Frequency of occurrence, seasonal variation and antifungal susceptibility of opportunistic Mucorales isolated from hospital soils in Iran

Features and evaluation of mucormycosis in COVID-19 patients from two referral hospitals in Iran

OBJECTIVES

The present study aimed to assess the features, clinical characteristics, and species diversity among patients admitted to referral Hospitals for SARS-CoV-2 pneumonia and mucormycosis in Tehran, Iran, and the relationship between seasonal and species diversity was considered.

METHODS

Confirmed COVID-19 patients with a positive reverse-transcriptase real-time (rRT-PCR) test for SARS-CoV2 were primarily included based on clinically suspected mucormycosis infection and confirmed by histopathology and mycology examination of biopsy specimens. The PCR technique was performed by the amplification of the high-affinity iron permease 1 (FTR1) gene for identification and discrimination between Rhizopus arrhizus and non- Rhizopus arrhizus isolates. In contrast, species identification of non-Rhizopus arrhizus was performed by sequencing of ITS rDNA region.

RESULTS

Rhino-sino-orbital mucormycosis was identified in the majority of cases (n = 33), with 66 % and 34 % of the cases involving male and female patients, respectively. Rhizopus arrhizus was found to be the most prevalent (84.6 %), followed by Mucor circinelloides (7.6 %). Rhizopus arrhizus was the most prevalent species and present in all the seasons; however, Mucor circinelloides was only present in the autumn. The overall mortality of the total population was 24.6 % (16/ 65); the mortality rates occurring in patients diagnosed with rhino-sino-orbital infection and rhino-sinusal form were 21.4 % and 25 %, respectively.

CONCLUSION

CAM can be a serious complication of severe COVID-19, especially in patients with uncontrolled diabetes. It is important to monitor the epidemiology of mucormycosis to raise awareness of the disease and improve diagnosis, treatment and prognosis, particularly in the setting of pandemic.

Mucormycosis: A 14-Year Retrospective Study from a Tertiary Care Center in Lebanon

Mucormycosis (MCM) is a serious invasive fungal disease (IFD) that is associated with high mortality, particularly in immunocompromised patients. A global surge in MCM cases was reported with the COVID-19 pandemic. We analyzed all recorded cases of MCM at the American University of Beirut Medical Center (AUBMC), a tertiary care center in Lebanon, over 14 years. We aimed to identify the incidence, seasonal variation, clinical characteristics of the patients, and predictors of mortality. We conducted a retrospective chart review between 1 January 2008 and 1 January 2023. All patients with proven or probable MCM were included in the study. Proven or probable MCM was defined by positive histopathology and/or positive cultures. A total of 43 patients were identified as having MCM. Their median age was 53 years, and the majority were males (58.1%). Most of the cases were diagnosed in the autumn season. In total, 67.4% of the patients had hematological malignancies (HMs), and 34.9% had uncontrolled diabetes mellitus (DM). The most common site of involvement was rhino-orbital-cerebral MCM (ROCM) (74%). The annual cases of MCM per 100,000 patient days increased markedly during the years of the COVID-19 pandemic (from 0 to 4.4 cases/100,000 patient days to 7.5 cases/100,000 during 2020 and 2021). Liposomal amphotericin (Ampho) B was used as a first-line agent in most of the patients (86%). The median duration of total in-hospital antifungal therapy was 21 days and 51.2% of the patients received step-down therapy with azoles. Surgical debridement and isolated ROCM were significantly associated with survival (p-value: 0.02 and <0.001, respectively). All-cause mortality was 46.7%, with chronic renal disease being significantly associated with mortality (p-value < 0.05). The incidence of MCM has been increasing at our institution, particularly since the COVID-19 pandemic. Early diagnosis, treatment, and surgical debridement improve patient outcomes and overall survival.

Could cattle dung burning have contributed to the epidemic of COVID-19-associated mucormycosis in India? Results of an experimental aero-mycological study

Background

Several hypotheses have been proposed for explaining the outbreak of coronavirus disease 2019 (COVID‐19)‐associated mucormycosis in India, including the burning of cattle dung cakes, though no study has yet been conducted to support this claim.

