Longitudinal and Cross-sectional Analysis of Pulmonary Microbiota in Lung Transplant Recipients Infected With Nocardia

Completed

• Conditions: Nocardia Infections; Lung Transplantation
• Interventions: Drug: Antibiotic Treatment

• Registration Number: NCT06594133
• Lead Sponsor: Zhibin Xu

Brief Summary

This retrospective observational study aims to explore the impact of Nocardia infection on the pulmonary microbiota of lung transplant recipients (LTRs). The study will analyze both cross-sectional and longitudinal data from patients diagnosed with Nocardia pneumonia, comparing microbial composition and diversity between infected and non-infected groups. This research seeks to provide insights into the relationship between pulmonary microbiota alterations and clinical outcomes in LTRs.

Detailed Description

This study is a single-center, retrospective, observational study designed to investigate the impact of Nocardia infection on the pulmonary microbiota of lung transplant recipients (LTRs). The study will include both cross-sectional and longitudinal analyses. In the cross-sectional study, 17 LTRs diagnosed with Nocardia pneumonia (Nocardia pneumonia group, NPG) will be compared with 51 non-infected LTRs (non-Nocardia infection group, NNIG) matched for age, sex, and underlying conditions.

The longitudinal study will follow LTRs over a 4-month period, collecting samples before, during, and after treatment. Patients in this group will be categorized into the Recovered group (RG) or Not Recovered group (NRG) based on treatment outcomes. The study will also include a subgroup analysis of patients with disseminated Nocardia infection, comparing pulmonary and systemic microbiota changes.

Microbial diversity and composition will be assessed using high-throughput sequencing of bronchoalveolar lavage fluid (BALF) samples. Statistical analyses will include the Kolmogorov-Smirnov test, ANOVA, and Kruskal-Wallis test for group comparisons, with linear mixed-effects models used to analyze changes over time.

The goal of this study is to provide a deeper understanding of how Nocardia infection affects the pulmonary microbiota in LTRs and to identify key microbial species associated with clinical outcomes.

Study Timeline

• Study Start: 2023-01-01
• Primary Completion: 2024-08-01
• Study Completion: 2024-09-01
• Study First Submitted: 2024-09-10
• Study First Submitted QC: 2024-09-10
• Study First Posted: 2024-09-19
• Status Verified: 2024-11
• Last Update Submitted: 2024-11-11
• Last Update Posted: 2024-11-12

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 68

Inclusion Criteria

• Lung transplant recipients
• Diagnosed with Nocardia pneumonia (for the study group)
• Age ≥ 18 years

Exclusion Criteria

• Patients with incomplete medical records
• Patients who survived ≤ 3 days after transplantation
• Patients lost to follow-up

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Nocardia Pneumonia Group (NPG)	Antibiotic Treatment	This group consists of lung transplant recipients diagnosed with Nocardia pneumonia. The patients in this group are studied to assess the impact of Nocardia infection on the pulmonary microbiota. Samples including bronchoalveolar lavage fluid (BALF) and blood are collected for microbial community analysis.

Primary Outcome Measures

Name	Time	Method
Pulmonary Microbiota Diversity in Nocardia-infected Lung Transplant Recipients	January 2023 to August 2024	Measurement of alpha and beta diversity of the pulmonary microbiota in BALF samples from lung transplant recipients with and without Nocardia infection. Alpha diversity will be quantified using Shannon diversity index and observed species richness, while beta diversity will be analyzed using Bray-Curtis dissimilarity. Microbial composition and relative abundance will be compared between the Nocardia pneumonia group and the non-Nocardia infection group. Changes in diversity metrics will be analyzed over time to assess the impact of Nocardia infection on pulmonary microbiota.

Secondary Outcome Measures

Name	Time	Method
Correlation Between Pulmonary Microbiota and Clinical Outcomes	January 2023 to August 2024	Correlation between pulmonary microbiota diversity and clinical factors such as age, kidney function, nutritional status, and immunosuppressive therapy in lung transplant recipients. The analysis includes changes in pulmonary microbiota before and after treatment in patients with Nocardia infection and the number of participants showing significant correlations between microbiota diversity and clinical outcomes.

Trial Locations

Locations (1)

Guangzhou Institute of Respiratory Diseases, the First Affiliated Hospital of Guangzhou Medical University; 🇨🇳 Guangzhou, Guangdong, China