Chronic inflammation can cause oviduct mucosal damage and immune dysfunction, leading to infertility, early pregnancy loss, ectopic pregnancy, tumors, and a decrease in reproductive capacities in female animals. Estrogen can suppress immune responses in different tissues and oviducts, and regulate the oviduct immune balance; however, the underlying mechanisms remain unclear. The objective of this study was to explore the mechanism of estrogen-regulated oviduct mucosal immunity and discover new estrogen targets for regulating oviduct mucosal immune homeostasis. Sheep oviduct epithelial cells (SOECs) were treated with 17-β estradiol (E2). Transcriptome sequencing and analysis showed differentially expressed S100 calcium-binding protein A (S100A) genes that may participate in the oviduct mucosa immunoregulation of estrogen. Quantitative polymerase chain reaction and immunocytochemistry analysis showed thatS100A8expression changed dynamically in E2-treated SOECs and peaked after 7 h of treatment. Estrogen nuclear receptors and G protein-coupled membrane receptors promoted E2-dependentS100A8upregulation. TheS100A8gene was disrupted using the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 method. Levels of inflammatory factors interleukin (IL)-1β and IL-4 were significantly upregulated inS100A8-knockdown SOECs, whereas those of the anti-inflammatory factor IL-10 was downregulated. Following S100A8 knockdown in SOECs treated with E2 for 7 h, IL-10 levels increased significantly. Estrogen affected oviduct mucosa immune function and dynamically regulated S100A8 in SOECs. S100A8 knockdown caused an excessive immune response, indicating that S100A8 is beneficial for maintaining immune homeostasis in the oviduct mucosa. Moreover, estrogen can compensate for the effect of S100A8 knockdown by upregulating IL-10.

Tigecycline is often used as a last-resort antibiotic to combat multidrug-resistant Klebsiella pneumoniae (MDR-KP). However, reports of tigecycline resistance are increasing. Thirty-two tigecycline-insensitive K. pneumoniae (TIKP) strains were detected among 152 MDR-KP isolates obtained from a tertiary hospital in China (21%). Whole-genome sequencing (Illumina NovaSeq 6000) revealed that these 32 TIKP isolates carried 119–127 virulence genes, 38–63 resistance genes, and 21 distinct sequence types (STs), including a novel ST (8597), together with 102,632 single-nucleotide polymorphisms. The predominant plasmid types included IncFIB(K) (10/32), IncFII(K) (11/32), IncR (11/32), RepB (13/32), and IncHI1B(pNDM-MAR) (12/32). The biofilm formation and serum resistance of the four strains were tested with a Galleria mellonella infection assay and whole-genome sequencing (PacBio platform). Among these strains, strain 10 showed strong biofilm formation and the strongest serum resistance. Compared with the other strains, it carried the most plasmids, and its chromosomes and plasmids harbored numerous resistance genes and contained more tigecycline resistance genes. These findings demonstrate the complex genetic features and potential transmission mechanisms of TIKP isolates. IMPORTANCE: Our study revealed a high proportion (21%) of tigecycline-insensitive K. pneumoniae (TIKP) strains. We further characterized these TIKP isolates phenotypically and genomically, confirming the presence of highly virulent multidrug-resistant (MDR) strains. We discovered a novel allele (phoE 813) and a novel ST (8597). Our findings are significant because phenotypic analysis of TIKP allows clear determination of the level of tigecycline resistance (TRKP), which aids in optimizing antibiotic therapy and supports more rational clinical drug use. In addition, the plasmid-mediated resistance genes (e.g., the concurrent presence of both mcr-8 and tmexCD–toprJ in strain 10 in this study) may spread through the environmental–animal–human transmission chain. These results provide valuable insights for developing strategies to monitor and control the spread of TIKP.