ArmA methyltransferase in monophasic Salmonella enterica isolated from food
Investigación publicada en Antimicrobial Agents and Chemotherapy
1 de noviembre de 2011
The 16S rRNA methyltransferase ArmA is a worldwide emerging determinant that confers high-level resistance to most clinically relevant aminoglycosides. We report the identification and characterization of a multidrug resistant Salmonella enterica subspecies I. 4,12:i:- isolate recovered from chicken meat sampled in a supermarket on February 2009 in La Reunion, a French island in the Indian Ocean. Susceptibility testing showed an unusually high-level resistance to gentamicin as well as to ampicillin, third generation cephalosporins and amoxicillin/clavulanate. Molecular analysis of the 16S rRNA methyltransferases revealed presence of the armA gene together with blaTEM-1, blaCMY-2 and blaCTX-M-3. All these genes could be transferred en bloc through conjugation into E. coli at a frequency of 1 x 10-5 CFU/donor. Replicon typing and S1-PFGE revealed that the armA gene was borne on a broad-host-range IncP plasmid, pB1010, of approximately 150 kb in size. To elucidate how armA had integrated in pB1010, a PCR mapping strategy was developed for Tn1548, the genetic platform for armA. The gene was embedded in a Tn1548-like structure, albeit with a deletion of the macrolide resistance genes and an IS26 inserted within the mel gene. To our knowledge, this is the first report of the ArmA methyltransferase in the East of Africa and in food, showing a novel route of transmission for this resistance determinant. Further surveillance in food-borne bacteria will be crucial to determine the role of food in the spread of 16S rRNA methyltransferase genes worldwide
Granier SA., Hidalgo L., San Millan A., Escudero JA., Gutierrez B., Brisabois A. y Gonzalez-Zorn B..
 | Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM). |
| Departamento de Sanidad Animal. Facultad de Veterinaria. Universidad Complutense (UCM). |
 | Laboratoire de Sécurité des Aliments. Agence Nationale de Sécurité Sanitaire de l´alimentation, de l´environnement et du travail (ANSES). |
