Fung-Tomc J, Dougherty T J, DeOrio F J, Simich-Jacobson V, Kessler R E
Department of Microbiology, Bristol-Myers Company, Wallingford, Connecticut 06492.
Antimicrob Agents Chemother. 1989 Apr;33(4):498-502. doi: 10.1128/AAC.33.4.498.
One hundred clinical isolates resistant to ceftazidime and/or cefotaxime were examined for susceptibility to cefepime. The most frequently encountered ceftazidime-cefotaxime-resistant strains belonged to the genera Enterobacter, Pseudomonas, and Citrobacter. Among these strains, 92% were resistant to cefoperazone, 91% were resistant to cefotaxime, 84% were resistant to ceftazidime, and 6% were resistant to cefepime. Of the members of the family Enterobacteriaceae, 57% were resistant to ceftriaxone. The six strains resistant to cefepime were all Pseudomonas aeruginosa and were resistant to both cefotaxime and ceftazidime. Cefepime-resistant P. aeruginosa strains had exceptionally high levels of beta-lactamase activity, higher than the levels found in strains resistant to ceftazidime but susceptible to cefepime. The beta-lactamases from the cefepime-resistant strains were type I (Richmond-Sykes), were constitutively produced, and did not have increased affinity or hydrolytic activity for cefepime. Thus, cefepime was active against most gram-negative bacteria which have developed resistance to the broad-spectrum cephalosporins, and resistance to cefepime in P. aeruginosa appears to be associated with higher beta-lactamase levels than in cefepime-susceptible strains.
检测了100株对头孢他啶和/或头孢噻肟耐药的临床分离株对头孢吡肟的敏感性。最常见的对头孢他啶-头孢噻肟耐药的菌株属于肠杆菌属、假单胞菌属和柠檬酸杆菌属。在这些菌株中，92%对头孢哌酮耐药，91%对头孢噻肟耐药，84%对头孢他啶耐药，6%对头孢吡肟耐药。肠杆菌科成员中，57%对头孢曲松耐药。6株对头孢吡肟耐药的菌株均为铜绿假单胞菌，且对头孢噻肟和头孢他啶均耐药。对头孢吡肟耐药的铜绿假单胞菌菌株具有异常高水平的β-内酰胺酶活性，高于对头孢他啶耐药但对头孢吡肟敏感的菌株。来自对头孢吡肟耐药菌株的β-内酰胺酶为I型（里士满-赛克斯型），为组成型产生，对头孢吡肟没有增加的亲和力或水解活性。因此，头孢吡肟对大多数已对广谱头孢菌素产生耐药性的革兰氏阴性菌具有活性，铜绿假单胞菌对头孢吡肟的耐药性似乎与比头孢吡肟敏感菌株更高的β-内酰胺酶水平有关。
