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 Shigella flexneri and the level of fluoroquinolone resistance.

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.

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).

There was a certain correlation between the high mRNA transcription level of acrA and the resistance of fluoroquinolones in Shigella.