Bacteria in the nose of young adults during wellness and rhinovirus colds: detection by culture and microarray methods in 100 nasal lavage specimens
Funding sources for the study: Pendleton Pediatric Infectious Disease Laboratory at the University of Virginia (bacterial cultures); The Helsinki Central Hospital Fund (EVO) and Mobidiag, Ltd. (extraction and microarray); NexBio unrestricted grant (experimental rhinovirus infection); National Institute of General Medical Sciences of the National Institutes of Health (T32GM008715 to E.K.A.).
Potential conflict of interest: S.L. is an employee of Mobidiag, Ltd. M.M. was employed by Mobidiag, Ltd., at the time of the microarray experiments. E.K.A., A.P., J.O.H., M.M.S., and B.W. have no conflicts of interest.
Patients with viral respiratory infections/viral rhinitis/common colds are often treated with antibiotic; however, there is little information on whether or how bacterial microbiota in the nose and nasopharynx might influence the course of viral illnesses.
To initiate investigation of possible interaction between viral respiratory illness and microbiota of the nose/nasopharynx, we used microarray technology to examine 100 nasal lavage fluid (NLF) samples for bacterial species and recorded the bacterial titer of culturable bacteria. Rhinovirus illnesses were induced by self-inoculation using the “finger to nose or eye natural transmission route” in 10 otherwise healthy young adults. NLF samples were collected during wellness and at specific time points following experimental rhinovirus inoculation.
The rhinovirus infection rate was 70%. There were no consistent changes in the prevalence of different bacterial species determined by microarray and bacterial titer by culture methods during rhinovirus infection. The bacterial profile in NLF samples showed high variability between volunteers but low variability in multiple NLFs obtained before and following infection from the same volunteer. Streptococcus epidermidis/coagulase-negative staphylococcus (CNS) were identified in all 10 subjects. One or more bacterial sinus/otitis pathogens were identified by microarray in 6 of the 10 volunteers. The microarray identified a few bacteria not included in traditional bacterial cultures.
Our pilot study showed that each of the 10 volunteers had a unique bacterial profile in the nose by microarray analysis and that bacterial load did not change during experimental rhinovirus colds. Larger scale studies are warranted.