05/04/2008- Microbial biofilms are behind a nasty side effect of osteoporosis drugs like Fosamax, new research says. These biofilms, a mix of bacteria and sticky extracellular material, are causing jaw tissue infections in patients taking bisphosphonate drugs like Fosamax, Actonel and Boniva, according to a study conducted at the USC School of Dentistry. Earlier this year, another group of researchers linked biofilms to eye infections that were caused by recalled Renu with MoistureLoc Contact Lens solution in 2006.

Osteoporosis drugs are known to carry a number of side effects, including Osteonecrosis of the Jaw (ONJ), also known as Dead Jaw Syndrome, a condition in which the bone tissue in the jaw fails to heal after minor trauma such as a tooth extraction, causing the bone to be exposed. The exposure can eventually lead to infection and fracture and may require long-term antibiotic therapy or surgery to remove the dying bone tissue. In 2005, the labels for Fosamax and similar drugs was updated to include warnings about ONJ.
The USC researchers said ONJ occurs  when bacteria-laden biofilms infect the jaw after the bone is exposed, typically because of a tooth extraction or injury. The team used powerful scanning electron microscopes to study patients’ jawbone samples. The images revealed biofilm bacteria sprawling over pitted tissue. The scientists are now trying to determine why bisphosphonate drugs seem to open the door for biofilm-associated infections of the jaw.

This is not the first time biofilms have been linked to serious side effects.  In 2006, Bausch & Lomb issued a worldwide recall of Renu with MoistureLoc Contact Lens Solution after it was linked to hundreds of cases of Fusarium Keratitis, a rare eye infection that has the potential to cause blindness.  Earlier this year, researchers with the Center for Medical Mycology found the strain of Fusarium responsible for the Renu with MoistureLoc outbreak had the ability to form biofilms.  Biofilms are clusters of microbes held together by a glue like matrix.   This structure made the Fusarium extremely resistant to contact lens solutions and the body’s own immune system.

Not all cells can form biofilms, and unfortunately for Renu victims, contact lens solutions are not required to be tested against microbes with this ability.  In fact, Renu with MoistureLoc and other contact lens solutions are tested against a rare type of fungus obtained from a patient in Nigeria in 1970s.