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Published on: February 23, 2014
Pneumocystis pneumonia
F J L Robberts1, L J Chalkley, L D Liebowitz
1Department of Medical Microbiology, Tygerberg Hospital, University of Stellenbosch, PO Box 19063, Tygerberg, 7505. lourensr@sun.ac.za
Abstract:
Pneumocystis jiroveci is a common cause of pneumonia in South African patients with AIDS. Sulphonamide resistance may become a problem in South Africa, as patients are treated with prophylactic co-trimoxazole when their CD4 counts fall below 200 cells/microliter. Failure of prophylaxis and treatment has been observed, possibly due to infection with sulphonamide-resistant strains. Sulphonamide resistance has been reported elsewhere, and is due to point mutations at codons 55 and 57 of the dihydropteroate synthase gene. Strain typing is useful for molecular epidemiological purposes.
Insights
Pneumocystis jiroveci pneumonia is a concern for South African AIDS patients. Sulphonamide resistance, linked to gene mutations, may cause treatment failures.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Molecular Epidemiology
Background:
- Pneumocystis jiroveci pneumonia (PCP) is a significant opportunistic infection in individuals with Acquired Immunodeficiency Syndrome (AIDS).
- Prophylactic co-trimoxazole is commonly administered to South African AIDS patients with CD4 counts below 200 cells/microliter.
- Observed treatment and prophylaxis failures suggest the potential emergence of sulphonamide-resistant Pneumocystis jiroveci strains.
Purpose of the Study:
- To highlight the potential clinical challenge of sulphonamide resistance in Pneumocystis jiroveci in South Africa.
- To discuss the molecular basis of sulphonamide resistance in Pneumocystis jiroveci.
- To underscore the utility of strain typing for molecular epidemiology.
Main Methods:
- Review of existing literature on Pneumocystis jiroveci pneumonia and sulphonamide resistance.
- Discussion of the genetic mutations associated with sulphonamide resistance (dihydropteroate synthase gene codons 55 and 57).
- Consideration of the role of molecular epidemiological tools like strain typing.
Main Results:
- Sulphonamide resistance in Pneumocystis jiroveci is a documented phenomenon globally.
- Specific point mutations in the dihydropteroate synthase gene are identified as the cause of resistance.
- The prophylactic use of co-trimoxazole in immunocompromised patients may exert selective pressure for resistant strains.
Conclusions:
- Sulphonamide-resistant Pneumocystis jiroveci poses a potential threat to effective PCP management in South Africa.
- Understanding the genetic basis of resistance is crucial for diagnostics and treatment strategies.
- Molecular strain typing is a valuable method for tracking the epidemiology of resistant strains.
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