对243株禽源大肠杆菌分离株进行血清耐受试验、菌毛化大肠杆菌血凝试验和温度敏感性血凝素试验,在这些分离株中,高度血清耐受、中等血清耐受、轻度血清耐受和血清敏感菌株分别占受试菌株的57.2%(139/243)、28.8%(70/243)、10.3%(25/243)和3.7%(9/243)。在37℃细菌培养物与鸡红细胞凝集试验中,甘露糖敏感血凝(MSHA)和甘露糖耐受血凝(MRHA)菌株分别占受试菌株的64.6%(157/243)和5.8%(14/243);与豚鼠红细胞凝集试验中,MSHA和MRHA菌株分别占受试菌株的74.9%(182/243)和2.9%(7/243),其中与鸡红细胞凝集试验MSHA菌株中,MSHA阳性菌株占高致病株的69.5%(132/190),MRHA阳性菌株占低致病株的22.2%(2/9),两者差异极显著(p〈0.01)。在温度敏感性血凝素试验中,MRHA菌株为112株,占分离株的46.1%,其中01、02和078血清型的高致病株占所在血清型分离株的83%~100%,而其它血清型的高致病株仅占57%左右,差异显著(p〈0.05)。结果显示禽源大肠杆菌的致病性与其血清耐受能力、鸡红细胞MSHA菌毛的表达和温度敏感性血凝素的表达呈一定的相关关系。
Avian E.coli isolates in China were characterized for serum resistance, mannose sensitive/resistant hemagglutinatin and temperature-sensitive hemagglutinin. Among 243 isolates tested, 57.2 % (139), 28.8 % (70), 10.3 % (25) and 3.7 % (9) of the strains were shown resistant, intermediate resistant, low resistant and sensitive to SPF chicken sera, respectively. At 37℃, 64.6 % (157) of the strains showed mannose sensitive hemagglutination (MSHA) and 5.8 % (14) mannose resistant hemagglutination (MRHA) with chicken erythrocytes, while 74.9 % (182) of strains showed MSHA and 2.9% (7) MRHA with guinea pigs erythrocytes. However 46.1% (112) strains showed MRHA of chicken erythrocytes when cultured at 26℃. Of those with temperature-sensitive hemagglutinin (Tsh), 83 % to 100 % isolates belonged to the high pathogenic O1, O2 or O78 serogroups. The high prevalence of resistance to chicken sere, fimbriae F1, temperature-sensitive hemagglutinin in high pathogenic isolates suggested importance of these phenotypes in the pathogenesis of colibacillosis.