This study is designed to discuss the antimicrobial resistance, virulence determinants and biofilm formation capacity of Enterococcus spp. isolated from milk of sheep and goat with subclinical mastitis in Qena, Egypt. The obtained isolates were identified by the VITEK2 system and 16S rDNA sequencing as E. faecalis, E. faecium, E. casseliflavus and E. hirae. Overall, E. faecalis and E. faecium were the dominant species recovered from mastitic milk samples. The antimicrobial susceptibility test evidenced multidrug resistance of the isolates against the following antimicrobials: oxacillin (89.2.%), followed by vancomycin (75.7%) and linezolid (70.3%). Also, most of these isolates (73%) could form biofilms. For example, 18.9% of Enterococcus strains formed strong biofilm, whereas 32.4% of isolates formed moderate biofilm and 21.6% of isolates formed weak biofilm. The most prevalent resistance genes found in our isolates were blaZ (54%), vanA (40%), ermB (51.4%), tetM (13.5%) and optrA (10.8%). Moreover, asa1 (37.8%), cylA (42.3%), gelE (78.4%), esp (32.4%), EF3314(48.6%) and ace (75.5%) were the most common virulence genes. A significant correlation was found between biofilm formation, multidrug resistance and virulence genes of the isolates. This study highlights several aspects of virulence and harmfulness of Enterococcus strains isolated from subclinical mastitic milk, which necessitates continuous inspection and monitoring of dairy animals.

This study was accomplished to test raw milk and certain dairy products sold in local markets of Qena, Egypt, for the presence of Campylobacter coli and Campylobacter jejuni. A total of 150 samples of raw milk, kareish cheese, and yoghurt (50 samples each) were subjected first to enrichment in Bolton broth at 42°C for 2 days under a microaerobic condition, subsequently campylobacter blood free selective agar plates were cultured and incubated in the same condition of the broth. Based on the morphological and biochemical themes of the growing colonies, it was further classified into Campylobacter spp. The identified isolates were later affirmed by polymerase chain reaction using primers that were designed to locate hipO genes in C. jejuni and glyA in C. coli. Of the total 150 examined samples of raw milk and soft cheese samples; 37 (24.6%) samples were contaminated with Campylobacter spp. C. jejuni was dominating in this study in 20%, 14%, and 8% of the examined raw milk, kareish cheese, and yoghurt samples, respectively. No sample harbored C. coli. Campylobacter spp. could be detected in 24.6% of the investigated samples. C. jejuni isolated from 14% of the total tested samples, while C. coli could not be detected from the examined samples. Campylobacter spp. is rampant in the areas of poor hygienic conditions making products made from raw milk of public health hazard.

Acinetobacter baumannii (A. baumannii) is an opportunistic pathogen associated with nosocomial infections. In this study, 100 raw milk samples were collected from Qena, Egypt, and subjected to conventional and molecular assays to determine the presence of A. baumannii and investigate their antimicrobial resistance and biofilm formation. Our findings revealed that, among the 100 samples, Acinetobacter spp. were found in 13 samples based on CHROM agar results. We further characterized them using rpoB and 16S-23SrRNA sequencing and gyrB multiplex PCR analysis and confirmed that 9 out of the 13 Acinetobacter spp. isolates were A. baumannii and 4 were other species. The A. baumannii isolates were resistant to β-lactam drugs, including cefotaxime (44%), ampicillin-sulbactam and levofloxacin (33.3% for each), imipenem, meropenem and aztreonam (22.2% for each). We observed different antimicrobial resistance patterns, with a multi-antibiotic resistant (MAR) index ranging from 0.2 to 0.3. According to the PCR results, bla_OXA-51 and bla_OXA-23 genes were amplified in 100% and 55.5% of the A. baumannii isolates, respectively, while the bla_OXA-58 gene was not amplified. Furthermore, the metallo-β-lactamases (MBL) genes bla_IMP and bla_NDM were found in 11.1% and 22.2% of isolates, respectively, while bla_VIM was not amplified. Additionally, eight A. baumannii isolates (88.8%) produced black-colored colonies on Congo red agar, demonstrating their biofilm production capacity. These results showed that, besides other foodborne pathogens, raw milk should also be examined for A. baumannii, which could be a public health concern.

