Biofilm formation by Salmonella Enteritidis at different incubation temperatures

Background: The genus Salmonella, associated with poultry products, is considered the leading cause of foodborne outbreaks in humans in many countries. In Brazil, Salmonella Enteritidis (SE) is the serovar remains as one most frequentlyisolated from humans, and it is also a major serovar found in animals, food, animal feed, and environmental samples, despiteall the efforts to control this pathogen. Also, the bacterium is able to form biofilms on different surfaces, protecting cellsfrom both cleaning and sanitizing procedures in the food industries. This study aimed to verify the ability of SalmonellaEnteritidis isolates to form biofilm on polystyrene at different incubation temperatures.Materials, Methods & Results: A total of 171 SE samples were isolated from foodborne outbreaks (foods and stool cultures) and poultry products between 2003 and 2010. The biofilm-forming ability of samples was measured at four differenttemperatures (3°C, 9ºC, 25ºC, and 36ºC), for 24 h, simulating temperatures usually found in poultry slaughterhouses. Later,200 μL of each bacterial suspension was inoculated, in triplicate, onto 96-well, flat-bottomed sterile polystyrene microtiterplates, washed, after that, the biofilm was fixed with methanol. The plates were dried at ambient temperature, stained with2% Huckers crystal violet. Afterwards, absorbance was read using an ELISA plate reader and the optical density (OD)of each isolate was obtained by the arithmetic mean of the absorbance of three wells and this value was compared withthe mean absorbance of negative controls (ODnc). The following classification was used for the determination of biofilmformation: no biofilm production, weak biofilm production, moderate biofilm production and strong biofilm production.Results demonstrated all isolates from stool cultures and foods involved in foodborne outbreaks, at least one of the fourtemperatures tested, were able to form biofilm...(AU)

Biofilm formation by Salmonella Enteritidis at different incubation temperatures

Background: The genus Salmonella, associated with poultry products, is considered the leading cause of foodborne outbreaks in humans in many countries. In Brazil, Salmonella Enteritidis (SE) is the serovar remains as one most frequentlyisolated from humans, and it is also a major serovar found in animals, food, animal feed, and environmental samples, despiteall the efforts to control this pathogen. Also, the bacterium is able to form biofilms on different surfaces, protecting cellsfrom both cleaning and sanitizing procedures in the food industries. This study aimed to verify the ability of SalmonellaEnteritidis isolates to form biofilm on polystyrene at different incubation temperatures.Materials, Methods & Results: A total of 171 SE samples were isolated from foodborne outbreaks (foods and stool cultures) and poultry products between 2003 and 2010. The biofilm-forming ability of samples was measured at four differenttemperatures (3°C, 9ºC, 25ºC, and 36ºC), for 24 h, simulating temperatures usually found in poultry slaughterhouses. Later,200 μL of each bacterial suspension was inoculated, in triplicate, onto 96-well, flat-bottomed sterile polystyrene microtiterplates, washed, after that, the biofilm was fixed with methanol. The plates were dried at ambient temperature, stained with2% Hucker’s crystal violet. Afterwards, absorbance was read using an ELISA plate reader and the optical density (OD)of each isolate was obtained by the arithmetic mean of the absorbance of three wells and this value was compared withthe mean absorbance of negative controls (ODnc). The following classification was used for the determination of biofilmformation: no biofilm production, weak biofilm production, moderate biofilm production and strong biofilm production.Results demonstrated all isolates from stool cultures and foods involved in foodborne outbreaks, at least one of the fourtemperatures tested, were able to form biofilm...

Biofilm former Salmonella enteritidis are multiresistant to antibiotics / Salmonella Enteritidis formadoras de biofilmes são multirresistentes a antimicrobianos

Background: The Salmonella Enteritidis is one of the most isolated pathogens in outbreaks of foodborne illness, whichcan occur due to various factors such as cooking temperature, inadequate storage and cross-contamination. The choice ofthe appropriate disinfectant in food industries is essential to prevent the spread of contamination and control of biofilmson surfaces. It is also extremely important the concern with resistance to antimicrobials used both as growth promotersand in human and animal treatments, which may generate a selective pressure favoring the emergence of resistant bacteria.Materials, Methods & Results: Twenty samples of Salmonella Enteritidis were tested, 10 from outbreaks of foodbornediseases and 10 of poultry origin, as for the formation of biofilms, antibiotic resistance and sanitizers. The samples werestored frozen in BHI with 20% glycerol. For reactivation were incubated in BHI broth, plated on XLD agar and subsequentlyperformed biochemical tests to check purity. Firstly were evaluated for biofilm formation on polystyrene at temperature of36 ± 1ºC. We tested the sanitizing resistance to biguanide concentrations 0.6%, 1.0% and 1.5%, peracetic acid at concentrations 0.1%, 0.5% and 1.0%, and quaternary ammonia at concentrations of 0.3%, 1.0% and 2.0%. For tests of antimicrobialresistance the cultures were evaluated front 10 μg ampicillin, 30 μg cephalexin, 30 μg chloramphenicol, 5 μg enrofloxacin,15 μg erythromycin, 30 μg neomycin, 25 μg sulphazotrim, 300 μg sulfonamides. According to the results, 25% of sampleswere strongly biofilm formers, 35% moderately formers, 35% weakly formers and 10% not biofilm formers. In sanitizers, quaternary ammonia and peracetic acid were effective at all concentrations and at all times, but tests with biguanide...

Biofilm former Salmonella enteritidis are multiresistant to antibiotics / Salmonella Enteritidis formadoras de biofilmes são multirresistentes a antimicrobianos

Background: The Salmonella Enteritidis is one of the most isolated pathogens in outbreaks of foodborne illness, whichcan occur due to various factors such as cooking temperature, inadequate storage and cross-contamination. The choice ofthe appropriate disinfectant in food industries is essential to prevent the spread of contamination and control of biofilmson surfaces. It is also extremely important the concern with resistance to antimicrobials used both as growth promotersand in human and animal treatments, which may generate a selective pressure favoring the emergence of resistant bacteria.Materials, Methods & Results: Twenty samples of Salmonella Enteritidis were tested, 10 from outbreaks of foodbornediseases and 10 of poultry origin, as for the formation of biofilms, antibiotic resistance and sanitizers. The samples werestored frozen in BHI with 20% glycerol. For reactivation were incubated in BHI broth, plated on XLD agar and subsequentlyperformed biochemical tests to check purity. Firstly were evaluated for biofilm formation on polystyrene at temperature of36 ± 1ºC. We tested the sanitizing resistance to biguanide concentrations 0.6%, 1.0% and 1.5%, peracetic acid at concentrations 0.1%, 0.5% and 1.0%, and quaternary ammonia at concentrations of 0.3%, 1.0% and 2.0%. For tests of antimicrobialresistance the cultures were evaluated front 10 μg ampicillin, 30 μg cephalexin, 30 μg chloramphenicol, 5 μg enrofloxacin,15 μg erythromycin, 30 μg neomycin, 25 μg sulphazotrim, 300 μg sulfonamides. According to the results, 25% of sampleswere strongly biofilm formers, 35% moderately formers, 35% weakly formers and 10% not biofilm formers. In sanitizers, quaternary ammonia and peracetic acid were effective at all concentrations and at all times, but tests with biguanide...(AU)