Biofilm Production Potential of Salmonella Serovars Isolated from Chickens in North West Province, South Africa

Abstract

Bacterial biofilms have recently gained considerable interest in the food production and medical industries due to their ability to resist destruction by disinfectants and other antimicrobials. Biofilms are extracellular polymer matrices that may enhance the survival of pathogens even when exposed to environmental stress. The effect of incubation temperatures (25°C, 37°C, and 40°C) and Salmonella serotype on biofilm-forming potentials was evaluated. Previously typed Salmonella serotypes (55) isolated from the gut of chickens were accessed for biofilms formation using a standard assay. Salmonella Typhimurium ATCC 14028TM and Salmonella Enteritidis ATCC 13076TM (positive controls), Escherichia coli (internal control) and un-inoculated Luria Bertani (LB) broth (negative control) were used. The isolates formed no biofilm (11.86–13.56%), weak (11.86–45.76%), moderate (18.64–20.34%), strong biofilms (23.73–54.24%) across the various temperatures investigated. Serotypes, Salmonella Heidelberg and Salmonella Weltevreden were the strongest biofilm formers at temperatures (25°C, 37°C, and 40°C, respectively). The potential of a large proportion (80%) of Salmonella serotypes to form biofilms increased with increasing incubation temperatures but decreased at 40°C. Findings indicate that average temperature favours biofilm formation by Salmonella serotypes. However, the influence of incubation temperature on biofilm formation was greater when compared to serotype. A positive correlation exists between Salmonella biofilm formed at 25°C, 37°C and 40°C (p ≥ 0.01). The ability of Salmonella species to form biofilms at 25°C and 37°C suggests that these serotypes may present severe challenges to food-processing and hospital facilities.

Molecular detection, typing, and virulence potential of Salmonella Serotypes isolated from poultry feeds

“…Half of the serotypes in our study were able to form biofilm with varied adhesion strengths (Table 3). This result corroborates the results of recent studies that show Salmonella serotypes are capable of producing biofilms with various intensities (Díez-García et al 2012, Akinola et al 2020. The variety of strains can be seen as the reason for the difference in the ability of biofilm formation (Kalai Chelvam et al 2014).…”

“…Biofilm forming bacteria contribute to many microbial infections. The ability of different Salmonella serotypes to produce biofilm has been reported in several studies (Silva et al 2019, Akinola et al 2020. Half of the serotypes in our study were able to form biofilm with varied adhesion strengths (Table 3).…”

Prevalence and Characterization of Salmonella Isolated from Chickens in Anhui, China

“…Similar to our results, 62% of S. Enteritidis and 73.8% of S. Typhimurium isolates from avian sources exhibited the ability to form biofilms, with S. Enteritidis demonstrating a strong capacity for adhesion [ 72 ]. Among Salmonella isolated from chickens in South Africa, the proportion of isolates producing biofilms at different temperatures reached 86.44–88.14%, and S. Heidelberg and S. Weltevreden were the serovars with the highest biofilm-forming capacities [ 73 ]. Another study found that all of the Salmonella serovars were isolated from meat, with 75.86% exhibiting moderate biofilm formation and 24.14% displaying strong biofilm formation.…”

“…Silva et al [ 75 ] believed that S. Gallinarum and S. Minnesota had stronger biofilm production abilities than the S. Enteritidis, S. Typhimurium, and S. Heidelberg serovars. However, the impact of incubation temperature on biofilm formation was found to be more significant than that of the serovar [ 72 , 73 ]. The results of different studies indicated that the differences in biofilm production ability might be more related to the source, region, and characteristics of the isolates themselves.…”

Salmonella Biofilm on Food Contact Surfaces and the Efficacy of Chemical Disinfectants: A Systematic Review

“…In addition, Salmonella spp. has been linked as the causative agent for foodborne illness in many cases in recent years (Akinola et al, 2020), and the formation of biofilm on food contact surfaces certainly contributes to cross-contamination and increases the risk of a foodborne outbreak (Lee et al, 2020). Therefore, many studies were conducted to identify the characteristics of biofilm and the effectiveness of disinfectants on it.…”