Bacteria Involved in Ear Infections Resist Clearance by the Immune System
EMBARGOED UNTIL: Sunday 5/19, 3 PM MDT
(Symposium Session 71, Paper )
Wake Forest School of Medicine
Winston-Salem, NC, United States
Great strides are being made in determining how bacteria commonly found in the human nose are able to spread and cause disease in children. Haemophilus influenzae is a common bacterium that can cause both acute and chronic middle ear infections, a condition responsible for a large majority of childhood disease and of great importance worldwide. Pediatric ear infections have an estimated economic burden of $3.8 billion annually in the U.S. and remain one of the leading causes of hearing loss in children. Normally a harmless commensal bacterium, H. influenzae is able to avoid initial killing and clearance by the immune system and cause opportunistic disease when host defenses are down, as in the cases of viral infection or chronic allergies. One way this is accomplished appears to be a unique mechanism that subverts the human immune response in order to persist and cause disease.
Postdoctoral fellow Lauren King will present her project titled “The Interaction of Haemophilus influenzae and Host Phagocytes” on May 19, 2013 at the American Society for Microbiology General Meeting in Denver, Colorado. Dr. King works in the lab of Dr. Edward Swords at Wake Forest School of Medicine in Winston-Salem, North Carolina. The Swords lab is funded by grants from the National Institutes for Health and AstraZeneca.
By closely examining the interaction of host immune cells with H. influenzae, Dr. King has discovered that the bacteria are able to survive inside a subset of white blood cells called neutrophils that are normally responsible for eliminating infectious agents. They do this by disabling the neutrophil’s ability to kill bacteria and in fact killing the neutrophils. H. influenzae then builds a community on top of the dead neutrophils’ own DNA and proteins. The bacteria living in this community are much more resistant to immune clearance and treatment by antibiotics, making this a likely mechanism by which H. influenzae are able to persist and cause chronic middle ear infections. By determining how these normally innocuous bacteria are able to invade and cause disease, it will be possible to better prevent and treat middle ear infections.