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

Risk Factors for and Outcomes Following Early Acquisition of Mycobacterium abscessus Complex After Lung Transplantation

Background

Lung transplant recipients are at increased risk of Mycobacterium abscessus complex (MABC) acquisition and invasive infection. We analyzed risk factors and outcomes of early post-lung transplant MABC acquisition.

Methods

We conducted a retrospective matched case-control study of patients who underwent lung transplant from 1/1/2012 to 12/31/2021 at a single large tertiary care facility. Cases had de novo MABC isolation within 90 days post-transplant. Controls had no positive MABC cultures and were matched 3:1 with cases based on age and transplant date. Recipient demographics and pre-/peri-operative characteristics were analyzed, and a regression model was used to determine independent risk factors for MABC acquisition. We also assessed 1-year post-transplant outcomes, including mortality.

Results

Among 1145 lung transplants, we identified 79 cases and 237 matched controls. Post-transplant mechanical ventilation for >48 hours was independently associated with MABC acquisition (adjusted odds ratio, 2.46; 95% CI, 1.29-4.72; P = .007). Compared with controls, cases required more days of hospitalization after the MABC index date (28 vs 12 days; P = .01) and had decreased 1-year post-transplant survival (78% vs 89%; log-rank P = .02). One-year mortality appeared highest for cases who acquired M. abscessus subsp. abscessus (31% mortality) or had extrapulmonary infections (43% mortality).

Conclusions

In this large case-control study, prolonged post-transplant ventilator duration was associated with early post-lung transplant MABC acquisition, which in turn was associated with increased hospital-days and mortality. Further studies are needed to determine the best strategies for MABC prevention, surveillance, and management.

Mycobacterium immunogenum acquisition from hospital tap water: a genomic and epidemiologic analysis

We identified 23 cases of Mycobacterium immunogenum respiratory acquisition linked to a colonized plumbing system at a new hospital addition. We conducted a genomic and epidemiologic investigation to assess for clonal acquisition of M. immunogenum from hospital water sources and improve understanding of genetic distances between M. immunogenum isolates. We performed whole-genome sequencing on 28 M. immunogenum isolates obtained from August 2013 to July 2021 from patients and water sources on four intensive care and intermediate units at an academic hospital. Study hospital isolates were recovered from 23 patients who experienced de novo respiratory isolation of M. immunogenum and from biofilms obtained from five tap water outlets. We also analyzed 10 M. immunogenum genomes from previously sequenced clinical (n = 7) and environmental (n = 3) external control isolates. The 38-isolate cohort clustered into three clades with pairwise single-nucleotide polymorphism (SNP) distances ranging from 0 to 106,697 SNPs. We identified two clusters of study hospital isolates in Clade 1 and one cluster in Clade 2 for which clinical and environmental isolates differed by fewer than 10 SNPs and had less than 0.5% accessory genome variation. A less restrictive combined threshold of 40 SNPs and 5% accessory genes reliably captured additional isolates that met clinical criteria for hospital acquisition, but 12 (4%) of 310 epidemiologically unrelated isolate pairs also met this threshold. Core and accessory genome analyses confirmed respiratory acquisition of multiple clones of M. immunogenum from hospital water sources to patients. When combined with epidemiologic investigation, genomic thresholds accurately distinguished hospital acquisition.

Exploring antibiotic resistance mechanisms in Mycobacterium abscessus for enhanced therapeutic approaches

Mycobacterium abscessus, a leading cause of severe lung infections in immunocompromised individuals, poses significant challenges for current therapeutic strategies due to resistance mechanisms. Therefore, understanding the intrinsic and acquired antibiotic resistance of M. abscessus is crucial for effective treatment. This review highlights the mechanisms employed by M. abscessus to sustain antibiotic resistance, encompassing not only conventional drugs but also newly discovered drug candidates. This comprehensive analysis aims to identify novel entities capable of overcoming the notorious resistance exhibited by M. abscessus, providing insights for the development of more effective therapeutic interventions.

Complete genome sequence of Mycobacterium immunogenum strain C14-1.MIM isolated from a hospitalized lung transplant recipient

Mycobacterium immunogenum is a rapidly growing nontuberculous mycobacteria species that can cause healthcare-associated infections. We report the complete genome of C14-1.MIM, isolated via culture of a respiratory specimen obtained from a hospitalized lung transplant recipient. The circular chromosome contains 5,407,919 bp with a G + C content of 64.24% and 5,217 coding sequences.

Epidemiology of Pulmonary and Extrapulmonary Nontuberculous Mycobacteria Infections at 4 US Emerging Infections Program Sites: A 6-Month Pilot

BACKGROUND

Nontuberculous mycobacteria (NTM) cause pulmonary (PNTM) and extrapulmonary (ENTM) disease. Infections are difficult to diagnose and treat, and exposures occur in healthcare and community settings. In the United States, NTM epidemiology has been described largely through analyses of microbiology data from health departments, electronic health records, and administrative data. We describe findings from a multisite pilot of active, laboratory- and population-based NTM surveillance.

METHODS

The Centers for Disease Control and Prevention's Emerging Infections Program conducted NTM surveillance at 4 sites (Colorado, 5 counties; Minnesota, 2 counties; New York, 2 counties; and Oregon, 3 counties [PNTM] and statewide [ENTM]) from 1 October 2019 through 31 March 2020. PNTM cases were defined using published microbiologic criteria. ENTM cases required NTM isolation from a nonpulmonary specimen, excluding stool and rectal swabs. Patient data were collected via medical record review.

RESULTS

Overall, 299 NTM cases were reported (PNTM: 231, 77%); Mycobacterium avium complex was the most common species group. Annualized prevalence was 7.5/100 000 population (PNTM: 6.1/100 000; ENTM: 1.4/100 000). Most patients had signs or symptoms in the 14 days before positive specimen collection (ENTM: 62, 91.2%; PNTM: 201, 87.0%). Of PNTM cases, 145 (62.8%) were female and 168 (72.7%) had underlying chronic lung disease. Among ENTM cases, 29 (42.6%) were female, 21 (30.9%) did not have documented underlying conditions, and 26 (38.2%) had infection at the site of a medical device or procedure.

CONCLUSIONS

Active, population-based NTM surveillance will provide data for monitoring the burden of disease and characterize affected populations to inform interventions.

Genomic Analyses of Longitudinal Mycobacterium abscessus Isolates in a Multicenter Cohort Reveal Parallel Signatures of In-Host Adaptation

BACKGROUND

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and an increasingly frequent cause of opportunistic infections. Mycobacterium abscessus complex (MABC) is one of the major NTM lung pathogens that disproportionately colonize and infect the lungs of individuals with cystic fibrosis (CF). MABC infection can persist for years, and antimicrobial treatment is frequently ineffective.

