Antimicrobial susceptibilities and occurrence of resistance genes in bovine Helcococcus ovis isolates

• Published in: Veterinary microbiology 2011-05, Vol.149 (3-4), p.488-491
• Main Authors: Bilk, Sabine, Nordhoff, Marcel, Schulze, Christoph, Wieler, Lothar H., Kutzer, Peter
• Format: Article
• Language: English
• Subjects: Abiotrophia; ampicillin; Animals; Anti-Bacterial Agents - pharmacology; antibiotic resistance; Antimicrobial susceptibility; bacterial infections; Biological and medical sciences; cattle; Cattle - microbiology; cattle diseases; cephalothin; Clindamycin - pharmacology; Drug Resistance, Bacterial - genetics; erm(B) gene; erythromycin; Erythromycin - pharmacology; Fundamental and applied biological sciences. Psychology; genes; genetic resistance; Gram-Positive Endospore-Forming Rods - drug effects; Gram-Positive Endospore-Forming Rods - genetics; Helcococcus ovis; Lincosamides - pharmacology; Macrolides - pharmacology; Microbial Sensitivity Tests; Microbiology; minimum inhibitory concentration; MLSB resistance; Ovis; Phenotype; Streptogramin Group B - pharmacology; tet(L) gene; tet(M) gene; tetracycline; Tetracycline - pharmacology; Tetracycline resistance; Tetracycline Resistance - genetics
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2010.11.012

The aim of the study was to investigate antimicrobial susceptibilities of bovine Helcococcus ovis isolates and to detect genes encoding for H. ovis erythromycin and tetracycline resistance. Twenty-nine isolates were included and the minimal inhibitory concentrations (MICs) of seven antimicrobials were determined using test conditions as given in an approved CLSI guideline for the pyridoxal-dependent Abiotrophia spp. and Granulicatella spp. Furthermore, the macrolide resistance phenotype was examined by the erythromycin–clindamycin double-disk test (D-zone test). Erythromycin MICs of ≥8μg/ml were found in three (10%) isolates which also presented the macrolide, lincosamide, and streptogramin B (MLSB) resistance phenotype, either constitutive or inducible. The erm(B) gene was detected in one of these isolates. Increased tetracycline MICs (≥8μg/ml) were obtained for 24 (83%) isolates, mostly associated with the tet(M) gene alone (n=21) or both the tet(L) and tet(M) genes (n=2). The MICs determined for penicillin, ampicillin, amoxicillin-clavulanic acid, and cephalothin did not indicate resistance to these antimicrobials. The study suggests that resistance to MLSB antimicrobials and tetracycline is frequent in H. ovis. Moreover, this is the first report about occurrence of the resistance genes erm(B), tet(L), and tet(M) in the Helcococcus genus.