title: Antibiotic susceptibility of Listeria monocytogenes in Argentina.
abstract: BACKGROUND
  Listeria monocytogenes is the causative agent of listeriosis, a food-borne disease that mainly affects pregnant women, the elderly, and immunocompromised patients. The primary treatment of choice of listeriosis is the combination of ampicillin or penicillin G, with an aminoglycoside, classically gentamicin. The second-choice therapy for patients allergic to β-lactams is the combination of trimethoprim with a sulfonamide (such as co-trimoxazole). The aim of this study was to analyze the antimicrobial susceptibility profile of strains isolated from human infections and food during the last two decades in Argentina.
  
  
  METHODS
  The minimal inhibitory concentration (MIC) of 8 antimicrobial agents was determined for a set of 250 strains of L. monocytogenes isolated in Argentina during the period 1992-2012. Food-borne and human isolates were included in this study. The antibiotics tested were ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, erythromycin, gentamicin, penicillin G, tetracycline and rifampicin. Breakpoints for penicillin G, ampicillin and trimethoprim-sulfamethoxazole were those given in the CLSI for L. monocytogenes. CLSI criteria for staphylococci were applied to the other antimicrobial agents tested. Strains were serotyped by PCR, and confirmed by an agglutination method.
  
  
  RESULTS
  Strains recovered from human listeriosis patients showed a prevalence of serotype 4b (71%), with the remaining 29% corresponding to serotype 1/2b. Serotypes among food isolates were distributed as 62% serotype 1/2b and 38% serotype 4b. All antimicrobial agents showed good activity.
  
  
  CONCLUSIONS
  The strains of L. monocytogenes isolated in Argentina over a period of 20 years remain susceptible to antimicrobial agents, and that susceptibility pattern has not changed during this period.
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: mprieto@anlis.gov.ar.
authors.forename: Mónica
authors.initials: M
authors.lastname: Prieto
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Claudia
authors.initials: C
authors.lastname: Martínez
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Lorena
authors.initials: L
authors.lastname: Aguerre
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: María Florencia
authors.initials: MF
authors.lastname: Rocca
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Lucía
authors.initials: L
authors.lastname: Cipolla
authors.affiliation: Servicio Bacteriología Especial, Departamento Bacteriología, Instituto Nacional de Enfermedades Infecciosas (INEI) - Administración Nacional de Laboratorios e Institutos de Salud (ANLIS) "Dr. Carlos G. Malbrán", Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Raquel
authors.initials: R
authors.lastname: Callejo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001118:Argentina; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects*; D008088:Listeriosis / Q000453:epidemiology / Q000382:microbiology; D008826:Microbial Sensitivity Tests
chemical_list: D000900:Anti-Bacterial Agents
keywords: Antibiotic susceptibility; CIM; Listeria monocytogenes; MIC; Susceptibilidad antibiótica