Please suggest easy and reliable method for identification of Malassezia species. Maybe there are biochemical tests available or sequencing similar to bacterial 16S rRNA sequencing? If yes, what primers should I use for PCR and for sequencing in that case?
Malassezia spp. are lipophilic unipolar yeasts recognized as commensals of skin that may be pathogenic under certain conditions. The genus Malassezia now comprises of seven species. Seventy skin scrapings from patients with pityriasis versicolor infection, positive in 10% potassium hydroxide (KOH), were cultured onto modified Dixon's agar (mDixon's agar) and Sabouraud dextrose agar (SDA) and incubated at 32 degrees C. Speciation was done on the basis of Gram stain morphology, catalase test, and utilization of Tweens. Out of 70 scrapings 48 (68.75%) showed growth on mDixon's agar. The commonest isolate was M. sympodialis (28, 58%) followed by M. globosa (19, 40%) and one isolate was (2%) of M. restricta. M. sympodialis was the commonest species affecting our population and there was no isolation of M. obtusa, M. slooffiae, M. pachydermatis and M. furfur.
Culture methods are very limited for recovery of Malassezia spp. and are pretty useless for quantitative estimates. Not sure why Sabouraud dextrose is mentioned - the only Malassezia that could potentially grow on it would be M. pachydermatis. Evelyn Gueho described some tests in the 90's(in http://link.springer.com/article/10.1007/BF00399623 and a few subsequent papers) but suggest you're much better off with molecular techniques as in http://mmy.oxfordjournals.org/content/54/3/232.full
Hi Ruzauskas,
DNA sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) regions of rRNA, followed by comparative sequence analysis, has been the ‘gold standard’ for molecular identification of most fungi, but there are an easy procedure for detection of some common species of Malassezia by nested PCR at the ITS Region of the rRNA Gene as follow: (Mahmoudabadi et al, 2014)
first PCR step for ITS region: ITS1F-N GGATCATTAGTGATTGCCTTTATA & ITS4R TCCTCCGCTTATTGATATG
Second PCR step:
M. furfur (230bp): M. f-F CTACTCGCGTACAACGTCTCTG & 5.8S-R TTCGCTGCGTTCTTCATCGA
M. globosa (270bp): M.gl-F CAATAAGTGTGTCTCTGCGG & 5.8S-R TTCGCTGCGTTCTTCATCGA
M. restricta (320bp): M. rt-F CTTGGTTGGACCGTCACTG & M. rt-R AGGCGGATGCAAAGTGTCTC
good luck....................
Dear Hayder,
Thank you so much. That's the answer I have expected! (I guess just the forward primer of M. restricta at the end lacks of one "G"...)
Hi Ruzauskas, you can check the original paper, Mahmoudabadi et al., (2014 ) Jentashapir J Health Res. December; 5(6).......
all the best.......
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