Thirteen-lined ground squirrels (Spermophilus tridecemlineatus) harbor multiantibiotic-resistant bacteria.
ABSTRACT Whether wild-caught animals used for biomedical research carry antibiotic-resistant bacteria is not well studied. Thirteen- lined ground squirrels (Spermophilus tridecemlineatus) are small mammals used to study hibernation. These animals are captured from the wild or are born in laboratory animal facilities to wild-caught mothers. Because microorganisms harbored by 13-lined ground squirrels may be pathogenic to their caretakers and other laboratory animals, learning more about antibiotic resistance in these animals could be useful. In this study, tetracycline- and chloramphenicol-resistant Morganella morganii and multidrug resistant Stenotrophomonas maltophilia were isolated from the ceca of four 13-lined ground squirrels. These findings support further study of antibiotic-resistant bacterial populations in wild-caught mammals used as laboratory models.
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ABSTRACT: Many hibernating mammals suspend food intake during winter, relying solely on stored lipids to fuel metabolism. Winter fasting in these species eliminates a major source of degradable substrates to support growth of gut microbes, which may affect microbial community structure and host-microbial interactions. We explored the effect of the annual hibernation cycle on gut microbiotas using deep sequencing of 16S rRNA genes from ground squirrel cecal contents. Squirrel microbiotas were dominated by members of the phyla Bacteroidetes, Firmicutes and Verrucomicrobia. UniFrac analysis showed that microbiotas clustered strongly by season, and maternal influences, diet history, host age and host body temperature had minimal effects. Phylogenetic diversity and numbers of OTUs were lowest in late winter and highest in the spring after a 2-week period of refeeding. Hibernation increased relative abundance of Bacteroidetes and Verrucomicrobia, phyla that contain species capable of surviving on host-derived substrates such as mucins, and reduced relative abundance of Firmicutes, many of which prefer dietary polysaccharides. Hibernation reduced cecal short-chain fatty acid and ammonia concentrations, and increased and decreased concentrations of acetate and butyrate, respectively. These results indicate that the ground squirrel microbiota is restructured each year in a manner that reflects differences in microbial preferences for dietary versus host-derived substrates, and thus the competitive abilities of different taxa to survive in the altered environment in the hibernator gut.AJP Regulatory Integrative and Comparative Physiology 11/2012; DOI:10.1152/ajpregu.00387.2012 · 3.28 Impact Factor
Article: The antibiotic resistome.[Show abstract] [Hide abstract]
ABSTRACT: Antibiotics are essential for the treatment of bacterial infections and are among our most important drugs. Resistance has emerged to all classes of antibiotics in clinical use. Antibiotic resistance has, proven inevitable and very often it emerges rapidly after the introduction of a drug into the clinic. There is, therefore, a great interest in understanding the origins, scope and evolution of antibiotic resistance. The review discusses the concept of the antibiotic resistome, which is the collection of all genes that directly or indirectly contribute to antibiotic resistance. The review seeks to assemble current knowledge of the resistome concept as a means of understanding the totality of resistance and not just resistance in pathogenic bacteria. The concept of the antibiotic resistome provides a framework for the study and understanding of how resistance emerges and evolves. Furthermore, the study of the resistome reveals strategies that can be applied in new antibiotic discoveries.Expert Opinion on Drug Discovery 08/2010; 5(8):779-88. DOI:10.1517/17460441.2010.497535 · 3.47 Impact Factor
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ABSTRACT: The environments in which animals have evolved and live have profound effects on all aspects of their biology. Predictable rhythmic changes in the physical environment are arguably among the most important forces shaping the evolution of behavior and physiology of animals, and to anticipate and prepare for these predictable changes animals have evolved biological clocks. Unpredictable changes in the physical environment have important impacts on animal biology as well. The ability of animals to cope with and survive unpredictable perturbations depends on phenotypic plasticity and/or microevolution. From the time metazoans first evolved from their protistan ancestors they have lived in close association with a diverse array of microbes that have influenced, in some way, all aspects of the evolution of animal structure, function and behavior. Yet, few studies have addressed whether daily or seasonal rhythms may affect, or be affected by, an animal’s microbial symbionts. This survey highlights how biologists interested in the ecological and evolutionary physiology of animals whose lifestyles are influenced by environmental cycles may benefit from considering whether symbiotic microbes have shaped the features they study.Journal of Thermal Biology 08/2014; 44:78-84. DOI:10.1016/j.jtherbio.2014.02.015 · 1.54 Impact Factor