The Response Characteristics Of Four Pathogenic Aeromonas Hydrophila Trains To Temperature And PH

The paper used spectrophotometry to explore the single factor and interactioneffects of temperature and pH on the growth of four Aeromonas hydrophila strainsZHHYZ-1,ZHHYZ-2,ZHHYZ-3and ZHHYZ-4, which were isolated from sick turtles.The results showed that:(1) The optimum growth temperature span of the four strainswere all25～35℃, Only ZHHYZ-1can grow under the condition of high temperature45℃;(2)The optimum growth pH span of ZHHYZ-1,ZHHYZ-3and ZHHYZ-4were6～9, while ZHHYZ-2was6～8;(3) There existed interaction effects betweentemperature and pH on the growth of the four strains. The effecs of temperature and pHalone and its combined effects both had an significant influence on the growth of fourstrains（P<0.05），but under different combinations, temperature and pH had differenteffects on the four strains.PCR and Rt-PCR techniques were used to explore the single factor and interactioneffect of temperature and pH on the detection and expression of the virulence gene OMP,AHH, Aha and AerA of the four strains. The results showed that:(1) The effects oftemperature and pH alone and its combined effects both had no influence on thedetection of the four strains virulence gene OMP, AHH, Aha and AerA;(2) Temperatureand pH had an influence on the expression of four strains AerA, except ZHHYZ-1AerAwas expressed at the interaction of pH6with30℃, it was only expressed undercombination of preference temperature and inaptitude pH,25℃was the limited factor ofAerA expression, ZHHYZ-2AerA didn’t expressed at the interaction of pH5,10with25℃, ZHHYZ-3and ZHHYZ-4AerA didn’t expressed at the interaction of pH5with25℃;(3) Temperature and pH had no influence on the four strains virulence gene OMP,Aha expression, only the AHH of ZHHYZ-1didn’t expressed at the interaction of pH8with30℃。K-B paper agar diffusion method was used to explore the single factor andinteraction effect of temperature and pH on the four strains’ amikacin and norfloxacinsensitivity at suitable conditions. the results showed that:(1) There were interaction effects between temperature and pH on the four strains’ amikacin and norfloxacinsensitivity, the effects of temperature and pH alone and its combined effects both had ansignificant influence on the strains’ amikacin and norfloxacin sensitivity(P<0.05);(2)ZHHYZ-1’ amikacin sensitivity was influenced more by pH than temperature, whileZHHYZ-1’ norfloxacin sensitivity was influenced more by temperature than pH.ZHHYZ-2’ amikacin and norfloxacin sensitivity was opposite to that of ZHHYZ-1.Amikacin and norfloxacin sensitivity of ZHHYZ-3and ZHHYZ-4were both influencedmore by pH than temperature.