Use of beta-lactamase inhibitors in disk tests to detect plasmid-mediated AmpC beta-lactamases.
Seeking a simple disk test for detection of organisms producing plasmid-mediated AmpC beta-lactamases, we evaluated the diagnostic utility of the beta-lactamase inhibitors 48-1220 (Ro 48-1220) and LN-2-128. Using NCCLS disk methodology, inhibition zone diameters were determined for five beta-lactam antibiotics tested alone and in combination with 20 microg of either 48-1220 or LN-2-128. Using an increase of > or =4 mm in zone diameter in the presence of an inhibitor as a positive test, cefotetan with LN-2-128 and 48-1220 was adequate for the detection of organisms producing plasmid-mediated AmpCs (specificity of 90% and sensitivity of 100%).
Black
Jennifer A
JA
Center for Research in Anti-Infectives and Biotechnology, Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, Nebraska, USA.
Thomson
Kenneth S
KS
Pitout
Johann D D
JD
D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D001431:Bacteriological Techniques / Q000706:statistics & numerical data; D004791:Enzyme Inhibitors; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D012680:Sensitivity and Specificity; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics*
D001426:Bacterial Proteins; D004791:Enzyme Inhibitors; D065093:beta-Lactamase Inhibitors; C048795:AmpC beta-lactamases; D001618:beta-Lactamases