Comparative genomic analyses of Klebsiella pneumoniae K57 capsule serotypes isolated from bovine mastitis in China.

Klebsiella pneumoniae can cause severe clinical mastitis in dairy cows, with K. pneumoniae type K57 (K57-KP) being the most common capsular serotype. To identify virulence factors and antimicrobial-resistance (AMR) genes of K57-KP with varying virulence, Galleria mellonella (greater wax moth) larvae were infected as a screening model to characterize virulence of 90 K57-KP strains, with 10 and 11 strains defined as virulent or attenuated, respectively, based on larval survival rates. Next, virulence of these 21 isolates was subsequently confirmed in adhesion and lactate dehydrogenase release assays, using bovine mammary epithelial cells cultured in vitro. Finally, genes associated with virulence and AMR were characterize with whole-genome sequencing. These 21 K57-KP strains were designated into 16 sequence types based on multi-locus sequence typing and allocated in phylogenetic analysis based on single nucleotide polymorphisms. We found great genetic diversity among isolates. In addition, adhesion-associated genes (e.g., fimA, sfaA, and focA) aminoglycoside-resistance genes (aph(6)-Id, strAB) were associated with virulence. This study provided new knowledge regarding virulence of K57-KP associated with bovine mastitis, which may inform development of novel diagnostic tools and prevention strategies for bovine mastitis.

11 cases of peritoneal dialysis catheter penetrating into the intestinal cavity: case series.

The penetration of a peritoneal dialysis catheter into the intestinal cavity is a clinically rare complication. In the present retrospective clinical case series, 11 patients with uraemia who received continuous ambulatory peritoneal dialysis and attended hospital between 2019 and 2023 are described. The median patient age was 61.91 ± 11.33 years. All patients had previously experienced peritoneal dialysis-related peritonitis and were clinically cured by infusing sensitive antibiotics into the abdominal cavity. Colonoscopy was utilised to locate the penetrating catheter and close the perforation with a titanium clip once the catheter had been removed via an external approach. Following a 2-4-week fast, the perforations healed in all 11 patients. The present authors' experience illustrates that directly removing the catheter and clamping the perforation opening under the guidance of colonoscopy is simple to operate with few complications compared with traditional open surgery.

Immunoprotective efficacy of 3 Klebsiella pneumoniae type I fimbriae proteins in a murine model.

Klebsiella pneumoniae is a primary cause of clinical mastitis in dairy cows, with prevention being crucial, as treatments often fail due to antimicrobial resistance. Recent studies identified type I fimbrial antigens of K. pneumoniae as promising vaccine candidates, but there are limited research data. In this study, 3 fimbriae genes (fimA, fimC and fimG) were cloned and recombinantly expressed in Escherichia coli and their protective efficacy against K. pneumoniae evaluated in a mouse model. All 3 recombinant fimbriae proteins elicited strong humoral immune responses in mice, significantly increasing IgG, IgG1 and IgG2a. Notably, using a model of mice challenged with an intraperitoneal injection of bacteria, FimG significantly reduced bacterial loads in the spleen and lung, whereas FimA and FimC had limited protection for these organs. Either active or passive immunization with FimG produced substantial protective effects in mice challenged with K. pneumoniae LD100; in contrast, the mortality rate in the FimA-immunized group was similar to that of the control group, whereas FimC had weak protection. We concluded that the FimG recombinant protein vaccine had a favorable protective effect, with potential for immunization against K. pneumoniae mastitis.

Biological and genomic characterization of 4 novel bacteriophages isolated from sewage or the environment using non-aureus Staphylococci strains.

Non-aureus staphylococci (NAS) are an essential group of bacteria causing antimicrobial resistant intramammary infections in livestock, particularly dairy cows. Therefore, bacteriophages emerge as a potent bactericidal agent for NAS mastitis. This study aimed to obtain NAS-specific bacteriophages using bacterial strains isolated from cows with mastitis, subsequently evaluating their morphological, genomic, and lytic characteristics. Four distinct NAS bacteriophages were recovered from sewage or the environment of Chinese dairy farms; PT1-1, PT94, and PT1-9 were isolated using Staphylococcus chromogenes and PT1-4 using Staphylococcus gallinarum. Both PT1-1 (24/54, 44 %) and PT94 (28/54, 52 %) had broader lysis than PT1-4 (3/54, 6 %) and PT1-9 (10/54, 19 %), but PT1-4 and PT1-9 achieved cross-species lysis. All bacteriophages had a short latency period and good environmental tolerance, including surviving at pH=4-10 and at 30-60℃. Except for PT1-9, all bacteriophages had excellent bactericidal efficacy within 5 h of co-culture with host bacteria in vitro at various multiplicity of infection (MOIs). Based on whole genome sequencing, average nucleotide identity (ANI) analysis of PT1-1 and PT94 can be classified as the same species, consistent with whole-genome synteny analysis. Although motifs shared by the 4 bacteriophages differed little from those of other bacteriophages, a phylogenetic tree based on functional proteins indicated their novelty. Moreover, based on whole genome comparisons, we inferred that cross-species lysis of bacteriophage may be related to the presence of "phage tail fiber." In conclusion 4 novel NAS bacteriophages were isolated; they had good biological properties and unique genomes, with potential for NAS mastitis therapy.

