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Recently, cellulose nanocrystals (CNs) have attracted wide attention owing to their superior properties compared to their bulk materials. For example, they represent an outstanding model for fabricating green metallic/metal oxide nanoparticles (NPs). In this study, two CNs (carboxylated CNs and sulfated CNs) extracted from agro-wastes of palm sheath fibers were used as templates for the facile and green synthesis of ZnO NPs by employing the sono-co-precipitation method. The obtained nanomaterials were characterized using TEM, EDX, UV–visible, DLS, FT-IR, and XRD analysis. As a result, the size and concentration of synthesized ZnO NPs were inversely proportional to one another and were affected by the CNs utilized and the reaction temperature used. Contagious diseases incited by multifarious toxigenic bacteria present severe threats to human health. The fabricated bio-nanocomposites were evaluated in terms of their antimicrobial efficacy by agar well diffusion method and broth microdilution assay, showing that CN–ZnO bio-nanocomposites were effective against the tested Gram-negative ( Escherichia coli and Salmonella ) and Gram-positive ( Listeria monocytogenes and Staphylococcus aureus ) bacteria. The influence of the subinhibitory concentrations of these suspensions on the expression of the most critical virulence toxin genes of the tested strains was effective. Significant downregulation levels were observed through toxigenic operons to both fabricated CN–ZnO bio-nanocomposites with a fold change ranging from 0.004 to 0.510, revealing a decline in the capacity and virulence of microorganisms to pose infections. Therefore, these newly fabricated CNS–ZnO bio-nanocomposites could be employed rationally in food systems as a novel preservative to inhibit microbial growth and repress the synthesis of exotoxins.

This study was divided into two parts. The first part involved the isolation, and detection of the prevalence and antimicrobial resistance profile of Aeromonas hydrophila, Pseudomonas aeruginosa , and Vibrio species from Nile tilapia fish and marine aquatic water. One hundred freshly dead Nile tilapia fish were collected from freshwater aquaculture fish farms located in Al-Abbassah district, Sharkia Governorate, and 100 samples of marine aquatic water were collected from fish farms in Port Said. The second part of the study focused on determining the in vitro inhibitory effect of dual-combination of AgNPs-H2O2 on bacterial growth and its down regulatory effect on crucial virulence factors using RT-PCR. The highest levels of A. hydrophila and P. aeruginosa were detected in 43%, and 34% of Nile tilapia fish samples, respectively. Meanwhile, the highest level of Vibrio species was found in 37% of marine water samples. Additionally, most of the isolated A. hydrophila, P. aeruginosa and Vibrio species exhibited a multi-drug resistance profile. The MIC and MBC results indicated a bactericidal effect of AgNPs-H2O2. Furthermore, a transcriptional modulation effect of AgNPs-H2O2 on the virulence-associated genes resulted in a significant down-regulation of aerA, exoU, and trh genes in A. hydrophila, P. aeruginosa, and Vibrio spp ., respectively. The findings of this study suggest the effectiveness of AgNPs-H2O2 against drug resistant pathogens related to aquaculture.