METHODS

We sequenced the genomes of 175 isolates longitudinally collected from 30 patients with MABC lung infection. We contextualized our cohort amidst the broader MABC phylogeny and investigated genes undergoing parallel adaptation across patients. Finally, we tested the phenotypic consequences of parallel mutations by conducting antimicrobial resistance and mercury-resistance assays.

RESULTS

We identified highly related isolate pairs across hospital centers with low likelihood of transmission. We further annotated nonrandom parallel mutations in 22 genes and demonstrated altered macrolide susceptibility co-occurring with a nonsynonymous whiB1 mutation. Finally, we highlighted a 23-kb mercury-resistance plasmid whose loss during chronic infection conferred phenotypic susceptibility to organic and nonorganic mercury compounds.

CONCLUSIONS

We characterized parallel genomic processes through which MABC is adapting to promote survival within the host. The within-lineage polymorphisms we observed have phenotypic effects, potentially benefiting fitness in the host at the putative detriment of environmental survival.

Use of Statistical Process Control Methods for Early Detection of Healthcare Facility-Associated Nontuberculous Mycobacteria Outbreaks: A Single-Center Pilot Study

BACKGROUND

Nontuberculous mycobacteria (NTM) are emerging pathogens increasingly implicated in healthcare facility-associated (HCFA) infections and outbreaks. We analyzed the performance of statistical process control (SPC) methods in detecting HCFA NTM outbreaks.

METHODS

We retrospectively analyzed 3 NTM outbreaks that occurred from 2013 to 2016 at a tertiary care hospital. The outbreaks consisted of pulmonary Mycobacterium abscessus complex (MABC) acquisition, cardiac surgery-associated extrapulmonary MABC infection, and a bronchoscopy-associated pseudo-outbreak of Mycobacterium avium complex (MAC). We analyzed monthly case rates of unique patients who had positive respiratory cultures for MABC, non-respiratory cultures for MABC, and bronchoalveolar lavage cultures for MAC, respectively. For each outbreak, we used these rates to construct a pilot moving average (MA) SPC chart with a rolling baseline window. We also explored the performance of numerous alternative control charts, including exponentially weighted MA, Shewhart, and cumulative sum charts.

RESULTS

The pilot MA chart detected each outbreak within 2 months of outbreak onset, preceding actual outbreak detection by an average of 6 months. Over a combined 117 months of pre-outbreak and post-outbreak surveillance, no false-positive SPC signals occurred (specificity, 100%). Prospective use of this chart for NTM surveillance could have prevented an estimated 108 cases of NTM. Six high-performing alternative charts detected all outbreaks during the month of onset, with specificities ranging from 85.7% to 94.9%.

CONCLUSIONS

SPC methods have potential to substantially improve HCFA NTM surveillance, promoting early outbreak detection and prevention of NTM infections. Additional study is needed to determine the best application of SPC for prospective HCFA NTM surveillance in other settings.

Epidemiology, Management, and Clinical Outcomes of Extrapulmonary Mycobacterium abscessus Complex Infections in Heart Transplant and Ventricular Assist Device Recipients

Nontuberculous mycobacteria (NTM) are emerging pathogens, yet data on the epidemiology and management of extrapulmonary NTM infections in orthotopic heart transplantation (OHT) and ventricular assist device (VAD) recipients are scarce. We retrospectively reviewed records of OHT and VAD recipients who underwent cardiac surgery at our hospital and developed Mycobacterium abscessus complex (MABC) infection from 2013-2016 during a hospital outbreak of MABC linked to heater-cooler units. We analyzed patient characteristics, medical and surgical management, and long-term outcomes. Ten OHT and 7 VAD patients developed extrapulmonary M. abscessus subspecies abscessus infection. Median time from presumed inoculation during cardiac surgery to first positive culture was 106 days in OHT and 29 days in VAD recipients. The most common sites of positive cultures were blood (n=12), sternum/mediastinum (n=8), and the VAD driveline exit site (n=7). The 14 patients diagnosed while alive received combination antimicrobial therapy for a median of 21 weeks, developed 28 antibiotic-related adverse events, and underwent 27 surgeries. Only 8 (47%) patients survived longer than 12 weeks after diagnosis, including 2 VAD patients who experienced long-term survival after explantation of infected VADs and OHT. Despite aggressive medical and surgical management, OHT and VAD patients with MABC infection experienced substantial morbidity and mortality.

Mycobacterium abscessus Cluster in Cardiac Surgery Patients Potentially Attributable to a Commercial Water Purification System

BACKGROUND

Nontuberculous mycobacteria are water-avid pathogens that are associated with nosocomial infections.

OBJECTIVE

To describe the analysis and mitigation of a cluster of Mycobacterium abscessus infections in cardiac surgery patients.

DESIGN

Descriptive study.

SETTING

Brigham and Women's Hospital, Boston, Massachusetts.

PARTICIPANTS

Four cardiac surgery patients.

INTERVENTION

Commonalities among cases were sought, potential sources were cultured, patient and environmental specimens were sequenced, and possible sources were abated.

MEASUREMENTS

Description of the cluster, investigation, and mitigation.

RESULTS

Whole-genome sequencing confirmed homology among clinical isolates. Patients were admitted during different periods to different rooms but on the same floor. There were no common operating rooms, ventilators, heater-cooler devices, or dialysis machines. Environmental cultures were notable for heavy mycobacterial growth in ice and water machines on the cluster unit but little or no growth in ice and water machines in the hospital's other 2 inpatient towers or in shower and sink faucet water in any of the hospital's 3 inpatient towers. Whole-genome sequencing confirmed the presence of a genetically identical element in ice and water machine and patient specimens. Investigation of the plumbing system revealed a commercial water purifier with charcoal filters and an ultraviolet irradiation unit leading to the ice and water machines in the cluster tower but not the hospital's other inpatient towers. Chlorine was present at normal levels in municipal source water but was undetectable downstream from the purification unit. There were no further cases after high-risk patients were switched to sterile and distilled water, ice and water machine maintenance was intensified, and the commercial purification system was decommissioned.

LIMITATION

Transmission pathways were not clearly characterized.

