Heater-cooler Units Research Articles

Global outbreak of severe Mycobacterium chimaera disease after cardiac surgery: a molecular epidemiological study

Since 2013, over 100 cases of Mycobacterium chimaera prosthetic valve endocarditis and disseminated disease were notified in Europe and the USA, linked to contaminated heater-cooler units (HCUs) used during cardiac surgery. We did a molecular epidemiological investigation to establish the source of these patients' disease. We included 24 M chimaera isolates from 21 cardiac surgery-related patients in Switzerland, Germany, the Netherlands, and the UK, 218 M chimaera isolates from various types of HCUs in hospitals, from LivaNova (formerly Sorin; London, UK) and Maquet (Rastatt, Germany) brand HCU production sites, and unrelated environmental sources and patients, as well as eight Mycobacterium intracellulare isolates. Isolates were analysed by next-generation whole-genome sequencing using Illumina and Pacific Biosciences technologies, and compared with published M chimaera genomes. Phylogenetic analysis based on whole-genome sequencing of 250 isolates revealed two major M chimaera groups. Cardiac surgery-related patient isolates were all classified into group 1, in which all, except one, formed a distinct subgroup. This subgroup also comprised isolates from 11 cardiac surgery-related patients reported from the USA, most isolates from LivaNova HCUs, and one from their production site. Isolates from other HCUs and unrelated patients were more widely distributed in the phylogenetic tree. HCU contamination with M chimaera at the LivaNova factory seems a likely source for cardiothoracic surgery-related severe M chimaera infections diagnosed in Switzerland, Germany, the Netherlands, the UK, the USA, and Australia. Protective measures and heightened clinician awareness are essential to guarantee patient safety. Partly funded by the EU Horizon 2020 programme, its FP7 programme, the German Center for Infection Research (DZIF), the Swiss National Science Foundation, the Swiss Federal Office of Public Health, and National Institute of Health Research Oxford Health Protection Research Units on Healthcare Associated Infection and Antimicrobial Resistance.

Mycobacterium chimaera Isolates from Heater–Cooler Units, United Kingdom

<i>Mycobacterium chimaera</i> Isolates from Heater–Cooler Units, United Kingdom

A Year in the Life of a Contaminated Heater-Cooler Unit With Mycobacterium chimaera?

OBJECTIVE Heater-cooler units (HCUs) have been shown to be a source of Mycobacterium chimaera infections. For the past year, weekly water samples have been taken from HCUs used at University Hospitals Birmingham (UHB) NHS Foundation Trust. We report the microbial contamination of the HCUs over a year detailing the decontamination regimes applied at UHB to reduce the microbial load. DESIGN Observational study SETTING UHB is a tertiary referral teaching hospital in Birmingham, United Kingdom, that provides clinical services to nearly 1 million patients every year. The UHB Cardiac department is one of the largest in the United Kingdom and provides treatment for adult patients with a wide range of cardiac diseases. METHODS Water samples taken from HCUs used at UHB for cardiopulmonary bypass surgery were sampled over a year to determine the number of microorganisms by membrane filtration. Various decontamination processes were employed throughout the year. RESULTS Varying total viable counts containing a wide variety of microorganisms were obtained from water inside the HCUs. No M. chimaera were isolated after replacement of the HCU internal tubing. Stringent decontamination regimes resulted in degradation of the HCUs and increased TVCs after several months. CONCLUSION More work is required to ensure effective decontamination processes to reduce the microbial load within the HCUs. Our studies indicate that weekly water sampling for TVC will be required indefinitely to monitor the water quality in these units as well as regular replacement of the tubing to control the build-up of biofilm. Infect Control Hosp Epidemiol 2017;38:705-711.

Heater-cooler unit contamination with Mycobacterium chimaera - potential harmful risks for cardiac surgery patients.

Heater-cooler unit contamination with Mycobacterium chimaera - potential harmful risks for cardiac surgery patients.

Mycobacterium chimaera in Heater–Cooler Units in Denmark Related to Isolates from the United States and United Kingdom

Mycobacterium chimaera was present at high rates (>80%) in heater–cooler units (HCUs) from all 5 thoracic surgery departments in Denmark. Isolates were clonal to HCU-associated isolates from the United States (including some from patients) and United Kingdom. However, M. chimaera from 2 brands of HCU were genetically distinct.

