This study was conducted on 100 diseased Nile tilapia (O. niloticus) fish of various sizes collected from different fish markets in Kaliobia Governorate to estimate the prevalence of Pseudomonas infection and detection of some virulence genes in the isolated P. aeruginosa strains. The results of bacteriological examination revealed that the prevalence of Pseudomonas septicemia with Pseudomonas species isolation was 17.0% (17 \ 100 examined fish). These cases were attributed to P. anguilliseptica; P. aeruginosa and P. fluorescens (14/43.7%; 12/37.5% and 6/18.8%), respectively. In addition, 32 Pseudomonas species were isolated, 11from liver samples (34.4%); 10 from kidney samples (31.2%); 6 from gill samples (18.8%) and 5 from skin samples (15.6%). Moreover, 14 P. anguilliseptica were isolated with an incidence of 35.7%, 28.6%, 21.4% and 14.3% followed by 12 P. aeruginosa 33.3%, 25%,16.7% and 25% respectively; 6 P. fluorescens 33.3%; 50.0%,16.7% and 0.0% from the liver, kidney, gill and skin samples respectively. The in-vitro antimicrobial sensitivity test showed that the isolated Pseudomonas strains were sensitive to gentamycin; enrofloxacin; norfloxacin; ciprofloxacin and florphenicol. Meanwhile; they were intermediate sensitive for doxycycline; sulfa-trimethoprim; oxytetracycline; nalidixic acid and streptomycin. In contrast, they were resistant for cefotaxime; erythromycin; amoxicillin; methicillin; oxacillin and ampicillin. Moreover, the PCR results revealed that, opr L and exo S virulence genes were detected in all six studied strains (100.0%). Meanwhile, phz M virulence gene was detected in 5 out of 6 studied strains (83.3%) and tox A virulence gene was detected in 4 out of 6 studied strains (66.7%) i.e., all studied strains were Ps. aeruginosa and all of them were virulent strains.

A total of 200 random samples of raw milk, Fita cheese, Kariesh cheese and ice cream (50 samples each) were collected from small retails and different supermarkets in El-Kaliobia Governorate to estimate the prevalence of Listeria species in such products with special interest to L. monocytogenes. The bacteriological examination of the samples resulted; 13(6.5%) isolates of Listeria species were recovered from 200 samples, includes 10 L. monocytogenes (5.0%) and 3 L. grayi (1.5%). Moreover, the other 4 species (L. ivanovii; L. innocua; L. seeligeri and L. welshimeri) were not isolated from all samples (Listeria strains). The in-vitro antimicrobial sensitivity test showed that the isolated L. monocytogenes were sensitive to amoxicillin; gentamycin; enrofloxacin; kanamycin and ampicillin. While they were resistant to Nalidixic acid, streptomycin and tetracycline. The results of virulence tests for isolated Listeria strains appeared that all of L. monocytogenes strains were virulent strains as all of them were positive to CAMP test; showed narrow zone of β-hemolysis on sheep blood agar and were positive for Anton's test. Meanwhile, L. grayi strains were non-virulent, as none of them could produce hemolysin (CAMP test negative) and negative for Anton's test. The PCR results for L. monocytogenes showed that all genes (16S rRNA; inlA; inlB; hlyA and prfA) were detected in five studied strains (100.0%) i.e., all studied strains were L. monocytogenes and all of them were virulent strains.

A total of 125 random samples of fresh chicken, meat beef and beef meat products viz: minced meat, beef burger and sausage (25 for each), were collected from different shops in Benha city. The bacteriological examination of the samples indicated the isolation of food-borne pathogens from 79 positive samples (63.2%) where, 113 isolates of food-borne pathogens were recovered from these samples, includes E. coli (46.9%), Salmonellae (17.7%) and S. aureus (35.4%). They were isolated from minced meat samples (28.3%) followed by sausage, chicken meat, beef meat and beef burger samples with an incidence of 21.2%, 19.4%, 18.6%, and12.4%, respectively. E. coli strains (53) were isolated mostly from minced meat samples (13 = 24.5%) followed by sausage (12 = 22.6%), beef meat (11 = o 20.8%), chicken meat (10 = 18.9%) and beef burger samples (7 = of 13.2%). Different serotypes of E. coli (O55:H7, O78, O111:H4, O26:H11, O119:H4, O125:H18 beside 10 untyped strains) were recorded. All E. coli strains are sensitive to enrofloxacin, cefotaxime, gentamycin and norfloxacin. Salmonella strains (20) were isolated from minced meat (7 = 35%), sausage and chicken meat (4 = 20.0% for each one), beef meat (3 = 15%) and beef burger samples (2=10%).Three serotypes of Salmonellae were isolated as S. Typhimurium (10 = 50%), S. Enteritidis (8 = 40%) and S. Typhi (2 = 10%) were recorded. The isolated Salmonella strains were highly sensitive to gentamycin, norfloxacin, enrofloxacin, ciprofloxacin and cefotaxime. S. aureus strains (40) were isolated from minced meat (12 = 30%), sausage and chicken meat (8 = 20% for each one), beef meat (7 = 17.5%) and beef burger (5 = 12.5%). All isolated strains were coagulase positive S. aureus. 6 strains out of 10 randomly examined S. aureus strains (60.0%) were enterotoxigenic and classified according to type of toxin into (3A, 1B, 1C, 1A&C). Moreover, the isolated S. aureus was highly sensitive to norfloxacin, enrofloxacin, gentamycin and ciprofloxacin.

