Modern Healthcare Versus Nontuberculous Mycobacteria: Who Will Have the Upper Hand?

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.

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.

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).

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.

Investigation of healthcare infection risks from water-related organisms: Summary of CDC consultations, 2014-2017

OBJECTIVE

Water exposures in healthcare settings and during healthcare delivery can place patients at risk for infection with water-related organisms and can potentially lead to outbreaks. We aimed to describe Centers for Disease Control and Prevention (CDC) consultations involving water-related organisms leading to healthcare-associated infections (HAIs).

DESIGN

Retrospective observational study.

METHODS

We reviewed internal CDC records from January 1, 2014, through December 31, 2017, using water-related terms and organisms, excluding Legionella, to identify consultations that involved potential or confirmed transmission of water-related organisms in healthcare. We determined plausible exposure pathways and routes of transmission when possible.

RESULTS

Of 620 consultations during the study period, we identified 134 consultations (21.6%), with 1,380 patients, that involved the investigation of potential water-related HAIs or infection control lapses with the potential for water-related HAIs. Nontuberculous mycobacteria were involved in the greatest number of investigations (n = 40, 29.9%). Most frequently, investigations involved medical products (n = 48, 35.8%), and most of these products were medical devices (n = 40, 83.3%). We identified a variety of plausible water-exposure pathways, including medication preparation near water splash zones and water contamination at the manufacturing sites of medications and medical devices.

CONCLUSIONS

Water-related investigations represent a substantial proportion of CDC HAI consultations and likely represent only a fraction of all water-related HAI investigations and outbreaks occurring in US healthcare facilities. Water-related HAI investigations should consider all potential pathways of water exposure. Finally, healthcare facilities should develop and implement water management programs to limit the growth and spread of water-related organisms.