Mycobacterium chimaera: Coming out of Nowhere to Dominate 2016 Infection Prevention Discussions

Mycobacterium chimaera is a bacterium of the 21st century. The organism was named in 2004 when molecular assays showed it to belong to the Mycobacterium avium complex. More specifically, it was found to be a close relative of Mycobacterium intracellulare. Merely a decade later, M. chimaera turned out to be the cause of infections associated with heater-cooler units used during open-heart surgery. There are still less than 100 confirmed cases worldwide, but the mycobacterial species has captured the attention of patients and caregivers alike because many of these infections are manifested months to years following surgery. No one currently knows the number of people who have been infected with M. chimaera or how many will ultimately be affected.

Mycobacterium chimaera and cardiac surgery.

There is an ongoing investigation into infections with non-tuberculous mycobacteria associated with contaminated heater-cooler units used in cardiac surgery. The overall risk is low, but surgical site and disseminated infections have been reported, including one possible case in Australia, mainly with surgery involving implantation of prosthetic material. Mycobacterium chimaera infection should be considered in patients who have previously undergone surgery with cardiopulmonary bypass and who present with cardiac or disseminated infection or sternal wound infection unresponsive to standard antibiotic therapy. Where cases are suspected, patients should be investigated and managed in consultation with an infectious diseases physician and/or clinical microbiologist. If cases are confirmed or heater-cooler devices are found to be contaminated, details should be reported to the hospital infection control team, the jurisdictional health department, the Therapeutic Goods Administration and the Australian distributor of the affected heater-cooler unit(s). Measures to manage risk should include communicating with relevant hospital departments, ensuring that the manufacturer's updated instructions for use are followed, regular testing of machines, and reviewing the location of machines when in use.

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

Nontuberculous mycobacteria (NTM) commonly colonize municipal water supplies and cause healthcare-associated outbreaks. We investigated a biphasic outbreak of Mycobacterium abscessus at a tertiary care hospital. Case patients had recent hospital exposure and laboratory-confirmed colonization or infection with M. abscessus from January 2013 through December 2015. We conducted a multidisciplinary epidemiologic, field, and laboratory investigation. The incidence rate of M. abscessus increased from 0.7 cases per 10000 patient-days during the baseline period (January 2013-July 2013) to 3.0 cases per 10000 patient-days during phase 1 of the outbreak (August 2013-May 2014) (incidence rate ratio, 4.6 [95% confidence interval, 2.3-8.8]; P < .001). Thirty-six of 71 (51%) phase 1 cases were lung transplant patients with positive respiratory cultures. We eliminated tap water exposure to the aerodigestive tract among high-risk patients, and the incidence rate decreased to baseline. Twelve of 24 (50%) phase 2 (December 2014-June 2015) cases occurred in cardiac surgery patients with invasive infections. Phase 2 resolved after we implemented an intensified disinfection protocol and used sterile water for heater-cooler units of cardiopulmonary bypass machines. Molecular fingerprinting of clinical isolates identified 2 clonal strains of M. abscessus; 1 clone was isolated from water sources at a new hospital addition. We made several water engineering interventions to improve water flow and increase disinfectant levels. We investigated and mitigated a 2-phase clonal outbreak of M. abscessus linked to hospital tap water. Healthcare facilities with endemic NTM should consider similar tap water avoidance and engineering strategies to decrease risk of NTM infection.

Interim laboratory testing guidelines for the detection of non-tuberculous Mycobacterium (NTM) infections in post-operative patients exposed to heater-cooler units

Interim laboratory testing guidelines for the detection of non-tuberculous Mycobacterium (NTM) infections in post-operative patients exposed to heater-cooler units

Interim laboratory testing guidance for the detection of non-tuberculous Mycobacterium (NTM) infections in post-operative patients exposed to heater-cooler units.

The advice contained in this document should be read in conjunction with relevant federal, provincial, territorial and local legislation, regulations, and policies. Recommended measures should not be regarded as rigid standards, but principles and recommendations to inform the development of guidance. This advice is based on currently available scientific evidence and adopts a precautionary approach where the evidence is lacking or inconclusive. It was approved for publication on December 5, 2016. It is subject to review and change as new information becomes available. The main changes to this version include additions to: Case load reported to date, Sarcoidosis-like disease as an Indicator, Whole Genome Sequencing effort, links to Provincial and Territorial Lab Services and Health Canada reporting.

