Dissemination of the strA-strB streptomycin-resistance genes among commensal and pathogenic bacteria from humans, animals, and plants.
Gene transfer within bacterial communities has been recognized as a major contributor in the recent evolution of antibiotic resistance on a global scale. The linked strA-strB genes, which encode streptomycin-inactivating enzymes, are distributed worldwide and confer streptomycin resistance in at least 17 genera of gram-negative bacteria. Nucleotide sequence analyses suggest that strA-strB have been recently disseminated. In bacterial isolates from humans and animals, strA-strB are often linked with the suIII sulfonamide-resistance gene and are encoded on broad-host-range nonconjugative plasmids. In bacterial isolates from plants, strA-strB are encoded on the Tn3-type transposon Tn5393 which is generally borne on conjugative plasmids. The wide distribution of the strA-strB genes in the environment suggests that gene transfer events between human, animal, and plant-associated bacteria have occurred. Although the usage of streptomycin in clinical medicine and animal husbandry has diminished, the persistence of strA-strB in bacterial populations implies that factors other than direct antibiotic selection are involved in maintenance of these genes.
Sundin
G W
GW
Department of Microbiology and Immunology, University of Illinois-Chicago 60612, USA.
Bender
C L
CL
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D005075:Biological Evolution; D002874:Chromosome Mapping; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics*; D018014:Gene Transfer Techniques; D005798:Genes, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D010944:Plants / Q000382:microbiology; D012093:Replicon; D013307:Streptomycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D013307:Streptomycin