Mycobacterium Chimaera Infection Research Articles

Radiologic Manifestations of Mycobacterium chimaera Infection After Open Heart Surgery.

The objective of this study is to identify and detail the radiologic manifestations of surgical site and disseminated Mycobacterium chimaera (MC) infection. The aim is to facilitate early identification and diagnosis of MC, considering its indolent nature and the challenges involved in clinically and pathologically establishing the diagnosis. This was a retrospective cohort study reviewing computed tomography (CT), positron emission tomography (PET)/CT, and magnetic resonance imaging examinations in patients over the age of 18 years with a history of open heart surgery and a clinical or pathologic diagnosis of MC. Two radiology residents, a fellowship-trained nuclear medicine radiologist, and a fellowship-trained cardiothoracic radiologist performed consensus reads to determine the imaging findings seen in MC infection. Twenty-five patients were included. Localized, surgical site infection was more common than disseminated disease. Typical CT findings included peristernal soft tissue thickening, sinus tracts often extending to the cutaneous surface, slowly enlarging fluid collections, and sternal osteolysis. PET/CT findings demonstrated hypermetabolic activity in nearly all patients localized to sites of infection. Imaging findings for disseminated infection included hepatosplenomegaly, lymphadenopathy, involvement of the central nervous system, discitis/osteomyelitis, and distant abscesses. Imaging plays a vital role in suggesting possible surgical sites and disseminated MC infection acquired from open heart surgery. Radiologists must keep a high index of suspicion given the indolent nature and subtle imaging change over time. PET/CT is most useful in diagnosis and helps in differentiating between a sterile postoperative fluid collection or scarring and active MC infection and helps provide a target for debridement.

Endobronchial Fibroanthracosis Associated With Mycobacterium Chimaera Infection: An Exceptional Case

Endobronchial Fibroanthracosis Associated With Mycobacterium Chimaera Infection: An Exceptional Case

Mycobacterium chimaera Infections in a Unit of Cardio Surgery: Study at a General Hospital in Padua, Italy.

Mycobacterium chimaera is a slow-growing non-tuberculous mycobacterium already known for being able to colonize cardio surgery heater-cooler units (HCUs). This study aims to describe the real magnitude of the phenomenon, providing a methodological protocol and the results of a longitudinal survey. In the period 1 January 2017-23 May 2022, over 1191 samples were collected on 35 HCUs of two different manufacturers. Among them, we identified 118 (10.3%) positive results for M. chimaera. We propose our 4-year biosurveillance experience as a practical model to minimize microbiological patients' risk, suggesting the need for new procedures and interventions for a safer and more ecological cardio surgery.

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

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

Immunological and metabolic characterization of environmental Mycobacterium chimaera infection in a murine model

Mycobacterium chimaera causes pulmonary disease, but little is known of gradations in isolate virulence. Previously, 17 M. chimaera isolates were screened for survival in THP1 macrophages. “M. chimaera 1” was categorized as “more virulent” because it showed the greatest survival in macrophages, whereas “M. chimaera 2” was categorized as “less virulent” with reduced survival. Herein, we infected C3HeB/FeJ mice to compare the in vivo immune responses to M. chimaera 1 and 2. Unlike macrophages, significantly lower M. chimaera 1 counts were recovered from mouse lung tissue and BAL cells with less lung histopathologic changes compared to M. chimaera 2. Compared to M. chimaera 2, significantly more IL-1β, IL-6, and TNFα was produced early after M. chimaera 1 infection. LC-MS metabolomics analyses of BAL fluid revealed divergence in sphingolipid, phospholipid metabolism between M. chimaera 1 versus M. chimaera 2 mice. From pan-GWAS analyses, virulence and organizing DNA/molecular structure genes were associated with more virulent M. chimaera isolates. Vigorous lung-specific immune responses to M. chimaera 1 may influence effective bacterial control, but for a different isolate M. chimaera 2, subvert immune control. Continued studies of the gradations in virulence among the same NTM species will advance our understanding of NTM pathogenesis.

