Staphylococcus pseudintermedius infections present a serious challenge because of the emergence of resistance to numerous conventional antibiotics. Antimicrobial peptides are novel alternatives to traditional antibiotics due to their unique mechanism of action. In this study, we investigated the antibacterial activity of 12 short synthetic peptides against two clinical isolates of S. pseudintermedius isolated from two dog cases with ophthalmic lesions. In addition, the ability of the peptides to disrupt the established biofilm of these two S. pseudintermedius isolates was investigated. RRIKA and 5RHH showed good antimicrobial activity with MICs 2 and 4 µg/ml, respectively. IK8aIID and Indolicidin showed antimicrobial activity with MICs 8 and 16 µg/ml, respectively. Indolicidin, 5RHH and IK8aIID showed a significant biofilm mass % reduction up to 90%.  Taken together, these results support the potential use of antimicrobial peptides for the treatment of S. pseudintermedius infections.

Staphylococcus aureus is the most bacteria that have ability to form a biofilm and secret different types of enterotoxins that cause food poisoning in humans. Biofilms is a community of microorganisms encased in a matrix of extracellular polysaccharide (slime), called polysaccharide intercellular adhesion (PIA). They have related to a diversity of chronic and persistent infections. This study aims to detect the ability of S. aureus isolated from ice cream to form biofilm by Congo red agar (CRA), microliter plate, and PCR and the ability of S. aureus to produce enterotoxins by PCR. 15 S. aureus isolates were grown on CRA and microtiter plate method then subjected for detection of icaA and icaD genes by PCR and for the presence of enterotoxins genes (sea, seb, sec, sed, and see) which are responsible for S. aureus biofilm formation and Staphylococcus food poisoning. 73.3% of the isolates were biofilm producers on Congo red agar, 60% of the isolates were positive for biofilm production using microtiter plate method and by PCR technique, all the isolates 100% had icaD gene and 86.6% had icaA gene. The enterotoxin seb gene was detected in 5 (33.3%) S. aureus isolates, the enterotoxin see gene was detected in 4 (26.6%) S. aureus isolates while sea, seb and sed gens were not detected in any S. aureus isolates. In conclusion all aureus isolates were positive for icaD gene and some of S. aureus isolates were positive for icaA gene which are responsible for biofilm formation and some S. aureus isolates were positive for enterotoxin B and enterotoxin E, which responsible for food intoxication so the ice-cream considered a potential source for food intoxication and persistent infection caused by S. aureus.

Staphylococcosis infections are common in poultry worldwide because of the causative bacteria resisting a wide range of commonly used antibiotics. The formation of biofilm is the hallmark characteristic of staph infection. Biofilms constitute reservoir of pathogens and are associated with resistance to antimicrobial agent and chronic infections. In this study 90 multidrug resistant staphylococcus strains (61 coagulase- negative staphylococcus (CNS) and 29 S. aureus) were screened by tissue culture plate method for biofilm formation and presence of mecA, icaA, and icaD genes by PCR technique. 38 (42.2%) isolates were strongly positive for biofilm production, 49 (54.4%) were moderate biofilm producers and 3 (3.4%) were weak or negative for biofilm formation. All biofilm producing strains were positive for icaA and icaD genes, and all biofilm negative strains were negative for icaA gene. Biofilm production was higher in methicillin resistant strains as compared to the methicillin sensitive strains of Staphylococcus species. From this study attention should be given in treatment of staphylococcus because Staphylococci isolated showed a high extent of biofilm production. All biofilm producing Staphylococci are positive for icaA and icaD genes, which indicates the important role of ica genes as virulence markers in staphylococcal infections.