アデノシン三リン酸測定を用いた冷温水槽の循環水の腐敗評価

アデノシン三リン酸測定を用いた冷温水槽の循環水の腐敗評価

Healthcare-associated mycobacterium chimaera transmission and infection prevention challenges: Role of heater-cooler units as a water source in cardiac surgery

Healthcare-associated mycobacterium chimaera transmission and infection prevention challenges: Role of heater-cooler units as a water source in cardiac surgery

Mycobacterium infection from a cardiopulmonary bypass heater-cooler unit in a patient with steroid-induced immunosuppression

To present a case of mycobacterium infection transmitted through a heater-cooler unit during cardiac bypass surgery.A 63-yr-old woman with a past medical history of aortic coarctation repair in 1963 and a mechanical aortic valve replacement in 2010 was prescribed antibiotics and steroids at an outpatient care facility in September 2015 for symptoms of an upper respiratory tract infection. Four months later, she developed malaise and intermittent fever with anemia and acute kidney dysfunction. Extensive evaluation revealed negative blood cultures but was suggestive of amyloidosis. The patient was therefore started on systemic steroids prior to being referred to us.At our institution, transesophageal echocardiography and cardiac magnetic resonance imaging revealed a normal mechanical aortic prosthesis with an aortic root abscess. The patient was started on empiric antibiotics for endocarditis. Renal biopsy revealed interstitial nephritis with one granuloma for which she was again started on high-dose steroids. The patient continued to deteriorate, with worsening renal function and pancytopenia that required daily red blood cell and platelet transfusions.Three weeks into this hospitalization, her blood cultures were reported to be positive for Mycobacterium chimera, and she was started on a four-drug regimen of rifampin, rifabutin, ethambutol, and clarithromycin, with dramatic clinical improvement.Heater-cooler units manufactured by LivaNova prior to September 2014 and used during cardiopulmonary bypass have been linked to M. chimera, which causes a latent infection that may be activated and become disseminated in cases of immunosuppression related to steroid use.

Insidious Risk of Severe Mycobacterium chimaera Infection in Cardiac Surgery Patients.

An urgent UK investigation was launched to assess risk of invasive Mycobacterium chimaera infection in cardiothoracic surgery and a possible association with cardiopulmonary bypass heater-cooler units following alerts in Switzerland and The Netherlands. Parallel investigations were pursued: (1) identification of cardiopulmonary bypass-associated M. chimaera infection through national laboratory and hospital admissions data linkage; (2) cohort study to assess patient risk; (3) microbiological and aerobiological investigations of heater-coolers in situ and under controlled laboratory conditions; and (4) whole-genome sequencing of clinical and environmental isolates. Eighteen probable cases of cardiopulmonary bypass-associated M. chimaera infection were identified; all except one occurred in adults. Patients had undergone valve replacement in 11 hospitals between 2007 and 2015, a median of 19 months prior to onset (range, 3 months to 5 years). Risk to patients increased after 2010 from <0.2 to 1.65 per 10000 person-years in 2013, a 9-fold rise for infections within 2 years of surgery (rate ratio, 9.08 [95% CI, 1.81-87.76]). Endocarditis was the most common presentation (n = 11). To date, 9 patients have died. Investigations identified aerosol release through breaches in heater-cooler tanks. Mycobacterium chimaera and other pathogens were recovered from water and air samples. Phylogenetic analysis found close clustering of strains from probable cases. We identified low but escalating risk of severe M. chimaera infection associated with heater-coolers with cases in a quarter of cardiothoracic centers. Our investigations strengthen etiological evidence for the role of heater-coolers in transmission and raise the possibility of an ongoing, international point-source outbreak. Active management of heater-coolers and heightened clinical awareness are imperative given the consequences of infection.

