Salvinorin A protects against methicillin resistant staphylococcus aureus-induced acute lung injury via Nrf2 pathway.

Salvinorin A (SA), a neoclerodane diterpene, is isolated from the dried leaves ofSalvia divinorum. SA has traditionally been used treatments for chronic pain diseases. Recent research has demonstrated that SA possesses the anti-inflammatory property. The present study aim to explore the effects and potentialmechanisms ofSA in protection against Methicillin Resistant Staphylococcus aureus (MRSA)-induced acute lung injury (ALI). Here, we firstly found that verylowdosesof SA (50 µg/kg) could markedly decrease the infiltration of pulmonary neutrophils, mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6) and then attenuated ALI cause by MRSA infection in mice. In vitro findings revealed that SA attenuated lipoteichoicacid-induced apoptosis, inflammation and oxidative stress in RAW264.7 cells. Mechanism research revealed that SA increased both mRNA levels and protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and up-regulated mRNA expression of its downstream genes (HO-1, Gclm, Trx-1, SOD1 and SOD2). Additionally, Nrf2 knockout mice abolished the inhibitory effect of SA on neutrophil accumulation and oxidative stress in MRSA-induced ALI. In conclusion, SA attenuates MRSA-induced ALI via Nrf2 signaling pathways.

Preventing lung pathology and mortality in rabbit Staphylococcus aureus pneumonia models with cytotoxin-neutralizing monoclonal IgGs penetrating the epithelial lining fluid.

Staphylococcus aureus pneumonia is associated with high mortality irrespective of antibiotic susceptibility. Both MRSA and MSSA strains produce powerful cytotoxins: alpha-hemolysin(Hla) and up to five leukocidins - LukSF-PV, HlgAB, HlgCB, LukED and LukGH (LukAB) - to evade host innate defense mechanisms. Neutralizing cytotoxins has been shown to provide survival benefit in rabbit S. aureus pneumonia models. We studied the mechanisms of protection of ASN100, a combination of two human monoclonal antibodies (mAbs), ASN-1 and ASN-2, that together neutralize Hla and the five leukocidins, in rabbit MRSA and MSSA pneumonia models. Upon prophylactic passive immunization, ASN100 displayed dose-dependent increase in survival and was fully protective against all S. aureus strains tested at 5 or 20 mg/kg doses. Macroscopic and microscopic lung pathology, edema rate, and bacterial burden were evaluated 12 hours post infection and reduced by ASN100. Pharmacokinetic analysis of ASN100 in bronchoalveolar-lavage fluid from uninfected animals detected efficient penetration to lung epithelial lining fluid reaching peak levels between 24 and 48 hours post dosing that were comparable to the mAb concentration measured in serum. These data confirm that the ASN100 mAbs neutralize the powerful cytotoxins of S. aureus in the lung and prevent damage to the mucosal barrier and innate immune cells.

Effectual components of Polygonum ciliinerve protects against Staphylococcus aureus infection with immunomodulatory functions in C57BL/6 mice1.

PURPOSE: To investigate the efficacy and mechanisms of root tuber of Polygonum ciliinerve (Nakai) ohwi (rPC) which has been used to treat bacterial infection in traditional Chinese medicine. METHODS: With the mouse model of Staphylococcus aureus (S. aureus) pneumonia, the phenotype of rPC treated mice, including body weight, mortality, lung slices and bacterial burden were evaluated. Furthermore, inflammatory factors in bronchoalveolar lavage (BAL) were determined by ELISA and the distribution of T cells in lung was assessed by immunofluorescence assay. RESULTS: rPC treatment could dose-dependently reduce weight loss and mortality in S. aureus-infected mice. Upon 10 mg/ml rPC treatment, S. aureus-infected mice showed about 8 grams increase in body weight (P<0.001) and 50% enhancement in mortality. The integrity of lung tissue and bacterial burden were also improved by rPC treatment. Moreover, rPC was found to modulate the immune response in infection. CONCLUSION: rPC has therapeutic potential for S. aureus infections and pneumonia with immunomodulatory functions.

