Reemergence of Mycobacterium chimaera in Heater-Cooler Units despite Intensified Cleaning and Disinfection Protocol

Impact of Mycobacteroides abscessus colony morphology on biofilm formation and antimicrobial resistance

Mycobacteroides abscessus is one of the most resistant bacteria so far known and causes severe and hard to treat lung infections in predisposed patients such as those with Cystic Fibrosis (CF). Further, it causes nosocomial infections by forming biofilms on medical devices or water reservoirs. An eye-catching feature of M. abscessus is the growth in two colony morphotypes. Depending on the presence or absence of glycopeptidolipids on the cell surface, it forms smooth or rough colonies. In this study, a porous glass bead biofilm model was used to compare biofilm formation, biofilm organization and biofilm matrix composition in addition to the antimicrobial susceptibility of M. abscessus biofilms versus suspensions of isogenic (smooth and rough) patient isolates. Both morphotypes reached the same cell densities in biofilms. The biofilm architecture, however, was dramatically different with evenly distributed oligo-layered biofilms in smooth isolates, compared to tightly packed, voluminous biofilm clusters in rough morphotypes. Biofilms of both morphotypes contained more total biomass of the matrix components protein, lipid plus DNA than was seen in corresponding suspensions. The biofilm mode of growth of M. abscessus substantially increased resistance to the antibiotics amikacin and tigecycline. Tolerance to the disinfectant peracetic acid of both morphotypes was increased when grown as biofilm, while tolerance to glutaraldehyde was significantly increased in biofilm of smooth isolates only. Overall, smooth colony morphotypes had more pronounced antimicrobial resistance benefit when growing as biofilm than M. abscessus showing rough colony morphotypes.

Longitudinal increase in the detection rate of Mycobacterium chimaera in heater-cooler device-derived water samples

BACKGROUND

Colonization with Mycobacterium chimaera and other non-tuberculous mycobacteria (NTM) has been reported for heater-cooler devices (HCDs) produced by several manufacturers. Up until now, exclusively LivaNova (London, UK) HCDs have been associated with M. chimaera infections after cardiac surgery. The vast majority of studies on HCD colonization were cross-sectional.

AIM

We were interested in longitudinal dynamics of mycobacterial growth in HCD water samples and analysed data of a prospective mycobacterial surveillance of five LivaNova 3T HCDs.

METHODS

Five LivaNova HCDs were subjected to prospective mycobacterial surveillance. For each HCD and the total of HCDs, results of mycobacterial detection were analyzed. Logistic regression was applied to model the association between growth of any NTM or M. chimaera and duration of HCD use.

RESULTS

Non-tuberculous mycobacteria were isolated in 319 (48.0%, 21 water samples grew more than one mycobacterial species) of a total of 665 water samples. The most frequently detected species were M. chimaera (N = 247/319, 77.4%), Mycobacterium gordonae (46/319, 14.4%) and Mycobacterium paragordonae (34/319, 10.7%). Detection rates increased prospectively for any NTM (odds ratio (OR) per year in use: 1.60, 95% confidence interval (CI) 1.17-2.24, P<0.001) and for M. chimaera (OR per year in use: 1.67, 95% CI 1.11-2.57, P<0.01).

CONCLUSION

Longer duration of HCD use was associated with higher detection rates for any NTM and M. chimaera, respectively.

Characterization of Biofilm Formation by Mycobacterium chimaera on Medical Device Materials

Non-tuberculous mycobacteria (NTM) are widespread in the environment and are a public health concern due to their resistance to antimicrobial agents. The colonization of surgical heater-cooler devices (HCDs) by the slow-growing NTM species Mycobacterium chimaera has recently been linked to multiple invasive infections in patients worldwide. The resistance of M. chimaera to antimicrobials may be aided by a protective biofilm matrix of extracellular polymeric substances (EPS). This study explored the hypothesis that M. chimaera can form biofilms on medically relevant materials. Several M. chimaera strains, including two HCD isolates, were used to inoculate a panel of medical device materials. M. chimaera colonization of the surfaces was monitored for 6 weeks. M. chimaera formed a robust biofilm at the air-liquid interface of borosilicate glass tubes, which increased in mass over time. M. chimaera was observed by 3D Laser Scanning Microscopy to have motility during colonization, and form biofilms on stainless steel, titanium, silicone and polystyrene surfaces during the first week of inoculation. Scanning electron microscopy (SEM) of M. chimaera biofilms after 4 weeks of inoculation showed that M. chimaera cells were enclosed entirely in extracellular material, while cryo-preserved SEM samples further revealed that an ultrastructural component of the EPS matrix was a tangled mesh of 3D fiber-like projections connecting cells. Considering that slow-growing M. chimaera typically has culture times on the order of weeks, the microscopically observed ability to rapidly colonize stainless steel and titanium surfaces in as little as 24 h after inoculation is uncharacteristic. The insights that this study provides into M. chimaera colonization and biofilm formation of medical device materials are a significant advance in our fundamental understanding of M. chimaera surface interactions and have important implications for research into novel antimicrobial materials, designs and other approaches to help reduce the risk of infection.

Influence of climate variables on the rising incidence of nontuberculous mycobacterial (NTM) infections in Queensland, Australia 2001-2016

International reports indicate a rising incidence of nontuberculous mycobacterial (NTM) disease. Many infectious diseases have seasonal variation in incidence, and major weather events and climate change have been implicated. The aim of this study was to explore the relationship between climate variables and NTM incident cases in Queensland, Australia.

METHODS

NTM data were obtained from the Queensland notifiable conditions database for the period 2001-2016. Rainfall and temperature data were obtained from the Australian Bureau of Meteorology. Poisson regression models were used to assess notification rates (incidence cases per 100,000 population) over time and to estimate incidence rate ratios (IRR). Cross correlation coefficients were used to examine the relationship between rainfall and temperature data and NTM incidence over time in each Hospital and Health Service (HHS).

RESULTS

12,219 NTM cases were reported. The most common species was M. intracellulare (39.1%), followed by M. avium (9.8%), M abscessus (8.5%), M. fortuitum (8.3%), M. chelonae (3.3%), and M. kansasii (2.4%). The estimated incidence rate increased from 11.10 (95% CI 8.10-15.22) in 2001 to 25.88 (95%CI 21.78-30.73) per 100,000 in 2016. The estimated IRR increased for all common species, except M. kansasii. Although increased IRRs were observed for most NTM species, geospatial heterogeneity was observed. The effect of rainfall and temperature on NTM incidence differed between species and geographic regions.

