Environmental Reservoirs of Non-tuberculous Mycobacteria in Cystic Fibrosis Households: A Case-control Study of Exposure Risk at Home (NTMecoCF)

This multicenter, non-interventional case-control study investigates whether household environmental reservoirs, particularly water systems, are associated with non-tuberculous mycobacterial (NTM) infections in people with cystic fibrosis. Environmental samples from the homes of CF patients with and without NTM infection will be analyzed and genetically compared with available clinical isolates, alongside assessment of environmental risk factors, to improve understanding of exposure pathways and inform future prevention strategies.

Study Overview

• Status: Recruiting
• Conditions: Cystic Fibrosis (CF); Non-Tuberculous Mycobacteria; Mycobacterium Abscessus Infection; Mucoviscidosis
• Intervention / Treatment: Other: Multi-modal NTM diagnostic including PCR, WGS, culture

Detailed Description

This multicenter, non-interventional case-control study investigates whether domestic environmental reservoirs-particularly household water systems-contribute to non-tuberculous mycobacterial (NTM) infections in people with cystic fibrosis (CF). Approximately 120 CF patients from several centers in Germany will be enrolled, including 60 patients with a current or previous pulmonary NTM infection and 60 CF patients without known NTM infection as controls.

Environmental samples (water, dust, and soil) will be collected from participants' households and analyzed for the presence of NTM using culture-based methods, PCR, and whole-genome sequencing. These findings will be compared between case and control households, and genetic similarity between environmental NTM isolates and available clinical isolates from the same patients will be assessed. In addition, standardized questionnaires will capture environmental and behavioral risk factors associated with NTM occurrence.

The study is purely observational and relies on clinical data and isolates obtained through routine CF care, with no additional medical procedures for participants. Over a follow-up period of up to three years, newly occurring NTM infections in initially unaffected patients will be documented. The results aim to improve understanding of environmental exposure risks for NTM in CF and to provide evidence for future prevention strategies and potential guideline recommendations.

• Study Type: Observational
• Enrollment (Estimated): 120

Contacts and Locations

• Study Contact: Name: Margo Diricks, PhD; Phone Number: +49 4537 / 188-7540; Email: mdiricks@fz-borstel.de
• Study Contact Backup: Name: Niklas Koehler, Dr. med.; Phone Number: +49 4537 188 8080; Email: studienzentrum@fz-borstel.de

Study Locations

• Germany
  • Essen, Germany
    • Not yet recruiting
    • Klinik für Pneumologie, Universitätsklinikum Essen
    • Contact: Sivagurunathan Sutharsan, PD Dr. med.; Phone Number: 0201 433-4001; Email: Sivagurunathan.Sutharsan@rlk.uk-essen.de
    • Principal Investigator: Sivagurunathan Sutharsan, PD Dr. med.
  • Schleswig-Holstein
    • Borstel, Schleswig-Holstein, Germany, 23845
      • Recruiting
      • National and WHO-Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center
      • Contact: Niklas Koehler, Dr. med.; Phone Number: +49 4537 188 8080; Email: studienzentrum@fz-borstel.de
      • Contact: Margo Dirics, PhD; Phone Number: +49 4537 / 188-7540; Email: mdiricks@fz-borstel.de
      • Principal Investigator: Alexander Mischnik, Prof. Dr. med.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population comprises 120 individuals with a confirmed diagnosis of cystic fibrosis recruited from multiple centers in Germany. Participants include both adults and minors (with consent from legal guardians) and are divided equally into a case group of patients with a current or prior pulmonary NTM infection and a control group of patients without a known history of NTM infection. All participants provide written informed consent, and clinical data and isolates are obtained exclusively from routine care.

