Profiling bacterial community in upper respiratory tracts.
BACKGROUND
Infection by pathogenic viruses results in rapid epithelial damage and significantly impacts on the condition of the upper respiratory tract, thus the effects of viral infection may induce changes in microbiota. Thus, we aimed to define the healthy microbiota and the viral pathogen-affected microbiota in the upper respiratory tract. In addition, any association between the type of viral agent and the resultant microbiota profile was assessed.


METHODS
We analyzed the upper respiratory tract bacterial content of 57 healthy asymptomatic people (17 health-care workers and 40 community people) and 59 patients acutely infected with influenza, parainfluenza, rhino, respiratory syncytial, corona, adeno, or metapneumo viruses using culture-independent pyrosequencing.


RESULTS
The healthy subjects harbored primarily Streptococcus, whereas the patients showed an enrichment of Haemophilus or Moraxella. Quantifying the similarities between bacterial populations by using Fast UniFrac analysis indicated that bacterial profiles were apparently divisible into 6 oropharyngeal types in the tested subjects. The oropharyngeal types were not associated with the type of viruses, but were rather linked to the age of the subjects. Moraxella nonliquefaciens exhibited unprecedentedly high abundance in young subjects aged <6 years. The genome of M. nonliquefaciens was found to encode various proteins that may play roles in pathogenesis.


CONCLUSIONS
This study identified 6 oropharyngeal microbiome types. No virus-specific bacterial profile was discovered, but comparative analysis of healthy adults and patients identified a bacterium specific to young patients, M. nonliquefaciens.
School of Biosystem and Biomedial Science, Korea University, Seoul, Republic of Korea. hanayi@korea.ac.kr.|Department of Public Health Science, Graduate School, Korea University, Seoul, Republic of Korea. hanayi@korea.ac.kr.|Korea University Guro Hospital, Korea University, Seoul, Republic of Korea. hanayi@korea.ac.kr.
Hana
H
Yi
Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea. deyong@yuhs.ac.
Dongeun
D
Yong
Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea. leekcp@yuhs.ac.
Kyungwon
K
Lee
ChunLab, Inc., Seoul, Republic of Korea. yongjoon@chunlab.com.
Yong-Joon
YJ
Cho
ChunLab, Inc., Seoul, Republic of Korea. jchun@snu.ac.kr.|School of Biological Sciences & Institute of Bioinformatics (BIOMAX), Seoul National University, Seoul, Republic of Korea. jchun@snu.ac.kr.
Jongsik
J
Chun
D000293:Adolescent; D000328:Adult; D000368:Aged; D058345:Asymptomatic Infections; D001419:Bacteria / Q000235:genetics* / Q000302:isolation & purification; D002353:Carrier State; D060085:Coinfection / Q000382:microbiology; D005260:Female; D006190:Haemophilus / Q000235:genetics / Q000302:isolation & purification; D006282:Health Personnel; D006801:Humans; D008297:Male; D064307:Microbiota / Q000235:genetics*; D008875:Middle Aged; D009016:Moraxella / Q000235:genetics / Q000302:isolation & purification; D012137:Respiratory System / Q000382:microbiology*; D012141:Respiratory Tract Infections / Q000382:microbiology* / Q000821:virology; D013291:Streptococcus / Q000235:genetics / Q000302:isolation & purification; D014777:Virus Diseases; D055815:Young Adult