Assessment of probiotic Bacillus velezensis supplementation to reduce Campylobacter jejuni colonization in chickens.

Campylobacter jejuni continues to be a major public health issue worldwide. Poultry are recognized as the main reservoir for this foodborne pathogen. Implementing measures to decrease C. jejuni colonization on farms has been regarded as the most effective strategy to control the incidence of campylobacteriosis. The probiotics supplementation has been regarded as an attractive approach against C. jejuni in chickens. Here the inhibitory effects of one probiotic B. velezensis isolate CAU277 against C. jejuni was evaluated in vitro and in vivo. The in vitro antimicrobial activity showed that the supernatant of B. velezensis exhibited the most pronounced inhibitory effects on Campylobacter strains compared to other bacterial species. When co-cultured with B. velezensis, the growth of C. jejuni reduced significantly from 7.46 log10 CFU/mL (24 h) to 1.02 log10 CFU/mL (48 h). Further, the antimicrobial activity of B. velezensis against C. jejuni remained stable under a broad range of temperature, pH, and protease treatments. The in vivo experiments demonstrated that oral administration of B. velezensis significantly reduced the colonization of C. jejuni by 2.0 log10 CFU/g of feces in chicken cecum at 15 d postinoculation. In addition, the supplementary of B. velezensis significantly increased microbial species richness and diversity in chicken ileum, especially enhanced the bacterial population of Alistipes and Christensenellaceae, and decreased the existence of Lachnoclostridium. Our study presents that B. velezensis possesses antimicrobial activities against C. jejuni and promotes microbiota diversity in chicken intestines. These findings indicate a potential to develop an effective probiotic additive to control C. jejuni infection in chicken.

Coumarin Glycosides Reverse Enterococci-Facilitated Enteric Infections.

Commensal enterococci with pathogenic potential often facilitate the growth of diverse pathogens, thereby exacerbating infections. However, there are few effective therapeutic strategies to prevent and intervene in enterococci-mediated polymicrobial infections. Here, we find that enterococci at high density drive the expansion and pathogenicity of enteric Salmonella enterica serotype Typhimurium (S. Tm). Subsequently, we show that the driving role of enterococci in such infections is counteracted by dietary coumarin glycosides in vivo. Enterococci, which are tolerant of iron-deficient environments, produce ß-glucosidases to hydrolyze coumarin glycosides into bioactive aglycones, inhibiting S. Tm growth and ameliorating the severity of S. Tm-induced symptoms by inducing iron limitation. Overall, we demonstrate that coumarin glycosides as a common diet effectively reverse enterococci-facilitated enteric infections, providing an alternative intervention to combat polymicrobial infections.

Antimicrobial resistance profiles of common mastitis pathogens on large Chinese dairy farms.

The primary objective of this study was to determine the antimicrobial resistance (AMR) profile of common mastitis pathogens on large Chinese dairy farms. A total of 673 isolates, including Staphylococcus aureus (14.41%, 97/673), coagulase-negative staphylococci (CNS, 52.30%, 352/673), Streptococcus agalactiae (5.64%, 38/673), non-agalactiae streptococci (7.42%, 50/673), Acinetobacter spp. (7.72%, 52/673), Escherichia spp. (6.39%, 43/673), and Klebsiella spp. (6.09%, 41/673), were collected from 15 large Chinese dairy farms in 12 provinces. The AMR profiles were measured using a microdilution method. Our results showed that more than 75% of Staph. aureus (87/97) and CNS (291/352) were resistant to penicillin (PEN). More than 30% of Escherichia spp. (15/43) showed resistance to ampicillin (AMP). However, less than 10% CNS and non-agalactiae streptococci showed resistance to amoxicillin/clavulanate (AMC; 1/352; 0/50), cephalexin (LEX; 1/352; 0/50), ceftiofur (EFT; 10/352; 0/50), and rifaximin (RIX; 21/352; 2/50); less than 10% Staph. aureus showed resistance to AMC (1/97), oxacillin (OX; 3/97), LEX (1/97), EFT (2/97), and RIX (2/97); less than 10% Strep. agalactiae showed resistance to PEN (3/38), AMC (0/38), LEX (0/38), EFT (0/38), and RIX (0/38); and less than 10% Escherichia spp. showed resistance to AMC (1/43) and EFT (4/43). These results suggested that most mastitis pathogens were susceptible to most antimicrobials with exceptions of Staph. aureus tested against penicillin or ampicillin and CNS against penicillin or oxacillin. To control the AMR threat in Chinese dairy farms, a nationwide surveillance program for AMR of bovine mastitis pathogens is needed.

