[Behavior of ceftazidime in regard to different classes of beta-lactamases. The situation in 1988].
Following Ambler's observations, B-lactamases can be divided in four classes, probably derived from a very small number of ancestral genes. Class A includes the TEM-type beta-lactamases (TEM-1, TEM-2), PIT-2/SHV-1 and others which do not hydrolyse ceftazidime and other third-generation cephalosporins. The new plasmid-mediated beta-lactamases markedly active against third-generation cephalosporins also belong to class A and the primary structures of few of them are known. All the class A beta-lactamases are highly susceptible to the action of beta-lactamase inhibitors: clavulanic acid, sulbactam, YTR-830, and are devoid of any hydrolytic properties for cephamycins and imipenem. Third-generation cephalosporins are slowly hydrolyzed by the class C beta-lactamases: the inducible cephalosporinases. Thus only organisms which produce derepressed cephalosporinases are resistant to third-generation cephalosporins, but individual variations are known.
Labia
R
R
Muséum National d'Histoire Naturelle, UA 401 CNRS, Paris.
Barthélémy
M
M
Peduzzi
J
J
Morand
A
A
Tiwari
K
K
D002442:Ceftazidime / Q000378:metabolism*; D004352:Drug Resistance, Microbial; D010957:Plasmids; D013329:Structure-Activity Relationship; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
D002442:Ceftazidime; D001618:beta-Lactamases
Comportement de la ceftazidime à l'égard de diverses classes de bêtalactamases. Situation en 1988.