Clinical significance and molecular characterization of non sporulating moulds isolated from patients with bronchopulmonary mycoses with special reference to basidiomycetes.

Ref ID: 19371

Author:

S. Kathuria,1 K. Agarwal,1 P. Singh,1 J. F. Meis2 and
A. Chowdhary1

Author address:

1V.P.Chest Institute, Delhi, India and 2Department of Medical
Microbiology, Radboud University Nijmegen Medical Center, the
Netherlands

Full conference title:

6th Trends in Medical Mycology 2013

Date: 11 October 2014

Abstract:

Objective Non sporulating moulds (NSM) have predominately been
reported as human pathogens in immunosuppressed patients. Their
definitive identification using conventional methods is problematic as
many isolates remain sterile in culture. Thus inconclusive culture
reports might adversely affect treatment strategies. The clinical signif-
icance of NSM in pulmonary mycoses is poorly understood. In this
study, we investigated NSM originating from the respiratory tracts of
patients with chronic respiratory ailments by phenotypic methods
and sequencing of ITS and D1/D2 regions. Furthermore, the clinical
significance of these moulds was determined through the outcomes
of the cases.
Methods A total of 4,948 respiratory specimens, during Jan. 2010-
May 2013 were investigated. The moulds that failed to sporulate
after one week of incubation on Sabouraud glucose agar at 28°C
were taken further for identification by slide cultures on potato dex-
trose agar (PDA) and sequencing of ITS and D1/D2 region of rDNA.
For sporulation they were cultured on PDA and on decayed wood for
4 weeks at 28°C with periodic light exposure. Antifungal susceptibil-
ity was performed for azoles, amphotericin B and echinocandins with
modified CLSI microbroth dilution method.
Results Fifty two NSM were isolated from 47 patients. Of these 50
were presumptively identified as basidiomycetes based upon spicules
and hyphal pegs and 2 as ascomycetes which showed only vesicles.
Of 50 probable basidiomycetes, 39 showed clamp connections. Five
isolates showed basidiocarp formation. ITS and D1/D2 sequencing
confirmed 27(52%) as Schizophyllum commune, 11(21.1%) Ceriporia
lacerata, 4(7.6%) Porostereum spadiceum, 3(5.7%) Phanerochaete stereo-
ides, 2(3.8%) Neosartorya fischeri and one(2.0%) isolate each of Mar-
asmiellus palmivorus and Perenniporia species. Three(6%) remained
unidentified. Species level identification was achieved in 92% NSM.
Notably, only 72% isolates could be identified by ITS sequencing
whereas D1/D2 identified 92% isolates.
Barring invasive pulmonary mycosis (IPM), basidiomycetes (96%)
were the sole NSM in three patient groups namely those with allergic
bronchopulmonary mycosis (ABPM), fungal balls and only as colo-
nizer. In the group of IPM, 18% cases were due to the ascomycete N.
fischeri. S. commune was a colonizer in 60% of cases followed by C. lac-
erata (25%) and P. spadiceum (10%). ABPM due to S. commune was
observed in 8 cases. S. commune fungal ball were noted in 3 cases and
Perenniporia spp. in a solitary case. Patients with fungal pneumonia,
ABPM and fungal balls were treated with either voriconazole, itraco-
nazole or amphotericin B. However, 67% of the fungal pneumonia
patients on treatment expired. Posaconazole exhibited excellent in vi-
tro activity followed by isavuconazole, itraconazole, voriconazole and
amphotericin B. Caspofungin MECs ranged from 0.125-8 lg/ml.
Conclusions This study highlights the relevance of NSM in the clini-
cal context demonstrating the importance of basidiomycetes from
bronchopulmonary mycoses. Although these mould were most fre-
quently identified as asymptomatic colonizers in patients with pulmo-
nary problems, it is important to follow-up such patients in order to
prevent subsequent lung damage. Therefore, the need for identifying
and timely instituting antifungal therapy against environmental bas-
idiomycetes can hardly be overemphasized.

Abstract Number: o4.5

Conference Year: 2013

Link to conference website: NULL

New link: NULL

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