Mycobacterial infections due to contaminated heater cooler units used in cardiac bypass: An approach for infection control practitioners

Abstract Mycobacterium chimaera infection in patients who have had cardiac bypass surgery has recently been associated with contamination of water in heater cooler units. Those responsible for infection prevention and control programs face the challenge of responding to this rare but potentially life-threatening and avoidable healthcare-associated infection. Infection control professionals need to be aware of this issue and take an active role in formulating hospital responses. Policies should be rational and appropriate to the level of risk, should minimise service disruption and costs, and recognise that evidence about risk mitigation measures is still emerging. This paper provides background information to the topic and proposes a risk management based approach to heater cooler units in hospitals that perform cardiac bypass surgery, so that infection control professionals can develop a local, tailored response.

Mycobacterium chimaera colonisation of heater-cooler units (HCU) in Western Australia, 2015: investigation of possible iatrogenic infection using whole genome sequencing.

Following the reported link between heater–cooler unit (HCU) colonisation with Mycobacterium chimaera and endocarditis, mycobacterial sampling of all HCUs in use in Western Australia was initiated from August 2015, revealing M. chimaera colonisation in 10 of 15 HCUs. After M. chimaera was isolated from a pleural biopsy from a cardiothoracic patient who may have been exposed to a colonised HCU, a whole genome sequencing investigation was performed involving 65 specimens from 15 HCUs across five hospitals to assess if this infection was related to the HCU. Genetic relatedness was found between the 10 HCU M. chimaera isolates from four hospitals. However the M. chimaera isolate from the cardiothoracic patient was not genetically related to the HCU M. chimaera isolates from that hospital, nor to the other HCU isolates, indicating that the HCUs were not the source of the infection in this patient.

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.

Reemergence ofMycobacterium chimaerain Heater–Cooler Units despite Intensified Cleaning and Disinfection Protocol

Invasive Mycobacterium chimaera infections after open-heart surgery have been reported internationally. These devastating infections result from aerosols generated by contaminated heater–cooler units used with extracorporeal circulation during surgery. Despite intensified cleaning and disinfection, surveillance samples from factory-new units acquired during 2014 grew nontuberculous mycobacteria after a median of 174 days.

Transmission of Mycobacterium chimaera from Heater-Cooler Units during Cardiac Surgery despite an Ultraclean Air Ventilation System.

Heater-cooler units (HCUs) were recently identified as a source of Mycobacterium chimaera causing surgical site infections. We investigated transmission of this bacterium from HCUs to the surgical field by using a thermic anemometer and particle counter, videotape of an operating room equipped with an ultraclean laminar airflow ventilation system, and bacterial culture sedimentation plates in a nonventilated room. Smoke from the HCU reached the surgical field in 23 s by merging with ultraclean air. The HCU produced on average 5.2, 139, and 14.8 particles/min in the surgical field at positions Off, On/oriented toward, and On/oriented away, respectively. Culture plates were positive for M. chimaera <5 m from the HCU in the test room. These experiments confirm airborne transmission of M. chimaera aerosols from a contaminated HCU to an open surgical field despite ultraclean air ventilation. Efforts to mitigate infectious risks during surgery should consider contamination from water sources and airflow-generating devices.

Contamination during production of heater-cooler units by Mycobacterium chimaera potential cause for invasive cardiovascular infections: results of an outbreak investigation in Germany, April 2015 to February 2016

Invasive infections with Mycobacterium chimaera were reported in patients with previous open chest surgery and exposure to contaminated heater-cooler units (HCUs). We present results of the surveillance of clinical cases and of contaminated HCUs as well as environmental investigations in Germany up until February 2016. Clinical infections occurred in five male German cases over 50 years of age (range 53-80). Cases had been exposed to HCUs from one single manufacturer during open chest surgery up to five years prior to onset of symptoms. During environmental investigations, M. chimaera was detected in samples from used HCUs from three different countries and samples from new HCUs as well as in the environment at the manufacturing site of one manufacturer in Germany. Our investigation suggests that at least some of the M. chimaera infections may have been caused by contamination of HCUs at manufacturing site. We recommend that until sustainable measures for safe use of HCUs in operation theatres are implemented, users continue to adhere to instructions for use of HCUs and Field Safety Notices issued by the manufacturer, implement local monitoring for bacterial contamination and continuously check the websites of national and European authorities for current recommendations for the safe operation of HCUs.