头孢他啶耐药褪色沙雷菌β-内酰胺酶检测及耐药性分析

目的了解头孢他啶耐药褪色沙雷菌临床分离株产超广谱β-内酰胺酶（ESBLs）、头孢菌素酶（AmpC）及碳青霉烯酶情况,并分析其对14种常见抗菌药物的耐药性。方法 ESBLs、AmpC采用三维试验进行检测;碳青霉烯酶采用改良Hodge试验进行检测;药物敏感试验采用K-B法测定。结果 112株头孢他啶耐药褪色沙雷菌ESBLs、AmpC检出率较高;未发现同产ESBLs、AmpC及碳青霉烯酶3种酶的菌株。产ESBLs、AmpC褪色沙雷菌对亚胺培南、美罗培南的耐药率低于6.00%,与非产酶菌株相比,差异无统计学意义（P〉0.05）;对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢比肟的耐药率均明显高于非产酶菌株（P〈0.01）。另外,同产ESBLs＋AmpC头孢他啶耐药褪色沙雷菌分离株与单产酶株相比,对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、头孢比肟、复方新诺等多种抗生素耐药率差异有统计学意义（P〈0.01或P〈0.05）。碳青霉烯酶株对14种常见抗生素多重耐药或泛耐药。结论我院头孢他啶耐药褪色沙雷菌分离株对常用抗菌药物的耐药性较高,耐药性的产生与细菌产多种β-内酰胺酶有关。

Detection of beta-lactamase and drug-resistance in ceftazidime-resistant Serratia marcescen

Objective To learn the positive-rates of extended-spectrum β-lactamases（ ESBLs）,cephalosporinase（ AmpC） and Carbapenemase in ceftazidime-resistant Serratia marcescen and the resistance rates to 14 common antibiotics. Methods AmpC and ESBLs were detected with three dimensional test; carbapenemase was confirmed by modified Hodge test（ MHT）. Drug sensitivity was detected by using K-B method. Results The detection rates of ESBLs and AmpC were high,but no ESBLs plus AmpC plus carbapenemase-producing strain had been detected.The resistance rates to minocycline（ 30. 36%） and moxifloxacin（ 25. 00%） were lower in ceftazidime-resistant Serratia marcescen compared with ceftazidime-susceptible strains. The resistance rates to imipenem and meropenem in ESBLs-producing,AmpC-producing and ESBLs ＋ AmpC producing strains were lower than 6. 00%,which was not significantly different from those of non-enzyme-producing strains（ P 〉0. 05）. The resistance rates to Cefoperazone /Shubatan,piperacillin /tazobactam,and cefepime were significantly different（ P 〈0. 01）. And the resistance rates to Cefoperazone /Shubatan,piperacillin /tazobactam,cefepime and cotrimoxazole of ESBLs ＋ AmpC-producing strains were significantly different from those of ESBLs-producing or AmpC-producing strains（ P〈 0. 01 or P〈 0. 05）. The carbapenemase-producing Serratia marcescen strains were highly resistant to 14 common antibiotics. Conclusion The drug resistance rates of ceftazidime-resistant Serratia marcescen isolates in our hospital to common antibiotics are high,which is related to production of a variety of β-lactamase enzymes.