[Sensitivity of bovine and equine streptococci to beta-lactam antibiotics (benzylpenicillin, ampicillin, oxacillin, cefotaxime) in the agar diffusion and E-test].
368 streptococcal strains from udder secretions of cattle (Sc. agalactiae, Sc. dysgalactiae, Sc. uberis) and 191 streptococcal isolates from horse specimens (Sc. equi ssp. zooepidemicus, Sc. equi ssp. equi) originating from different agricultural regions in Germany (Lower Saxony, in particular the region of Weser-Ems, Bavaria, Altmark) were investigated for their sensitivity to 4 beta-lactam antibiotics (benzylpenicillin, ampicillin, oxacillin, cefotaxime). Two different test methods were applied: the agar diffusion test for determination of the diameter of the zone of inhibition and the E-test for determination of the minimal inhibitory concentration (MIC). According to the evaluation code of DIN 58,940, 98% to 100% of the isolates from the cow udder as well as of the Streptococcus strains from horses were sensitive to the four antibiotics tested. Only Sc. uberis was less sensitive to benzylpenicillin (79.7%) and Oxacillin (83.2%). The strains from different agricultural regions did not differ from each other concerning their sensitivity to beta-lactams. The results of the two methods of sensitivity testing were in satisfactory agreement: Compared to the MIC reference values, misclassifications occurred in the agar diffusion test only at an error rate of between 1.62% (for ampicillin) and 5.21% (for benzylpenicillin).
Bundesinstitut für gesundheitlichen Verbraucherschutz und Veterinärmedizin, Oldenburg.
H
H
Trolldenier
D
D
Klarmann
P
P
Krabisch
J
J
Rohde
A
A
Steiner
J
J
Verspohl
D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002417:Cattle; D002439:Cefotaxime / Q000494:pharmacology; D005260:Female; D005858:Germany; D006736:Horses; D008321:Mammary Glands, Animal / Q000378:metabolism / Q000382:microbiology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D010068:Oxacillin / Q000494:pharmacology; D010400:Penicillin G / Q000494:pharmacology; D013291:Streptococcus / Q000187:drug effects* / Q000302:isolation & purification
D000900:Anti-Bacterial Agents; D000667:Ampicillin; D002439:Cefotaxime; D010400:Penicillin G; D010068:Oxacillin