False susceptibility to cefotetan reported by MicroScan for DHA-type AmpC beta-lactamase-producing Klebsiella pneumoniae.
This study evaluated the accuracy of cefotetan susceptibility determination using the MicroScan WalkAway system for AmpC-producing Klebsiella pneumoniae. In total, 57 K. pneumoniae isolates that showed a D-shape flattening in a double-disk synergy test were studied. Cefotetan MICs were determined by the agar dilution method. The bla(DHA) gene was detected in all 57 isolates, one of which co-harboured bla(CMY-1). According to the MicroScan system, 28 isolates were susceptible, 18 were intermediately-resistant, and 11 were resistant to cefotetan. Compared with the agar dilution method, very major, minor and major error rates were 28.1% (16/57), 47.4% (27/57) and 1.8% (1/57), respectively.
Lee
S Y
SY
Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Park
Y J
YJ
Oh
E J
EJ
Yoo
J K
JK
Park
J J
JJ
Park
K G
KG
Han
K
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015313:Cefotetan / Q000494:pharmacology*; D005189:False Positive Reactions; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000295:instrumentation* / Q000379:methods; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015313:Cefotetan; C048795:AmpC beta-lactamases; D001618:beta-Lactamases