Related Experiment Video
Updated: Jun 11, 2025
Assessing Bacterial Invasion of Cardiac Cells in Culture and Heart Colonization in Infected Mice Using Listeria monocytogenes
Published on: May 27, 2015
The Spread of Mycobacterium chimaera from Heater-Cooler Units and Infection Risk in Heart Surgery: Lessons from the
Anna Maria Spagnolo1, Osvalda De Giglio2, Giuseppina Caggiano2
1Department of Health Sciences, University of Genova, Via Pastore 1, 16132 Genova, Italy.
Abstract:
Mycobacterium chimaera (MC), a member of the Mycobacterium avium complex, can cause infections in patients after open-heart surgery due to contaminated heater-cooler units (HCUs). The transmission route of HCU-related MC infection is non-inhalational, and infection can occur in patients without previously known immune deficiency. Patients may develop endocarditis of the prosthetic valve, infection of the vascular graft, and/or manifestations of disseminated mycobacterial infection (splenomegaly, arthritis, hepatitis, nephritis, myocarditis, etc.). MC infections have serious outcomes (30-50% recurrence rate, 20-67% mortality rate). In 2015, an international outbreak of M. chimaera infections among patients undergoing cardiothoracic surgeries was associated with exposure to contaminated LivaNova 3T HCUs (formerly Stöckert 3T heater-cooler system, London, United Kingdom). In response to the global outbreak, many international agencies have issued directives and recommendations in order to reduce the risk of MC infection in cardiac surgery. Whole-genome sequencing (WGS) technology can be used to describe the global spread and dynamics of MC infections, to characterize local outbreaks, and also to identify sources of infection in hospital settings. In order to minimize the risk of contamination of HCUs and reduce the risk of patient infection, it is imperative that healthcare facilities establish a program of regular cleaning and disinfection maintenance procedures as well as monitoring of the water used and the air in the operating room, in accordance with the manufacturer's procedure.
Insights
Mycobacterium chimaera (MC) infections after heart surgery are linked to contaminated heater-cooler units (HCUs). Strict cleaning and monitoring of HCUs are crucial to prevent serious patient outcomes and outbreaks.
Area of Science:
- Infectious Diseases
- Microbiology
- Public Health
Background:
- Mycobacterium chimaera (MC), part of the Mycobacterium avium complex, causes severe infections in patients undergoing open-heart surgery.
- Contaminated heater-cooler units (HCUs) are a non-inhalational transmission source for MC, affecting even non-immunocompromised individuals.
- MC infections lead to significant morbidity, including prosthetic valve endocarditis and disseminated disease, with high recurrence and mortality rates.
Purpose of the Study:
- To highlight the risks associated with Mycobacterium chimaera infections originating from contaminated HCUs.
- To emphasize the importance of international recommendations and directives in mitigating MC infection risks.
- To underscore the utility of whole-genome sequencing (WGS) in tracking MC outbreaks and identifying sources.
Main Methods:
- Literature review of MC infections linked to HCUs.
- Analysis of outbreak data, including the 2015 international outbreak associated with LivaNova 3T HCUs.
- Discussion of whole-genome sequencing (WGS) applications in epidemiological surveillance.
Main Results:
- MC infections pose a serious threat post-cardiothoracic surgery, with high mortality and recurrence rates.
- Contaminated HCUs, particularly the LivaNova 3T model, have been identified as a major source of MC outbreaks.
- WGS is a valuable tool for understanding MC transmission dynamics and pinpointing infection origins.
Conclusions:
- Healthcare facilities must implement rigorous cleaning, disinfection, and monitoring protocols for HCUs.
- Adherence to manufacturer guidelines and regular maintenance are essential for preventing HCU contamination.
- Proactive surveillance and infection control measures are vital to protect patients from MC infections.
Related Concept Videos
01:25Endocarditis I: Introduction
01:26Healthcare Associated Infections I: Iatrogenic, Exogenic and Endogenic
HAIs significantly increase the cost of health care. Extended stays in healthcare institutions, increased disability, increased costs of medications, including specialized antibiotics, and prolonged recovery times add to the patient's expenses and the healthcare institution and funding bodies.
01:29Pulmonary Tuberculosis I
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...
01:20Infection
The chain begins with pathogens: bacteria, viruses, fungi, prions, or parasites such as protozoa helminths. These can be present on the skin as transient or resident flora, or they can be acquired from the environment. Identifying and treating the type of infection and...
01:21Myocarditis I: Introduction
01:22Healthcare Associated Infections II: Preventive Measures
The best practices for preventing healthcare-associated infections include hand hygiene, patient risk...