The Study Of Relationship Between AcrAB-TolC Efflux Pump Expression Level And Fluoroquinolone Resistance In Shigella Clinical Isolates

Objective:To analysis the epidemic serotypes of Shigella strains and the change of their antibiotic resistance characterstics in Tianjin,China. To investigate the relationship between the AcrAB-TolC pump and the expression of drug-resistant strains. Methods:A total of 192 clinical isolates of shigella identified in Tianjin during the years 2009-2015 were studied. 1,The serum agglutination method was used to determine the strains of serum group. Antibiotic susceptibility were detected by K—B disk diffusion method. 2,Application of naphthalene nalidixic acid, ciprofloxacin, levofloxacin, ofloxacin and norfloxacin 5 kinds of antibiotics screened 9 strains of multiple fluoroquinolone resistant(resistant to three or more than 3 fluoroquinolones antibiotics) strain(strain No. followed by F2, N8, F44, 157, 368, 187, 1113, 3171, 3327) to form a resistance group, and randomly selected 9 strains of fluoroquinolone sensitive strains(strain No. followed by F13, 1, 22, 174, 186, 377, 1506, 3283, 3326) sensitive group. 3, Using real-time fluorescence quantitativeRT- PCR technology to detect the expression of efflux pump gene of AcrAB-TolC efflux pump gene in the drug resistant group and the sensitive group, using SPSS17.0 software to analyze the results. Results:1.The strain type: 192 strains of Shigella isolates, sonnei Shigella(Group D) 98 strains(51%); Fu Shi Shigella(B group), 83 strains(43%); Shigella boydii(Group C) and Shigella flexneri(group A) respectively 9 and 2 strains.2. Drug sensitivity test: 192 strains of Shigella clinical isolates of multiple drug resistance rate of 95%. The rate of first generation quinolone nalidixic acid resistant highest was 97% for other antibiotic resistance rate reduced accordingly, including tetracycline, ampicillin and trimethoprim sulfamethoxazole resistance rate followed by 78%, 77% and 73%. The three generation cephalosporin resistance rate is low(less than 5%), and there was no Shubatan and imipenem resistant strains of cefoperazone.3. The real-time fluorescence quantitative RT-PCR: The expression level of acrA in the resistant group was higher than that in the susceptible group, and the difference was statistically significant(P < 0.05); The expression levels of acrB and tolC in the resistant group were higher than that in the susceptible group, but the difference was not statistically significant(P > 0.05).Conclusion:2009-2015, Tianjin city, three hospitals in clinical isolates of Shigella serotypes of Shigella sonnei. Secondly, Shigella flexneri, also abalone and Shigella isolates in 2015 separation 9 and 2 strains. Shigella resistant to commonly used antibiotics rate is higher, multi drug resistant strain ratio as high as 95% and high rate to tetracycline, ampicillin and trimethoprim sulfamethoxazole resistance. Shigella clinical isolates of acrAB-tolC efflux pump expression associated with mefloquine nogs antibiotic resistance.