Mucormycosis: A Rare Complication of an Amputation

Post operative abdominal wall mucormycosis infection after laparotomy for bowel perforation

Mucormycosis is a devastating disease with a high mortality rate, typically affecting immunosuppressed individuals. Postoperative surgical site infections due to mucromycosis are rare, with only a handful of cases reported in the literature. Here, we describe a fatal case of post operative abdominal wound infection caused by mucormycosis in an immunocompetent man in his 70 s, who developed the infection following a laparotomy for bowel perforation. Initially, the growth of fungal species from a superficial wound swab was not considered significant until the patient exhibited signs of worsening sepsis. Limited operative debridement was performed for prognostication, in accordance with the family's wishes. There was evidence of extensive significant invasive fungal infection, marked by necrosis extending into the abdominal wall fat and muscle. The patient was then transitioned to comfort measures and subsequently died. This case emphasizes the importance of maintaining a high level of clinical suspicion for mucormycosis, even in patients with minimal risk factors, and highlights the importance of prompt and aggressive treatment.

Case report: The clinical utility of metagenomic next-generation sequencing in mucormycosis diagnosis caused by fatal Lichtheimia ramosa infection in pediatric neuroblastoma

Lichtheimia ramosa (L. ramosa) is an opportunistic fungal pathogen of the order Mucorales that may result in a rare but serious mucormycosis infection. Mucormycosis could be angioinvasive, causing thrombosis and necrosis in the nose, brain, digestive tract, and respiratory tract. The infection is highly lethal, especially in immunocompromised hosts, and the incidence has been on the rise. However, due to its relatively low incidence in pediatric population and the challenges with diagnosis, the awareness and management experience for pediatric mucormycosis are extremely limited, which might lead to poor outcomes. In this study, we comprehensively reviewed the course of a fatal rhinocerebral mucormycosis case in a pediatric neuroblastoma patient receiving chemotherapy. Due to a lack of awareness of the infection, the standard care of amphotericin B treatment was delayed and not administered until the identification of L. ramosa by metagenomic next-generation sequencing (mNGS)-based pan-pathogen detection of the patient's peripheral blood sample. We also reviewed the literature on L. ramosa infection cases reported worldwide between 2010 and 2022, with an analysis of clinical manifestation, prognosis, and epidemiological data. Our study not only highlighted the clinical value of comprehensive mNGS in rapid pathogen detection but also raised awareness of recognizing lethal fungal infection early in immunocompromised hosts including pediatric cancer patients.

Identification of Fungal Species and Detection of Azole-Resistance Mutations in the Aspergillus fumigatus cyp51A Gene at a South Korean Hospital

PURPOSE

With changing fungal epidemiology and azole resistance in Aspergillus species, identifying fungal species and susceptibility patterns is crucial to the management of aspergillosis and mucormycosis. The objectives of this study were to evaluate performance of panfungal polymerase chain reaction (PCR) assays on formalin-fixed paraffin embedded (FFPE) samples in the identification of fungal species and in the detection of azole-resistance mutations in the Aspergillus fumigatus cyp51A gene at a South Korean hospital.

MATERIALS AND METHODS

A total of 75 FFPE specimens with a histopathological diagnosis of aspergillosis or mucormycosis were identified during the 10-year study period (2006-2015). After deparaffinization and DNA extraction, panfungal PCR assays were conducted on FFPE samples for fungal species identification. The identified fungal species were compared with histopathological diagnosis. On samples identified as A. fumigatus, sequencing to identify frequent mutations in the cyp51A gene [tandem repeat 46 (TR46), L98H, and M220 alterations] that confer azole resistance was performed.

RESULTS

Specific fungal DNA was identified in 31 (41.3%) FFPE samples, and of these, 16 samples of specific fungal DNA were in accord with a histopathological diagnosis of aspergillosis or mucormycosis; 15 samples had discordant histopathology and PCR results. No azole-mediating cyp51A gene mutation was noted among nine cases of aspergillosis. Moreover, no cyp51A mutations were identified among three cases with history of prior azole use.

CONCLUSION

Panfungal PCR assay with FFPE samples may provide additional information of use to fungal species identification. No azole-resistance mediating mutations in the A. fumigatus cyp51A gene were identified among FFPE samples during study period.

Occurrence of Trichophyton verrucosum in cattle in the Ningxia Hui autonomous region, China

Background

Ningxia Hui Autonomous Region is an important cattle breeding area in China, and cattle breeding bases are located in this area. In Ningxia, dermatophytes have not been paid attention to, so dermatophytosis is becoming more and more serious. For effective control measures, it is important to determine the disease prevalence and isolate and identify the pathogenic microorganism.

Results

The study showed the prevalence of dermatophytes was 15.35% (74/482). The prevalence in calf was higher than adult cattle (p < 0.05). The morbidity was the highest in winter compared with autumn (p < 0.0001), summer (p < 0.05) and spring (p < 0.0001). The prevalence in Guyuan was the highest compared with Yinchuan (p < 0.05) and Shizuishan (p < 0.05). The incidence of lesions on the face, head, neck, trunk and whole body was 20.43, 38.71, 20.43, 10.75 and 9.68%, respectively. From all samples, the isolation rate of Trichophyton was highest (61.1%). The phylogenetic tree constructed showed that the 11 pathogenic fungi were on the same branch as Trichophyton verrucosum.

Conclusions

This study reports, for the first time, the presence of Trichophyton verrucosum in cattle in Ningxia and showed that the incidence of dermatophytosis is related to different regions, ages and seasons. A better knowledge of the prevalence of dermatophytosis of cattle may allow the adoption of more efficient control measures and prophylaxis.

First Case of Rhinocerebral Mucormycosis Caused by Lichtheimia ornata, with a Review of Lichtheimia Infections

BACKGROUND

Lichtheimia species are emerging opportunistic fungal pathogens in the Mucorales, causing serious skin and respiratory infections in immunocompromised patients. Established agents are Lichtheimia corymbifera and L. ramosa, while L. ornata is a novel agent. Available data on a species-specific analysis of Lichtheimia infections are limited.

METHODS

The first case of a fatal rhino-orbital-cerebral infection in a hematopoietic stem cell transplantation recipient caused by L. ornata is reported; the agent was identified by sequencing the ITS ribosomal region. We reviewed the literature on mucormycosis due to Lichtheimia species between 2009 and 2018, with an analysis of risk factors and epidemiological and clinical data.

RESULTS

In addition to our Lichtheimia ornata case, 44 cases of human Lichtheimia were analyzed. Lichtheimia predominated in Europe (68.2%), followed by Asia (16%), and Africa (9%). The most common underlying condition was hematological malignancy (36.3%), followed by trauma/major surgery (27.3%), while diabetes mellitus was rare (11.4%). Site of infection was mostly skin and soft tissues (45.5%) and lung (25%), while relatively few cases were disseminated (13.6%) or rhinocerebral (11.4%). Mortality (36.4%) was mainly due to disseminated and rhinocerebral infections.

CONCLUSION

In contrast to Rhizopus, the most common agent of mucormycosis recorded in patients with diabetes mellitus, Lichtheimia infections were primarily associated with hematological malignancies and major skin barrier damage. Given the fact that classical rhinocerebral mucormycosis remains difficult to treat, independent of causative species, timely application of amphotericin B accessory to debridement may be required for patient survival.