[Substrate specificity of the beta-lactamases found in a number of clinical strains of gram-negative bacteria].
The substrate profiles of beta-lactamases defected in 46 clinical polyresistant strains of gram-negative bacteria were determined. By the substrate profile and sensitivity to inhibitors (dicloxacillin and p-CMB) beta-lactamases were considered to belong to classes I, II, III, IV and V of the Richmond classification. The molecular weights of the enzymes were measured. Enterobacter aerogenes 6803, Enterobacter aerogenes 11030 and Klebsiella pneumoniae 970 produced simultaneously two beta-lactamases belonging to different classes. beta-Lactamases of classes I and III were detected in the cells of Enterobacter aerogenes 6803. The cells of Enterobacter aerogenes 11030 contained beta-lactamases of classes V and III and the cells of Klebsiella pneumonia 970 beta-lactamases of classes II and III. Therefore, in all the cases one of beta-lactamases belonged to the class III enzyme close to TEM beta-lactamases by its substrate profile, molecular weight and sensitivity to the inhibitors. Cephalexin and dicloxacillin were most frequently stable to the effect of the above beta-lactamases. The enzymes from 26 strains did not hydrolyse or hydrolysed slightly cephalexin and the enzymes from 19 strains did not hydrolyse of hydrolysed slightly dicloxacillin.
D000900:Anti-Bacterial Agents / Q000378:metabolism; D002850:Chromatography, Gel; D004352:Drug Resistance, Microbial; D006090:Gram-Negative Bacteria / Q000201:enzymology* / Q000302:isolation & purification; D006801:Humans; D008970:Molecular Weight; D013379:Substrate Specificity; D001618:beta-Lactamases / Q000145:classification / Q000378:metabolism*; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases
Izuchenie substratnoĭ spetsifichnosti beta-laktamaz, obnaruzhennykh u riada klinicheskikh shtammov gramotritsatel'nykh bakteriĭ.