title: The Importance of Obligate Anaerobes and the Streptococcus anginosus Group in Pulmonary Abscess: A Clone Library Analysis Using Bronchoalveolar Lavage Fluid.
abstract: BACKGROUND
  Appropriate antibiotic use reduces the mortality of patients with lung abscess; however, 40-60% of the bacterial etiologies in these patients have remained unknown with the culture methods. Obligate anaerobes and the Streptococcus anginosus group are common pathogens in lung abscess, but a precise evaluation of these bacteria by ordinary culture methods seems to be difficult due to upper respiratory tract contamination.
  
  
  OBJECTIVE
  The aim of this study was to assess the microbiota of lung abscess by bronchoalveolar lavage fluid (BALF) using the molecular method in comparison to culture methods.
  
  
  METHODS
  BALF samples obtained from the affected lesions and sputum samples of 59 patients with lung abscess were evaluated. The microbiota in BALF was analyzed according to the molecular method using the 16S ribosomal RNA gene.
  
  
  RESULTS
  Fifty-six of the 59 BALF samples were positive in polymerase chain reaction analysis. Fusobacterium spp. (23.7%) were most frequently detected, followed by the S. anginosus group (15.3%), as the predominant phylotypes. Obligate anaerobes were detected in 42.4% of the BALF specimens as the predominant phylotypes, whereas the detection rate of obligate anaerobes was 13.6% by culture methods using BALF. In addition, the detection rate among those patients in whom the phylotype of obligate anaerobes was detected in >5% of the lung microbiota according to the molecular method was 86.5% in the 'mixed-bacterial' infection group.
  
  
  CONCLUSIONS
  The findings by the molecular method suggest that obligate anaerobes play important roles in the pathogenesis of lung abscess and provide additional bacterial information regarding conventional culture methods.
authors.affiliation: Department of Respiratory Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukae
authors.forename: Shingo
authors.initials: S
authors.lastname: Noguchi
authors.forename: Keisuke
authors.initials: K
authors.lastname: Naito
authors.forename: Toshinori
authors.initials: T
authors.lastname: Kawanami
authors.forename: Kei
authors.initials: K
authors.lastname: Yamasaki
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Fukuda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Akata
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Fukuda
authors.forename: Takashi
authors.initials: T
authors.lastname: Kido
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ishimoto
authors.forename: Noriho
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Hatsumi
authors.initials: H
authors.lastname: Taniguchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Yatera
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001431:Bacteriological Techniques; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D005260:Female; D006801:Humans; D008169:Lung Abscess / Q000382:microbiology*; D008297:Male; D064307:Microbiota / Q000235:genetics*; D008875:Middle Aged; D011446:Prospective Studies; D012336:RNA, Ribosomal, 16S / Q000032:analysis*; D034366:Streptococcus anginosus / Q000302:isolation & purification*
chemical_list: D012336:RNA, Ribosomal, 16S