CONCLUSIONS

The incidence of NTM infections increased between 2001 and 2016. Variations in temperature and rainfall may play a role in environmental exposure to some species of NTM. Spatial variation in IRR suggests that there may also be other environmental factors that influence transmission.

Real-time PCR, the best approaches for rapid testing for Mycobacterium chimaera detection in heater cooler units and extracorporeal membrane oxygenation

According to recent investigations, the risk of M. chimaera contamination of heater-cooler units (HCUs) has reached global proportions. Our aim was to field evaluate a protocol for early detection of M. chimaera contamination. We assessed the presence of viable M. chimaera in 395 water samples obtained from 48 devices (HCUs and extracorporeal membrane oxygenation) by Real Time PCR. Thirty devices were NTM positive, of which 14 were contaminated with M. chimaera. The most frequently contaminated devices were the Stockert 3T. Noteworthy, Stockert 3T devices were positive for M. chimaera. In conclusion, this study introduces novel PMA-PCR designed to specifically detect M. chimaera in HCUs and ECMO devices; this method can replace the culture method for continuous microbiological surveillance. The timely detection of M. chimaera contamination can then be used to improve effective management of the devices.

Risk Management in the New Frontier of Professional Liability for Nosocomial Infection: Review of the Literature on Mycobacterium Chimaera

Background: Mycobacterium chimaera (MC) is of recent origin and belongs to the large family of non-tuberculous mycobacteria. In recent years, it has shown a high infectious capacity via the aerosol produced by operating room equipment, such as heater–cooler units (HCU). The infection has a long latent period and high mortality rate. Genetic and epidemiological studies have shown that there is a clear link between the infection and a specific HCU model manufactured by LivaNova/Sorin. There is, therefore, a strong possibility that contamination occurs during device construction. The objective of this article is to describe the characteristics of this particular infection in view of the medico–legal implications on professional liability, specifically focusing on current evidence regarding contamination prevention. Methods: we have analyzed the clinical characteristics and data from the autopsic investigations performed on a patient who died as a result of MC infection, in addition to analyzing all pertinent recommendation documents available internationally. We searched for all articles in the literature available on MEDLINE between 1995 and 30 July 2020, using the search words “Mycobacterium chimaera”. We then analyzed those articles and reported only those that provide useful information regarding prevention techniques for containing dissemination and contamination. Results: the literature review produced 169 results that highlight the need to develop systems to mitigate and eliminate the risk of MC infection in operating rooms such as physical containment measures, e.g. device replacement, use of safe water, providing patients with information, and training healthcare professionals. Conclusions: from a medico–legal viewpoint, this particular situation represents a new frontier of professional liability, which includes manufacturers of electromedical equipment. In order to comprehend the true extent of this silent global epidemic, the development of an organic, preventative monitoring system is essential.

Successful termination of an outbreak of Mycobacterium chimaera infections associated with contaminated heater-cooler devices

The global outbreak of invasive Mycobacterium chimaera infections associated with heater-cooler devices (HCDs) presented several important and unique challenges. To mitigate the risk of infection, we removed the HCDs from operating rooms (ORs) at our hospital and since that time (4.5 years ago) we have had no new cases.

Mycobacterium chimaera in heater-cooler devices: an experience in a tertiary hospital in Spain

The aim of the study was to describe the Mycobacterium chimaera contamination in heater–cooler devices after the application of a protocol of cleaning and disinfection in a tertiary hospital. It was an observational study at the La Paz-Cantoblanco-Carlos III University Hospital, Madrid, Spain. Seven heater–cooler devices are used in our hospital: five 3T Sorin (LivaNova) and two Maquet. We followed the manufacturers' instructions for cleaning and disinfection of the different heater–cooler devices. Environmental testing was developed monthly from January 2017 to July 2019. Samples were obtained from both cardioplegia and patient circuits and before and after the disinfection process and were cultured in appropriate media for non-tuberculous mycobacteria and heterotrophic bacteria (coliforms and Pseudomonas aeruginosa). A total of 320 samples were taken. Mycobacterium chimaera grew in four water samples (1.25%) from three different heater–cooler devices, with two positive results occurring after disinfection. The heterotrophic bacteria Delftia acidovorans and Stenotrophomonas maltophilia were also found. There has not been a case of M. chimaera infection in patients after cardiac surgery in our hospital. In March 2019, we decided to move the heater–cooler device outside the operating room. Mycobacterium chimaera contamination is not always eradicated by disinfection processes. We believe that placing 3T heater–cooler devices outside the operating room is the best option in preventing M. chimaera infection during cardiac surgery.

Failure to eradicate non-tuberculous mycobacteria upon disinfection of heater-cooler units: results of a microbiological investigation in northwestern Italy

BACKGROUND

Heater-cooler units (HCUs) used during cardiopulmonary bypass may become colonized with non-tuberculous mycobacteria (NTM), including Mycobacterium chimaera. Recently, a worldwide investigation conducted in hospitalized infected patients has detected M. chimaera in several Stockert 3T HCUs manufactured by LivaNova.

AIM

Microbiological surveillance on Stockert 3T (LivaNova) and Maquet HCU40 (Getinge) devices as well as an evaluation of the efficacy of their recommended decontamination protocols.

METHODS

A total of 308 water samples were collected from 29 HCUs: 264 samples were collected from 17 Stockert 3T HCUs and 44 samples from 12 Maquet HCU40 devices. Samples were tested for total viable counts (TVCs) at both 22 and 36°C, Pseudomonas aeruginosa, coliform bacteria, and NTM. The microbiological surveillance began in June 2017 and ran until October 2019.

FINDINGS

A total of 308 HCU water samples were analysed, 65.5% of which yielded NTM. The most frequently colonized device with NTM was the Stockert 3T (88.2%), with a frequency of positive samples of 59.5% (157/264). The Maquet HCU40 devices less frequently yielded NTM (33.3%), with a frequency of positive water samples of 13.6% (6/44). Disinfection procedures were effective in reducing TVCs of bacteria with the exception of NTM species. NTM were detected in both pre-disinfection (50.1%) and post-disinfection (55.7%) samples, and no significant association was found between disinfection and NTM results both in Stockert 3T and Maquet HCU40 devices.

