Oral Diseases (1999) 5, 269 1999 Stockton Press All rights reserved. 1354-523X/99 $15.00

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GUEST EDITORIAL

Penicillium species—the good and the ugly

LP Samaranayake

Oral Bio-sciences, Faculty of Dentistry, University of Hong Kong, Hong Kong

The genusPenicillium is an ubiquitous garden varietyfungus (.200 identified species), abundant in nature, andthey are common laboratory contaminants. Indeed the firstantibiotic, penicillin, discovered by Alexander Fleming in1929 was derived from such a laboratory contaminant—Penicillium notatum. While the products of the latter havesaved millions of lives a few of its relatives cause dissemi-nated infection in both humans and animals (Duong, 1996).

The organism responsible for mammalian disease iscalled Penicillium marneffei, a facultative intracellularpathogen and the only thermally dimorphic fungus of thegenus. The disease which it causes is called penicilliosismarneffei and is now the third most common opportunisticinfection in HIV-infected patients in certain parts of South-east Asia after extrapulmonary tuberculosis and Crypto-coccosis (Duong, 1996). The fungus was first described bySegretain in 1959 and namedPenicillium marneffei, inhonor of Dr Hubert Marneffe, the Director of the PasteurInstitute of Indochina (Segretain, 1959). Ironically, Segre-tain became the first known human case ofP. marneffeiinfection due to an accidental injury through a needle con-taminated with the fungus! In this issue Nittayananta pro-vides us with a comprehensive review of this relatively newillness uncommon in the pre-AIDS era. The disease arousesconcern, according to Nittayananta, not only due to itsincreasing prevalence but also due to the orofacial manifes-tations, which are rather nondescript, mimicking other fun-gal infections.

Human infections withP. marneffeihave occurred inpersons living and travelling throughout Southeast Asia andsporadic cases have been reported in other parts of theworld. The organism rarely causes infection in the immuno-logically competent, and disseminated infection is muchmore frequent in immunosuppressed patients, especiallythose with HIV infection. Hence the prevalence of the dis-ease is dependent not only on the extent of environmentalcontamination with infectious organisms and the frequencyof human exposure to the reservoir, but also on the preva-lence of HIV infection in the population.

Asymptomatic infections occur in healthy individuals

(possibly by inhalation of spores) with or without cervicallymphadenitis resembling tuberculosis. The most commonpresenting symptoms and signs are fever, anemia, weightloss and skin lesions. The latter are characterized by gen-eralized papules with central umbilication which sometimesprogress to necrosis. Some patients may have skin lesionsthat resemble acne vulgaris or seborrhea. Osteolytic bonelesions may be a feature of disseminated disease. Oralmanifestations of the disease include erosions or shallowulcers covered with slough both on the keratinised and non-keratinised mucosa.

The organism has been isolated most commonly fromskin, blood and bone marrow. Immunological diagnosisincludes detection with exoantigen and immunohistochem-ical methods. The primary differential diagnosis for sys-temic P. marneffeiinfections includes other disseminatedfungal infections, especiallyHistoplasma capsulatumandCryptococcus neoformans; tuberculosis should also beexcluded. Treatment of disseminated infection with par-enteral amphotericin B and itraconazole is efficacious(Supparatpinyoet al, 1994).

AlthoughP. marneffeiis endemic only in parts of South-east Asia, due to the explosive growth of tourism and travelit may present in any part of the world both in the healthyas well as the compromised. Hence, clinicians and scientistsworldwide must be aware of this emerging disease and itsprotean clinical features.

LP Samaranayake

References

Duong TA (1996). Infection due toPenicillium marneffei, anemerging pathogen: Review of 155 reported cases.Clin InfectDis 23: 125–130.

Segretain G (1959). Description d’une nouvelle espece de penicil-lium: Penicillium marneffei n.sp. Bull Societe MycologiqueFrance75: 412–416.

Supparatpinyo K, Khamwan CX, Baosoung Vet al (1994). Dis-seminatedPenicillium marneffeiinfection in Southeast Asia.Lancet344: 110–113.