# Evaluation of the Adhesive Potential of Bacteria Isolated from Meat-Related Sources
## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Index** & **Chlororform** & \
\begin{tabular}{c} **Ethyl** \\ **Acetate** \\ \end{tabular} & **Swarming** & **Swimming** &
\begin{tabular}{c} **24 h 20 \({}^{\circ}\)C** \\ **Adhesion** \\ \end{tabular} & **Adhesion** & **Adhesion** & **Adhesion** & **Adhesion** \\ \hline Xylene & 0.73 ** & 0.54 ** & 0.20 & 0.09 & 0.33 ** & 0.37 ** & 0.48 ** & 0.25 \\ Chloroform & & 0.77 ** & \(-\)0.11 & \(-\)0.33 ** & 0.21 & 0.63 ** & 0.68 ** & 0.46 ** \\ Ethyl acetate & & & \(-\)0.07 & \(-\)0.28 * & 0.23 & 0.50 ** & 0.50 ** & 0.50 ** & 0.27 * \\ Swarming & & & & 0.81 ** & 0.23 & 0.14 & 0.02 & 0.14 \\ Swimming & & & & & 0.08 & \(-\)0.05 & \(-\)0.17 & \(-\)0.00 \\
24 h 20 \({}^{\circ}\)C adhesion & & & & & & 0.58 ** & 0.50 ** & 0.47 ** \\
24 h 30 \({}^{\circ}\)C adhesion & & & & & & & 0.80 ** & 0.63 ** \\
72 h 20 \({}^{\circ}\)C adhesion & & & & & & & & 0.61 ** \\ \hline \hline \end{tabular}  
* \({}^{*}p<0.05\); ** \({}^{*}p<0.01\).  
\end{table} 
Table 2: Correlation coefficients between adhesion with cell surface characteristics of the 14 isolates. time had an influence on the biofilm-forming ability. One complete development cycle of biofilm formation includes dispersion as the last step, which promotes the detachment of cells from the mature biofilm [18]. Moreover, this phenomenon results from the starvation of cells in regard to limited perfusion of nutrients and restricted removal of waste [19]. The period during which bacteria showed an impaired adhesion ability in the present study might refer to this development phase. Under 20 \({}^{\circ}\)C, the biofilm formed by the majority of the isolates at 24 h (e.g., _A. salmonicida_ and _Pseudomonas_) grew over time to mature and disperse, leading to a decrease in the amount of biofilm at 72 h. While under 30 \({}^{\circ}\)C, the development of biofilm might be delayed so that at 24 h, the isolates seemed only to colonize, and the biofilm was not formed in a large quantity until 72 h. This partly proved that the lower temperature was preferable for most of the involved bacteria. Nevertheless, attention should be given to the existence of particularity in the biofilm-forming pace of individual strains. Cell adhesion requires contact with the bacterial cell envelope and interacting surface. Motile properties are involved in the meeting of these two objects at the docking stage during the multistep process of adhesion. Two types of motility were investigated in this study: swimming and swarming. The former is a characteristic related to individual movement while the latter shows the movement of a bacterial population. Great variability among genera was observed (Figure 2). Significant distinction existed of a certain single strain (_P. putida_) as well. _E. coli_ and _C. braakii_ showed a superior motility capacity. In the swimming media, they developed a relatively large strain diffusion circle whose diameter was over 75 mm, three times as large as that of the second echelon. _P. putida II_, _R. aquatilis_, and _S. liquefaciens_ exhibited moderate swimming capacity with a diameter of around 20 mm. Less disparity was found in the results of the swarming assay. The five strains mentioned above also possessed a strong swarming ability but were much more reserved compared to their swimming performances. This finding suggested that the fluidity of the medium could possibly influence the diffusion of the microorganisms, a flowing state might favor the cross-contamination in food processing as subsequent biofilm development for instance, whereas no remarkable differences between the two motility-related properties appeared in _P. fluorescens_, _A. veronii_, and _P. putida I_. Both swimming and swarming motility are flagella  
Figure 1: Biofilm formation by 14 selected isolates on 96-well polystyrene microplates under 20 or 30 \({}^{\circ}\)C for 24 h (**a**) and 72 h (**b**). Error bars represent standard deviations of the mean (\(n=5\)). Images of the stained microplates of _A. salmonicida_ I, _C. braakii_ and _L.