CONCLUSION

This study suggests that manufacturers' procedures for disinfection are ineffective and/or inadequate. Until effective disinfection protocols become available, the only way to minimize the risk of NTM contamination is to closely monitor the water quality in the HCU, keep it as clean as possible, and treat it like any other biohazardous material.

Bacteremia in the red blood cells obtained from the cell saver in patients submitted to heart surgery

OBJECTIVE

to determine the microbiological characteristics of the red blood cells obtained with the cell saver in heart surgery patients on an extra-body circuit.

METHOD

a cross-sectional and descriptive study conducted with 358 patients scheduled for heart surgery where the saver was used. Sociodemographic variables were collected, as well as from the saver and of the microbial identification in the re-infusion bag proceeding from the cell saver. Informed consent performed.

RESULTS

of the 170 GRAM+ bacteria isolations, the most frequent species were Staphylococcus epidermidis in 69% (n=138) of the cases and Streptococcus sanguinis with a report of 10% (n=20). Significant differences were found in the Staphylococcus epidermidis strain in patients with a Body Mass Index ≥25 (p=0.002) submitted to valve surgery (p=0.001). Vancomycin was the antimicrobial which resisted the Staphylococcus epidermidis strain with a minimum inhibitory concentration of >16 µg/ml.

CONCLUSION

the microbiological characteristics of the red blood cells obtained after processing autologic blood recovered with the cell saver during heart surgery are of GRAM+ bacterial origin, the most isolated species being Staphylococcus epidermidis. Consequently, in order to reduce the presence of these GRAM+ cocci, an antibiotic should be added to the cell saver reservoir, according to a previously established protocol.

A strategy for expanding infection prevention resources to support organizational growth

BACKGROUND

The field of infection prevention is rapidly evolving and becoming increasingly complex, as resource-intensive responses to device-associated outbreaks, global epidemics, and regulatory requirements continue to grow. This increasing complexity coupled with changing health care systems present important challenges to infection prevention staffing and resources. We describe the development of a novel infection prevention and control (IPC) staffing structure that includes both infection preventionists (IPs) and role-specific support staff to meet the evolving IPC needs and challenges of an expanding health care network.

METHODS

The IPC department at Children's Hospital of Philadelphia underwent iterative modifications to its staffing structure between 2014 and 2018, including the development of revised job descriptions and promotional criteria, career ladders, and supporting roles. Data on key infection prevention activities, including rounding frequency and performance of audits and observations, growth metrics and infection data was evaluated for trends before and after departmental restructuring. An overall health care associated infection (HAI) index was calculated based on existing surveillance data and used to monitor patient outcomes over time. In addition, departmental employee engagement was assessed via a standard survey instrument to evaluate improvements in teamwork and professional growth opportunities over time.

RESULTS

Between 2014 and 2018, the number of unique job descriptions for IPs and support staff increased from 4 to 9, creating a 3-tier career ladder for IPs and increasing full time equivalents from 8.2 to 11.6. Additional support roles included a Hand Hygiene Program Manager, Infection Prevention Associates and a Clinical Practice Analyst; these roles, along with increased IP staffing, expanded the education and consultative range of the department, as measured by a 33% increase in environmental rounding and a 7-fold increase in performance of isolation audits. Team diversity also expanded, changing from a team with predominantly nursing backgrounds, to one with an equal distribution of nursing, public health, and laboratory scientists. Results from serial engagement surveys showed an increase in teamwork and professional growth by 7.4% and 5.4%, respectively. Over this time period, the total HAI index decreased by 23%, while patient days, central line days, and ventilator days increased each year, and there was a statistically significant reduction in rates of harm across 5 key HAI indicators.

CONCLUSIONS

Role diversity and varying professional backgrounds within IPC programs offer a complement of strengths and increase capacity to support patient care activities, improving patient outcomes. This strategy leads to a more cost-effective, robust IPC program that supports the growing needs and evolving challenges of the field.

Contact Effect of a Methylobacterium sp. Extract on Biofilm of a Mycobacterium chimaera Strain Isolated from a 3T Heater-Cooler System

Mycobacterium chimaera is an opportunistic slowly growing non-tuberculous mycobacteriumof increasing importance due to the outbreak of cases associated with contaminated 3T heater-cooler device (HCD) extracorporeal membrane oxygenator (ECMO). The aim of this study was to evaluate the effect of pre-treating a surface with a Methylobacterium sp. CECT 7180 extract to inhibit the M. chimaera ECMO biofilm as well as of the treatment after different dehydration times. Surface adherence, biofilm formation and treatment effect were evaluated by estimating colony-forming units (CFU) per square centimeter and characterizing the amount of covered surface area, thickness, cell viability, and presence of intrinsic autofluorescence at different times using confocal laser scanning microscopy and image analysis. We found that exposing a surface to the Methylobacterium sp. CECT 7180 extract inhibited M. chimaera ECMO biofilm development. This effect could be result of the effect of Methylobacterium proteins, such as DNaK, trigger factor, and xanthine oxidase. In conclusion, exposing a surface to the Methylobacteriumsp. extract inhibits M. chimaera ECMO biofilm development. Furthermore, this extract could be used as a pre-treatment prior to disinfection protocols for equipment contaminated with mycobacteria after dehydration for at least 96 h.

Mediastinal tissue friability-An unreported complication from Mycobacterium chimaera infection post-cardiac surgery

Mycobacterium chimaera can cause disseminated infection following cardiac surgery with cardiopulmonary bypass and contaminated heater-cooler devices. We discuss a 41-year-old man with a disseminated M. chimaera infection following surgery for a type A aortic dissection. His presentation included cachexia and dorsalgia with a work-up revealing vertebral osteomyelitis with an epidural abscess, bone marrow, and pulmonary infiltration, and fluid collection around his aortic graft. He received 1 month of antibiotics before the explantation of infected foreign material, mediastinal debridement, and aortic reconstruction. Complications included septic shock, respiratory and renal failure, mediastinitis, and four distal aortic anastomotic dehiscences from friable tissue and persistent infection.

