重型肝炎患者苏云金杆菌的耐药机制研究

Resistant mechanisms in Bacillus thuringiensisof a patient with severe chronic hepatitis

目的研究重型肝炎患者苏云金杆菌(Bt)的耐药机制。方法应用美国BD公司的Phoenix NMIC/ID-55鉴定/药敏板进行鉴定与细菌药敏试验,应用PCR法检测Bt的耐药基因,并经测序及同源性分析证实其分布。结果该株病原菌经16SrRNA测序及同源性分析(GenBank注册号为FJ932761)证实为Bt;对氨苄西林、万古霉素、替考拉宁、环丙沙星、呋喃妥因、四环素、夫西地酸、利奈唑胺敏感,对青霉素、苯唑西林、红霉素、克林霉素、喹奴普汀/达福普汀、庆大霉素、妥布霉素、阿米卡星、磺胺甲噁唑/甲氧苄啶、头孢西丁、莫匹罗星等药耐药;PCR扩增1种AMEs耐药基因阳性,经测序和同源性分析证实为ant(3″)-Ⅰ,于GenBank注册号为FJ644661。结论Bt对氨基糖苷类耐药机制主要与ant(3″)-Ⅰ基因有关。

OBJECTIVE To study the resistant mechanisms of Bacillus thuringiensis（Bt） in the blood of a patient with severe hepatitis B.METHODS The susceptibility of antimicrobial agents was detected by Phoenix NMIC/ID-55,and the resistant gene of Bt were detected with PCR and its distribution was confirmed after DNA sequencing and homology analysis.Thirty-nine resistant genes including 29 β-lactamases genes,6 aminoglycoside-modifying enzymes（AMEs）genes,chlorhexidine-sulfaciazine resistant gene（qacE△1-sul1）and intergron（intI1、2、3）and so on.RESULTS The pathogen was identified as Bt by 16S rRNA-PCR-DNA sequencing（GeneBank No.：FJ932761）;it was susceptible to ampicillin,vancomycin,teicoplanin,fusidic acid,linezolid,ciprofloxacin,nitrofurantoin and tetracyclin,but resistant to penicillin,oxacillin,trimethoprim/sulfamethoxazole,cefoxitin,mupirocin,erythromycin,clindamycin,QD,tobramycin,gentamicin and amikacin;There was one kind of resistant gene which was positive（ant（3″）-Ⅰ,GeneBank No.FJ644661）.Thirty-eight kinds of resistant genes were negative.CONCLUSION The resistant mechanism of the Bt to aminoglycoside is mainly related to ant（3″）-Ⅰ.