RESUMO
BACKGROUND: Vancomycin is frequently used as a last line of defence against infections due to multidrug-resistant Staphylococcus aureus (S. aureus). A recent finding described the acquisition of vancomycin-resistant S. aureus strains by the integration of an enterococcal plasmid containing the vanA operon into the S. aureus chromosome via homologous recombination involving a specific integration site called locus L2. METHODS: To characterise all mechanisms of acquisition of vanA, this study analysed the 15 706 S. aureus genomes to look for vanA and described its genetic environment. RESULTS: A complete vanA operon was found in 25 S. aureus strains isolated from 12 patients, including nine co-isolated with vancomycin-resistant Enterococcus strains. VanA was found within transposon Tn1546-like elements on 17 plasmids and eight chromosomes. VanA might be acquired through conjugation of enterococcal and staphylococcal plasmids, transposition of Tn1546 carrying vanA and plasmid integration into the chromosome. Further, L2 was detected in 2087 genomes (13.3%) of S. aureus strains across different continents. Six potential chromosomal hotspots for integration of the entire vanA-containing enterococcal plasmid were identified by homologous recombination via L2. CONCLUSIONS: These findings suggest that the recently described scenario in a New York patient could be reproduced anywhere. Surveillance of this possibility is mandatory, especially in patients with vancomycin-resistant Enterococcus infection or colonisation.
Assuntos
Proteínas de Bactérias , Carbono-Oxigênio Ligases , Elementos de DNA Transponíveis , Genoma Bacteriano , Óperon , Plasmídeos , Infecções Estafilocócicas , Staphylococcus aureus , Resistência a Vancomicina , Humanos , Plasmídeos/genética , Resistência a Vancomicina/genética , Staphylococcus aureus/genética , Staphylococcus aureus/efeitos dos fármacos , Elementos de DNA Transponíveis/genética , Proteínas de Bactérias/genética , Carbono-Oxigênio Ligases/genética , Genoma Bacteriano/genética , Infecções Estafilocócicas/microbiologia , Antibacterianos/farmacologia , Vancomicina/farmacologiaRESUMO
BACKGROUND: The Grand Magal of Touba (GMT) associates with risks of infection, but no study on the circulation of resistant bacteria has yet been conducted. MATERIALS AND METHODS: qPCR was performed on rectal samples from GMT pilgrims between 2018 and 2021, before and after their participation in the gathering. Rectal samples from between 2018 and 2020 were also cultured on specific media, and antibiotic susceptibility testing was performed. RESULTS: Forty-one of the 296 (13.8%) pilgrims had at least one gastrointestinal symptom and 91/290 (31.4%) acquired pathogenic bacteria, mostly Escherichia coli. A total of 54.7% of pilgrims reported washing their hands more frequently than usual and 89.2% used soap. One hundred and five (36.2%) acquired at least one resistance gene, notably CTX-M A (21.0%), SHV (16.5%) and TEM (8.2%). The strains isolated by culture were mostly E. coli. These bacteria were found to be sensitive to carbapenems and resistant to amoxicillin and amoxicillin-clavulanic acid. The acquisition of enteroaggregative E. coli was independently associated with CTX-M A and TEM acquisition. CONCLUSION: Pilgrims presented a risk for acquisition of CTX-M A after the GMT. Surveillance of the prevalence of resistant bacteria and the occurrence of associated clinical infections among pilgrims are necessary in the future.