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Where differences occurred these were single category
disagreements (i.e. never a mismatch of S against R).
Testing clinical isolates of Trichophyton spp. was possible
within 16 hr.
The method is simple, low cost and versatile and can be
adapted to new species and antimicrobials. Additionally,
the potential for PAO to be microengineered 2 suggests
further applications in clinical microbiology can be
developed.
References
1. Ingham CJ, Ende M van den, Wever PC, Schneeberger
PM. J Med Microbiol 2006;55:1511-9.
2. Ingham CJ, Sprenkels A, Bomer J, Molenaar D, Berg A
van den, Hylckama Vlieg JET van, et al. Proc Natl Acad
Sci USA 2006;46:18217-22.
O077
The use of chromogenic media in medical mycology
I.M. Curfs-Breuker, J.F.G.M. Meis
Dept. of Medical Microbiology, Canisius Wilhelmina Hospital,
Nijmegen
Purpose: Because of rising incidence of candidiasis, the
high morbidity and mortality in immunosuppressed
patients with systemic fungal infections and the variation
in antifungal susceptibility of non-Candida albicans
species, the need for rapid differentiation and identification
of yeasts in mixed cultures is desirable. Several
chromogenic media have been developed; on these media
the yeast colonies have strongly contrasting colours
produced by reactions of species-specific enzymes with
proprietary chromogenic substrates.
The purpose of this study was to compare CandiSelect 4
(Bio-Rad, CS4) and Chromogenic Candida agar (Oxoid,
CCA) with CHROMagar Candida (ITK Diagnostics B.V.,
CHROM).
Methods: 400 clinical samples (sputa, BAL, swabs of
throat, nose, ear and mouth, mouthwashes) were cultured
on CS4, CCA and CHROM, incubated at 30 o C and daily
examined, according to the manufacturers instructions,
for 7 days. During examination special attention was
paid to clear difference and intensity of the colours and
the capability to suppress the growth of bacterias. For
yeast identification the germ tube test and Auxacolor 2 ®
were used. The results of CS4 and CCA were compared
to CHROM.
Results:
Compared to CHROM:
- equal score on CS4 in 354 and on CCA in 350 cases
- lower score on CS4 in 16 and on CCA in 24 cases
- better score on CS4 in 25 cases and on CCA in 21
cases.
Ned Tijdschr Med Microbiol 2008;16:Supplement
S32
Findings on CS4 and CCA:
- colony colours specific for Candida albicans on CS4 and
CCA were identified as C. albicans. Of all other colony
colours no strain was identified as C. albicans.
- the examination of similar colours is subjective
- poor discrimination between light blue and light blue
with turquoise centre on CS4 after an incubation time
of 5-≥7 days
- sporadic or no growth of resistant gram-negative rods.
Findings on CS4:
- C. albicans colour is the clearest and most discriminating
of all chromogenic media
- making difference between the colours of Candida
tropicalis and Candida krusei is difficult
- the C. tropicalis colour is identified as Saccharomyces
cerevisiae in 4% of all cases
- discriminating ability is lost when medium is exposed
to light ≥8 hours.
Findings on CCA:
- the C. tropicalis colour is identified as S. cerevisiae in 5%
of all cases
- yellow/beige colonies are difficult to observe
- no large discrimination between green and light blue
colonies on CCA after an incubation time of 5-≥7 days.
Conclusions: CS4 has the widest differentiating ability and
a discriminating colour for Candida glabrata. On CS4 and
CCA the colours of C. albicans are unique to C. albicans,
blue and green colony colours are undistinguishable after
a long incubation time and the capability to suppress the
growth of bacteria.
O078
Separation of species of Fonsecaea on the basis of genealogical
concordance phylogenetic species recognition (gCPSR)
M.J. Najafzadeh 1,2,3 , H. Badali1,2 , A.H.G. Gerrits van den
Ende1 , G.S. de Hoog1,2 1 2
Fungal Biodiversity Centre, Utrecht, Institute for Biodiversity
and Ecosystem Dynamics, University of Amsterdam; 3Dept. of
Mycology, Mashhad University of Medical Sciences, Mashhad,
Iran
A multilocus sequence typing (MLST) system based on
sequence analysis of the ribosomal internal transcribed
spacers (ITS), b-tubulin (BT2) and actin (ACT) regions
was performed in 38 strains morphologically identified
as Fonsecaea and originating from clinical and environmental
sources in Central and South America, Africa,
East Asia and Europe. Elongation factor 1-alpha (EF1)
could not be amplified. Based on the sequences of ITS,
strains of Fonsecaea were classified into three major
clades: a group representing Fonsecaea pedrosoi, a group
representing Fonsecaea monophora, and an intermediate
group. The same grouping was found with ACT and BT2.