Disseminated Mycobacterium chimaera Following Open-Heart Surgery, the Heater-Cooler Unit Worldwide Outbreak: Case Report and Minireview

Invasive cardiovascular infections by Mycobacterium chimaera associated with open-heart surgery have been reported worldwide since 2013. Here, we report a case of a 61 year old man, without any other particular medical background, who underwent cardiac surgery for replacing part of the ascending aorta by a bio-prosthetic graft. Eighteen months later, the patient was painful at the lower back with fever. A pyogenic vertebral osteomyelitis due to M. chimaera associated to graft infection was diagnosed after 6 months of sub-acute infection. The patient presented a disseminated disease with cerebral lesions, chorioretinitis, and chronic renal failure. Despite adequate antimicrobial treatment and graft explantation, the patient died after 6 years. We reviewed the literature on M. chimaera infections associated with open-heart surgery. The worldwide outbreak has been explained by airborne bioaerosol generated by the 3T heater–cooler unit (HCU) used during cardiac by-pass surgical procedures. These infections are difficult to diagnose because of a long latency period (up to several years), with no specific symptoms and a highly specialized microbiological diagnosis. The treatment is based on antibiotics and surgery. These infections are also difficult to treat, since the mortality rate is high around 50%. Prevention is necessary by modifying the use of HCUs in operating rooms.

Disinfection and cleaning of heater-cooler units: suspension- and biofilm-killing

BACKGROUND

Non-tuberculous mycobacteria (NTM) infections in cardiac surgery patients, caused by Mycobacterium chimaera or Mycobacterium abscessus, have been traced to NTM-aerosols produced by heater-cooler units of cardiopulmonary bypass equipment.

AIM

To develop a protocol to disinfect the water reservoir(s) of heater-coolers to reduce NTM numbers and thereby prevent potential NTM aerosolization; and to devise an approach to disrupt surface biofilms of heater-coolers to reduce reinoculation of the heater-cooler reservoir(s) after disinfection.

METHODS

A laboratory-scale Centers for Disease Control and Prevention bioreactor and a heater-cooler were inoculated with M. chimaera or M. abscessus to measure the ability of different disinfection protocols to reduce NTM colony-forming units in water and biofilm samples and to delay the reappearance of NTM after disinfection.

FINDINGS

The combination of an enzyme detergent cleaning agent and Clorox® were equivalent to Clorox alone in reducing M. chimaera cfu in heater-cooler water reservoir samples. However, reappearance of those bacteria was delayed by 12 weeks by the combination of enzyme detergent cleaning agent and Clorox exposure compared to Clorox disinfection alone.

CONCLUSION

A combination of an enzyme detergent and Clorox was an effective disinfection treatment and significantly delayed the reappearance of M. chimaera in the heater-cooler reservoir.

Diversity of nontuberculous mycobacteria in Heater-Cooler Devices - results from prospective surveillance

OBJECTIVE

The international outbreak of cardiac surgery-associated Mycobacterium chimaera infections was traced back to infectious aerosols originating from contaminated water reservoirs of heater-cooler devices (HCD). In general, nontuberculous mycobacteria (NTM) frequently colonize water systems and can contaminate medical devices. Data on detection of NTM other than M. chimaera in samples gathered from HCDs are scarce. The present study summarizes prospective mycobacterial surveillance of five HCDs over more than four years.

METHODS

A cohort of five, in 2014 factory-new acquired, LivaNova 3T (London, UK) HCDs were prospectively followed. Until mid-April 2014 HCDs were maintained according to the manufacturer's recommendations, subsequently according to an intensified in-house protocol including exhaust air evacuation. Mycobacterial surveillance cultures consisted of monthly water samples gathered from patient and cardioplegia circuits, as well as airflow samples.

RESULTS

Out of 441 water samples, 170 (38.6%) revealed NTM growth. The most frequently detected NTM were Mycobacterium chimaera (n=120 (67.4%)), Mycobacterium gordonae (n=35 (19.7 %)), and Mycobacterium paragordonae (n=17 (9.6%)). Growth of NTM, M. chimaera and M. paragordonae was significantly more common in water samples derived from the patient than the cardioplegia circuit of the HCD. Three (2.0%) out of 150 air samples grew NTM.

CONCLUSION

Growth of NTM in HCD water samples was frequent. Diverse NTM species were detected, with M. chimaera being most common. The majority of air samples remained negative. The relevance of NTM other than M. chimaera contaminating HCDs is poorly defined, but a recent report on a HCD-associated outbreak with Mycobacterium abscessus confirms a potential threat.

International Society of Cardiovascular Infectious Diseases Guidelines for the Diagnosis, Treatment and Prevention of Disseminated Mycobacterium chimaera Infection Following Cardiac Surgery with Cardiopulmonary Bypass

Mycobacterial infection-related morbidity and mortality in patients following cardiopulmonary bypass surgery is high and there is a growing need for a consensus-based expert opinion to provide international guidance for diagnosing, preventing and treating in these patients. In this document the International Society for Cardiovascular Infectious Diseases (ISCVID) covers aspects of prevention (field of hospital epidemiology), clinical management (infectious disease specialists, cardiac surgeons, ophthalmologists, others), laboratory diagnostics (microbiologists, molecular diagnostics), device management (perfusionists, cardiac surgeons) and public health aspects.

Mycobacterium avium in Community and Household Water, Suburban Philadelphia, Pennsylvania, USA, 2010-2012

Attention to environmental sources of Mycobacterium avium complex (MAC) infection is a vital component of disease prevention and control. We investigated MAC colonization of household plumbing in suburban Philadelphia, Pennsylvania, USA. We used variable-number tandem-repeat genotyping and whole-genome sequencing with core genome single-nucleotide variant analysis to compare M. avium from household plumbing biofilms with M. avium isolates from patient respiratory specimens. M. avium was recovered from 30 (81.1%) of 37 households, including 19 (90.5%) of 21 M. avium patient households. For 11 (52.4%) of 21 patients with M. avium disease, isolates recovered from their respiratory and household samples were of the same genotype. Within the same community, 18 (85.7%) of 21 M. avium respiratory isolates genotypically matched household plumbing isolates. Six predominant genotypes were recovered across multiple households and respiratory specimens. M. avium colonizing municipal water and household plumbing may be a substantial source of MAC pulmonary infection.

Studies of antimicrobial resistance in rare mycobacteria from a nosocomial environment

BACKGROUND

Nontuberculous mycobacteria (NTM) are ubiquitous in nature and recognized agents of opportunistic infection, which is often aggravated by their intrinsic resistance to antimicrobials, poorly defined therapeutic strategies and by the lack of new drugs. However, evaluation of their prevalence in anthropogenic environments and the associated antimicrobial resistance profiles have been neglected. In this work, we sought to determine minimal inhibitory concentrations of 25 antimicrobials against 5 NTM isolates recovered from a tertiary-care hospital surfaces. Antimicrobial susceptibilities of 5 other Corynebacterineae isolated from the same hospital were also determined for their potential clinical relevance.

