An Unusual Source for Apophysomyces elegans and a Method for Stimulating Sporulation of Saksenaea vasiformis

Ellis, J. J.; Ajello, Libero

doi:10.2307/3792640

Cited by 25 publications

(31 citation statements)

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“…To avoid difficulties in the detection and identification of Saksenaea in clinical samples, several authors have emphasized the need for special culture techniques, such as the use of floating agar blocks on water, or the use of BorelliЈs lactrimel agar (15,29) to induce sporulation. However, our use of these techniques yielded poor results (data not shown).…”

Section: Discussionmentioning

confidence: 99%

Molecular Phylogeny and Proposal of Two New Species of the Emerging Pathogenic FungusSaksenaea

et al. 2010

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Saksenaea is a monotypic genus belonging to the order Mucorales and capable of producing severe human infections. Through a polyphasic study based on analysis of the sequences of the internal transcribed spacer (ITS) region, domains D1 and D2 of the 28S rRNA gene, and the elongation factor 1␣ (EF-1␣) gene, as well as by evaluation of relevant morphological and physiological characteristics of a set of clinical and environmental strains, we have demonstrated that Saksenaea vasiformis is a complex of species. We propose as new species Saksenaea oblongispora, characterized by oblong sporangiospores and unable to grow at 42°C, and Saksenaea erythrospora, characterized by large sporangiophores and sporangia and by ellipsoid sporangiospores, biconcave in the lateral view. Itraconazole, posaconazole, and terbinafine were active against all isolates included in the study, while amphotericin B, voriconazole, and the echinocandins showed low activity.The genus Saksenaea S. B. Saksena, belonging to the subphylum Mucoromycotina, was first isolated from a forest soil in India (38). Saksenaea vasiformis S. B. Saksena, the only species of the genus, is a filamentous fungus reported in soil, driftwood, and grains (1, 12, 34), characterized by flask-shaped sporangia, short sporangiophores, oval sporangiospores, and dark rhizoids. It is a thermotolerant fungus that grows between 25°C and 44°C (13, 24, 44) and is able to cause severe human infections in both immunocompromised and immunocompetent hosts. Mucormycosis caused by S. vasiformis most often occurs after traumatic implantation of the fungus but can also be due to inhalation of spores (18), spider bites, insect stings, and the use of indwelling catheters (11,22,28,31). Clinical cases seems to be more common in tropical and subtropical climates than elsewhere and have been reported from Australia (16,19,22,40,48), India (6,7,11,33), the United States (1,8,31,35,45), Thailand (44), Tunisia (28), the Middle East (2, 25), and Central and South America (9, 47).Recent molecular studies, based mostly on internal transcribed spacer (ITS) sequences, which have proven to be a good phylogenetic marker in the Mucorales (5), have demonstrated unexpectedly high genetic diversity within the most relevant clinical species of this order (3,4,21). In the case of Saksenaea vasiformis, a few studies have also demonstrated relatively high intraspecific genetic diversity (9, 28), suggesting that more than one phylogenetic species may be present within this morphospecies.To identify possible cryptic species in S. vasiformis, we performed a polyphasic study, based on sequence analysis of three loci, and evaluated different morphological and physiological characteristics for a diverse panel of strains. MATERIALS AND METHODSFungal strains. A total of 11 strains from different reference culture collections were included in the study (Table 1) DNA extraction, amplification, and sequencing. For sequencing of the ITS region, DNA was extracted and purified directly from fungal colonies by following a sl...

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Section: Discussionmentioning

confidence: 99%

Molecular Phylogeny and Proposal of Two New Species of the Emerging Pathogenic FungusSaksenaea

et al. 2010

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“…Necrotizing fasciitis (284,288,322,376) and renal and bladder infections with this agent have also been described (85,258,342). Of the 18 patients with cutaneous infection, 17 have survived with appropriate treatment; the outcome for 3 additional patients is unknown (145,349). A. elegans is an uncommon cause of rhinocerebral disease in humans (76,376).…”

Section: Apophysomyces Elegansmentioning

confidence: 99%

“…Percutaneous routes of infection are also suggested by several other cases including postoperative surgical wound infections (256,284), an infection following an injection (77), and an infection following a spider or insect bite (494). Four cases of infection have no known mode of exposure, including one case where A. elegans was isolated from a bronchial washing (145), two cases with renal involvement with the fungus (85,342), and one case of osteomyelitis (295). Of the two cases of rhinocerebral infection with Apophysomyces, one was probably the result of traumatic implantation of spores (376) and the other probably resulted from inhalation of spores into the sinus (76).…”

Section: Apophysomyces Elegansmentioning

confidence: 99%

“…The use of the antibiotics in this situation may not have been a risk factor for acquiring the initial infection but may have played a role in promoting fungal growth in a preexisting infection. There was no mention of risk factors or patient disease characteristics for the patient from whom the bronchial wash isolate was obtained (145) or for two additional patients with subcutaneous abscesses (349).…”

Section: Apophysomyces Elegansmentioning

confidence: 99%

“…While most members of the Mucoraceae readily sporulate on standard media such as Sabouraud dextrose, cornmeal, or potato dextrose agar, Apophysomyces elegans, Saksenaea vasiformis, and Mortierella wolfii may produce only sterile hyphae under these routine culture conditions. Sporulation with these isolates may be stimulated using the technique described by Ellis and Ajello (145). Cultures initially grown on cornmeal-sucrose-yeast extract agar are starved by being transferred to 1% agar in water.…”

Section: General Culture Characteristics Of the Mucoralesmentioning

confidence: 99%

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