Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery

Abstract. The expanding application of targeted next-generation sequencing (tNGS) in clinical diagnostics has led to an increasing frequency of Nocardia spp. detection in respiratory specimens; however, the clinical relevance and interpretation of these findings remain uncertain. This study describe...

Full description

Saved in:
Bibliographic Details
Main Authors: Chaowen Deng, Simon Kam-Fai Lo, Kelvin Hei-Yeung Chiu, Fanfan Xing
Format: Article
Language:English
Published: Wolters Kluwer Health 2025-06-01
Series:Infectious Microbes & Diseases
Online Access:http://journals.lww.com/10.1097/IM9.0000000000000179
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849416654948139008
author Chaowen Deng
Simon Kam-Fai Lo
Kelvin Hei-Yeung Chiu
Fanfan Xing
author_facet Chaowen Deng
Simon Kam-Fai Lo
Kelvin Hei-Yeung Chiu
Fanfan Xing
author_sort Chaowen Deng
collection DOAJ
description Abstract. The expanding application of targeted next-generation sequencing (tNGS) in clinical diagnostics has led to an increasing frequency of Nocardia spp. detection in respiratory specimens; however, the clinical relevance and interpretation of these findings remain uncertain. This study describes the epidemiology of Nocardia pneumonia and colonization in patients at The University of Hong Kong–Shenzhen Hospital, China, and evaluates the diagnostic role of tNGS. The analysis was conducted from January 2023 through December 2024 and included 22 patients in whom Nocardia spp. were detected in respiratory specimens via tNGS. Among these patients, 81.8% (18/22) had comorbidities, most commonly chronic lung disease (40.9%, 9/22). Common clinical symptoms included cough, sputum and fever. Nocardia farcinica and Nocardia abscessus were the predominant species identified. Although the median number of sequence reads of Nocardia were higher in infected patients than in colonized individuals (289, IQR: 132.5–3747 vs. 133.5, IQR: 51.75–261.3), the difference was not statistically significant (P >0.05). In a comparison of diagnostic performance, tNGS identified Nocardia sequences in all 25 respiratory samples collected from the enrolled patients, whereas conventional aerobic culture successfully isolated the pathogen in only two patients. Additionally, tNGS exhibited a significantly shorter median turnaround time than culture (38 h vs. 376.5 h). These findings highlight tNGS as a rapid tool for Nocardia detection. However, the final diagnosis of nocardiosis cannot rely solely on sequence read thresholds. Clinical, radiological and laboratory integration remains critical in distinguishing true infection from colonization, ensuring accurate diagnosis and management of nocardiosis.
format Article
id doaj-art-64211c91dbbc4e0b86dcb0f1a9423073
institution Kabale University
issn 2641-5917
language English
publishDate 2025-06-01
publisher Wolters Kluwer Health
record_format Article
series Infectious Microbes & Diseases
spelling doaj-art-64211c91dbbc4e0b86dcb0f1a94230732025-08-20T03:33:07ZengWolters Kluwer HealthInfectious Microbes & Diseases2641-59172025-06-017210111010.1097/IM9.0000000000000179202506000-00005Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely DiscoveryChaowen Deng0Simon Kam-Fai Lo1Kelvin Hei-Yeung Chiu2Fanfan Xing3Author affiliations: 1 Department of Infectious Diseases and Microbiology, The University of Hong Kong–Shenzhen Hospital, Shenzhen, ChinaAuthor affiliations: 1 Department of Infectious Diseases and Microbiology, The University of Hong Kong–Shenzhen Hospital, Shenzhen, China2 Department of Microbiology, Queen Mary Hospital, Hong Kong SAR, China.Author affiliations: 1 Department of Infectious Diseases and Microbiology, The University of Hong Kong–Shenzhen Hospital, Shenzhen, ChinaAbstract. The expanding application of targeted next-generation sequencing (tNGS) in clinical diagnostics has led to an increasing frequency of Nocardia spp. detection in respiratory specimens; however, the clinical relevance and interpretation of these findings remain uncertain. This study describes the epidemiology of Nocardia pneumonia and colonization in patients at The University of Hong Kong–Shenzhen Hospital, China, and evaluates the diagnostic role of tNGS. The analysis was conducted from January 2023 through December 2024 and included 22 patients in whom Nocardia spp. were detected in respiratory specimens via tNGS. Among these patients, 81.8% (18/22) had comorbidities, most commonly chronic lung disease (40.9%, 9/22). Common clinical symptoms included cough, sputum and fever. Nocardia farcinica and Nocardia abscessus were the predominant species identified. Although the median number of sequence reads of Nocardia were higher in infected patients than in colonized individuals (289, IQR: 132.5–3747 vs. 133.5, IQR: 51.75–261.3), the difference was not statistically significant (P >0.05). In a comparison of diagnostic performance, tNGS identified Nocardia sequences in all 25 respiratory samples collected from the enrolled patients, whereas conventional aerobic culture successfully isolated the pathogen in only two patients. Additionally, tNGS exhibited a significantly shorter median turnaround time than culture (38 h vs. 376.5 h). These findings highlight tNGS as a rapid tool for Nocardia detection. However, the final diagnosis of nocardiosis cannot rely solely on sequence read thresholds. Clinical, radiological and laboratory integration remains critical in distinguishing true infection from colonization, ensuring accurate diagnosis and management of nocardiosis.http://journals.lww.com/10.1097/IM9.0000000000000179
spellingShingle Chaowen Deng
Simon Kam-Fai Lo
Kelvin Hei-Yeung Chiu
Fanfan Xing
Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
Infectious Microbes & Diseases
title Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
title_full Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
title_fullStr Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
title_full_unstemmed Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
title_short Nocardia Detection in Respiratory Samples Using Targeted Next-Generation Sequencing: Cautious Interpretation Is Necessary for Timely Discovery
title_sort nocardia detection in respiratory samples using targeted next generation sequencing cautious interpretation is necessary for timely discovery
url http://journals.lww.com/10.1097/IM9.0000000000000179
work_keys_str_mv AT chaowendeng nocardiadetectioninrespiratorysamplesusingtargetednextgenerationsequencingcautiousinterpretationisnecessaryfortimelydiscovery
AT simonkamfailo nocardiadetectioninrespiratorysamplesusingtargetednextgenerationsequencingcautiousinterpretationisnecessaryfortimelydiscovery
AT kelvinheiyeungchiu nocardiadetectioninrespiratorysamplesusingtargetednextgenerationsequencingcautiousinterpretationisnecessaryfortimelydiscovery
AT fanfanxing nocardiadetectioninrespiratorysamplesusingtargetednextgenerationsequencingcautiousinterpretationisnecessaryfortimelydiscovery