastname: Fung
mesh_terms: D000658:Amoxicillin / Q000009:adverse effects*; D000667:Ampicillin / Q000009:adverse effects*; D000818:Animals; D005260:Female; D006801:Humans; D007710:Klebsiella Infections / Q000139:chemically induced* / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology*; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000254:growth & development; D008100:Liver Abscess / Q000139:chemically induced* / Q000453:epidemiology / Q000235:genetics / Q000382:microbiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008875:Middle Aged; D012306:Risk; D012703:Serotyping / Q000379:methods; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000667:Ampicillin; D000658:Amoxicillin
keywords: Klebsiella pneumoniae; amoxicillin; ampicillin; liver abscess