Over-prescription of antibiotics, interbreeding of strains in the fertile environment of hospitals and use of the drugs in the production of livestock are all leading to resistant strains of bacteria, and the pipeline for new antibiotics has nearly run dry, The San Francisco Chronicle reported Sunday.

Only five new antibiotics have been approved in the last five years, compared to the early 1980's when 16 new treatments were in development, the newspaper said. The drop-off is mainly because drug companies are dropping out of the market, in favor of more lucrative drugs that must be taken for years or decades.

The lack of effective drugs is taking a toll, the Chronicle reported. About 99,000 Americans die each year from bacterial infections acquired in hospitals, and powerful strains like MRSA have made their way out of institutions and into the public at large -- most recently seen in a spate of outbreaks at schools.

To fix the problem, some experts -- like Dr. Louis Rice at Case Western Reserve University in Cleveland -- have proposed taxing drug companies that do not work on antibiotics to support research at companies that do.