No question, the antibiotic issue continues to haunt food-animal production. Yet there remains debate as to the scientific connection to antibiotic use in animals and potential bacterial antibiotic resistance.
A study by A.E. van den Boggaard of the Department of Medical Microbiology at University of Maastricht in Netherlands has reported the ability of bambermycin to reduce the development of multi-resistant, intestinal bacteria in food animals under field conditions.
Bambermycin, a feed-grade antibiotic used exclusively in animal production, had been shown in previous studies to selectively inhibit the transfer of certain plasmids between E. coli and other bacterial species under laboratory conditions.
The study involved three groups of animals: a non-medicated/negative control group; a group treated with avoparcin as a positive control and the bambermycin group. All groups were housed in similar settings and shortly thereafter inoculated with multi-resistant field strains of swine origin E. coli.
The overall prevalence and degree of resistance to common therapeutic antibiotics increased significantly in the avoparcin and non-medicated group. Vanco-mycin-resistant enterococci increased markedly in the avoparcin-fed group. Vanco- mycin-resistant enterococci were present in typical numbers among animals in the non-medicated and bambermycin groups.
The researchers concluded that the use of bambermycin as an antimicrobial performance promoter suppressed the growth, enhancement and dissemination of multi-resistant E. coli. Since neither bambermycin nor any related molecule is used therapeutically, there is no cross-resistance with therapeutic antibiotics and no transmissible resistance has been shown.