RESULTS

Our phylogenetic study with each of the NTM isolates confirm they belong to Mycobacterium obuense, Mycobacterium mucogenicum and Mycobacterium paragordonae species, the latter initially misidentified as strains of M. gordonae, a species frequently isolated from patients with NTM disease in Portugal. In contrast to other strains, the M. obuense and M. mucogenicum examined here were resistant to several of the CLSI-recommended drugs, suggestive of multidrug-resistant profiles. Surprisingly, M. obuense was susceptible to vancomycin. Their genomes were sequenced allowing detection of gene erm (erythromycin resistance methylase) in M. obuense, explaining its resistance to clarithromycin. Remarkably, and unlike other strains of the genus, the Corynebacterium isolates were highly resistant to penicillin, ciprofloxacin and linezolid.

CONCLUSIONS

This study highlights the importance of implementing effective measures to screen, accurately identify and control viable NTM and closely related bacteria in hospital settings. Our report on the occurrence of rare NTM species with antibiotic susceptibility profiles that are distinct from those of the corresponding Type strains, along with unexpected resistance mechanisms detected seem to suggest that resistance may be more common than previously thought and also a potential threat to frail and otherwise vulnerable inpatients.

Mycobacterium chimaera infections following cardiac surgery in Italy: results from a National Survey Endorsed by the Italian Society of Cardiac Surgery

AIMS

A global outbreak of Mycobacterium chimaera infections following cardiac surgery and linked to contaminated heater-cooler units (HCUs) is currently ongoing. Neither the status of this outbreak in Italy nor the mitigation strategies adopted by adult cardiac surgery units (ACSUs) are currently known. In 2017, the Italian Society of Cardiac Surgery launched a national survey among the Italian ACSU to shed some light on this issue.

METHODS

In Italy, there are 90 ACSUs across 20 regions. From May to November 2017, these ACSUs were surveyed collecting data on patients diagnosed with MC infections, ACSU workload, HCU models in use and control measures adopted in the operatory room.

RESULTS

The response rate was 87.8%. The median number of cardiac procedures at each ACSU was 450/year [interquartile range (IQR) 350-650 procedures/year], and nationally, the number of procedures/year exceeded 40k. In Italy, seven patients with M. chimaera infections following cardiac procedures have been reported since 2015: all had aortic or valvular surgery as the first procedure; the median latency between the first operation and the infection was 2 years (IQR 2-3.25). Mortality for patients requiring redo cardiac surgery was 50%. M. chimaera infections risk was 0.4-1 patient every 1000 cardiac procedures. The most common HCU model in Italy is the 3T HCU (70.9%). The most common control measures adopted included implementing new HCU disinfection protocols, using sterile or filtrated water in the HCU and displacing HCU fans away from the patient: HCU replacement and microbiology testing were instead infrequent.

CONCLUSION

In Italy, the risk of contracting M. chimaera infections and the mortality reported are in line with other European countries, but significant heterogeneity exists on the mitigation strategies adopted to prevent further M. chimaera inoculations, suggesting the development of national guidelines.

Global Health Estimate of Invasive Mycobacterium chimaera Infections Associated with Heater-Cooler Devices in Cardiac Surgery

Investigations of a worldwide epidemic of invasive Mycobacterium chimaera associated with heater-cooler devices in cardiac surgery have been hampered by low clinical awareness and challenging diagnoses. Using data from Switzerland, we estimated the burden of invasive M. chimaera to be 156-282 cases/year in 10 major cardiac valve replacement market countries.

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.

Global Environmental Nontuberculous Mycobacteria and Their Contemporaneous Man-Made and Natural Niches

Seminal microbiological work of environmental nontuberculous mycobacteria (NTM) includes the discovery that NTM inhabit water distribution systems and soil, and that the species of NTM found are geographically diverse. It is likely that patients acquire their infections from repeated exposures to their environments, based on the well-accepted paradigm that water and soil bioaerosols - enriched for NTM - can be inhaled into the lungs. Support comes from reports demonstrating NTM isolated from the lungs of patients are genetically identical to NTM found in their environment. Well documented sources of NTM include peat-rich soils, natural waters, drinking water, hot water heaters, refrigerator taps, catheters, and environmental amoeba. However, NTM have also been recovered in biofilms from ice machines, heated nebulizers, and heater-cooler units, as well as seat dust from theaters, vacuum cleaners, and cobwebs. New studies on the horizon aim to significantly expand the current knowledge of environmental NTM niches in order to improve our current understanding of the specific ecological factors driving the emergence of NTM lung disease. Specifically, the Hawaiian Island environment is currently being studied as a model to identify other point sources of exposure as it is the U.S. state with the highest number of NTM lung disease cases. Because of its geographic isolation and unique ecosystem, the Hawaiian environment is being probed for correlative factors that may promote environmental NTM colonization.

Prosthetic heart valve surgery and potential risk of -developing Mycobacterium chimaera endocarditis

Public Health England (PHE) issued a guidance report on the management of Mycobacterium chimaera endocarditis following cardiac valve surgery. M chimaera is a non-tuberculous mycobacteria (NTM) belonging to mycobacterium avium complex (MAC). PHE has also recognised that M chimaera has caused severe infections in a small proportion of patients who have had cardiac surgery. Investigations in the UK and internationally have implicated contaminated heater cooler units used for cardiopulmonary bypass. Prosthetic valve endocarditis (PVE) presents as the frequent and severe form of infective endocarditis (IE). The objective of this review is to discuss the role of clinicians in assessment, treatment and reassurance of all the patients who are recalled for clinical consultation following their risk of suspected M chimaera infection after open-heart surgery.

Responding to Mycobacterium chimaera heater-cooler unit contamination: international and national intersectoral collaboration coordinated in the state of Queensland, Australia

BACKGROUND

The index case of Mycobacterium chimaera infection in a patient following open cardiac surgery in the state of Queensland, Australia prompted a centralized coordinated response to mitigate the risk.

AIM

To describe the public health response to M. chimaera contamination of heater-cooler units (HCUs) and patient infection.

METHODS

A public health sector strategy was developed with national and international consultation to respond to the threat of HCUs contaminated with M. chimaera. Data linkage of non-tuberculous mycobacterium notifications and selected procedures was undertaken where potential use of HCUs was identified through hospitalization records. Water sampling and testing protocols were standardized. Public disclosure and patient notification were undertaken.