A single-center experience with microbiologic surveillance of LivaNova 3T heater-cooler devices (HCDs)

Background: The global outbreak of Mycobacterium chimaera infections associated with HCDs resulted in new maintenance recommendations. Since 2018, HCDs have been disinfected according to instructions for use (IFU), including twice-monthly bleach disinfection and monitoring hydrogen peroxide (H2O2) to maintain a minimum daily concentration of 100 ppm. In February 2020, the IFU added the recommendation to perform microbiologic surveillance of HCD tank water to ensure effectiveness of disinfection to levels of <1 colony forming unit per milliliter (CFU/mL) of nontuberculous mycobacterium (NTM). We report our experience with this microbiologic surveillance as well as that of culturing the HCD environment to investigate modes of transmission. Methods: In 2022, we began culturing tank water in 10 HCDs for NTM. For a subset of 6 HCDs, quantitative NTM culturing of tank water before and after bleach disinfection was done. After initial results indicated widespread-contamination of HCDs with M. chimaera, we performed fill water cultures from 5 sinks in 4 HCD maintenance rooms. We also conducted 20 two-hour NTM settle-plate cultures of a cardiac operating room (OR) at different sites both inside (n = 7) and outside (n = 3) the OR: 10 with the HCD (located outside the OR) turned off (controls) and 10 with HCD turned on (exposure). A paired t test was used to evaluate differences in mean recovery of NTM in tank water samples. Results: Cultures from 7 (70%) of 10 HCDs were positive, with a mean of 13.6 CFU/mL M. chimaera (Table 1). There was no significant difference between the 10 pairs of pre- and postdisinfection NTM cultures done according to the IFU from 6 HCDs: mean predisinfection cultures (15.5 CFU/mL) versus mean postdisinfection cultures (12 CFU/mL) (P = .90) (Table 2). For fill water, 1 of 7 sink samples in 1 of 4 rooms was positive for M. chimaera ( <1 CFU/mL) from a specimen from a fresh 0.2-µm filter that had been stored in the fill-sink splash zone. OR settle-plate cultures showed 0 (0%) of 10 control sites and 1 (10 %) of 10 exposure sites inside the OR positive for NTM, with a single CFU of M. avium–intracellulare complex. Conclusions: Our data cannot clearly refute either of 2 possible scenarios for HCD contamination: cross contamination during device maintenance versus at the point of manufacture. Despite the IFU guidance or disinfection being implemented, disinfection procedures failed to suppress NTM contamination, and tank water within most HCDs was contaminated with M. chimaera regardless of age or whether it was deep cleaned or upgraded with an aerosol containment device.Disclosures: None

Long-Term Follow-Up after Mycobacterium Chimaera Infection Following Cardiac Surgery: Single-Center Experience.

Disseminated Mycobacterium chimaera (M. chimaera) infection following cardiac surgery has been associated with a high mortality. The long-term impact of surgery and the appropriate surgical approach are still matters of debate. From 2015 to 2019, seven patients with M. chimaera infection following cardiac surgery were isolated. The median incubation time was 30 months (IQR 18-38). Echocardiography was unremarkable in three patients (43%). We decided to redo cardiac surgery in all patients and explanted all previously implanted prosthetic material. All explant cultures yielded M. chimaera. One patient (14%) died in-hospital seven months after the redo surgery. After a median follow-up of 59.6 months (IQR 39.1-69.6), we observed three infection relapses among the survivors (43%), presumably due to concomitant extracardiac infection and recurrent cardiac implant infection. M. chimaera infection following cardiac surgery is associated with a delayed and unspecific clinical presentation. Echocardiogaphy has a limited sensitivity for prosthetic valve infection with M. chimaera, and negative findings should not preclude the surgical decision. The extraction of all previously implanted material is crucial to achieving the source control, as the re-implantation of prosthetic material as well as uncontrolled extracardiac infection at the time of the redo cardiac surgery appear to be key factors for persisting/relapsing infection.

Disseminated Mycobacterium chimaera infection favoring the development of Kaposi's sarcoma: a case report.

Disseminated Mycobacterium chimaera infection is an emerging disease in people undergone to cardiothoracic surgery, which need to be suspected also with atypical presentations. We report the case of a 74-year-old man with fever of unknown origin, purple nodules on both feet and a history of open-heart surgery. Imaging investigations showed an abscess near aortic bioprosthesis but screening for endocarditis resulted negative and pyrexia did not respond to antibiotic therapy. A biopsy of cutaneous lesions showed HHV8-related Kaposi's sarcoma, so bone marrow biopsy was executed with evidence of HHV8 localization. Bone marrow and urine mycobacterial cultures resulted positive for M. chimaera and a specific antimicrobial therapy was started, with apyrexia after 7 weeks. M. chimaera infection should be always investigated as a possible etiology of fever of unknow origin in people with a history of open-heart surgical intervention, even with negative mycobacterial blood cultures. The possible role of disseminated infection in inducing immunodepression with the occurrence of other opportunistic diseases (such as Kaposi's sarcoma) cannot be excluded.

