| Congresso Brasileiro de Microbiologia 2023 | Resumo: 790-2 | ||||
Resumo:The incidence of human salmonellosis caused by multidrug-resistant non-typhoidal Salmonella has been extensively discussed in recent decades, mainly due to the compromised effectiveness of most established antibiotics. In addition, the antimicrobial resistance genes in Salmonella may be incorporated on mobile genetic element (MGE), as integrons, that play an important role in their dissemination. Therefore, this study aimed to identify and characterize integrons in Salmonella isolates in silico, and to associate these MGE with the antimicrobial resistance patterns of the isolates. A total of 41 whole-genome sequencing data were obtained from a previous study, in which non-typhoidal Salmonella, isolated from a Brazilian pork production chain, were characterized. We analysed the trimmed paired-end reads with PlasmidSPAdes, to assemble extra-chromosomal genetic elements. In order to separate chromosomal and plasmid sequences, Bowtie2, Samtools and Bedtools were used to obtain mapped plasmid paired-end reads and unmapped genomic paired-end reads. We utilized SPAdes software to assemble contigs from the obtained genomic paired-end reads, and the all sequences were annotated using Prokaryotic Genome Annotation System (Prokka) software. Subsequently, the integrons were predicted using IntegronFinder software. Additionally, the gene sequences were compared against all integrons from INTEGRALL using the BLASTn program available on NCBI, and the predicted matched proteins were annotated by BLASTp against the NCBI's Bacteria (taxid:2) non-redundant protein database (query coverage ≥ 80%; identity ≥ 90%). Moreover, sequences containing integrons, which were not categorized as plasmids, were analyzed against the PLSDB plasmid database. We identified nine isolates with some integron, characterized as incomplete or complete. Only one integron, class 1, was identified in a non-plasmid contig. Six complete class 1 integrons were found, with streptomycin resistance genes (aadA1, aadA2) alone or downstream of a trimethoprim resistance gene (dfrA1, dfrA12), and some also containing resistance genes for sulfonamides (sul1, sul3) and chloramphenicol (cmlA1). One isolate showed the presence of a class 2 integron, containing dfrA1-sat2-aadA1 gene cassettes. Five isolates harbored CALINs – clusters attC but lacking integrases – with antimicrobial resistance genes typically found in integron structures. In all, integrons were observed among at four serotypes: Panama, Bredeney, Derby, and monophasic var. Typhimurium I 4,[5],12:i:-. In this work, integrons was predominantly identified in multidrug resistance isolates, and six of the seven gentamicin-resistant isolates had integrons. Therefore, carrying out regular monitoring of integrons in Salmonella isolates can provide important data to assess risks to human health, and thus seek to reduce the transmission of bacteria with resistance to antibiotics from animals to humans through the food chain. Palavras-chave: Antibiotic resistance, Gene cassettes, Gentamicin, Mobile genetic element, Plasmid Agência de fomento:CAPES, CNPq, FAPEMIG | |||||