Spreads to the Large Intestine Lumen Via Multiple Pathways

in the genital tract is known to spread via the blood circulation system to the large intestine lumen to achieve long-lasting colonization. However, the precise pathways by which genital accesses the large intestine lumen remain unclear. The spleen was recently reported to be critical for chlamydial spreading. In the current study, it was found that following intravaginal inoculation with , mice with and without splenectomy both yielded infectious on rectal swabs, indicating that the spleen is not essential for genital to spread to the gastrointestinal tract. This conclusion was validated by the observation that intravenously inoculated was also detected on the rectal swabs of mice regardless of splenectomy. Careful comparison of the tissue distribution of live chlamydial organisms following intravenous inoculation revealed redundant pathways by which can reach the large intestine lumen. The intravenously inoculated was predominantly recruited to the spleen within 12 h and then detected in the stomach lumen by 24 h, in the intestinal lumen by 48 h, and on rectal swabs by 72 h. These observations suggest a potential spleen-to-stomach pathway for hematogenous to reach the large intestine lumen. This conclusion was supported by the observation made in mice under coprophagy-free condition. However, in the absence of spleen, hematogenous was predominantly recruited to the liver and then simultaneously detected in the intestinal tissue and lumen, suggesting a potential liver-to-intestine pathway for to reach the large intestine lumen. Thus, genital/hematogenous may reach the large intestine lumen via multiple redundant pathways.