Bacterial-derived sialidases inhibit porcine rotavirus OSU replication by interfering with the early steps of infection.

Rotavirus infections in suckling and weaning piglets cause severe dehydration and death, resulting in significant economic losses in the pig breeding industry. With the continuous emergence of porcine rotavirus (PoRV) variants and poor vaccine cross-protection among various genotypes, there is an urgent need to develop alternative strategies such as seeking effective antiviral products from nature, microbial metabolites and virus-host protein interaction. Sialidases play a crucial role in various physiopathological processes and offer a promising target for developing antivirus drugs. However, the effect of bacterial-derived sialidases on the infection of PoRVs remains largely unknown. Herein, we investigated the impact of bacterial-derived sialidases (sialidase Cp and Vc) on PoRV strain OSU(Group A) infection, using differentiated epithelial monkey kidney cells (MA104) as a model. Our results indicated that the pretreatment of MA104 with exogenous sialidases effectively suppressed PoRV OSU in a concentration-dependent manner. Notably, even at a concentration of 0.01 µU/mL, sialidases significantly inhibited the virus (MOI = 0.01). Meanwhile, we found that sialidase Vc pretreatment sharply reduced the binding rate of PoRV OSU. Last, we demonstrated that PoRV OSU might recognize α-2,3-linked sialic acid as the primary attachment factor in MA104. Our findings provide new insights into the underlying mechanism of PoRV OSU infections, shedding lights on the development of alternative antivirus approaches based on bacteria-virus interaction.

Effect of waiting time for radiotherapy after last induction chemotherapy on prognosis of locally advanced nasopharyngeal carcinoma.

BACKGROUND: The effect of radiotherapy waiting time after last induction chemotherapy (IC-RT) on prognosis of patients with locally advanced nasopharyngeal carcinoma (LANPC) needs further discussion. METHODS: Three hundred and six patients with LANPC diagnosed pathologically by induction chemotherapy (IC) and radiotherapy (RT) from 2013 to 2018 were selected for this study. RESULTS: The IC-RT was a risk factor for the post-treatment progression of LANPC (OR = 1.017 95%CI: 1.003-1.031), For patients with LANPC, the IC-RT > 40 days significantly reduced 5-year PFS (70% vs. 55%; p = 0.0012), 5-year OS (84% vs. 73%; p = 0.028), 5-year DMFS (80% vs. 66%; p = 0.003), 5-year LRFS (77% vs. 67%; p = 0.012). Indicating that patients with stage IVa who IC-RT > 40 days were found to be a significant predictor of aggravated PFS (HR = 2.69; 95%CI: 1.57-4.6), OS (HR = 2.55; 95%CI: 1.29-5.03), DMFS (HR = 3.07; 95%CI: 1.64-5.76) and LRFS (HR = 2.26; 95%CI: 1.21-4.21). CONCLUSION: The prognosis of patients will be adversely affected if the IC-RT exceeds 40 days, especially for stage IVa patients.

Data-driven classification of left atrial morphology and its predictive impact on atrial fibrillation catheter ablation.

