Blanco Miguel, Lazo Leonel, Blanco Jesús E, Dahbi Ghizlane, Mora Azucena, López Cecilia, González Enrique A, Blanco Jorge
E. coli Reference Laboratory, Department of Microbiology and Parasitology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
Int Microbiol. 2006 Mar;9(1):53-60.
Thirty-six enteropathogenic Escherichia coli strains isolated from Cuban pigs with diarrhea were serotyped and screened by PCR for the presence of virulence genes. The 36 isolates belonged to 11 O serogroups and 14 O:H serotypes, with 53% of the isolates belonging to only two serotypes: O141:H- (13 isolates) and O157:H19 (6 isolates). Genes coding for STb, STa, VT2e, and LT toxins were identified in 69, 61, 53, and 6% of the isolates, respectively. The most prevalent fimbrial adhesin was F18, detected in 22 (61%) isolates. The gene encoding F6 (P987) colonization factor was identified in three (8%) isolates. None of the 36 isolates assayed contained genes encoding F4 (K88), F5 (K99), or F41. The seropathotype O141:H-:STa/STb/VT2e/F18 (13 isolates) was the most frequently detected, followed by O157:H19:VT2e/F18 (5 isolates). A genetic diversity study, carried out by pulsed-field gel electrophoresis (PFGE) of 24 representative isolates, revealed 21 distinct restriction patterns clustered in 18 groups (I-XVIII). Isolates of the same serotype were placed together in a dendrogram, but isolates of serotype O157:H19 showed a high degree of polymorphism. The results of this study demonstrate the presence in Cuba of different clusters among one of the most prevalent serotypes isolated from pigs with diarrhea. Further experiments are needed to determine whether some of these clusters have appeared recently; if so, their evolution, as well as their possible association with pathogenicity in farms should be studied.
从患有腹泻的古巴猪中分离出36株肠致病性大肠杆菌菌株，对其进行血清分型，并通过PCR检测毒力基因的存在情况。这36株分离株属于11个O血清群和14个O:H血清型，其中53%的分离株仅属于两种血清型：O141:H-（13株）和O157:H19（6株）。分别在69%、61%、53%和6%的分离株中鉴定出编码STb、STa、VT2e和LT毒素的基因。最常见的菌毛黏附素是F18，在22株（61%）分离株中检测到。在3株（8%）分离株中鉴定出编码F6（P987）定植因子的基因。所检测的36株分离株中均未含有编码F4（K88）、F5（K99）或F41的基因。血清致病型O141:H-:STa/STb/VT2e/F18（13株）是最常检测到的，其次是O157:H19:VT2e/F18（5株）。通过对24株代表性分离株进行脉冲场凝胶电泳（PFGE）开展的遗传多样性研究显示，21种不同的限制性酶切图谱聚为18组（I - XVIII）。同一血清型的分离株在聚类图中归为一类，但血清型O157:H19的分离株显示出高度多态性。本研究结果表明，在古巴，从腹泻猪中分离出的最常见血清型之一存在不同的聚类群。需要进一步实验来确定这些聚类群中是否有一些是最近出现的；如果是这样，应研究它们的进化以及它们与猪场致病性的可能关联。
