Barrett T J, Blake P A
J Clin Microbiol. 1981 Jan;13(1):126-9. doi: 10.1128/jcm.13.1.126-129.1981.
Hemolytic Vibrio cholerae biotype El Tor strains were isolated in the United States in 1973 and 1978 after they had supposedly disappeared worldwide during the 1960s and 1970s. We decided to examine the change in prevalence of hemolytic El Tor strains since the beginning of the seventh pandemic and evaluate the usefulness of hemolytic activity as an epidemiological marker. A total of 48 isolates of V. cholerae biotype El Tor isolated in the Eastern Hemisphere between 1960 and 1979, along with 1 Texas (1973) and 38 Louisiana (1978) isolates, were tested for hemolytic activity by each of four methods. One method (utilizing heart infusion broth with 1% glycerol) was slightly superior for detecting hemolytic activity. Titers obtained with this method ranged from less than 2 to 1,024. Of 13 (76.9%) strains from the earliest part of the current pandemic, 10 were hemolytic, compared with 1 of 26 (3.8%) strains isolated in the period from 1966 to 1979 in the Eastern Hemisphere, indicating that nonhemolytic El Tor strains have replaced the hemolytic variety there. In contrast, all 38 Louisiana isolates and the Texas isolate were strongly hemolytic. Hemolytic activity was concluded to be a useful epidemiological marker.
溶血性霍乱弧菌埃尔托生物型菌株在20世纪60年代和70年代据推测已在全球消失后，于1973年和1978年在美国被分离出来。我们决定研究自第七次霍乱大流行开始以来溶血性埃尔托菌株的流行率变化，并评估溶血活性作为一种流行病学标志物的实用性。对1960年至1979年在东半球分离出的48株霍乱弧菌埃尔托生物型菌株，以及1株得克萨斯州（1973年）和38株路易斯安那州（1978年）的菌株，采用四种方法分别检测其溶血活性。其中一种方法（使用含1%甘油的心脏浸液肉汤）在检测溶血活性方面略胜一筹。用该方法获得的效价范围从小于2到1024。在当前大流行最早阶段的13株菌株（76.9%）中，有10株具有溶血活性，相比之下，在1966年至1979年期间在东半球分离出的26株菌株中有1株（3.8%）具有溶血活性，这表明非溶血性埃尔托菌株已在那里取代了溶血性菌株。相比之下，所有38株路易斯安那州的分离株和得克萨斯州的分离株都具有很强的溶血活性。得出结论，溶血活性是一种有用的流行病学标志物。