The emergence of pandrug-resistant (PDR) and extensive drug-resistant (XDR) methicillin-resistant and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) isolates from bovine milk samples along with biofilm formation ability and harboring various virulence genes complicates the treatment of bovine mastitis and highlights the serious threat to public health. This study investigated for the first time the frequency, antimicrobial resistance profiles, biofilm-forming ability, virulence factors, spa and staphylococcal cassette chromosome mec (SCC mec ) types of MRSA and VRSA isolated from clinical and subclinical bovine mastitis in Egypt. A total of 808 milk samples were collected from each quarter of 202 dairy animals, including 31 buffaloes and 171 cattle. The frequency of mastitis in the collected milk samples was 48.4% (60/124) in buffaloes and 29.2% (200/684) in cattle. A total of 65 Staphylococcus species isolates were recovered, including 27 coagulase-positive S. aureus (CoPS) isolates and 38 coagulase-negative staphylococci (CoNS). The CoNS included 27 mammaliicocci (20 Mammaliicoccus lentus and 7 M. sciuri ) and 11 Non-aureus staphylococci ( S. lugdunensis ) isolates. All the CoPS isolates were mec A positive and resistant to 20–33 tested antimicrobials with multiple antibiotic resistance index ranging from 0.61 to 1. Three isolates were PDR, four were XDR, and 20 were multidrug resistant isolates. VRSA was detected in 85.2% of CoPS isolates with minimal inhibitory concentration (MIC) ranging from 64 to 1024 µg/mL. The van A gene was found in 60.8%, van B in 73.9%, and both genes in 43.5% of VRSA isolates. All the CoPS isolates exhibited biofilm formation ability, with 55.6% being strong, and 44.4% moderate biofilm producers, and harbored ica A (74.1%) and ica D (74.1%) biofilm-forming genes. All S. aureus isolates harbored both beta-haemolysin ( hlb ) and leucotoxin ( luk MF) genes, while 44.4% were positive for toxic shock syndrome toxin ( tsst ) gene. Enterotoxin genes sea , seb , sec , sed , and see were found in 59.3%, 40.7%, 18.5%, 33.3%, and 14.8% of isolates, respectively. Additionally, 70.4% of the isolates had  spa X-region gene, and exhibited eight different MRSA spa types (t127, t267, t037, t011, t843, t1081, t2663, and t1575), with spa t127 being the most common. Three SCC mec types (I, II and III) were identified, with SCC mec I being predominant, and were further classified into subtypes 1.1.1, 1.1.2, 1.n.1, and 4.1.1. The ability of MRSA and VRSA isolates to produce biofilms and resist antimicrobials highlights the serious threat these pathogens pose to bovine milk safety, animal welfare, and public health. Therefore, strict hygiene practices and antimicrobial surveillance are crucial to reduce the risk of MRSA and VRSA colonization and dissemination.

The present study aimed to isolate Pasteurella multocida (P. multocida) from pulmonary cases in several avian species and then investigate the histopathological features, antimicrobial resistance determinants, virulence characteristics, and risk factors analysis of the isolates in each species in correlation with epidemiological mapping of pasteurellosis in Sharkia Governorate, Egypt. The obtained data revealed a total occurrence of 9.4% (30/317) of P. multocida among the examined birds (chickens, ducks, quails, and turkeys). The incidence rate was influenced by avian species, climate, breed, age, clinical signs, and sample type. Antimicrobial susceptibility testing revealed that all isolates were sensitive to florfenicol and enrofloxacin, while 86.6 and 73.3% of the isolates displayed resistance to amoxicillin-clavulanic acid and erythromycin, respectively. All of the P. multocida isolates showed a multiple-drug resistant pattern with an average index of 0.43. Molecular characterization revealed that the oma87, sodA, and ptfA virulence genes were detected in the all examined P. multocida isolates. The ermX (erythromycin), blaROB-1 (β-lactam), and mcr-1(colistin) resistance genes were present in 60, 46.6, and 40% of the isolates, respectively. Ducks and quails were the most virulent and harbored species of antimicrobial-resistant genes. These results were in parallel with postmortem and histopathological examinations which detected more severe interstitial pneumonia lesions in the trachea and lung, congestion, and cellular infiltration especially in ducks. Epidemiological mapping revealed that the Fakous district was the most susceptible to pasteurellosis infection. Thus, farmers are recommended to monitor their flocks for signs of respiratory disease, seek veterinary care promptly if any birds are sick, and avoid the random usage of antibiotics. In conclusion, this study presents a comprehensive picture of the risk factors in correlation to the pathognomonic characteristics of P. multocida infection in poultry sectors to help in developing more effective strategies for prevention and control.

