鲍曼不动杆菌耐药性分析及AmpC β-内酰胺酶基因研究

Study on drug resistance and genes of AmpC β lactamases in Acinetobacter baumannii

目的:了解临床标本分离的鲍曼不动杆菌(Acinetobacter baumannii,Ab)对常见抗生素的耐药现状并研究Ab中质粒及染色体介导的AmpCβ- 内酰胺酶基因的分布特点。方法:应用VITEK 2微生物分析系统对中南大学湘雅医院2010年11月至2011年4月临床标本进行分离培养、鉴定和药物敏感性分析,采用PCR扩增方法对173株非重复Ab blaMOX,blaCMY 2,blaDHA,blaACC,blaACT 1,blaFOX,blaADC六种耐药基因进行分析。结果:173株临床分离菌株对第一、三代头孢菌素,青霉素,磺胺类复合制剂及呋喃妥因的耐药率均超过70%;对喹诺酮类药物中左旋氧氟沙星、环丙沙星耐药率分别为23.7%和89.0%;对氨基糖苷类抗生素耐药率为58.4%~85.5%;对氨曲南的耐药率为51.4%;对碳青霉烯类、第四代头孢菌素及β- 内酰胺/β- 内酰胺酶抑制剂复合物耐药率为8.7%~89.6%(其中耐药率最低的为头孢哌酮/舒巴坦)。173株Ab中携带blaADC基因的为154株(89.0%),且产blaADC基因的菌株对头孢曲松、庆大霉素、妥布霉素、复方新诺明、环丙沙星、亚胺培南的耐药率高于不产blaADC基因的菌株,两组间差异具有统计学意义(P<0.05)。未扩增出blaMOX,blaCMY 2,blaDHA,blaACC,blaACT 1,blaFOX五种耐药基因。结论:头孢哌酮/舒巴坦可作为治疗Ab感染的推荐药物。产ADC型AmpCβ- 内酰胺酶是Ab菌株对头孢曲松、庆大霉素、妥布霉素、复方新诺明、环丙沙星、亚胺培南耐药的重要原因之一。

Objective： To investigate the distribution and drug resistance ofAcinetobacter baumannii from Xiangya Hospital and to explore the genes ofAmpC β-lactamases in Acinetobacter baumannii. Methods： Acinetobacter baumannii were isolated from November 2010 to April 2011 from Xiangya Hosipital, Central South University. All strains were identified and determined the MICs of the common antibiotics by VITEK-2 System. The resisitance genes, blaMOX, blaCMY-2, blaDHA, blaACC, blaACT-1, blaFOX, blaADC were analyzed by PCR. Results： Total isolated strains were highly resistant to the first and third-generations of cephalosporin and penicillin, sulfamethoxazole, nitrofuranton （〉70%）. The resistance rate to quinolones, aminoglycosides, aztreonam, carbapenems/forth generations of cephalosporin/[^-lactam/^-lactamase inhibitor-resistant complex was 23.7%- 89.0%, 58.4%-85.5%, 51.4%, and 8.7%-89.6%, respectively. The resistance rate to cefoperazone/sulbactam was the lowest. The rate of carrying blaADC was 89.0%, and the resistance rates of blaADC-positive strains to ceftriaxone, gentamicin, tobramycin, sulfamethoxazole, ciprofloxacin, imipenem was significantly higher than that ofblaADC-negative strains （P〈0.05）. The gene of blaMOX, blaCMY-2, blaDHA, blaACC, blaACT-1, blaFOX were not detected. Conclusion： Cefoperazone/sulbactam is recommended as treatment drugs of Acinetobacter baumannii infection. ADC type AmpC ^-lactamase might be an important factor of drug resistance to ceftriaxone, gentamicin, tobramycin, sulfamethoxazole, ciprofloxacin, imipenem in Acinetobacter baumannii.