Abstract 15314: Advanced Cardiovascular Imaging for the Diagnosis of Mycobacterium Chimaera Prosthetic Valve Infective Endocarditis After Open-Heart Surgery: A Systematic Review

Introduction: Mycobacterium chimaera is an emerging pathogen, recognized to cause prosthetic valve infective endocarditis (PVIE) and disseminated infection following open-chest cardiac surgery with certain contaminated heater-cooler systems. Diagnosis is challenging and requires a very high index of suspicion. Data regarding the optimal cardiac imaging evaluation of this condition is limited. Methods: Scopus, PubMed, EMBASE, Ovid and Cochrane were searched for published articles through October 2021, using keywords “Mycobacterium chimaera”, “Prosthetic valve” and “Endocarditis”. 169 articles were found and reviewed for study eligibility. Articles were included if they consisted of Mycobacterium chimaera causing IE, with imaging modalities used to establish diagnosis Results: Thirty-three articles were included, yielding twenty-two cases of Mycobacterium chimaera PVIE. The disease manifested on average thirty months after surgery, with an average patient age of 59 years (90% male). Imaging modalities to establish the diagnosis of prosthetic valve infective endocarditis included: transthoracic echocardiogram in 5 cases, transesophageal echocardiogram (TEE) in nine cases, 18F-FDG-PET/CT in seven cases. A combination of imaging modalities with TEE and 18F-FDG-PET/CT was reported once; TTE, TEE and 18F-FDG-PET/CT was also noted in one case. Lastly there was one instance each of combined use of TTE, TEE, and one of the following: CTA, Cardiac MRI, or standard CT. Nine cases did not specify the imaging modality used to achieve diagnosis. Ten patients died. Conclusions: PVIE due to Mycobacterium chimaera infection is a rare and challenging diagnosis, which requires a high index of suspicion. Accurate diagnosis should be aided by multimodality cardiac imaging, with 18F-FDG-PET/CT being a powerful adjunct imaging modality.

Disseminated Mycobacterium chimaera infection in a patient with adult-onset immunodeficiency syndrome: case report

BackgroundPatients with adult-onset immunodeficiency syndrome due to anti-interferon-γ autoantibodies (AIGAs) are susceptible to disseminated Mycobacterium avium complex (MAC) infections. M. chimaera, a newly identified MAC species, is distinguished from the others due to the reduced virulence. Previous cases of disseminated M. chimaera infection have been linked to cardiothoracic surgery. Reports of disseminated M. chimaera in patients without a history of cardiothoracic surgery are rare.Case presentationA 57-year-old Asian man, previously healthy, presented with fever, dry cough, exertional dyspnea, and decreased appetite. The delayed resolution of pneumonia despite antibiotic treatment prompted further imaging studies and biopsies from the lung and lymph node. The fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) demonstrated intense uptake in lung consolidations and diffuse lymphadenopathy. Cultures of the specimens obtained from sputum, blood, stool, lung tissue, and lymph node grew M. chimaera. Further immunological evaluation disclosed the presence of neutralizing AIGAs, which possibly led to acquired immunodeficiency and disseminated M. chimaera infection.ConclusionsWe herein present the first case of adult-onset immunodeficiency due to AIGAs complicated with disseminated M. chimaera infection. Further immunological evaluation, including AIGAs, may be warranted in otherwise healthy patients who present with disseminated mycobacterial infection.

Pharmacologic Management of Mycobacterium chimaera Infections: A Primer for Clinicians.

Mycobacterium chimaera, a member of the Mycobacterium avium complex, can cause infections in individuals after open heart surgery due to contaminated heater-cooler units. The diagnosis can be challenging, as the incubation period can be quite variable, and symptoms are nonspecific. In addition to aggressive surgical management, combination pharmacologic therapy is the cornerstone of therapy, which should consist of a macrolide, a rifamycin, ethambutol, and amikacin. Multiple second-line agents may be utilized in the setting of intolerances or toxicities. In vitro susceptibility of these agents is similar to activity against other species in the Mycobacterium avium complex. Drug–drug interactions are frequently encountered, as many individuals have chronic medical comorbidities and are prescribed medications that interact with the first-line agents used to treat M. chimaera. Recognition of these drug–drug interactions and appropriate management are essential for optimizing treatment outcomes.