INTRODUCTION: Various left atrial (LA) anatomical structures are correlated with postablative recurrence for atrial fibrillation (AF) patients. Comprehensively integrating anatomical structures, digitizing them, and implementing in-depth analysis, which may supply new insights, are needed. Thus, we aim to establish an interpretable model to identify AF patients' phenotypes according to LA anatomical morphology, using machine learning techniques. METHODS AND RESULTS: Five hundred and nine AF patients underwent first ablation treatment in three centers were included and were followed-up for postablative recurrent atrial arrhythmias. Data from 369 patients were regarded as training set, while data from another 140 patients, collected from different centers, were used as validation set. We manually measured 57 morphological parameters on enhanced computed tomography with three-dimensional reconstruction technique and implemented unsupervised learning accordingly. Three morphological groups were identified, with distinct prognosis according to Kaplan-Meier estimator (p < .001). Multivariable Cox model revealed that morphological grouping were independent predictors of 1-year recurrence (Group 1: HR = 3.00, 95% CI: 1.51-5.95, p = .002; Group 2: HR = 4.68, 95% CI: 2.40-9.11, p < .001; Group 3 as reference). Furthermore, external validation consistently demonstrated our findings. CONCLUSIONS: Our study illustrated the feasibility of employing unsupervised learning for the classification of LA morphology. By utilizing morphological grouping, we can effectively identify individuals at different risks of postablative recurrence and thereby assist in clinical decision-making.

Enterococci facilitate polymicrobial infections.

Enterococci are ubiquitous members of the gut microbiota in human beings and animals and are among the most important nosocomial organisms. Due to their opportunistic pathogenicity, enterococci are referred to as pathobionts and play decisive roles in a diverse array of polymicrobial infections. Enterococci can promote the colonization, pathogenesis, and persistence of various pathogens, compromise the efficacy of drugs, and pose a severe threat to public health. Most current treatments tend to focus on the sole pathogenic bacteria, with insufficient attention to the driving role of enterococci. In this review, we summarize the characteristics of enterococci in infections, the factors facilitating their outgrowth, as well as the sites and types of enterococci-associated polymicrobial infections. We present an overview of the underlying mechanisms of enterococci-mediated pathogenesis in polymicrobial infections. Furthermore, we discuss alternative strategies and potential intervention approaches to restrict such infections, shedding light on the discovery and development of new therapies against polymicrobial infections.

Postantibiotic leukocyte enhancement-mediated reduction of intracellular bacteria by macrophages.

INTRODUCTION: Potentiation of the bactericidal activities of leukocytes, including macrophages, upon antibacterial agent administration has been observed for several decades and is summarized as the postantibiotic leukocyte enhancement (PALE) theory. Antibiotics-induced bacterial sensitization to leukocytes is commonly recognized as the mechanism of PALE. However, the degree of sensitization drastically varies with antibiotic classes, and little is known about whether and how the potentiation of leukocytes contributes to PALE. OBJECTIVES: In this study, we aim to develop a mechanistic understanding of PALE by investigating the immunoregulation of traditional antibiotics on macrophages. METHODS: Interaction models between bacteria and macrophages were constructed to identify the effects of different antibiotics on the bactericidal activities of macrophages. Oxygen consumption rate, expression of oxidases, and antioxidants were then measured to evaluate the effects of fluoroquinolones (FQs) on the oxidative stress of macrophages. Furthermore, the modulation in endoplasmic reticulum stress and inflammation upon antibiotic treatment was detected to analyze the mechanisms. At last, the peritoneal infection model was utilized to verify the PALE in vivo. RESULTS: Enrofloxacin significantly reduced the intracellular burden of diverse bacterial pathogens through promoting the accumulation of reactive oxygen species (ROS). The upregulated oxidative response accordingly reprograms the electron transport chain with decreased production of antioxidant enzymes to reduce internalized pathogens. Additionally, enrofloxacin modulated the expression and spatiotemporal localization of myeloperoxidase (MPO) to facilitate ROS accumulation to target invaded bacteria and downregulated inflammatory response to alleviate cellular injury. CONCLUSION: Our findings demonstrate the crucial role of leukocytes in PALE, shedding light on the development of new host-directed antibacterial therapies and the design of rational dosage regimens.

Discovery of adjuvants with antibacterial potentiation activity against carbapenemase-producing Enterobacterales based on in silico virtual screening.

