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.

Microbial biofilm is one of the most serious problems facing poultry farms all over the world and especially in Egypt. Salmonella, E. coli and S. aureus were the highest implicated bacteria in biofilm formation in poultry farms. Consequently, 440 samples were collected from 8- broiler and 8-layer farms at El- Sharkia Province, Egypt, during the period from (July 2021till August 2022). The objective of the study was to evaluate biofilm development capacity of the tested bacterial species by the microtiter plate (MTP) assay. Also, the efficacy of five disinfectants commonly used in poultry farms (Sodium hypochlorite, hydrogen peroxide, Virkon S, glutaraldehyde and copper sulphate) with different concentrations (1, 2 and 5%) and different contact times (10, 60 and 120 m) on reducing the biofilms produced by S. Enteritidis, E. coli O78 and S. aureus was estimated. Results showed that out of 440 collected samples, 17 (3.8%), 200(45.5%) and 66 (15%) strains were identified as Salmonella, E. coli and S. aureus, respectively. 88.2%, 92% and 87.8% of the isolates of Salmonella, E. coli and S. aureus were biofilm producers. The most effective disinfectant was sodium hypochlorite which eliminated the biofilms of S. Enteritidis and E. coliO78 when used at concentration 5% for 120m while 5% for 60 m against S. aureus biofilm. Additionally, hydrogen peroxide showed great efficiency and complete removal of biofilm of S. Enteritidis when used at concentration 2% for 120m and 5%f or 120 m against S. aureus biofilm, meanwhile removed 91% of E. coli O78 biofilm when used at concentration of 5% for 120 m. However, Copper Sulphate was insufficient disinfectant to be used against the biofilms. It can be concluded that the anti-biofilm efficiency of the disinfectants increases with the increase concentration and contact time with biofilms especially when using oxidizing disinfectants (hypochlorite and peroxides).

Staphylococcus aureus is a major pathogen that affects both people and animals. Staphylococcus aureus causes food poisoning in addition to invasive diseases as arthritis and septicemia. This study was done on 70 chicken samples obtained from 7 different farms of chickens with symptoms of arthritis in Kafr El-sheikh government, Egypt. In this study out of 70 samples of chickens from different farms, 37 (52.8%) samples were recognized as coagulase-positive staphylococci (CoPS) and 33 (47.1%) were recognized as coagulase-negative staphylococci (CoNS). By using the microtitre plate method, seven out of 37 (18.9%) CoPS were positive for biofilm production with variable degrees. The pattern of antibacterial sensitivity of 7 Staphylococcus aureus isolates against 12 commercially available antibiotic discs showed 100 % resistance to oxytetracycline then Amoxicillin (71.43%), Erythromycin (57.14%), Norfloxacin (14.29%), Tetracycline (42.86), Sulphamethoxazole (42.86%), Gentamicin (42.86%), Ampicillin (42.86%), kanamycin (28.57), cephatotin (28.57), doxycycline (0%) and the least was observed with chloramphenicol (0%). seven of positive S. aureus isolates were introduced in order to identify the staphylococcal enterotoxin genes, SEA, SEB, SEC, SED, and SEE and integron by PCR test Which 4 out of 7 isolates (57.1 %) were positive for SEB and SED only while were other isolate were negative for all SE gene. Class 1 integron cassettes were detected in 6 isolates from 7 (85.7%) of tested isolates. In conclusion, this is the first study to report the detection and identification of enterotoxin and class 1 integron in S. aureus isolated from poultry meat of chicken that suffered from arthritis.

Bacillus cereus (B. cereus) is a Gram-positive, spore-forming, and facultative anaerobic bacterium that is widely distributed in the environment. Commonly, B. cereus is a soil occupant and is generally isolated from food and food products. It is a human pathogen that causes two variant types of gastrointestinal diseases: diarrheal and emetic. Diseases caused by multidrug-resistant (MDR) bacteria are difficult to be treated. In addition, group of B. cereus has several virulence factors, which play their roles in pathogenesis, infectivity and its capability to form biofilms. B. cereus biofilm is grown on medical devices either abiotic or biotic surfaces. This biofilm avoids the bacteria from the effect of antibiotics and host immune system leading to chronic infections, persistence and mortalities. Thus, it is necessary to explore new antiquorum and antibiofilm agents better than the conventional therapy to eliminate the biofilm that reflect on controlling B. cereus infections. The present review will discuss B. cereus virulence attributes, antibiotic resistance profiles, and their ability to produce biofilm as well as its molecular regulation. The application of the antiquorum and antibiofilm approaches for infection control will be illustrated as well. Finally, we will spot the light on their consequence in food industry loses and human health risk.