鲍曼不动杆菌耐药性和金属β内酰胺酶的检测

Determination of antimicrobial resistance and metallo-β-lactamases of 101 Acinetobacter baumannii clinical isolates

目的了解本院鲍曼不动杆菌对抗菌药物的耐药性以及对碳青霉烯类抗生素和头孢他啶耐药菌株是否产金属β内酰胺酶。方法对2002年4月—2003年1月本院临床分离的101株鲍曼不动杆菌采用NCCLS推荐的琼脂双倍稀释法测定了对15种抗菌药物的最低抑菌浓度(MICs),将对亚胺培南耐药或对头孢他啶高度耐药的菌株用金属螯合剂-抗生素稀释法检测是否产金属β内酰胺酶。结果101株鲍曼不动杆菌最常分离自痰,分布于全院16个临床科室,但有1/3以上来自于ICU病房。这101株对抗菌药物的耐药性突出,仅对亚胺培南、美罗培南和头孢吡肟保持较高的敏感率,分别为90·1%、88·1%和81·2%;而对包括头孢他啶的其他11种抗菌药物的敏感率均低于50%;而且多重耐药菌株常见。共有19株鲍曼不动杆菌对亚胺培南耐药和(或)对头孢他啶高度耐药。金属螯合剂-抗生素稀释法检测出9株产金属β内酰胺酶。结论本院鲍曼不动杆菌分离率高、分布广,对抗菌药物耐药严重;仅碳青霉烯和四代头孢菌素保持较高的敏感性;存在对亚胺培南耐药和(或)对头孢他啶高度耐药的鲍曼不动杆菌,其中部分耐药株产金属β内酰胺酶。

Objective To investigate antimicrobial resistance of Acinetobacter baumannii and detect metallo-β-lactamases （MBLs） in imipenem- and/or ceftazidime-resistant isolates. Methods 101 A. baumannii clinical isolates were isolated from April 2002 to January 2003 in West China Hospital, Sichuan University. Susceptibility test of these isolates was done by agar dilution followed NCCLS guidelines. Meanwhile, for imipenem-resistant and/or ceftazidime-highly-resistant （MIC 〉 128μg/ml） isolates, MBLs were tested by agar dilution method used imipenem and imipenem plus EDTA-1, lO-phenanthroline and/or ceftazidime and ceftazidime plus EDTA-1, lO-phenanthroline with positive controls. Results 90. 1%, 88. 1%, and 81.2% isolates were susceptible to imipenem, meropenem, and cefepime; However, less than 50% were susceptible to other 11 drugs including ceftazidime, aminoglycosides and ciprofloxacin. Multidrug resistant isolates were common. Nine MBLs-producing isolates were detected. Conclusion A. baumannii distributes widely in that hospital. Antimicrobial resistance of A. baumannii clinical isolates was severe. Only carbapenems and cefepime remain good activity against such isolates. MBLs existed in A. baumannii in western China.