Effectual components of Polygonum ciliinerve protects against Staphylococcus aureus infection with immunomodulatory functions in C57BL/6 mice

Abstract Purpose: To investigate the efficacy and mechanisms of root tuber of Polygonum ciliinerve (Nakai) ohwi (rPC) which has been used to treat bacterial infection in traditional Chinese medicine. Methods: With the mouse model of Staphylococcus aureus (S. aureus) pneumonia, the phenotype of rPC treated mice, including body weight, mortality, lung slices and bacterial burden were evaluated. Furthermore, inflammatory factors in bronchoalveolar lavage (BAL) were determined by ELISA and the distribution of T cells in lung was assessed by immunofluorescence assay. Results: rPC treatment could dose-dependently reduce weight loss and mortality in S. aureus-infected mice. Upon 10 mg/ml rPC treatment, S. aureus-infected mice showed about 8 grams increase in body weight (P<0.001) and 50% enhancement in mortality. The integrity of lung tissue and bacterial burden were also improved by rPC treatment. Moreover, rPC was found to modulate the immune response in infection. Conclusion: rPC has therapeutic potential for S. aureus infections and pneumonia with immunomodulatory functions.

Eriodictyol protects against Staphylococcus aureus-induced lung cell injury by inhibiting alpha-hemolysin expression.

Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that causes various diseases in both humans and animals. With the increased prevalence of methicillin-resistant S. aureus, the therapeutic effects of commonly used antibiotics are limited against S. aureus infection. Novel treatment strategies and new antibiotics are needed urgently to address this concern. Many studies have shown that virulence factors secreted from S. aureus play vital roles in their pathogenic processes. Alpha-hemolysin (Hla), an important exotoxin in S. aureus, is one such virulence factor that increases sensitivity of multiple host cells to S. aureus resulting in various diseases. Eriodictyol is a flavonoid compound that exists in many fruits and vegetables. In this study, eriodictyol was demonstrated to inhibit the expression of Hla by hemolysis assays, western blotting, and RT-qPCR at the sub-minimal inhibitory concentration. In live/dead and cytotoxicity assays, the results showed that eriodictyol protected A549 cells against Hla-induced injury in a dose-dependent manner. The minimal inhibitory concentration of eriodictyol against S. aureus was 512 µg/mL. Eriodictyol can downregulate S. aureus Hla at both the expressional and transcriptional levels without affecting S. aureus growth. In addition, cell assays had proved that eriodictyol could protect A549 cells against Hla damage. Eriodictyol could therefore have the potential to treat S. aureus infection targeting Hla.

Intratracheal instillation of neutrophils rescues bacterial overgrowth initiated by trauma damage-associated molecular patterns.

BACKGROUND: Nosocomial pneumonias are common in trauma patients and so interventions to prevent and treat nosocomial pneumonia may improve outcomes. Our prior work strongly suggests that tissue injury predisposes to infections like nosocomial pneumonia because mitochondrial debris originating from injured cells contains damage-associated molecular patterns that can reduce neutrophil (PMN) migration into the airway and diminish PMN function in response to bacterial inoculation of the airway. This suggested that putting exogenous "normal" PMN into the airway might be beneficial. METHODS: Postinjury pneumonia (PNA) commonly arises in two groups, early, community-acquired PNA (CAP) and later hospital-acquired PNA (HAP). Posttraumatic early-onset CAP and late-onset HAP were modeled in CD-1 mice using Staphylococcus aureus or Pseudomonas aeruginosa instilled intratracheal (i.t.) at clinically relevant times with or without extrapulmonary injuries mimicked by an intraperitoneal application of mitochondrial damage-associated molecular patterns. We applied bone marrow-derived PMN (BM-PMN) intratracheally to assess their effect on bacterial clearance in the lung. RESULTS: BM-PMN instillation i.t. had no untoward clinical effects on recipient animals. In both the early/CAP and late/HAP models, clearance of the bacterial inoculum from the lung was suppressed by mitochondrial debris and restored to uninjured levels by i.t. instillation of exogenous BM-PMN. Furthermore, PMN instillation cleared the inoculum of P. aeruginosa that could not be cleared by uninjured mice. Instillation of PMN into the lung, even across strains (CD-1 vs. C57BL/6) had no injurious effect. CONCLUSION: These initial studies suggest PMN instillation (i.t.) is worthy of further study as a potential adjunctive therapy aimed at decreasing the morbidity of lung infections in trauma patients. Moreover, PMN instillation (i.t.) may represent a unique means of preventing or treating pneumonia after serious injury that is completely independent of the need for antibiotic use.

Recombinant lysostaphin protects mice from methicillin-resistant Staphylococcus aureus pneumonia.

