Penicillium marneffei: types and drug susceptibility

The PCR fingerprints of 30 Penicillium marneffei isolates from Chiang Rai in northern Thailand and Bangkok in central Thailand were studied through use of single-nucleotide primers (GACA)₄ and the phage M13 core sequence. Discrimination of fingerprint patterns was based on differences in the number of major bands. The P. marneffei isolates were divided into four types, i.e., A, B, C, and D. Type A was found in two isolates from Chiang Rai (6.7%). Types B and C respectively were found in two (6.7%) and one (3.3%) isolates from Bangkok. The predominate type D (83.3%) was found in isolates obtained from Chiang Rai and Bangkok. The PCR fingerprinting method was found to be useful for the epidemiological study of P. marneffei, a dimorphic opportunistic fungus and an emerging pathogen in the HIV pandemic. In vitro drug susceptibility testing by broth macrodilution to four antifungal agents against the yeast form ofP. marneffei was performed. The MIC ranges for amphotericin B, fluconazole, itraconazole, and ketoconazole were 0.125–0.5, 4.0–8.0, <0.032, and <0.125 μg/ml respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Usefulness of a microimmunodiffusion test for the detection of Penicillium marneffei antigenemia,antibodies, and exoantigens

Eight sera from culturally-proven cases of penicilliosis marneffei and their corresponding isolates were examined for circulating antibody(ies) and antigen, and exoantigens, respectively, using a microimmunodiffusion (MID) test. Two of the 8 sera produced strong precipitins (1-2) when reacted against control Penicillium marneffei antigen (5-week-old shaken cultures at 25 C) in the presence of control rabbit anti-P. marneffei serum. Five of the 8 sera produced a strong precipitin line when reacted against control hyperimmune serum to P. marneffei. These five sera, and one additional serum, which tested negative for antibody to P. marneffei, demonstrated the presence of antigen by reacting only against the anti-P. marneffei serum. Serological evaluations of the sera revealed that the MID test is capable of detecting antibody and antigen in AIDS patients having penicilliosis marneffei infections. Exoantigen analysis of the 8 P. marneffei isolates, which were previously identified using this conventional and time-consuming macro- and micro-morphological characteristics, showed the presence of 1 to 4 specific exoantigens in MID. With the exoantigen analysis, the identity of all of the isolates was confirmed as P. marneffei. Our studies indicated that the serological tests are useful for detecting circulating antibody and/or antigen in patients' sera, and that the exoantigen test is reliable for confirming the identity of P. marneffei cultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

A study of dermatophytoses in Bangkok (Thailand)

A total of 719 cases of dermatophytoses was studied in the Division of Dermatology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, during January to December 1986. Infection caused by fungus comprises 12%, while the incidence of dermatophytoses was 5.5% of skin disorders. The age group commonly infected was 12–21 years old (mean age of 18 years); 40% was female and 47.5% was male. In the female patients the common prevalent infections were tinea corporis 29%, tinea cruris 23%, tinea pedis 16%, while in male patients it was 28%, 39% and 14% respectively. Only 4 species of dermatophytes were isolated. The prevailing ones were: Trichophyton rubrum 66%, T. mentagrophytes 15%, Epidermophyton floccorum 13% and Microsporum gypseum 6%.     

Immunodiffusion test for diagnosing human pythiosis

An immunodiffusion test was developed for diagnosing subcutaneous and systemic pythiosis in humans. When culture filtrate antigen (CFA) from P. insidiosum was reacted against patient and rabbit antisera, 1–5 precipitin bands occured both in patient and rabbit antisera, and a line of identity also occured between patient and rabbit sera. When control P. insidiosum CFA was reacted with 30 apparently normal persons, 20 Thalassemia patients, 2 candidosis and 5 aspergillosis patients, no precipitin bands were found. P. insidiosum CFA also tested with rabbit antibodies to B. dermatitidis, C. immitis, H. capsulatum, P. brasiliensis, C. albicans, M. furfur and A. fumigatus revealed no cross reactions. This test is practical, sensitive and specific.     

A study of pityriasis versicolor in Bangkok (Thailand)

A total of 410 cases of pityriasis versicolor were studied in the Division of Dermatology, Department of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand, during January to December 1987. These comprised 1% of all skin disorders, while infection caused by fungus comprised 17%. Most persons infected with pityriasis versicolor were 12–21 years old (mean age 20 years) and 47% were male and 53% were female. The common sites of infection were back, arms, face and trunk. The colors of lesions found were white (83%), brown (7%), pink (6%) and ashy (4%). Both forms of M. furfur were isolated, the ovale form in 97% and the orbiculare form in 3% of cases. The colors of the lesions did not depend on the form of the organism. Mycological and immunological studies confirmed that the two forms were different stages in the complex developmental cycle of a single species.     

Clinical and environmental isolates of Cryptococcus neoformans in Bangkok (Thailand)

Cryptococcus neoformans was isolated from 13 patients (7 females and 6 males) suffering from systemic cryptococcosis. Eight patients were suffering from central nervous system cryptococcosis and 5 were suffering from disseminated cryptococcosis. Systemic lupus erythematosus was found to be the common underlying disease in 3 patients. The results of treatment depended on the underlying diseases (7 improved, 6 died). Also, 13 isolates of C. neoformans were obtained from feces of 30 pet birds. All 26 isolates of C. neoformans were cultured in glycine cycloheximide medium and were found to be of serotypes A and D.     

Immunodiffusion test for diagnosing basidiobolomycosis

An immunodiffusion test was developed for the diagnosis of basidiobolomycosis. When culture filtrate antigen (CFA) from Basidiobolus ranarum was reacted against two human patient and two rabbit antisera, 2 precipitin bands, inner (N) and outer (Y), were revealed for both patient and rabbit antisera. A line of identity was also observed between precipitin bands obtained with patient and rabbit sera. When CFA from B. ranarum (B CFA) was reacted against rabbit sera which contained antibody to Conidiobolus coronatus and Pythium insidiosum, 1 precipitin band corresponding to inner band (N) was observed. This finding showed that B. ranarum, C. coronatus and P. insidiosum shared at least one common antigen. After B CFA was absorbed with Pythium rabbit antiserum, the inner precipitin line that occurred between B CFA and rabbit antisera of Pythium and Conidiobolus disappeared. However, with Basidiobolus rabbit antiserum, the result did not change. The antigens which could be demonstrated by inner (N) and outer (Y) precipitin bands were heat stable at 56 ° C for 30 min. The titer of the antibodies specific to these antigens decreased as the lesions subsided. When B. ranarum CFA was reacted against sera from 20 apparently normal persons, 20 diabetes mellitus patients, 5 aspergillosis patients, 2 candidosis patients and 3 pythiosis patients, no precipitin band was found. B. ranarum CFA was also treated with each rabbit antiserum specific to Candida albicans, Malassezia furfur and Aspergillus fumigatus. No precipitin bands occurred with any of these antisera. Thus, this test was found to be practical, sensitive and specific, and can be used to monitor patients infected with Basidiobolus ranarum.