title: Susceptibility of bacteria isolated from acute gastrointestinal infections to rifaximin and other antimicrobial agents in Mexico.
abstract: BACKGROUND
  Bacterial resistance may hamper the antimicrobial management of acute gastroenteritis. Bacterial susceptibility to rifaximin, an antibiotic that achieves high fecal concentrations (up to 8,000μg/g), has not been evaluated in Mexico.
  
  
  OBJECTIVE
  To determine the susceptibility to rifaximin and other antimicrobial agents of enteropathogenic bacteria isolated from patients with acute gastroenteritis in Mexico.
  
  
  METHODS
  Bacterial strains were analyzed in stool samples from 1,000 patients with diagnosis of acute gastroenteritis. The susceptibility to rifaximin (RIF) was tested by microdilution (<100, <200, <400 and <800μg/ml) and susceptibility to chloramphenicol (CHL), trimethoprim-sulfamethoxazole (T-S), neomycin (NEO), furazolidone (FUR), fosfomycin (FOS), ampicillin (AMP) and ciprofloxacin (CIP) was tested by agar diffusion at the concentrations recommended by the Clinical & Laboratory Standards Institute and the American Society for Microbiology.
  
  
  RESULTS
  Isolated bacteria were: enteropathogenic Escherichia coli (E. coli) (EPEC) 531, Shigella 120, non-Typhi Salmonella 117, Aeromonas spp. 80, enterotoxigenic E. coli (ETEC) 54, Yersinia enterocolitica 20, Campylobacter jejuni 20, Vibrio spp. 20, Plesiomonas shigelloides 20, and enterohemorrhagic E. coli (EHEC 0:157) 18. The overall cumulative susceptibility to RIF at <100, <200, <400, and <800μg/ml was 70.6, 90.8, 99.3, and 100%, respectively. The overall susceptibility to each antibiotic was: AMP 32.2%, T-S 53.6%, NEO 54.1%, FUR 64.7%, CIP 67.3%, CLO 73%, and FOS 81.3%. The susceptibility to RIF <400 and RIF <800μg/ml was significantly greater than with the other antibiotics (p<0.001).
  
  
  CONCLUSIONS
  Resistance of enteropathogenic bacteria to various antibiotics used in gastrointestinal infections is high. Rifaximin was active against 99-100% of these enteropathogens at reachable concentrations in the intestine with the recommended dose.
authors.affiliation: División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, México, D.F., México.
authors.forename: O
authors.initials: O
authors.lastname: Novoa-Farías
authors.affiliation: Departamento de Medicina Interna, Hospital Médica Sur, México, D.F., México. Electronic address: AFrati@alfawassermann.com.
authors.forename: A C
authors.initials: AC
authors.lastname: Frati-Munari
authors.affiliation: Alliance for the prudent use of antibiotics (APUA), Chapter Mexico. México, D.F. México.
authors.forename: M A
authors.initials: MA
authors.lastname: Peredo
authors.affiliation: División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, México, D.F., México.
authors.forename: S
authors.initials: S
authors.lastname: Flores-Juárez
authors.affiliation: División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, México, D.F., México.
authors.forename: O
authors.initials: O
authors.lastname: Novoa-García
authors.affiliation: División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, México, D.F., México.
authors.forename: J
authors.initials: J
authors.lastname: Galicia-Tapia
authors.affiliation: División de Microbiología Clínica, Unidad de Diagnóstico Microbiológico UDMSC, México, D.F., México.
authors.forename: C E
authors.initials: CE
authors.lastname: Romero-Carpio
mesh_terms: D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001424:Bacterial Infections / Q000382:microbiology*; D005759:Gastroenteritis / Q000382:microbiology*; D006801:Humans; D008800:Mexico; D008826:Microbial Sensitivity Tests; D012294:Rifamycins / Q000494:pharmacology*; D000078262:Rifaximin
chemical_list: D000900:Anti-Bacterial Agents; D012294:Rifamycins; D000078262:Rifaximin
keywords: Antibiotics; Antibióticos; Bacterial resistance; Bacterial susceptibility; Gastroenteritis; Resistencia bacteriana; Rifaximin; Rifaximina; Small intestinal bacterial overgrowth; Sobrepoblación bacteriana intestinal; Susceptibilidad bacteriana