Bacterial multi-drug resistance has become a concern worldwide, especially after the emergence of carbapenemases. Adjuvants with antibacterial potentiation activity can resensitise drug-resistant strains to carbapenems. However, only a few adjuvants with antibacterial potentiation activity are currently available in clinical practice. Here, we first docked the library containing more than 30,000 small molecules to carbapenemases including Klebsiella pneumoniae carbapenemase 2 (KPC-2) and New Delhi metallo-ß-lactamase-5 (NDM-5), through in silico virtual screening to obtain lead compounds against carbapenemase-producing Enterobacterales. Meanwhile, the in vitro antibacterial potentiation assays revealed that ibandronate, azacytidine, ribostamycin sulfate and cidofovir exhibited synergistic or additive activity in the presence of meropenem, with good biocompatibility based on red blood cell hemolysis and cell viability tests. Furthermore, the combination of meropenem and azacytidine showed high efficacy in a mouse sepsis model infected with an NDM-5-producing clinical strain, with a 100% survival rate, decreased bacterial burden and alleviated pathological deterioration. These results suggest that the virtual screening is a promising strategy to identify new antibiotic adjuvants targeting carbapenemase-producing Enterobacterales.

An integration-free iPSC line ZZUNEUi029-A derived from peripheral blood mononuclear cells of a patient with familial hypercholesterolemia carrying a mutation in LDLR gene.

Familial hypercholesterolemia is a hereditary disorder that causes severely elevated low-density lipoprotein levels, which can lead to an increased risk for premature cardiovascular disease. Mutations in the LDLR gene are the most common cause of familial hypercholesterolemia. In this study, we report the generation of ZZUNEUi029-A, a human induced pluripotent stem cell line (hiPSC) from a male patient with c. 622 G â†’ A in LDLR gene using non-integrative Sendai viral reprogramming technology. This cell line expressed pluripotency markers, had a normal male karyotype (46XY) and maintained the ability to differentiate into the three germ layers in vitro.

Diphenyl Ether Derivative Rhexocerins and Rhexocercosporins from the Endophytic Fungus Rhexocercosporidium sp. Dzf14 Active against Gram-Positive Bacteria with Multidrug-Resistance.

Ten new diphenyl ether polyketides, including rhexocerins A-D (1-4) and rhexocercosporins A-F (5-10), together with three known congeners (11-13), were isolated from the endophytic fungus Rhexocercosporidium sp. Dzf14 obtained from Dioscorea zingiberensis. Their structures were elucidated by analysis of NMR and HRESIMS data, and their absolute configurations were determined by quantum chemical ECD calculations and X-ray crystallography. Compounds 1-4 featured an unprecedented tetracyclic carbon skeleton (6/7/5/6). Among them, compounds 1 and 5-9 showed antibacterial activities against methicillin-resistant S. aureus T144 and vancomycin-resistant E. faecalis 10.

In Situ Neutralization and Detoxification of LPS to Attenuate Hyperinflammation.

Hyperinflammation elicited by lipopolysaccharide (LPS) that derives from multidrug-resistant Gram-negative pathogens, leads to a sharp increase in mortality globally. However, monotherapies aiming to neutralize LPS often fail to improve the prognosis. Here, an all-in-one drug delivery strategy equipped with bactericidal activity, LPS neutralization, and detoxification is shown to recognize, kill pathogens, and attenuate hyperinflammation by abolishing the activation of LPS-triggered acute inflammatory responses. First, bactericidal colistin results in rapid bacterial killing, and the released LPS is subsequently sequestered. The neutralized LPS is further cleared by acyloxyacyl hydrolase to remove secondary fatty chains and detoxify LPS in situ. Last, such a system shows high efficacy in two mouse infection models challenged with Pseudomonas aeruginosa. This approach integrates direct antibacterial activity with in situ LPS neutralizing and detoxifying properties, shedding light on the development of alternative interventions to treat sepsis-associated infections.