CONCLUSION

Well-intentioned efforts to modify water management systems may inadvertently increase infection risk for vulnerable patients.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Genomic epidemiology of Mycobacterium abscessus in a Canadian cystic fibrosis centre

The Mycobacterium abscessus complex causes significant morbidity and mortality among patients with Cystic Fibrosis (CF). It has been hypothesized that these organisms are transmitted from patient to patient based on genomics. However, few studies incorporate epidemiologic data to confirm this hypothesis. We longitudinally sampled 27 CF and 7 non-CF patients attending a metropolitan hospital in Ontario, Canada from 2013 to 2018. Whole genome sequencing along with epidemiological data was used to evaluate the likelihood of transmission. Overall, the genetic diversity of M. abscessus was large, with a median pairwise distance (IQR) of 1,279 (143-134) SNVs between all Ontario M. abscessus isolates and 2,908 (21-3,204) single nucleotide variants (SNVs) between M. massiliense isolates. This reflects the global diversity of this pathogen, with Ontario isolates widely dispersed throughout global phylogenetic trees of each subspecies. Using a maximum distance of 25 SNVs as a threshold to identify possible transmission, we identified 23 (of 276 total) pairs of closely-related isolates. However, transmission was probable for only one pair based on both genomic and epidemiological data. This suggests that person-to-person transmission of M. abscessus among CF patients is indeed rare and reinforces the critical importance of epidemiological data for inferences of transmission.

Cardiovascular device infections due to rapidly growing Mycobacteria: A review of cases at a tertiary care hospital

Cardiovascular device infection due to rapidly growing mycobacteria (RGM) is rarely encountered in clinical practice. Due to the increasing number of indications and use of cardiovascular devices in an aging population, optimized management of these infections is of great importance. We report seven cases of RGM cardiovascular device infection. Three patients had left-ventricular assist device (LVAD) infections; two patients had cardiovascular implantable device (CIED) infections; and one had an aortic vascular stent infection. Specific cardiac valvular infection was not detected among any of the patients. All patients had a high number of comorbidities which limited some patients from receiving optimal combination antimicrobial therapy. The prognosis of cardiovascular device infections with RGM is guarded with only four patients still alive; however, the treatment approach for each patient varied considerably and often based on concurrent medical conditions, overall adjustments to goals of care, and specific patient preferences. Further analysis of cardiovascular device infections with RGM is warranted to establish a more systematic approach in successful management.

Healthcare-associated links in transmission of nontuberculous mycobacteria among people with cystic fibrosis (HALT NTM) study: Rationale and study design

Background

Healthcare-associated transmission of nontuberculous mycobacteria (NTM) among people with cystic fibrosis (pwCF) has been reported and is of increasing concern. No standardized epidemiologic investigation tool has been published for healthcare-associated NTM outbreak investigations. This report describes the design of an ongoing observational study to standardize the approach to NTM outbreak investigation among pwCF.

Methods

This is a parallel multi-site study of pwCF within a single Center who have respiratory NTM isolates identified as being highly-similar. Participants have a history of positive airway cultures for NTM, receive care within a single Center, and have been identified as part of a possible outbreak based on genomic analysis of NTM isolates. Participants are enrolled in the study over a 3-year period. Primary endpoints are identification of a shared healthcare-associated encounter(s) among patients in a Center and identification of environmental isolates that are genetically highly-similar to respiratory isolates recovered from pwCF. Secondary endpoints include characterization of potential transmission modes and settings, as well as incidence and prevalence of healthcare-associated environmental NTM species/subspecies by geographical region.

Discussion

We hypothesize that genetically highly-similar strains of NTM among pwCF cared for at the same Center may arise from healthcare sources including patient-to-patient transmission and/or acquisition from environmental sources. This novel study design will establish a standardized, evidence-based epidemiologic investigation tool for healthcare-associated NTM outbreak investigation within CF Care Centers, will broaden the scope of independent outbreak investigations and demonstrate the frequency and nature of healthcare-associated NTM transmission in CF Care Centers nationwide. Furthermore, it will provide valuable insights into modeling risk factors associated with healthcare-associated NTM transmission and better inform future infection prevention and control guidelines. This study will systematically characterize clinically-relevant NTM isolates of CF healthcare environmental dust and water biofilms and set the stage to describe the most common environmental sources within the healthcare setting harboring clinically-relevant NTM isolates.

Trial registration

ClinicalTrials.gov NCT04024423. Date of registry July 18, 2019.

Bloodstream infections with rapidly growing nontuberculous mycobacteria

Background

Bloodstream infections (BSI) with rapidly growing mycobacteria (RGM) resulted in recent nosocomial outbreaks predominantly in immunocompromised patients. A little is known about the clinical implications of RGM BSI with different species.

Methods

We conducted a multicenter retrospective cohort study of patients with RGM BSI from November 2011 to December 2020. Demographic data, clinical presentation, laboratory and radiographic findings and microbiological characteristics were used to tabulate descriptive statistics. We performed a comparative analysis of patients with BSI due to Mycobacterium abscessus complex (MABC) vs. other RGM.

Results

We identified 32 patients with positive blood cultures for RGM, 4/32 (12.5%) were considered to have unclear significance. The most common source for RGM BSI was intravascular catheters (14/28, 50%). Compared to other sources, patients with catheter-related bloodstream infection (CRBSI) received a shorter course of antimicrobial therapy (median [IQR]: one month [0.37–2.25] vs. six months [2–12]), (P = 0.01). The most common species isolated were MABC (12/28, 42.9%), followed by Mycobacterium fortuitum group (6/28, 21.4%) and Mycobacterium chelonae (6/28, 21.4%). Compared to other RGM, MABC BSI was more likely to be secondary to skin and soft tissue infection, associated with longer hospital stay (P = 0.04) and higher death rates despite a higher number of antimicrobial agents used for empirical and directed therapy per patient.

Conclusion

MABC BSI is associated with an overall more resistant profile, longer hospital stay, and higher death rate despite a more aggressive therapy approach.

Successful treatment of rapid growing mycobacterial infections with source control alone: Case series

Rapid growing mycobacteria have been increasingly recognized as pathogens, both in immunocompromised and immunocompetent population, and their incidence has increased over the last decade significantly. Pulmonary infections are the most common, however, any organ can be affected. The treatment of these infections is costly, prolonged, and often antimicrobial resistance poses a significant challenge to a successful outcome. The source control together with antimicrobials is the cornerstone of treatment. We report a case series of 3 patients with extrapulmonary rapid growing mycobacterial infections in whom the successful treatment was achieved with source control alone.

