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Antibiotic resistance is an increasing threat, requiring novel therapeutic solutions. Metal nanoparticles e.g., zinc oxide nanoparticles (ZnO NPs) exhibited the potential against many bacterial pathogens. Strains of Salmonella enterica serovar Typhi resistant to ceftriaxone were reported first from Pakistan in 2016. Since then, S. Typhi is a pathogen of concern globally owing to its rapidly emerging resistance potential against many last resort antibiotics. In the present study, in vitro and in vivo antimicrobial activity of ZnO NPs against multidrug resistant (MDR) and extensively drug resistant (XDR) Salmonella Typhi strains from Pakistan was evaluated. Zinc oxide green nanoparticles (ZnO GNPs), synthesized from Aloe vera, were characterized by SEM, XRD, UV-vis and Raman spectroscopy. In vitro antibacterial activity of two different concentrations of ZnO GNPs (7 and 15%) was checked using agar well diffusion method. Further, broth microdilution and time kill assays were performed using the ZnO GNPs. In vivo assays were conducted in BALB/c mice sepsis models. In all the three methods, agar well diffusion assay broth microdilution and time kill assay, different zinc oxide dihydrate precursor concentrations had shown the antibacterial activity. The minimum inhibitory concentration (MIC) of ZnO GNPs nanoparticles against MDR and XDR S. Typhi strains was found as 16 to 64 µg/ml. In vivo experiment has shown a significant decrease in CFU/ml in the mice treated with ZnO GNPs as compared to the control group. Our findings have revealed that ZnO GNPs have significant antibacterial activity against MDR and XDR S. Typhi, both in vitro and in vivo., (© 2024. The Author(s) under exclusive licence to Sociedade Brasileira de Microbiologia.)

Importance: Antimicrobial resistance (AMR) is a serious public health threat. AMR bacteria and their resistance determinants in food can be transmitted to humans through the food chain and by direct contact and disseminate directly to the environment., Objective: This study examined the AMR characteristics and transferable R plasmids in Escherichia coli isolated from meat ducks raised in an open-house system., Methods: One hundred seventy-seven (n = 177) commensal E. coli were examined for their antimicrobial susceptibilities and horizontal resistance transfer. The plasmids were examined by PCR-based plasmid replicon typing (PBRT) and plasmid multi-locus sequence typing (pMLST)., Results: The highest resistance rate was found against ampicillin (AMP, 83.0%) and tetracycline (TET, 81.9%), and most isolates exhibited multidrug resistance (MDR) (86.4%). The R plasmids were conjugally transferred when TET (n = 4), AMP (n = 3), and chloramphenicol (n = 3) were used as a selective pressure. The three isolates transferred resistance genes either in AMP or TET. The bla CTX-M1 gene resided on conjugative plasmids. Five replicon types were identified, of which Inc FrepB was most common in the donors (n = 13, 38.4%) and transconjugants (n = 16, 31.2%). Subtyping F plasmids revealed five distinct replicons combinations, including F47:A-:B- (n = 2), F29:A-:B23 (n = 1), F29:A-:B- (n = 1), F18:A-B:- (n = 1), and F4:A-:B- (n = 1). The chloramphenicol resistance was significantly correlated with the other AMR phenotypes ( p < 0.05)., Conclusions and Relevance: The meat ducks harbored MDR E. coli and played an important role in the environmental dissemination of AMR bacteria and its determinants. This confirms AMR as a health issue, highlighting the need for routine AMR monitoring and surveillance of meat ducks., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Korean Society of Veterinary Science.)

The advent of aquaculture has been one of the most significant shifts in world food supply during the last century. Aquaculture has rapidly expanded and become a global food industry, spurred by population expansion, increased seafood consumption, and decreased captured fisheries. Nonetheless, the exponential growth of aquaculture has emerged as a significant contributor to anthropogenic changes. Unexpectedly, the result has focused in the emergence and spread of new diseases. The Asian sea bass ( Lates calcarifer ) is an economically important species in aquaculture, contributing significantly to the global seafood market. However, bacterial diseases have emerged as a major concern, affecting both wild and cultured populations of this species. The most prevalent bacterial pathogens are streptococcus, vibriosis, nocardiosis, tenacibaculosis, and pot-belly disease. Therefore, this review aims to comprehensively analyze both emerging and non-emerging bacterial diseases affecting L. calcarifer and explore potential management approaches for their control. Through an extensive literature survey and critical evaluation of research findings, this review highlights the current understanding of bacterial diseases in L. calcarifer and proposes strategies for better disease management. In addition, this review looks at the rise and characteristics of aquaculture, the major bacterial pathogens of L. calcarifer and their effects, and the specific attributes of disease emergence in an aquatic rather than terrestrial context. It also considers the potential for future disease emergence in L. calcarifer due to aquaculture expansion and climate changes., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 Published by Elsevier Ltd.)

Antimicrobial agents are used to treat microbial ailments, but increased use of antibiotics and exposure to infections in healthcare facilities and hospitals as well as the excessive and inappropriate use of antibiotics at the society level lead to the emergence of multidrug-resistant (MDR) bacteria. Antimicrobial resistance (AMR) is considered a public health concern and has rendered the treatment of different infections more challenging. The bacterial strains develop resistance against antimicrobial agents by limiting intracellular drug accumulation (increasing efflux or decreasing influx of antibiotics), modification and inactivation of drugs and its targets, enzymatic inhibition, and biofilm formation. However, the driving factors of AMR include the sociocultural and economic circumstances of a country, the use of falsified and substandard medicines, the use of antibiotics in farm animals, and food processing technologies. These factors make AMR one of the major menaces faced by mankind. In order to promote reciprocal learning, this article summarizes the current AMR situation in Pakistan and how it interacts with the health issues related to the COVID-19 pandemic. The COVID-19 pandemic aids in illuminating the possible long-term impacts of AMR, which are less immediate but not less severe since their measures and effects are equivalent. Impact on other sectors, including the health industry, the economy, and trade are also discussed. We conclude by summarizing the several approaches that could be used to address this issue., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)