鲍曼不动杆菌生物被膜对抗菌药物耐药性的影响

目的了解临床分离的鲍曼不动杆菌生物被膜形成能力及生物被膜形成后对耐药性的影响。方法收集临床分离的鲍曼不动杆菌47株,采用结晶紫染色法测定鲍曼不动杆菌生物被膜的形成能力,检测12种抗菌药物对形成生物被膜的菌株在浮游状态及生物被膜状态下的最低抑菌浓度(MIC);阳性菌株在不同培养条件(振荡与静止)、不同材料(玻璃试管和聚丙烯塑料离心管)中生物被膜形成能力。结果 13株(27.66%)临床菌株形成生物被膜。浮游状态下13株菌对检测抗菌药物的耐药率均35%,未出现对多粘菌素和替加环素耐药的菌株;生物被膜状态下替加环素耐药率为15.38%,其余抗菌药物的耐药率均为100%。13株试验菌株,在振荡条件下≥10株菌形成的生物被膜菌吸光度高于静止培养条件下形成的生物被膜菌,≥10株菌在聚丙烯离心管中形成生物被膜菌吸光度高于玻璃试管中形成的生物被膜菌。结论鲍曼不动杆菌形成生物被膜后对抗菌药物的耐药性发生巨大变化,可能导致抗菌药物治疗感染的失败。

Effect of Acinetobacter baumannii biofilm on antimicrobial resistance

ObjectiveTo understand biofilm forming ability of Acinetobacter baumannii(A. baumannii) in clinical isolates, and evaluate the effect of biofilm formation on antimicrobial resistance. MethodsA total of 47 A. baumannii clinical isolates were collected, biofilm forming ability was detected by crystal violet staining assay, the minimal inhibitory concentration(MIC) of 12 kinds of antimicrobial agents to biofilm forming isolates were detected when the isolates were in planktonic or biofilm formatted condition; biofilm forming ability of positive isolates at different culture condition (shaking or stable) and on different materials(glass tube or polypropylene plastic centrifugal tube) were detected. ResultsThirteen isolates (27.66%) exhibited biofilm formation. In planktonic condition, antimicrobial resistance rates of these isolates were all <35%, no isolates shown resistance to polymyxin and tigecycline, in biofilm formatted condition, resistance rates to tigecycline was 15.38%，resistance rates to the other antimicrobial agents were all 100%. Of 13 tested isolates, ≥10 isolates shown higher absorbance in the shaking condition than in the stable condition, ≥10 tested isolates shown higher absorbance in polypropylene plastic centrifugal tube than in the glass tube. ConclusionThe resistance of A. baumannii to antimicrobial agents is greatly changed after the formation of biofilm, which may results in the failure of antimicrobial therapy for infection.