title: Antimicrobial susceptibilities of Lactobacillus, Pediococcus and Lactococcus human isolates and cultures intended for probiotic or nutritional use.
abstract: OBJECTIVE
  To determine MICs of 16 antimicrobials representing all major classes for 473 taxonomically well-characterized isolates of lactic acid bacteria (LAB) encompassing the genera Lactobacillus, Pediococcus and Lactococcus. To propose tentative epidemiological cut-off (ECOFF) values for recognizing intrinsic and acquired antimicrobial resistances in numerically dominant species.
  
  
  METHODS
  On the basis of depositors' information, LAB were grouped in categories of probiotic, nutritional, probiotic or nutritional research, human and animal isolates and tested for their antibiotic susceptibilities by broth microdilution using LAB susceptibility test medium (LSM). Tentative ECOFFs were defined according to the recommendations of the European Committee on Antimicrobial Susceptibility Testing. Isolates showing acquired antimicrobial resistance(s) were selected for PCR-based detection of resistance gene(s) and in vitro conjugative transfer experiments.
  
  
  RESULTS
  Tentative ECOFF values of 13 antibiotics were determined for up to 12 LAB species. Generally, LAB were susceptible to penicillin, ampicillin, ampicillin/sulbactam, quinupristin/dalfopristin, chloramphenicol and linezolid. LAB exhibited broad or partly species-dependent MIC profiles of trimethoprim, trimethoprim/sulfamethoxazole, vancomycin, teicoplanin and fusidic acid. Three probiotic Lactobacillus strains were highly resistant to streptomycin. Although erythromycin, clindamycin and oxytetracycline possessed high antimicrobial activities, 17 Lactobacillus isolates were resistant to one or more of these antibiotics. Eight of them, including six probiotic and nutritional cultures, possessed erm(B) and/or tet(W), tet(M) or unidentified members of the tet(M) group. In vitro intra- and interspecies filter-mating experiments failed to show transfer of resistance determinants.
  
  
  CONCLUSIONS
  Finding of acquired resistance genes in isolates intended for probiotic or nutritional use highlights the importance of antimicrobial susceptibility testing in documenting the safety of commercial LAB.
authors: Robert Koch Institute, Wernigerode Branch, Wernigerode, Germany. i.klare@rki.de
authors: Ingo
authors: I
authors: Klare
authors: Carola
authors: C
authors: Konstabel
authors: Guido
authors: G
authors: Werner
authors: Geert
authors: G
authors: Huys
authors: Vanessa
authors: V
authors: Vankerckhoven
authors: Gunnar
authors: G
authors: Kahlmeter
authors: Bianca
authors: B
authors: Hildebrandt
authors: Sibylle
authors: S
authors: Müller-Bertling
authors: Wolfgang
authors: W
authors: Witte
authors: Herman
authors: H
authors: Goossens
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D007778:Lactobacillus / Q000187:drug effects*; D017045:Lactococcus / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D010376:Pediococcus / Q000187:drug effects*; D019936:Probiotics / Q000592:standards*
chemical_list: D000900:Anti-Bacterial Agents