title: The significance of oral streptococci in patients with pneumonia with risk factors for aspiration: the bacterial floral analysis of 16S ribosomal RNA gene using bronchoalveolar lavage fluid.
abstract: BACKGROUND
  Aspiration pneumonia has been a growing interest in an aging population. Anaerobes are important pathogens, however, the etiology of aspiration pneumonia is not fully understood. In addition, the relationship between the patient clinical characteristics and the causative pathogens in pneumonia patients with aspiration risk factors are unclear. To evaluate the relationship between the patient clinical characteristics with risk factors for aspiration and bacterial flora in bronchoalveolar lavage fluid (BALF) in pneumonia patients, the bacterial floral analysis of 16S ribosomal RNA gene was applied in addition to cultivation methods in BALF samples.
  
  
  METHODS
  From April 2010 to February 2014, BALF samples were obtained from the affected lesions of pneumonia via bronchoscopy, and were evaluated by the bacterial floral analysis of 16S rRNA gene in addition to cultivation methods in patients with community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP). Factors associated with aspiration risks in these patients were analyzed.
  
  
  RESULTS
  A total of 177 (CAP 83, HCAP 94) patients were enrolled. According to the results of the bacterial floral analysis, detection rate of oral streptococci as the most detected bacterial phylotypes in BALF was significantly higher in patients with aspiration risks (31.0 %) than in patients without aspiration risks (14.7 %) (P = 0.009). In addition, the percentages of oral streptococci in each BALF sample were significantly higher in patients with aspiration risks (26.6 ± 32.0 %) than in patients without aspiration risks (13.8 ± 25.3 %) (P = 0.002). A multiple linear regression analysis showed that an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of ≥3, the presence of comorbidities, and a history of pneumonia within a previous year were significantly associated with a detection of oral streptococci in BALF.
  
  
  CONCLUSIONS
  The bacterial floral analysis of 16S rRNA gene revealed that oral streptococci were mostly detected as the most detected bacterial phylotypes in BALF samples in CAP and HCAP patients with aspiration risks, especially in those with a poor ECOG-PS or a history of pneumonia.
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Akata
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yatera
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Yamasaki
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kawanami
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Naito
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Noguchi
authors.affiliation: Department of Microbiology, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.|Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishimoto
authors.affiliation: Department of Microbiology, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan.
authors.forename: Hatsumi
authors.initials: H
authors.lastname: Taniguchi
authors.affiliation: Department of Respiratory Medicine, School of Medicine, University of Occupational and Environmental Health, Japan, 1-1 Iseigaoka, Yahatanishiku, Kitakyushu city, Fukuoka, 807-8555, Japan. hmukae@med.uoeh-u.ac.jp.|Second Department of Internal Medicine, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan. hmukae@med.uoeh-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D017714:Community-Acquired Infections / Q000382:microbiology*; D003428:Cross Infection / Q000382:microbiology*; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011015:Pneumonia, Aspiration / Q000382:microbiology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012044:Regression Analysis; D012307:Risk Factors; D013291:Streptococcus / Q000145:classification*
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Anaerobes; Aspiration pneumonia; Aspiration risks; Bacterial floral analysis; 16S ribosomal RNA gene; Oral streptococci