鲍曼不动杆菌的产酶现状及抗菌药物体外联合抗菌活性研究

Analysis of zymogenic state and in vitro antimicrobial agent combination activity against Acinetobacter baumannii

目的了解鲍曼不动杆菌产酶现状与耐药性以及抗菌药物体外联合对其的抗菌活性,为临床治疗鲍曼不动杆菌感染合理用药提供实验依据。方法常规培养分离细菌,并以VITEK-2全自动微生物鉴定仪鉴定;药敏试验采用K-B纸片法,最低抑菌浓度(MIC)测定采用琼脂平板倍比稀释法,按美国临床实验室标准化研究所标准进行。结果96株鲍曼不动杆菌中产金属β-内酰胺酶(MBLs)菌株占94.79%(91株);产AmpC酶菌株占36.46%(35株),产质粒型AmpC酶菌株占35.42%(34株),产诱导型AmpC酶菌株占26.04%(25株)。多粘菌素B对产MBLs、AmpC酶鲍曼不动杆菌的抑菌率分别为85.71%、88.57%;哌拉西林/他唑巴坦联合阿米卡星对产MBLs及产AmpC酶鲍曼不动杆菌的协同作用分别为51.65%与41.67%。结论鲍曼不动杆菌产酶率高,多种酶并存,耐药机制复杂。临床对产酶鲍曼不动杆菌感染的治疗,应谨慎选择碳青霉烯类药物,建议选用含酶抑制剂复合药物(如哌拉西林/他唑巴坦或头孢哌酮/舒巴坦)联合阿米卡星或多粘菌素B治疗。

Objective To realize the zymogenic state and drug resistance of Acinetobacter baurnannii （A. baumannil） and antimicrobial combination activity in vitro test in order to provide laboratory data for clinical treatment. Methods All strains were isolated and identified by routine procedure and VITEK-2 automatic bacterial identification system, routine antimicrobial susceptibility tests were performed with Kirby-Bauer method and MICs were detected with agar dilution method according to CLSI. Results Ninety-one of 96 （94. 79%） A. baumannii strains produced metallo-β-1actmases, 36. 46% （35 strains） produced AmpC, 35. 42% （34 strains） and 26. 04% （25 strains） produced plasmid AmpC and inducible AmpC, respectively. The inhibition rate of polymyxin B to metallo- β-lactmases-producing and AmpC-producing A. baurnannii was 85.71% and 88. 57%, respectively. The synergy of piperacillin/tazobactam plus amikacin to metallo-β-lactmases-producing and AmpC-producing A. baurnannii was 51.65 % and 41. 67%, respectively. Conclusion The zymogenic fates and drug resistance of A. baurnannii are high, mostly due to multiplex drug-resistance mechanism. Clinical treatment should use carbapenems prudently against enzyme-producing A. baumannii, and should first select enzyme-inhibitory drugs （piperacillin/tazobactam or cefoperazone/sulbactam） combined with amikacin or polymyxin B for treatment.