Ehrlichia canis is the etiologic agent of a highly prevalent tick-borne disease, canine monocytic ehrlichiosis (CME). Four defined E. canis genotypes based on the trp36 gene sequences have been reported, three of them identified in North or South America. The diversity of E. canis has been investigated using genetic and serologic approaches based on distinct 36 kDa tandem repeat protein (trp36) gene sequences that have been reported. The main objectives of this study were to determine the prevalence of E. canis infection in dogs from Medellín, Colombia by PCR and determine the E. canis diversity using molecular and serologic approaches. Blood was collected from dogs (n = 300) with clinical signs of CME for PCR detection of E. canis 16S rRNA, dsb and trp36 DNA. Phylogenetic analysis of trp36 gene sequences was performed using MEGA. A serological evaluation was performed using immunofluorescence microscopy and ELISA with species-specific peptides from E. canis TRP19 and TRP36 (3 genotypes) and E. chaffeensis (TRP32). E. canis DNA (16S rRNA and/or dsb) was detected in 18 % (53/300) of dogs by PCR amplification. The trp36 gene was amplified and sequenced from 35/53 16S rRNA/dsb PCR positive samples revealing three genotypes: United States (US; n = 21), Costa Rica (CR; n = 11), and Brazil (BR; n = 3). Most dogs (33/35) with detectable trp36 DNA had anti-E. canis TRP19 and TRP36 peptide antibodies that corresponded to the genotype detected by PCR. Dogs that had antibodies to the TRP19 peptide (82/300; 38 %), also had antibodies to one or more genotype-specific TRP36 peptides. Based on TRP36 serology, the dogs exhibited highest frequency of infection with the US genogroup (US = 26), followed by the CR genogroup (CR = 19) and the BR genogroup (BR = 11). Notably, 26/53 trp36 PCR positive dogs had detectable antibodies to multiple E. canis genotypes (US/BR/CR = 8, BR/CR = 7, US/CR = 6 and US/BR = 5) suggesting coinfection or multiple sequential infections with different genotypes. Colombian dogs did not have antibodies to E. chaffeensis as determined by a TRP32 species-specific ELISA. Our results demonstrate the presence of three previously defined genotypes in North and South America in Colombian dogs (US, BR, CR). These results also demonstrate that TRP19 and TRP36 serology can provide valuable information regarding E. canis exposure and the potential genotype(s) involved in infection.

犬埃里希氏菌是一种高度流行的壁虱传播疾病犬单核细胞埃希氏菌病（CME）的病原体。已经报道了基于trp36基因序列的四种确定的犬大肠杆菌基因型，其中三种在北美或南美被鉴定。基于已报道的独特的36 kDa串联重复蛋白（trp36）基因序列，已使用遗传和血清学方法研究了犬大肠杆菌的多样性。这项研究的主要目的是通过PCR确定来自哥伦比亚麦德林的犬中的犬大肠杆菌感染率，并确定犬大肠杆菌使用分子和血清学方法的多样性。从具有CME临床体征的犬（n = 300）中采集血液，用于PCR检测犬大肠杆菌16S rRNA ，dsb和trp36 DNA。使用MEGA进行了trp36基因序列的系统发育分析。使用免疫荧光显微镜和ELISA与物种特异性的肽从进行血清学评价犬埃里希氏体TRP19和TRP36（3个基因型）和恰菲埃里希氏体（TRP32）。犬埃里希氏体DNA（的16S rRNA和/或DSB）在狗中通过PCR扩增的18％（300分之53）检测。的trp启动36基因扩增并从53分之35的16S rRNA /测序DSBPCR阳性样品揭示了三种基因型：美国（US； n = 21），哥斯达黎加（CR； n = 11）和巴西（BR； n = 3）。大多数具有可检测到的trp 36 DNA的狗（33/35）都具有犬埃里希氏菌TRP19和TRP36肽抗体，对应于PCR检测到的基因型。含有抗TRP19肽抗体的狗（82/300； 38％）也具有抗一种或多种基因型特异性TRP36肽的抗体。根据TRP36血清学，这些犬表现出US基因组（US = 26）的最高感染频率，其次是CR基因组（CR = 19）和BR基因组（BR = 11）。值得注意的是，26/53 trp36 PCR阳性狗具有可检测到的针对多种犬大肠杆菌的抗体基因型（US / BR / CR = 8，BR / CR = 7，US / CR = 6和US / BR = 5），提示合并感染或具有不同基因型的多次连续感染。如TRP32物种特异性ELISA所确定，哥伦比亚狗不具有对恰菲大肠杆菌的抗体。我们的结果表明，在北美和南美的哥伦比亚犬中存在三种先前定义的基因型（US，BR，CR）。这些结果还表明，TRP19和TRP36血清学可以提供有关犬大肠杆菌暴露和感染涉及的潜在基因型的有价值的信息。