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Previous issue date: 2013-09-30 / Salmonella enterica is considered an important zoonotic pathogen that can be responsible by losses in animal production, especially in poultry husbandry. Different classes of antimicrobials have been used as a prophylactic and/or therapeutic in poultry production, highlighting the quinolones, which also are indicated for human use. The wide use of these antimicrobials may contribute to the selection of microorganisms resistant to these drugs. Resistance to quinolones has been assigned to mutations in genes encoding DNA gyrase and topoisomerase IV, in addition to being associated with the presence of plasmid-mediated quinolone resistance (PMQR), especially encoded by qnr and aac(6')-Ib-cr genes. Thus, the aim of this study was to evaluate the presence of efflux pump systems involved in the resistance to quinolones using the efflux pump inhibitor carbonyl cyanide m-chlorophenylhydrazone (CCCP), and identify the presence of resistance determinants to quinolones in isolates of S. enterica from poultry-related material. For this, 36 S. enterica strains resistant to quinolones were used. The reduction of the activity of efflux pump systems was detected in 66.7% of isolates tested for nalidixic acid and ciprofloxacin with addition of CCCP. Mutation in DNA gyrase was determined by sequencing and analysis of the gyrA gene, and qnr (A, B, D and S) and aac(6')-Ib-cr genes were detected by PCR. Analysis of the gyrA gene sequences in isolates phenotypically resistant to quinolones identify the presence of mutation leading to the alteration Ser83→Phe and Asp87→Gly, Asn or Tyr in 38,9% and 22,2%, respectively. Plasmid profile analysis showed nine profiles with plasmids that ranged from ~2 kb to ~50 kb, and PMQR genes were found in 22.2% of S. enterica isolates. qnrA and qnrB genes were detected in 11.1% and 5.5% of isolates, respectively, and qnrS was found in 2.7%. None qnrD gene was found in the isolates tested. aac(6')-Ib-cr gene was detected in 8.3% of the isolates. To our knowledge, this study reports for the first time mutations in gyrA in S. Worthington from poultry, as well as this is the first report of the presence of qnrA, qnrS and aac(6')-Ib-cr in S. enterica isolated from samples related to poultry production chain in Brazil. The presence of resistance determinants to quinolones in S. enterica isolates from poultry leads to concern regarding to potential resistance selection due to the use of these antimicrobials in animal production. / A Salmonella enterica ? considerada um importante pat?geno zoon?tico que pode ser respons?vel por perdas na produ??o animal, especialmente na cria??o de aves. Diferentes classes de antimicrobianos t?m sido utilizadas de forma profil?tica e/ou terap?utica na produ??o av?cola, entre elas destacam-se as quinolonas, que tamb?m t?m indica??o para uso humano. A ampla utiliza??o destes antimicrobianos pode contribuir para a sele??o de microrganismos resistentes a estes f?rmacos. A resist?ncia a quinolonas tem sido atribu?da a muta??es nos genes da DNA girase e da topoisomerase IV, al?m de estar associada ? presen?a de determinantes de resist?ncia carreados por plasm?deos (PMQR), especialmente aqueles codificados pelos genes qnr e aac(6 )-Ib-cr. Desta forma, o objetivo do presente trabalho foi avaliar a presen?a de sistemas de bombas de efluxo envolvidos na resist?ncia a quinolonas utilizando o inibidor Cianeto de Carbonila Clorofenilhidrazona (CCCP), bem como identificar determinantes de resist?ncia a quinolonas em isolados de S. enterica de origem av?cola. Para tanto, foram utilizados 36 isolados de S. enterica resistentes quinolonas. A redu??o na atividade dos sistemas de bombas de efluxo foi observada em 66,7% dos isolados testados para o ?cido nalid?xico e para a ciprofloxacina com adi??o do CCCP. Muta??es na DNA girase foram determinadas por sequenciamento e an?lise do gene gyrA, e os genes qnr (A, B, D e S) e aac(6 )-Ib-cr foram detectados atrav?s de PCR. A an?lise das sequ?ncias do gene gyrA nos isolados fenotipicamente resistentes a quinolonas identificou a presen?a de muta??o levando ? altera??o Ser83→Phe e Asp87→Gly, Asn ou Tyr em 38,9% e 22,2%, respectivamente. A an?lise do perfil plasmidial revelou nove perfis com plasm?deos que variaram de ~2 kb at? ~50 kb e os genes PMQR foram encontrados em 22,2% dos isolados de S. enterica. O gene qnrA e o qnrB foram detectados em 11,1% e 5,5% dos isolados, respectivamente, e o gene qnrS em 2,7%. O gene qnrD n?o foi encontrado em nenhum dos isolados testados. O gene aac(6 )-Ib-cr foi detectado em 8,3% dos isolados. At? onde se sabe, este trabalho relata pela primeira vez muta??es no gene gyrA em S. Worthington de origem avi?ria, bem como, este ? o primeiro relato da presen?a dos genes qnrA, qnrS e aac(6 )-Ib-cr em cepas de S. enterica isoladas de amostras relacionadas com a cadeia produtiva de frangos no Brasil. A presen?a de determinantes de resist?ncia a quinolonas em isolados de S. enterica de origem avi?ria alerta para a poss?vel sele??o de resist?ncia pelo uso destes antimicrobianos na produ??o animal.
| Identifer | oai:union.ndltd.org:IBICT/oai:tede2.pucrs.br:tede/5504 |
| Date | 30 September 2013 |
| Creators | Drescher, Guilherme |
| Contributors | Oliveira, Silvia Dias de |
| Publisher | Pontif?cia Universidade Cat?lica do Rio Grande do Sul, Programa de P?s-Gradua??o em Biologia Celular e Molecular, PUCRS, BR, Faculdade de Bioci?ncias |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Unknown |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da PUC_RS, instname:Pontifícia Universidade Católica do Rio Grande do Sul, instacron:PUC_RS |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 8198246930096637360, 600, 600, 36528317262667714 |
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