Case report of the first cured patient with Mycobacterium Chimaera infection following cardiac valve replacement in the mainland of China

BackgroundMycobacterium chimaera infections subsequent to cardiac surgery are related to contaminated heater-cooler devices, with high mortality. Nevertheless, few studies have been reported in Asia.Case presentationWe described the case of a 55-year-old man with Mycobacterium chimaera infection following cardiac surgery in the mainland of China. He was diagnosed with endocarditis caused by Mycobacterium chimaera subsequent to open heart surgery. Metagenomic next-generation sequencing (mNGS) and 16S rRNA gene PCR analysis were used to identify potential pathogens. The patient underwent redo valve replacement surgery and received combination therapy with azithromycin, ethambutol, linezolid, and amikacin. No signs of relapse were observed during the 11-month follow-up visit.ConclusionsThis is the first documented case of Mycobacterium chimaera infection following cardiac surgery in the mainland of China and the first documented transnational imported case worldwide. Moreover, mNGS is a novel diagnostic technology that can guide antimicrobial therapy prior to obtaining fluid/tissue culture results for Mycobacterium chimaera, providing a new approach for the detection of potential Mycobacterium chimaera infection.

Mycobacterium chimaera infections among cardiothoracic surgery patients associated with heater-cooler devices-Kansas and California, 2019.

In 2015, an international outbreak of Mycobacterium chimaera infections among patients undergoing cardiothoracic surgeries was associated with exposure to contaminated LivaNova 3T heater-cooler devices (HCDs). From June 2017 to October 2020, the Centers for Disease Control and Prevention was notified of 18 patients with M. chimaera infections who had undergone cardiothoracic surgeries at 2 hospitals in Kansas (14 patients) and California (4 patients); 17 had exposure to 3T HCDs. Whole-genome sequencing of the clinical and environmental isolates matched the global outbreak strain identified in 2015. Investigations were conducted at each hospital to determine the cause of ongoing infections. Investigative methods included query of microbiologic records to identify additional cases, medical chart review, observations of operating room setup, HCD use and maintenance practices, and collection of HCD and environmental samples. Onsite observations identified deviations in the positioning and maintenance of the 3T HCDs from the US Food and Drug Administration (FDA) recommendations and the manufacturer's updated cleaning and disinfection protocols. Additionally, most 3T HCDs had not undergone the recommended vacuum and sealing upgrades by the manufacturer to decrease the dispersal of M. chimaera-containing aerosols into the operating room, despite hospital requests to the manufacturer. These findings highlight the need for continued awareness of the risk of M. chimaera infections associated with 3T HCDs, even if the devices are newly manufactured. Hospitals should maintain vigilance in adhering to FDA recommendations and the manufacturer's protocols and in identifying patients with potential M. chimaera infections with exposure to these devices.

Coordinated, Collaborative Management of an Outbreak: Lessons for Maintenance of Patient Trust

One of the tenets of a successful provider-patient relationship is trust, and trust can only be maintained with bidirectional open and honest communication. This is especially true in communicating possible untoward outcomes of our surgeries. In this issue of The Annals of Thoracic Surgery, the article by Chandrasekar and colleagues1 shares the experience of one of the largest pediatric cardiac surgery centers in the United States with the outbreak of the Mycobacterium chimaera infection in cardiac surgical patients.

Long-Term Clinical and Multimodal Imaging Findings in Patients with Disseminated Mycobacterium Chimaera Infection.

Background: To analyze long-term ophthalmic clinical and multimodal imaging findings of disseminated Mycobacterium (M.) chimaera infection after cardiothoracic surgery among the Swiss Cohort. Methods: Systemic and multimodal ophthalmic imaging and clinical findings including rate of recurrence were reviewed and correlated to a previously proposed classification system of choroidal lesions and classification of ocular disease. Main Outcomes Measures: long-term clinical and multimodal ocular imaging findings of M. chimaera. Results: Twelve patients suffering from systemic infection from M. chimaera were included. Mean age at the first ophthalmic examination was 59 years (range from 48 to 66 years). Mean duration of the follow-up was 22.63 ± 17.8 months. All patients presented with bilateral chorioretinal lesions at baseline; 5 patients had additional signs, including optic disc swelling (2), choroidal neovascularization (1), retinal neovascularization (1) and cilioretinal vascular occlusion (1). Four recurrence events after discontinuation or adjustment of the antibiotic treatment were observed. Progressive choroiditis was seen in 5 patients under treatment, 4 of them deceased. Conclusions: Expertise from ophthalmologists is not only relevant but also critical for the assessment of the adverse drug effect of antimycobacterial treatment along with monitoring therapeutic response and identifying recurrences.

