Cluster of invasive Mycobacteria chimaera infections following cardiac surgery demonstrating novel clinical features and risks of aortic valve replacement

Effects of staged rehabilitation training on inflammatory factor levels and red blood cell distribution width followingcardiac valve replacement

BACKGROUND

The current study was conducted aimed atexploring the effects of staged rehabilitation training on the levels of inflammatory factors and red blood cell distribution in patients who underwent cardiac valve replacement.

METHODS

A total of 140 patients who underwent cardiac valve replacement at The First Hospital of Hebei Medical University between April 2021 and November 2022 were included in this study. During the postoperative rehabilitation phase, the patients were randomly assigned to either the control group or the experimental group. The experimental group received staged rehabilitation training (n = 70), while the control group received conventional care and rehabilitation suggestions without specialized staged rehabilitation training (n = 70). Informed consent was obtained from all patients prior to theirinclusion in the study. Clinical data of the patients were collected andanalyzed. RDW was measured using an automated blood cell analyzer on postoperative day 1, 14, and 28. Levels ofTNF-α, IL-6 and CRP were measured using ELISA. Quality of life was evaluated usingthe WHOQOL-BREF questionnaire. The effects of postoperative rehabilitation were assessed using the 6MWD test. The occurrence of adverse events in the postoperative periodwas alsoanalyzed.

RESULTS

There were no significant differences in the general characteristics of the two groups of patients (P > 0.05). On the first day after surgery, no significant differences were seen in RDW between the two groups (P > 0.05). However, on the 14th and 28th day after surgery, the experimental group exhibited a significant reduction in RDW compared to the control group (P < 0.05). On the first day after surgery, the levels of serum TNF-α, IL-6 and CRP were comparable between the two groups (P > 0.05). However, on the 14th and the 28th after surgery, the experimental group showed evidently lower levels of TNF-α, IL-6 and CRP compared to the control group (P < 0.05). The experimental group demonstrated higher scores in the domains of physical health, psychological state, social relationships, and environment in the WHOQOL-BREF questionnaire compared to the control group (P < 0.05). Furthermore, the experimental group exhibited increased average,minimum,maximum walking distances in the6-minute walking test compared to the control group (P < 0.05). There were no significant differences in the incidence of postoperative adverse events between the two groups of patients (P > 0.05).

CONCLUSION

Staged rehabilitation training exerteda positive effect on the levels of inflammatory factors and red blood cell distribution in patients following cardiac valve replacement. This type of rehabilitation training facilitated the patient's recovery process by reducing the inflammatory response and improving the condition of red blood cells. Additionally, it enhanced the quality of life and rehabilitation outcomes for patients.

Epidemiological and Molecular Investigation of the Heater-Cooler Unit (HCU)-Related Outbreak of Invasive Mycobacterium chimaera Infection Occurred in Italy

BACKGROUND

From 2013 onwards, a large outbreak of Mycobacterium chimaera (MC) invasive infection, which was correlated with the use of contaminated heater-cooler units (HCUs) during open chest surgery, was reported from all over the world. Here, we report the results of the epidemiological and molecular investigations conducted in Italy after the alarm raised about this epidemic event.

METHODS

MC strains isolated from patients or from HCU devices were characterized by genomic sequencing and molecular epidemiological analysis.

RESULTS

Through retrospective epidemiological analysis conducted between January 2010 and December 2022, 40 possible cases of patients infected with MC were identified. Thirty-six strains isolated from these patients were analysed by whole genome sequencing (WGS) and were found to belong to the genotypes 1.1 or 1.8, which are the genotypes correlated with the outbreak. Most of the cases presented with prosthetic valve endocarditis, vascular graft infection or disseminated infection. Among the cases found, there were 21 deaths. The same analysis was carried out on HCU devices. A total of 251 HCUs were found to be contaminated by MC; genotypes 1.1 or 1.8 were identified in 28 of those HCUs.

CONCLUSIONS

To ensure patients' safety and adequate follow-up, clinicians and general practitioners were made aware of the results and public health measures, and recommendations were issued to prevent further cases in the healthcare settings. The Italian Society of Cardiac Surgery performed a national survey to assess the incidence of HCU-related MC prosthetic infections in cardiac surgery. No cases were reported after HCU replacement or structural modification and disinfection and possibly safe allocation outside surgical rooms.

Mycobacterium chimaera Outbreak Management and Outcomes at a Large Pediatric Cardiac Surgery Center

BACKGROUND

In 2012, a global outbreak of invasive Mycobacterium chimaera (M. chimaera) infection was identified in patients post-cardiopulmonary bypass (CPB) surgery. Investigations revealed the source to be heater-cooler unit (HCU) exhaust, with point-source contamination discovered at the LivaNova HCU manufacturing plant. We report our experience with affected HCUs at a high-volume pediatric cardiac surgery center in the United States.

METHODS

A multi-disciplinary task force was established for outbreak management, including removing contaminated HCUs from service. Patients identified as exposed to affected HCUs were systematically contacted. A call center was created for patient/family inquiries, and symptomatic patients were assessed using an institutional triage protocol, including lab/culture data and infectious diseases consultation.

RESULTS

CPB surgeries were performed in 4,276 patients (median age 2.1 years, range 0-48.4) between October 2010 and October 2016. Call center volume was highest in the first 6 weeks following patient notification, totaling 307 calls and yielding 70 clinical patient assessments. Presenting symptoms included fatigue (60%), fever (49%), night sweats (46%), myalgias (34%), and weight loss (24%). Among the 70 assessed patients, echocardiogram (n=30), cardiac CT (n=2), cardiac MRI (n=1), and pulmonary CT (n=1) did not reveal abnormalities suggestive of active infection. Infectious diseases consultation occurred in 23 (33%) patients. Acid fast bacilli blood cultures were obtained in 30 patients; all were negative.

CONCLUSIONS

Through a highly coordinated outreach effort, no patients have been found to have M. chimaera infection in the six years after exposure to contaminated HCUs. Ongoing vigilance for cases that may yet manifest is needed.

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.

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.

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.