FINDINGS

A single case of disseminated M. chimaera infection in a patient has been diagnosed to date in Queensland, Australia. Ten of 12 (83%) LivaNova Stockert 3T HCUs from five hospitals tested positive for M. chimaera. In total, 5650 patients were notified by post of their potential risk of exposure. Use of the telehealth call centre was modest. M. chimaera was also found in extracorporeal membrane oxygenation heater units produced by two other device manufacturers, four of which tested positive prior to commissioning for use.

CONCLUSIONS

Rapid international collaboration optimized the Queensland Health response to potential M. chimaera exposure during cardiac surgery. State-wide collaboration ensured a transparent, consistent approach to contacting patients and informing the public of the potential risk. A framework for ongoing risk management, clinical awareness and laboratory diagnosis was established. No further cases of M. chimaera infection have been identified in Queensland.

Sterility Duration of Preprimed Extracorporeal Membrane Oxygenation Circuits

OBJECTIVES

There is a lack of standardization and supporting data regarding the duration preassembled and preprimed extracorporeal membrane oxygenation (ECMO) circuits are expected to be sterile. Therefore, the purpose of this study was to prospectively evaluate whether preassembled and preprimed ECMO circuits could maintain sterility for a period up to 65 days.

DESIGN

Four ECMO circuits (2 neonatal/pediatric¼" and 2 adolescent/adult ⅜ ") were assembled and primed under sterile conditions and maintained at room temperature. Culture samples were obtained from each circuit and plated within 1 hour. Culture samples were obtained on day 0 when assembled and primed then every 5 days up to day 65. Samples were plated on several different media including the following: blood agar plate: trypticase soy agar with 5% sheep blood, MacConkey agar, and thioglycollate broth then incubated at 35°C for 3 days.

RESULTS

All cultures obtained from the priming solution from of the¼" and ⅜ " ECMO circuits produced no microbial or fungal growth for the 65-day study period.

CONCLUSION

These pilot data suggest preprimed ECMO circuits may maintain sterility for a period up to 65 days. Additional studies evaluating a larger number of ECMO circuits are needed to confirm these findings.

Mycobacterium chimaera Infections Associated With Contaminated Heater-Cooler Devices for Cardiac Surgery: Outbreak Management

The global outbreak of Mycobacterium chimaera infections associated with heater-cooler devices (HCDs) presents several important, unique challenges for the infection prevention community. The primary focus of this article is to assist hospitals in establishing a rapid response for identification, notification, and evaluation of exposed patients, and management of HCDs with regard to placement and containment, environmental culturing, and disinfection.

Identification of Mycobacterium chimaera in heater-cooler units in China

A global outbreak of infections due to Mycobacterium chimaera has been linked to the LivaNova (formerly Sorin) 3 T heater-cooler units (HCUs). We performed a study to investigate M. chimaera from HCUs in China. Water samples were collected from all 3 T HCUs (n = 5) at our hospital in May 2017. Mycobacteria isolates were subjected to genome sequencing using the HiSeq X10 Sequencer. Species were identified based on average nucleotide identity with M. chimaera type strain DSM 44623^T. Paired-end reads of all M. chimaera genomes were retrieved from the SRA database and, together with our isolates, were mapped against the chromosome of M. chimaera reference strain ZUERICH-1 to call SNPs. Mycobacteria grew from three HCUs manufactured in 2009 but not from the two in 2016. The three isolates were identified as M. chimaera and differed from each other by 4 to 6 SNPs, and from ZUERICH-1 by 7 to 10 SNPs. The three isolates belonged to the subgroup 1.1 and were most closely related to strains of the subgroup 1.1 from HCUs or patients in Europe, Australia/New Zealand and USA, suggesting the same common source. This is the first report of M. chimaera from HCUs in China.

Infections and outbreaks of nontuberculous mycobacteria in hospital settings

Purpose of review

Non-tuberculous mycobacterial [NTM] infections in the hospital setting are a complex and often challenging entity. The goal of this review is to discuss diagnostic and treatment strategies for established as well as emerging nosocomial NTM infections.

Recent findings

NTM outbreaks have been documented in a variety of hospital settings. Contamination of medical devices or aqueous solutions is often implicated in the spread of infection. More recently, the slow grower M. chimaera has been reported in the setting of contaminated heater-cooler devices used for cardiopulmonary bypass and extracorporeal membrane oxygenation. In addition, increases in medical tourism for cosmetic surgery have led to outbreaks of rapidly growing mycobacteria.

Summary

Diagnosis and treatment of nosocomial NTM pose many challenges for the clinician. Surgical resection or debridement as well as combination antimycobacterial therapy are a mainstay in therapeutic management. Strict infection control and prevention practices are critical to the identification and cessation of outbreaks.

Mycobacterium chimaera in heater-cooler units used during cardiac surgery - growth and decontamination

BACKGROUND

Previous studies have identified patients infected with Mycobacterium chimaera (M. chimaera) subsequent to cardiac surgery. Water tanks in heater-cooler units (HCUs) used cardiac heart surgery was traced as source. The aim was to investigate occurrence of M. chimaera and other microorganisms in HCUs and evaluate the silver-ion cleaning routine.

METHOD

Five HCUs were disinfected with silver-ions and examined for mycobacteria directly (15 min) after the disinfection procedures and later on three occasions (3, 6, 10 weeks). One HCU was selected for additional investigation of the presence of other microorganisms. In addition, tap water from five sinks in the surgical department was examined for the presence of mycobacteria and other microorganisms.

RESULTS

M. chimaera grew in all the HCU water tanks and in 35 of the 40 HCU samples. Three of the samples also contained Mycobacterium gordonae. When the selected HCU tanks were analysed directly after the disinfection procedure bacteria and fungi were found but no non-fermenting Gram-negative rods. These HCU samples contained a doubled to 3 fold amount of bacteria compared to initial tap water samples. No mycobacteria were found in any sample from the five water taps.

CONCLUSION

The silver-ion cleaning routine was insufficient and M. chimaera was found in all HCUs. However, no mycobacteria were found in any sample from the five water taps suggesting another source of colonization. It is probable that residual water and biofilm are of importance. Our results emphasize the need for improved disinfection procedures and improved construction of the HCUs.

