Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2007
Publication Date: June 26, 2007
Citation: Stanton, T.B. 2007. P10 alternative uses and collateral effects of antimicrobials [abstract]. American Society for Microbiology Branch Meeting. p. 10 Technical Abstract: Throughout history and nature, antimicrobials have had applications in addition to treating diseases. Certain insects use antimicrobials as disinfectants. Ancient Nubians incorporated antibiotics in the manufacture of ‘booza’, a traditional alcoholic beverage in their culture. For the last four decades, antimicrobials have been used in agriculture to enhance the growth performance of farm animals. There is a growing awareness that antimicrobials, in nature and in the clinic, have collateral effects. Collateral effects can be unpredictable and are not necessarily associated with the ability of the antimicrobial to control or inhibit bacterial growth. At sub-inhibitory levels, certain antibiotics can serve as environmental signals, inducing changes in adaptive gene expression in exposed bacteria. Aminoglycosides can induce biofilm formation by Pseudomonas aeruginosa. Tetracyclines inhibit the breakdown of connective tissue associated with periodontal disease. In our laboratory, antimicrobials used in swine feed were examined for collateral effects. One of these, carbadox, at sub-MIC levels, induced production of a novel gene transfer agent (VSH-1) by the anaerobic, enteropathogenic spirochete Brachyspira hyodysenteriae. Carbadox-induced VSH-1 particles transferred resistance to macrolide and lincosamide antibiotics between strains of this spirochete. In terms of the human condition, antimicrobial collateral effects may be either desirable or undesirable. An awareness that collateral effects can occur should be part of the equation when considering recommendations or standards for prudent antibiotic use.