Aims:  To survey the presence of indigenous and nonindigenous foodborne bacterial pathogens in displayed prepacked portions of fresh marine fish. Methods and Results:  A survey of 50 different samples of fresh marine fish (conger, swordfish, sole, grouper and whiting) was conducted over a period of 5 months. Trays of fillets and steaks were obtained at retail level and tested for foodborne bacterial pathogens. Vibrio cholerae and Salmonella were not detected. Two samples (4%) yielded Vibrio strains carrying a DNA fragment specific for Vibrio parahaemolyticus, but resulted negative to PCR amplification of the virulence‐related tdh gene. Levels of motile Aeromonas ranging from 2·29 to 7·20 log CFU g−1 were found in 31 (62%) samples. All fish portions were positive for the Aeromonas hlyA gene and 38 for both aerA and hlyA genes, which may contribute to diarrhoea‐related virulence. The incidence of Listeria monocytogenes was 10%. Levels of Staphylococcus aureus lower than 2 log CFU g−1 were found in 15 (30%) samples. Numbers of presumptive Clostridium perfringens ranging from 1·82 ± 0·22 to 4·26 ± 1·25 log CFU g−1 were detected in 42 (84%) samples. Edwardsiella tarda was detected in two samples of grouper fillets. Conclusions:  Displayed portions of raw fish carried bacteria that can cause foodborne disease. The risk posed by fresh fish when properly cooked is low, but high when destined to be consumed raw, undercooked or very lightly processed. Significance and Impact of the Study:  This study revealed that raw fish sold in Spain could be a source of foodborne bacterial pathogens. Improvements in handling and processing are needed to minimize the prevalence of pathogenic bacteria.

The aim of this study was the characterization of a collection of 8 methicillin-resistant Staphylococcus aureus (MRSA) isolates, obtained from samples of fresh cheese (Doble Crema) produced from raw cow milk in small dairies in Colombia. All the isolates harbored the mecA and Panton-Valentine leukocidin (PVL) genes, presented with SCCmec type IV, and belonged to multilocus sequence type 8 and spa type 024. Seven isolates presented 3 closely related pulsed-field gel electrophoresis profiles. Three of them carried the staphylococcal enterotoxin B gene. The isolates were resistant to cefoxitin, oxacillin, penicillin, and ampicillin and susceptible to all non-β-lactams antibiotics tested, with minimum inhibitory concentration values for oxacillin of 4 to 8mg/L. The isolates belonged to the community-acquired MRSA group, suggesting a human source of contamination. The risk of human infection by MRSA via contaminated foods is considered low, but contaminated food commodities can contribute to the worldwide dissemination of clones of community-acquired MRSA.

No abstract

Desde el punto de vista de salud pública, el patotipo de Escherichia coli Productor de Toxina Shiga (STEC) es el más relevante en la actualidad, debido a los síntomas y mortalidad que ocasiona, además de su demostrada multirresistencia antibiótica. El principal reservorio de esta bacteria es el ganado vacuno, razón por la cual la ingestión de alimentos derivados de estos animales de abasto es una de las principales fuentes de infección para el ser humano. El objetivo de este estudio fue determinar el efecto antibacteriano de aceites esenciales y extractos de plantas no diluidos frente a cepas STEC in vitro y en muestras de carne. Los resultados del ensayo in vitro revelaron que el aceite esencial de Lippia origanoides fue el que exhibió mayor efecto antimicrobiano evidenciando, en promedio, halos de inhibición en placa de 24,58 mm y una Concentración Mínima Bactericida de 1,8%. Adicionalmente, no se obtuvo crecimiento bacteriano luego de inocular un cocktail de cepas STEC en muestras de carne refrigerada adicionadas con este aceite esencial, durante un periodo de incubación de nueve días. Por tanto, el uso del aceite esencial de Lippia origanoides puede ser un método alternativo de control para este patógeno en carnes. Este es el primer reporte de inhibición de cepas STEC no O157 con Lippia origanoides en muestras de carne.