title: Prevalence of and risk factors associated with faecal carriage of CTX-M β-lactamase-producing Enterobacteriaceae in rural Thai communities.
abstract: OBJECTIVE
  To determine the prevalence of CTX-M β-lactamase-producing Enterobacteriaceae and to study the risk factors associated with faecal carriage in asymptomatic rural Thai people.
  
  
  METHODS
  In all, 417 stool samples were obtained from rural Thai people and screened for extended-spectrum β-lactamases (ESBLs) using MacConkey agar supplemented with 2 mg/L cefotaxime. Results were confirmed using cefotaxime and ceftazidime with and without clavulanic acid. The bla(CTX-M) genes were identified and genotyped using PCR with bacterial DNA samples. Multivariate analysis was performed to investigate risk factors associated with the faecal carriage of CTX-M producers.
  
  
  RESULTS
  The prevalence of CTX-M-type ESBL-producing Enterobacteriaceae was 65.7%. The CTX-M-9 group (60.6%) was dominant, followed by the CTX-M-1 group (38.7%). Most of the bacteria were Escherichia coli (85.4%) and Klebsiella pneumoniae (4.7%). Of a total of 234 E. coli strains, 48.7% belonged to phylogenetic group A, 28.6% to group B1, 15.8% to group D and 6.8% to group B2. Most CTX-M producers were susceptible to carbapenems and amikacin, but resistant to tetracycline and gentamicin. In a multivariate logistic regression model, better education status (OR 2.245; 95% CI 1.297-3.884), history of hospitalization (OR 1.643; 95% CI 1.036-2.603) and the use of antibiotics within the last 3 months (OR 1.883; 95% CI 1.221-2.903) were independently associated with faecal carriage.
  
  
  CONCLUSIONS
  Faecal carriage of CTX-M-type ESBL-producing Enterobacteriaceae among asymptomatic individuals in rural Thailand remains alarmingly high, and previous antibiotic use and a history of hospitalization may contribute to its dissemination.
authors.affiliation: Department of Bioinformatics,  Osaka University Graduate School of Medicine, Osaka,  Japan.
authors.forename: Ulzii-Orshikh
authors.initials: UO
authors.lastname: Luvsansharav
authors.forename: Itaru
authors.initials: I
authors.lastname: Hirai
authors.forename: Arisa
authors.initials: A
authors.lastname: Nakata
authors.forename: Kaori
authors.initials: K
authors.lastname: Imura
authors.forename: Kou
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Marie
authors.initials: M
authors.lastname: Niki
authors.forename: Chalit
authors.initials: C
authors.lastname: Komalamisra
authors.forename: Teera
authors.initials: T
authors.lastname: Kusolsuk
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002353:Carrier State / Q000453:epidemiology* / Q000382:microbiology; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence; D012307:Risk Factors; D012424:Rural Population; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D003470:Culture Media; D004269:DNA, Bacterial; D002442:Ceftazidime; D001618:beta-Lactamases; D002439:Cefotaxime