Genomic Analysis of a Hospital-Associated Outbreak of Mycobacterium abscessus: Implications on Transmission

Whole genome sequencing (WGS) has recently been used to investigate acquisition of Mycobacterium abscessus (MABC). Investigators have reached conflicting conclusions about the meaning of genetic distances for interpretation of person-to-person transmission. Existing genomic studies were limited by a lack of WGS from environmental MABC isolates. In this study, we retrospectively analyzed the core and accessory genomes of 26 M. abscessus subsp. abscessus (MAA) isolates collected over seven years. Clinical isolates (n=22) were obtained from a large hospital-associated outbreak of MAA, the outbreak hospital before or after the outbreak, a neighboring hospital, and two outside laboratories. Environmental MAA isolates (n=4) were obtained from outbreak hospital water outlets. Phylogenomic analysis of study isolates revealed three clades with pairwise genetic distances ranging from 0-135 single nucleotide polymorphisms (SNPs). Compared to a reference environmental outbreak isolate, all seven clinical outbreak isolates and the remaining three environmental isolates had highly similar core and accessory genomes, differing by up to 7 SNPs and a median of 1.6% accessory genes, respectively. Although genomic comparisons of 15 non-outbreak clinical isolates revealed greater heterogeneity, five (33%) isolates had fewer than 20 SNPs compared to the reference environmental isolate, including two unrelated outside laboratory isolates with less than 4% accessory genome variation. Detailed genomic comparisons confirmed environmental acquisition of outbreak isolates of MAA. SNP distances alone, however, did not clearly differentiate the mechanism of acquisition of outbreak versus non-outbreak isolates. We conclude that successful investigation of MAA clusters requires molecular and epidemiologic components, ideally complemented by environmental sampling.

Tap Water Avoidance Decreases Rates of Hospital-onset Pulmonary Nontuberculous Mycobacteria

We analyzed the impact of a hospital tap water avoidance protocol on respiratory isolation of nontuberculous mycobacteria (NTM). After protocol implementation, hospital-onset episodes of respiratory NTM isolation on high-risk units decreased from 41.0 to 9.9 episodes per 10 000 patient-days (incidence rate ratio, 0.24; 95% confidence interval, .17-.34; P < .0001).

A Molecular-Beacon-Based Multiplex Real-Time PCR Assay To Distinguish Mycobacterium abscessus Subspecies and Determine Macrolide Susceptibility

Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterial species that comprises three subspecies: M. abscessus subsp. abscessus, M. abscessus subsp. massiliense, and M. abscessus subsp. bolletii. These predominantly environmental microorganisms have emerged as life-threatening chronic pulmonary pathogens in both immunocompetent and immunocompromised patients, and their acquisition of macrolide resistance due to the erm(41) gene and mutations in the 23S rrl gene has dramatically impacted patient outcome. However, standard microbiology laboratories typically have limited diagnostic tools to distinguish M. abscessus subspecies, and the testing for macrolide resistance is often not done. Here, we describe the development of a real-time multiplex assay using molecular beacons to establish a robust, rapid, and highly accurate method to both distinguish M. abscessus subspecies and to determine which strains are susceptible to macrolides. We report a bioinformatic approach to identify robust subspecies sequence targets, the design and optimization of six molecular beacons to identify all genotypes, and the development and application of a 2-tube 3-color multiplex assay that can provide clinically significant treatment information in less than 3 h.

Reduction in Expected Survival Associated With Nontuberculous Mycobacterial Pulmonary Disease

BACKGROUND

Nontuberculous mycobacteria (NTM) are opportunistically pathogenic bacteria that are found abundantly in the soil and water. Susceptible individuals exposed to NTM-containing aerosols from environmental sources may develop NTM pulmonary disease (NTM-PD). Reported survival after NTM-PD diagnosis varies widely among existing studies. Prior work has suggested that mortality among persons with NTM-PD is primarily driven by comorbidities rather than NTM-PD.

METHODS

We retrospectively identified a cohort of patients in the Duke University Health System who were diagnosed with NTM-PD between 1996 and 2015. Hospitalizations and survival were compared among patients with NTM-PD with and without other comorbidities. Additionally, survival among patients with NTM-PD was compared with standardized mortality data for a similar cohort of the general population.

RESULTS

Patients with NTM-PD without other comorbidities had 0.65 hospitalizations/1000 patient-days compared with 1.37 hospitalizations/1000 patient-days for patients with other comorbidities. Compared with a cohort of the general population, expected survival decreased by approximately 4 years for a diagnosis of NTM-PD without comorbidities and 8.6 years for a diagnosis of NTM-PD with comorbidities. Mortality 5 years after diagnosis was 25.0% and 44.9% among NTM patients without and with comorbidities, respectively, compared with 5.7% in the general-population cohort.

CONCLUSIONS

NTM-PD was associated with significant morbidity that was worse in patients with comorbidities. Patients with NTM-PD, even without comorbidities, had worse survival than expected.

Invasive Mycobacterium abscessus Complex Infection After Cardiac Surgery: Epidemiology, Management, and Clinical Outcomes

BACKGROUND

We recently mitigated a clonal outbreak of hospital-acquired Mycobacterium abscessus complex (MABC), which included a large cluster of adult patients who developed invasive infection after exposure to heater-cooler units during cardiac surgery. Recent studies have detailed Mycobacterium chimaera infections acquired during cardiac surgery; however, little is known about the epidemiology and clinical courses of cardiac surgery patients with invasive MABC infection.

METHODS

We retrospectively collected clinical data on all patients who underwent cardiac surgery at our hospital and subsequently had positive cultures for MABC from 2013 through 2016. Patients with ventricular assist devices or heart transplants were excluded. We analyzed patient characteristics, antimicrobial therapy, surgical interventions, and clinical outcomes.

RESULTS

Ten cardiac surgery patients developed invasive, extrapulmonary infection from M. abscessus subspecies abscessus in an outbreak setting. Median time from presumed inoculation in the operating room to first positive culture was 53 days (interquartile range [IQR], 38-139 days). Disseminated infection was common, and the most frequent culture-positive sites were mediastinum (n = 7) and blood (n = 7). Patients received a median of 24 weeks (IQR, 5-33 weeks) of combination antimicrobial therapy that included multiple intravenous agents. Six patients required antibiotic changes due to adverse events attributed to amikacin, linezolid, or tigecycline. Eight patients underwent surgical management, and 6 patients required multiple sternal debridements. Eight patients died within 2 years of diagnosis, including 4 deaths directly attributable to MABC infection.

CONCLUSIONS

Despite aggressive medical and surgical management, invasive MABC infection after cardiac surgery caused substantial morbidity and mortality. New treatment strategies are needed, and compliance with infection prevention guidelines remains critical.

