BACKGROUND:Enterotoxigenic E. coli (ETEC) significantly contribute to diarrhea in piglets and weaners. The smallholder pig producers in Uganda identified diarrhea as one of the major problems especially in piglets. The aim of this study was to; i) characterize the virulence factors of E. coli strains isolated from diarrheic and non-diarrheic suckling piglets and weaners from smallholder herds in northern and eastern Uganda and ii) identify and describe the post-mortem picture of ETEC infection in severely diarrheic piglets. Rectal swab samples were collected from 83 piglets and weaners in 20 herds and isolated E. coli were characterized by PCR, serotyping and hemolysis.
RESULTS:The E. coli strains carried genes for the heat stable toxins STa, STb and EAST1 and adhesins F4 and AIDA-I. The genes for the heat labile toxin LT and adhesins F5, F6, F18 and F41 were not detected in any of the E. coli isolates. Where the serogroup could be identified, E. coli isolates from the same diarrheic pig belonged to the same serogroup. The prevalence of EAST1, STb, Stx2e, STa, AIDA-I, and F4 in the E. coli isolates from suckling piglets and weaners (diarrheic and non-diarrheic combined) was 29, 26.5, 2.4, 1.2, 16, and 8.4 %, respectively. However the prevalence of F4 and AIDA-I in E. coli from diarrheic suckling piglets alone was 22.2 and 20 %, respectively. There was no significant difference in the prevalence of the individual virulence factors in E. coli from the diarrheic and non-diarrheic pigs (p > 0.05). The main ETEC strains isolated from diarrheic and non-diarrheic pigs included F4/STb/EAST1 (7.2 %), F4/STb (1.2 %), AIDA/STb/EAST1 (8 %) and AIDA/STb (8 %). At post-mortem, two diarrheic suckling piglets carrying ETEC showed intact intestinal villi, enterocytes and brush border but with a layer of cells attached to the brush border, suggestive of ETEC infections.
CONCLUSION:This study has shown that the F4 fimbriae is the most predominant in E. coli from diarrheic piglets in the study area and therefore an F4-based vaccine should be considered one of the preventive measures for controlling ETEC infections in the piglets in northern and eastern Uganda.
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【Prevalence of adhesin and toxin genes in E. coli strains isolated from diarrheic and non-diarrheic pigs from smallholder herds in northern and eastern Uganda.].
【从乌干达北部和东部小农户的腹泻猪和非腹泻猪分离的大肠杆菌菌株中黏附素和毒素基因的流行。】
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DOI：10.1186/s12866-016-0796-2文章类型：杂志文章
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背景：产肠毒素大肠埃希菌（ETEC）极大地促进了仔猪和断奶仔猪的腹泻。乌干达的小农户养猪者认为腹泻是主要问题之一，特别是在仔猪中。这项研究的目的是： i）表征从乌干达北部和东部的腹泻和非腹泻哺乳仔猪和断奶仔猪断奶的大肠杆菌菌株的毒力因子，并且ii）识别并描述严重腹泻仔猪ETEC感染的死后图像。从20个猪群的83头仔猪和断奶仔猪采集直肠拭子样品，并通过PCR，血清分型和溶血对分离的大肠杆菌进行表征。
结果：大肠杆菌菌株携带了热稳定毒素STa，STb和EAST1以及粘附素F4和AIDA-1的基因。在任何大肠杆菌分离物中均未检测到热不稳定毒素LT和粘附素F5，F6，F18和F41的基因。在可以鉴定血清群的地方，来自同一腹泻猪的大肠杆菌分离物属于同一血清群。 EAST1，STb，Stx2e，STa，AIDA-1和F4在来自乳猪和断奶仔猪（腹泻和非腹泻的组合）的大肠杆菌分离物中的患病率分别为29％，26.5％，2.4％，1.2％，16％和8.4％ ， 分别。然而，仅腹泻型乳猪在大肠杆菌中F4和AIDA-1的患病率分别为22.2％和20％。腹泻和非腹泻猪的大肠杆菌中单个毒力因子的患病率均无显着差异（p> 0.05）。从腹泻和非腹泻猪分离出的主要ETEC株包括F4 / STb / EAST1（7.2％），F4 / STb（1.2％），AIDA / STb / EAST1（8％）和AIDA / STb（8％）。验尸时，两只携带ETEC的腹泻乳猪表现出完整的肠绒毛，肠上皮细胞和刷状缘，但附着在刷状缘上有一层细胞，提示是ETEC感染。
结论：这项研究表明，F4菌毛是研究区域腹泻仔猪中大肠杆菌中最主要的菌种，因此基于F4的疫苗应被视为控制北部和南部仔猪ETEC感染的预防措施之一。乌干达东部。
结果：大肠杆菌菌株携带了热稳定毒素STa，STb和EAST1以及粘附素F4和AIDA-1的基因。在任何大肠杆菌分离物中均未检测到热不稳定毒素LT和粘附素F5，F6，F18和F41的基因。在可以鉴定血清群的地方，来自同一腹泻猪的大肠杆菌分离物属于同一血清群。 EAST1，STb，Stx2e，STa，AIDA-1和F4在来自乳猪和断奶仔猪（腹泻和非腹泻的组合）的大肠杆菌分离物中的患病率分别为29％，26.5％，2.4％，1.2％，16％和8.4％ ， 分别。然而，仅腹泻型乳猪在大肠杆菌中F4和AIDA-1的患病率分别为22.2％和20％。腹泻和非腹泻猪的大肠杆菌中单个毒力因子的患病率均无显着差异（p> 0.05）。从腹泻和非腹泻猪分离出的主要ETEC株包括F4 / STb / EAST1（7.2％），F4 / STb（1.2％），AIDA / STb / EAST1（8％）和AIDA / STb（8％）。验尸时，两只携带ETEC的腹泻乳猪表现出完整的肠绒毛，肠上皮细胞和刷状缘，但附着在刷状缘上有一层细胞，提示是ETEC感染。
结论：这项研究表明，F4菌毛是研究区域腹泻仔猪中大肠杆菌中最主要的菌种，因此基于F4的疫苗应被视为控制北部和南部仔猪ETEC感染的预防措施之一。乌干达东部。
