鲍曼不动杆菌耐药性与β-内酰胺酶基因研究

目的：了解临床分离鲍曼不动杆菌的耐药性和β-内酰胺酶基因分布情况。方法：采用VITEK-60全自动细菌分析仪对215株鲍曼不动杆菌临床分离株进行药敏检测,并通过特异性的PCR和DNA序列测定方法检测试验菌的β-内酰胺酶相关基因。结果：鲍曼不动杆菌对酶抑制剂复合制剂头孢哌酮/舒巴坦的敏感率最高,为54.1%,对亚胺培南、美洛培南的敏感率分别为46.4%、39.3%,对其他药物的敏感率均很低,对三代头孢的敏感率均低于20%;215株鲍曼不动杆菌中,27株扩增到超广谱β-内酰胺酶（ESBLs）基因,占12.6%,包括TEM 16株,占7.4%,SHV 4株,占1.9%,CTX-M-1 4株,占1.9%,OXAⅡ3株,占1.4%,经测序分型分别为TEM-1型、SHV-1型、OXA-21型、CTX-M-15型和CTX-M-22型,未检测到VEB、GES、CTX-M-2、CTX-M-8、CTX-M-9、TLA、IBC、OXA-10、OXAⅠ、OXAⅢ、OXAⅣ、OXAⅤ等基因。129株扩增到头孢菌素酶（AmpC）基因,占60.0%,其中ADC阳性82株,占38.1%,DHA、EBC、ACC、CIT基因阳性株分别为35株（占16.3%）、8株（占3.7%）、3株（占1.4%）和1株（占0.5%）,未检测到MOX、FOX、CARB基因;215株菌株中检出OXA-23阳性98株,占45.6%。结论：临床分离鲍曼不动杆菌耐药严重,其携带TEM、ADC、DHA、OXA-23等多种β-内酰胺酶相关基因。

Study on the resistance and genotyping of β-lactamases in Acinetobacter baumannii

Objective：To understand the drug-resistance and the distribution of β-lactamases genes in Acinetobacter baumannii.Methods：Antimicrobial susceptibility was tested with Vitek60-AMS.Genotypes of β-lactamase were analysed with polymerase chain reaction（PCR） and verified by DNA sequencing.Results：Of the 215 Acinetobacter baumannii strains,54.1% was susceptible to cefoperazone/sulbactam,46.4% and 39.3% were susceptible to imipenem and meropenem,respectively.But these strains exihited lower susceptible to other antibiotics,especially to third generation cephalosporins（20%）;of the 27 ESBLs positive strains,TEM-type was encoded in 16（7.4%）,SHV,CTX-M-1,OXAⅡtypes were encoded in 4（1.9%）,4（1.9%）and 3（1.4%）,respectively.The subtypes were TEM-1,SHV-1,CTX-M-15,CTX-M-22 and OXA-21.This study did not dig out VEB,GES,CTX-M-2,CTX-M-8,CTX-M-9,TLA,IBC,OXA-10,OXAⅠ,OXAⅢ,OXAⅣ and OXAⅤgenes in all strains.AmpC was encoded in 129（60.0%）,including ADC 82（38.1%）,DHA 35（16.3%）,EBC 8（3.7%）,ACC 3（1.4%） and CIT 1（0.5%）,respectively.No MOX,FOX and CARB genes were detected.OXA-23 was encoded in 98（45.6%）in 215 strains.Conclutions： The multidrug resistance of Acinetobacter baumannii from clinical isolation is a serious issue.And these isolations harbor all kinds of β-lactamase resistance genes,including TEM,ADC,DHA,OXA-23 and so on.