Jun Liu

The continued rise in carbapenem-resistant Enterobacter cloacae (CREC) detections indicates that current control measures are insufficient, potentially due

Syngnathoides biaculeatus , a potential functional food from marine sources, was found to enhance nonspecific immunity, but its functional ingredients have rarely been reported. Therefore, this study focused on the preparation and physicochemical properties of its water-soluble natural ingredients with their immunomodulatory activities and potential mechanisms. Firstly, we optimized the extraction method of glycoproteins from S. biaculeatus and prepared the crude glycoprotein SYB, from which the fraction glycoprotein SYB-1 was further purified. The carbohydrates of SYB-1 were 8.46% comprising mannose, glucose, and galactose, with an average molecular weight of 9.423 kDa. Amino acid analysis demonstrated that its major amino acids are glycine, glutamic acid, aspartic acid, and proline, with a total amino acid content of 88.81%. Furthermore, SYB-1 could significantly increase the cell viability of macrophages, and promote the release of NO, TNF- α , and IL-6. Metabolomics revealed that it was associated with arachidonic acid metabolism. The CYP450 enzyme family members and PTGS2 may be key targets for the regulatory role. These results suggested that the glycoprotein of S. biaculeatus may be an attractive functional food supplement from natural sources for immunocompromised populations. Graphical Abstract

The Corona Virus Disease 2019 (COVID-19) pandemic has introduced complex challenges in resistance and transmission. During the COVID-19 pandemic, increased antibiotic use, interruptions in healthcare services, and complex infections in patients can all promote the emergence and spread of drug-resistant bacteria. However, detailed investigations into the characteristics of carbapenemase-encoding genes (CEGs) in carbapenem-resistant Enterobacter cloacae (CREC) and the alterations in their transmission dynamics during the pandemic remain scarce. This study analyzed 54 CREC strains collected from eight teaching hospitals in Guangdong Province, China, between December 2022 and June 2024. The variable temperature Sodium Dodecyl Sulfate (SDS) plasmid elimination method and PCR were used to analyze the samples. The positive rate of CEGs was 85.19% (46/54). Among the 54 CREC isolates, 33.33% (18/54) carried the blaNDM−1 gene on both chromosomes and plasmids. A total of 46.30% (25/54) of the isolates had the blaNDM−1 gene exclusively on plasmids. Additionally, 3.70% (2/54) of the isolates harbored only the blaIMP gene on plasmids. Finally, 1.85% (1/54) of the isolates contained both the blaNDM−1 gene and blaKPC−2 gene on plasmids. The broth microdilution method showed that the resistance rate of CEG-positive group to imipenem, cefepime, gentamicin, ceftazidime/avibactam, ciprofloxacin and levofloxacin were significantly higher than those of CEG-Negative group (P<0.05). Plasmid conjugation experiments and PCR analysis revealed a 95.65% (44/46) success rate for the transfer of CEGs. Among these, the success rates for the blaNDM−1, blaIMP, and blaKPC−2 genes were 95.45% (42/44), 100.00% (2/2) and 0% (0/1) respectively. Six types of mobile genetic elements were identified, with ISEcp1 being the most prevalent (87.04%, 47/54). CREC carrying four types of mobile genetic elements simultaneously was the most prevalent (40.74%, 22/54). ERIC-PCR and NTSYS software categorized the 54 CREC strains into 17 genotypes, with type E and type G showing the highest prevalence (both of them 20.37%, 11/54), originating from different departments in five hospitals. Among the type E isolates, 3.70% (2/54) strains shared a Dice coefficient of 100%. The epidemiology of CEG shows that the detection rates of men, elderly people, respiratory medicine, and sputum samples are the highest in gender, age group, clinical department, and specimen category, accounting for 64.81% (35/54), 72.22% (39/54), 20.37% (11/54) and 33.33% (18/54), respectively. CREC plasmids and chromosomes frequently harbor CEGs, with the blaNDM−1 gene being a predominant example, particularly when located on plasmids. CEG-positive strains demonstrated significant levels of multidrug resistance. Furthermore, CEGs displayed a notable capacity for both horizontal and vertical dissemination. Higher detection frequencies of CEGs were identified in male patients, elderly individuals, within respiratory medicine contexts, and in sputum samples.

