O C C U R R E N C E O F D E R M A T O P H Y T E S I N B A N G K O K , T H A I L A N D

R. L. TAYLOR, * RENOO KOTRAJARAS and VIN1TA JOTISANKASA

Department Bacteriology and Mycology, S E A T O Medical Research Laboratory, Bangkok, Thailand, Women's Hospital, Bangkok, Thailand and Department of Medical Sciences

Laboratory, Bangkok, Thailand

Cultures for pathogenic fungi were obtained from 1372 predominantly adult residents of Bangkok presenting lesions resembling cutaneous candidiasis or dermatophytoses. The organism most frequently isolated was Candida albicans (38.1%), followed by Trichophyton rubrum (34.9%), T. mentagrophytes (14-8%), Epidermophyton floccosum (7-2%), Microsporum cani~ (1'8%), M. gypseum (1'8%), T. tonsurans (0"9%), M. audouinii (0.5%) and 7-. concentricum (0.2%). C. albicans, 7-. rubrum and T. mentagrophytes represented 88% of the isolates obtained from all lesions. Tinea corporis was the most prevalent disease, with tinea pedis, tinea cruris, tinea unguium, tinea marius, tinea capitis and oral thrush occurring with decreasing frequency.

Between N o v e m b e r 1965 and Sep tember 1967, a s tudy was conduc ted to determine the prevalence of dermatophytoses , cutaneous candidiasis a n d the distribution of the causative agents a m o n g pat ients seen in the D e r m a t o l o g y Clinic of W o m e n ' s Hospital , Bangkok, Tha i l and . La te in 1966, pat ients seen at 2 additional hospitals (Tobacco M onopo l y and Bangrak) were inc luded to provide a bet ter sampl ing of the male popula t ion and to ob ta in da ta on individuals f rom a wider range of socio-economic levels.

MATERIALS AND METHODS

One day each week clinical material was collected from patients who showed signs even remotely resembling a dermatophytosis. Cultures were made from the area of the lesion, after first cleansing with 70% alcohol, by collecting appropriate samples of hair, skin or nail and planting these specimens directly onto duplicate plates of Sabouraud's-chloramphenicol-cycloheximide agar.~" The plates were sealed with paper tape to reduce contamination and dehydration, incubated at 25°C., and periodically examined for 30 days. Blood agar plates were also inoculated and incubated at 37°C., if the appearance of the lesion suggested either a pr imary or secondary bacterial infection.

Dermatophytic fungi were identified initially on the basis of their gross and microscopic morphology. When applicable, differentiation of the Trichophyton spp. was verified by nutritional tests (Georg & Camp, 1957). Isolates of 7". rubrum and T. mentagrophytes were tested for their capability to perforate sterilized human hair in vitro (Ajello & Georg, 1957). Chlamydospore production on rice extract agar containing 1% Tween 80 was used to identify Candida albicans. However, all isolates were further verified by carbohydrate assimilation patterns using dextrose, galactose, lactose, maltose, raffinose, sucrose and cellobiose (Ajello, Georg, Kaplan & Kaufman, 1963).

*Present Address: Department of Microbiology, University of Texas Medical School, San Antonio, Texas, 78229.

tMycosel agar--Baltimore Biological Laboratory. 307

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308 1~. L. TAYLOR, R. KOTRAJARAS AND V. JOTLSANKASA

No attempt was made to enumerate the superficial tinea versicolor infections which were frequent but not the primary complaint among patients seen in the clinics.

RESULTS

Cultures were obtained from 1372 predominantly adult persons (812 females, 560 males) and fungi recovered from approximately 559 (41%).

The most frequently isolated organism was C. albicans (38.1%), followed by T. rubrum (34.9%), 7-. mentagrophytes (14.8%), Epidermophyton floccosum (7.2 %), M. canis (1.8%), M. gypseum (1.8%), T. tonsurans (0.9%), M. audouinii (0.5%) and 7". concentricum (0.2 %). The frequency and distribution of lesions and the causative mycotic agents are shown in Table1.

Two organisms were the principal agents isolated from lesions found in each of the geographic areas of the body listed in Table 1. C. albicans was the most frequent causative agent of infections of the nails, feet, groin and oral cavity, and T. rubrum the principle cause of body, hand and scalp infections.

The types of infections seen in males and females were essentially the same, with 2 exceptions. Infections of the feet were more frequently observed among the males (males, 39.4 % ; females, 17.5 %), whereas, infections of the nail and paronychia were more common among females (males, 3.2 %; females, 14.9 %).

Several atypical organisms were encountered during the course of this study. An unusual strain of M. canis, having characteristics of both M. canis and M. audouinii, was recovered from 4 persons exhibiting typical ringworm lesions. A series of Microsporum isolates previously recovered from gibbons (Taylor, unpublished data), but having the same colonial and microscopic characteristics, were sent to Drs. L. Ajello and Irene Weitzman for identifica- tion. These organisms, which have a gross colonial morphology more like M. canis than M. audouinii but produce few or no macroconidia and grow poorly on rice, were considered to be dysgonic strains of M. canis. The organisms recovered from humans were likewise considered to be within the range of the generic characteristics of M. canis, although differentiation from M. audouinii was difficult. Approximately 5 % of the 7". rubrum isolates were characterized by a zone of bright yellow pigment at the periphery of the colony. The typical dark red pigment which developed as the colony matured was restricted to the center of the colony. Colonial and microscopic morphology of these isolates were otherwise typical.

Discussion

The results of this study clearly indicate the significance of C. albicans and 7-. rubrum as causative agents of superficial infections in this tropical community.