A novel wall water system for cardiopulmonary bypass may reduce the risk of aerosolized infection

OBJECTIVE

Oxygenators for cardiopulmonary bypass require water flow for their integral heat exchanger. Heater-cooler units are nearly universally used for this requirement. Heater-cooler units pose the risk of aerosolized infection. The Centers for Disease Control and Prevention recommended discontinuing use of Stöckert 3T heater-cooler units (LivaNova PLC, London, United Kingdom) in October 2016 because of this risk. We aimed to reduce the risk of aerosolized infection posed by heater-cooler units by eliminating those devices from our operating rooms.

METHODS

The cardiac surgery division collaborated with in-house specialties to engineer a novel wall water system. The design called for service to 4 operating rooms with the actual water mixing valve in an operating room closet. Remote temperature control was mounted next to the heart-lung machine. Primary safety systems built into the water system include 5 μm filtration, pressure regulating and relief valves, flow quantifiers, limits to the hot and chilled input temperatures, and a novel bridge near the heart-lung machine that allows the perfusionist to test the system before patient use and to quickly disconnect the patient in case of system malfunction. In addition, all water line connections can be made with the tubing drained and never under pressure.

RESULTS

This novel wall water system has successfully provided heat exchanger water flow on 625 patients undergoing congenital heart surgery requiring cardiopulmonary bypass during its first 9 months of use.

CONCLUSIONS

Wall water systems are an option for oxygenator heat exchangers that allow for improved heat exchange performance while reducing the risk of heater-cooler unit-associated infection during cardiac surgery.

Response to Alert on Possible Infections with Mycobacterium chimaera From Contaminated Heater-Cooler Devices in Hospitals Participating in the Canadian Nosocomial Infection Surveillance Program (CNISP)

Canadian hospitals were made aware of the risk of Mycobacterium chimaera infection associated with heater-cooler units (HCUs) through alerts issued by the US food and Drug Administration (FDA) and the US Centers for Disease Control and Prevention (CDC). In response, most hospitals conducted retrospective reviews for infections, informed exposed patients, and initiated a requirement for informed consent with HCU use. Infect Control Hosp Epidemiol 2018;39:482-484.

Haematological alterations in the cardiac patient after use of an autotransfusion system

OBJECTIVE

There are studies that declare blood recovered with the autotransfusion system that is potentially heparinised and mixed with other drugs, can cause haematological alterations in the patient, according to existing evidence. The proposal was to compare the haematological values of the patients before reinfusing red blood cells from the cell saver and 12h after reinfusion.

MATERIAL AND METHODS

Observational analytical study of 479 patients who underwent cardiac surgery where the cell saver was used. Haematological variables were collected before reinfusion and 12h after reinfusion.

RESULTS

Statistically significant haematological values before reinfusion and 12h after reinfusion were: haemoglobin (9.5 to 12.5g/dL), haematocrit (26 to 38%), platelets (214.2 to 164.210^3/μL), total proteins (7.6 to 5.1g/dL), PCR (8.5 to 22.1mg/L) and D-dimer (493.3 to 875.5μg/L) with P<.05.

CONCLUSIONS

With the use of the cell saver an increase was observed of haemoglobin, haematocrit, PCR and D-dimer values together with a decrease in platelet and total protein numbers.

Mycobacterium chimaera infections associated with heater-cooler units in cardiac surgery

PURPOSE OF REVIEW

Mycobacterium chimaera infections following cardiac surgery have been reported from an increasing number of countries. These infections are characterized by a poor prognosis with a case fatality rate around 50% despite treatment. Since the first description in 2013, our understanding has grown steadily. Several outbreak investigations, case series, and experiments with heater-cooler units (HCUs) have been published. This review summarizes the current knowledge.

RECENT FINDINGS

M. chimaera transmission occurs during cardiopulmonary bypass via bioaerosols emitted from contaminated HCU water systems. Manifestations of M. chimaera infection comprise endocarditis, vascular graft infections, surgical site infections, and dissemination. So far, all cases were exposed to a single HCU brand. Samples from the manufacturing site as well as clonality of M. chimaera strains isolated from HCUs and patients suggest a contamination already at time of delivery representing the main source for the outbreak. Nevertheless, HCU contamination in hospitals cannot be excluded.

SUMMARY

Improved awareness of physicians of M. chimaera infection is crucial to prompt adequate diagnostic workup in patients that have been exposed to HCU presenting with compatible symptoms. For risk mitigation, strict separation between the air volume in contact with HCUs and critical clinical areas such as operating rooms is essential.

Detection limit of Mycobacterium chimaera in water samples for monitoring medical device safety: insights from a pilot experimental series

BACKGROUND

A growing number of Mycobacterium chimaera infections after cardiosurgery have been reported by several countries. These potentially fatal infections were traced back to contaminated heater-cooler devices (HCDs), which use water as a heat transfer medium. Aerosolization of water contaminated with M. chimaera from HCDs enables airborne transmission to patients undergoing open chest surgery. Infection control teams test HCD water samples for mycobacterial growth to guide preventive measures. The detection limit of M. chimaera in water samples, however, has not previously been investigated.

AIM

To determine the detection limit of M. chimaera in water samples using laboratory-based serial dilution tests.

METHODS

An M. chimaera strain representative of the international cardiosurgery-associated M. chimaera outbreak was used to generate a logarithmic dilution series. Two different water volumes, 50 and 1000mL, were inoculated, and, after identical processing (centrifugation, decantation, and decontamination), seeded on mycobacteria growth indicator tube (MGIT) and Middlebrook 7H11 solid media.

FINDINGS

MGIT consistently showed a lower detection limit than 7H11 solid media, corresponding to a detection limit of ≥1.44 × 10⁴cfu/mL for 50mL and ≥2.4cfu/mL for 1000mL water samples. Solid media failed to detect M. chimaera in 50mL water samples.

CONCLUSION

Depending on water volume and culture method, major differences exist in the detection limit of M. chimaera. In terms of sensitivity, 1000mL water samples in MGIT media performed best. Our results have important implications for infection prevention and control strategies in mitigation of the M. chimaera outbreak and healthcare water safety in general.

Minimising the risk of Mycobacterium chimaera infection during cardiopulmonary bypass by the removal of heater-cooler units from the operating room

Introduction:

Mycobacterium chimaera ( M. chimaera) is a recently characterised bacterium that can cause life-threatening infections in small numbers of patients who undergo cardiopulmonary bypass during cardiac surgery. The likely mode of transmission is thought to occur through aerosolisation from contaminated water reservoirs. The airborne bacteria then contaminate the surgical field, leading to an infection months or even years later. The preferred practical solution to disrupt the transmission of these airborne bacteria to the patient is to remove the heater-cooler units (HCUs) from the operating room (OR). We describe a process of achieving this in order to provide information to guide other institutions who wish to do a similar thing.

