背景:影响仔猪新生儿腹泻发生的因素很多。目前,众所周知的病原体如产肠毒素大肠杆菌和C型产气荚膜梭菌似乎在疾病的发展中起次要作用。可能涉及其他感染性病原体。在这项研究中,我们的目的是调查有肠道疾病的临床和病理体征的新生仔猪中某些感染性病原体的存在。轮状病毒A,希雷肠球菌,在仔猪水平的病例对照研究中,研究了艰难梭菌和A/C型产气荚膜梭菌以及腹泻。在多步骤程序中,使用大肠杆菌分离株的群池来筛选它们的存在,研究了大肠杆菌毒力因子的可能作用。
结果:轮状病毒A在病例中的检出频率(25%)高于对照组(6%)(P<0.001)。肠球菌的检出率,艰难梭菌和A型产气荚膜梭菌β2基因阳性在两组仔猪中是相同的。研究中未检测到C型产气荚膜梭菌。对大肠杆菌毒力因子的调查显示,EAST1毒素基因(55%的测试案例仔猪为阳性)和AIDA-1粘附素基因(63%的毒素阳性案例仔猪为阳性)在案例仔猪中的患病率很高。
结论:轮状病毒A的检测与新生仔猪腹泻有统计学意义。携带毒力因子EAST1和AIDA-1的大肠杆菌的致病作用需要进一步研究,因为研究指出这两个因素是新生儿腹泻的可能致病因素。E.hirae的检测,携带β2基因的艰难梭菌和产气荚膜梭菌A型与新生仔猪腹泻无关。然而,该研究表明,在某些新生儿腹泻病例中,希拉大肠杆菌的大量过度生长可能是发病机理的一部分。
BACKGROUND: Many factors can influence the occurrence of neonatal diarrhoea in piglets. Currently, well-known pathogens such as enterotoxigenic Escherichia coli and Clostridium perfringens type C appear to play a minor role in development of disease. Other infectious pathogens may be involved. In this study, we aimed to investigate the presence of selected infectious pathogens in neonatal piglets with clinical and pathological signs of enteric disease. The association between rotavirus A, Enterococcus hirae, Clostridium difficile and Clostridium perfringens type A/C and diarrhoea was investigated in a case control study on piglet level. The possible role of E. coli virulence factors was investigated in a multistep-procedure using herd-pools of E.coli isolates to screen for their presence.
RESULTS: Rotavirus A was detected more often in cases (25%) than in controls (6%) (P < 0.001). The detection rate of Enterococcus hirae, Clostridium difficile and C. perfringens type A positive for beta2 genes was the same in the two groups of piglets. C. perfringens type C was not detected in the study. Investigations on E. coli virulence factors showed a high prevalence of EAST1 toxin genes (55% of tested case piglets were positive) and AIDA-1 adhesin genes (63% of toxin positive case piglets were positive) in case piglets.
CONCLUSIONS: Detection of rotavirus A was statistically significantly associated with neonatal piglet diarrhoea.An aetiologic role of E. coli carrying virulence factors EAST1 and AIDA-1 needs further investigation as the study points out these two factors as possible causative factors in neonatal diarrhoea.Detection of E.hirae, C.difficile and C. perfringens type A carrying beta 2 genes was not associated with neonatal piglet diarrhoea. However, the study suggested that massive overgrowth by E. hirae could be part of the pathogenesis in some cases of neonatal diarrhoea.