title: Significance of anaerobes and oral bacteria in community-acquired pneumonia.
abstract: BACKGROUND
  Molecular biological modalities with better detection rates have been applied to identify the bacteria causing infectious diseases. Approximately 10-48% of bacterial pathogens causing community-acquired pneumonia are not identified using conventional cultivation methods. This study evaluated the bacteriological causes of community-acquired pneumonia using a cultivation-independent clone library analysis of the 16S ribosomal RNA gene of bronchoalveolar lavage specimens, and compared the results with those of conventional cultivation methods.
  
  
  METHODS
  Patients with community-acquired pneumonia were enrolled based on their clinical and radiological findings. Bronchoalveolar lavage specimens were collected from pulmonary pathological lesions using bronchoscopy and evaluated by both a culture-independent molecular method and conventional cultivation methods. For the culture-independent molecular method, approximately 600 base pairs of 16S ribosomal RNA genes were amplified using polymerase chain reaction with universal primers, followed by the construction of clone libraries. The nucleotide sequences of 96 clones randomly chosen for each specimen were determined, and bacterial homology was searched. Conventional cultivation methods, including anaerobic cultures, were also performed using the same specimens.
  
  
  RESULTS
  In addition to known common pathogens of community-acquired pneumonia [Streptococcus pneumoniae (18.8%), Haemophilus influenzae (18.8%), Mycoplasma pneumoniae (17.2%)], molecular analysis of specimens from 64 patients with community-acquired pneumonia showed relatively higher rates of anaerobes (15.6%) and oral bacteria (15.6%) than previous reports.
  
  
  CONCLUSIONS
  Our findings suggest that anaerobes and oral bacteria are more frequently detected in patients with community-acquired pneumonia than previously believed. It is possible that these bacteria may play more important roles in community-acquired pneumonia.
authors.affiliation: Department of Respiratory Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Yamasaki
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kawanami
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yatera
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Fukuda
authors.forename: Shingo
authors.initials: S
authors.lastname: Noguchi
authors.forename: Shuya
authors.initials: S
authors.lastname: Nagata
authors.forename: Chinatsu
authors.initials: C
authors.lastname: Nishida
authors.forename: Takashi
authors.initials: T
authors.lastname: Kido
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishimoto
authors.forename: Hatsumi
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001421:Bacteria, Anaerobic / Q000235:genetics*; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology; D017714:Community-Acquired Infections / Q000382:microbiology*; D005260:Female; D006192:Haemophilus Infections / Q000175:diagnosis / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques; D058889:Molecular Typing; D009055:Mouth / Q000382:microbiology*; D011019:Pneumonia, Mycoplasma / Q000175:diagnosis / Q000382:microbiology*; D011018:Pneumonia, Pneumococcal / Q000175:diagnosis / Q000382:microbiology*; D012329:RNA, Bacterial / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013183:Sputum / Q000382:microbiology; D055815:Young Adult
chemical_list: D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S