Non-aureus staphylococci (NAS) are ubiquitous bacteria in livestock-associated environments where they may act as reservoirs of antimicrobial resistance (AMR) genes for pathogens such as Staphylococcus aureus. Here, we tested whether housing conditions in pig farms could influence the overall AMR-NAS burden. Two hundred and forty porcine commensal and environmental NAS isolates from three different farm types (conventional, alternative, and organic) were tested for phenotypic antimicrobial susceptibility and subjected to whole genome sequencing. Genomic data were analysed regarding species identity and AMR gene carriage. Seventeen different NAS species were identified across all farm types. In contrast to conventional farms, no AMR genes were detectable towards methicillin, aminoglycosides, and phenicols in organic farms. Additionally, AMR genes to macrolides and tetracycline were rare among NAS in organic farms, while such genes were common in conventional husbandries. No differences in AMR detection existed between farm types regarding fosfomycin, lincosamides, fusidic acid, and heavy metal resistance gene presence. The combined data show that husbandry conditions influence the occurrence of resistant and multidrug-resistant bacteria in livestock, suggesting that changing husbandry practices may be an appropriate means of limiting the spread of AMR bacteria on farms.

In the escalating battle against antimicrobial resistance, there is an urgent need to discover and investigate new antibiotic strategies. Bacteriophages are untapped reservoirs of such potential antimicrobials. This study focused on Hypothetical Proteins of Unknown Function (HPUFs) from a Staphylococcus phage Stab21. We examined its HPUFs for bactericidal activity against E. coli using a Next Generation Sequencing (NGS)-based approach. Among the 96 HPUFs examined, 5 demonstrated cross-species toxicity towards E. coli, suggesting the presence of shared molecular targets between E. coli and S. aureus. One toxic antibacterial HPUF (toxHPUF) was found to share homology with a homing endonuclease. The implications of these findings are profound, particularly given the potential broad applicability of these bactericidal agents. This study confirms the efficacy of NGS in streamlining the screening process of toxHPUFs, contributes significantly to the ongoing exploration of phage biology, and offers promises in the search for potent antimicrobial agents.

The molecular effects involved in the cellular response to ultraviolet A1 (UVA1) exposures in human skin are incompletely understood. We examined the molecular mechanisms underlying the physiological effects of low-dose UVA1 exposures in human skin in vivo by observing especially the contribution of diurnal preference and circadian clock-related genes and proteins. Healthy volunteers (n = 21) were exposed to a cumulative dose of 30 J/cm² of UVA1 (340-400 nm) or 0.42 J/cm² of violet light (390-440 nm, n = 20). Immunohistochemistry, transcriptomics, real-time quantitative PCR (RT-qPCR), gene enrichment analyses, and cellular deconvolution were performed from buttock skin samples at the start and after three days of consecutive morning exposures. UVA1 exposures significantly increased CRY2 and P53 protein staining in the IHC and yielded 16 differentially expressed genes (DEGs) involved in melanogenesis (Pmel, Tyr, Tyrp1), cytotoxic protection (Aldh3a2/a1, Cdk7, Nampt, Bcl2a1, Ackr4, Rpa3, Ube2q2) and circadian rhythm (Csnk1e, Nampt) in the skin compared to unexposed skin samples. RT-qPCR was performed for Aldh3a1, Aldh3a2, Tyr, Tyrp1 and Nampt to strengthen the transcriptomic results. No DEGs were found when exploring the underlying adipose tissue or the violet light-exposed group. In cellular deconvolution analysis, the fraction of eosinophils and M0 macrophages was increased after UVA1 exposures, with M0 macrophages especially among morning-types. Low-dose UVA1 exposures caused changes in gene expression, P53 and CRY2 protein production, and cell type fractions in the skin, but the effects did not reach the subcutaneous adipose tissue. Since the solar UVR dominates in UVA, it is essential to continue to protect the skin from harmful solar agents, regardless of the diurnal preference.