Clinical And Laboratory Study Of Microsporum Canis

Objective: Microsporum Canis is an important zoophilia dermatophytes. Microsporum Canis usually become one important etiological factor of tinea capitis and tinea corporis. In order to understand the differences between Microsporum Canis strains isolated from tinea capitis and tinea corporis, morphological and physiological of Microsporum Canis strains isolated from tinea capitis and tinea corporis were compared with the results of the activities of extracellular enzymes by Microsporum Canis, in vitro hair perforation, the quantity of DNA in cells and the proliferation indices of the cells of Microsporum Canis.Methods: The strains of Microsporum Canis were isolated from suspected dermatomycoses, which were demonstrable by microscope and culture and were cultured at 27 ℃ on Sabouraud agar. Propagation of the strains of Microsporum Canis were carried out every month, which were stored at -4℃. Twenty strains from the Microsporum Canis were chosed and divided into groups, group tinea capitis of which were ten strains of the Microsporum Canis strains isolated from tinea capitis and groups tinea corporis of which were ten strains of the Microsporum Canis strains isolated from tinea corporis.The activities of lipase by group tinea capitis and group tinea corporis were observed at 2 days after the inoculum was deposited on lipase medium. The activities of Serine enzyme by group tinea capitis and group tinea corporis were observed at 7 days after the inoculum was deposited on Serine enzyme medium. The diameter of the colony and halo around the colony could be measured. The diameter of the colony was the numerator and the diameter of halo around the colony was the denominator, ratio of which could be taken. The number of the ratio meaned the activities of lipase or Serine enzyme by group tinea capitis or group tinea corporis. If the number was much, the activities of lipase by group tinea capitis or group tinea corporis was considered low, while if the number was few, the activities of lipase by group tinea capitis or group tinea corporis was considered high. In vitro hair perforation test, healthy hair of 4 different age groups (less than 2 years old, 2~13 years old, 13-19 years old, older than 19 years old) were collected. The suspension of the Microsporum Canis isolates from tinea capitis or tinea corporis incubated on the surface of the hair on modified Sabouraud agar at 27T? and observed erevy day after 3days under light microscope (LM) and electronic microscope (SEM). Single Microsporum Canis cell liquor was made. One staining of ethidum bromide(EB) was used to stain the cells and CRBC as internal parameter standard to assay total DNA per cell. Group tinea capitis and group tinea corporis were analysed with FCM. The data of activities ofextracellular enzymes by group tinea capitis or group tinea corporis and the proliferation indices were processed by two-sample t-test for independent samples in SPSS 10.0 statistical software. P value of less than 0.05 was considered to be statistically significant.Results: Microsporum Canis infection was demonstrable by microscopy and culture. 28 strains of Microsporum Canis isolated from patients; 16 cases were male, the other 12 cases were female, male was major than female. There were 16 cases of tinea capitis (57.1%), 10 cases of tinea corporis(35.7%) and 2 cases of tinea pedis(7.2%).The Mean of the activities of Serine enzyme of group tinea capitis was 0.810, which was less than that of group tinea corporis. The Mean of the activities of Serine enzyme of group tinea corporis was 0.849. By t-test, the activities of Serine enzyme of group tinea capitis and group tinea corporis was very different, which was statistical significance (P <0.01). While, The Mean of the activities of lipase of group tinea capitis was 0.834, which was less than 0.843 of group tinea corporis. The activities of lipase of the group tinea capitis and group tinea corporis were little different, which were no statistical significance (P > 0.05).After inoculation, there was about 5-10 days for Microsporum Canis to make damage to the hair. It was known that the Microsporum Canis isolates from tinea capitis damage the hair earlier than those from tinea corporis by usually...