These 2 organisms constitute 73 % of our isolations and if T. mentagrophytes, the third most frequently recovered fungus, is included, these 3 organisms account for 88 % of the isolates obtained from all lesions. Since candidiasis (38 %) and lesions caused by the filamentous fungi do not respond to the same therapeutic regimen, laboratory support becomes essential to establish this differentiation of causative agents.

7-. rubmm was isolated 2.5 times more frequently than 77. mentagrophytes,

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TAB

LE 1

.--D

ISTR

IBU

TIO

N A

ND

PRE

VA

LEN

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F SU

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ICIA

L MY

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S AN

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559

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(Nov

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65 to

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195 83

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310 R . L . TAYLOR, R. KOTRAJARAS AND V. JOTISANKASA

confirming similar findings observed in many areas of the world. In the 2 previous studies conducted in Bangkok, Vibulyasekha & Vathanabhuti (1963) reported an even greater preponderance of 7-. rubrum over T. mentagrophytes (4 to 1), whereas, Nissaisorakarn (1967) found a reverse relationship with T. mentagrophytes isolates outnumbering T. rubrum 2 to 1. The explanation for this discrepancy is not readily apparent since both studies were conducted in the same hospital. When comparing results between studies, caution and qualifica- tions must be used due to the differences in test populations which can greatly influence the results. Age, occupation, general health status and geographic area are some of the factors known to influence the frequency and kinds of disease, as well as the type of causative organisms found in a survey. All of these factors were operative in this study including the probability that the inhabitants of Bangkok are not entirely representative of other neighboring geographic areas. An example of the influence of geographic areas is the pockets of endemicity for 7". concentricum which are known to exist throughout Thailand but not represented in our study. The effect of age is perhaps best illustrated by the low percentage of scalp infections found among our adult group as compared to the expected numbers in a younger more susceptible age group. The influence of occupation and/or sex on the types of infection is clearly illustrated by the preponderance of nail and paronychia infections among women and the greater number of infections of the feet of males. Since all clothing and eating utensils are hand washed, many of the women in Thailand often have their hands in water frequently for extended periods. The maceration resulting from such exposure is predisposing to candidiasis and probably explains the 5 to 1 preponderance of nail infections seen in females. Many of these infections were seen among the wash amahs and other persons earning their livelihood from occupations requiring prolonged immersion of their hands in water.

The unequal distribution of tinea pedis between males and females (2 to 1) can perhaps be attributed indirectly to occupation and directly to the require- ment for wearing shoes. In a society that prefers not to wear shoes, and in fact does not wear shoes in the home, the persons required to wear shoes for the longest periods of time are the professional men, those involved in commercial enterprises and soldiers. It is among these persons that the majority of the mycotic infections of the feet occur.

A comparison of the data from this investigation with those reported by Nissaisorakarn (1966, 1967) show a reasonable correlation considering the differences in the 2 study populations. Our group was predominantly adult with a 1 to 1.5 ratio of males to females while her population was predominantly male (4 to 1) and also included a younger age group. In both studies tinea corporis was the most prevalent disease followed by tinea pedis, tinea cruris, tinea unguium and tinea capitis. There were slight differences in percentages of these diseases between the 2 studies, the most evident being the 8.8 % tinea capitis reported by Nissaisorakarn versus 2.8% in our study. There were also differences in the prevalence of the various fungi. Most differences were minimal with the exception of the reverse relationship between the isolates of 7". rubrum

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DERMATOPHYTES IN THAILAND 311

and T. mentagrophytes which was mentioned above. Not enough data are avail- able from the survey by Vibulyasekha & Vathanabhuti (1963) to make any comparison other than their reported 5 to 1 isolation ratio of 7". rubrum and T. mentagrophytes.

RESUMEN

Se hicieron cultivos para hongos patdgenos de 1372 residentes de Bangkok, principalmente adultos, los cuales presentaban lesiones pareeidas a candidiasis cutdmea o dermatofitosis. El agente m~s frecuentemente aislado fue C. albicans, 38.1%, seguido por 7-. rubrum, 34"9%; 7-. mentagrophytes, 14'8°/o; E. floccosum, 7"2%; M. canis, 1-8%; M. gypseum, 1"8%; 7-. tonsurans, 0'9%; M. audouinii, 0.5% y T. concentricum, 0.2%. E1 88% de los agentes aislados a partir de todas las lesiones fueron C. albicans, T. rubrum y 7-. mentagrophytes. La enfermedad m~ts comfin fue tinea eorporis, seguida de una manera deereciente por tinea pedis, tinea cruris, tinea unguim, tinea manns, tinea capitis y estomatitis micdtica.

ACKNOWLEDGEMENTS

We wish to express our thanks to the Mesdames Yupin Charoenvit and Malinee Thamrongnavasa- wat for their competent technical assistance and to Senor J. Ribas for providing the Spanish translation of the summary.

REFERENCES

AJELLO, L. & GEORO, LUClLLE K. (1957). In vitro hair cultures for differentiating between atypical isolates of Trichophyton mentagrophytes and Trichophyton rubrum. Mycopath. Mycol. appl., 8, 3-17.

AJELLO, L., OEORG, LUCILLE K., KAPLAN, W. & KAUFMAN, L. (1963). Laboratory Manual for Medical Mycology. Pp. E-17 & E-24. U.S. Govt. Printing Office.

GEORG, LUClLLE K. & CAMP, L. B. (1957). Routine nutritional tests for the identification of dermato- phytes. J . Bact., 74, 113-121.

NISSAISORAKARN, MALEE (1966). Dermatophytes in Thailand. Royal Thai Army Med. J. , 19, 221-226. NlSSAISORAKARN, MALEE (1967). Cutaneous candidiasis in Thailand. Royal Thai Army Med. J. ,

20, 26-33. VmULYASEKHA, S. & VATHANABHUTI, S. (1963). Personal communication.

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