Methods

We conducted an aero‐mycological study to evaluate whether Mucorales in the air increased during or after burning cattle dung cakes. We further compared the growth of Mucorales in the indoor air samples from houses with and without cattle. We also cultured fresh and dried cattle dung and soil samples for Mucorales.

Results

We noted no significant difference in the proportion of air samples growing Mucorales during (4/22 [18.2%]) and after (3/2 [13.6%]) cattle dung burning than that collected immediately before (4/22 [18.2%]). Mucorales were isolated in 15.4% of the indoor air samples obtained from different houses (both rural and urban); the proportion of samples growing Mucorales was not significantly different in households with and without cattle. We also observed growth of Mucorales in 6 of the 8 [75%] fresh and 3 of the 6 [50%] dried dung samples. The most common Mucorales isolated from soil and dung samples was Lichtheimia corymbifera, while Rhizopus arrhizus was the most common species isolated from indoor air samples.

Conclusions

We found no significant increase in the proportion of air samples growing Mucorales during or after burning cattle dung cake than that before. It seems unlikely that cattle dung burning contributes to the occurrence of mucormycosis.

New insights on mucormycosis and its association with the COVID-19 pandemic

COVID-19 continues to cause significant fatality worldwide. Glucocorticoids prove to play essential roles in COVID-19 management; however, the extensive use of steroids together with the virus immune dysregulation may increase the danger of secondary infections with mucormycosis, an angioinvasive fungal infection. Unfortunately, a definite correlation between COVID-19 and elevated mucormycosis infection cases is now clear worldwide. In this review, we discuss the historical record and epidemiology of mucormycosis as well as pathogenesis and associated host immune response, risk factors, clinical presentation, diagnosis and treatment. Special emphasis is given to its association with the current COVID-19 pandemic, including latest updates on COVID-19-associated mucormycosis cases globally, with recommendations for efficacious management.

Utility of itraconazole and terbinafine in mucormycosis: a proof-of-concept analysis

An epidemic of mucormycosis followed the second wave of COVID 19 in the state of Uttar Pradesh, India in May 2021. This epidemic, however, had additional challenges to offer in the form of acute shortage of all forms of amphotericin B, posaconazole and isavuconazole. It was, therefore, planned to assess the trends in minimum inhibitory concentration (MIC) of antifungal agents, viz itraconazole and terbinafine, and provide a template for personalized therapy to see whether the results could be translated clinically. This is an observational, single-center study. Samples comprising nasal swab, nasal and paranasal sinus tissue, brain tissue, brain abscess and orbital content, derived from 322 patients from northern India with mucormycosis, of whom 215 were male and 107 were female, were used for analysis. Cultures were identified both by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and conventional methods of identification. Antifungal susceptibility was done for amphotericin B, posaconazole, isavuconazole, itraconazole and terbinafine as per Clinical Laboratory Standard Institute M38-A2. The outcome was identification of the species of mucormycosis and susceptibility to itraconazole and terbinafine besides other primary antifungal agents. Patients or the public were not involved in the design, or conduct, or reporting or in the dissemination plans of our research. Of 322 patients, 203 were culture-positive, of whom 173 were positive by both MALDI-TOF and conventional methods of identification. Final antifungal susceptibility testing was available for 150 patients. The most common Mucorales found to cause this epidemic was Rhizopus oryzae, followed by R. microsporus Amphotericin B, posaconazole and isavuconazole had low MIC values in 98.8% of all Mucorales identified. The MIC of itraconazole was species-dependent. 97.7% of R oryzae had MIC ≤2 µg/mL. However, only 36.5% of R microsporus had MIC ≤2 µg/mL. For terbinafine, 85.2% of R. microsporus had MIC ≤2 µg/mL. We conclude that identification at the species level is required as antifungal susceptibilities seem to be species-dependent. Assessment of the efficacy of itraconazole and terbinafine warrants further studies with clinical assessment and therapeutic drug monitoring as they seem to be potential candidates especially when the primary agents are not available.

COVID-19-Associated Mucormycosis, A New Incident in Recent Time: Is An Emerging Disease in The Near Future Impending?