Description

Inclusion Criteria:

• Confirmed diagnosis of cystic fibrosis (CF)
• No age restriction (including minors with consent from legal guardians)
• Written informed consent to participate in the study (or consent provided by a legal guardian for minors)
• In the case of an NTM infection: diagnosis according to ATS/IDSA criteria and availability of a clinical NTM isolate

Exclusion Criteria:

• Lack of capacity to provide informed consent, refusal to participate, or withdrawal of informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Case group; 60 CF patients with a confirmed current or previously diagnosed NTM infection (according to ATS/IDSA criteria)	Other: Multi-modal NTM diagnostic including PCR, WGS, culture; Environmental samples from participants' households (e.g., water, dust, and soil) will be collected and tested for the presence of NTM. Analyses will be performed using PCR, culture-based methods, whole-genome sequencing (WGS), and subsequent bioinformatic analyses. In addition, available clinical NTM isolates from previous or future routine diagnostics will be included. If genomic sequencing has not yet been performed for these isolates, retrospective molecular genetic analysis (e.g., by WGS) will be conducted within the study to enable comparison with environmental isolates.
Control group; 60 CF patients without a known or previously diagnosed NTM infection (according to ATS/IDSA criteria)	Other: Multi-modal NTM diagnostic including PCR, WGS, culture; Environmental samples from participants' households (e.g., water, dust, and soil) will be collected and tested for the presence of NTM. Analyses will be performed using PCR, culture-based methods, whole-genome sequencing (WGS), and subsequent bioinformatic analyses. In addition, available clinical NTM isolates from previous or future routine diagnostics will be included. If genomic sequencing has not yet been performed for these isolates, retrospective molecular genetic analysis (e.g., by WGS) will be conducted within the study to enable comparison with environmental isolates.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of NTM in environmental samples	Proportion of households of CF patients with and without NTM infection in which at least one (clinically relevant) NTM is detected in environmental samples (water, dust, soil).	2030
Difference in NTM prevalence between case and control groups	Statistically significant difference in the frequency of NTM detection (clinically relevant and/or all NTM) in environmental samples between case group and control group.	2030
Genetic concordance between environmental and patient isolates	Evidence of genetic relatedness (e.g., cgMLST clustering) between NTM detected in the household environment and clinical isolates from the same individual.	2030

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Characterization of NTM species from environmental samples	Identification and taxonomic classification of NTM isolates using WGS, including typing (e.g., subspecies assignment for M. avium).	2030
Identification of environmental and behavioral factors associated with NTM detection	Determination of significant risk factors (e.g., use of specific water sources, pet ownership, hygiene practices) based on questionnaire data and multivariable analyses.	2030
Long-term outcomes (control group only)	Proportion of patients without an initial NTM infection who develop a clinically relevant NTM infection during the follow-up period (up to 30 months), potentially in association with prior detection of NTM in the household environment.	2030

Collaborators and Investigators

• Sponsor: Research Center Borstel
• Investigators: Principal Investigator: Alexander Mischnik, Prof. Dr. med., National and WHO-Supranational Reference Center for Mycobacteria, Research Center Borstel, Leibniz Lung Center

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2030

Study Registration Dates

• First Submitted: January 16, 2026
• First Submitted That Met QC Criteria: January 16, 2026
• First Posted (Actual): January 27, 2026

Study Record Updates

• Last Update Posted (Actual): January 27, 2026
• Last Update Submitted That Met QC Criteria: January 16, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Environmental risk factors; Whole-genome sequencing; Microbial exposure; Environmental reservoirs; Household water systems
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Infections; Respiratory Tract Diseases; Digestive System Diseases; Lung Diseases; Infant, Newborn, Diseases; Pancreatic Diseases; Gram-Positive Bacterial Infections; Bacterial Infections; Bacterial Infections and Mycoses; Actinomycetales Infections; Mycobacterium Infections; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Cystic Fibrosis; Mycobacterium Infections, Nontuberculous; Investigative Techniques; Genetic Techniques; Sequence Analysis; Sequence Analysis, DNA; In Vitro Techniques; Culture Techniques; Whole Genome Sequencing
• Other Study ID Numbers: NTMecoCF

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD will be shared upon reasonable request via contacting the prinicpal investigator.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No