AUTHOR=Hormeño Lorena , Ugarte-Ruiz María , Palomo Gonzalo , Borge Carmen , Florez-Cuadrado Diego , Vadillo Santiago , Píriz Segundo , Domínguez Lucas , Campos Maria J. , Quesada Alberto 

TITLE=ant(6)-I Genes Encoding Aminoglycoside O-Nucleotidyltransferases Are Widely Spread Among Streptomycin Resistant Strains of Campylobacter jejuni and Campylobacter coli

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02515

DOI=10.3389/fmicb.2018.02515

ISSN=1664-302X

ABSTRACT=<p>Thermotolerant <italic>Campylobacter</italic> species <italic>C. jejuni</italic> and <italic>C. coli</italic> are actually recognized as the major bacterial agent responsible for food-transmitted gastroenteritis. The most effective antimicrobials against <italic>Campylobacter</italic> are macrolides and some, but not all aminoglycosides. Among these, susceptibility to streptomycin is reduced by mutations in the ribosomal RPSL protein or by expression of ANT(6)-I aminoglycoside O-nucleotidyltransferases. The presence of streptomycin resistance genes was evaluated among streptomycin-resistant <italic>Campylobacter</italic> isolated from humans and animals by using PCR with degenerated primers devised to distinguish <italic>ant(6)-Ia</italic>, <italic>ant(6)-Ib</italic> and other <italic>ant</italic>-like genes. Genes encoding ANT(6)-I enzymes were found in all possible combinations with a major fraction of the isolates carrying a previously described <italic>ant</italic>-like gene, distantly related and belonging to the new <italic>ant(6)-I</italic> sub-family <italic>ant(6)-Ie</italic>. Among <italic>Campylobacter</italic> isolates, <italic>ant(6)-Ie</italic> was uniquely found functional in <italic>C. coli</italic>, as shown by gene transfer and phenotype expression in <italic>Escherichia coli</italic>, unlike detected coding sequences in <italic>C. jejuni</italic> that were truncated by an internal frame shift associated to RPSL mutations in streptomycin resistant strains. The genetic relationships of <italic>C. coli</italic> isolates with ANT(6)-Ie revealed one cluster of strains presented in bovine and humans, suggesting a circulation pathway of <italic>Campylobacter</italic> strains by consuming contaminated calf meat by bacteria expressing this streptomycin resistance element.</p>