头孢妥仑对社区获得性呼吸道感染流感嗜血菌及黏膜炎莫拉菌的体外抗菌活性

In vitro activity of cefditoren against Haemophilus influenzaeand Moraxella catarrhaliscausing community-acquired respiratory tract infections

目的评价头孢妥仑及其对照药物对社区获得性呼吸道感染流感嗜血菌和黏膜炎莫拉菌的体外抗菌活性。方法收集2009-2010年来自全国6个城市10所医院社区获得性呼吸道感染的266株流感嗜血菌及76株黏膜炎莫拉菌;使用微量肉汤稀释法测定头孢妥仑和对照药物的最低抑菌浓度(MICs);使用WHONET5.6软件分析各药物的敏感率、MIC50、MIC90等信息。结果流感嗜血菌除对氨苄西林、头孢呋辛、头孢克洛的敏感率为81.2%、88.7%、88.0%外,对其他抗菌药物均体现出高的敏感性,敏感率>97.0%;266株流感嗜血菌中,216株为氨苄西林敏感且非产β-内酰胺酶菌株,占81.2%,26株为氨苄西林耐药且产β-内酰胺酶菌株,占9.8%,24株为氨苄西林耐药但非产β-内酰胺酶菌株(BLNAR),占9.0%;无论菌株是否产β-内酰胺酶或氨苄西林耐药,头孢妥仑在测试药物中显示出极佳的抗菌活性,MIC50、MIC90分别为0.016、0.064μg/ml;在0.5μg/ml浓度时头孢妥仑抑制了所有BLNAR菌株;76株黏膜炎莫拉菌中有70株产β-内酰胺酶,非产β-内酰胺酶的菌株对所有抗菌药物敏感,对头孢妥仑MIC90为0.064μg/ml;产β-内酰胺酶菌株对头孢呋辛、头孢克洛、阿奇霉素的敏感率稍有降低,为98.6%、98.6%、94.3%,头孢妥仑MIC90为0.5μg/ml。结论头孢妥仑对社区呼吸道感染流感嗜血菌及黏膜炎莫拉菌体现出良好的体外抗菌活性,可作为社区呼吸道感染的治疗选择,其抗菌活性需密切监测。

OBJECTIVE To evaluate the in vitro activity of cefditoren against Haemophilus influenzae and Moraxella catarrhalis causing community-acquired respiratory tract infection（CARTI）.METHODS A total of 266 H.influenzae and 76 M.catarrhalis were isolated from 10 centers located at 6 cities in China from Jan 2009 to May 2010.Microdilution method was used to determine minimum inhibitory concentrations（MICs）.WHONET 5.6 software was used to calculate the susceptibility,MIC50,MIC90 and other indexes.RESULTS H.influenzae exhibited high susceptibility to all tested antimicrobial agents（97.0%） except ampicillin,cefuroxime and cefaclor（81.2%,88.7% and 88%,separately）.Among the 266 H.influenzae isolates,216（81.2%） were ampicillin-sensitve β-lactamase-nonproducing strains,26（9.8%） were ampicillin-resistant β-lactamase-producing strains and 24（9.0%） were ampicillin-resistant β-lactamase-nonproducing strains（BLNAR）.Cefditoren showed the excellent activity with the lowest MIC50 and MIC90（0.016/0.064 μg/ml） among all tested drugs against H.influenzae,which was independent of β-lactamase production or ampicillin resistance.Cefditoren at concentration of 0.5 μg/ml inhibited all BLNAR strains.Seventy out of 76 isolates of M.catarrhalis produced β-lactamase.β-lactamase-non-producing isolates were susceptible to all tested drugs and the MIC90 of cefditoren was 0.064 μg/ml.β-lactamase-producing isolates showed slight decrease of susceptibility rates to cefuroxime,cefaclor and azithromycin（98.6%,98.6% and 94.3%,separately）,while the MIC90 of cefditoren was 0.5 μg/ml.CONCLUSION Excellent intrinsic in vitro activity of cefditoren suggested that it could be a good choice for treatment of CARTI caused by H.influenzae and M.catarrhalis in China,while the activity should be closely monitored.