Utility of Veillonella parvula polymerase chain reaction in diagnosing aspiration pneumonia: a prospective observational study.

Background: Aspiration pneumonia is a critical concern, particularly in older adults with comorbidities. Micro-aspiration is often underdiagnosed due to the lack of precise diagnostic tools. This study evaluated the utility of anaerobic PCR for Veillonella parvula compared with traditional diagnostic methods for predicting aspiration pneumonia.

Methods: This prospective observational case-control study included patients with new-onset acute respiratory failure requiring mechanical ventilation in intensive care units (ICUs) at a Taiwan medical centre (2022-2024). Demographic data, laboratory results and tracheal aspirates were collected within 48 h of ICU admission. PCR results for Veillonella spp. and V. parvula, along with pepsin and α-amylase levels, were analysed. Pneumonia diagnosis was confirmed by two pulmonologists.

Results: Among 87 patients (53 with aspiration pneumonia, 34 without), aspiration pneumonia primarily affected the right side and had atypical phenotypes. Demographics, traditional risk factors, comorbidities and disease severity were similar between groups. Veillonella spp. PCR showed higher sensitivity (92.5%) and specificity (97.1%) than V. parvula PCR (79.2% and 97.1%), chest radiographs with symptoms (73.6% and 88.2%), α-amylase (28.3% and 64.7%) and pepsin (73.6% and 38.2%). Logistic regression revealed that Veillonella spp. PCR had an adjusted odds ratio of 467.2 (95% CI 30.96-7049.4, p<0.001) for predicting aspiration pneumonia. Patients with aspiration pneumonia had longer ICU stays (18.28 days versus 13.03 days, p=0.001) and ventilator days (17.30 days versus 12.09 days, p=0.002).

Conclusions: Veillonella spp. PCR offers better diagnostic sensitivity and specificity than traditional methods for aspiration pneumonia, potentially guiding antibiotic stewardship.