Single- and Multispecies Biofilms by Escherichia coli, Staphylococcus aureus, and Salmonella spp. Isolated from Raw Fish and a Fish Processing Unit

Abstract

The consumption of fish by the Brazilian population is increasing. However, fish and seafood are highly perishable and can be contaminated with several microorganisms. In addition, the possibility of biofilm formation is a greater cause for concern. In this study, biofilm formation was evaluated in single- and multispecies cultures at 25°C for incubation periods of 0, 4, 8, 24, and 48h in stainless steel coupons (size, 1.0×1.0cm) immersed in tryptic soy broth. The characteristics of the formed biofilms after sanitizing by immersing the coupons in 200ppm sodium hypochlorite solution for 10min were also evaluated under the same experimental conditions but with some modifications. Biofilm structure was evaluated using scanning electron microscopy. Analysis of single-species biofilms indicated that all bacterial strains formed biofilms at different intervals without any statistically significant difference. However, comparison of the growth of single- and multispecies cultures indicated a significantly higher biofilm formation by the pure cultures. In multispecies biofilms, compared with the other microorganisms, growth of Salmonella spp. was significantly lower for all tested incubation periods; whereas, of Staphylococcus aureus was significantly higher than that of E. coli until 8h of incubation; the differences in growth were not significantly different after this incubation period. Sanitizing with sodium hypochlorite was effective because no cell growth was observed in the coupons that were treated with 200ppm sodium hypochlorite for 10min. This study demonstrated the ability of isolated microorganisms to form biofilms, reinforcing the need for food handling establishments to adopt good manufacturing practices, developing adequate protocols for cleaning and disinfecting surfaces and equipment used in food production, maintaining and replacing equipment when necessary.

First report ofEscherichia coliO157:H7 in ready‐to‐eat sushi

“…Considering this parameter, both E. coli O157:H7 sushi isolate and the control strain (NCTC 12900) had the ability to form biofilms with concentrations above 5 log CFU per cm of cells adhered to the stainless steel coupon at all temperatures tested in this study. Frozi et al () found biofilm counts in stainless steel of 7 log CFU per cm after 24 h of incubation at 25°C, using E. coli non‐O157 isolates from raw fish and from a fish processing unit, a similar result to that obtained in this study at temperatures of 25 and 37°C.…”

Interaction of Salmonella with E. coli and Proteus spp. in Biofilm Formation

“…The suppressive action Salmonella in dual biofilm formation was also described by Esteves et al [48] and described the poor outcompete manner of E.coli over the Salmonella strains. The significantly less biofilm-forming ability of SAL 1+SAL 3 as dual culture also corroborates with previous findings of Gkana et al [49] and Frozi et al [50], who speculated the lower biofilm-forming ability of Salmonella as dual cultures. However, the observed low biofilm capabilities or same biofilm capabilities of Salmonella and its interaction in different time points (Table 3) may be due to strain-dependent different properties, such as EPS production, presence of either flagella or fimbriae, etc.…”

Decoding antibacterial and antibiofilm properties of cinnamon and cardamom essential oils: a combined molecular docking and experimental study

“…According to the review of literature, Escherichia coli, a gram-negative bacterium, is one of the most versatile microorganisms reported in nature, contributes to form biofilm easily on the different surfaces of food industry (Frozi et al 2017). Similarly, Bacillus subtilis is a grampositive soil bacterium that is constantly exposed to a broad range of environmental stresses (Borriss et al 2018) and can respond to stressful conditions by forming biofilm on different surfaces (Romero et al 2010).…”