Abstract
Purpose :
An increasing number of patients have developed severe Mycobacterium chimaera infection after cardiac surgery. Infections are publicly reported in 11 countries and are thought to be related to airborne transmission of aerosolized bacteria from intrinsic contamination of heater-cooler units. We performed a retrospective, observational case series of the 7 known cases of disseminated M. chimaera infection in Alberta.
Methods :
Seven patients (14 eyes), with systemic M. chimaera infection, were reviewed for ocular involvement. Cases were identified based on repeat positive mycobacterial blood cultures, cerebrospinal fluid analysis, and histopathologic analysis of cardiac tissue. Clinical ocular findings, fundus autofluorescence, fluorescein angiography, and spectral-domain optical coherence tomography (SD-OCT) findings are described.
Results :
The 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). Clinical ocular findings included white-yellowish choroidal lesions, white edematous choroidal thickening, and central retinal vein occlusion. Bilateral multifocal choroiditis was observed in 6 patients. One patient was asymptomatic with a solitary, white, granular choroidal lesion in the left eye only. Choroidal lesions were hyperfluorescent on fluorescein angiography and corresponded to localized choroidal thickening and retinal elevation on SD-OCT. In this series, the extent of choroidal lesions was indicative of systemic disease control. Three patients with widespread choroidal lesions died of disseminated M. chimaera infection despite aggressive, multi-agent, antimicrobial therapy. They demonstrated progressive choroiditis, increase in lesion size, and appearance of new lesions. Cerebral autopsy of two patients showed widespread, severe granulomatous encephalitis, involving several structures of the central nervous system, and mild diffuse inflammation of the leptomeninges.
Conclusions :
M. chimaera infection following cardiac 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.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.