This study was carried out on a total of 550 lactating animals; 310 and 240 cows and buffaloes, respectively which were examined for signs of clinical mastitis (swelling, hotness, redness, and apparent milk change) from different dairy farms and veterinary units located at El-Fayoum Governorate during the period from May 2017 to November 2017. Clinical examination proved that out of these animals, a total of 126 animals (87 cattle and 39 buffaloes) were found with clinical mastitis. Streptococcus species were recovered from 73 animals including; 29(39.7%) and 44(60.0%) cows and buffaloes, respectively. Furthermore, out of the 73 Streptococci isolates recovered from cows and buffaloes; there were 10(13.7%) and 15(20.5%) S. agalactiae, 5(6.8%) and 10(23.7%) S. dysgalactiae, 8 (10.6%) and 7 (13.7%) S. uberis, 3(4.1%) and 10(13.7 %) E. fecalis and 3(4.1%) and 2(2.7%) S. lactarius, respectively. Anti-microbial susceptibility testing showed that the highest resistance was recorded against penicillin, gentamicin, streptomycin, and doxycycline (100%). Conversely, the highest sensitivity was recorded against ceftriaxone, ciprofloxacin, and sulfamethoxazole-trimethoprim (100%). Biofilm formation capacity was phenotypically assessed on YESCA CR agar medium and showed that all examined S. agalactiae and S. dysgalactiae were strong biofilm producers, meanwhile, 78%, 50%, and 75% of S. uberis, S. lactarius, and E. fecalis were biofilm positive isolates respectively. Application of PCR technique revealed that enterotoxins producing genes; sed, seb were found in 20% and 80% of isolates, in order. Biofilm-associated genes; fnbA and icaA genes were detected in 90% and 70%, respectively. Resistance genes; mecA and blaZ, genes were possessed in 90% and 70% of isolates, respectively.

This study aimed to characterize the different Staphylococci recovered from mastitic cows and buffaloes. A total of 126 mastitis milk samples were aseptically collected from clinically mastitic animals including 87 cows and 39 buffaloes. Bacteriological examination and biochemical identification using VITEK-2-compact-SYSTEM revealed that a total of 94 Staphylococcus isolates (74.6%) were recovered; 56 isolates (59.6%) and 38 isolates (40%) from cows and buffaloes, respectively. S. aureus was the most predominant isolate (n=26; 15 from cows and 11 from buffaloes) with a percentage of 27.7%. Moreover, 68 coagulase-negative staphylococci (CNS) isolates (72.3%) were identified of which; 21 S. epidermidis (22.3%); all isolates were from cattle, followed by 18 S. lentus (19.1%); 8 and 10 from cows and buffaloes, respectively, 17 S. simulans (18%); 6 and 11 isolates, respectively, and finally 12 S. hominis (12.9%); 5 and 7 isolates, respectively. Antimicrobial susceptibility testing showed that all isolates were sensitive to ceftriaxone, ciprofloxacin, ofloxacin and sulfamethoxazole-trimethoprim. On the contrary, all isolates were resistant to penicillin and streptomycin. Multidrug resistance (MDR) was detected in 21 (22.3%) Staphylococci isolates. Biofilm formation capacity was phenotypically assessed on YESCA CR agar medium and showed that all Staphylococci isolates were curli-producing. Application of PCR technique revealed that sed, seb genes were the most prevalent genes in all isolates, followed by fnbA gene which was detected in 80% of the isolates, and then mecA, blaZ, and icaA with percentages of 60%, 40%, and 40%, respectively.

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.

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.

In 2015 in the European Union member states listeriosis caused 270 deaths. Food is the route of transmission in 99% of all human infection cases. Several studies from different countries have shown that the presence of Listeria monocytogenes in food can be as high as 58.3%. One of the most important ways to protect food from these microorganisms is to prevent the spread of the bacteria at processing plants at different stages of food production chain. The ability of L. monocytogenes to survive in extreme conditions and to form biofilms on various surfaces is a significant challenge for food safety. Removal of these bacteria from niches in processing plants is difficult and requires the use of sanitisers and precise equipment cleaning. The presence of L. monocytogenes in processing environment at slaughterhouses, deli meat factories or in retail may be a reason of cross-contamination. Proper hygienic systems applied by workers in food preparing places and knowledge about different routes of spreading of these bacteria may effectively decrease the risk of food contamination. Standardised legal regulations and control of meat product manufacture should be a fundamental way to protect food from L. monocytogenes contamination.

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.

Streptococcosis is a zoonotic bacterial disease in tilapia and other fresh that creates economic losses, caused mainly by Streptococcus agalactiae and Streptococcus iniae. The hazard of the disease is that it may present apparently healthy as well as its presence in culture water. So, this work aimed to detect streptococci in Nile tilapia farms located in Assiut and Minia Governorates, Egypt. Streptococcus agalactiae (42 isolates) and Streptococcus iniae (59 isolates) were identified. Two Streptococcus agalactiae isolates were molecularly confirmed and exhibited resistance to most antibiotics and a multiple antibiotic resistant index of 0.9-1. The identified isolates could not form biofilm. Identification of these hemolytic, resistant Streptococcus poses a potential hazard for human health; hence, alternative antimicrobials should be searched against infections caused by these bacteria.

Pseudomonas aeruginosa (P. aeruginosa) is a psychotropic pathogenic bacterium that is considered one of the most common spoilage microorganisms related to seafood’s consumption. P. aeruginosa is widely distributed in nature and isolated from soil, plants, animals, and water. Because of its high resistance to a wide range of antibiotics, P. aeruginosa is more dangerous than other spoilage bacteria. It possesses a diverse set of virulence factors capable of causing severe and aggressive infections in humans and animals. Antibiotic resistance genes are easily transmitted to humans via contaminated seafood, resulting in a serious antibiotic resistance.  The ability of P. aeruginosa to form a biofilm maintains its environmental survival and allows its quick adaptation to harsh environments. Therefore, for the benefit of customers and public health globally, the safety and bacteriological quality of commercially processed fish and its products are crucial.