Update on Actinomucor elegans, a mucormycete infrequently detected in human specimens: how combined microbiological tools contribute efficiently to a more accurate medical care

Actinomucor elegans is a fungus belonging to mucormycetes and is still probably underdiagnosed due to misidentification. Based on a recent first case of Actinomucor elegans sinusitis in Europe, in an immunocompromised patient under voriconazole treatment, this paper aims to summarize knowledge about A. elegans mucormycoses. Even if the diagnosis of mucormycosis was made using traditional mycology techniques, precise identification of the fungus could only be achieved using molecular tools. In this observation, the galactomannan dosage was positive until the introduction of treatment and surgical debridement. The patient experienced no relapse after one year. By reviewing the four previous A. elegans reported cases and describing the mycological characteristics of this species, we highlight the need to use a combination of tools to improve the diagnostic strategy in such rare and life-threatening clinical situations.

Species of Metarhizium anisopliae complex implicated in human infections: retrospective sequencing study

OBJECTIVES

Fungi belonging to the Metarhizium anisopliae complex comprise ubiquitous arthropod pathogenic moulds used as mycopesticides. Rare cases of human infections due to M. anisopliae have been reported. We hypothesize misidentifications of fungal strains implicated in these cases or used in mycopesticides.

METHODS

A review of the literature was conducted to identify previously published cases. We collected some of these previous described strains and reported new cases, and a French mycopesticide containing M. anisopliae. All identifications were performed based on elongation factor-1α gene sequencing.

RESULTS

We report eight new cases of Metarhizium infection in humans (three from France and five from Australia). The strains isolated from these cases, and three others from already published cases and reported as M. anisopliae, were molecularly identified based on elongation factor-1α (Ef1-α) gene sequencing as follows: Metarhizium robertsii (six), Metarhizium guizhouense (three), Metarhizium brunneum (one) and Metarhizium pingshaense (one).

CONCLUSIONS

In this study, we report new human cases of Metarhizium infections, and, based on Ef-1α gene sequencing, we demonstrate the misidentification of species in case reports. We also correct the species identification of a strain reported as M. anisopliae used in a commercially available mycopesticide. According to our results, none of the strains from the human infection reports reviewed belongs to the species M. anisopliae.

[From guinea pig to man: Tinea outbreak due to Trichophyton mentagrophytes var. porcellae in pet shops in Nancy (France)]

Dermatophytes are responsible for widespread superficial fungal infections, currently representing a real public health problem. Some of the fungi involved in these mycoses are transmitted by pets, illustrating great host specificity within this fungal group. Thus, a new variety of zoophilic dermatophyte has been described in recent years by the Mycology Laboratory of the University Hospital of Nancy, within the complex T. mentagrophytes. This variant was named T. mentagrophytes var. porcellae, following the observation of a significant number of patients with dermatomycoses of exposed parts of the body and having had contact with a guinea pig. The current work follows this first description and aims to assess the frequency of T. mentagrophytes var. porcellae in guinea pigs within three pet shops in the region of Nancy (France). In total, almost two thirds of collected guinea pigs were carriers of this new dermatophyte. This study highlights the risks associated with the adaptation of dermatophytes to potential new hosts that may spread to new species. Thus, in this context, sanitary measures could be proposed to the pet shops, usually not informed of the risks facing the growing enthusiasm of the population for new pets, in order to limit contamination.

X-ray microanalysis of airway surface liquid collected in cystic fibrosis mice

The airway surface liquid (ASL) that lines the airway surface epithelium plays a major role in airway antibacterial defense and mucociliary transport efficiency, two key factors in cystic fibrosis (CF) disease. A major difficulty is to collect ASL in native conditions without stimulation or alteration of the underlying airway epithelium. Using a cryoprobe specifically adapted to collect native ASL from the tracheal mouse surface, we analyzed by X-ray microanalysis the complete ASL and plasma ion content in Cftr(tm1Hgu)/Cftr(tm1Hgu) mice compared with that in control littermates. ASL ion content from eight Cftr(tm1Hgu)/Cftr(tm1Hgu) mice and eight control littermates did not appear significantly different. The mean (+/-SE) concentrations were 2,352 +/- 367 and 2,058 +/- 401 mmol/kg dry weight for Na, 1,659 +/- 272 and 1,448 +/- 281 mmol/kg dry weight for Cl, 357 +/- 57 and 337 +/- 38 mmol/kg dry weight for S, 1,066 +/- 220 and 787 +/- 182 mmol/kg dry weight for K, 400 +/- 82 and 301 +/- 58 mmol/kg dry weight for Ca, 105 +/- 31 and 105 +/- 20 mmol/kg dry weight for Mg, 33 +/- 15 and 29 +/- 9 mmol/kg dry weight for P in non-CF and CF mice, respectively. This cryotechnique appears to be a promising technique for analyzing the complete elemental composition of native ASL in CF and non-CF tissues.

The mouse bagpipe gene controls development of axial skeleton, skull, and spleen

The mouse Bapx1 gene is homologous to the Drosophila homeobox containing bagpipe (bap) gene. A shared characteristic of the genes in these two organisms is expression in gut mesoderm. In Drosophila, bap functions to specify the formation of the musculature of the midgut. To determine the function of the mammalian cognate, we targeted a mutation into the Bapx1 locus. Bapx1, similar to Drosophila, does have a conspicuous role in gut mesoderm; however, this appears to be restricted to development of the spleen. In addition, Bapx1 has a major role in the development of the axial skeleton. Loss of Bapx1 affects the distribution of sclerotomal cells, markedly reducing the number that appear ventromedially around the notochord. Subsequently, the structures in the midaxial region, the intervertebral discs, and centra of the vertebral bodies, fail to form. Abnormalities are also found in those bones of the basal skull (basioccipital and basisphenoid bones) associated with the notochord. We postulate that Bapx1 confers the capacity of cells to interact with the notochord, effecting inductive interactions essential for development of the vertebral column and chondrocranium.

The mouse Dazla gene encodes a cytoplasmic protein essential for gametogenesis

RBM and DAZ/SPGY are two families of genes located on the Y chromosome that encode proteins containing RNA-binding motifs, and both have been described as candidate human spermatogenesis genes. Transmission of deletions from father to son has been observed in the case of DAZ, but neither gene family has been shown to be essential for spermatogenesis in human males. The DAZ/SPGY genes are particularly amenable to a knockout approach, as they are found on the Y chromosome in Old World primates and apes, but in other mammals, they are represented only by an autosomal gene, DAZLA, which is also present in Old World primates and apes. It has also been shown that a Dazla homologue is essential for spermatogenesis in Drosophila. Here we show that Dazla protein is cytoplasmic in male and female germ cells, unlike the nuclear RBM protein. Disruption of the Dazla gene leads to loss of germ cells and complete absence of gamete production, demonstrating that Dazla is essential for the differentiation of germ cells.