El-Karsh T, Tawfik A F, Al-Shammary F, Al-Salah S, Kambal A M, Shibl A M
College of Allied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
J Chemother. 1995 Dec;7(6):509-14. doi: 10.1179/joc.1995.7.6.509.
The activity of ciprofloxacin, imipenem and 12 other commonly used antibiotics was evaluated against 106 documented clinical isolates from a medical Intensive Care Unit (ICU). The resistance rates to ceftriaxone, cefotaxime, aztreonam and ceftazidime were 42, 25, 24 and 21%, respectively. Apart from Pseudomonas aeruginosa, all isolates were sensitive to ciprofloxacin and imipenem. Complete cross resistance among tested beta-lactam groups was uniformly evident in Enterobacter cloacae, Citrobacter freundii and P. aeruginosa. On the other hand, penicillins and second generation cephalosporins showed cross resistance among Escherichia coli and Klebseilla pneumoniae isolates. Induction experiments indicate that 70 and 62% of P. aeruginosa and E. cloacae or C. freundii produce class I cephalosporinase, respectively. Among all tested isolates, plasmid mediated extended spectrum beta-lactamase (ESBL) was detected in one isolate of K. pneumoniae. The plasmid mediated beta-lactamase is transferable and inhibited by beta-lactamase inhibitors. The transconjugates not only expressed resistance to extended spectrum beta-lactams and aztreonam but also toward tested aminoglycoside antibiotics, with the exception of gentamicin. The obtained transconjugates conferred high level resistance to ceftazidime and aztreonam but considerably low resistance to ceftriaxone and cefotaxime. The isoelectric point for the extended-spectrum beta-lactamase is 8.2.
对环丙沙星、亚胺培南及其他12种常用抗生素针对来自一所医疗重症监护病房（ICU）的106株有记录的临床分离株的活性进行了评估。对头孢曲松、头孢噻肟、氨曲南和头孢他啶的耐药率分别为42%、25%、24%和21%。除铜绿假单胞菌外，所有分离株对环丙沙星和亚胺培南敏感。在阴沟肠杆菌、弗氏柠檬酸杆菌和铜绿假单胞菌中，受试β-内酰胺类药物组之间完全交叉耐药普遍明显。另一方面，青霉素和第二代头孢菌素在大肠埃希菌和肺炎克雷伯菌分离株中显示出交叉耐药。诱导试验表明，分别有70%的铜绿假单胞菌以及62%的阴沟肠杆菌或弗氏柠檬酸杆菌产生I类头孢菌素酶。在所有受试分离株中，在一株肺炎克雷伯菌中检测到质粒介导的超广谱β-内酰胺酶（ESBL）。该质粒介导的β-内酰胺酶可转移且被β-内酰胺酶抑制剂抑制。接合子不仅对超广谱β-内酰胺类药物和氨曲南耐药，而且对受试氨基糖苷类抗生素耐药，但对庆大霉素除外。获得的接合子对头孢他啶和氨曲南具有高水平耐药，但对头孢曲松和头孢噻肟耐药性相当低。超广谱β-内酰胺酶的等电点为8.2。
