Oxacillinase-Mediated Resistance to Cefepime and Susceptibility to Ceftazidime in Pseudomonas aeruginosa

Pseudomonas aeruginosa clinical isolate SOF-1 was resistant to cefepime and susceptible to ceftazidime. This resistance phenotype was explained by the expression of OXA-31, which shared 98% amino acid identity with a class D β-lactamase, OXA-1. The oxa-31 gene was located on a ca. 300-kb nonconjugative plasmid and on a class 1 integron. No additional efflux mechanism for cefepime was detected in P. aeruginosa SOF-1. Resistance to cefepime and susceptibility to ceftazidime in P. aeruginosa were conferred by OXA-1 as well.

临床分离的铜绿假单胞菌（Pseudomonas aeruginosa）SOF-1株对头孢吡肟（cefepime）耐药，对头孢他啶（ceftazidime）敏感。该耐药表型由OXA-31的表达所介导，OXA-31与D类β-内酰胺酶（class D β-lactamase）OXA-1的氨基酸序列一致性达98%。oxa-31基因定位于约300kb的非接合性质粒（nonconjugative plasmid）以及1类整合子（class 1 integron）中。在铜绿假单胞菌SOF-1株中未检测到针对头孢吡肟的其他外排耐药机制。铜绿假单胞菌中头孢吡肟耐药与头孢他啶敏感的表型同样可由OXA-1介导。