bla_(CTX-M)基因与氨基糖苷类抗生素耐药水平的相关性

Correlation between bla_(CTX-M) gene and aminoglycoside antibiotic resistance level

目的分析β-内酰胺类耐药基因在肺炎克雷伯菌中的分布并评估这些基因对抗生素耐药水平的影响。方法选择76株肺炎克雷伯菌临床分离菌株,用K-B纸片法和MIC法检测抗生素的耐药性;用PCR法检测肺炎克雷伯菌株中β-内酰胺类抗生素的相关基因,RT-PCR的方法检测β-内酰胺类基因的表达。结果 76株肺炎克雷伯菌中,ESBLs相关基因主要为SHV(45/76,59.21%)、TEM(27/76,35.53%)和CTX-M(38/76,50.00%);携带SHV基因菌株对阿米卡星的耐药率(37.78%)明显高于非携带SHV基因菌株(16.13%)(P<0.05)。携带CTX-M基因(76.32%)和TEM基因(70.37%)的菌株对庆大霉素的耐药率明显高于不携带CTX-M基因(34.21%)和TEM基因(46.94%)的菌株(P<0.05)。RT-PCR的结果显示,阿米卡星和庆大霉素耐药株的CTX-M基因mRNA的表达率均明显高于敏感株。结论β-内酰胺类基因与氨基糖苷类抗生素的耐药相关,CTX-M基因与肺炎克雷伯菌对氨基糖苷类抗生素的耐药水平相关。

Objective To analyze the distribution of β-1actam resistance genes in Klebsiella pneumoniae （ K. pneumoniae） and assess the impact of these genes on the levels of antibiotics resistance. Methods Seventy-six clinically isolated K. pneumoniae strains were tested for their resistance to antibiotics using K-B disc diffusion and minimum inhibitory concentration （MIC） methods. PCR and RT-PCR used for detection of the β-1actamase genes and mRNA expression of genes. Results In the seventy-six K. pneumoniae strains, the primary ESBL-related genes were SHV （45/76, 59.21% ）, TEM （27/76, 35.53% ） and CTX-M （38/76, 50.00% ）. The amikacin resistance rate of strains carrying the SHV gene （37.78%） was significantly higher than that of strains without the SHV gene （ 16.13% ） （P 〈 0.05）, and the gentamycin resistance rate of strains carrying the CTX-M gene （76.32%） and TEM gene （70.37%） was significantly higher than that of strains without the CTX-M gene （34.21%） and TEM gene （46.94%） , respectively （P 〈 0.05）. Further reverse transcription polymerase chain reaction analysis indicated that higher expression of mRNA of blacCTX-M gene were commonly seen in the amikacin and gentamycin resistance clinical isolates. Conclusion ESBLs genes closely associate with aminoglycoside drug resistance and the CTX-M gene enhance the resistance level of K. pneumoniae to aminoglycoside antibiotics such as amikacin and gentamycin.