A total of 220 birds of age ranging from 3 to 14 weeks old were collected from several backyards and different farms in Sharkia Governorate, Egypt, and surveyed for the presence of fowl cholera. Twenty Pasteurella multocida from chickens (15/145, 10%) and ducks (5/75, 6%) were bacteriologically isolated, and it was shown that the infection was significantly related to age and breed. Capsular typing, using multiplex polymerase chain reaction (PCR), demonstrated that all strains were type A (100%). Disk diffusion assay towards ten antimicrobials revealed high susceptibilities to amikacin, doxycycline, chloramphenicol, and neomycin with varying degrees. Doxycycline was effective at the lowest concentration (MIC 0.125–1 µg/ml). Multidrug resistance was detected with a percentage of 25%. Multidrug-resistant isolates (five isolates) were subjected to study their pathogenicity in embryonated chicken eggs (ECE). The results showed a variation in indices between different dilutions of the tested strains. The resulting pathogenicity indices showed significant differences (P < 0.05) according to the origin and dilution of the isolate. From the original inoculum to 10–4 dilutions, the mortality of inoculated embryos occurred within 1–2 days with pathological findings, including maceration and lesions on chorioallantoic membrane (CAM). From dilutions ranging from 10–5 to 10–9, no death occurred until 7 days post-inoculation, but a variation in the lesions on CAM was observed. In conclusion, P. multocida serogroup A could be intensely pathogenic for mature chickens thus causing considerable economic losses, and PCR provides a suitable technique for early and rapid diagnosis of fowl cholera.

This study demonstrates the novel therapeutic potential of Paratapes undulata for mitigating Vibrio alginolyticus infection in red tilapia. In vivo, P. undulata significantly improved growth by approximately 362% in group G3 (Clam-treated Control) and 284% in group G4 (Clam-treated Infected), compared to the infected control group (G2), and reduced mortality by 100% in group G3 and 75% in group G4, compared to the infected control group (G2), and alleviated clinical signs, correlating with enhanced hematological and biochemical profiles, and reduced tissue damage. Mechanistically, P. undulata modulated the immune response by shifting cytokine balance towards anti-inflammation, enhanced antioxidant capacity, and directly inhibited Vibrio alginolyticus virulence. Gas Chromatography–Mass Spectrometry and Fourier-Transform Infrared Spectroscopy analyses revealed the presence of bioactive compounds contributing to these effects. These findings establish P. undulata as a promising, natural, and sustainable biocontrol agent for vibriosis in aquaculture, offering a novel strategy for disease management and reducing reliance on antibiotics. This study suggests that P. undulata can be effectively incorporated into aquaculture feed or water treatments to prevent and manage vibriosis outbreaks.

Surface-growing antibiotic-resistant pathogenic Salmonella is emerging as a global health challenge due to its high economic loss in the poultry industry. Their pathogenesis, increasing antimicrobial resistance, and biofilm formation make them challenging to treat with traditional therapy. The identification of antimicrobial herbal ingredients may provide valuable solutions to solve this problem. Therefore, our aim is to evaluate the potency of nano garlic as the  alternative of choice against multidrug-resistant (MDR) Salmonella isolates using disc diffusion and microdilution assays. Then, checkerboard titration in trays was applied, and FIC was measured to identify the type of interaction between the two antimicrobials. A disc diffusion assay revealed that neomycin was the drug of choice. The range of nano garlic MIC was 12.5–25 μg/ml, while the neomycin MIC range was 32–64 μg/ml. The FIC index established a synergistic association between the two tested drugs in 85% of isolates. An experimental model was used including nano garlic and neomycin alone and in combination against Salmonella infection. The combination therapy significantly improved body productivity and inhibited biofilm formation by more than 50% down regulating the CsgBAD, motB , and sipA operons, which are responsible for curli fimbriae production and biofilm formation in Salmonella serotypes.