Clinical Outcomes and Predictors of Late Recurrence in Young Patients with Atrial Fibrillation after Catheter Ablation.

Background: Catheter ablation (CA) is an established treatment for atrial fibrillation (AF), but the recurrence of AF is not neglected. Young patients with AF were generally more symptomatic and intolerant to long-term drug treatment. We aim to explore clinical outcomes and predictors of late recurrence (LR) in AF patients younger than 45 years after CA to better manage them. Methods: We retrospectively studied 92 symptomatic AF patients who accepted CA from September 1, 2019, to August 31, 2021. Baseline clinical data (including N-terminal prohormone of brain natriuretic peptide, NT-proBNP), ablation outcomes, and follow-up outcomes were collected. Patients were followed up at 3, 6, 9, and 12 months. Follow-up data were available for 82/92 (89.1%) patients. Results: One-year arrhythmia-free survival was 81.7% (67/82) in our study group. Major complications occurred in 3/82 (3.7%) patients with an acceptable rate. The value of ln(NT-proBNP) (P = 0.025, odds ratio [OR] = 1.977, 95% confidence interval [CI] 1.087-3.596) and a family history of AF (P = 0.041, HR = 9.269, 95% CI 1.097-78.295) could independently predict AF recurrence. The ROC analysis of ln(NT-proBNP) showed that NT-proBNP greater than 200.05 pg/ml (area under the curve: 0.772, 95% CI 0.642-0.902, P = 0.001, sensitivity 0.800, specificity 0.701) was the cut-off point for predicting late recurrence. Conclusions: CA is a safe and effective treatment for AF patients younger than 45 years. Elevated NT-proBNP level and a family history of AF could be used as predictors for late recurrence in young patients. The result of this study may help us take more comprehensive management of those with high-recurrence risks to reduce disease burden and improve quality of life.

Effect of Stereotactic Body Radiation Therapy on Diverse Organ Lesions in Advanced Non-Small Cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors.

OBJECTIVE: The combination of stereotactic body radiation therapy (SBRT) and immune checkpoint inhibitors (ICIs) is actively being explored in advanced non-small-cell lung cancer (NSCLC) patients. However, little is known about the optimal fractionation and radiotherapy target lesions in this scenario. This study investigated the effect of SBRT on diverse organ lesions and radiotherapy dose fractionation regimens on the prognosis of advanced NSCLC patients receiving ICIs. METHODS: The medical records of advanced NSCLC patients consecutively treated with ICIs and SBRT were retrospectively reviewed at our institution from Dec. 2015 to Sep. 2021. Patients were grouped according to radiation sites. Progression-free survival (PFS) and overall survival (OS) were recorded using the Kaplan-Meier method and compared between different treatment groups using the log-rank (Mantel-Cox) test. RESULTS: A total of 124 advanced NSCLC patients receiving ICIs combined with SBRT were identified in this study. Radiation sites included lung lesions (lung group, n=43), bone metastases (bone group, n=24), and brain metastases (brain group, n=57). Compared with the brain group, the mean PFS (mPFS) in the lung group was significantly prolonged by 13.3 months (8.5 months vs. 21.8 months, HR=0.51, 95%CI: 0.28-0.92, P=0.0195), and that in the bone group prolonged by 9.5 months with a 43% reduction in the risk of disease progression (8.5 months vs. 18.0 months, HR=0.57, 95%CI: 0.29-1.13, P=0.1095). The mPFS in the lung group was prolonged by 3.8 months as compared with that in the bone group. The mean OS (mOS) in the lung and bone groups was longer than that of the brain group, and the risk of death decreased by up to 60% in the lung and bone groups as compared with that of the brain group. When SBRT was concurrently given with ICIs, the mPFS in the lung and brain groups were significantly longer than that of the bone group (29.6 months vs. 16.5 months vs. 12.1 months). When SBRT with 8-12 Gy per fraction was combined with ICIs, the mPFS in the lung group was significantly prolonged as compared with that of the bone and brain groups (25.4 months vs. 15.2 months vs. 12.0 months). Among patients receiving SBRT on lung lesions and brain metastases, the mPFS in the concurrent group was longer than that of the SBRT→ICIs group (29.6 months vs. 11.4 months, P=0.0003 and 12.1 months vs. 8.9 months, P=0.2559). Among patients receiving SBRT with <8 Gy and 8-12 Gy per fraction, the mPFS in the concurrent group was also longer than that of the SBRT→ICIs group (20.1 months vs. 5.3 months, P=0.0033 and 24.0 months vs. 13.4 months, P=0.1311). The disease control rates of the lung, bone, and brain groups were 90.7%, 83.3%, and 70.1%, respectively. CONCLUSION: The study demonstrated that the addition of SBRT on lung lesions versus bone and brain metastases to ICIs improved the prognosis in advanced NSCLC patients. This improvement was related to the sequence of radiotherapy combined with ICIs and the radiotherapy fractionation regimens. Dose fractionation regimens of 8-12 Gy per fraction and lung lesions as radiotherapy targets might be the appropriate choice for advanced NSCLC patients receiving ICIs combined with SBRT.