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

BackgroundIn 2012, a global outbreak of invasive Mycobacterium chimaera (M. chimaera) infection was identified in patients after cardiopulmonary bypass surgery. Investigations revealed the source to be heater-cooler unit (HCU) exhaust, with point-source contamination discovered at the LivaNova HCU manufacturing plant (London, UK). We report our experience with affected HCUs at a high-volume pediatric cardiac surgery center in the United States. MethodsA multidisciplinary 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 laboratory/culture data and infectious diseases consultation. ResultsCardiopulmonary bypass surgeries were performed in 4276 patients (median age: 2.1 years; range: 0-48.4 years) between October 2010 and October 2016. Call center volume was highest in the first 6 weeks after 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 computed tomography (n = 2), cardiac magnetic resonance imaging (n = 1), and pulmonary computed tomography (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. ConclusionsThrough a highly coordinated outreach effort, no patients have been found to have M. chimaera infection in the 6 years after exposure to contaminated HCUs. Ongoing vigilance for cases that may yet manifest is needed.

Updated Experience of Mycobacterium chimaera Infection: Diagnosis and Management in a Tertiary Care Center.

BackgroundDespite safety communications from the Food and Drug Administration (FDA) regarding the outbreak of Mycobacterium chimaera infections (MCIs) from contaminated heater-cooler devices, new cases continue to be identified.MethodsWe retrospectively reviewed confirmed cases of MCI that were managed at Mayo Clinic sites (Arizona, Florida, and Minnesota) from 09/2015 to 01/2021. Clinical histories including prior cardiovascular surgery were recorded. Diagnostic workup including ophthalmologic examination, imaging, and laboratory testing was reviewed. Treatment and survival outcomes on follow-up were obtained.ResultsTwelve patients with MCI were included. All patients had aortic valve or graft replacement. Five patients had their surgical procedures following the 10/15/2015 FDA safety communication. The mean time from surgery to symptom onset (range) was 32 (13–73) months. Ten of 11 patients who underwent ophthalmologic examination had chorioretinal abnormalities. Three patients who underwent microbial cell-free deoxyribonucleic acid sequencing tested positive for M. chimaera, which was subsequently confirmed with blood culture growth. Echocardiography and positron emission tomography/computed tomography (PET/CT) revealed evidence of prosthetic valve/graft infection in 7/12 (58.3%) and 6/10 (60.0%) of cases, respectively. Seven patients (58.3%) underwent redo cardiovascular surgery. Of these, 1 patient died 2 days postdischarge, 1 experienced spinal osteomyelitis relapse, and another had interval prosthetic valve fluorodeoxyglucose (FDG) uptake on PET/CT suspicious for recurrent infection. Among 4 patients on medical therapy only, 3 expired or transitioned to hospice during follow-up.ConclusionsMCI continues to occur despite the FDA communications. Incorporation of ophthalmologic examination and use of advanced tools may improve MCI diagnosis. The mortality in these patients is high even with aggressive surgical/medical management.

Mycobacterium chimaera genomics with regard to epidemiological and clinical investigations conducted for the open-chest post-surgical Mycobacterium chimaera infections outbreak

Post-surgical infections due to Mycobacterium chimaera appeared as a novel nosocomial threat in 2015, with a worldwide outbreak due to contaminated heater-cooler units used in open chest surgery. We report the results of investigations conducted in France including whole genome sequencing comparison of patient and HCU isolates. Methods We sought M. chimaera infection cases from 2010 onwards through national epidemiological investigations in healthcare facilities performing cardiopulmonary bypass together with a survey on good practices and systematic heater-cooler unit microbial analyses. Clinical and HCU isolates were subjected to whole genome sequencing analyzed with regards to the reference outbreak strain Zuerich-1. Results Only two clinical cases were shown to be related to the outbreak, although 23% (41/175) heater-cooler units were declared positive for M. avium complex. Specific measures to prevent infection were applied in 89% (50/56) healthcare facilities although only 14% (8/56) of them followed the manufacturer maintenance recommendations. Whole genome sequencing comparison showed that the clinical isolates and 72% (26/36) of heater-cooler unit isolates belonged to the epidemic cluster. Within clinical isolates, 5 to 9 non-synonymous single nucleotide polymorphisms were observed, among which an in vivo mutation in a putative efflux pump gene observed in a clinical isolate obtained for one patient under antimicrobial treatment. Conclusions Cases of post-surgical M. chimaera infections were declared to be rare in France, although heater-cooler units were contaminated as in other countries. Genomic analyses confirmed the connection to the outbreak and identified specific single nucleotide polymorphisms, including one suggesting fitness evolution in vivo.

