Gargalianos P, Oppenheim B A, Skepastianos P, Livermore D M, Williams R J
Department of Medical Microbiology, London Hospital Medical College, UK.
J Antimicrob Chemother. 1988 Dec;22(6):841-8. doi: 10.1093/jac/22.6.841.
The activities of cefpirome, cefotaxime, ceftazidime and ceftriaxone were compared against laboratory and clinical strains of Pseudomonas aeruginosa. Isolates with well characterised resistance mechanisms were included. Against carbenicillin-susceptible isolates cefpirome was more active than cefotaxime and ceftriaxone, but less active than ceftazidime. The activity of all four cephalosporins was impaired against isolates that had increased intrinsic (i.e. non-beta-lactamase-mediated) carbenicillin resistance. However, cefpirome and ceftazidime, unlike the other compounds, remained active at less than 16 mg/l against such strains, whereas cefotaxime and ceftriaxone largely failed to do so. Cefpirome maintained full activity against most isolates with plasmid-mediated beta-lactamases, as did the other cephalosporins. Transconjugant studies indicated that only LCR-1 and PSE-2 enzymes could protect P. aeruginosa against cefpirome. Isolates with partial or total chromosomal beta-lactamase derepression were highly resistant to cefotaxime and ceftriaxone (MIC greater than 128 mg/l) but only those with total derepression were resistant (MIC 16-32 mg/l) to cefpirome and ceftazidime, while those with partial derepression were sensitive to 4-8 mg/l of the latter antibiotics. Comparison of cefpirome MICs for totally-derepressed P. aeruginosa and their enzyme-deficient mutants indicated that chromosomal beta-lactamase gave less protection against cefpirome than against other cephalosporins tested. Cefpirome was a weak inducer of class I beta-lactamases. Overall, therefore, cefpirome behaved similarly to ceftazidime against the different P. aeruginosa resistance types.
比较了头孢匹罗、头孢噻肟、头孢他啶和头孢曲松对铜绿假单胞菌实验室菌株和临床菌株的活性。研究纳入了具有明确耐药机制的分离株。对于对羧苄西林敏感的分离株，头孢匹罗比头孢噻肟和头孢曲松更具活性，但比头孢他啶活性低。对于固有（即非β-内酰胺酶介导）羧苄西林耐药性增加的分离株，这四种头孢菌素的活性均受损。然而，与其他化合物不同，头孢匹罗和头孢他啶对这类菌株在浓度低于16mg/L时仍保持活性，而头孢噻肟和头孢曲松在很大程度上无法做到这一点。头孢匹罗对大多数携带质粒介导的β-内酰胺酶的分离株保持完全活性，其他头孢菌素也是如此。接合子研究表明，只有LCR-1和PSE-2酶能保护铜绿假单胞菌免受头孢匹罗的影响。部分或完全染色体β-内酰胺酶去阻遏的分离株对头孢噻肟和头孢曲松高度耐药（MIC大于128mg/L），但只有完全去阻遏的分离株对头孢匹罗和头孢他啶耐药（MIC为16 - 32mg/L），而部分去阻遏的分离株对后两种抗生素敏感，其MIC为4 - 8mg/L。对完全去阻遏的铜绿假单胞菌及其酶缺陷突变体的头孢匹罗MIC进行比较表明，染色体β-内酰胺酶对头孢匹罗的保护作用比对其他测试的头孢菌素小。头孢匹罗是I类β-内酰胺酶的弱诱导剂。因此，总体而言，头孢匹罗在针对不同类型铜绿假单胞菌耐药性方面的表现与头孢他啶相似。
