Background Oral cavity is a reservoir of various respiratory pathogens, and poor oral hygiene is associated with an increase in anaerobic bacteria in oral cavity. In addition, it positively relates higher risk of developing pneumonia and increased pneumonia‐related mortality. However, the association between poor oral hygiene and increase in obligate anaerobes in the lungs of pneumonia patients is unclear. Methods A total of 39 patients with pneumonia in whom bronchoscopic examination and oral hygiene evaluation were performed were prospectively enrolled. The microbiota of the bronchoalveolar lavage fluid (BALF) directly obtained from the pneumonia lesion was analysed by the clone library analysis. In addition, oral hygiene evaluations were performed using oral hygiene index (OHI), tongue coating score, oral dryness, and community periodontal index of treatment needs (CPITN). The association between the detection of oral streptococci and obligate anaerobes and oral hygiene status was evaluated. Results Using the clone library analysis of BALF, the phylotypes of oral streptococci and obligate anaerobes were detected in 31 (79.5%) and 26 (66.7%) patients, respectively. Increased oral dryness, OHI, and CPITN, but not the tongue coating score, significantly correlated with higher rate of detection of obligate anaerobes, although no significant associations between the detection of oral streptococci in the lungs and each oral hygiene evaluation were observed. Significantly higher number of obligate anaerobes were detected in the lungs in patients with total oral hygiene score of ≥ 5 (P = 0.008). Conclusion Poor oral hygiene is associated with increased obligate anaerobes in the lungs of patients with pneumonia.

Next-generation sequencing (NGS) technologies have been applied in bacterial flora analysis. However, there is no standardized protocol, and the optimal clustering threshold for estimating bacterial species in respiratory infection specimens is unknown. This study was conducted to investigate the optimal threshold for clustering 16S ribosomal RNA gene sequences into operational taxonomic units (OTUs) by comparing the results of NGS technology with those of the Sanger method, which has a higher accuracy of sequence per single read than NGS technology. This study included 45 patients with pneumonia with aspiration risks and 35 patients with lung abscess. Compared to Sanger method, the concordance rates of NGS technology (clustered at 100%, 99%, and 97% homology) with the predominant phylotype were 78.8%, 71.3%, and 65.0%, respectively. With respect to the specimens dominated by the Streptococcus mitis group, containing several important causative agents of pneumonia, Bray Curtis dissimilarity revealed that the OTUs obtained at 100% clustering threshold (versus those obtained at 99% and 97% thresholds; medians of 0.35, 0.69, and 0.71, respectively) were more similar to those obtained by the Sanger method, with statistical significance (p < 0.05). Clustering with 100% sequence identity is necessary when analyzing the microbiota of respiratory infections using NGS technology.

No abstract

A 79-year-old Japanese man with polymyalgia rheumatica was admitted to hospital with coronavirus disease (COVID-19). On admission, he was treated with ciclesonide inhalation, ivermectin, and meropenem. He was intubated 6 days after admission, and methylprednisolone therapy was initiated (1000 mg/day). Hypoxemia and chest radiographic findings temporarily improved. However, chest computed tomography showed bilateral ground-glass attenuations, multiple nodules, and consolidation. Aspergillus fumigatus was cultured from the tracheal aspirate and he was diagnosed with COVID-19-associated invasive pulmonary aspergillosis (CAPA) and treated with liposomal amphotericin B. However, he died 28 days after admission.

No abstract