Published January 24, 2013
University at Buffalo researchers will use a $1.6 million grant from the National Institutes of Health to develop the first vaccine against an understudied bacterium that causes at least 10 percent of middle ear infections in children.
Already, the scientists are testing several promising antigens against Moraxella catarrhalis. A new vaccine could be ready for human testing in three to five years, they say.
The UB scientists, who received the grant from the NIH’s National Institute on Deafness and Other Communication Disorders, are among only a handful of researchers worldwide studying M. catarrhalis.
To combat the organism, they’re identifying similar antigens among all strains so a vaccine based on a single antigen will protect against as many strains of the bacterium as possible.
“Based on our results thus far, it looks like we will be able to identify antigens that are identical or very similar among all strains and genetic lineages,” says principal investigator Timothy F. Murphy, MD, SUNY Distinguished Professor of Medicine and Microbiology and Immunology.
The researchers are using bioinformatics to identify genes predicted to encode proteins on the organism’s surface, construct a gene chip to test which of the 300-plus possible genes on the surface are identical or similar, and then clone genes for some of the predicted proteins for testing in mouse models and in vivo.
Originally considered a harmless bacterium, M. catarrhalis causes milder cases of middle ear infections—or otitis media—than other bacteria.
However, these infections are becoming more prevalent, perhaps because existing vaccines against ear infections caused by other bacteria are changing colonization patterns among otitis media pathogens.
Of the 15 to 20 million annual cases of otitis media in the U.S., about 10 percent are recurring.
“When a child has the infection, the middle ear fills with fluid, a condition that can last for a month or longer,” explains Murphy, senior associate dean for clinical and translational research.
“During that time, the child’s hearing is muffled, which disrupts the normal development of language and speech skills, potentially resulting in long-term delays and learning problems in school.”
Recurrent ear infections also require repeated courses of antibiotics, which contribute to antibiotic resistance. Some children must undergo insertion of drainage tubes under general anesthesia.
A vaccine against M. catarrhalis may have implications beyond middle ear infections, the researchers note: They hope it also can be used to prevent infections in Chronic Obstructive Pulmonary Disorder (COPD).
For more than a decade, Murphy, who directs UB’s Clinical and Translational Science Institute, has studied how M. catarrhalis causes both type of infections.