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目的调查本院妇科肿瘤患者铜绿假单胞菌rmtB及I类整合子基因分布及与耐药谱关系。方法收集妇科肿瘤患者2010年1月-2013年1月分离120株非重复铜绿假单胞菌,采用PCR及DNA测序检测rmtB和I类整合酶基因(int1),PCR检测整合子可变区。结果铜绿假单胞菌对头孢噻肟和头孢曲松耐药率较高,分别为86.7%和90%,而对其他抗生素耐药率为29.2%~73.3%。筛选出88株对氨基糖苷类抗生素耐药铜绿假单胞菌中rmtB阳性菌35株(39.7%)。rmtB阳性菌intlI阳性率为100%(35/35),含有9种整合子类型,以携带400 bp、1 000 bp大小片段基因盒为主,另有三株为空盒。质粒接合试验均未成功。结论 rmtB广泛存在于铜绿假单胞菌中,导致对多种氨基糖苷类抗生素高水平耐药。rmtB不存在于I类整合子中,但或可与I类整合子通过染色体联合传播,I类整合子可变区呈现多态性分布。
Objective To investigate the gene distribution of rmtB and class I integrons of Pseudomonas aeruginosa in gynecologic oncology patients in our hospital and its relationship with drug resistance spectrum. Methods A total of 120 non-repetitive Pseudomonas aeruginosa isolates were collected from January 2010 to January 2013 in gynecologic oncology patients. The rmtB and type I integrase genes (int1) were detected by PCR and DNA sequencing. The integron variable regions were detected by PCR. Results The rates of resistance to cefotaxime and ceftriaxone in Pseudomonas aeruginosa were 86.7% and 90% respectively, while those in other antibiotics ranged from 29.2% to 73.3%. Thirty-five strains of rmtB-positive bacteria (39.7%) were detected in 88 strains of aminoglycoside-resistant Pseudomonas aeruginosa. The positive rate of intlI was 100% (35/35) for rmtB-positive bacteria, which contained 9 integron subtypes. The majority of rmtB-positive bacteria contained 400 bp and 1 000 bp fragments. The other three were empty. Plasmid conjugation experiments were unsuccessful. Conclusion rmtB is widespread in Pseudomonas aeruginosa, resulting in high levels of resistance to various aminoglycoside antibiotics. rmtB does not exist in class I integrons, but can be transmitted through chromosome association with class I integrons, and class I integrons exhibit polymorphic distribution.