The study was performed on 225 chicken (72 diseased and 153 freshly dead ones) from different 45 commercial broiler farms (1-30 days old) at Dakahlia Governorate for mycotic infection. Samples were taken from these chickens (lung; air sac; crop; liver and brain from each chicken) after clinical and postmortem examination for mycological examination. The results revealed that, fungi were isolated from 503 positive samples (44.7%); represented as 119 positive samples (10.6%) from diseased chickens and 384 positive samples (34.1 %) from freshly dead ones.651 fungal isolates (moulds and yeasts) were isolated from 1125 samples, where 219(33.6%) were isolated from lung samples followed by 199(30.6%); 119(18.3%); 91(14.0%) and 23(3.5%) from air sac, liver, crop and brain samples respectively. Moreover, A. fumigatus was the most isolated one 141(21.7%) followed by A. flavus 126(19.4%); A. niger 111(17.1%); Rhizopus spp. 67(10.3%); C. albicans 58(8.9%); Mucor spp. 42(6.5%); Penicillium spp. 32(4.9%); A. terreus 20(3.1%); Fusarium spp.19 (2.9%); C. krusei 13(2.0%); C. tropicalis 9(1.4%); A. candidus 9(1.4%) and finally A. ochraceus 4(0.6%). PCR using fungus-specific universal primer pairs (ITS1 and ITS4) was used for identification and genotypic characters of Aspergillus species (A. fumigatus; A. flavus and A. niger).They were able to successfully amplify the ITS1-5.8S rDNA region of all tested Aspergillus isolates, providing a single PCR product of about 600 bp for all tested isolates PCR using fungus-specific universal primer pairs (ITS and RPS) was used for identification and genotypic characters of C. providing a single PCR product of about 109 bp .Sequence of the internal transcribed spacer 1 reigon (ITS-1) of isolated A. flavus Gene Bank accession number for studied nucleotide sequence (Bankit 1867303) is KM 983253. The sequences obtained for ITS-1 region were more than 98% identical to the corresponding GenBank sequences (accession no. DQ467968.1; KC994648.1; LN482516.1 and KP689246.1). Sequence of the internal transcribed spacer 1 region (ITS-1) of isolated C. albicans. Gene Bank accession number for studied nucleotide sequence (Bankit 1867955) is KM 983254. The sequences obtained for ITS-1 region obtained were more than 95% identical to the corresponding GenBank (accession no. M87288.1; gb|S71769.1|S71769; emb (AL033396.1) and AP006852.1).

The current study was conducted on 210 random samples of meat products (beef burger, kofta, luncheon, minced meat, sausage) and diarrheic human stool of patients suffering from vomiting and diarrhea (35 for each). The meat products were collected from different shops and hospitals at Kaliobia Governorate, Egypt, for detection of B. cereus strains, and their phenotypic characterization as well as antibiotic resistant genes. Bacteriological examination of the collected samples indicated the identification of 51 (24.3%) isolates of B. cereus from 210 samples as 11 (31.4%) from kofta 13 (37.1%) from minced meat, 9 (25.7%) from sausage, 7 (20.0%) from beef burger, 6 (17.1%) from luncheon samples, and 5 (14.3%) from human stool specimens. Most of 51 isolated B. cereus strains had the ability for biofilm production. The antibiotic sensitivity profiles revealed that the isolated B. cereus was highly resistant for Penicillin-G followed by methicillin, ampicillin, oxytetracycline, sulfatrimethoprim and cefotaxime. Meanwhile, they were highly sensitive to gentamycin and norfloxacin followed by ciprofloxacin, meropenem and florphenicol. Further, PCR declared that bla, tetA and erm genes were amplified in 9, 7, 6 out of 10 studied B. cereus isolates giving products of 680 bp, 502 bp, and 645 bp, respectively. Therefore, one can conclude that B. cereus, especially antibiotic resistances ones, is meat-borne pathogens of public health importance and they may be the causative agents in patients suffering from vomiting and diarrhea.