Dataset Information

Two-Phase Hospital-Associated Outbreak of Mycobacterium abscessus: Investigation and Mitigation.

ABSTRACT:

Background

Nontuberculous mycobacteria (NTM) commonly colonize municipal water supplies and cause healthcare-associated outbreaks. We investigated a biphasic outbreak of Mycobacterium abscessus at a tertiary care hospital.

Methods

Case patients had recent hospital exposure and laboratory-confirmed colonization or infection with M. abscessus from January 2013 through December 2015. We conducted a multidisciplinary epidemiologic, field, and laboratory investigation.

Results

The incidence rate of M. abscessus increased from 0.7 cases per 10000 patient-days during the baseline period (January 2013-July 2013) to 3.0 cases per 10000 patient-days during phase 1 of the outbreak (August 2013-May 2014) (incidence rate ratio, 4.6 [95% confidence interval, 2.3-8.8]; P < .001). Thirty-six of 71 (51%) phase 1 cases were lung transplant patients with positive respiratory cultures. We eliminated tap water exposure to the aerodigestive tract among high-risk patients, and the incidence rate decreased to baseline. Twelve of 24 (50%) phase 2 (December 2014-June 2015) cases occurred in cardiac surgery patients with invasive infections. Phase 2 resolved after we implemented an intensified disinfection protocol and used sterile water for heater-cooler units of cardiopulmonary bypass machines. Molecular fingerprinting of clinical isolates identified 2 clonal strains of M. abscessus; 1 clone was isolated from water sources at a new hospital addition. We made several water engineering interventions to improve water flow and increase disinfectant levels.

Conclusions

We investigated and mitigated a 2-phase clonal outbreak of M. abscessus linked to hospital tap water. Healthcare facilities with endemic NTM should consider similar tap water avoidance and engineering strategies to decrease risk of NTM infection.

SUBMITTER: Baker AW

PROVIDER: S-EPMC5848312 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

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Publications

Two-Phase Hospital-Associated Outbreak of Mycobacterium abscessus: Investigation and Mitigation.

Baker Arthur W AW Lewis Sarah S SS Alexander Barbara D BD Chen Luke F LF Wallace Richard J RJ Brown-Elliott Barbara A BA Isaacs Pamela J PJ Pickett Lisa C LC Patel Chetan B CB Smith Peter K PK Reynolds John M JM Engel Jill J Wolfe Cameron R CR Milano Carmelo A CA Schroder Jacob N JN Davis Robert D RD Hartwig Matthew G MG Stout Jason E JE Strittholt Nancy N Maziarz Eileen K EK Saullo Jennifer Horan JH Hazen Kevin C KC Walczak Richard J RJ Vasireddy Ravikiran R Vasireddy Sruthi S McKnight Celeste M CM Anderson Deverick J DJ Sexton Daniel J DJ

Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20170401 7

<h4>Background</h4>Nontuberculous mycobacteria (NTM) commonly colonize municipal water supplies and cause healthcare-associated outbreaks. We investigated a biphasic outbreak of Mycobacterium abscessus at a tertiary care hospital.<h4>Methods</h4>Case patients had recent hospital exposure and laboratory-confirmed colonization or infection with M. abscessus from January 2013 through December 2015. We conducted a multidisciplinary epidemiologic, field, and laboratory investigation.<h4>Results</h4>T ...[more]

PMID: 28077517

Similar Datasets

Project description:Mycobacterium abscessus is a rapid growing, free-living species of bacterium that also causes lung infections in humans. Human infections are usually acquired from the environment; however, dominant circulating clones (DCCs) have emerged recently in both M. abscessus subsp. massiliense and subsp. abscessus that appear to be transmitted among humans and are now globally distributed. These recently emerged clones are potentially informative about the ecological and evolutionary mechanisms of pathogen emergence and host adaptation. The geographical distribution of DCCs has been reported, but the genomic processes underlying their transition from environmental bacterium to human pathogen are not well characterized. To address this knowledge gap, we delineated the structure of M. abscessus subspecies abscessus and massiliense using genomic data from 200 clinical isolates of M. abscessus from seven geographical regions. We identified differences in overall patterns of lateral gene transfer (LGT) and barriers to LGT between subspecies and between environmental and host-adapted bacteria. We further characterized genome reorganization that accompanied bacterial host adaptation, inferring selection pressures acting at both genic and intergenic loci. We found that both subspecies encode an expansive pangenome with many genes at rare frequencies. Recombination appears more frequent in M. abscessus subsp. massiliense than in subsp. abscessus, consistent with prior reports. We found evidence suggesting that phage are exchanged between subspecies, despite genetic barriers evident elsewhere throughout the genome. Patterns of LGT differed according to niche, with less LGT observed among host-adapted DCCs versus environmental bacteria. We also found evidence suggesting that DCCs are under distinct selection pressures at both genic and intergenic sites. Our results indicate that host adaptation of M. abscessus was accompanied by major changes in genome evolution, including shifts in the apparent frequency of LGT and impacts of selection. Differences were evident among the DCCs as well, which varied in the degree of gene content remodelling, suggesting they were placed differently along the evolutionary trajectory toward host adaptation. These results provide insight into the evolutionary forces that reshape bacterial genomes as they emerge into the pathogenic niche.

Dataset Information

Two-Phase Hospital-Associated Outbreak of Mycobacterium abscessus: Investigation and Mitigation.

Background

Methods

Results

Conclusions

Publications

Two-Phase Hospital-Associated Outbreak of Mycobacterium abscessus: Investigation and Mitigation.

Similar Datasets

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