RESUMEN
In this study, we described the comparison among pulsed-field gel electrophoresis (PFGE), random amplified polymorphic DNA (RAPD), ribotyping, and PCR-ribotyping methods for subtyping Salmonella Enteritidis isolated from an industrial chicken production chain. One hundred and eight S. Enteritidis were isolated at all stages of poultry meat processing plant. These isolates were pheno- and genotypically characterized by using antimicrobial susceptibility test, phage typing, RAPD, PFGE, ribotyping, and PCR-ribotyping. The highest antibiotic resistance rates were observed for enrofloxacin (18.5%) followed by furazolidone (15.7%), cefoxitin (1.8%), ciprofloxacin, and ampicillin with 0.9% each one, while seven isolates (6.4%) were pan-susceptible. Most strains belonged to the globally disseminated phage type PT4 (n = 74; 69.2%). Additionally, we identified strains belonging to phage types PT1 (n = 19; 17.8%) and PT7a (n = 14; 13.1%). Moreover, our results showed that these four molecular methods indicate similar results showing high similarity (≥ 90%) among S. Enteritidis strains, suggesting that these isolates appear to be from a common ancestor being spread at all stages of the poultry production chain. In summary, the combined molecular approaches of these methods remain a suitable alternative to efficiently subtyping S. Enteritidis in the absence of high-resolution genotyping methods and these results may serve as a baseline study for development of mitigation strategies.
Asunto(s)
Pollos/microbiología , Salmonelosis Animal/microbiología , Salmonella enteritidis/clasificación , Animales , Antibacterianos/farmacología , Técnicas de Tipificación Bacteriana , Tipificación de Bacteriófagos , Brasil , ADN Bacteriano/genética , Electroforesis en Gel de Campo Pulsado , Pruebas de Sensibilidad Microbiana , Reacción en Cadena de la Polimerasa , Técnica del ADN Polimorfo Amplificado Aleatorio , Ribotipificación , Salmonella enteritidis/efectos de los fármacosRESUMEN
In recent years, an increase in the occurrence of antimicrobial resistance among Salmonella enterica has been observed in several countries, which is worrisome because S. enterica is one of the most common causes of human gastroenteritis worldwide. The aim of this study was to characterize class 1 integrons and antibiotic resistance genotypes in Salmonella enterica isolates recovered from foodstuff and related sources. Nineteen multidrug-resistant (MDR) Salmonella enterica isolates were recovered. Higher resistance rates to tetracycline (90 percent), streptomycin (80 percent), sulfamethoxazole-trimethoprim (80 percent), ampicillin (60 percent) and nalidixic acid (70 percent) were related to the presence of the tetA, aadA, sul1/sul2, blaTEM-1 genes, and a codon mutation at position 83 of the gyrA gene, respectively. Class 1 integrons harboring aadA, blaTEM-1, sul1 or dhfr1 genes were detected in nine (45 percent) Salmonella enterica strains belonging to serotypes Brandenburg, Panama, Agona, Mbandaka and Alachua. Finally, clonal dissemination of S. Panama, S. Derby and S. Mbandaka was confirmed by PFGE. Detection of clonally related MDR Salmonella enterica suggests that endemic serotypes can be supported by class 1 integron-borne gene cassettes and/or mutations in drug targets. Emergence and dissemination of multidrug-resistant Salmonella enterica can have a major public health impact in an environment where large-scale suppliers ship their products.
RESUMEN
In recent years, an increase in the occurrence of antimicrobial resistance among Salmonella enterica has been observed in several countries, which is worrisome because S. enterica is one of the most common causes of human gastroenteritis worldwide. The aim of this study was to characterize class 1 integrons and antibiotic resistance genotypes in Salmonella enterica isolates recovered from foodstuff and related sources. Nineteen multidrug-resistant (MDR) Salmonella enterica isolates were recovered. Higher resistance rates to tetracycline (90%), streptomycin (80%), sulfamethoxazole-trimethoprim (80%), ampicillin (60%) and nalidixic acid (70%) were related to the presence of the tetA, aadA, sul1/sul2, bla TEM-1 genes, and a codon mutation at position 83 of the gyrA gene, respectively. Class 1 integrons harboring aadA, bla TEM-1, sul1 or dhfr1 genes were detected in nine (45%) Salmonella enterica strains belonging to serotypes Brandenburg, Panama, Agona, Mbandaka and Alachua. Finally, clonal dissemination of S. Panama, S. Derby and S. Mbandaka was confirmed by PFGE. Detection of clonally related MDR Salmonella enterica suggests that endemic serotypes can be supported by class 1 integron-borne gene cassettes and/or mutations in drug targets. Emergence and dissemination of multidrug-resistant Salmonella enterica can have a major public health impact in an environment where large-scale suppliers ship their products.
RESUMEN
Salmonella is one of the most important agents of foodborne disease in Brazil and in other countries, with meat and meat products being identified as important vehicles of salmonelosis. A total of 54 Salmonella strains isolated from a commercial salami processing line were first serotyped and then their antibiotic resistance and macro restriction profiles were determined. 11.1 percent of the strains showed resistance to 3 or more antibiotics with profile AmpCStxTe being the most frequent. PFGE generated 9 and 12 profiles with enzymes XbaI and SpeI, respectively. It was observed that different serotypes of Salmonella could be found in the different steps of the processing line. The genetic profile of the strains had low relationship indicating the genetic diversity of the tested strains.
Salmonella é um dos principais agentes de enfermidades transmitidas por alimentos (ETA) no Brasil e em outros países, sendo os derivados cárneos frequentemente associados como veículos de surtos de salmonelose. Um total de 54 cepas de Salmonella sp., isoladas a partir de amostras de salame coletadas nas diferentes etapas de uma linha de produção industrial, foram sorotipadas e posteriormente caracterizadas quanto a sua sensibilidade a antimicrobianos e perfil PFGE. Entre as cepas avaliadas, 11,1 por cento apresentaram resistência a três ou mais dos antimicrobianos, sendo o perfil AmpCStxTe mais freqüente. Foram obtidos 9 e 12 perfis PFGE, empregando-se as enzimas XbaI e SpeI, respectivamente. Os perfis de ambas as enzimas foram agrupados, obtendo-se 12 perfis PFGE combinados que puderam ser separados em dois grupos empregando-se a análise de UPGMA. A linha de produção industrial de salame avaliada apresentou etapas em que há contaminação por diferentes sorotipos de Salmonella sp. Os perfis genéticos encontrados indicam origens distintas para muitas cepas estudadas, uma vez que estes foram pouco relacionados entre si.
