摘要
目的通过对呼吸道反复感染铜绿假单胞菌,久治不愈,药敏试验从全敏感、部分敏感到全耐药所留菌种染色质和质粒上的整合子Ⅰ的基因及其所携带的耐药基因盒的检测,并结合临床症状与病史分析细菌整合子的耐药特性及机制。方法用VITEKⅡ鉴定细菌、KB法药敏试验、试剂盒抽提质粒和基因组DNA经PCR扩增整合酶Ⅰ基因后琼脂糖凝胶电泳,LA-PCR扩增可变区耐药基因盒并电泳,可变区耐药基因测序,结合患者病史及临床分析耐药现象。结果该菌株在耐药前后均检测出整合子Ⅰ,耐药前全敏感时未测得耐药基因盒,多重耐药时可变区所测得的耐药基因盒有耐β-内酰胺类、CatB8、aad4以及aac(6')-Ib等耐药基因盒,分别对头孢菌素类、氯霉素类、氨基糖苷类和氨基糖苷-喹诺酮类组合耐药,还测得了MexROprD表达系统的基因盒,提示排出泵增强和外膜通透性降低的耐药机制也可以由整合子以基因盒形式摄取并表达。未测得碳青霉烯类耐药基因盒。结论该菌株在耐药前后均带有整合子Ⅰ,该整合子在铜绿假单胞菌耐药中起重要作用。
Objective To monitor the integronI and gene cassettes at the bacterial DNA by using the bacteria Pseudomonas aeruginosa,which infected repeatedly the patient at the respiratory tract, who didn＇t recover although being treated medicaly in the hospital for a long time, and to analyze the resistant pattern and mechanisms of this bacteria combined with clinical history and symptoms. These bacteria Pseudomonas aeruginosa has developed resistances against the regularly standard antibiotics from the whole susceptibility to the partial one and till to all resistance. Methods To identify the bacteria with VITEK Ⅱ ,KB-Agar Diffusion Test for antibiotic susceptibility tests,DNA and plasmid extraction and purification kits for bacterial DNA and plasmid extraction, to amplify and integronI by using PCR while to detect gene cassettes in variable region of integronl by LA PCR, Agarose electrophorcsis of PCR and LA PCR products, DNA sequencing by Firma Invitrogen and analyzed by Gen-Bank Data base of BLAST, and analyze the resistance pattern combined with the clinical history and symptoms of the patient. Results There exists integronl at the Pseudomonosa before and after becoming resistant. Gene cassettes including β-1actamase cassettes and CatB8,aad4 and aac（6＇）-Ib cassettes could not detect all the antibiotics during susceptible period. Several gene cassettes could be detected during the antibiotic multi resistant period. They are resistant to β-lactam（cephalosporins）, chloramphcnicols, aminoglycosides and ami noglycoside quinolones antibiotics respectively. Surprisingly, we have also detected the cassettes of McxR-OprD system. It means that the integronI can not only actively take gene cassettes for antibiotic resistance, but also can take and express cassettes with another resistant mechanism other than hydrolyze enzymes,e, g. increasing the function of the efflux pump in bacteria or/and reducing the outer membrane permeability of the bacteria against the antibiotics. Carbapenem-resistance gene cassettes were not detected and plasmid extraction was not successful. Conclusion The pseudomonas aeruginosa, which infected the patient repeatedly, has integronI at its chromosome. This IntegronI was significant for the resistance functions in the studied pseudomonas aeruginosa.
出处
《国际检验医学杂志》
CAS
2010年第1期19-21,共3页
International Journal of Laboratory Medicine
关键词
假单胞菌
铜绿
整合子类
抗药性
细菌
基因表达
Pseudomonas aeruginosa
Integrons
Drug resistance,Bacterial
Gene expression
