Epidemiological and clinical characteristics of psittacosis among cases with complicated or atypical pulmonary infection using metagenomic next-generation sequencing: a multi-center observational study in China

A case of severe psittacosis pneumonia complicated by splenic infarction

CLINICAL DATA

Chlamydia psittaci pneumonia is a community-acquired pneumonia caused by Chlamydia psittaci. While severe cases may lead to critical conditions such as respiratory failure, splenic infarction is relatively uncommon. A severe patient with Chlamydia psittaci pneumonia admitted to our hospital experienced a splenic infarction during treatment. Fortunately, the patient's situation was improved after careful treatment. Now, the patient has been discharged. Further exploration of the mechanism of concurrent splenic infarction is required.

BACKGROUD

Psittacosis pneumonia, a zoonotic infectious disease transmitted from birds to humans, is caused by Chlamydia psittaci and represents a type of chlamydial pneumonia [1]. Insome instances, the disease may progress to severe pneumonia and respiratory failure, necessitating intensive support measures, including mechanical ventilation. The advent of technologies such as Metagenomic Next-Generation Sequencing (mNGS) for the etiological diagnosis of infectious diseases [2] has improved the diagnostic and treatment success rates for Psittacosis. Instances of severe chlamydial pneumonia with complications such as splenic infarction are uncommon. A patient with severe Psittacosis pneumonia complicated by splenic infarction was admitted to the Emergency Intensive Care Unit (EICU) of Haining People's Hospital and subsequently improved following effective anti-infective and anticoagulant therapy. This report is provided herein.

Case Report: Pneumonia Caused by Chlamydia Psittaci and Cryptococcus Co-Infection

This study presents a rare case of pneumonia caused by a co-infection of Chlamydia psittaci and Cryptococcus, confirmed by metagenomic next-generation sequencing (mNGS). The patient, who had underlying chronic hepatitis B, had adopted a stray pigeon before the onset of the disease. The primary symptoms were fever, and a productive cough. The patient recovered following treatment with moxifloxacin and itraconazole. C. psittaci and Cryptococcus infections may both have been transmitted from the stray pigeon. This report highlights the potential for infections caused by multiple zoonotic pathogens and the value of mNGS for making the diagnosis of these infections.

The serodiagnositic value of Chlamydia trachomatis antigens in antibody detection using luciferase immunosorbent assay

Introduction

Among the different antigens used in the detection of anti-Chlamydia trachomatis antibodies, significant differences in sensitivity and specificity have been observed. Further evaluation of C. trachomatis antigens in antibody detection is urgently needed for the development and application of C. trachomatis serologic assays.

Methods

Chlamydia trachomatis antigens Pgp3, TmeA, InaC, and HSP60 were selected and used in luciferase immunosorbent assay (LISA). The detection results obtained from well-defined C. trachomatis positive and negative samples were compared with the commercial C. trachomatis ELISA (Mikrogen) for performance evaluation.

Results

Pgp3, TmeA, InaC, and HSP60-based LISA showed sensitivity of 92.8, 88.8, 90.4, and 94.4%, and specificity of 99.2, 99.2, 99.2, and 92%, respectively. ROC analysis indicated that Pgp3-based LISA showed similar performance to Mikrogen ELISA (AUC 0.986 vs. 0.993, p = 0.207). Furthermore, four C. trachomatis antigens achieved strong diagnostic efficiency, i.e., positive likelihood ratios [+LR] ≥ 10 in C. trachomatis-infected women and negative likelihood ratios [-LR] ≤ 0.1 in C. trachomatis negative low exposure risk children, but only Pgp3 and TmeA showed strong diagnostic value in general adults. In addition, Pgp3, TmeA, and InaC, but not HSP60, achieved high performance, i.e., both positive predictive value (PPV) and negative predictive value (NPV) ≥ 90.9%, and showed no significant cross-reactivity with anti-Chlamydiapneumoniae.

Conclusion

Three C. trachomatis species-specific antigens Pgp3, TmeA, and InaC show superior performance in the detection of anti-C. trachomatis antibody, indicating the potential to be used in developing C. trachomatis serologic tests.