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Diagnosis and management of Pneumocystis jirovecii infection
P Lewis White1, Matthijs Backx1, Rosemary A Barnes1,2
1a Public Health Wales Microbiology Cardiff, UHW , Cardiff , UK.
Introduction:
Pneumocystis jirovecii is a ubiquitous fungus, which causes pneumonia in humans. Diagnosis was hampered by the inability to culture the organism, and based on microscopic examination of respiratory samples or clinical presentation. New assays can assist in the diagnosis and even aid with the emergence of resistant infections. Areas covered: This manuscript will provide background information on Pneumocystis pneumonia (PcP). Diagnosis, from radiological to non-microbiological (e.g. Lactate dehydrogenase) and microbiological investigations (Microscopy, PCR, β-D-Glucan) will be discussed. Recommendations on prophylactic and therapeutic management will be covered. Expert commentary: PcP diagnosis using microscopy is far from optimal and false negatives will occur. With an incidence of 1% or less, the pre-test probability of not having PcP is 99% and testing is suited to excluding disease. Microscopy provides a high degree of diagnostic confidence but it is not infallible, and its lower sensitivity limits its application. Newer diagnostics (PCR, β-D-Glucan) can aid management and improve performance when testing less invasive specimens, such as upper respiratory samples or blood, alleviating clinical pressure. Combination testing may allow PcP to be both diagnosed and excluded, and molecular testing can assist in the detection of emerging resistant PcP.
Insights
Diagnosing Pneumocystis pneumonia (PcP) is challenging, but newer molecular assays like PCR and β-D-Glucan offer improved accuracy over traditional microscopy. These advanced diagnostics aid in detecting PcP and identifying drug-resistant infections.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Pulmonology
Background:
- Pneumocystis jirovecii is a common fungus causing pneumonia, particularly in immunocompromised individuals.
- Traditional diagnosis relies on microscopy and clinical symptoms, often limited by low sensitivity and inability to culture the organism.
- Emerging drug resistance necessitates improved diagnostic methods.
Purpose of the Study:
- To provide a comprehensive overview of Pneumocystis pneumonia (PcP).
- To discuss various diagnostic approaches, including traditional and novel methods.
- To cover management strategies and the role of new diagnostics in addressing resistance.
Main Methods:
- Review of radiological, non-microbiological, and microbiological diagnostic investigations for PcP.
- Discussion of microscopy, Polymerase Chain Reaction (PCR), and β-D-Glucan assays.
- Examination of prophylactic and therapeutic management recommendations.
Main Results:
- Microscopy for PcP diagnosis is suboptimal, frequently yielding false negatives.
- Newer diagnostics like PCR and β-D-Glucan demonstrate higher sensitivity, especially with less invasive samples (e.g., blood).
- Combination testing and molecular methods can improve diagnostic confidence and detect resistance.
Conclusions:
- Novel diagnostic tools significantly enhance PcP detection and management compared to traditional microscopy.
- Advanced assays facilitate earlier diagnosis, potentially from less invasive samples, and aid in identifying drug resistance.
- Future strategies should integrate newer diagnostics for more accurate and timely PcP patient care.
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