Plant-Derived Xanthones against Clostridial Enteric Infections.

Intestinal bacterial infections are a major threat to human and animal health. In this study, we found plant-derived antibacterial xanthones, particularly α-mangostin (AMG) from the mangosteen peel, exhibiting extraordinary activities against Clostridium perfringens. Structure-activity relationship analysis showed that prenylation modulated the activity of xanthones. The efficacy of AMG (4, 8, 20 mg/kg body weight) was also demonstrated in the broiler chicken necrotic enteritis model infected with Clostridium perfringens. In the models (n = 6 per group), feed supplementation of AMG maintained the homeostasis of the gut microbiome by reducing the colonization of clostridia and promoting the integrity of intestinal barriers via the upregulation of mucin expression. These results suggest that plant-derived xanthones may be a potential alternative to antibiotics for treating clostridial enteric infections in the clinic.

Endocytosis-mediated redistribution of antibiotics targets intracellular bacteria.

The increasing emergence and dissemination of antibiotic resistance pose a severe threat to overwhelming healthcare practices worldwide. The lack of new antibacterial drugs urgently calls for alternative therapeutic strategies to combat multidrug-resistant (MDR) bacterial pathogens, especially those that survive and replicate in host cells, causing relapse and recurrence of infections. Intracellular drug delivery is a direct efficient strategy to combat invasive pathogens by increasing the accumulation of antibiotics. However, the increased accumulation of antibiotics in the infected host cells does not mean high efficacy. The difficulty of treatment lies in the efficient intracellular delivery of antibiotics to the pathogen-containing compartments. Here, we first briefly review the survival mechanisms of intracellular bacteria to facilitate the exploration of potential antibacterial targets for precise delivery. Furthermore, we provide an overview of endocytosis-mediated drug delivery systems, including the biomedical and physicochemical properties modulating the endocytosis and intracellular redistribution of antibiotics. Lastly, we summarize the targets and payloads of recently described intracellular delivery systems and their modes of action against diverse pathogenic bacteria-associated infections. This overview of endocytosis-mediated redistribution of antibiotics sheds light on the development of novel delivery platforms and alternative strategies to combat intracellular bacterial pathogens.

Milk Exosomes Facilitate Oral Delivery of Drugs against Intestinal Bacterial Infections.

Biopharmaceutics Classification System (BCS) class II and IV drugs exhibit low solubility and suffer a limitation in oral administration. Exosomes have attracted intensive attention in the efficient delivery of such compounds. However, low gastrointestinal stability and high production cost of exosomes hinder their development as drug carriers. Here, milk exosomes are functionalized with phosphatidylserine and are capable of improving the solubility of BCS class II and IV drugs, resulting in facilitating the oral delivery of the drugs. A natural flavonoid, α-mangostin, is loaded into exosomes (AExo) to enhance the antibacterial efficiency, demonstrated by clearing 99% of bacteria in macrophages. Furthermore, AExo exhibits high mucus penetrability and shows a significant therapeutic efficacy in two animal infection models. Collectively, this work expands the application of exosomes from bovine milk with simple operation and low cost, shedding light on the potential of milk exosomes in improving the solubility of drugs to enhance the efficacy of oral administration.

