# Evaluation of the Adhesive Potential of Bacteria Isolated from Meat-Related Sources
## 3 Results and Discussion
curvatus_ are shown as representatives. dependent. It was reported that flagellar motility played an essential role in assisting microorganisms to reach proximate to the surface at the early beginning of adhesion [20]. The wide range of performances among strains in the present study might mainly result from the diversity of flagellar characteristics, but also other infectors such as biosurfactant production and QS signaling [21; 22]. However, all bacteria with remarkable motile capacity were not strong in forming biofilms, taking _E. coli_ and _C. braakli_ as examples. Furthermore, no correlation was determined in this study between motility and biofilm formation from a general view (Table 2). This finding suggested that the role of flagella-based motility might not be of critical importance to the attachment of microorganisms and it might alter the adhesion process of different bacteria. In spite of the transition from planktonic mode to biofilm growth mode promoted by motility, it might keep cells away from the surface through active movements in the meantime. Moreover, many other factors (e.g., surface interactions) exist contributing to the adhesion process. Nevertheless, the function of flagella cannot be ignored. It was found by video microscopy that the flagellum was required for rapid attachment of _Vibrio cholerae_ to a surface, and flagellar mutant was defective in initial attachment to abiotic surfaces [23]. ([PERSON] et al., 2001). In addition, if focusing alone on the tested _Lactobacillus_ spp., all three isolates had the weakest motility capacity, which is reasonable because lactobacillus rarely carry flagella and move with them. Their consistently poor abilities displayed in both adhesion and motility assays provide a hint to the intrinsic connection between these two features. Surface characteristics such as hydrophobicity are also estimated to be able to influence the outcome of primary adhesion. Bacterial surfaces with hydrophilic properties were reported to be beneficial for electroactive biofilm formation [24]. These factors are usually species and strain-dependent. The differences in affinity may be due to the composition and content of different lipopolysaccharidesaccharides, capsular material, or appendages on the cell surface. In our study, xylene, which is an apolar solvent, was used to determine cell surface hydrophobicity, and the expression of cell affinity to this solvent varied significantly among strains evaluated (Table 1). High affinity to xylene was detected in _Pseudomonas_ and _Aeromonas_ genera (with exception of isolates _P. fluorescens_ and _A. salmonicida_ I), represent  
Figure 2: Motility ability evaluated by diffusion circle diameter (mm) of the 14 individual strains. Error bars represent standard deviations of the mean (\(n=6\)). Colony patterns formed by _C. braakli_, _P. putida_ II and _L. curvatu_ were shown as representatives. ing an advantageous hydrophobic ability, while the _Lactobacillus_ strains showed a strong hydrophilic property, with an affinity value to xylene under 20%, and even lower than 5% in _L. curvatus_. Furthermore, _S. liquefaciens_ and _C. braakii_ were another two competitors in hydrophobicity. The existing distinctions in this assay might be a consequence of varied envelope molecules, especially proteins and polysaccharides. Some evidence showed that the attendance of protein was likely to promote hydrophobic behavior whereas the participation of polysaccharides may result in better hydrophilic capacity [25; 26]. General correlation was evident between cell surface hydrophobicity and biofilm formation (Table 2). Bacteria that possessed high hydrophobic surfaces such as _Pseudomonas_ and _Aeromonas_ attached readily to the model surface, while _Lactobacillus_ strains that were more hydrophilic displayed poor biofilm-forming ability. It is in line with the finding of an investigation into surface characteristics of 50 _Lactococcus lactis_ strains that more hydrophobic isolates were found to adhere more to polystyrene [27].