Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural phytoalexin synthesized by plants in response to stress. This compound has several beneficial documented properties, namely anti-inflammatory, antioxidant, neuroprotective and antimicrobial activities. In this study the antimicrobial activity of resveratrol against Listeria monocytogenes and Listeria innocua was investigated.
Arcobacter is considered an emerging enteric pathogen, commonly associated with diarrhea, abdominal pain and in some cases with bacteriemia. This genus is widely distributed, withfteen species identied to date, of which the most common is Arcobacter butzleri. Arcobacter spp. has been isolated from environmental, animal, food and human samples, but poultry is considered its main reservoir. The extended use of antibiotics for disease control in modern food animal production, leads to a spread of resistant pathogenic bacteria, and Arcobacter spp. is no exception to this rule. In this study, 43 A. butzleri isolates were obtained from poultry and environment samples at a Portuguese slaughterhouse, also three reference strains were included. All isolates were conrmed at species level by multiplex PCR; genomic DNAngerprints of all isolates were determined using Pulsed Field Gel Electrophoresis (PFGE) after enzymatic digestion with SmaI. Resistance proles to nine antibiotics were assessed by broth microdilution method. Fifteen unique and 11 common PFGEngerprints were identied among the 43 Arcobacter isolates studied, generating a total of 26 dierent PFGEngerprints. This data demonstrates the high genetic diversity observed among Arcobacter isolates. Concerning the antibiotic susceptibility, all isolates tested were susceptible to gentamycin and one strain presented resistance to chloramphenicol. In contrast, 24 of the 43 isolates (55.8%) were resistant to ciprooxacin. All the studied isolates presented resistance to multiple antibiotics simultaneously, especially to ampicillin, vancomycin, trimethoprim, piperacillin, cefoperazone and amoxicillin. The results showed that A. butzleri isolated in Portugal presents a high genetic diversity, but also show high levels of resistance to several antimicrobial agents, this fact could represent a potential health hazard for humans through food chain contamination.
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