Methods:

A multidisciplinary team was assembled to work on the project. The planning phase involved trialling different OR layouts and simulating the alterations in the HCU circuit function. The changes to the OR were made over a weekend to minimise disruption to the operating schedule.

Results:

The HCU was moved to the dirty utility room adjacent to the OR. Standard operating procedures (SOP) and risk assessments were made to enable this to be used for a dual purpose. One of the ORs was reconfigured to allow the cardiopulmonary bypass machine to be located close to the HCU in the dirty utility room. The total cost of the alterations was £6,158. Although we have provided a physical barrier to interrupt patient exposure to aerosolised M. chimaera from HCUs, we continue to perform cultures and decontamination as per the national recommendations. The SOP was designed to be auditable to ensure compliance with the protocols.

Conclusions:

We show a method by which the HCU can be removed from the OR in a relatively low-cost, straightforward and practical manner.

Epidemiologic Review of Veterans Health Administration Patients with Isolation of Nontuberculous Mycobacteria after Cardiopulmonary Bypass Procedures

We evaluated the isolation of postoperative nontuberculous mycobacteria (NTM) associated with heater-cooler devices (HCDs) used during cardiopulmonary bypass (CPB) surgery in the Veterans Health Administration from January 1, 2010, to December 31, 2016. In more than 38,000 CPB procedures, NTM was isolated in 111 patients; 1 Mycobacterium chimaera mediastinitis case and 1 respiratory isolate were found.

Infect Control Hosp Epidemiol 2017;38:1103–1106

Mycobacterium chimaera - a new threat for cardiac surgical patients?

An outbreak of invasive Mycobacterium chimaera infections associated with "heater-cooler" devices in patients treated with cardiac surgery has been described worldwide. The authors summarize the current state of knowledge regarding the epidemiology, diagnostics, treatment, and prevention of Mycobacterium chimaera infections in patients after cardiothoracic surgery.

Mycobacterium chimaera infections in post-operative patients exposed to heater-cooler devices: An overview

A multi-country outbreak of Mycobacterium chimaera infection associated with contaminated heater-cooler devices (HCDs) has been reported, with more than 70 cases in Europe and the United States and two cases in Canada to date. The epidemiological and microbiological characteristics of this outbreak provide evidence for common-source transmission of M. chimaera from the exhaust air of intrinsically contaminated HCDs to patients during cardiac surgery. To date, all reported cases have been associated with Stöckert 3T HCDs manufactured at one plant by LivaNova prior to September 2014. Implantation of prosthetic material increases the risk of infection. Infections usually present as prosthetic valve endocarditis, vascular graft infection or disseminated infection. Reported mortality rates have varied, but were often over 40%. Several measures are recommended to facilitate case-finding and mitigate risk of exposure. The feasibility of some risk mitigation measures and their effectiveness in reducing the risk of exposure are yet to be determined. Until HCDs are redesigned in a manner that prevents water contamination and aerosolization, separating the HCD exhaust air from the operating room air during surgery may be the most effective risk mitigation strategy. However, possible unintended consequences of this approach should be considered. This overview summarizes findings from peer-reviewed and other relevant national documents on key features of the outbreak, including the source, identified risk factors for infection, signs and symptoms of infection, burden of disease, risk mitigation measures, management challenges and knowledge gaps.

Microbiological problems and biofilms associated with Mycobacterium chimaera in heater-cooler units used for cardiopulmonary bypass

The role of heater-cooler units (HCUs) in the transmission of Mycobacterium chimaera during open heart surgery has been recognized since 2013. Subsequent investigations uncovered a remarkable global outbreak reflecting the wide distribution of implicated devices. HCUs are an essential component of cardiopulmonary bypass operations and their withdrawal would severely affect capacity for life-saving cardiac surgery. However, studies have demonstrated that many HCUs are contaminated with a wide range of micro-organisms, including M. chimaera and complex biofilms. Whole genome sequencing of M. chimaera isolates recovered from one manufacturer's HCUs, worldwide, has demonstrated a high level of genetic similarity, for which the most plausible hypothesis is a point source contamination of the devices. Dissemination of bioaerosols through breaches in the HCU water tanks is the most likely route of transmission and airborne bacteria have been shown to have reached the surgical field even with the use of ultraclean theatre ventilation. Controlling the microbiological quality of the water circulating in HCUs and reducing biofilm formation has been a major challenge for many hospitals. However, enhanced decontamination strategies have been recommended by manufacturers, and, although they are not always effective in eradicating M. chimaera from HCUs, UK hospitals have not reported any new cases of M. chimaera infection since implementing these mitigation strategies. Water safety groups in hospitals should be aware that water in medical devices such as HCUs may act as a vector in the transmission of potentially fatal water-borne infections.

Clinical implications of Mycobacterium chimaera detection in thermoregulatory devices used for extracorporeal membrane oxygenation (ECMO), Germany, 2015 to 2016

Mycobacterium chimaera, a non-tuberculous mycobacterium, was recently identified as causative agent of deep-seated infections in patients who had previously undergone open-chest cardiac surgery. Outbreak investigations suggested an aerosol-borne pathogen transmission originating from water contained in heater-cooler units (HCUs) used during cardiac surgery. Similar thermoregulatory devices are used for extracorporeal membrane oxygenation (ECMO) and M. chimaera might also be detectable in ECMO treatment settings. We performed a prospective microbiological study investigating the occurrence of M. chimaera in water from ECMO systems and in environmental samples, and a retrospective clinical review of possible ECMO-related mycobacterial infections among patients in a pneumological intensive care unit. We detected M. chimaera in 9 of 18 water samples from 10 different thermoregulatory ECMO devices; no mycobacteria were found in the nine room air samples and other environmental samples. Among 118 ECMO patients, 76 had bronchial specimens analysed for mycobacteria and M. chimaera was found in three individuals without signs of mycobacterial infection at the time of sampling. We conclude that M. chimaera can be detected in water samples from ECMO-associated thermoregulatory devices and might potentially pose patients at risk of infection. Further research is warranted to elucidate the clinical significance of M. chimaera in ECMO treatment settings.