Two antibiotics may be better than one

CHICAGO, Jan. 27 (UPI) -- Two antibiotics prescribed together might be more effective in fighting pathogenic bacteria than either drug on its own, U.S. researchers said.

Researchers at the University of Illinois at Chicago and the Weizman Institute of Science in Israel said the antibiotics lankacidin and lankamycin -- produced naturally by the microbe streptomyces -- are marginally effective in warding off pathogens.

Lead investigator Alexander Mankin, professor and associate director of the Illinois school's Center for Pharmaceutical Biotechnology, found that when used together, the two antibiotics are much more successful in inhibiting growth of dangerous pathogens such as methicillin-resistant Staphylococcus aureus, and possibly others.

Lankacidin and lankamycin act upon the ribosomes -- the protein-synthesizing factories of the cell. Some antibiotics stave off an infection by preventing the ribosome from assembling proteins, while others bind and block the protein's passage, the researchers say.

Biochemical analysis and molecular modeling showed that lankamycin binds in the ribosomal tunnel right next to lankacidin.

"What we found most amazing is that the two antibiotics appeared to help each other in stopping pathogens from making new proteins and in inhibiting bacterial growth," Mankin said in a statement.

The research is published in the online edition of the Proceedings of the National Academy of Sciences.