Edible films and essential oil (EO) systems have the potency to enhance the microbial quality and shelf life of food. This investigation aimed to evaluate the efficacy of chitosan films including essential oils against spoilage bacteria and foodborne pathogens associated with meat. Antimicrobial activity (in vitro and in vivo) of chitosan films (CH) incorporated with oregano oil (OO) and thyme oil (TO) at 0.5 and 1% was done against spoilage bacteria and foodborne pathogens, compared to the control sample and CH alone. Preliminary experiments (in vitro) showed that the 1% OO and TO were more active against Staphylococcus aureus compared to Escherichia coli O157:H7 and Salmonella Typhimurium. In in vivo studies, CH containing OO and TO effectively inhibited the three foodborne pathogens and spoilage bacteria linked with packed beef meat which was kept at 4 °C/30 days compared to the control. The total phenolic content of the EOs was 201.52 mg GAE L⁻¹ in thyme and 187.64 mg GAE L⁻¹ in oregano. The antioxidant activity of thyme oil was higher than oregano oil. The results demonstrated that the shelf life of meat including CH with EOs was prolonged ~10 days compared to CH alone. Additionally, CH-OO and CH-TO have improved the sensory acceptability until 25 days, compared to the control. Results revealed that edible films made of chitosan and containing EOs improved the quality parameters and safety attributes of refrigerated or fresh meat.

This study aimed to investigate the prevalence and antimicrobial resistance of enterococci- and ESBL-producing E. coli isolated from milk of bovine mastitis cases in Egypt. Fifty milk samples of dairy animals were collected from localities in the Nile Delta region of Egypt. Isolates were identified using MALDI-TOF MS, and antibiotic susceptibility testing was performed by the broth microdilution method. PCR amplifications were carried out, targeting resistance-associated genes. Seventeen Enterococcus isolates and eight coliform isolates could be cultivated. Vancomycin resistance rate was high in Ent. faecalis. The VITEK 2 system confirmed all E. coli isolates as ESBL-producing. All Ent. faecalis isolates harbored erm(B), tetL and aac-aphD genes. The vanA gene was detected in Ent. faecalis isolate, vanB was found in other Enterococcus, while one isolate of E. casseliflavus exhibited the vanA gene. E. coli isolates exhibited high prevalence of erm(B) and tetL. E. coli isolates were analyzed by DNA microarray analysis. Four isolates were determined by O-serotyping as O8 (n = 1), O86 (n = 2) and O157 (n = 1). H-serotyping resulted in H11, H12, H21 (two isolates each) and one was of H16 type. Different virulence-associated genes were detected in E. coli isolates including lpfA, astA, celB, cmahemL, intI1 and intI2, and the iroN gene was identified by DNA microarray analysis.

The aim of this study was to characterize staphylococci and streptococci in milk from Egyptian bovides. In total, 50 milk samples were collected from localities in the Nile Delta region of Egypt. Isolates were cultivated, identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic susceptibility testing was performed by the broth microdilution method. PCR amplifications were carried out, targeting resistance-associated genes. Thirty-eight Staphylococcus isolates and six Streptococcus isolates could be cultivated. Staphylococcus aureus isolates revealed a high resistance rate to penicillin, ampicillin, clindamycin, and erythromycin. The mecA gene defining methicillin-resistant Staphylococcus aureus, erm(C) and aac-aphD genes was found in 87.5% of each. Coagulase-negative staphylococci showed a high prevalence of mecA, blaZ and tetK genes. Other resistance-associated genes were found. All Streptococcus dysgalactiae isolates carried blaZ, erm(A), erm(B), erm(C) and lnuA genes, while Streptococcus suis harbored erm(C), aphA-3, tetL and tetM genes, additionally. In Streptococcus gallolyticus, most of these genes were found. The Streptococcus agalactiae isolate harbored blaZ, erm(B), erm(C), lnuA, tetK, tetL and tetM genes. Streptococcus agalactiae isolate was analyzed by DNA microarray analysis. It was determined as sequence type 14, belonging to clonal complex 19 and represented capsule type VI. Pilus and cell wall protein genes, pavA, cadD and emrB/qacA genes were identified by microarray analysis.

The public health importance of the genus Campylobacter is attributed to several species causing diarrhea in consumers. Poultry and their meat are considered the most important sources of human campylobacteriosis. In this study, 287 samples from chicken (131 cloacal swabs, 39 chicken skin, 78 chicken meat, and 39 cecal parts) obtained from retail outlets as well as 246 stool swabs from gastroenteritis patients were examined. A representative number of the biochemically identified Campylobacter jejuni isolates were identified by real-time PCR, confirming the identification of the isolates as C. jejuni . Genotyping of the examined isolates ( n = 31) by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) revealed a high discriminatory index of ERIC-PCR ( D = 0.948), dividing C. jejuni isolates of chicken and human origins into 18 profiles and four clusters. The 18 profiles obtained indicated the heterogeneity of C. jejuni . Dendrogram analysis showed that four clusters were generated; all human isolates fell into clusters I and III. These observations further support the existence of a genetic relationship between human and poultry isolates examined in the present study. In conclusion, the results obtained support the speculation that poultry and poultry meat have an important role as sources of infection in the acquisition of Campylobacter infection in humans.

This study was conducted on 100 diseased Nile tilapia (O. niloticus) fish of various sizes collected fromdifferent fish markets in Kaliobia Governorate to estimate the prevalence of Pseudomonas infection anddetection of some virulence genes in the isolated P. aeruginosa strains. The results of bacteriologicalexamination revealed that the prevalence of Pseudomonas septicemia with Pseudomonas speciesisolation 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, 32Pseudomonas species were isolated, 11from liver samples (34.4%); 10 from kidney samples (31.2%); 6from gill samples (18.8%) and 5 from skin samples (15.6%). Moreover, 14 P. anguilliseptica wereisolated 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 theisolated Pseudomonas strains were sensitive to gentamycin; enrofloxacin; norfloxacin; ciprofloxacinand 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 revealedthat, opr L and exo S virulence genes were detected in all six studied strains (100.0%). Meanwhile, phzM virulence gene was detected in 5 out of 6 studied strains (83.3%) and tox A virulence gene wasdetected in 4 out of 6 studied strains (66.7%) i.e., all studied strains were Ps. aeruginosa and all of themwere virulent strains

Prevalence of E.coli among poultry farms was investigated in these studies, which cover differentprovinces in Egypt through examination of 400 chicken samples using standard methods for isolationand identification of E.coli. The result showed presence of E.coli among imported chicks in rate 44%and from local broiler chickens about 75%. The incidence of E.coli in on day old living diseased chickswas(58.3), while the incidence of E.coli from local broiler chickens was (71%) from living diseasedchickens and about (83%) from freshly dead chickens These serotype of E.coli were O63, O103, O125,O158, O44. Antibiogram pattern test indicated the highest rate of resistant against tetracycline groupwhere about 80% followed by the2 β-Lactam antibiotic (73.3%), erythromycin about 63.3% of testedisolate were resistant, florfenicol about 53.3% were resistant , gentamycin was about 46.6% wereresistance , finally ciprofloxacin about 40% of tested isolate were resistant by using disc diffusionmethod