Mycobacterium chimaera Genomics With Regard to Epidemiological and Clinical Investigations Conducted for an Open Chest Postsurgical Mycobacterium chimaera Infection Outbreak

Background

Postsurgical infections due to Mycobacterium chimaera appeared as a novel nosocomial threat in 2015, with a worldwide outbreak due to contaminated heater-cooler units used in open chest surgery. We report the results of investigations conducted in France including whole-genome sequencing comparison of patient and heater-cooler unit isolates.

Methods

We sought M. chimaera infection cases from 2010 onwards through national epidemiological investigations in health care facilities performing cardiopulmonary bypass, together with a survey on good practices and systematic heater-cooler unit microbial analyses. Clinical and heater-cooler unit isolates were subjected to whole-genome sequencing analyzed with regard to the reference outbreak strain Zuerich-1.

Results

Only 2 clinical cases were shown to be related to the outbreak, although 23% (41/175) of heater-cooler units were declared positive for M. avium complex. Specific measures to prevent infection were applied in 89% (50/56) of health care facilities, although only 14% (8/56) of them followed the manufacturer maintenance recommendations. Whole-genome sequencing comparison showed that the clinical isolates and 72% (26/36) of heater-cooler unit isolates belonged to the epidemic cluster. Within clinical isolates, 5–9 nonsynonymous single nucleotide polymorphisms were observed, among which an in vivo mutation in a putative efflux pump gene was observed in a clinical isolate obtained for 1 patient on antimicrobial treatment.

Conclusions

Cases of postsurgical M. chimaera infections have been declared to be rare in France, although heater-cooler units were contaminated, as in other countries. Genomic analyses confirmed the connection to the outbreak and identified specific single nucleotide polymorphisms, including 1 suggesting fitness evolution in vivo.

Efficacy and Effectiveness of Showerheads Attached with Point-of-use (POU) Filter Capsules in Preventing Waterborne Diseases in a Japanese Hospital

Tap water contamination is a growing concern in healthcare facilities, and despite chlorination, tap water in these facilities contains several pathogenic microorganisms causing healthcare-associated waterborne infections or nosocomial outbreaks. Shower units are particularly prone to contamination as they are conducive for bacterial growth and can even produce bioaerosols containing pathogenic bacteria. Shower units coupled with point-of-use (POU) water filters are a simple and safe option; however, their efficacy has been under-reported. Therefore, we determined the efficacy of showerheads attached with a POU filter capsule in preventing infections in our hospital. We investigated the presence of pathogenic bacteria in water sampled from three shower units. After replacing the original shower units with new ones incorporated with a sterile-grade water filter capsule (0.2 µm; QPoint™), the water samples were analyzed for up to 2 months. The POU filters removed several pathogenic bacteria (Mycobacterium, Pseudomonas, Stenotrophomonas, Aeromonas, and Klebsiella spp.). Filter effectiveness depends on regional water quality and we believe that effective tap water treatment combined with the use of POU filters (introduced at a reasonable cost in healthcare facilities) can considerably minimize waterborne diseases in hospitals and improve patient care.

Persistence of Legionella in Routinely Disinfected Heater-Cooler Units and Heater Units assessed by Propidium Monoazide qPCR

BACKGROUND

Evidence to date indicates that heater-cooler units (HCUs) and heater units (HUs) can generate potentially infectious aerosols containing a range of opportunistic pathogens such as Mycobacterium chimaera, other non-tuberculous mycobacterial (NTM) species, Pseudomonas aeruginosa and Legionella spp. Our purpose was to determine the extent of Legionella contamination and total viable count (TVC) in HCUs and HUs and to analyze the relationship by water system design of devices of two different brands (LivaNova vs. Maquet).

METHODS

Legionella spp. were detected and quantified by our optimized PMA-qPCR protocol; TVCs were assessed according to ISO protocol 6222. Analyses were performed in the first sampling round and after six months of surveillance.

RESULTS

Overall, Legionella spp. was detected in 65.7% of devices. In the second sampling round, Legionella positivity rates were significantly lower in water samples from the Maquet devices compared to the LivaNova ones (27.3% vs. 61.5%). LivaNova HCUs also yielded more Legionella, and aquatic bacteria counts than Maquet in both first and second-round samples.

CONCLUSIONS

We recommend that all surgical patients and staff exposed to aerosols from thermoregulatory devices should be followed up for Legionella infection and that microbiological surveillance on such devices should be conducted regularly as precautionary principle.

Disseminated Disease by Mycobacterium abscessus and Mycobacterium celatum in an Immunocompromised Host

BACKGROUND Nontuberculous mycobacteria (NTM) are environmental pathogens that cause an increasing number of diseases, in particular in immunosuppressed patients. Diagnosing NTM infections may be difficult because clinical presentation is unspecific and resembles other conditions such as tuberculosis, lymphomas, or septicemia. CASE REPORT We report the case of a 62-year-old male with a recent history of autologous bone marrow transplantation for a follicular lymphoma admitted to our department for long-lasting remittent fever and abscess-like splenic nodules. The patient was diagnosed with mixed systemic infection by Mycobacterium abscessus and Mycobacterium celatum localized in spleen, bone marrow and kidneys. CONCLUSIONS In this case a rare disseminated atypical mycobacteriosis was diagnosed and treated. As far as we know this is the first case in the literature of M. abscessus localization either in the spleen or in the bone marrow. Our patient underwent a complex long-term therapy and had a complete resolution of the disease.

Water Management for Construction: Evidence for Risk Characterization in Community and Healthcare Settings: A Systematic Review

Construction activities are a known risk contributing to the growth and spread of waterborne pathogens in building water systems. The purpose of the study is to integrate evidence for categorizing construction activity risk factors contributing to waterborne disease in community and healthcare settings, establish severity of such risk factors and identify knowledge gaps. Using a systematic review, the inclusion criteria were: 1) studies with disease cases suspected to be associated with construction activities and waterborne pathogens, and 2) active construction work described in a community or healthcare setting. Each construction activity risk factor was correlated across all studies with the number of disease cases and deaths to establish risk severity. The eligibility review and quantitative synthesis yielded 31 studies for inclusion (community, n = 7 and healthcare, n = 24). From 1965 to 2016, a total of 894 disease cases inclusive of 112 deaths were associated with nine construction activity risk factors and waterborne pathogens. The present study findings support the need for building owners, water management teams and public health professionals to address construction activity risk factors and the analysis of current knowledge deficiencies within the scope of an ongoing water management program. The impact of construction activities on waterborne disease is preventable and should no longer be considered incidental nor accidental.

