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.

Campylobacter fetus subsp. fetus is an opportunistic human pathogen that is frequently identified as a cause of intestinal infections as well as bloodstream infections. This bacterium is well known to cause spontaneous abortions in sheep and cows. The strain reported in this study was isolated from a preputial wash sample from a bull in South Africa.

Campylobacter fetus subspecies are mostly characterized by reproductions problems in cattle and sheep. This study aimed to study the genetic profile and assess the genes mechanism of resistance and their virulence factors using genome sequence analysis. A total of 59 confirmed Campylobacter fetus subspecies based on molecular assays and DNA sequencing were subjected to antimicrobial susceptibility test against 14 antibiotic agents representing the five classes of antibiotics using the disc diffusion method. In addition, sequencing the genome of all strains induced complete resistance against all tested antibiotics. The results of the antimicrobial test indicated that 54.4% had a resistance profile, 26.3% were intermediate, while 19.3% were observed to be susceptible. The Whole Genome Sequencing (WGS) result revealed the presence of different genes, such as Broad-specificity multidrug efflux pump and 16S rRNA (guanine527-N7)-methyltransferase (gidB), efflux pump conferring antibiotic resistance (MacA and MacB), protein-altering cell wall charge conferring antibiotic resistance (PgsA), which have never been reported in Campylobacter fetus subspecies. The WGS also revealed the presence of genes that involved in colonization, adhesion, motility, and invasion, such as type IV secretion system protein (VirD4), S-Layer, cytolethal distending toxin (A, B, and C), Campylobacter invasion antigen (CiaB), and fic domain protein (fic) were among important CDS. The presence of these uncommon genes explains the resistance of Campylobacter fetus subspecies against different tested antibiotics. The results of this study can be used to implement molecular surveillance of Campylobacter fetus subspecies and conduct further studies on the resistance mechanism in these subspecies.

Campylobacter fetus subsp. venerealis is the causative agent of bovine genital campylobacteriosis, which is mostly characterized by reproduction problems. The strain reported in this study was isolated from bull sheath wash in South Africa.