Evaluation of various carbon sources on conidia production among clinical isolated moulds

Abstract number: 1733_662

Santanirand P., Thanavanitnam S., Chongtrakool P., Angkananukool K.

Differentiation of conidia structure is one of the keys for fungal identification. The conventional slide culture technique has difficulty in certain culture conditions particularly in humidity levels which lead to uncertainty in sporulation. A new slide culture technique performed in 24-well tissue culture plate was introduced in order to overcome previous limitations. It showed several advantages over the conventional method, including simplicity and convenience in procedures, using less time and space, better humidity control and higher safety for workers. The latter advantage was due to double-coverglass technique. Apart from the adaptation of slide culture technique, the correlation of sporulation time and colony size or incubation period was studied. Fifty seven isolates of dermatophytes and forty eight black moulds from 16 genera were tested. In dermatophytes, approximately 90% of the isolates produced conidia when colony diameter reached 3 cm. which was equally to 7 days of incubation. For rapid and slow grower black moulds, the colony diameter of 1.4 cm. (or 5 days of incubation) and 6 cm. (or 6 days of incubation), respectively, were the optimal sporulation time. Lastly, the effect of various carbon sources on sporulation was studied. Among various flours, rice, brown rice and glutinous rice have showed the most promise in inducing conidia production. Therefore, these 3 flours were combined in a new media called triple flours agar (TFA). A comparison of TFA and potato dextrose agar and Sabouraud dextrose agar (SDA) in the dermatophyte group showed no differences but TFA was significantly better than SDA in the induction of sporulation in black moulds. Addition of fatty acids into TFA did not enhance induction capacity of sporulation in black moulds and dermatophytes. However, Nigrospora spp. responded to fatty acids addition by producing of significantly larger amount of conidia compared to TFA alone.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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