Methods: Following detection of a cluster of IMIs in patients with hematologic malignancies (HM) treated from Jul-Aug 2014, we reviewed center-based medical records of all patients with IMIs over a period from Jan 2012-Aug 2014; all were categorized into proven, probable and possible cases according to international criteria.
Results: A cluster of 6 patients with HM were identified with Rhizopus microsporus or azygosporus during a 6 week period from Jul-Aug 2014 (3 proven, 3 possible). Patients were diagnosed by a combination of culture, histopathology and molecular methods. All were positive by a laboratory developed PCR; 4 by culture and/or histopathology. During this period no other patients in the affiliated university hospital linked to this center were diagnosed with IMIs. Extensive environmental air sampling in both inpatient and outpatient departments did not reveal a source, but high local temperatures and nearby construction were thought to be potential links. Data from the prior 30 months identified 12 additional hematology patients with IMIs (8 proven, 4 possible), with a variety of Mucorales (Mucor spp., Rhizopus spp., Rhizomucor pusillus and Lichtheimia corymbifera).Microbiological diagnoses were made from a combination of culture (n=6), histopathology (8) and PCR (8); 4 by PCR alone. The median age was 61 (IQR 47, 68) years for all (n=18) cases, and most patients had acute leukemia (n=12) or had undergone hematopoietic cell transplantation (6). Nearly all cases had sinopulmonary infections (16; 89%); 4 had disseminated disease. All but one had a fatal outcome (94%).
Conclusion: We report a cluster of sinopulmonary IMIs in HM patients at our large comprehensive cancer center. Such outbreaks may remain unrecognized since clusters can be small, sporadic cases occur throughout the year, and there are no good diagnostic assays for these organisms. Molecular testing strategies improved case ascertainment, early recognition and management of these infections. However, as with other such clusters, extensive investigations did not reveal the source of airborne exposure.
D. Hoogestraat, None
R. Jain, None
P. Hendrie, None
E. Whimbey, None
S. Podczervinski, None
S. Pergam, Merck: Consultant , Consulting fee
Cubist: Consultant , Consulting fee
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