Islam M S, Rezwan F B, Khan S I
Laboratory Sciences Division, International Centre for Diarrhoeal Disease Research, Mohakhali, Dhaka, Bangladesh.
J Diarrhoeal Dis Res. 1996 Mar;14(1):37-40.
Survival of bacteria in aquatic environment is influenced by the prevailing physicochemical characteristics of water. A study was carried out to assess the effects of temperature, pH, and salinity of water on the survival of Shigella flexneri in laboratory microcosms. Survival of S. flexneri was assessed by viable counts of Shigella on MacConkey agar plates. At pH 7.0 and temperature of 4 degrees C, S. flexneri survived longer in 0.5% salinity than in salt-free distilled water, while at pH 7.0 and at higher temperatures (25 degrees C and 37 degrees C), the bacteria survived longer in distilled water than in 0.5% salinity. It was also observed that 2.0% NaCl solution was detrimental to bacterial survival at pH 8.0 and temperature of 37 degrees C. Survival times of the viable cells increased with reduction of temperatures and salinity. These findings demonstrated that survival of S. flexneri in the aquatic environment is greatly influenced by physicochemical factors.
细菌在水生环境中的存活受到水中主要物理化学特性的影响。开展了一项研究，以评估水的温度、pH值和盐度对实验室微观环境中弗氏志贺菌存活的影响。通过在麦康凯琼脂平板上对志贺菌进行活菌计数来评估弗氏志贺菌的存活情况。在pH值为7.0且温度为4摄氏度时，弗氏志贺菌在0.5%盐度下比在无盐蒸馏水中存活时间更长，而在pH值为7.0且温度较高（25摄氏度和37摄氏度）时，该细菌在蒸馏水中比在0.5%盐度下存活时间更长。还观察到，在pH值为8.0且温度为37摄氏度时，2.0%的氯化钠溶液对细菌存活有害。活菌的存活时间随着温度和盐度的降低而增加。这些发现表明，弗氏志贺菌在水生环境中的存活受到物理化学因素的极大影响。