Mucormycosis (also known as black fungus) is caused by fungi of the Zygomycetes class and is the third most common invasive mycosis after candidiasis and aspergillosis. They colonize a large number of patients without invading them. Systemic glucocorticoids are currently used to treat severe Coronavirus disease 19 (COVID-19). In such patients, opportunistic fungal infections are a problem. Although COVID-19-related pulmonary aspergillosis is becoming more common, mucormycosis is still uncommon. Mucormycosis normally appears 10 to 14 days after being admitted to the hospital. Mucormycosis is a rare but dangerous infection that can make extreme COVID-19 worse. Mucormycosis is more likely to occur in people who have diabetes mellitus and other risk factors. Mucormycosis is most likely exacerbated by concurrent glucocorticoid treatment. To improve outcomes, a high index of suspicion and aggressive management is required. Excessive usage of steroids, monoclonal antibodies, and broad-spectrum antibiotics might cause the formation or worsen of a fungal infection. A high index of suspicion and aggressive management are needed. In patients with COVID-19 infection, physicians should be vigilant of the likelihood of subsequent invasive fungal infections. To enhance results in pulmonary mucormycosis, early diagnosis and treatment are critical. Confirmation of the clinical form necessitates a combination of symptoms that are consistent with tissue invasion histologically. Combining various clinical data and the isolation of the fungus from clinical samples in culture is needed for the probable diagnosis of mucormycosis. The organism that causes mucormycosis is identified using macroscopic and microscopic morphological criteria, carbohydrate assimilation, and the maximum temperature at which they can expand. Mucormycosis must be treated with antifungal medication prescribed by a doctor. It may necessitate surgery in some circumstances, and it can result in the loss of the upper jaw and, in some situations, an eye.

Risk Factors for Mucormycosis in COVID-19 Patients

: Opportunistic infections, such as mucormycosis, in coronavirus disease 2019 (COVID-19) patients has become a new health challenge. Since opportunistic infections can exacerbate COVID-19 patients' status, it is vital to identify the risk factors to prevent, diagnose, and treat them as soon as possible. Viral, fungal, environmental, and host factors may be responsible for this situation. Long hospital stays, impaired host immune system function due to viral infection, and excessive consumption of glucocorticoids in managing COVID-19 patients are the main risk factors for the increased risk of mucormycosis in COVID-19 patients. Educating health care workers and considering the association between mucormycosis of the paranasal sinuses and different strains of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the cause of COVID-19 can help prevent invasive fungal sinusitis in COVID-19 patients.

Epidemiology and Antifungal Susceptibilities of Mucoralean Fungi in Clinical Samples from the United States

The global incidence of mucormycosis has increased in recent years owing to higher numbers of individuals at risk for these infections. The diagnosis and treatment of this aggressive fungal infection are of clinical concern due to differences in species distribution in different geographic areas and susceptibility profiles between different species that are capable of causing highly aggressive infections. The purpose of this study was to evaluate the epidemiology and susceptibility profiles of Mucorales isolates in the United States over a 52-month period. Species identification was performed by combined phenotypic characteristics and DNA sequence analysis, and antifungal susceptibility testing was performed by CLSI M38 broth microdilution for amphotericin B, isavuconazole, itraconazole, and posaconazole. During this time frame, 854 isolates were included, representing 11 different genera and over 26 species, of which Rhizopus (58.6%) was the predominant genus, followed by Mucor (19.6%). The majority of isolates were cultured from the upper and lower respiratory tracts (55%). Amphotericin B demonstrated the most potent in vitro activity, with geometric mean (GM) MICs of ≤0.25 μg/ml against all genera with the exception of Cunninghamella species (GM MIC of 1.30 μg/ml). In head-to-head comparisons, the most active azole was posaconazole, followed by isavuconazole. Differences in azole and amphotericin B susceptibility patterns were observed between the genera with the greatest variability observed with isavuconazole. Awareness of the epidemiology of Mucorales isolates and differences in antifungal susceptibility patterns in the United States may aide clinicians in choosing antifungal treatment regimens. Further studies are warranted to correlate these findings with clinical outcomes.