Investigation of the prevalence of , and genes in strains with elevated tigecycline minimum inhibitory concentrations

Noémi Anikó Bartha (1) , József Sóki (1) , Edit Urbán (1) , Elisabeth Nagy (1)

1 University of Szeged [Szeged]

In this study, the antibiotic susceptibilities to tigecycline and tetracycline of 35 selected group strains were determined by Etest, and the presence of , , and genes was investigated by polymerase chain reaction (PCR). was detected in all 12 group isolates (100%) exhibiting elevated tigecycline minimum inhibitory concentrations (MICs) (≥8μg/mL) as well as the 8 strains (100%) with a tigecycline MIC of 4μg/mL, whilst and were present in 15% and 75% of these strains, respectively. All of these strains were fully resistant to tetracycline (MIC ≥ 16μg/mL). On the other hand, among the group of strains with tigecycline MICs<4μg/mL (15 isolates), , t and were found less frequently (73.3%, 13.3% and 46.7%, respectively). All but two strains harbouring the gene in this group were non-susceptible to tetracycline, with an MIC>4μg/mL. These data suggest that in most cases tigecycline overcomes the tetracycline resistance mechanisms frequently observed in strains. However, the presence of and genes in some of the strains exhibiting elevated MICs for tigecycline draws attention to the possible development and spread of resistance to this antibiotic agent among strains. The common occurrence of , , and genes together predicted the presence of the CTnDOT-like conjugative transposon in this collection of strains.

Mots clés: Tigecycline; Bacteroides; tetX; tetX1; tetQ

Domaines: Microbiologie et Parasitologie

Noémi Anikó Bartha, József Sóki, Edit Urbán, Elisabeth Nagy. Investigation of the prevalence of , and genes in strains with elevated tigecycline minimum inhibitory concentrations. International Journal of Antimicrobial Agents, 2011, 38 (6), pp.522. ⟨10.1016/j.ijantimicag.2011.07.010⟩. ⟨hal-00746419⟩