志贺菌临床分离株AcrAB-TolC外排泵mRNA转录水平与氟喹诺酮耐药的相关性

Relationship between the m RNA transcription levels of AcrAB-TolC efflux pump in Shigella from clinical source and fluoroquinolone resistance

目的探讨志贺菌临床分离菌株Acr AB-Tol C外排泵的3个组成基因(acr A、acr B、tol C)m RNA转录水平与其氟喹诺酮耐药水平。方法收集2009至2015年于天津医科大学总医院、天津医科大学第二医院和天津市儿童医院3家三甲医院就诊腹泻患者的非重复粪便样本,分离培养获得192株志贺菌临床分离菌株,采用K-B纸片法对所有菌株进行体外药敏试验;根据药敏试验结果,将志贺菌株分为氟喹诺酮耐药组和氟喹诺酮全敏感组;应用实时荧光定量PCR(RT-PCR)技术,检测上述两组志贺菌临床分离株Acr AB-Tol C外排泵基因在m RNA转录水平的相对表达量,使用SPSS 17.0软件对结果进行统计学分析。结果氟喹诺酮耐药组志贺菌株共计9株(对3种及3种以上氟喹诺酮耐药的菌株),依次编码为F2、N8、F44、157、187、368、1113、3171和3327,氟喹诺酮全敏感组志贺菌株共计9株,依次编码为F13、1、22、174、186、377、1506、3283和3326;耐药组外排泵acr A基因的m RNA转录水平高于全敏感组菌株,差异具有统计学意义(t=2.97、P=0.02);耐药组外排泵acr B和tol C基因的m RNA转录水平均值虽然高于全敏感组相应基因m RNA转录水平,但差异均无统计学意义(t=2.84、P=0.30,t=1.17、P=0.29)。结论受试菌株外排泵acr A基因m RNA转录水平增高与氟喹诺酮耐药存在一定的关联。

Objective To investigate the relationship between the transcriptional levels of messenger RNA （mRNA） from component genes （acrA, acrB, tolC） of the efflux pump AcrAB-TolC of clinical isolates of Shigellaflexneri and the level of fluoroquinolone resistance. Methods Total of 192 clinical Shigella isolates were collected from non-repetitive faeces of diarrhea patients during 2009 to 2015 from 3 grand three hospitals in Tianjin, which were The General Hospital of Tianjin Medical Univercity, The Second Hospital of Tianjin Medical Univercity and The Children＇s Hospital in Tianjin. Antibiotic susceptibility of the Shigella clinical isolates were detected by K-B disk diffusion. The strains were divided into the fluoroquinolone resistant group and full fluoroquinolone sensitive group, according to susceptibility to fluoroquinolone. The mRNA transcription of AcrAB-TolC efflux pump of the two groups of strains determined by real-time quantitative PCR （RT-PCR）. And the SPSS 17.0 software was used for statistical analysis. Results There were 9 isolates in fluoroquinolone resistance group, which were resistant to three and above kinds of fluoroquinolone. And the number in the fluoroquinolone resistance group were F2, N8, F44, 157, 187, 368, 1113, 3171 and 3327. While there were 9 isolates in fluoroquinolone full-sensitive group. And the number were F13, 1, 22, 174, 186, 377, 1506, 3283 and 3326. The mRNA transcription level of acrA in the resistant group was higher than that of the full-sensitive group, with significant difference （t =2.97, P = 0.02）. Although the mRNA transcription levels of acrB and tolC in the resistant group were higher than those of the full-sensitive group, but with no significant difference （t = 2.84, P = 0.30; t = 1.17, P = 0.29）. Conclusions There was a certain correlation between the high mRNA transcription level of acrA and the resistance of fluoroquinolones in Shigella.