title: Analysis of antimicrobial resistance and class 1 integrons among strains from upper respiratory tract of healthy adults.
abstract: OBJECTIVE
  The distribution and characterization of integrons among opportunistic pathogens from nasopharynx of healthy adults.
  
  
  METHODS
  A total of 1,019 nasopharyngeal samples from healthy adults were collected; bacteria were identified by API system; antibiotic susceptibility were tested by K-B method; class 1, 2 and 3 integrons were examined by degenerate primers of the genetic content of integrons were analyzed by PCR and DNA sequencing.
  
  
  RESULTS
  Out of the 1,019 cases, 743 (72.9%) opportunistic pathogens were isolated. The top five commons organism identified were Coagulase-negative staphylococcus (n=404), Staphylococcus aureus (n=109), Haemophilus influenzae (n=74), Streptococcus pneumoniae (n=49) and Klebsiella pneumoniae (n=32). Eight (25.0%) isolates of K. pneumoniae produced the ESBLs. The isolated rates of S. aureus and H. influenzae were decreased with aging. 6.3% (2/32) K. pneumoniae isolates and 16.7% (1/8) Proteus isolates carried class 1 integrons. Among intI1-positive strains, sequencing analysis revealed that one of the integron positive K. pneumoniae isolates harbored gene cassette aadA5-dfrA17. Proteus isolates harbored gene cassette aadA2-dhfrXII.
  
  
  CONCLUSIONS
  The results stressed the need for continued surveillance of bacteria from the asymptomatic carriers.
authors.affiliation: Department of Respiratory Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China; ; Department of Respiratory Medicine, People's Hospital of Fuyang City, Fuyang 236003, China;
authors.forename: Haiyan
authors.initials: H
authors.lastname: Liu
authors.forename: Hai
authors.initials: H
authors.lastname: Wang
authors.forename: Mao
authors.initials: M
authors.lastname: Huang
authors.forename: Yaning
authors.initials: Y
authors.lastname: Mei
authors.forename: Bing
authors.initials: B
authors.lastname: Gu
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.forename: Yiling
authors.initials: Y
authors.lastname: Huang
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Yanling
authors.initials: Y
authors.lastname: Xu
authors.forename: Tong
authors.initials: T
authors.lastname: Wang
keywords: Antimicrobial resistance; class 1 integron; gene cassettes; healthy adults; upper respiratory tract