Background and Aim: Food of animal origin is considered a major source of foodborne diseases. In this context, multidrug-resistant (MDR) Escherichia coli pose a serious hazard to public health due to the consumption of food contaminated with antibiotics that are used for the treatment of various bacterial infections in farm animals. Therefore, this study aimed to determine the effect of the excessive use of antibiotics on the development of MDR E. coli strains in Egyptian poultry, dairy, and meat farms. Materials and Methods: A total of 1225 samples were randomly collected from poultry, dairy, and meat products intended for human consumption in different governorates. E. coli were isolated from the collected samples and subjected to biochemical identification and antibiotic sensitivity tests with antibiotics commonly used in human and veterinary medicine. Then, amoxicillin (AML)- and oxytetracycline (OT)-resistant E. coli isolates were subjected to a polymerase chain reaction test to detect the blaTEM and tetA genes, respectively. Results: E. coli were isolated from 132 out of 350, 148 out of 350, 177 out of 350, and 35 out of 175 poultry, milk, meat, and human samples, respectively. Most of the isolates expressed multidrug resistance, and resistance genes (blaTEM and tetA) were detected in all the tested AML- and OT-resistant E. coli isolates. Conclusion: Foods of animal origin may represent a source of MDR E. coli, which can be a major threat to public health.

Background and Aim: Coagulase-negative staphylococci (CNS) are becoming the major cause of clinical and subclinical bovine mastitis around the world. This study aims to estimate the prevalence, antibiogram, and frequency of the methicillinresistant (MR) (mecA) gene in CNS collected from cows with subclinical mastitis.Materials and Methods: Thirty-four milk samples were collected from 20 cows. Fifteen subclinical mastitis samples (~44.12%) were identified as CNS isolates. The Vitek2 compact system method was employed for the identification of the species. Furthermore, antibiotic sensitivity tests were performed against 10 different antibiotics for CNS strains. The mecA gene from isolated CNS was detected by conventional polymerase chain reaction (PCR).Results: Staphylococcus haemolyticus was the most predominant isolated species with an incidence of 33.3% (5/15 isolates), followed by 26.7% for Staphylococcus sciuri and Staphylococcus vitamins (4/15 isolates), and 13.3% for Staphylococcus vitulinus (2/15 isolates), respectively. The highest resistance rates were determined to be 40% (6/15 isolates) against penicillin and oxacillin (OX), 33.3% (5/15 isolates) against clindamycin, 13% (2/15 isolates) against chloramphenicol, amoxicillin, and erythromycin, and 5% (1/15 isolates) against ciprofloxacin, respectively. The results revealed that the isolates were resistant to one or more antimicrobial agents, with five isolates displaying multiple antimicrobial resistance. Furthermore, the results exhibit that all CNS isolates had the mecA gene at 310 bp with a 100% frequency. Moreover, for detecting MR isolates, there are significant discrepancies between phenotypic and genotypic approaches, and only 6/15 CNS isolates phenotypically demonstrated OX resistance. Conclusion:The results emphasize the necessity of frequent monitoring of phenotypic and genotypic profiles of CNS isolates to ensure effective control measures and the prevention of multidrug resistance strain evolution.

Acacia nilotica (synonym: Vachellia nilotica (L.) P.J.H.Hurter and Mabb.) is considered an important plant of the family Fabaceae that is used in traditional medicine in many countries all over the world. In this work, the antiviral potentialities of the chemically characterized essential oils (EOs) obtained from the bark and fruits of A. nilotica were assessed in vitro against HAV, HSV1, and HSV2. Additionally, the in silico evaluation of the main compounds in both EOs was carried out against the two proteins, 3C protease of HAV and thymidine kinase (TK) of HSV. The chemical profiling of the bark EOs revealed the identification of 32 compounds with an abundance of di- (54.60%) and sesquiterpenes (39.81%). Stachene (48.34%), caryophyllene oxide (19.11%), and spathulenol (4.74%) represented the main identified constituents of bark EO. However, 26 components from fruit EO were assigned, with the majority of mono- (63.32%) and sesquiterpenes (34.91%), where trans-caryophyllene (36.95%), Z-anethole (22.87%), and γ-terpinene (7.35%) represented the majors. The maximum non-toxic concentration (MNTC) of the bark and fruits EOs was found at 500 and 1000 µg/mL, respectively. Using the MTT assay, the bark EO exhibited moderate antiviral activity with effects of 47.26% and 35.98% and a selectivity index (SI) of 2.3 and 1.6 against HAV and HSV1, respectively. However, weak activity was observed via the fruits EO with respective SI values of 3.8, 5.7, and 1.6 against HAV, HSV1, and HSV2. The in silico results exhibited that caryophyllene oxide and spathulenol (the main bark EO constituents) showed the best affinities (ΔG = −5.62, −5.33, −6.90, and −6.76 kcal/mol) for 3C protease and TK, respectively. While caryophyllene (the major fruit EO component) revealed promising binding capabilities against both proteins (ΔG = −5.31, −6.58 kcal/mol, respectively). The molecular dynamics simulation results revealed that caryophyllene oxide has the most positive van der Waals energy interaction with 3C protease and TK with significant binding free energies. Although these findings supported the antiviral potentialities of the EOs, especially bark EO, the in vivo assessment should be tested in the intraoral examination for these EOs and/or their main constituents.

The biosynthesis of silver nanoparticles (Ag-NPs) is a new methodology in nanotechnology with a hopeful implementation in medicine, food control, and pharmacy. The objective of the present research was to conduct a green synthesis of Ag-NPs using the cell-free supernatant of Lactobacillus plantarum and Lactobacillus brevis and evaluate their antibacterial and antifungal activities. The production of Ag-NPs was confirmed by the color alteration from yellow to brown. Using the UV-visible spectrophotometer, the biosynthesized Ag-NPs indicated an absorption peak at 410 nm. The transmission electron microscope was used for the determination of the size and morphology of the nanoparticles. Nanoparticles appeared in spherical or polyhedral form, poly-dispersed and their diameter ranged from 5 to 40 nm. The X-ray diffraction analysis exhibited the crystalline nature of the particles with a face-centered cubic (FCC) structure. The biosynthesized Ag-NPs were evaluated for their antimicrobial efficiency using the agar well diffusion method. The antibacterial activity of Ag-NPs was more potent against Gram-negative bacteria than Gram-positive bacteria. Ag-NPs synthesized from Lactobacillus plantarum recorded the maximum activity against Escherichia coli (ATCC® 10536™) and Pseudomonas (ATCC® 27853™) bacteria, while those synthesized from Lactobacillus brevis recorded the maximum activity against Escherichia coli (ATCC® 35218™). Ag-NPs synthesized from Lactobacillus plantarum and Lactobacillus brevis showed antifungal activity against Candida albicans (ATCC® 10231™). The effect of these nanoparticles on Escherichia coli (ATCC® 10536™) was examined and imaged by a transmission electron microscope that indicated damage to the plasma membrane and cell wall. In conclusion, the biosynthesized Ag-NPs have applications as antimicrobial agents in the medicine and food industry.

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