Resistance profiles, virulence and antimicrobial resistance genes of XDR S. Enteritidis and S. Typhimurium.

Avian salmonellosis is concomitant with high financial crises in the poultry industry as well as food-borne illness in man. The present study is designed to investigate the emergence of Salmonella Enteritidis and Salmonella Typhimurium in diseased broilers, resistance profiles, and monitoring virulence and antibiotic resistance genes. Consequently, 450 samples (cloacal swabs, liver, and spleen) were collected from 150 diseased birds from different farms in Giza Governorate, Egypt. Subsequently, the bacteriological examination was done. Afterward, the obtained Salmonella isolates were tested for serogrouping, antibiogram, PCR monitoring of virulence (invA, stn, hilA, and pefA), and antimicrobial resistance genes (blaTEM, blaCTX-M, blaNDM, ermA, sul1, tetA, and aadA1). The total prevalence of Salmonella in the examined diseased broilers was 9.3%, and the highest prevalence was noticed in cloacal swabs. Among the recovered Salmonella isolates (n = 35), 20 serovars were recognized as S. Enteritidis and 15 serovars were identified as S. Typhimurium. Almost 60% of the retrieved S. Enteritidis serovars were extensively drug-resistant (XDR) to seven antimicrobial classes and inherited sul1, blaTEM, tetA, blaCTX-M, ereA, and aadA1 genes. Likewise, 25% of the recovered S. Enteritidis serovars were multidrug-resistant (MDR) to six classes and have sul1, blaTEM, tetA, blaCTX-M, and ereA resistance genes. Also, 66.7% of the retrieved S. Typhimurium serovars were XDR to seven classes and have sul1, blaTEM, tetA, blaCTX-M, ereA, and aadA1 genes. Succinctly, this report underlined the reemergence of XDR S. Typhimurium and S. Enteritidis in broiler chickens. Meropenem and norfloxacin exposed a hopeful antimicrobial activity toward the re-emerging XDR S. Typhimurium and S. Enteritidis in broilers. Moreover, the recurrence of these XDR Salmonella strains poses a potential public health threat.

Simultaneous Action of Silymarin and Dopamine Enhances Defense Mechanisms Related to Antioxidants, Polyamine Metabolic Enzymes, and Tolerance to Cadmium Stress in Phaseolus vulgaris.

Silymarin (Sm) and dopamine (DA) act synergistically as potential antioxidants, mediating many physiological and biochemical processes. As a first report, we investigated the synergistic effect of Sm and DA in mitigating cadmium stress in Phaseolus vulgaris plants. Three experiments were conducted simultaneously using 40 cm diameter pots to elucidate how Sm and DA affect cadmium tolerance traits at morphological, physiological, and biochemical levels. Cadmium stress triggered a marked reduction in growth, productivity, and physio-biochemical characteristics of common bean plants compared to unstressed plants. Seed priming (SP) and foliar spraying (FS) with silymarin (Sm) or dopamine (DA) ((DA (SP) + Sm (FS) and Sm (SP) + DA (FS)) ameliorated the damaging effects of cadmium stress. Sm seed priming + DA foliar spraying (Sm (SP) + DA (FS)) was more efficient. The treated stressed common bean plants showed greater tolerance to cadmium stress by diminishing oxidative stress biomarkers (i.e., O2•-, H2O2, and MDA) levels through enhanced enzymatic (SOD, CAT, POD, APX) and non-enzymatic (ascorbic acid, glutathione, α-tocopherol, choline, phenolics, flavonoids) antioxidant activities and osmoprotectants (proline, glycine betaine, and soluble sugars) contents, as well as through improved photosynthetic efficiency (total chlorophyll and carotenoids contents, photochemical activity, and efficiencies of carboxylation (iCE) and PSII (Fv/Fm)), polyamines (Put, Spd, and Spm), and polyamine metabolic enzymes (ADC and ODC) accumulation. These findings signify that Sm and DA have remarkable anti-stress effects, which can help regulate plant self-defense systems, reflecting satisfactory plant growth and productivity. Thus, realizing the synergistic effect of Sm and DA in cadmium tolerance confers potential new capabilities for these compounds to function in sustainable agriculture.

Biogenic and characterizations of new silver nanoparticles stabilized with indole acetic acid derived from Azospirillum brasilense MMGH-SADAT1, their bioactivity, and histopathological assessment in rats.

An Egyptian rhizobacterium Azospirillum sp. isolated from Sadat city was able to produce indole acetic acid (IAA) up to (30.59 µg/ml). The isolate was identified biochemically and by 16S rRNA sequencing which showed 99.9% similarity to Azospirillum brasilense. The new isolate has been registered in Genbank with accession number MH179119.1. Extracted IAA was used as reducing or stabilizing agent of sliver nanoparticles (AgNPs). Successful fabrication of biogenic IAA-AgNPs was confirmed by Fourier Transform Infrared Spectrophotometer (FTIR) analysis of IAA which showed absorbance peak at 3434.78 cm-1 due to the N-H stretch of primary amines. Highly resolution Transmission Electron Microscopy (HR-TEM) showed AgNPs coating or capping with IAA in spherical shaped with size ranged from 6.01 to 44.02 nm. Energy dispersive X-ray (EDX) analysis revealed that Ag+ ions were attached to the surface of IAA-AgNPs particles. HR-TEM examination showed cell wall damage of Citrobacter freundii cells after exposure to IAA-AgNPs leading to cell death. In vivo results showed that C. freundii infection of rats induced significant increase in liver and kidney functions and deleterious histopathological alteration in rat's tissues. However, treatment by extracted IAA and IAA-AgNPs could normalize the biochemical and histopathological alterations occurred in infected rats. This is the first study to prove that IAA extracted from Azospirillum brasilense is a hopeful capping agent for NPs which has potential to protect against pathogenic infections, nontoxic and/or safe on rat's metabolisms.