In vitro activity of clinically implemented β-lactams against Aerococcus urinae: presence of non-susceptible isolates in Switzerland.
We analyzed the in vitro susceptibility to several ?-lactams and vancomycin of 80 Aerococcus urinae isolates collected during 2011-2012 in Switzerland. MICs were determined by Etest (bioMérieux) on Müller-Hinton agar with 5% sheep blood and interpreted according to the CLSI and EUCAST criteria set for viridans streptococci. MIC50/90 for penicillin, amoxicillin, ceftriaxone and vancomycin were 0.016/0.064 mg/l, 0.032/0.064 mg/l, 0.125/0.5 mg/l and 0.38/0.5 mg/l, respectively. Three (3.8%) isolates were resistant to ceftriaxone regardless of the criteria used (MICs ?2 mg/l); one of them was also non-susceptible to penicillin (MIC of 0.25 mg/l) according to CLSI. β-lactam resistance in A. urinae is a concern and suggests that more studies are needed to determine the molecular mechanisms of such resistance.
Institute for Infectious Diseases, Faculty of Medicine, University of Bern, Friedbühlstrasse 51, CH-3010 Bern, Switzerland.
Agnese
A
Lupo
Yuvia N
YN
Guilarte
Sara
S
Droz
Cèdric
C
Hirzel
Hansjakob
H
Furrer
Andrea
A
Endimiani
D056570:Aerococcus / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D013557:Switzerland; D047090:beta-Lactams / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D047090:beta-Lactams