Pathologic Studies of Cases with Fungal Soft Tissue Infections after a Tornado – Joplin, Missouri, 2011
Wun-Ju Shieh, Clifton Drew, Shawn Lockhart, Christopher A Taylor, Lindy Liu, Dianna Blau, Chris Paddock, Lalitha Gade, Robyn Neblett Fanfair, George Turabelidze, Benjamin J Park, Mary E Brandt, Sherif R Zaki. Centers for Disease Control and Prevention (CDC), Atlanta, GA; Missouri Department of Health and Senior Services, Jefferson City, MO
Background: On May 22, 2011, an EF-5 tornado struck Joplin, Missouri, resulting in approximately 1,000 injuries and 159 deaths. A local physician initially identified two hospitalized patients with tornado injuries and necrotizing fungal infections in soft tissues. The Missouri Department of Health and Senior Services initiated active surveillance for such infections with epidemiologic and laboratory assistance from the Centers for Disease Control and Prevention (CDC).
Design: Tissue specimens from surgical debridement of 10 suspect cases were submitted to Infectious Diseases Pathology Branch (IDPB) at CDC for pathologic evaluation and testing. Histopathologic examination, special stains, and immunohistochemical (IHC) assays were performed at IDPB. DNA was extracted from paraffin tissue blocks and submitted to Mycotic Diseases Branch at CDC for molecular testing.
Results: Microscopic examination showed necrotizing inflammation in the soft tissues of all 10 cases. GMS and PAS stains demonstrated scattered fungal hyphae with bizarre shape, haphazard branching, and pauciseptation in 9 cases. Involvement of vascular wall with necrosis was observed in 4 cases. The above 9 cases were all positive for mucormycete fungi by IHC assay and 6 of them were further confirmed as the mucormycete Apophysomyces trapeziformis by PCR assay and by culture of the tissue. There were 3 IHC-positive cases with no fungal DNA amplified from the paraffin-embedded tissues. The single case negative for mucormycetes by IHC showed a mixture of small yeasts and septated fungal hyphae with right-angled branching. This case was positive for both Candida species and Aspergillus species by IHC, and PCR was positive for Fusarium species.
Conclusions: Many fungi can be present in traumatic wounds associated with natural disasters. Histologic evaluation, special stains, and IHC can demonstrate these fungi in the surgical debridement samples with corresponding tissue reactions. Therefore, pathologic studies in conjunction with molecular testing are essential to confirm the pathogenic role of these fungi in the wound infections. In this study, the mucormycete Apophysomyces trapeziformis was identified as the most frequent fungal pathogen in patients with tornado-associated soft tissue infections in Joplin, Missouri, 2011.
Monday, March 19, 2012 9:15 AM
Platform Session: Section H, Monday Morning