Introduction: Salmonella serovars are one of the primary foodborne pathogens. Poultry consumption is responsible for the majority of disease cases worldwide. The prevalence of virulence determinants among Salmonella serovars appears to be lacking in Egypt. Therefore, this study investigated the occurrence, antibiotic resistance patterns, and virulence gene profiling of Salmonella serovars in broilers. Methodology: Three hundred samples from broiler chickens were examined for the presence of Salmonella by standard microbiological techniques. All Salmonella isolates were tested for their sensitivity against ten antibiotics and subjected to virulence genotyping by polymerase chain reaction (PCR). Results: The overall isolation percentage of Salmonella was 17%. Seven different serovars were found, with the main one being Salmonella Typhimurium (52.94%). Salmonella isolates were sensitive to most of the tested antibiotics, but they exhibited absolute resistance against amoxicillin/clavulanic acid. Nine Salmonella strains (52.94%) were resistant to at least three antibiotics. Further PCR investigations into 17 Salmonella strains revealed different distribution patterns of eight virulence determinants among the isolates. The invA gene was the most prevalent one (100%), followed by hilA (88.24%), stn (58.82%), and fliC genes (52.94%), while each of sopB and pefA genes had a similar prevalence (41.18%), and sefC and spvC genes had the lowest prevalence (11.76 and 5.88%, respectively). PCR genotyping allowed grouping of Salmonella strains into ten genetic profiles. Conclusions: These results will help in understanding the spread of virulence genotypes and antibiotic resistance among Salmonella serovars in broilers.

The present study involved in vivo evaluation of the growth promoting effects of thymol and thymol nanoemulsion and their protection against Salmonella Typhimurium infection in broilers. One-day old 2400 chicks were randomly divided into eight groups; negative and positive control groups fed basal diet without additives and thymol and thymol nanoemulsion groups (0.25, 0.5 and 1% each). At d 23, all chicks except negative control were challenged with S. Typhimurium. Over the total growing period, birds fed 1% thymol nanoemulsion showed better growth performance even after S. Typhimurium challenge, which came parallel with upregulation of digestive enzyme genes (AMY2A, PNLIP and CCK). Additionally, higher levels of thymol nanoemulsion upregulated the expression of MUC-2, FABP2, IL-10, IgA and tight junction proteins genes and downregulated IL-2 and IL-6 genes expression. Moreover, 1% thymol nanoemulsion, and to lesser extent 0.5% thymol nanoemulsion and 1% thymol, corrected the histological alterations of cecum and liver postinfection. Finally, supplementation of 1% thymol, 0.5 and 1% thymol nanoemulsion led to increased Lactobacilli counts and decreased S. Typhimurium populations and downregulated invA gene expression postinfection. This first report of supplying thymol nanoemulsion in broiler diets proved that 1% nano-thymol is a potential growth promoting and antibacterial agent.

Multidrug resistant (MDR) methicillin-resistant Staphylococcus aureus (MRSA) is a superbug pathogen that causes serious diseases. One of the main reasons for the lack of the effectiveness of antibiotic therapy against infections caused by this resistant pathogen is the recalcitrant nature of MRSA biofilms, which results in an increasingly serious situation worldwide. Consequently, the development of innovative biofilm inhibitors is urgently needed to control the biofilm formation by this pathogen. In this work, we thus sought to evaluate the biofilm inhibiting ability of some promising antibiofilm agents such as zinc oxide nanoparticles (Zno NPs), proteinase K, and hamamelitannin (HAM) in managing the MRSA biofilms. Different phenotypic and genotypic methods were used to identify the biofilm producing MDR MRSA isolates and the antibiofilm/antimicrobial activities of the used promising agents. Our study demonstrated strong antibiofilm activities of ZnO NPs, proteinase K, and HAM against MRSA biofilms along with their transcriptional modulation of biofilm (intercellular adhesion A, icaA) and quorum sensing (QS) (agr) genes. Interestingly, only ZnO NPs showed a powerful antimicrobial activity against this pathogen. Collectively, we observed overall positive correlations between the biofilm production and the antimicrobial resistance/agr genotypes II and IV. Meanwhile, there was no significant correlation between the toxin genes and the biofilm production. The ZnO NPs were recommended to be used alone as potent antimicrobial and antibiofilm agents against MDR MRSA and their biofilm-associated diseases. On the other hand, proteinase-K and HAM can be co-administrated with other antimicrobial agents to manage such types of infections.

