Alternating Antibiotics Can Help Beat Resistant Bacteria

The World Health Organisation identifies antibiotic resistance as one of the major global threats. With bacterial strains getting resistant to antibiotics, scientists are now posed with a challenge of developing a new range of potent drugs.Experts at the University of Exeter, Britain, have found a simple way of administering antibiotics that may help improve treatment of bacterial infection. It may also reduce the risk of the bacteria becoming resistant to antibiotics, thus maintaining the long-term effectiveness of the drugs, says a new study. The new technique called 'sequential treatments' uses alternating doses of antibiotics at low dosages."Our study finds a complex relationship between dose, bacterial population densities and drug resistance," said lead author Robert Beardmore from the University of Exeter in Britain.The research indicates that drug treatments with two antibiotics can be designed to kill bacteria at dosages that would ordinarily cause rapid development of drug resistance and sustained bacterial growth, when administered alone or in combination, the researchers noted."As we demonstrate, it is possible to reduce bacterial load to zero at dosages that are usually said to be sub-lethal," Beardmore pointed out.The researchers used a test tube model of a bacterial infection to show that even in bacteria that already harbour drug resistance genes, sequential treatments could deal with the bacteria even when much higher doses of single drugs or mixtures of two drugs failed to do so.The researchers also discovered that although sequential treatments did not suppress the rise of all drug resistant mutations in the bacteria, one drug would 'sensitise' the bacteria to the second drug, and therefore reduce the risk of resistance occurring.The findings appeared in the journal PLOS Biology.