DOI: 10.5061/dryad.qnk98sfdd
title: Nocardia Infections

description: Nocardial infections have been rare after allogeneic hematopoietic stem
 cell transplantation (HSCT). We report 10 recent cases of late-onset
 nocardiosis (median time of onset of 508 days after transplantation)
 primarily in patients on high doses of corticosteroids for
 graft-versus-host disease. All 10 patients had pulmonary infection caused
 by Nocardia species susceptible to trimethoprim-sulfamethoxazole
 (TMP-SMX). At time of diagnosis 8 of 10 patients were not receiving
 TMP-SMX for prophylaxis of Pneumocystis jiroveci pneumonia (PJP; 7 on
 atovaquone, 1 on i.v. pentamidine). After the initiation of atovaquone
 prophylaxis for PJP in place of TMP-SMX for many UCLA allogeneic HSCT
 patients in 2012, 9 cases of nocardiosis occurred in 411 patients (2.2%)
 over the next 6 years (2012 to 2017) compared with only 1 case in 575
 patients (0.17%) during the previous 12 years (2000 to 2011). Although
 there were no deaths directly related to nocardial infection treated
 primarily with TMP-SMX, overall mortality in this group of patients was
 40%. Based on this experience, the use of atovaquone for PJP prophylaxis
 in place of TMP-SMX may be associated with an increased risk for
 previously rare nocardial infections after allogeneic HSCT.
description: A retrospective review of patients' medical records and UCLA
 Clinical Microbiology Laboratory culture results was performed to identify
 allogeneic HSCT recipients with a diagnosis of nocardiosis between January
 1, 2000 and August 30, 2017. Baseline patient characteristics, underlying
 disease, allograft type, conditioning regimen, pretransplant and donor
 cytomegalovirus serology, immunosuppressive agents, and graft-versus-host
 disease (GVHD) status were collected. The clinical features
 of <em>Nocardia</em> infection and PJP prophylaxis at the time
 of diagnosis were also included in this review. The diagnosis of
 nocardiosis was made based on at least 1 culture of respiratory secretions
 or blood positive for <em>Nocardia</em> from a patient with
 clinical features of <em>Nocardia</em> infection not
 explainable by other causes.
 All <em>Nocardia</em> isolates were identified in the
 UCLA Clinical Microbiology Laboratory. Before 2013 a 7H11 solid media was
 used to recover <em>Nocardia</em> from clinical specimens.
 From 2013 to the present a buffered-charcoal yeast extract media was used
 to enhance recovery of <em>Nocardia</em> from cultures. All
 cultures were held for at least 3 weeks and examined daily for growth.
 Before 2013 <em>Nocardia</em> susceptibility testing was
 performed by an outside reference laboratory (Quest Diagnostics Infectious
 Disease, Inc., San Juan Capistrano, CA). After
 2013 <em>Nocardia</em> susceptibility testing was performed at
 the UCLA Clinical Microbiology
 Laboratory. <em>Nocardia</em> susceptibility testing was
 performed at both Quest Diagnostics Infectious Disease and at UCLA, using
 broth microdilution trays. After inoculation of organisms, these trays are
 incubated for 72 hours and then read per standard antimicrobial
 susceptibility testing protocols to determine minimum inhibitory
 concentrations. CLSI M24-A2 susceptibility breakpoints are used.