Foodborne pathogens have been associated with severe and complicated diseases. Therefore, these types of infections are a concern for public health officials and food and dairy industries. Regarding the wide-spread multidrug resistant (MDR) and extensively drug resistant (XDR) foodborne pathogens such as Salmonella Enteritidis (S. Enteritidis), new and alternative therapeutic approaches are urgently needed. Therefore, we investigated the antimicrobial, anti-virulence, and immunostimulant activities of a stable formulation of thymol as thymol nanoemulsion in an in vivo approach. Notably, treatment with 2.25% thymol nanoemulsion led to a pronounced improvement in the body weight gain and feed conversion ratio in addition to decreases in the severity of clinical findings and mortality percentages of challenged chickens with XDR S. Enteritidis confirming its pronounced antimicrobial activities. Moreover, thymol nanoemulsion, at this dose, had protective effects through up-regulation of the protective cytokines and down-regulation of XDR S. Enteritidis sopB virulence gene and interleukins (IL)-4 and IL-10 cytokines as those hinder the host defenses. Furthermore, it enhanced the growth of gut Bifidobacteria species, which increases the strength of the immune system. For that, we suggested the therapeutic use of thymol nanoemulsion against resistant foodborne pathogens. Finally, we recommended the use of 2.25% thymol nanoemulsion as a feed additive for immunocompromised individuals as well as in the veterinary fields.

No abstract

Summary Methicillin‐resistant Staphylococcus aureus (MRSA) has been shown to be the predominant life‐threatening pathogen in Egypt. MRSA is a major cause of severe healthcare‐associated (HA) infections. During the last decades, the incidence of community‐associated (CA) MRSA infections has a complex epidemiology arising from the circulation of different strains in the general population. Moreover, livestock‐associated (LA) MRSA emerged recently becomes an emerging threat to public health. Therefore, it is important to illuminate the differences between CA‐, HA‐ and LA‐MRSA to shed light on their genetic diversity and evolution. This study presents the first data on analysing the correlation between CA‐, LA‐ and HA‐MRSA using antibiogram typing, molecular characteristics and antimicrobial resistance and virulence genes’ profiles. Overall, HA‐MRSA strains tended to be multidrug resistant and less virulent than both LA‐ and CA‐MRSA strains. Importantly, CA‐MRSA strains had a high homology with each of HA‐ and LA‐MRSA. However, no similarity was observed between HA‐ and LA‐MRSA. Our findings suggest that the epidemiological changes in genetic behaviour between HA‐ and LA‐MRSA are due to the presence of CA‐MRSA confirming that CA‐MRSA has created a public health crisis worldwide.

No abstract

Campylobacter jejuni (C. jejuni) are able to colonise and infect domestic poultry and also pose a risk for humans. The aim of this study was to determine the extent of genotypic diversity among C. jejuni isolates recovered from avian and human sources in Egypt. Furthermore, the short variable region (SVR) of flagellin A (flaA) gene was analysed for the presence of allelic variants. Our results showed that C. jejuni isolates differ in their capacity to harbour each of the virulence genes alone or when present in various combinations. The flaA gene was detected in all C. jejuni strains and none of the strains had all the studied virulence genes together. When considering C. jejuni strains from the investigated sources, the cdtC gene was the most similar, while the cdtB and iam genes were the most dissimilar. We could identify 13 novel alleles in the analysed strains. The analyses of virulence gene patterns, flaA gene sequences and allelic variants showed that C. jejuni strains from different sources overlapped largely suggesting potential involvement of poultry in transmitting C. jejuni to humans. We also found that the strains isolated from the same host were highly heterogeneous, with chicken strains exhibiting the highest diversity. Moreover, the human strains were clustered closer to chicken ones than to those from pigeon. The results of this study should be taken into consideration when assessing the epidemiology and risk potential of Egyptian C. jejuni not only in poultry, but also in humans.