Biofilm Forming Ability Of Salmonella Enteritidis In Vitro

Abstract

Salmonella enterica serotype Enteritidis is an important alimentary pathogen that recently gained special attention due to the ability of a large number of strains to form biofi lms. Qualitative testing of biofi lm forming ability was performed by observing the morphotype of the colonies on Congo Red agar and by conducting the pellicle test, while quantitative testing was carried out by Cristal violet assay on microtiter plates. A total of 14 isolates of S.Enteritidis were tested for biofi lm forming ability, while Salmonella Enteritidis ATTC 13076 was used as the reference strain. Based on the morphotype of colonies cultivated on Congo Red agar at 25°C incubation temperature, among tested isolates three morphotypes were detected -red, dry and rough (rdar), brown, dry and rough (bdar) and smooth and white (saw). Half of the tested isolates demonstrated rdar morphotype. All isolates that showed a specifi c morphotype at this incubation temperature also formed the corresponding type of pellicle at the air-liquid interface. Additionally, comparing OD (optical density) values obtained by crystal violet test between groups of isolates that represent one of the three detected morphotypes (rdar, bdar and saw), statistically signifi cant differences were detected. Based on OD values obtained by crystal violet test at both applied incubation temperatures, isolates were classifi ed into three categories, regarding their ability to form biofi lms: strong, moderate and weak biofi lm producers. By comparing the amounts of the biofi lms formed after 48h at 25°C and 37°C, statistically signifi cant differences were noted (P<0.05). In this research we presented micrographs and a reconstruction of threedimensional projections of biofi lm developing phases of rdar morphotype isolates, which were obtained using confocal laser scanning microscopy.

Salmonella enterica Serovar Minnesota Biofilms, Susceptibility to Biocides, and Molecular Characterization

“…Regarding the biofilm formation intensity, the same behavior was identified at temperatures of 25 and 36 °C ; these findings contradicts the literature, which states that temperatures below the optimal growth and close to that of the environment intensify the biomass production in Salmonella biofilms [29]. According to Čabarkapa et al [30], factors involved in biofilm production have different responses depending on bacterial strain and according to the temperature of incubation.…”

Molecular Characterization and Survive Abilities of Salmonella Heidelberg Strains of Poultry Origin in Brazil

“…The influence of temperature on the establishment of biofilms is described as a serovar-and strain-dependent characteristic. Although thermal stress at low temperatures is an important trigger for the production of biofilms (Stepanović et al, 2003;Ivana et al, 2015;Piras et al, 2015), the test at 4 • C may have made bacterial multiplication infeasible due to its proximity to the minimum growth temperature (Matches and Liston, 1968). The inclusion of CJ promoted a significant reinforcement in bacterial biomass, increasing on average 0.2114 the BFI when compared to the value of the non-supplemented samples, except at 4 • C (Table 4).…”

Biofilm Formation and Extended Spectrum Beta Lactamase (ESBL) Production of Bacterial Strains Isolated From Sewage Water

“…100 µL from five and eight-fold dilutions were spread on congo red agar. And plates were incubated for 24 h at 37°C (Mathur et al, 2006;Ivana et al, 2015;Lima et al, 2017). After incubation, the colors of colonies on plates were observed.…”

“…The plates were incubated for 168 h at 37°C. Following the incubation period, colony morphology of biofilms was stated as rdar (red, dry and rough), bdar (brown, dry and rough), pdar (pink, dry and rough) and saw (smooth and wet) (Akyıldız, 2015;Ivana et al, 2015).The experiment was separately performed in triplicate. Tube adherence method (TM): Biofilm production at the liquid medium was analyzed by the tube adherence method.…”