We recently mitigated a clonal outbreak of Mycobacterium abscessus, including a large cluster of patients who developed invasive infection after exposure to heater-cooler units (HCU) during cardiac surgery. Recent studies have described a small number of Mycobacterium chimaera infections linked to open heart surgery; however, little is known about the epidemiology and clinical courses of cardiac surgery patients with invasive infection from rapidly-growing mycobacteria, such as M. abscessus.
We retrospectively collected clinical data from all patients who underwent cardiac surgery at our hospital and had positive cultures for M. abscessus from 2013-2016. We excluded heart transplant recipients and patients who at time of diagnosis had ventricular assist devices. We analyzed patient characteristics, antibiotic treatment courses, surgical interventions, and clinical outcomes.
Nine cardiac surgery patients who met the case definition developed culture-proven invasive infection from M. abscessus (Figure 1). Seven (78%) infections occurred after surgeries that included valve replacement. Median time from suspected inoculation in the operating room to first positive culture was 49 days (interquartile range, 38-115 days). Seven (78%) patients had bloodstream infections, and six (67%) patients had sternal wound infections. Six (67%) patients developed disseminated disease with infection at multiple sites.
All patients received combination antimicrobial therapy. The most common majority regimen (n=6) was imipenem, amikacin, and tigecycline. Four (44%) patients experienced therapy-limiting antibiotic toxicities (Figure 2). Seven (78%) patients were well enough to undergo at least one surgical debridement. Five (56%) patients stopped therapy due to presumed cure, but four (44%) patients had deaths attributable to M. abscessus infection.
Invasive M. abscessus infection after cardiac surgery was associated with high morbidity and mortality. Most patients underwent surgical debridement and received prolonged three-drug antimicrobial therapy, which was complicated by numerous antibiotic toxicities. Treatment cured five patients, but four patients died from mycobacterial disease.
A. W. Baker,
S. S. Lewis, None
J. E. Stout, None
D. J. Anderson, None
P. K. Smith, None
J. N. Schroder, None
M. A. Daneshmand, None
B. D. Alexander, None
D. J. Sexton, None
C. R. Wolfe, None
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