Human Infection with Chlamydia pneumoniae ST16 - Lishui City, Zhejiang Province, China, 2024.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Chlamydia pneumoniae (C. pneumoniae) is an important pathogen associated with respiratory infections. In China, C. pneumoniae pneumonia is not a notifiable infectious disease and is frequently overlooked in clinical detection protocols for community-acquired pneumonia. Consequently, the prevalence and genotypic distribution of chlamydial infections remain inadequately characterized.

WHAT IS ADDED BY THIS REPORT?: We investigated four patients with C. pneumoniae pneumonia in Lishui City, Zhejiang Province, China, between April and May 2024. All patients exhibited decreased levels of retinol-binding protein and prealbumin, with two patients presenting with co-infections. Analysis of the 16S rRNA and ompA gene sequences demonstrated 98% to 100% homology with known C. pneumoniae strains. To further characterize these isolates, we sequenced seven housekeeping genes, which revealed that all four patients were infected with the ST16 sequence type.

WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: Our findings underscore the necessity for enhanced surveillance and research on chlamydial infections, as well as the implementation of next-generation sequencing methodologies to improve pathogen identification, particularly in complex cases involving co-infections.