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Updated: Jun 12, 2026
Microbiological Rapid On-Site Evaluation for Pulmonary Infectious Diseases
Published on: March 1, 2024
Oral Wash PCR Improves the Diagnosis of Pneumocystis Pneumonia in Immunocompromised Patients Without HIV: A
Florence Robert-Gangneux1, Gilles Nevez2, Céline Damiani3
1Univ Rennes, Inserm, EHESP, Irset, UMR S 1085, CHU Rennes, 35000 Rennes, France.
Background:
Pneumocystis pneumonia (PCP) is increasingly common in HIV-negative immunocompromised patients, who generally have low fungal burdens. Bronchoalveolar lavage (BAL) may be poorly tolerated in fragile patients, and oropharyngeal wash (OW) could be an interesting alternative, but its effectiveness remains underexplored in these patients.
Methods:
A prospective multicenter cohort study was conducted to assess PCR on OW in HIV-negative patients undergoing BAL to document respiratory symptoms. Beta-1-3-D-glucan (BDG) was also measured on blood samples. Patients were classified by a multidisciplinary committee as having definite PCP, colonization, possible PCP or without Pneumocystis. Positive predictive value (PPV), negative predictive value (NPV) and ROC analysis were determined for each test. Agreement between BAL PCR, OW PCR and BDG was assessed.
Results:
Statistical analyses were performed on 369 patients: 76 with PCP, 55 colonized, 214 without Pneumocystis, and 24 possible PCP. PCR in OW was positive in 81.6%, 30.9%, 0%, and 45.8% of patients with PCP, colonization, no PCP, and possible PCP, respectively. Mean fungal loads in OW were 4251±15501 and 3±8.5 copies/mL in PCP and colonized patients, respectively (p<0.0001). PPV and NPV of OW PCR were 78.5% and 73.1%, respectively. ROC analysis identified a threshold of 7 copies/mL for OW to achieve a PPV of 90%, with a sensitivity of 73.5%. Agreement between OW PCR and BDG was poor (κ<0.4), but the combination of BDG+/OW PCR+ yielded a PPV of 92%.
Conclusions:
PCR on OW is a useful non-invasive tool for diagnosing PCP in HIV-negative patients.
Insights
Oropharyngeal wash PCR is a valuable, non-invasive method for diagnosing Pneumocystis pneumonia (PCP) in immunocompromised, HIV-negative patients. This test offers an alternative to bronchoalveolar lavage, improving diagnostic accessibility.
Area of Science:
- Infectious Diseases
- Mycology
- Diagnostic Microbiology
Background:
- Pneumocystis pneumonia (PCP) is an opportunistic infection affecting immunocompromised individuals, including HIV-negative patients.
- Traditional diagnostic methods like bronchoalveolar lavage (BAL) can be invasive and poorly tolerated by fragile patients.
- Oropharyngeal wash (OW) presents a less invasive alternative, but its diagnostic utility for PCP in this population requires further investigation.
Purpose of the Study:
- To evaluate the effectiveness of Polymerase Chain Reaction (PCR) on oropharyngeal wash (OW) for diagnosing Pneumocystis pneumonia (PCP) in HIV-negative immunocompromised patients.
- To compare the performance of OW PCR with blood-based Beta-1-3-D-glucan (BDG) testing and BAL PCR.
- To determine the diagnostic accuracy, including positive and negative predictive values, of OW PCR.
Main Methods:
- A prospective, multicenter cohort study involving 369 HIV-negative patients undergoing BAL for respiratory symptoms.
- Collection of oropharyngeal wash (OW) samples for PCR analysis and blood samples for Beta-1-3-D-glucan (BDG) testing.
- Classification of patients into definite PCP, colonization, possible PCP, or no Pneumocystis groups by a multidisciplinary committee, with subsequent ROC analysis and agreement assessments.
Main Results:
- OW PCR demonstrated high positivity rates in patients with PCP (81.6%) and colonization (30.9%), with significantly lower fungal loads in colonized individuals.
- The positive predictive value (PPV) and negative predictive value (NPV) for OW PCR were 78.5% and 73.1%, respectively.
- A threshold of 7 copies/mL for OW PCR achieved a 90% PPV with 73.5% sensitivity. Combining BDG and OW PCR yielded a PPV of 92%.
Conclusions:
- PCR analysis of oropharyngeal wash (OW) is a practical and non-invasive diagnostic tool for Pneumocystis pneumonia (PCP) in HIV-negative immunocompromised patients.
- OW PCR offers a valuable alternative to more invasive procedures like BAL, enhancing diagnostic accessibility.
- The combination of OW PCR and BDG testing further improves diagnostic confidence for PCP.
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