The aim of the present work was to investigate the mutual role that may be played by the served dairy food and food handlers in the transmission of methicillin- and vancomycin-resistant Staphylococcus aureus and coagulase-negative Staphylococci to patients who were hospitalized in Qena City, Egypt. A total of 210 samples including 90 dairy food samples which offered to the patients in the hospital, 60 nasal and hand swabs from food handlers working in the hospital, and 60 nasal and diarrheal swabs from patients suffering from diarrhea were investigated for the presence of coagulase-positive S. aureus and coagulase-negative Staphylococci, then isolates were screened for methicillin and vancomycin resistance phenotypically and genotypically. 16s rRNA gene sequencing was employed to construct the neighbor-joining tree. Unlike food samples, both coagulase-positive S. aureus and coagulase-negative Staphylococci occurred in human samples. Methicillin- and vancomycin-resistant coagulase-negative Staphylococci could be detected in 41.7% & 20.8%, 68% & 31.9%, and 81.3% & 55.2% of isolates obtained from dairy food, food handlers, and patients' samples, respectively. Whereas 81% & 64.3%, and 75.4% & 38.6% of coagulase-positive S. aureus obtained from food handlers and patients' samples exhibited resistance to methicillin and vancomycin, respectively. Phenotypic resistance was confirmed molecularly through detection of mecA and vanA genes. A significant role can be played by food and food handlers in the transmission of methicillin- and vancomycin-resistant Staphylococci to patients, which has been proved in this study through the close phylogenetic relation between S. epidermidis isolated from food, food handlers, and patients' diarrheal samples.

Vibrio species can cause foodborne infections and lead to serious gastrointestinal illnesses. The purpose of this research was to detect the Vibrio cholerae and Vibrio parahaemolyticus in raw milk, dairy products, and water samples. Also, it investigated the virulence factors, antibiotic resistance and biofilm formation in isolated bacteria. Conventional and molecular approaches were used to identify the isolates in this study. Vibrio species were detected in 5% of the samples. Vibrio cholerae and Vibrio parahaemolyticus were isolated from 1.25 and 1.5%, respectively, of the total samples. Penicillin resistance was detected in all strains of Vibrio cholerae and Vibrio parahaemolyticus, with a MAR index ranging from 0.16 to 0.5. Four isolates were moderate biofilm producer and three of them were MDR. When Vibrio cholerae was screened for virulence genes, ctxAB, hlyA, and tcpA were found in 80, 60, and 80% of isolates, respectively. However, tdh + /trh + associated-virulence genes were found in 33.3% of Vibrio parahaemolyticus isolates.

Introduction: Listeria monocytogenes is an important foodborne pathogen of public- and animal-health concern globally. The persistence of L. monocytogenes in the dairy-processing environment has multifactorial causes, including lack of hygiene, inefficient cleaning, and improper disinfection practices. Materials and Methods: A total of 300 dairy-product and environmental samples were collected from dairy-cattle facilities and local dairy shops and vendors in Qena, Egypt. Samples were screened for the incidence of Listeria spp. and to detect virulence determinants and disinfectant-resistance genes. Three marine algal species — Caulerpa racemosa, Jania rubens, and Padina pavonica — were collected from Hurghada on the Red Sea coast. Algal extracts were screened using gas chromatography–mass spectrometry. The antimicrobial activity of some marine algal extracts, nanoparticles derived therefrom, and some disinfectants against L. monocytogenes strains were assessed in vitro using agar-well diffusion and liquid-broth methods. The impact of P. pavonica extract on the growth and survival of virulent L. monocytogenes in cheese and whey were clarified. Results and Discussion: The incidence of L. monocytogenes in dairy products and environmental samples was 15.5% and 19%, respectively. The most common toxigenic gene profile found among the isolates was hlyA⁺–inlA⁺–prfA⁺. The sensitivity pattern of L. monocytogenes strains to disinfectant containing alkyl (C_{12– 16}) dimethyl BAC was high compared to other tested quaternary ammonium compounds (QAC) disinfectants tested, which showed lower log reductions against resistant strains. The QAC disinfectant–resistance gene qacH was detected in 40% of the isolates. Potent bactericidal activity of a petroleum ether extract of P. pavonica and silver nanoparticles of P. pavonica were obtained against the virulent L. monocytogenes strain. The population of L. monocytogenes in cheese curd and whey after 14 days was reduced at a rate of 9 log CFU/g and 8 log CFU/mL, respectively due to the effect of P. pavonica extract. After 28 days of storage, L. monocytogenes was completely inactivated in those dairy products. Conclusion: P. pavonica extract showed promising antimicrobial properties, calling for further comprehensive studies prior to it being applied in the food industry to enhance the safety, quality, and shelf life of products and protect public health.