Physiological Characteristics of Environmental Isolates of Pathogenic Dematiaceous Fungi

Abstract

Summary: A total of 39 environmental isolates of pathogenic dematiaceous fungi (Fonsecaea pedrosoi: 14 isolates, Phialo‐phora verrucosa: 6, Cladosporium carrionii: 9, Exophiala jeanselmei: 2, Ramichlo‐ridium subulatum: 6, Cladosporium tenuis‐simum: 1 and Phaeoisaria clematidis: 1) were evaluated for their various physiological characteristics including the ability to produce extracellular enzymes. Significant physiological characteristics included the ability of isolates of all the species except C. tenuissimum to decompose tyrosine, lyse human red blood cells, conversion of R. subulatum from filamentous to yeast form when cultured on Czapek‐Dox agar and also on blood agar and the growth of C. tenuissimum on Sabouraud dextrose agar incorporating 3.6 M NaCI. Isolates of all the species except those of C. carrionii produced lipase, while only the isolates of P. verrucosa, E. jeanselmei and Ph. clematidis were positive for phospholipase. Zusammenfassung: An 39 UmgebungsisoIaten pathogener Schwarzepilze (Fonsecaea pedrosoi: 14 Isolate, Phialophora verrucosa: 6, Cladosporium carrionii: 9, Exophiala jeanselmei: 2, Ramichloridium sub ulatum: 6, Cladosporium tenuissimum: 1, Phaeokaria clematidis: 1) wurden physiologische Eigenschaften, darunter auch Exoenzym‐Aktivitäten, untersucht. Signi‐fikante physiologische Eigenschaften be‐trafen die Fähigkeit des Tyrosin‐Abbaus und die Erythrozyten‐Lyse bei allen un‐tersuchten Arten außer bei C. tenuissimum, die Konversion von R. subulatum von der Filamentform in die Hefephase auf Czapek‐Dox und Blutagar sowie das Wachstum von C. tenuissimum auf Sabouraud‐Glucose‐Agar mit 3.6 M NaCl‐Zu‐satz. Sämtliche Isolate außer C. carrionii zeigten Lipase ‐Aktivität. Phospholipase wurde nur bei P. verrucosa, E. jeanselmei und Ph. clematidis gefunden.

Secretion of five extracellular enzymes by strains of chromoblastomycosis agents

“…These results are in agreement with those observed in dematiaceous fungi 17 . Urease is a metalloenzyme that catalyzes the hydrolysis of urea to ammonia and carbamate.…”

“…The enzymatic characterization of clinical isolates of chromoblastomycosis agents is important due to the fact that few studies have focused on this subject 14,17,44 . In the present study, we investigated the activity of five hydrolytic enzymes of 11 strains of chromoblastomycosis agents.…”

Virulence markers of opportunistic black yeast in Exophiala

“…Consistent with our findings, phospholipase activity was not detected in a strain of E. jeanselmei from case of human chromoblastomycosis . However, Gugnani and Okeke evaluated 39 environmental dematiaceous opportunists and found positive phospholipase activity in two E. jeanselmei isolates.…”

“…in group A Streptococcus and in Cryptococcus . Urease enables the utilisation of urea as a nitrogen source and has been reported as an extracellular enzyme produced by dematiaceous fungi . Vicente et al .…”

Physiological characteristics of clinical isolates of Hendersonula toruloidea and Scytalidium species

“…However, these criteria are not applicable to some fungi due to variations among isolates of the same species [8]. A study of physiological characteristics of certain dematiaceous fungi by Gugnani & Okeke [23] showed that Cladosporium carrionii could be distinguished from morphologically related C. tenuissimum by the ability of the former to grow at 37 "C, hydrolyse tyrosine, haemolysis, salt tolerance and production of lipase. Likewise Exophiala jeanselmei can be differentiated from closely related Ramichloridium subulatum on the basis of growth at 37"C, haemolysis and phospholipase activity.…”