持续高产型AmpC酶的产生与抗菌药物应用关系的研究

Relations Between Emergence of Constitutive High Expression AmpC β-Lactamase and Therapy of Antibiotics

目的了解抗菌药物对革兰阴性杆菌AmpC酶从诱导耐药型向持续高产型转变的影响作用。方法筛选携带诱导型菌株的患者作为研究对象,定期收集其感染标本,至转化为持续高产型,并对其菌种、基础疾病、期间抗菌药物使用种类及用量进行统计分析。结果 152株诱导型菌株中,68株转化为持续高产型,其中12株阴沟肠杆菌全部转化,转化率达100.0%;脑梗死患者的细菌更易转化(83.3%,OR=7.1);头孢菌素类(95.3%/64.6%)、多肽类(18.95%/15.5%)、青霉素类+β-内酰胺酶抑制剂(128.8%/276.0%)以及碳青酶烯类+β-内酰胺类(58.9%/82.3%)抗菌药物的用量对持续高产型AmpC酶的产生有着显著的影响(P<0.05),其中后两者剂量与转化率呈正相关,前两者呈负相关。结论大剂量青霉素类+β-内酰胺酶抑制剂和碳青酶烯类+β-内酰胺类抗菌药物可能会促进诱导型产酶菌株转变为持续高产型产酶菌株。

OBJECTIVE To investigate the influence of antibiotics to produce constitutive high expressed AmpC β-lactamases by Gram-negative bacilli.METHODS Selecting the bacilli which were resistant to cefoxitin and negative in three-dimention test from the patients with nosocomial infections.Collecting the same patients＇samples for three-dimention test until they were positive.Recording the bacteria species,underlying diseases,the sorts and dosage of antibiotics.RESULTS Of 152 strains,68 was positive.Twelve strains of Enterobacter cloacae were all changed（100%）.The bacteria from the cerebral patients were prone to turn into the constitutive high expression（P〈0.05）,the positive rate was 83.3%（10/12,OR=7.1）.used penicillins plus β-lactamase inhibitors（128.8/276.0）and carbapenem plus β-lactams（58.9/82.3）were positively related with the dosage of antibiotics,while cephalosporins（95.3/64.6）and peptide（18.9/15.5）were negatively related.CONCLUSIONS High dose penicillins＋β-lactamase inhibitors and carbapenem＋β-lactams may promote the producetion of durative high expressed AmpC β-lactamases.