title: Extended-spectrum beta-lactamase-producing bacteria are not detected in supragingival plaque samples from human fecal carriers of ESBL-producing Enterobacteriaceae.
abstract: BACKGROUND
  The prevalence of infections caused by Cefotaximase-Munich (CTX-M)-type extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) has rapidly increased during the past 15 years. Enterobacteriaceae are commonly found in the gastrointestinal tract and long-term intestinal carriage is considered important for the spread of ESBL and as a source of clinical infections. Oral biofilm such as supragingival plaque is known to contain numerous antibiotic resistance determinants and may also represent a poorly investigated site for ESBL carriage and further spread.
  
  
  OBJECTIVE
  To investigate possible carriage of ESBL-producing bacteria in supragingival plaque of known fecal carriers of these bacteria.
  
  
  METHODS
  We screened for the presence of aerobic and anaerobic ESBL-producing bacteria and bla CTX-M in supragingival plaque samples from healthy human adults with culture-verified fecal carriage of CTX-M-producing Escherichia coli. The presence or absence of Enterobacteriaceae and ESBL-producing bacteria in plaque samples was evaluated using culture-based methods and consensus CTX-M PCR.
  
  
  RESULTS
  Oral samples were obtained from 17 participants with known previous carriage of ESBL-producing E. coli. No ESBL-producing bacteria or ESBL genes were detected using culture-based and molecular methods. One colony of Rahnella aquatilis harboring the class A ESBL gene bla RAHN-1/2 was identified in an oral sample from one of the participants.
  
  
  CONCLUSIONS
  This pilot study supports the notion that the presence of CTX-M-producing bacteria is uncommon in oral plaque of healthy human adult fecal carriers. Due to the limited number of persons tested, a low prevalence of oral ESBL-carriage in healthy adults or carriage in selected groups of patients cannot be excluded. To our knowledge, this is the first description of an R. aquatilis with the RAHN-1/2 gene in the oral cavity.
authors.affiliation: Department of Medical Microbiology, Vestre Viken Hospital Trust, Bærum, Norway.
authors.forename: Arne
authors.initials: A
authors.lastname: Søraas
authors.affiliation: Department of Oral Biology, University of Oslo, Oslo, Norway.
authors.forename: Ingar
authors.initials: I
authors.lastname: Olsen
authors.affiliation: Department of Microbiology and Infection Control, Reference Centre for Detection of Antimicrobial Resistance, University Hospital of North Norway, Tromsø, Norway ; Department of Medical Biology, Research Group for Host-Microbe Interactions, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.
authors.forename: Arnfinn
authors.initials: A
authors.lastname: Sundsfjord
authors.affiliation: Department of Oral Biology, University of Oslo, Oslo, Norway.
authors.forename: Trude
authors.initials: T
authors.lastname: Handal
authors.affiliation: Department of Medical Microbiology, Vestre Viken Hospital Trust, Bærum, Norway.
authors.forename: Ola
authors.initials: O
authors.lastname: Bjørang
authors.affiliation: Department of Medical Microbiology, Vestre Viken Hospital Trust, Bærum, Norway ; Department of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Pål Arne
authors.initials: PA
authors.lastname: Jenum
keywords: CTX-M; Enterobacteriaceae; extended-spectrum β-lactamase; oral carriage