Comparing the Utilities of Different Multilocus Sequence Typing Schemes for Identifying Outbreak Strains of Mycobacterium abscessus subsp. massiliense

Outbreaks of infections by Mycobacterium abscessus, particularly subspecies massiliense, are increasingly reported worldwide. Several multilocus sequence typing (MLST) protocols for grouping international outbreak strains have been developed but not yet directly compared. Using the three-gene (hsp65, rpoB, and secA1), seven-gene (argH, cya, glpK, gnd, murC, pta, and purH) and thirteen-gene (all of the preceding genes plus gdhA, pgm, and pknA) MLST schemes, we identified 22, 38, and 40 unique sequence types (STs), respectively, among a total of 139 nonduplicated M. abscessus isolates. Among subspecies massiliense, three-gene MLST not only clustered all outbreak strains together (in 100% agreement with the seven-gene and thirteen-gene schemes), but it also distinguished between two new STs that would have been grouped together by the seven-gene MLST but were distinct by the thirteen-gene MLST owing to differences in hsp65, rpoB, and pknA Here, we show that an abbreviated MLST may be useful for simultaneous identification of M. abscessus the subspecies level and screening M. abscessus subsp. massiliense isolates with outbreak potential.

Revisiting John Snow to Meet the Challenge of Nontuberculous Mycobacterial Lung Disease

Nontuberculous mycobacteria (NTM) are ubiquitous components of the soil and surface water microbiome. Disparities by sex, age, and geography demonstrate that both host and environmental factors are key determinants of NTM disease in populations, which predominates in the form of chronic pulmonary disease. As the incidence of NTM pulmonary disease rises across the United States, it becomes increasingly evident that addressing this emerging human health issue requires a bold, multi-disciplinary research framework that incorporates host risk factors for NTM pulmonary disease alongside the determinants of NTM residence in the environment. Such a framework should include the assessment of environmental characteristics promoting NTM growth in soil and surface water, detailed evaluations of water distribution systems, direct sampling of water sources for NTM contamination and species diversity, and studies of host and bacterial factors involved in NTM pathogenesis. This comprehensive approach can identify intervention points to interrupt the transmission of pathogenic NTM species from the environment to the susceptible host and to reduce NTM pulmonary disease incidence.

[Breast pain and fever in a 46-year-old immunosuppressed patient with breast implants]

A 46-year-old immunosuppressed patient presented with a breast implant-associated infection 10 years after breast augmentation in Southeast Asia. No pathogen was identified in the initial conventional microbiological workup. Subsequently, infection with Mycobacterium abscessus-a nontuberculous mycobacteria-was diagnosed using a special culture technique. Increased rates of such infections are reported after cosmetic surgery in foreign countries, presumably due to inoculation with these ubiquitous pathogens. This case highlights the fact that the differential diagnosis and thus the microbiological workup should be extended in cases without initial pathogen detection.

In Vitro Susceptibility Testing of Bedaquiline against Mycobacterium abscessus Complex

We performed bedaquiline broth microdilution susceptibility testing using Clinical and Laboratory Standards Institute (CLSI) guidelines on 104 nonduplicate isolates of Mycobacterium abscessus complex [M. abscessus subsp. abscessus (76); M. abscessus subsp. massiliense (10); M. abscessus subsp. bolletii (2); and M. abscessus subsp. abscessus-M. abscessus subsp. massiliense hybrid, i.e., M. abscessus subsp. abscessus by rpoB gene and M. abscessus subsp. massiliense by erm(41) gene (16)]. All isolates from patients not known to have been on bedaquiline prior had MIC values of ≤0.25 μg/ml. The bedaquiline MIC₅₀ value for all 76 isolates of M. abscessus subsp. abscessus and 16 isolates of M. abscessus subsp. abscessus-M. abscessus subsp. massiliense hybrid was 0.06 μg/ml. The MIC₅₀ and MIC₉₀ values for 10 isolates of M. abscessus subsp. massiliense were 0.12 μg/ml. Only two isolates of M. abscessus subsp. bolletii were tested with bedaquiline MICs of 0.06 μg/ml. Our study suggests that oral bedaquiline may have potential use in the treatment of disease caused by the M. abscessus complex. Combination therapy with other agents (imipenem, cefoxitin, amikacin, and/or tigecycline) is recommended.

Biodiversity-ecosystem function relationships on bodies and in buildings

Biodiversity underpins the function of ecosystems. Here we discuss how biodiversity–ecosystem function theory could apply to our bodies and buildings, outline practical applications and call for further research.

MYCOBACTERIUM CHIMAERA INFECTIONS AFTER CARDIOVASCULAR SURGERY: LESSONS FROM A GLOBAL OUTBREAK

A global outbreak of invasive Mycobacterium chimaera infections has been associated with exposure to certain heater-cooler devices (HCDs) used during cardiopulmonary bypass. Outbreak investigations have shown that these HCDs harbor M. chimaera in water circuits and generate bio-aerosols in the operating room, leading to airborne transmission to patients during surgery. Whole genome sequencing data support a common-source outbreak originating at an HCD manufacturing facility. Most clinical infections are associated with implanted devices, diagnosis is often delayed, and treatment requires device removal and prolonged antibiotic therapy. Because it is nearly impossible to eradicate M. chimaera from HCDs using existing disinfection approaches, strict separation of HCD exhaust from operating room air is necessary to prevent patient exposure. Lessons learned from this outbreak include: 1) medical device risks are difficult to predict, requiring improved expert review before approval, and 2) advances in genomics provide powerful tools for outbreak investigation and public health surveillance.

A Closer Look at the Genomic Variation of Geographically Diverse Mycobacterium abscessus Clones That Cause Human Infection and Disease

Mycobacterium abscessus is a multidrug resistant bacterium that causes pulmonary and extrapulmonary disease. The reported prevalence of pulmonary M. abscessus infections appears to be increasing in the United States (US) and around the world. In the last five years, multiple studies have utilized whole genome sequencing to investigate the genetic epidemiology of two clinically relevant subspecies, M. abscessus subsp. abscessus (MAB) and M. abscessus subsp. massiliense (MMAS). Phylogenomic comparisons of clinical isolates revealed that substantial proportions of patients have MAB and MMAS isolates that belong to genetically similar clusters also known as ‘dominant clones’. Unlike the genetic lineages of Mycobacterium tuberculosis that tend to be geographically clustered, the MAB and MMAS clones have been found in clinical populations from the US, Europe, Australia and South America. Moreover, the clones have been associated with worse clinical outcomes and show increased pathogenicity in macrophage and mouse models. While some have suggested that they may have spread locally and then globally through ‘indirect transmission’ within cystic fibrosis (CF) clinics, isolates of these clones have also been associated with sporadic pulmonary infections in non-CF patients and unrelated hospital-acquired soft tissue infections. M. abscessus has long been thought to be acquired from the environment, but the prevalence, exposure risk and environmental reservoirs of the dominant clones are currently not known. This review summarizes the genomic studies of M. abscessus and synthesizes the current knowledge surrounding the geographically diverse dominant clones identified from patient samples. Furthermore, it discusses the limitations of core genome comparisons for studying these genetically similar isolates and explores the breadth of accessory genome variation that has been observed to date. The combination of both core and accessory genome variation among these isolates may be the key to elucidating the origin, spread and evolution of these frequent genotypes.

