Evaluation of four methods for detecting the beta-lactamase activity in Neisseria gonorrhoeae isolated in Cuba.
Four methods (chromogenic, acidimetric, inhibition, and iodometric) for demonstration of the beta-lactamase production by 70 isolates of Neisseria gonorrhoeae, were evaluated in Cuba. There was 100% correlation between all beta-lactamase methods and the standardized penicillin dilution susceptibility test for penicillinase-non-producing N. gonorrhoeae. For penicillinase-producing N. gonorrhoeae strains, there was a perfect correlation between the chromogenic method and penicillin susceptibility testing, but one and two strains failed to give a positive result for beta-lactamase with the inhibition/acidimetric and the iodometric methods, respectively. There was a high concordance between the chromogenic method, considered as gold standard and the rest of penicillinase tests evaluated: Kappa Index (KI) = 0.98 for inhibition/acidimetric methods and KI = 0.97 for the iodometric method. The four methods evaluated were accurate, reproducible, easily readable, economical, and ease to use for screening primary isolates of N. gonorrhoeae in Cuba. We recommended the use of the inhibition method, when testing the penicillinase activity in gonococcal isolates in provincial and municipal reference laboratories.
Llanes
Rafael
R
Departmento de Bacteriología, Instituto de Medicina Tropical Pedro Kourí, Apdo Postal 601, Marianao 13, Ciudad de La Habana, Cuba. llanesrafael2002@yahoo.com
González
Miriam
M
Martínez
Isabel
I
Sosa
Jorge
J
Guzmán
Daymi
D
Gutiérrez
Oderay
O
Llop
Alina
A
Sánchez
Lizet
L
D001431:Bacteriological Techniques / Q000379:methods*; D003462:Cuba; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D009344:Neisseria gonorrhoeae / Q000201:enzymology*; D012680:Sensitivity and Specificity; D001618:beta-Lactamases / Q000096:biosynthesis*
D001618:beta-Lactamases