Ocular manifestations of disseminated Mycobacterium chimaera infection after cardiothoracic surgery

ObjectiveTo describe the ocular manifestations of disseminated Mycobacterium chimaera infection after cardiothoracic surgery. DesignRetrospective, observational case series. ParticipantsPatients with disseminated M. chimaera infection treated at the University of Alberta Hospital and Royal Alexandra Hospital in Edmonton, Alberta, Canada. MethodsSeven patients (14 eyes) with systemic M. chimaera infection after aortic graft and/or valvular surgeries were reviewed for ocular involvement. Cases were identified based on histopathologic analysis of cardiac tissue, repeat positive mycobacterial blood cultures, and cerebrospinal fluid analysis. Clinical ocular findings, fundus autofluorescence, fluorescein angiography, spectral-domain optical coherence tomography (SD-OCT), and autopsy results are described. ResultsThe mean age of our patients was 63 years (range, 22–76 years). Aortic graft and/or valvular surgeries were performed between June 2015 and April 2016. The mean duration from surgery to diagnosis of infection was 27 months (range, 19–36 months). All patients exhibited white-yellowish choroidal lesions. Bilateral, multifocal choroiditis was observed in 6 patients (12 eyes), who died of disseminated M. chimaera infection despite aggressive, multiagent antimicrobial therapy. One patient had a solitary, white-yellow choroidal lesion in the left eye only. Choroidal lesions were hyperfluorescent on late-phase fluorescein angiography and corresponded to localized choroidal thickening and retinal elevation on SD-OCT. ConclusionsM. chimaera infection after cardiothoracic surgery can cause life-threatening disease involving multiple organ systems. Ocular involvement is an important and possibly early clinical finding, with good correlation to systemic disease severity. Ophthalmological assessment and multimodal imaging may aid in early diagnosis and can be used to monitor disease progression.

Abstract 14789: Multimodality Imaging in Mycobacterium Chimaera Cardiovascular Infections

Introduction: Mycobacterium Chimaera (MC) infections following cardiovascular surgery are challenging to diagnose given their insidious presentation. We therefore reviewed the various imaging modalities used to diagnose these infections at Mayo Clinic. Methods: Cases from 01/01/2010-06/01/2020 were identified using electronic medical records. Demographics and clinical history were collected. Imaging studies, including transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), positron emission tomography / computed tomography (PET/CT), cardiac CT (CCT), and cardiac magnetic resonance (CMR) were reviewed. Results: A total of 7 patients (85.7% male) were found. 6 underwent aortic valve replacement and 1 received an aortic composite valve conduit. Surgical dates ranged from 01/2010-12/2018. Mean age at presentation was 63.3 years. Mean time from surgery to symptom onset was 28.0 months. All patients underwent TTE and TEE; prosthetic valve endocarditis was identified in 6 cases between both, while CMR established the diagnosis in 1 case. TTE showed prosthetic valve obstruction in 2 cases and an anterior pseudoaneurysm in 1 case. TEE findings included thickened prosthesis and/or vegetations (n=5), thickened posterior root (n=4), and root abscess (n=3). Among the 3 patients who underwent PET/CT, 2 demonstrated increased fluorodeoxyglucose (FDG) uptake around the aortic prosthesis; in addition, 1 had elevated FDG uptake in the myocardium suggesting myocarditis. 1 patient did not have aortic prosthesis FDG uptake. In the 2 patients who had CCT, 1 showed a pseudoaneurysm that prompted suspicion for endocarditis, and the other revealed a fluid collection adjacent to the aortic valve conduit. 2 patients underwent CMR; 1 had aortic prosthesis thickening and patchy areas of myocardial delayed enhancement suspicious for myocarditis, whereas the other showed vegetation and an aortic root abscess. Conclusion: TTE plus TEE successfully identified MC prosthetic valve endocarditis in most cases with TEE having higher specificity. Advanced imaging techniques are helpful to support the diagnosis and assess for myocardial and/or aortic involvement. Combining these modalities is therefore crucial in unveiling this elusive organism.