An Update in Antimicrobial Therapies and Infection Prevention in Pediatric Lung Transplant Recipients

Lung transplantation can offer life-prolonging therapy to children with otherwise terminal end-stage lung disease. However, infectious complications, like those experienced by their adult counterparts, are a significant cause of morbidity and mortality. These include bacteria, viruses, and fungi that infect the patient pretransplant and those that may be acquired from the donor or by the recipient in the months to years posttransplant. An understanding of the approach to the management of each potential infecting organism is required to ensure optimal outcomes. In particular, emphasis on aggressive preoperative management of infections in pediatric patients with cystic fibrosis is important. These include multidrug-resistant Gram-negative bacteria, fungi, and Mycobacterium abscessus, the posttransplant outcome of which depends on optimal pretransplant management, including vaccination and other preventive, antibiotic-sparing strategies. Similarly, increasing the transplant donor pool to meet rising transplant demands is an issue of critical importance. Expanded-criteria donors-those at increased risk of blood-borne viruses in particular-are increasingly being considered and transplants undertaken to meet the rising demand. There is growing evidence in the adult pool that these transplants are safe and associated with comparable outcomes. Pediatric transplanters are therefore likely to be presented with increased-risk donors for their patients. Finally, numerous novel antibiotic-sparing therapeutic approaches are on the horizon to help combat infections that currently compromise transplant outcomes.

Assessing Response to Therapy for Nontuberculous Mycobacterial Lung Disease: Quo Vadis?

Assessing progression of disease or response to treatment remains a major challenge in the clinical management of nontuberculous mycobacterial (NTM) infections of the lungs. Serial assessments of validated measures of treatment response address whether the current therapeutic approach is on track toward clinical cure, which remains a fundamental question for clinicians and patients during the course of NTM disease treatment. The 2015 NTM Research Consortium Workshop, which included a patient advisory panel, identified treatment response biomarkers as a priority area for investigation. Limited progress in addressing this challenge also hampers drug development efforts. The Biomarker Qualification Program at the FDA supports the use of a validated treatment response biomarker across multiple drug development programs. Current approaches in clinical practice include microbiologic and radiographic monitoring, along with symptomatic and quality-of-life assessments. Blood-based monitoring, including assessments of humoral and cell-mediated NTM-driven immune responses, remain under investigation. Alignment of data collection schemes in prospective multicenter studies, including the support of biosample repositories, will support identification of treatment response biomarkers under standard-of-care and investigational therapeutic strategies. In this review, we outline the role of treatment monitoring biomarkers in both clinical practice and drug development frameworks.

In Silico Screen and Structural Analysis Identifies Bacterial Kinase Inhibitors which Act with β-Lactams To Inhibit Mycobacterial Growth

New tools and concepts are needed to combat antimicrobial resistance. Actinomycetes and firmicutes share several eukaryotic-like Ser/Thr kinases (eSTK) that offer antibiotic development opportunities, including PknB, an essential mycobacterial eSTK. Despite successful development of potent biochemical PknB inhibitors by many groups, clinically useful microbiologic activity has been elusive. Additionally, PknB kinetics are not fully described, nor are structures with specific inhibitors available to inform inhibitor design. We used computational modeling with available structural information to identify human kinase inhibitors predicted to bind PknB, and we selected hits based on drug-like characteristics intended to increase the likelihood of cell entry. The computational model suggested a family of inhibitors, the imidazopyridine aminofurazans (IPAs), bind PknB with high affinity. We performed an in-depth characterization of PknB and found that these inhibitors biochemically inhibit PknB, with potency roughly following the predicted models. A novel X-ray structure confirmed that the inhibitors bound as predicted and made favorable protein contacts with the target. These inhibitors also have antimicrobial activity toward mycobacteria and nocardia. We demonstrated that the inhibitors are uniquely potentiated by β-lactams but not antibiotics traditionally used to treat mycobacteria, consistent with PknB's role in sensing cell wall stress. This is the first demonstration in the phylum actinobacteria that some β-lactam antibiotics could be more effective if paired with a PknB inhibitor. Collectively, our data show that in silico modeling can be used as a tool to discover promising drug leads, and the inhibitors we discovered can act with clinically relevant antibiotics to restore their efficacy against bacteria with limited treatment options.

Mycobacterium abscessus: Shapeshifter of the Mycobacterial World

In this review we will focus on unique aspects of Mycobacterium abscessus (MABS) which we feel earn it the designation of "shapeshifter of the mycobacterial world." We will review its emergence as a distinct species, the recognition and description of MABS subspecies which are only now being clearly defined in terms of pathogenicity, its ability to exist in different forms favoring a saprophytic lifestyle or one more suitable to invasion of mammalian hosts, as well as current challenges in terms of antimicrobial therapy and future directions for research. One can see in the various phases of MABS, a species transitioning from a free living saprophyte to a host-adapted pathogen.

Infections after lung transplantation

The good clinical result of lung transplantation is constantly undermined by the high incidence of infection, which negatively impacts on function and survival. Moreover, infections may also have immunological interactions that play a role in the acute rejection and in the development of chronic lung allograft dysfunction. There is a temporal sequence in the types of infection that affects lung allograft: in the first postoperative month bacteria are the most frequent cause of infection; following this phase, cytomegalovirus and Pneumocystis carinii are common. Fungal infections are particularly feared due to their association with bronchial complication and high mortality. Scrupulous postoperative surveillance is mandatory for the successful management of lung transplantation patients with respect to early detection and treatment of infections. This paper is aimed to address clinicians in the management of the major infectious complications that affect the lung transplant population.

Single-Center Long-Term Analysis of Combined Liver-Lung Transplant Outcomes

Background

Combined lung-liver transplantation (LLT) applies 2 technically challenging transplants in 1 patient with severe 2-organ failure.

