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Molecular evidence for strain dissemination of Penicillium marneffei: an emerging pathogen in Taiwan
P R Hsueh1, L J Teng, C C Hung
1Departments of Laboratory Medicine and Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
Abstract:
From January 1987 through December 1998, Penicillium marneffei infection (23 patients) or colonization (1 patient) was diagnosed in a total of 24 patients in Taiwan. Of these 24 patients, 16 (67%) had AIDS and 20 (83%) had disseminated P. marneffei infection. The majority (63%) of the infections were considered indigenous. The number of cases has increased markedly in recent years, with 17 of the 24 cases diagnosed from 1996 through 1998. Twenty preserved isolates of P. marneffei, recovered from 11 patients treated at National Taiwan University Hospital during the period of January 1996 through December 1998, were studied to determine the epidemiology of P. marneffei infections. Among the 20 isolates, a total of 8 strains (highly related isolates) were identified on the basis of tests for susceptibility to 5 antifungal agents, for chromosomal DNA restriction fragment-length polymorphism types, and for randomly amplified polymorphic DNA patterns. One of the strains (6 isolates) was isolated from 4 patients treated in 1997 and 1998. Strain spreading of P. marneffei may partially contribute to the increased number of infections caused by this organism in immunosuppressed patients in Taiwan.
Insights
Penicillium marneffei infections are increasing in Taiwan, particularly among AIDS patients. Genetic analysis of P. marneffei strains suggests that strain spreading may contribute to this rise in infections.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Epidemiology
Background:
- Penicillium marneffei is an emerging fungal pathogen in Taiwan.
- Cases of P. marneffei infection have increased significantly, especially from 1996-1998.
- Most infections occur in patients with Acquired Immunodeficiency Syndrome (AIDS) and are disseminated.
Purpose of the Study:
- To investigate the epidemiology of P. marneffei infections in Taiwan.
- To analyze the genetic relatedness of P. marneffei isolates from patients.
- To explore potential factors contributing to the increasing incidence of P. marneffei infections.
Main Methods:
- Retrospective analysis of P. marneffei cases diagnosed between 1987 and 1998 in Taiwan.
- Molecular typing of 20 P. marneffei isolates using antifungal susceptibility testing, chromosomal DNA restriction fragment-length polymorphism (RFLP), and randomly amplified polymorphic DNA (RAPD) patterns.
- Identification of 8 distinct P. marneffei strains based on molecular and phenotypic characteristics.
Main Results:
- A total of 24 P. marneffei cases were identified, with a marked increase in recent years (17 cases from 1996-1998).
- The majority of infections (83%) were disseminated, and 67% occurred in patients with AIDS.
- Molecular analysis revealed 8 highly related strains among the 20 isolates, with one strain isolated from 4 patients in 1997-1998.
Conclusions:
- The increasing incidence of P. marneffei infections in Taiwan, particularly in immunosuppressed individuals, is a significant public health concern.
- Evidence suggests that strain spreading of P. marneffei may be a contributing factor to the observed increase in infections.
- Further epidemiological and molecular studies are warranted to understand and control the spread of this opportunistic fungal pathogen.