Molecular detection of chlamydiales in captive zoo animals at Songkhla Zoo, southern Thailand

Abstract

Several species of Chlamydia are recognized as significant zoonotic pathogens that infect a wide range of hosts, including humans. This study aimed to investigate the occurrence and genetic characteristics of Chlamydiales–related bacteria in captive animals at Songkhla Zoo, southern Thailand. A total of 92 cloacal and rectal swab samples were collected from mammals (n = 22), birds (n = 55), and reptiles (n = 15). Genomic DNA was screened using polymerase chain reaction (PCR) targeting the Chlamydiales 16S rRNA gene and the ompA gene specific for Chlamydia psittaci. Positive amplicons were subjected to Sanger sequencing and phylogenetic analysis. A single sample obtained from an asymptomatic giant Asian pond turtle (Heosemys grandis) tested positive for the Chlamydiales 16S rRNA gene, resulting in a detection rate of 1.09% (95% CI: 0.03–5.91%). Sequence analysis revealed 100% nucleotide identity to the previously reported Chlamydiales bacterium AY845420.1 and divergence from recognized pathogenic species. This study provides preliminary molecular evidence of Chlamydiales–related DNA in a captive giant Asian pond turtle in Thailand and supports the need for continued surveillance in zoological collections.