分析耐碳青霉烯类鲍曼不动杆菌中的青霉素结合蛋白（PBPs）。

BACKGROUND & OBJECTIVES: Acinetobacter baumannii is a Gram-negative, cocco-bacillus aerobic pathogen responsible for nosocomial infections in hospitals. In the recent past A. baumannii had developed resistance against β-lactams, even against carbapenems. Penicillin-binding proteins (PBPs) are crucial for the cell wall biosynthesis during cell proliferation and these are the target for β-lactams. Therefore, the present study was carried out to identify the PBPs in three (low, intermediate and high MICs) groups of carbapenem resistant isolates strains of A. baumannii.

METHODS

ATCC 19606 and 20 β-lactam resistant isolates of A. baumannii were obtained. Selective identification of the PBPs was done using Bocillin FL, a non-radioactive fluorescent derivative of penicillin.

RESULTS

The fluorescence emission from Bocillin-tag in SDS-PAGE gel of native strain identified eight PBPs, with apparent molecular weight of 94, 65, 49, 40, 30, 24, 22 and 17 kDa, however, these PBPs revealed alteration in carbapenem-resistant isolates.

INTERPRETATION & CONCLUSIONS: A comparative analysis of PBPs in the resistant isolates with those of ATCC revealed a decreased expression of all PBPs except that of 65 and 17 kDa PBPs which were marginally downregulated, and simultaneous appearance of new 28 kDa PBP (in low and intermediate resistant isolates) and 36 kDa in high meropenem resistant group of A. baumannii. The present study indicated an association between alteration in PBPs and β-lactam resistance in A. baumannii.

背景与目的

鲍曼不动杆菌是一种革兰氏阴性、球菌杆菌需氧病原体，是医院内获得性感染的罪魁祸首。在最近的一段时间里，鲍曼不动杆菌已经对β-内酰胺类药物产生了耐药性，甚至对碳青霉烯类药物也产生了耐药性。青霉素结合蛋白（PBPs）在细胞增殖过程中对细胞壁生物合成至关重要，是β-内酰胺类药物的作用靶点。因此，本研究旨在鉴定三种（低、中、高 MICs）碳青霉烯类耐药鲍曼不动杆菌分离株的 PBPs。

方法

获得 ATCC 19606 和 20 株β-内酰胺类耐药鲍曼不动杆菌分离株。使用 Bocillin FL（青霉素的非放射性荧光衍生物）对 PBPs 进行选择性鉴定。

结果

在天然菌株的 SDS-PAGE 凝胶中，Bocillin 标记的荧光发射鉴定出 8 种 PBPs，其表观分子量分别为 94、65、49、40、30、24、22 和 17 kDa，但这些 PBPs 在碳青霉烯类耐药分离株中发生了改变。

解释与结论

耐药分离株与 ATCC 的 PBPs 比较分析显示，除 65 和 17 kDa 的 PBPs 略有下调外，所有 PBPs 的表达均降低，同时出现新的 28 kDa PBP（在低和中耐药分离株中）和 36 kDa 在高美罗培南耐药组的鲍曼不动杆菌。本研究表明，PBPs 的改变与鲍曼不动杆菌的β-内酰胺类耐药性之间存在关联。