Effect of Chitosan Microparticles on the Uterine Microbiome of Dairy Cows with Metritis.

The objective of this study was to evaluate the effect of chitosan microparticles on the uterine microbiome of cows with metritis. Dairy cows with metritis (n = 89) were assigned to 1 of 3 treatments: chitosan microparticles (n = 21), in which the cows received an intrauterine infusion of chitosan microparticles at metritis diagnosis (day 0), day 2, and day 4; ceftiofur (n = 25), in which the cows received a subcutaneous injection of ceftiofur on day 0 and day 3; and no intrauterine or subcutaneous treatment (n = 23). Nonmetritic cows (n = 20) were healthy cows matched with cows with metritis by the number of days postpartum at metritis diagnosis. Uterine swab samples collected on days 0, 3, 6, 9, and 12 were used for 16S rRNA gene sequencing and 16S RNA gene copy number quantification by quantitative PCR. Principal-coordinate analysis showed that the microbiome of the ceftiofur-treated and metritic untreated groups progressed toward that of the nonmetritic group by day 3, whereas that of the chitosan microparticle-treated group remained unchanged. The differences on day 3 were mainly due to a greater relative abundance of Fusobacteria, particularly Fusobacterium, in the chitosan microparticle-treated group than in the ceftiofur-treated and metritic untreated groups. Furthermore, the microbiome of the ceftiofur-treated group became similar to that of the nonmetritic group by day 9, whereas the microbiome of the chitosan microparticle-treated and metritic untreated groups became similar to that of the nonmetritic group only by day 12. The total bacterial 16S rRNA gene counts in the chitosan microparticle-treated group were greater than those in the metritic untreated controls on days 6 and 9, whereas the ceftiofur treatment group was the only group in which the total bacterial 16S rRNA gene count became similar to that in the nonmetritic group by day 12. In summary, chitosan microparticles slowed the progression of the uterine microbiome toward a healthy state, whereas ceftiofur hastened the progression toward a healthy state.IMPORTANCE Third-generation cephalosporins, such as ceftiofur, are commonly used to treat metritis in dairy cows. Chitosan microparticles has been shown to have a broad spectrum of activity in vitro and to be effective against uterine pathogens in vivo; therefore, they have been hailed as a possible alternative to traditional antibiotics. Nonetheless, in the present study, we saw that chitosan microparticle treatment slowed the progression of the uterine microbiome of cows with metritis toward a healthy state, whereas ceftiofur treatment hastened the progression toward a healthy state. Given the lack of an effective alternative to traditional antibiotics and an increased concern about antimicrobial resistance, a greater effort should be devoted to the prevention of metritis in dairy cows.

Essential role of toll-like receptor 4 in Acinetobacter baumannii-induced immune responses in immune cells.

TLR4 is a membrane sensor for lipopolysaccharide (LPS), a major cell wall component of gram-negative bacteria. In this study, we investigated the role of TLR4 on innate immune responses in immune cells against Acinetobacter baumannii. Bone marrow-derived macrophages (BMDMs) and dendritic cells (BMDCs) were isolated from WT and TLR4-deficient mice and infected with A. baumannii ATCC 15150. ELISA assay revealed that the production of IL-6 and TNF-α by A. baumannii was impaired in TLR4-deficient macrophages. However, absence of TLR2 did not affect A. baumannii-induced cytokines production in BMDMs. In addition, TLR4 was required for the optimal production of IL-6, TNF-α, and IL-12 in BMDCs in response to A. baumannii. Western blot analysis showed that A. baumannii leads to the activation of NF-κB and MAPKs (p38, ERK, and JNK) in macrophages via TLR4-dependent pathway. mRNA expression of iNOS and NO production was elicited in WT BMDMs in response to A. baumannii, which was abolished in TLR4-deficienct cells. Bacterial killing ability against A. baumannii was impaired in TLR4-deficient BMDMs. In addition, A. baumannii induced apoptosis in BMDMs via TLR4-independent pathway. Our results demonstrate that TLR4 is essential for initiating innate immune response of macrophages against A. baumannii infection.

Complete Genome Sequence of an Escherichia coli O157:H7 Strain Isolated from a Super-Shedder Steer.

We report here the complete genome sequence ofEscherichia coliO157:H7 strain JEONG-1266 isolated from a super- shedder steer in northwest Florida. Cattle are considered a primary reservoir ofE. coliO157:H7, and those cattle that excrete this pathogen in their feces at levels ≥10(4) CFU/g are known as super-shedders.

In vitro and in vivo growth inhibition of prostate cancer by the small molecule imiquimod.

Prostate cancer is the second leading cause of cancer death in men worldwide. In the present study, we examined in vitro and in vivo antitumor effect of the small molecule imiquimod, also known as a TLR7 agonist, against prostate cancer. Imiquimod inhibited the growth of mouse (TRAMP­C2) and human (PC-3) prostate cancer cells. Treatment with imiquimod induced cell cycle arrest at the G2/M phase in TRMPA-C2 cells, confirmed by the changes of G2/M checkpoint regulators such as reduction of cyclin B1 expression and increase of phospho-CDC2 and p21 in TRAMP-C2 cells treated with imiquimod. Flow cytometry and western blot analysis revealed that imiquimod induced direct apoptosis in TRAMP-C2 cells via a mitochondrial­dependent pathway. Intratumoral injection with imiquimod reduced significantly tumor growth and increased apoptotic cells in mice subcutaneously implanted with TRAMP-C2 cells. Our results indicate that imiquimod can be an alternative therapeutic for locally generated prostate cancer.