Fungi Fusarium proliferatum and the toxins it produces are hazardous to agricultural plants, animals, and human health. The signaling pathways and biotargets of F. proliferatum triggered by MNQ were confirmed in this work.

Methicillin-resistant Staphylococcus aureus (MRSA) is highly concerning as a principal infection pathogen. The investigation of higher effective natural anti-MRSA agents from marine Streptomyces parvulus has led to the isolation of actinomycin D, that showed potential anti-MRSA activity with MIC and MBC values of 1 and 8 μg/mL, respectively. Proteomics-metabolomics analysis further demonstrated a total of 261 differential proteins and 144 differential metabolites induced by actinomycin D in MRSA, and the co-mapped correlation network of omics, indicated that actinomycin D induced the metabolism pathway of producing the antibiotic sensitivity in MRSA. Furthermore, the mRNA expression levels of the genes acnA, ebpS, clfA, icd, and gpmA related to the key differential proteins were down-regulated measured by qRT-PCR. Molecular docking predicted that actinomycin D was bound to the targets of the two key differential proteins AcnA and Icd by hydrogen bonds and interacted with multiple amino acid residues of the proteins. Thus, these findings will provide a basic understanding to further investigation of actinomycin D as a potential anti-MRSA agent.

Staphylococcus aureus (S. aureus) is a common pathogen that causes various serious diseases, including chronic infections. Discovering new antibacterial agents is an important aspect of the pharmaceutical field because of the lack of effective antibacterial drugs. In our research, we found that one anti-S. aureus substance is actinomycin D, originating from Streptomyces parvulus (S. parvulus); then, we further focused on the anti-S. aureus ability and the omics profile of S. aureus in response to actinomycin D. The results revealed that actinomycin D had a significant inhibitory activity on S. aureus with a minimum inhibitory concentration (MIC) of 2 μg/mL and a minimum bactericidal concentration (MBC) of 64 μg/mL. Bacterial reactive oxygen species (ROS) increased 3.5-fold upon treatment with actinomycin D, as was measured with the oxidation-sensitive fluorescent probe DCFH-DA, and H₂O₂ increased 3.5 times with treatment by actinomycin D. Proteomics and metabolomics, respectively, identified differentially expressed proteins in control and treatment groups, and the co-mapped correlation network of proteomics and metabolomics annotated five major pathways that were potentially related to disrupting the energy metabolism and oxidative stress of S. aureus. All findings contributed to providing new insight into the mechanisms of the anti-S. aureus effects of actinomycin D originating from S. parvulus.

In this study, a homogenous polysaccharide (FSP), with an average molecular weight of 9.08 × 10⁴ Da, was isolated from Forsythia suspense and its antibacterial potential against Enterobacter cloacae producing SHV‐12 ESBL was investigated. Growth kinetics, in vitro competition and biofilm formation experiments demonstrated that SHV‐12 ESBL contributed to a fitness benefit to E cloacae strain. The antibacterial activity of FSP (2.5, 5.0 and 10.0 μg/mL) was tested against E cloacae bearing SHV‐12 ESBL gene using bacterial sensitivity, agar bioassay and agar well diffusion assays. It was found that the addition of FSP demonstrated potent antibacterial activities against this bacterial as showed by the decrease of bacterial growth and the increase of the inhibition zone diameter. Furthermore, SHV‐12 ESBL gene expression was decreased in E cloacae strain following different FSP treatment in a concentration‐dependent manner. In conclusion, these data showed that FSP exhibited potent good antibacterial activity against E cloacae producing SHV‐12 ESBL via inhibition of SHV‐12 ESBL gene expression, which may promote the development of novel natural antibacterial agents to treat infections caused by this drug‐resistant bacterial pathogen.

Some oligosaccharides are regarded as biological constituents with benefits to human health in an indirect way.

Unsaturated fatty acids (UFAs) are an important category of monounsaturated and polyunsaturated fatty acids with nutritional properties.