Zygomycosis caused by Rhizopus microsporus and Rhizopus oryzae in Madhya Pradesh (M.P.) Central India: a report of two cases

A meta-analysis of survival factors in rhino-orbital-cerebral mucormycosis-has anything changed in the past 20 years?

BACKGROUND

Rhino-orbital-cerebral mucormycosis (ROCM) is an uncommon yet potentially lethal fungal infection. Although most cases originate from developing countries, an ageing population and increased prevalence of chronic illness may mean some clinicians practicing in developed countries will encounter ROCM cases in their careers. Yohai et al published a systematic review of 145 case reports from 1970 to 1993 assessing prognostic factors for patients presenting with ROCM. We present an updated review of the literature and assess whether survival outcomes have changed in the two decades since that seminal paper.

SEARCH STRATEGY

An extensive Medline literature search was performed for case reports published between 1994 and 2015.

RESULTS

In total, 210 published cases were identified from the literature review, of which 175 patients from 140 papers were included in this review. Fifty-five were female, with an overall mean age of 43 years. Overall survival rate was 59.5%, which was not significantly better than the previous series reported (60%) reported by Yohai et al. Survival rates in patients with chronic renal disease had improved, from 19% to 52%, and in patients with leukaemia (from 13% to 50%). Facial necrosis and hemiplegia remained poor prognostic indicators (33% and 39% survival rates, respectively). Early commencement of medical treatment related to better survival outcomes (61% if commenced within first 12 days of presentation, compared to 33% if after 13 days). Timing of surgery had less of an effect on overall survival. However, in 28 cases that did not receive any surgical treatment, survival was only 21%.

CONCLUSIONS

Although overall survival rates have not improved, survival in patients with renal disease were better, potentially due to the introduction of liposomal amphotericin B which is less nephrotoxic. Prompt recognition of ROCM, reversal of predisposing co-morbidities and aggressive medical treatment remain the cornerstone of managing this highly aggressive disease.

Diversity of mucoralean fungi in soils of papaya (Carica papaya L.) producing regions in Mexico

Mexico is the fifth largest producer of papaya worldwide and has recently reported problems with mucoralean fungi in this crop. These fungi are considered saprophytes in the soil and are ubiquitous in nature. In this work, they were isolated from soil in regions of intensive papaya cultivation in Mexico. Collections were made in the states of Colima, Oaxaca and Veracruz in Apr 2016. A total of 72 mucorales fungal isolates was obtained and morphologically characterized and then molecular characterization (28S ribosomal region) of 25 representative isolates was carried out. Phylogenetic analysis of the sequences confirmed the presence of the species Gilbertella persicaria, Rhizopus oryzae, Rhizopus stolonifer, Mucor circinelloides and Mucor hiemalis, which cause soft rot in papaya fruits, therefore, spores of these fungi found in the orchard soils can be considered as a constant source of contamination that affects healthy fruits. Additionally, Choanephora cucurbitarum, Mucor ellipsoideus, Rhizopus homothallicus, Rhizopus microsporus, Rhizopus schipperae, Lichteimia ramosa, Gongronella butleri, Cunninghamella bertholletiae and Cunninghamella blakesleeana were identified which are considered to have agricultural, biotechnological and medical importance.

Purification, Cloning and Immuno-Biochemical Characterization of a Fungal Aspartic Protease Allergen Rhi o 1 from the Airborne Mold Rhizopus oryzae

BACKGROUND

Fungal allergy is considered as serious health problem worldwide and is increasing at an alarming rate in the industrialized areas. Rhizopus oyzae is a ubiquitously present airborne pathogenic mold and an important source of inhalant allergens for the atopic population of India. Here, we report the biochemical and immunological features of its 44 kDa sero-reactive aspartic protease allergen, which is given the official designation 'Rhi o 1'.

METHOD

The natural Rhi o 1 was purified by sequential column chromatography and its amino acid sequence was determined by mass spectrometry and N-terminal sequencing. Based on its amino acid sequence, the cDNA sequence was identified, cloned and expressed to produce recombinant Rhi o 1. The allergenic activity of rRhi o 1 was assessed by means of its IgE reactivity and histamine release ability. The biochemical property of Rhi o 1 was studied by enzyme assay. IgE-inhibition experiments were performed to identify its cross-reactivity with the German cockroach aspartic protease allergen Bla g 2. For precise characterization of the cross-reactive epitope, we used anti-Bla g 2 monoclonal antibodies for their antigenic specificity towards Rhi o 1. A homology based model of Rhi o 1 was built and mapping of the cross-reactive conformational epitope was done using certain in silico structural studies.

RESULTS

The purified natural nRhi o 1 was identified as an endopeptidase. The full length allergen cDNA was expressed and purified as recombinant rRhi o 1. Purified rRhi o 1 displayed complete allergenicity similar to the native nRhi o 1. It was recognized by the serum IgE of the selected mold allergy patients and efficiently induced histamine release from the sensitized PBMC cells. This allergen was identified as an active aspartic protease functional in low pH. The Rhi o 1 showed cross reactivity with the cockroach allergen Bla g 2, as it can inhibit IgE binding to rBla g 2 up to certain level. The rBla g 2 was also found to cross-stimulate histamine release from the effector cells sensitized with anti-Rhi o 1 serum IgE. This cross-reactivity was found to be mediated by a common mAb4C3 recognizable conformational epitope. Bioinformatic studies revealed high degree of structural resemblances between the 4C3 binding sites of both the allergens.

CONCLUSION/SIGNIFICANCE

The present study reports for the first time anew fungal aspartic protease allergen designated as Rhi o 1, which triggers IgE-mediated sensitization leading to various allergic diseases. Here we have characterized the recombinant Rhi o 1 and its immunological features including cross-reactive epitope information that will facilitate the component-resolved diagnosis of mold allergy.

[Sinonasal mucormycosis revealed by a necrotic velar ulceration]

INTRODUCTION

Mucormycosis is a deep mycosis which has been spreading out in recent years. It is still poorly understood and poorly described in sub-Saharan Africa. The authors report a case of sinonasal localization, of fatal evolution and late diagnosis in a young child.

OBSERVATION

It is about a 13-year-old child suffering from chronic rhinosinus syndrome for two years. He was observed in stomatology for a necrotic velar ulceration that have occurred for three months. The clinical, radiological and histological explorations were in favor of a sinonasal mucormycosis. The administration of amphotericin B and the surgical treatment did not slow down the fatal evolution.

CONCLUSION

Mucormycosis should not be dealt with any diagnostic error and no therapeutic improvisation. It has to be thought about when dealing with a rhinosinusal syndrome with cleft ulceration.