Antimicrobial susceptibility of Listeria monocytogenes isolated from food and clinical cases in Navarra, Spain.
The susceptibility of 440 Listeria monocytogenes strains isolated from food (n=401) and clinical cases (n=39) between 1995 and 2005 was determined by standard agar dilution and E-test methods. Antimicrobial drugs currently used in veterinary and human therapy were tested, and they included penicillin G, ampicillin, cephalothin, gentamicin, chloramphenicol, tetracycline, doxycycline, trimethoprim, erythromycin, and clindamycin. The sensitivity of strains was established using Clinical and Laboratory Standards Institute (formerly NCCLS) breakpoints and MIC50 (the MIC for 50% of the strains) to MIC90 values. In general, isolates were susceptible to the majority of the antimicrobials tested, including beta-lactamics and aminoglycosides, which are normally used in the treatment of listeriosis. Resistance to tetracycline and doxycycline was found in five strains isolated from fresh trout belonging to the same fish farm. Molecular analysis by restriction endonuclease analysis showed a similar profile, suggesting the persistence of a strain well adapted to the presence of tetracycline in the environment of a fish farm, which is frequently used in aquaculture in order to prevent infections of fish.
Vitas
Ana Isabel
AI
Department of Microbiology and Parasitology, University of Navarra, C/Irunlarrea no 1, 31008 Pamplona, Spain. avitas@unav.es
Sánchez
Rosa María
RM
Aguado
Virginia
V
García-Jalón
Isabel
I
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017756:Aquaculture; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000187:drug effects*; D008088:Listeriosis / Q000188:drug therapy* / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D017747:Seafood / Q000382:microbiology*; D013030:Spain
D000900:Anti-Bacterial Agents