阴沟肠杆菌产AmpC酶和ESBLs的检测及耐药性分析

Analysis of antibiotic resistance and detection of AmpC producing and ESBLs producing E.cloacae

目的明确阴沟肠杆菌产头孢菌素酶(AmpC酶)和超广谱β-内酰胺酶(ESBLs)的情况,分析细菌产酶与药物耐药间的关系,指导临床合理用药。方法非重复阴沟肠杆菌共174株采用Microscan walkaway-40SI全自动细菌鉴定与药敏分析仪进行细菌鉴定及药敏试验;采用多底物协同-拮抗法(MSSAT)检测ESBLs和AmpC酶。结果 174株阴沟肠杆菌中,单产AmpC酶92株(52.87%),其中高诱导型25株,部分去阻遏型33株,完全去阻遏型22株;同时产AmpC酶和ESBLs 54株(31.03%);单产ESBLs 1株(0.57%);AmpC酶和ESBLs均不产有27株(15.52%);阴沟肠杆菌产酶株的耐药率明显高于不产酶株的耐药率(P<0.05),同时产AmpC酶和ESBLs菌株的耐药率高于单产AmpC酶株的耐药率(P<0.05);产AmpC酶和ESBLs菌株对头孢曲松、头孢噻肟、哌拉西林的耐药率均高于92.0%,对氨曲南耐药率高达88.9%,对阿米卡星耐药率较低(14.8%),对亚胺培南耐药率为0%。结论阴沟肠杆菌以产AmpC酶为主,单产ESBLs菌株少,同时产AmpC酶和ESBLs的菌株对三代头孢菌素、单环类、青霉素类具有高度耐药性,对碳青霉烯类药物敏感;碳青霉烯类抗菌药物依然是治疗多重耐药阴沟肠杆菌感染的首选。

Objective To determine the situation of E.cloacae for producing extented spectrum beta-lactamases（ESBLs）and cephalosporinase（AmpC）and to analyze the relationship between bacterial enzyme production and drug resistance for guiding rational drug use in clinic.Methods A total of 174 strains of non-repetitive E.cloacae were performed the identification and drug susceptibility test by adopting the Microscan walkaway 40 SI fully automatic bacterial identification and drug susceptibility analyzer;the multi-substrates synergy-antagonize test（MSSAT）was used for detecting ESBLs and AmpC.Results Among 174 strains of E.cloacae,92strains（52.87%）only produced AmpC,25 strains produced highly inducible AmpC,33 strains produced partially derepressed AmpCs and 22 strains produced completely derepressed AmpCs;54strains（31.03%）produced both AmpC and ESBLs;1strain（0.57%）only produced ESBLs;27strains（15.52%）did notproduced AmpC and ESBLs.The drug resistance rate of enzyme producing E.cloacae strains was significantly higher than that of non-enzyme producing E.cloacae strains（P〈0.05）.The resistance rate of both AmpC producing and ESBLs producing strains was significantly higher than that of only AmpC producing strains（P〈0.05）.The resistance rates of E.cloacae producing both AmpC and ESBLs to ceftriaxone,cefotaxime and piperacillin were more than 92.0%,which to aztreonam was up to 88.9%,which to amikacin was relatively low（15.1%）and which to imipenem was0%.Conclusion E.cloacae is dominated by AmpC producing,simply producing ESBLs strains is little.Both AmpCs and ESBLs producing E.cloacae strain shows high drug resistance to third generation cephalosporin,single ring antibiotics and penicillins,and sensitive to carbapenem drugs.Carbapenem antibacterial drugs are still the first choice for treating multi-drug resistant E.cloacae infection.