Gina Oda1, Mark A Winters2,3, Susan M Pacheco4,5, Monica K Sikka6,7, Susan C Bleasdale6,7, Bruce Dunn8,9, Erin Boswell10,11, Benjamin Winters2, Amelia Bumsted4, Jennifer Frisch10, Mark Holodniy1,2,3. 1. Public Health Surveillance and Research, Department of Veterans Affairs, Palo Alto, California. 2. VHA Public Health Reference Laboratory, Palo Alto, California. 3. Division of Infectious Disease & Geographic Medicine, Stanford University School of Medicine, Stanford, California. 4. Edward Hines Jr. VA Medical Center, Chicago, Illinois. 5. Loyola University Medical Center, Maywood, Illinois. 6. Jesse Brown VA Medical Center, Chicago, Illinois. 7. University of Illinois, Chicago, Illinois. 8. Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin. 9. Medical College of Wisconsin, Milwaukee, Wisconsin. 10. Southeast Louisiana Veterans Health Care System, New Orleans, Louisiana. 11. Tulane University School of Medicine, New Orleans, Louisiana.
Abstract
OBJECTIVE: To characterize nontuberculous mycobacteria (NTM) associated with case clusters at 3 medical facilities. DESIGN: Retrospective cohort study using molecular typing of patient and water isolates. SETTING: Veterans Affairs Medical Centers (VAMCs). METHODS: Isolation and identification of NTM from clinical and water samples using culture, MALDI-TOF, and gene population sequencing to determine species and genetic relatedness. Clinical data were abstracted from electronic health records. RESULTS: An identical strain of Mycobacterium conceptionense was isolated from 41 patients at VA Medical Centers (VAMCs A, B, and D), and from VAMC A's ICU ice machine. Isolates were initially identified as other NTM species within the M. fortuitum clade. Sequencing analyses revealed that they were identical M. conceptionense strains. Overall, 7 patients (17%) met the criteria for pulmonary or nonpulmonary infection with NTM, and 13 of 41 (32%) were treated with effective antimicrobials regardless of infection or colonization status. Separately, a M. mucogenicum patient strain from VAMC A matched a strain isolated from a VAMC B ICU ice machine. VAMC C, in a different state, had a 4-patient cluster with Mycobacterium porcinum. Strains were identical to those isolated from sink-water samples at this facility. CONCLUSION: NTM from hospital water systems are found in hospitalized patients, often during workup for other infections, making attribution of NTM infection problematic. Variable NTM identification methods and changing taxonomy create challenges for epidemiologic investigation and linkage to environmental sources.
OBJECTIVE: To characterize nontuberculous mycobacteria (NTM) associated with case clusters at 3 medical facilities. DESIGN: Retrospective cohort study using molecular typing of patient and water isolates. SETTING: Veterans Affairs Medical Centers (VAMCs). METHODS: Isolation and identification of NTM from clinical and water samples using culture, MALDI-TOF, and gene population sequencing to determine species and genetic relatedness. Clinical data were abstracted from electronic health records. RESULTS: An identical strain of Mycobacterium conceptionense was isolated from 41 patients at VA Medical Centers (VAMCs A, B, and D), and from VAMC A's ICU ice machine. Isolates were initially identified as other NTM species within the M. fortuitum clade. Sequencing analyses revealed that they were identical M. conceptionense strains. Overall, 7 patients (17%) met the criteria for pulmonary or nonpulmonary infection with NTM, and 13 of 41 (32%) were treated with effective antimicrobials regardless of infection or colonization status. Separately, a M. mucogenicumpatient strain from VAMC A matched a strain isolated from a VAMC B ICU ice machine. VAMC C, in a different state, had a 4-patient cluster with Mycobacterium porcinum. Strains were identical to those isolated from sink-water samples at this facility. CONCLUSION:NTM from hospital water systems are found in hospitalized patients, often during workup for other infections, making attribution of NTMinfection problematic. Variable NTM identification methods and changing taxonomy create challenges for epidemiologic investigation and linkage to environmental sources.