To experimentally evaluate chitosan nanoparticles (ChNPs) as alternative to antibiotics on controlling biofilm forming E. coli isolated from omphalitis cases. A total of 100 yolk sac samples were collected from diseased and dead chicks (1-10 days old) suffered from omphalitis. Yolk sacs were collected from different farms at Assiut city, Egypt. Out of 100 collected samples, a total of 36 E. coli isolates were isolated with a prevalence rate of 36%, these isolates belonged to 11 different serotypes, which showed biofilm production that confirmed experimentally by two methods (crystal violet assay and congo red agar), all biofilm producers of E. coli serotypes showed resistance to one or more antibiotics by disc diffusion method. Chitosan nanoparticles exhibited superior antimicrobial activity against all the 11 E. coli strains in comparison with used antibiotics, the maximum inhibition zone diameter recorded was 32 mm at concentration of 0.1% (ChNPs) and the lowest was 11 mm by Agar well diffusion assay. In Ovo colonization with 0.1 % chitosan nanoparticles at the 18th day of incubation through amniotic route had positive impacts on bacterial count of recovered E. coli isolates (2.9×105 CFU) without any adverse effect on hatchability.

Contamination by Staphylococcus aureus of food produced from animal sources may have diverse and multifactorial causes that depend on geographical distribution. The goal of this study was to isolate and characterise S. aureus strains from contaminated fermented pork sausage, which is a local food of northeastern Thailand. S. aureus strains were isolated from local pork sausage, and the presence of classical enterotoxins was determined by PCR and reversed passive latex agglutination. These results were compared with strains derived from hospitalised patients and healthy carriers. Additionally, production of extracellular enzymes and haemolysin, biofilm formation, and antibiotic susceptibility were assessed. S. aureus was identified in 36 sausage isolates (60%). The strains positive for staphylococcal enterotoxin A were more frequently found in isolates from sausage and healthy carriers than in those from patients. All tested S. aureus strains were positive for DNase, lipase, proteinase, haemolysin, and biofilm formation; notably, strains isolated from food and healthy carriers displayed similar values. Most isolates were resistant to penicillin and ampicillin, while none were to methicillin. Thai fermented pork sausages are associated with a high risk of staphylococcal food poisoning, which may be linked to contamination caused by carriers. Dissemination of knowledge regarding best practices in sanitation and hygiene is important in local communities.