Natural Products/Bioactive Compounds as a Source of Anticancer Drugs.

Cancer is one of the major deadly diseases globally. The alarming rise in the mortality rate due to this disease attracks attention towards discovering potent anticancer agents to overcome its mortality rate. The discovery of novel and effective anticancer agents from natural sources has been the main point of interest in pharmaceutical research because of attractive natural therapeutic agents with an immense chemical diversity in species of animals, plants, and microorganisms. More than 60% of contemporary anticancer drugs, in one form or another, have originated from natural sources. Plants and microbial species are chosen based on their composition, ecology, phytochemical, and ethnopharmacological properties. Plants and their derivatives have played a significant role in producing effective anticancer agents. Some plant derivatives include vincristine, vinblastine, irinotecan, topotecan, etoposide, podophyllotoxin, and paclitaxel. Based on their particular activity, a number of other plant-derived bioactive compounds are in the clinical development phase against cancer, such as gimatecan, elomotecan, etc. Additionally, the conjugation of natural compounds with anti-cancerous drugs, or some polymeric carriers particularly targeted to epitopes on the site of interest to tumors, can generate effective targeted treatment therapies. Cognizance from such pharmaceutical research studies would yield alternative drug development strategies through natural sources which could be economical, more reliable, and safe to use.

Equisetin Targets Intracellular Staphylococcus aureus through a Host Acting Strategy.

Mammalian cells act as reservoirs of internalized bacteria to circumvent extracellular antibacterial compounds, resulting in relapse and reinfection diseases. The intracellular persistence of Staphylococcus aureus renders most traditional antibiotics useless, due to their inadequate subcellular accumulation. To replenish our antibiotic arsenal, we found that a marine-derived compound, equisetin, efficiently eliminates intracellular S. aureus by potentiating the host autophagy and inducing mitochondrial-mediated ROS generation to clear the invading S. aureus. The remarkable anti-infection activity of equisetin was validated in a peritonitis-infected mouse model. The marine product equisetin utilizes a unique dual mechanism to modulate the host-pathogen interaction in the clearance of intracellular bacteria. Thus, equisetin is an inspiring host-acting candidate for overcoming intracellular pathogens.

Synergy of outer membrane disruptor SLAP-S25 with hydrophobic antibiotics against Gram-negative pathogens.

OBJECTIVES: An effective strategy for combating MDR Gram-negative pathogens can greatly reduce the cost and shorten the antibiotic development progress. Here, we investigated the synergistic activity of outer membrane disruptor SLAP-S25 in combination with hydrophobic antibiotics (LogP > 2, including novobiocin, erythromycin, clindamycin and rifampicin) against MDR Gram-negative pathogens. METHODS: Five representative Gram-negative bacteria were selected as model strains to analyse the synergistic combination of SLAP-S25 and hydrophobic antibiotics. Carbapenem-resistant hypervirulent Klebsiella pneumoniae CRHvKP4 was used to investigate the synergistic mechanism. The in vivo synergistically therapeutic activity of SLAP-S25 and hydrophobic antibiotics was measured in the mouse peritonitis/sepsis model infected with K. pneumoniae CRHvKP4. RESULTS: SLAP-S25 disrupted the outer membrane by removing LPS from Gram-negative bacteria, facilitating the entry of hydrophobic antibiotics to kill MDR Gram-negative pathogens. Moreover, the combination of SLAP-S25 and rifampicin exhibited promising therapeutic effects in the mouse infection model infected with K. pneumoniae CRHvKP4. CONCLUSIONS: Our findings provide a potential therapeutic strategy to combine SLAP-S25 with hydrophobic antibiotics for combating MDR Gram-negative pathogens.