Change Route of Delivery to Mitigate Antibiotic Resistance, Authors Say
Oral ingestion linked to increased resistance (June 26)
New research suggests that the rapid rise of antibiotic resistance correlates with oral ingestion of antibiotics, raising the possibility that other routes of administration could reduce the spread of resistance. The report appeared online in Antimicrobial Agents and Chemotherapy.
“For more than 40 years, a few doses of penicillin were enough to take care of deadly bacterial infections,” said researcher Dr. Hua Wang. But since the 1980s, antibiotic resistance has been spreading rapidly, disabling once-powerful agents.
In earlier research, the investigators found a large cache of antibiotic resistance genes carried by nonpathogenic bacteria in many ready-to-consume food items. They also reported rapid development of resistant bacteria shortly after birth in infants who had not been exposed to antibiotics, suggesting that the gastrointestinal (GI) tract played a critical role in spreading resistance.
In the new study, the researchers inoculated lab mice with either Enterococcus species or Escherichia coli carrying specific resistance genes. The mice were then given tetracycline or ampicillin antibiotics, either orally or via injection. Oral administration of antibiotics resulted in a rapid rise of resistance genes, as measured in the animals’ feces. Resistance spread much less and more slowly when the mice received antibiotics via injection.
Convenient alternatives to oral antibiotics might include transdermal administration via a patch or other devices, said Wang.
He suggests that it should not be surprising that oral administration would abet the spread of resistance genes, since this route, unlike injection, directly exposes the vast population of GI bacteria to antibiotics. The resulting resistant microbes then get transmitted to the environment via feces. From there, bacteria containing resistance genes once again gain entry to the food supply via livestock or via produce that has been exposed to manure from industrial livestock, as well as contaminated waste and soil, in a vicious cycle.
“Revealing this key risk factor is exciting because we have options other than oral administration, including convenient ones, for giving antibiotics,” Wang said.
Source: American Society for Microbiology; June 26, 2013.