Punpanich Warunee, Tantichattanon Worraporn, Wongwatcharapaiboon Siriporn, Treeratweeraphong Vipa
Division of Infectious Disease, Department of Pediatrics, Queen Sirikit National Institute of Child Health, College of Medicine, Rangsit University, Bangkok, Thailand.
J Med Assoc Thai. 2008 Oct;91 Suppl 3:S21-7.
To determine the in vitro activity of various antimicrobial agents including ertapenem, imipenem, meropenem, fosfomycin, netilmicin, colistin, and piperacillin/tazobactam against clinical isolates of cephalosporin-resistant gram-negative bacteria.
All clinical isolates of gram-negative bacteria obtained from patients receiving care at Queen Sirikit National Institute of Child Health (QSNICH), Bangkok, Thailand, from 2006-2007 were evaluated for antimicrobial susceptibility. Those resistant to all cephalosporins were further assessed for additional disc susceptibility and MIC test using E-tests.
Each of the fifty-five strains of extended spectrum beta-lactamase (ESBL) producing K. pneumoniae and E. coli were tested. The results showed excellent in vitro activity of the studied drugs against ESBL-producing K. pneumoniae with percent susceptibility of 100, 100, 100, 89.8, and 92.7 for ertapenem, imipenem, meropenem, fosfomycin, and colistin, respectively. MIC90 of ertapenem, imipenem, meropenem, fosfomycin, and colistin against K. pneumoniae were 0.23, 0.09, 0.38, 59.2, and 0.75 microg/ml, respectively. Piperacillin/tazobactam inhibited 68.2% of the tested isolates of K. pneumoniae. All studied drugs, except netilmicin, exhibited good activity against ESBL-producing Escherichia coli with 100% sensitivity for carbapenem, fosfomycin, colistin and 95.8% for piperacillin/tazobactam. MIC90 of ertapenem, imipenem, meropenem, fosfomycin, and colistin against Escherichia coli were 0.177, 0.25, 0.064, 2.85, and 0.58 microg/ml, respectively. Six strains of cephalosporin-resistant P. aeruginosa were isolated and tested for MIC. The results showed percent susceptibility of 66.7 and 33.3 for piperacillin/tazobactam and colistin, respectively. MIC90 of piperacillin/tazobactam and colistin against P. aeruginosa were 256 and 8 microg/ml, respectively. Twenty-four strains of cephalosporin-resistant Acinetobacter spp. were isolated with percent susceptibility of 17.6 and 95.5 for piperacillin/tazobactam and colistin, respectively. MIC90 of piperacillin/tazobactam and colistin against Acinetobacter spp. were 256 and 1.4 microg/ml, respectively.
Carbapenems, fosfomycin, and colistin exhibited excellent in vitro activity against both ESBL-producing K. pneumoniae and E. coli. Piperacillin/tazobactam exhibited good in vitro susceptibility against ESBL- producing E. coli, but not K. pneumoniae. Colistin was the most potent in vitro activity of antibiotics against cephalosporins-resistant Acinetobacter spp. However, cephalosporin-resistant Pseudomonas aeruginosa remained problematic, we recommend performing in vitro susceptibility test to determine appropriate antibiotic uses. E-test methods have been shown to be more accurate than disc diffusion test for evaluating colistin susceptibility.
确定包括厄他培南、亚胺培南、美罗培南、磷霉素、奈替米星、黏菌素和哌拉西林/他唑巴坦在内的多种抗菌药物对耐头孢菌素革兰氏阴性菌临床分离株的体外活性。
对2006年至2007年在泰国曼谷诗丽吉王后国家儿童健康研究所（QSNICH）接受治疗的患者所获得的所有革兰氏阴性菌临床分离株进行抗菌药敏评估。对所有头孢菌素耐药的菌株进一步通过额外的纸片药敏试验和使用E试验进行MIC测试。
对55株产超广谱β-内酰胺酶（ESBL）的肺炎克雷伯菌和大肠杆菌进行了测试。结果显示，所研究的药物对产ESBL的肺炎克雷伯菌具有出色的体外活性，厄他培南、亚胺培南、美罗培南、磷霉素和黏菌素的药敏率分别为100%、100%、100%、89.8%和92.7%。厄他培南、亚胺培南、美罗培南、磷霉素和黏菌素对肺炎克雷伯菌的MIC90分别为0.23、0.09、0.38、59.2和0.75微克/毫升。哌拉西林/他唑巴坦抑制了68.2%的受试肺炎克雷伯菌分离株。除奈替米星外，所有研究药物对产ESBL大肠杆菌均表现出良好活性，碳青霉烯类、磷霉素、黏菌素的敏感性为100%，哌拉西林/他唑巴坦为95.8%。厄他培南、亚胺培南、美罗培南、磷霉素和黏菌素对大肠杆菌的MIC90分别为0.177、0.25、0.064、2.85和0.58微克/毫升。分离出6株耐头孢菌素铜绿假单胞菌并进行MIC测试。结果显示，哌拉西林/他唑巴坦和黏菌素对其药敏率分别为66.7%和33.3%。哌拉西林/他唑巴坦和黏菌素对铜绿假单胞菌的MIC90分别为256和8微克/毫升。分离出24株耐头孢菌素不动杆菌属菌株；哌拉西林/他唑巴坦和黏菌素对其药敏率分别为17.6%和95.5%。哌拉西林/他唑巴坦和黏菌素对不动杆菌属的MIC90分别为256和1.4微克/毫升。
碳青霉烯类、磷霉素和黏菌素对产ESBL的肺炎克雷伯菌和大肠杆菌均表现出出色的体外活性；哌拉西林/他唑巴坦对产ESBL大肠杆菌表现出良好的体外敏感性，但对肺炎克雷伯菌无效。黏菌素是对抗耐头孢菌素不动杆菌属体外活性最强的抗生素。然而，耐头孢菌素铜绿假单胞菌仍然是个问题，我们建议进行体外药敏试验以确定合适的抗生素使用。已证明E试验方法在评估黏菌素敏感性方面比纸片扩散试验更准确。
