Chlamydiosis, an infection caused by several species, has been reported in Nile, saltwater, and Siamese crocodiles. Despite its widespread reports in various countries, including Thailand, genetic information on species remains limited. This study presents a whole-genome-based characterization of Siamese crocodile-isolated . The results showed that Siamese crocodile contained a single circular chromosome with a size of 1.22–1.23 Mbp and a plasmid with a size of 7.7–8.0 kbp. A plasmid containing eight coding sequences (CDSs) was grouped in a β lineage. A chromosome sequence had approximately 1,018–1,031 CDSs. Chlamydial factors involving virulence were documented in terms of the presence of cytotoxins and several virulence factors in the chromosomes of Siamese crocodile . The analysis of antimicrobial resistance genes in the genome revealed that the most common resistance genes were associated with aminoglycosides, fluoroquinolones, macrolides, tetracyclines, and cephalosporins, with loose matching (identities between 21.12 % and 74.65 %). Phylogenetic analyses, encompassing the assessments of both whole proteome and nine taxonomic markers, revealed that Siamese crocodile was separated into three lineages (lineages I–III) with high bootstrapping statistic support. Interestingly, isolate 12–01 differed genetically from the others, suggesting that it is a new member of . The study findings indicate that Siamese crocodiles are susceptible hosts to , involving more than one species. This study is the first employing the highest number of whole-genome data on Siamese crocodile and provides better insights into pathogen genetics.

中文翻译：

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暹罗鳄鱼（Crocodylus siamensis）分离衣原体的多样性和遗传特征

衣原体病是一种由多种物种引起的感染，已在尼罗河鳄鱼、咸水鳄鱼和暹罗鳄鱼中报告过。尽管在包括泰国在内的多个国家都有广泛报道，但有关物种的遗传信息仍然有限。这项研究提出了暹罗鳄鱼分离的基于全基因组的表征。结果显示，暹罗鳄含有一条大小为1.22-1.23 Mbp的环状染色体和一个大小为7.7-8.0 kbp的质粒。含有八个编码序列（CDS）的质粒被分为β谱系。一条染色体序列大约有 1,018–1,031 个 CDS。根据暹罗鳄鱼染色体中细胞毒素和几种毒力因子的存在，记录了涉及毒力的衣原体因子。对基因组中抗菌药物耐药基因的分析显示，最常见的耐药基因与氨基糖苷类、氟喹诺酮类、大环内酯类、四环素类和头孢菌素类相关，且匹配松散（同一性在21.12%至74.65%之间）。系统发育分析，包括对整个蛋白质组和九个分类标记的评估，显示暹罗鳄鱼被分为三个谱系（谱系 I-III），具有高度自举统计支持。有趣的是，分离株 12-01 在遗传上与其他分离株不同，表明它是 的新成员。研究结果表明，暹罗鳄鱼是该病毒的易感宿主，涉及多个物种。这项研究是首次采用最多数量的暹罗鳄鱼全基因组数据，并为病原体遗传学提供了更好的见解。