Molecular tools for the characterisation of antibiotic-resistant bacteria

Abstract

-This review will discuss a number of molecular tools which are currently used as well as some innovative approaches for the characterisation of antibiotic-resistant bacterial strains. Various methods involved in the detection and characterisation of genes and mutations associated with antibiotic resistance and that are used for strain typing as part of epidemiological studies, are described. Furthermore, a few examples are discussed in which the results of both gene and strain characterisation are combined to investigate the underlying mechanism of the spread of antibiotic resistance. Some of the available molecular techniques are heavily supported by the existence of databases on the Internet. These databases either contain a fast growing amount of sequence information or a large number of allelic or fingerprint profiles. The current progress in applied DNA technology and the ongoing projects on the elucidation of the whole genomic sequence of bacterial species have lead and will further lead to the development and application of sophisticated new strategies for the analysis of antibiotic resistant bacterial strains.antibiotic resistance / molecular detection / molecular typing / horizontal gene transfer / new approaches Résumé -Outils moléculaires pour la caractérisation de bactéries résistantes aux antibiotiques. Cette revue présente les outils moléculaires utilisés actuellement ainsi que des nouvelles approches pour la caractérisation de souches bactériennes résistantes aux antibiotiques. Différentes méthodes de détection et de caractérisation des gènes et des mutations impliqués dans la résistance aux antibiotiques, utilisées dans des études épidémiologiques, sont décrites. Quelques exemples sont présentés où sont associées les caractérisations du gène et de la souche bactérienne dans l'étude des mécanismes de diffusion de résistances aux antibiotiques. Certaines techniques moléculaires font

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

“…It is also interesting to note that strains showing the same macrorestriction pattern nevertheless exhibit genetic diversity when using other methods such as infrequent restriction site PCR (IRS-PCR) and amplified fragment length polymorphism (AFLP) [46]. The latter methods may be more discriminatory than PFGE and the usefulness and limits of each method are described by Aarts et al [1] in this special issue. The occurrence of the DT104 antibiotic resistance gene cluster in several clones would suggest horizontal transfer of the cluster and possibly of the entire SgiI among S. enterica Typhimurium strains.…”

Relatedness of Escherichia coli Strains with Different Susceptibility Phenotypes Isolated from Swine Feces during Ampicillin Treatment

“…Pulsed-field gel electrophoresis (PFGE) allows identification of strains by their molecular genotypes and has great value in epidemiological analysis, in the differentiation of pathogenic strains, and in monitoring the spread of such strains between communities (14,17,24). This method can also be used to evaluate the potential clonal spread of resistant strains (1,44). It has previously been used to investigate the dissemination and diversity of ampicillin-resistant commensal E. coli strains in cattle (22,23) and dogs (32).…”

Antimicrobial Resistance Genes Associated with Salmonella enterica Serovar Newport Isolates from Food Animals

“…Therefore, the increasing number of serovar Newport infections appears to be associated with the emergence and rapid dissemination of multidrugresistant (MDR) strains of serovar Newport (18). Multidrug resistance is often associated with mobile genetic elements (i.e., plasmids and transposons) that encode multiple specific resistance genes (1,12,13,17,19).…”