Determining the Possible Etiology of Hospital-Acquired Pneumonia Using a Clone Library Analysis in Japan

Abstract

Obtaining precise etiological information regarding causative bacteria is important for the proper use of antimicrobials in hospital-acquired pneumonia (HAP), which is associated with a high rate of mortality. The aim of this study was to comparatively investigate the bacterial diversity in bronchoalveolar lavage fluid (BALF) in Japanese patients with HAP by the clone library method using the 16S rRNA gene. This study included Japanese patients with HAP who were treated at our hospital and referring hospitals. BALF specimens were obtained from pneumonia lesions identified on chest radiographs and/or computed tomography. Sputum specimens were also evaluated in patients with sputum production. Sixty-eight patients were ultimately enrolled. BALF cultivation revealed bacterial positivity in 53 of 68 (77.9%) patients, and Staphylococcus aureus (30.9%) was the most frequently isolated, followed by Pseudomonas aeruginosa (16.2%), and Escherichia coli (10.3%). In contrast, the clone library analysis identified the presence of some bacterial phenotype in 65 of 68 (95.6%) patients, and streptococci (16.2%), Corynebacterium species (11.8%), anaerobes (10.3%) were frequently detected as the predominant phylotypes. Both methods tended to detect S. aureus, Klebsiella pneumoniae, and E. coli in patients with late-onset pneumonia. In addition, the cases that phylotypes of S. aureus and P. aeruginosa were found to account for > 5% of the bacterial flora of each case were 42.9% and 72.7%, respectively. These results indicate that attention should be paid to the roles of gram-positive bacilli such as streptococci, Corynebacterium species and anaerobes, in addition to Gram-negative bacilli, in the pathogenesis of HAP.

Respiratory microbiome profiles differ by recent hospitalization and nursing home residence in patients on mechanical ventilation

“…are among the commensal flora of the nasopharynx [32], a causative role in pneumonia was recently described [33][34][35][36]. The identification of Corynebacteria subspecies is now possible using new diagnostic technologies, such as matrix-assisted laser desorption ionization time of flight mass spectrometry and 16S rRNA gene sequencing [13,[33][34][35]37]. Based on such studies, Clariot et al suggested that Corynebacterium spp.…”

Respiratory Microbiome Profiles Differ by Recent Hospitalization and Nursing Home Residence in Patients on Mechanical Ventilation

“…are among the commensal ora of the nasopharynx [32], a causative role in pneumonia was recently described [33][34][35][36]. The identi cation of Corynebacteria subspecies is now possible using new diagnostic technologies, such as matrix-assisted laser desorption ionization time of ight mass spectrometry and 16S rRNA gene sequencing [13,[33][34][35]37]. Based on such studies, Clariot et al suggested that Corynebacterium spp.…”

Clinical characteristics of patients with bacterial pleuritis in the presence of Streptococcus anginosus group and obligate anaerobes detected by clone library analysis

“…Our previous reports investigating pneumonia showed that there was a higher ratio of patients with mixed infections of healthcare‐associated pneumonia (HCAP) and hospital‐acquired pneumonia (HAP) compared to patients with community‐acquired pneumonia (CAP). In addition, streptococci were highly detected in elderly pneumonia patients and pneumonia patients with poor general health conditions . In patients with bacterial pleuritis, culture‐based mixed infection was reported in 9.8%–24.0% of patients, with insufficient data detailing the combination of bacterial species.…”

“…In addition, streptococci were highly detected in elderly pneumonia patients and pneumonia patients with poor general health conditions. [14][15][16]26 In patients with bacterial pleuritis, culture-based mixed infection was reported in 9.8%-24.0% 25,27,28 of patients, with insufficient data detailing the combination of bacterial species. In this study, 10 patients were categorized in the 'mixed bacterial-dominant' group and 9 of 10 (90%) patients in the 'mixed bacterial dominant' group were also sorted into the obligate anaerobic group.…”

“…[7][8][9][10] Recently, culture-independent molecular analysis methods for detecting microorganisms have been developed for respiratory infections. 11,12 Furthermore, we previously reported on the composition of the microbiota in patients of bacterial pleuritis 13 and several types of pneumonia [14][15][16] using clone library analysis targeting the 16S ribosomal RNA (rRNA) gene. In our previous report of bacterial pleuritis using clone library analysis, higher rates (43.8%) of anaerobic phylotypes were detected.…”