CHRISTIAN XEDZRO

Abstract Aims This study aims to investigate the genomic profile of a multidrug-resistant Escherichia coli strain, 160-11H1, co-carrying an extended-spectrum β-lactamase (ESBL) and the plasmid-mediated mobile colistin resistance gene, mcr-5. Methods and results The entire genome of the strain was sequenced using Illumina MiSeq and Oxford Nanopore platforms, and de novo assembly was performed using Unicycler. The genome size was 5 031 330 bp and comprised 5140 coding sequences. mcr-5 and an ESBL-encoding gene, blaSHV-12, providing resistance to clinically important antimicrobials, including colistin (minimum inhibitory concentration [MIC]: 8 µg ml−1) and extended-spectrum cephalosporins (MIC: >32 µg ml−1) were detected. mcr-5 was carried on a Tn3-type transposase, being in an operon with a ChrB-domain protein and an uncharacterized major facilitator superfamily-type transporter on a conjugative plasmid of the IncFII backbone. The blaSHV-12 gene was inserted into tniA putative transposase gene in the IncFIA/FIB/FIC multireplicon plasmid. The strain belonged to sequence type (ST) 10, CH-type fumC11/fimH54, serotype O4:H12, and phylogroup A, and carried several virulence genes associated with heat survival, colonization, fitness, and conjugation. Conclusions This study presents the first identification of polymyxin-resistant E. coli co-carrying mcr-5 and ESBL genes in meat from Japan, highlighting the critical need for routine investigations of these genes within food ecosystems.

DNA methylation is a well-studied epigenetic modification that regulates gene expression, maintains genome integrity, and influences cell fate. It is strictly regulated by a group of enzymes known as DNA methyltransferases (DNMTs). Most DNA methylation occurs at cytosines within symmetrical CpG dinucleotide base pairs, often located at gene promoters or other regulatory elements. Thus, methylation of a promoter CpG island leads to stable transcriptional repression of the associated gene. Nonetheless, abnormal gene expression caused by alterations in DNA methylation has been linked to infertility in both males and females, as well as to reproductive potential and improper post-fertilization embryo development. Recent epigenetic advancements have highlighted the significant association between epigenetic modification and reproductive health outcomes, garnering considerable attention. In this review, we explore significant advancements in understanding DNA methylation, emphasizing its establishment, maintenance, and functions in male and female reproductive sex cells. We also shed light on the recent discoveries on the influence of environmental exposures, nutrition, infection, stress, and lifestyle choices on DNA methylation. Finally, we discuss the latest insights and future directions concerning the diverse functions of DNA methylation in reproductive outcomes.

Reproductive health is a critical determinant of livestock productivity and economic sustainability. However, it is often compromised by infectious diseases, environmental stressors, and nutritional deficits. Phytogenic extracts—bioactive compounds derived from medicinal plants—have emerged as sustainable alternatives to synthetic antibiotics and hormones, exhibiting antimicrobial, antioxidant, and immunomodulatory properties. These extracts influence key reproductive processes such as follicular development, oocyte maturation, and endometrial health while mitigating the detrimental effects of oxidative stress and pathogenic infections. Recent findings suggest that phytogenic extract can enhance reproductive performance, improve oocyte quality, and support pregnancy outcomes. Despite the growing body of evidence, optimal application strategies and the full breadth of their biological effects remain insufficiently explored. This review focuses on the molecular mechanisms modulated by phytogenic extracts, particularly in the context of hormone regulation, immune modulation, and oxidative stress mitigation. We also identify critical knowledge gaps and propose future research directions to optimize the use of phytogenic extracts as a sustainable approach to enhancing livestock reproductive health.

Abstract mcr-10 is among the growing families of newly identified plasmid-mediated mobile colistin-resistance genes. In this study, we identified an mcr-10 gene in a seafood-borne extended-spectrum β-lactamase (ESBL)-producing Enterobacter xiangfangensis. E. xiangfangensis strain, B12-S77, was subjected to whole genome sequencing using Illumina MiSeq and Oxford Nanopore Technologies. Bioinformatic analysis was performed using tools from the Center for Genomic Epidemiology. The minimum inhibitory concentration (MIC) of 19 antibiotics was determined by the broth microdilution method. Transferability of mcr-10-carrying plasmid was investigated by the conjugation experiment. The strain exhibited a multidrug-resistant (MDR) phenotype against more than three classes of antibiotics but remained susceptible to colistin and polymyxin B. mcr-10 was identified on a fused conjugative plasmid of the IncFIB (K):FII (Yp) backbone adjacent to the XerC-type tyrosine recombinase-gene. At least one insertion sequence (IS) was identified in both the downstream and upstream regions of the xerC-mcr-10 conserved region, indicating that this region may contribute to mcr-10 mobilization or integration into the bacterial genome. The strain belonged to sequence type (ST) 143 and carried the nlpI and mrkA virulence genes, which promote fimbrial adhesion or biofilm formation in enteric bacteria. This report provides novel insights into the emergence of mcr-10 in seafood-borne bacteria, and highlights the importance of surveillance in the seafood supply chain.