A new classification criterion for the biofilm formation index: A study of the biofilm dynamics of pathogenic Vibrio species isolated from seafood and food contact surfaces

Abstract

The bacterial biofilm formation index (BFI) is measured by a microtiter plate assay, and it is typically performed at 72 hr. However, the dynamics of biopolymer formation change during this incubation period. The aims of this study were to follow the biofilm formation dynamics of Vibrio strains isolated from samples of seafood and food contact surfaces (FCS) and to propose a new BFI classification criterion. Samples from seafood (136) and FCS (14) were collected from retail markets in Queretaro, Mexico. The presence of Vibrio spp. was determined, the strains were isolated, and the six major pathogenic species (V. cholerae, V. alginolyticus, V. fluvialis, V. parahaemolyticus, V. vulnificus, V. mimicus) were identified by PCR. The BFI of the isolates was determined by the microtiter plate method. Fifty‐one strains were isolated and identified as V. alginolytivcus (25), V. vulnificus (12), V. cholerae (7), V. parahaemolyticus (6), and V. mimicus (1). A quantitative classification criterion of biofilm formation was proposed based on the following factors: BFI dynamics (no formation, continuous increase, and increase followed by decrease), time of maximum BFI (early: 24 hr; late: 48 to 72 hr), and degree of BFI (none, weak, moderate, and strong). A numerical value was assigned to each factor to correlate the resulting BFI profile with a risk level. Thirteen BFI profiles were observed, having risk level values from 0 to 10. Vibrio alginolyticus, V. cholerae, and V. vulnificus showed the highest BFI profile diversities, which included the riskiest profiles. The proposed BFI criterion describes the dynamics of bacterial biopolymer formation and associates them with the possible risk implications. Practical Application In food processing environments, the presence of bacterial biofilms that could include foodborne pathogens might favor cross‐contamination due to direct contact or biofilm dispersal into food products. The new quantitative classification criterion for biofilm formation considers their production dynamics over time, the biofilm quantity, and the level of biofilm dispersal. These characteristics are represented by a numerical value that reflects the level of risk associated with the presence of a biofilm‐producing strain on a food contact surface.

Biofilms as a microbial hazard in the food industry: A scoping review

“…The production of EPS was found to play a significant role in biofilm formation (Borucki et al, 2003; Wang, Ding, Dong, et al, 2013; Wang, Ding, Wang, et al, 2013; Wang, Ye, Wei, et al, 2013). Lucero‐Mejía et al (2020) developed a biofilm forming index as a criterion for classifying biofilm forming isolates on the basis of bacterial biopolymer development. The high biofilm forming L. monocytogenes isolates were reported to have a high EPS production and thereby more persistent cell adherence (Borucki et al, 2003).…”

“…(Lapierre et al, 2020), Clostridium perfringens (Hu et al, 2018), Escherichia coli (Ramires et al, 2020), Vibrio spp. (Lucero‐Mejía et al, 2020), Bacillus cereus (Kowalska et al, 2020) , Enterococci spp. (Castaño‐Arriba et al, 2020), Campylobacter jejuni (García‐Sánchez et al, 2019) etc., were observed to form the biofilms on food surfaces and associated environment, thereby posing serious food safety concerns.…”

Genomic and Phenotypic Characteristics for Vibrio vulnificus Infections

“…Biofilms are three-dimensional complex matrix structures that might favor cross-contamination of aquatic organisms, such as Vibrio species. 19 Previous studies demonstrated that biofilm formation is important for the ecology, transmission and virulence of VV and V. parahaemolyticus . 20 , 21 The isolates variability could lead to the heterogeneous biofilm formation.…”

Evaluating the effects of zeolitic imidazolate framework and Eremostachys binalodensis extract on Candida albicans and Streptococcus mutans biofilms

“…All assays were repeated in triplicate. Optical density cut‐off (OD c ) (for negative controls) was calculated according to the formula below and the OD/OD c rate was used as an index for biofilm formation (Table 1) [31–33]. $$$$\begin{eqnarray*} O{D}_{c}& =& \left(\textit{ODof}\textit{nega}\textit{tive}\textit{cont}\textit{rolw}\textit{ells}\right)+3\\ & & \times\,\textit{SDofO}{D}_{\textit{avg}}\left(\textit{nega}\textit{tive}\textit{cont}\textit{rolw}\textit{ells}\right) \end{eqnarray*}$$$$where avg denotes the average and SD the standard deviation of the OD of the negative control.…”

“…All assays were repeated in triplicate. Optical density cut-off (OD c ) (for negative controls) was calculated according to the formula below and the OD/OD c rate was used as an index for biofilm formation (Table 1) [31][32][33]. where avg denotes the average and SD the standard deviation of the OD of the negative control.…”