Objectives: Ducks suffer a huge economic loss as a result of infections with Pasteurella multocida and Riemerella anatipestifer, which cause high morbidity and mortality. Because these patho¬gens induce similar clinical symptoms when coinfections occur, it is very difficult to differentiate between them based just on clinical signs. Hence, these major pathogens must be quickly and accurately detected. Materials and Methods: A total of 104 birds ranging from 2 days to 4 weeks old were collected from Egyptian farms, and the outcomes were compared statistically. Conventional cultural iden¬tification procedures and a direct multiplex polymerase chain reaction assay were utilized to recognize both pathogens in a single tube reaction simultaneously. Then, the obtained isolates were characterized phenotypically and genotypically. Results: Clinical signs appear at 2–4 weeks of age with respiratory distress (dyspnea), white fluid feces, and stunting. The scrutinized data demonstrated a significantly higher detection rate by PCR directly compared to classical culture procedures. Pasteurella multocida was detected only by PCR. The disc diffusion technique against ten antibiotics showed absolute susceptibilities to amik¬acin, doxycycline, and florfenicol. High levels of beta-lactam resistance were observed. Riemerella anatipestifer isolates were screened for pathogenicity and plasmid-borne blaTEM genes. All six isolates harbored five virulence genes: aspC, RA46, m28, pstS, and Nlp/P60. Moreover, blaTEM was identified into four isolates and deposited to GenBank with accession numbers OP347083, OP347084, OP347085, and OP347086. Conclusion: These results suggest advanced PCR assays can be applied to the field for rapid and valuable diagnosis of two significant pathogens and focus on the worth of ducks in the propaga¬tion of transferable antibiotic resistance genes into the environment.

Multidrug-resistant (MDR) Salmonella remains a significant global health threat. This study aimed to explore the potential of essential oil components as novel inhibitors of the Salmonella MDR efflux pumps AcrAB and AcrD. Salmonella isolates were characterized for serotype, antibiotic resistance, and efflux pump activity. Essential oil components were screened for inhibitory effects using phenotypic and genotypic methods. In silico docking and molecular dynamics simulations were conducted to investigate binding interactions and stability. Salmonella Typhimurium was the predominant serotype with high MDR rates. Efflux pump activity was prevalent. Cumin and cinnamon oils demonstrated promising inhibitory effects on these pumps. Molecular docking simulations revealed strong binding affinities of analyzed compounds to the AcrAB and AcrD binding pocket. The 2-methyl-1-(p-tolyl)propan-2-ol exhibited higher stability within the AcrAB binding pocket compared to (1S,3R,5R)-1-isopropyl-4-methylenebicyclo[3.1.0]hexan-3-ol within the AcrD binding pocket. Treatment with these oils significantly downregulated efflux pump genes (robA, acrB, mdtB, acrF, acrD, soxS, mdsB, marA). The novel approach of combining in silico and molecular dynamics simulations with precise gene expression analysis provides a valuable framework for future studies aimed at combating MDR Salmonella efflux pumps.

The extensive use of antimicrobial agents in broiler farms causes the emergence of antimicrobial resistance of  E. coli  producing severe economic losses to the poultry industry; therefore, monitoring the transmission of ESBL  E. coli  is of great significance throughout broiler farms. For this reason, we investigated the efficiency of competitive exclusion (CE) products to control the excretion and transmission of ESBL-producing  E. coli  in broiler chickens. Three hundred samples from 100 broiler chickens were screened for the incidence of  E. coli  by standard microbiological techniques. The overall isolation percentage was 39% and differentiated serologically into ten different serotypes: O158, O128, O125, O124, O91, O78, O55, O44, O2, and O1. The isolates represented absolute resistance to ampicillin, cefotaxime, and cephalexin. The effectiveness of CE (commercial probiotic product; Gro2MAX) on ESBL-producing  E. coli  (O78) isolate transmission and excretion was studied in vivo. The results showed that the CE product has interesting properties, making it an excellent candidate for targeted drug delivery by inhibiting bacterial growth and downregulating biofilm, adhesins, and toxin-associated genes loci. The histopathological findings demonstrated the capability of CE in repairing internal organ tissues. Our outcomes suggested that the administration of CE (probiotic products) in broiler farms could be a safe and alternative approach to control the transmission of ESBL-producing virulent E. coli  in broiler chickens.