Methods

Institutional medical records and United Network for Organ Sharing database were queried for patients at our institution that underwent LLT from 2000 to 2016.

Results

Twelve LLTs were performed from 2000 to 2016 including 9 male and 3 female recipients with a median age of 28.36 years. Indications for lung transplantation were cystic fibrosis (8), idiopathic pulmonary fibrosis (3), and pulmonary fibrosis secondary to hepatopulmonary syndrome (1). Indications for liver transplantation were cystic fibrosis (8), alcoholic cirrhosis (1), idiopathic cirrhosis (2), and alpha-1 antitrypsin deficiency (1). Median forced expiratory volume in 1 second at transplant was 27.8% (±20.38%), and mean Model for End-Stage Liver Disease was 10.5 (±4.68). Median hospital stay was 44.5 days. Seventy-five percent of recipients had 1+ new infection during their transplant hospitalization. Patients experienced 0.68 incidences of acute rejection per year with a 41.7% (95% confidence interval, 21.3%-81.4%) probability of freedom from rejection in the first-year. Patient survival was 100% at 30 days, 91.6% at 1 year, and 71.3% at 3 years. At the time of analysis, 7 of 12 patients were alive, of whom 3 survived over 8 years post-LLT. Causes of death were primary liver graft failure (1), bronchiolitis obliterans syndrome (2), and solid tumor malignancies (2).

Conclusions

Our results indicate that LLT is associated with comparable survival to other LLT series and provides a granular assessment of infectious and rejection rates in this rare population.

Mycobacterium abscessus Complex Infections: A Retrospective Cohort Study

Background

Infections caused by Mycobacterium abscessus group strains are usually resistant to multiple antimicrobials and challenging to treat worldwide. We describe the risk factors, treatment, and clinical outcomes of patients in 2 large academic medical centers in the United States.

Methods

A retrospective cohort study of hospitalized adults with a positive culture for M. abscessus in Miami, Florida (January 1, 2011, to December 31, 2014). Demographics, comorbidities, the source of infection, antimicrobial susceptibilities, and clinical outcomes were analyzed. Early treatment failure was defined as death and/or infection relapse characterized either by persistent positive culture for M. abscessus within 12 weeks of treatment initiation and/or lack of radiographic improvement.

Results

One hundred eight patients were analyzed. The mean age was 50.81 ± 21.03 years, 57 (52.8%) were females, and 41 (38%) Hispanics. Eleven (10.2%) had end-stage renal disease, 34 (31.5%) were on immunosuppressive therapy, and 40% had chronic lung disease. Fifty-nine organisms (54.6%) were isolated in respiratory sources, 21 (19.4%) in blood, 10 (9.2%) skin and soft tissue, and 9 (8.3%) intra-abdominal. Antimicrobial susceptibility reports were available for 64 (59.3%) of the patients. Most of the isolates were susceptible to clarithromycin, amikacin, and tigecycline (93.8%, 93.8%, and 89.1%, respectively). None of the isolates were susceptible to trimethoprim/sulfamethoxazole, and only 1 (1.6%) was susceptible to ciprofloxacin. Thirty-six (33.3%) patients early failed treatment; of those, 17 (15.7%) died while hospitalized. On multivariate analysis, risk factors significantly associated with early treatment failure were disseminated infection (odds ratio [OR], 11.79; 95% confidence interval [CI], 1.53–81.69; P = .04), acute kidney injury (OR, 6.55; 95% CI, 2.4–31.25; P = .018), organ transplantation (OR, 2.37; 95% CI, 2.7–23.1; P = .005), immunosuppressive therapy (OR, 2.81; 95% CI, 1.6–21.4; P = .002), intravenous amikacin treatment (OR, 4.1; 95% CI, 0.9–21; P = .04), clarithromycin resistance (OR,79.5; 95% CI, 6.2–3717.1, P < .001), and presence of prosthetic device (OR, 5.43; 95% CI, 1.57–18.81; P = .008). Receiving macrolide treatment was found to be protective against early treatment failure (OR, 0.13; 95% CI, 0.002–1.8; P = .04).

Conclusions

Our cohort of 108 M. abscessus complex isolates in Miami, Florida, showed an in-hospital mortality of 15.7%. Most infections were respiratory. Clarithromycin and amikacin were the most likely agents to be susceptible in vitro. Resistance to fluoroquinolone and trimethoprim/sulfamethoxazole was highly common. Macrolide resistance, immunosuppression, and renal disease were significantly associated with early treatment failure.

Systematic Review and Meta-analyses of the Effect of Chemotherapy on Pulmonary Mycobacterium abscessus Outcomes and Disease Recurrence

In pharmacokinetic/pharmacodynamic models of pulmonary Mycobacterium abscessus complex, the recommended macrolide-containing combination therapy has poor kill rates. However, clinical outcomes are unknown. We searched the literature for studies published between 1990 and 2017 that reported microbial outcomes in patients treated for pulmonary M. abscessus disease. A good outcome was defined as sustained sputum culture conversion (SSCC) without relapse. Random effects models were used to pool studies and estimate proportions of patients with good outcomes. Odds ratios (OR) and 95% confidence intervals (CI) were computed. Sensitivity analyses and metaregression were used to assess the robustness of findings. In 19 studies of 1,533 patients, combination therapy was administered to 508 patients with M. abscessus subsp. abscessus, 204 with M. abscessus subsp. massiliense, and 301 with M. abscessus with no subspecies specified. Macrolide-containing regimens achieved SSCC in only 77/233 (34%) new M. abscessus subsp. abscessus patients versus 117/141 (54%) M. abscessus subsp. massiliense patients (OR, 0.108 [95% CI, 0.066 to 0.181]). In refractory disease, SSCC was achieved in 20% (95% CI, 7 to 36%) of patients, which was not significantly different across subspecies. The estimated recurrent rates per month were 1.835% (range, 1.667 to 3.196%) for M. abscessus subsp. abscessus versus 0.683% (range, 0.229 to 1.136%) for M. abscessus subsp. massiliense (OR, 6.189 [95% CI, 2.896 to 13.650]). The proportion of patients with good outcomes was 52/223 (23%) with M. abscessus subsp. abscessus versus 118/141 (84%) with M. abscessus subsp. massiliense disease (OR, 0.059 [95% CI, 0.034 to 0.101]). M. abscessus subsp. abscessus pulmonary disease outcomes with the currently recommended regimens are atrocious, with outcomes similar to those for extensively drug-resistant tuberculosis. Therapeutically, the concept of nontuberculous mycobacteria is misguided. There is an urgent need to craft entirely new treatment regimens.