产ESBLs鲍曼不动杆菌的耐药特性、质粒谱及耐药基因型

Resistance,plasmid profiles and gene typing of ESBLs-producing Acinetobacter baumannii

目的了解并研究产超广谱β-内酰胺酶(ESBLs)鲍曼不动杆菌的流行、耐药特点及质粒图谱,对产ESBLs菌株进行基因分型。方法先后用nitrocefin纸棒、最低抑菌浓度(M IC)初筛法和纸片扩散确认法从临床分离的鲍曼不动杆菌中检测产ESBLs菌株,用凝胶电泳分析其质粒图谱,并用聚合酶链反应(PCR)对产ESBLs基因进行分型。结果93株鲍曼不动杆菌中,对β-内酰胺酶类抗菌药物耐药47株(79.66%),中度敏感12株(20.34%);产ESBLs菌株有16株,占17.20%。产ESBLs鲍曼不动杆菌对头孢曲松、头孢他啶、头孢唑肟、头孢吡肟、氨曲南、庆大霉素、妥布霉素、磺胺甲唑、环丙沙星和阿米卡星的耐药率均显著高于非产ESBLs菌株(P<0.05)。保留的15株产ESBLs菌具有4种质粒谱,主要为Ⅰ型和Ⅲ型;它们均携带1～2种TEM型或SH V型或PER型β-内酰胺酶基因,且80%携带OXA-23型碳青霉烯酶基因。结论产ESBLs鲍曼不动杆菌常为多重耐药菌,耐药率与产ESBLs密切相关;同一克隆株在同一病房有流行趋势;本院流行株均携带2～3种耐药基因型,主要为TEM型、PER型β-内酰胺酶基因和OXA-23型碳青霉烯酶基因。

Objective To study the prevalence, drug resistance, plasmid profiles and initial gene typing of extended spectrum β-lactamases （ESBLs） producing Acinetobacter baumannii. Methods The ESBLs producing strains among clinic isolates of A. baumannii were detected by nitrocefin, screened by minimal inhibitory concentration （MIC） method and confirmed by a disc dilution confirmatory test. Then the analysis of the plasmid profiles was performed by gel electrophoresis. In further test, the initial typing of ESBLs was conducted by PCR. Results In 93 isolates of A. baumannii, the resistant rate and the intermediate rate were 79.66% and 20. 34% respectively. There were 16 ESBLs producing strains and accounted for 17.20%. The drug resistant rate of ESBLs producing strains to ceftriaxome, ceftazidime, ceftizoxime, aztreonam, gentamicin, tobramycin, sulfamethoxazole, ciprofloxaxin, and amikacin were significantly higher than ESBLs negative strains （ P〈0. 05）. There were 4 kinds of plasmid profiles in 15 preserved strains, mainly were type Ⅰ and type Ⅲ; they all carried Ⅰ or 2 kinds of TEM related genes or SHV related genes or PER related genes. 80% isolates carried OXA-23 genes. Conclusion ESBLs producing strains usually were muti-drug resistance and the drug resistant rate was closely associated with ESBLs. In the same ward, the epidemic strains were the same clone. They all carried 2 or 3 genes, mainly were TEM related genes or PER related genes and OXA-23 genes.