How does a viral infection affect the local bacterial composition of the respiratory tract in children

EMBARGOED UNTIL: Monday 5/20, 3 PM MDT

(Symposium Session 144)

Milena Pitashny
Baylor College of Medicine
Houston, TX, United States
Phone: 832-359-6795
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The current study explored the bacterial ecology of the respiratory tract of pediatric patients infected with the respiratory virus, RSV. Severe RSV infection was found to be associated with a highly diverse and rich community of "commensal" or "beneficial" bacteria. When co-infection with pathogenic bacteria was present, that diversity was compromised, at the expenses of certain classes of "beneficial bacteria" like Firmicutes and Bacteroidetes. 

The Texas Children's Microbiome Center at Baylor College of Medicine, Houston, TX, is under the direction of James Versalovic, MD PhD, who has been actively involved in the Human Microbiome Project. The TCMC is interested in exploring the lower respiratory tract in children in order to define its Microbiome (composition of microbial communities) and the possible associations with disease states. Milena Pitashny, a MD clinical microbiologist, has been particularly interested in the Microbiome of pediatric patients affected by RSV. Presentation at ASM 2013, Denver, CO, May 20th 2013.

RSV is a viral infection that affects the respiratory tract of healthy children. When severe, it is a major cause of hospital admission and mortality, predominantly in developing countries. No specific treatment or vaccine, have effectively halted the occurrence and severity of RSV infection.

With just a few microliters of sample, a whole map of the microbial composition of a body site, can be determined at the DNA level with the next generation sequencing technology. In this pilot study, the bacterial composition of the lungs of RSV infected children was compared to non RSV controls and to patients with RSV co-infected with bacterial pathogens. It is to note that there was a great correlation between the reports of the clinical laboratory and the sequencing results when a bacterial pathogen was detected. However, the presence of dozens of distinct types of bacteria, were identified by sequencing while not detected by culture. This suggests that like other body parts, there is an unknown convention of microorganisms that coexist with humans and are not being detected by classical methods, and unlike what used to be thought and in accordance with other researchers, the lungs are far from being sterile. A clear pattern in the distribution of bacteria was seen in the group of patients infected with RSV, and the composition was highly diverse. This indicates that microbes rearrange in the presence of RSV. Further studies will determine the mechanisms by which these local microorganisms interact with viral and bacterial pathogens, with the host physical barriers and with the immune system.