Rise of ampicillin resistance began years before human use.

The rise of ampicillin resistance began years before human use,and likely triggered by overuse of penicillin s in agriculture in the 1950s. Bacteria that can pass on genes resistant to ampicillin, one of the most commonly used antibiotics today, emerged several years before the widespread use of this antibiotic in humans, according to new research published in The Lancet Infectious Diseases. Low doses of penicillin routinely fed to livestock in the 1950s in North America and Europe may have encouraged antibiotic-resistant bacteria to evolve and spread, report scientists. Bacteria that can pass on genes resistant to ampicillin, one of the most commonly used antibiotics today, emerged several years before the widespread use of this antibiotic in humans, according to new research. Molecular analysis of historical samples of Salmonella by researchers at the Institut Pasteur (Paris, France) suggests that the ampicillin resistance gene (blaTEM-1) emerged in humans in the 1950s, several years before the antibiotic was released onto the pharmaceutical market. The findings also indicate that a possible cause was the common practice of adding low doses of penicillin to animal feed in the 1950s and 60s. The study comes just weeks after WHO called for the end to routine antibiotic use to promote growth and prevent disease in healthy farm animals.