Notes from the Field: Hospital Water Contamination Associated with a Pseudo-Outbreak of Mycobacterium porcinum — Wisconsin, 2016–2018
Weekly / December 13, 2019 / 68(49);1149
Heather Kloth1; Lina I. Elbadawi, MD1,2; Allen Bateman, PhD3; Laura Louison, MLS3; Nijika Shrivastwa, PhD1 (View author affiliations)View suggested citation
Views equals page views plus PDF downloads
During January–December 2017, a hospital laboratory in Wisconsin identified a cluster of seven isolates that tested positive for a rapidly growing nontuberculous mycobacterium, Mycobacterium porcinum, which is associated with infections of the respiratory tract, bloodstream (caused by pathogen-contaminated intravenous catheters and equipment), surgical sites, and soft tissue (1–3). All clinical isolates were obtained from respiratory cultures (sputum, bronchoalveolar lavages, or bronchial aspirates) from patients in the hospital’s intensive care units. No associated clinical infections were reported. Because M. porcinum is rarely encountered, a concern that these isolates represented laboratory contamination was raised, and the hospital infection prevention team began an internal investigation. During this time, the hospital’s infection prevention team and the Wisconsin State Laboratory of Hygiene (WSLH) investigated possible infection control breaches and laboratory workflow processes. Following the identification of four additional isolates in January 2018, all patient specimens submitted for acid-fast bacteria culture were routed directly to WSLH for testing beginning February 12. WSLH identified three additional positive M. porcinum isolates from patients, suggesting that the organism was not a hospital laboratory contaminant. On March 16, the hospital notified the Wisconsin Division of Public Health of the cluster of M. porcinum–positive respiratory isolates. By April 12, a total of 20 isolates had been obtained from 16 patients. A retrospective chart review demonstrated that none of the isolates were associated with a clinical infection; other infections accounted for all patients’ illnesses.
Because nontuberculous mycobacteria are found in water, and M. porcinum in particular has been recovered from tap water (1), the investigation included testing water samples from the ice machines, water dispensers, and handwashing sinks in the intensive care units collected during the week of April 23. M. porcinum was subsequently identified during April 30–May 3 in samples obtained from two ice machines and one water dispenser. Inspection of these machines demonstrated visible debris on internal machine parts and dispenser spouts. Since the installation of new machines and parts in June 2018 and revision of the hospital’s cleaning protocols, no further M. porcinum patient isolates have been identified. In accordance with a recommendation from the Wisconsin Division of Public Health, staff members at this hospital no longer use tap water when collecting respiratory cultures.
M. porcinum is a rapidly growing nontuberculous mycobacterium within the Mycobacterium fortuitum complex. Nontuberculous mycobacteria naturally occur in the environment and can be found in soil and water, including potable water systems that supply many U.S. health care facilities (4). Nontuberculous mycobacteria have also been associated with outbreaks in health care settings (1–4). Tap water was used during respiratory specimen collection at the Wisconsin facility and might have contaminated patient specimens. Tap water is not sterile, can lead to false-positive culture results (4), and should be avoided when collecting biologic specimens intended for culture. Hospital water management programs should engage clinical partners to ensure safe water use as part of patient care and address maintenance of ice machines and water dispensers within their facilities.
Corresponding author: Lina I. Elbadawi, email@example.com, 404-718-3619.
1Bureau of Communicable Diseases, Wisconsin Division of Public Health; 2Center for Preparedness and Response, CDC; 3Wisconsin State Laboratory of Hygiene.
All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed.
- Brown-Elliott BA, Wallace RJ, Tichindelean C, et al. Five-year outbreak of community- and hospital-acquired Mycobacterium porcinum related to public water supplies. J Clin Microbiol 2011;49:4231–8. CrossRefexternal icon PubMedexternal icon
- Crist MB, Perz JF. Modern healthcare versus nontuberculous mycobacteria: who will have the upper hand? Clin Infect Dis 2017;64:912–3. PubMedexternal icon
- Halstrom S, Price P, Thomson R. Review: environmental mycobacteria as a cause of human infection. Int J Mycobacteriol 2015;4:81–91. CrossRefexternal icon PubMedexternal icon
- LaBombardi VJ, O’Brien AM, Kislak JW. Pseudo-outbreak of Mycobacterium fortuitum due to contaminated ice machines. Am J Infect Control 2002;30:184–6. CrossRefexternal icon PubMedexternal icon
Suggested citation for this article: Kloth H, Elbadawi LI, Bateman A, Louison L, Shrivastwa N. Notes from the Field: Hospital Water Contamination Associated with a Pseudo-Outbreak of Mycobacterium porcinum — Wisconsin, 2016–2018. MMWR Morb Mortal Wkly Rep 2019;68:1149. DOI: http://dx.doi.org/10.15585/mmwr.mm6849a4external icon.
MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of Health and Human Services.
References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the U.S. Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication.
All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr) and/or the original MMWR paper copy for printable versions of official text, figures, and tables.
Questions or messages regarding errors in formatting should be addressed to firstname.lastname@example.org.