Alternatives to antibiotics for treatment of mastitis in dairy cows.

Mastitis is considered the costliest disease on dairy farms and also adversely affects animal welfare. As treatment (and to a lesser extent prevention) of mastitis rely heavily on antibiotics, there are increasing concerns in veterinary and human medicine regarding development of antimicrobial resistance. Furthermore, with genes conferring resistance being capable of transfer to heterologous strains, reducing resistance in strains of animal origin should have positive impacts on humans. This article briefly reviews potential roles of non-steroidal anti-inflammatory drugs (NSAIDs), herbal medicines, antimicrobial peptides (AMPs), bacteriophages and their lytic enzymes, vaccination and other emerging therapies for prevention and treatment of mastitis in dairy cows. Although many of these approaches currently lack proven therapeutic efficacy, at least some may gradually replace antibiotics, especially as drug-resistant bacteria are proliferating globally.

Current Research Trends in Traditional Chinese Medicine Formula: A Bibliometric Review from 2000 to 2016.

BACKGROUND: Traditional Chinese Medicine Formula (TCMF) study has been recognized widely by medical scientists around the world. However, few researchers have analyzed and summarized the rapid growth of academic articles of TCMF published in English. The primary aim of this work was to assess the outcome of these research outputs in the TCMF field from 2000 to 2016 and to evaluate the situation and tendency. METHODS: Research datasets were acquired from the Web of Science database, which includes all academic articles published from 2000 to 2016; articles were tracked by the keywords "Traditional Chinese Medicine", "Traditional Chinese Medicine Formula", and "Chinese herb formula". Moreover, visualization software CiteSpace V was used to analyze and generate visualization knowledge maps. RESULTS: In total, 26,917 articles appeared in the Web of Science database, and only 2,621 publications met requirement based on reading the abstract or full text. The annual publications total, list of journals, research interests, list of medicine names, disease types, and the top 20 cited articles were given in this research paper. In addition, we compared the research of Japan and Korea TCMF, in the appendix. CONCLUSION: This review demonstrates that increasingly more researchers have interest in the TCMF and TCMF has great significant advantages over other areas of focus. However, these publications were published rarely in top academic journals and most best-quality papers have bias toward medical analysis rather than pharmacology. To make a breakthrough in TCMF field, further investigation is required to place emphasis on the deepening study of the mechanism of related TCMF.

Injectable hydrogels based on glycyrrhizin, alginate, and calcium for three-dimensional cell culture in liver tissue engineering.

Injectable hydrogels have been paid more attentions on cell therapy and tissue regeneration resulting from the applications in minimally invasive surgical procedures with ease of handling and complete filling of defect area. Here, a biodegradable and injectable in situ hydrogel formed by glycyrrhizin (GL), alginate (Alg), and calcium (Ca) was developed for three-dimensional (3D) cell culture. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM) and rheology analysis were performed to characterize GL-Alg-Ca hydrogel and evaluate its formation mechanism, properties, and morphology. The biocompatibility of hydrogel was investigated by cell viability, morphology, and liver specific functions. The results of DSC, XRD, and rheology suggested that hydrogel was homogenous complex with stable structure and well viscoelasticity. Human hepatoma HepG2 cells cultured in hydrogels showed well morphology. Compared with the control group, cells in hydrogels showed good biocompatibility, and could maintain the viability, proliferation and liver function for longer periods of time. Furthermore, the hydrogel improved the mRNA expression of cytochrome P450, which were key enzyme to the metabolization of hepatocytes. The GL-Alg-Ca hydrogel could be a potential 3D cells culture system for liver tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3292-3302, 2018.