Publication: Streptococcus pneumoniae Colonization Disrupts the Microbial Community within the Upper Respiratory Tract of Aging Mice

Colonization of Streptococcus pneumoniae within the upper respiratory tract (URT) of elderly individuals is a major concern, as it often results in the development of pneumonia, which can be deadly in this population. A study published by MIRC Masters’ student Netusha Thevaranjan, under the supervision of Dr. Dawn Bowdish, examined howNetusha-sm aging can change the composition of the respiratory microbial community and consequently, impact bacterial colonization. Using a mouse model of pneumococcal colonization, the study characterized the composition of the URT microbiota in young, middle-aged, and old mice in both the naïve state, and throughout the course of nasopharyngeal colonization with S. pneumoniae. It was shown that the composition of the URT microbiota differs with age, and that colonization with S. pneumoniae in older mice disrupted pre-existing microbial communities.

Furthermore, the study demonstrated that there were several interspecies interactions between S. pneumoniae and resident microbes. In particular,Streptococcus interacted competitively with Staphylococcus and synergistically with Haemophilus. This work provides insight into how aging influences bacterial colonization, and understanding the relationship between these two factors can help create strategies to protect the elderly from age-associated infections and disease. Read More

Puchta et al. Characterization of inflammatory responses during intranasal colonization with Streptococcus pneumoniae. Vis Exp. 2014 Jan 17;(83):e50490. doi: 10.3791/50490.

Puchta A, Verschoor CP, Thurn T, Bowdish DMCharacterization of inflammatory responses during intranasal colonization with Streptococcus pneumoniae. J Vis Exp. 2014 Jan 17;(83):e50490. doi: 10.3791/50490.

“Myeloid-Derived Suppressor Cells, Age & Cancer” 2013. Oncoimmunology.

Dr. Bowdish discusses the implication of our Verschoor et al publication “Blood CD33(+)HLA-DR(-) myeloid-derived suppressor cells are increased with age and a history of cancer.” in studies of aging and cancer in the below commentary.

Click image for .pdf.

MDSC commentary


This is an open access publication so please feel free to use the following image in presentations/publications providing that it is properly referenced.

MDSC commen figure

“Immunosenescence & novel vaccination strategies for the elderly” 2013. Dorrington et al. Frontiers in Immunology

What is the best way to reduce infectious disease in the elderly? Vaccination! Unfortunately the aging immune system presents a number of challenges for vaccine development. Bowdish lab PhD candidate Mike Dorrington discusses them in this review and presents a case for developing novel vaccines that work within the constraints of the aging immune system.

Media coverage: This paper was picked up by MDLinx. See their coverage here.

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Dorrington Fronteirs review

“Blood CD33+HLA-DR- myeloid-derived suppressor cells are increased with age and a history of cancer” 2013. Verschoor et al. JLB

MDSCs (myeloid derived suppressor cells) are a recently discovered and very heterogenous cell type that appear to directly suppress T cell responses and their presence in the tumour or the circulation is an extremely poor prognostic marker.

The Bowdish lab recently dipped our foot into the confusing world of MDSCs because we were curious to know whether their frequency increases with age and if so, could this explain why age is a risk factor for many cancers. They do increase with age and this may explain why some adaptive immune responses decline with age. One thing we were very surprised to find is that individuals who had any history of cancer but were believed to be in remission had higher levels of these cells in circulation. This begs the question – did these people have higher levels and to begin with and is this why they were predisposed to cancer? Or do they still have subclinical tumours that promote the development of MDSCs? Or does the suppressive environment of the cancer microenvironment stay with you for life? More studies (not by us, that was enough) are warranted.

For the .pdf click here

For the supplementary data, click here.