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Role of Pneumocystis jirovecii in patients with different pulmonary underlying condition using a nested-PCR
L Martínez Lamas1, M T Pérez Rodríguez, I Álvarez Ramos
1Lucía Martínez Lamas, Hospital Meixoeiro. EOXI Vigo, C/Camiño do Miexoeiro s/n, CP: 36200 Vigo. Pontevedra. Galicia. Spain. lucia.martinez.lamas@sergas.es.
Objective:
The prevalence of Pneumocystis jirovecii colonization and its role in pulmonary disease remains unclear. PCR methods have shown an improved sensitivity in the detection of this fungus. It has been suggested that the PCR results be combined with another test such as IFA to create a diagnostic algorithm.
Methods:
A multiplex nested-PCR procedure with a 16S rRNA gene as the internal amplification control was evaluated to determine the role of P. jirovecii in pulmonary disease.
Results:
A 20% of the 199 bronchoalveolar lavage samples were PCR-positive, 13.5% samples were PCR-inhibited, and the rate of Pneumocystis-colonisation was 6.4%. The sensitivity, specificity, positive predictive value and negative predictive value of the nested-PCR were 100%, 93%, 70% and 100%, respectively. The sensitivity of the nested-PCR was higher than the current "gold standard" immunofluorescence assay (IFA) (p< 0.0001). PCR-negative and PCR-positive patients did not show any clinical or radiological differences in the medical variables studied.
Conclusions:
PCR could help the diagnosis of Pneumocystis pulmonary disease given the high negative predictive value of the technique. P. jirovecii DNA can frequently be detected in healthy population, so the analysis of the patient medical history is critical to make the correct clinical decision.
Insights
Polymerase chain reaction (PCR) effectively detects Pneumocystis jirovecii in lung disease, offering high accuracy. However, P. jirovecii DNA is common in healthy individuals, necessitating clinical history for diagnosis.
Area of Science:
- Medical Mycology
- Infectious Diseases
- Diagnostic Microbiology
Background:
- The prevalence of Pneumocystis jirovecii colonization and its role in pulmonary disease are not well understood.
- Polymerase chain reaction (PCR) offers enhanced sensitivity for detecting Pneumocystis jirovecii.
- Combining PCR with other tests like immunofluorescence assay (IFA) may improve diagnostic accuracy.
Purpose of the Study:
- To evaluate a multiplex nested-PCR procedure for detecting P. jirovecii in pulmonary disease.
- To determine the diagnostic performance of nested-PCR compared to IFA.
Main Methods:
- A multiplex nested-PCR assay using a 16S rRNA gene as an internal control was employed.
- Bronchoalveolar lavage samples from 199 patients were analyzed.
Main Results:
- 20% of samples were PCR-positive, with a 6.4% Pneumocystis colonization rate.
- Nested-PCR demonstrated 100% sensitivity, 93% specificity, 70% positive predictive value, and 100% negative predictive value.
- Nested-PCR sensitivity significantly exceeded IFA (p<0.0001).
Conclusions:
- PCR is valuable for diagnosing Pneumocystis pulmonary disease due to its high negative predictive value.
- The frequent detection of P. jirovecii DNA in healthy individuals underscores the importance of clinical history for accurate diagnosis.
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