The advent of methicillin-resistant Staphylococcus aureus (MRSA) and the frequent and excessive abuse of ventilators have made MRSA pneumonia an inordinate threat to human health. Appropriate antibacterial therapies are crucial, including the use of lysostaphin as an alternative to antibiotics. To explore the potential use of lysostaphin as a therapeutic agent for MRSA pneumonia, mice were intranasally infected with MRSA and then treated with recombinant lysostaphin (rLys; 45 mg/kg in the high-dose group and 1 mg/kg in the low-dose group) (0.33 mg/mL, 15 mg/mL), vancomycin (120 mg/kg) (40 mg/mL), or phosphate-buffered saline (PBS, negative control) 4 h after infection. Therapeutic efficacy was assessed by mouse survival, lung histopathology, bacterial density in the lungs, bodyweight, lung weight, temperature, white blood cells counts, lymphocytes counts, granulocytes counts, and monocytes counts. The mice treated with rLys showed lower mortality, less lung parenchymal damage, and lower bacterial density at metastatic tissue sites than mice treated with PBS or vancomycin. The overall mortality was 100%, 60%, 40%, and 60% for the control, vancomycin, high-dose rLys, and low-dose rLys groups, respectively. These findings indicate that, as a therapeutic agent for MRSA pneumonia, lysostaphin exerts profound protective effects in mice against the morbidity and mortality associated with S. aureus pneumonia.

Chrysin protects mice from Staphylococcus aureus pneumonia.

AIM: To elucidate the effect of chrysin on α-haemolysin production by Staphylococcus aureus and protection against pneumonia in a murine model. METHODS AND RESULTS: Haemolysis, Western blot and real-time RT-PCR assays were performed to evaluate the effect of chrysin on α-haemolysin secretion by Staph. aureus. The efficacy of chrysin against human alveolar epithelial cell injury by α-haemolysin was tested using live/dead staining or by measuring lactate dehydrogenase activity. Furthermore, we determined the protective effect of chrysin against Staph. aureus pneumonia through histopathology experiments in a mouse model. The production of α-haemolysin by Staph. aureus was inhibited when presented with an increasing subinhibitory concentration of chrysin in vitro. Consistent with this result, chrysin prevented α-haemolysin-mediated cell injury and protected mice from Staph. aureus pneumonia. CONCLUSIONS: Chrysin is a potent inhibitor of α-haemolysin expression by Staph. aureus, and it conferred a significant degree of protection against Staph. aureus pneumonia. SIGNIFICANCE AND IMPACT OF STUDY: The chrysin-mediated inhibition of α-haemolysin production and protection against Staph. aureus pneumonia may offer a new strategy in combating pathogen infections.

[MRSA bloodstream infections in hospitals in Frankfurt/Main, Germany, 2010 : Results of the mandatory notification and suggestions for improvement]. / MRSA in Blutkulturen in Frankfurter Krankenhäusern 2010 : Ergebnisse der Meldepflicht nach Infektionsschutzgesetz und Vorschläge zu ihrer Verbesserung.

Since 1 July 2009 in accordance with the statuary order based on the German law for infectious diseases (Infektionsschutzgesetz), MRSA in blood and liquor must be notified to the public health authorities. The aim of extension of the notification to report is to improve the surveillance of nosocomial infections and the prevention of nosocomial MRSA infections. In addition to MRSA detection, data on symptoms and risk factors, e.g., medical devices, must also be reported. In this report, data of bloodstream MRSA infections in hospitals in Frankfurt/Main, Germany, for the first complete year (2010)were evaluated. In 2010, 58 MRSA-positive bloodstream infections were reported by the 17 hospitals in Frankfurt to the health protection authorities, i.e., 0.0360 MRSA/1,000 patient-days (range: 0- 0.109/1,000 patient-days). However, 10 of these infections initially had not been reported to the public health department in charge for the hospitals, but to the health departments according to the patient's addresses. Although most of the infections were reported from large hospitals (>100,000 patient-days/year), the highest incidences (0.0416/1,000 patient-days) were reported from small hospitals (<50,000 patient-days/year). Of the blood specimen, 13 (22.4%) were drawn on the first day of hospital stay, thus, indicating an imported infection. While 90% of the patients with MRSA in the bloodstream suffered from fever, 80% had sepsis and 34.5% suffered from pneumonia. Medical devices, such as central venous catheters and PEG, were reported from 60% of the patients. In the MRE network Rhine-Main region, the public health authorities asked for some more detailed information, such as risk factors for MRSA colonization (history for MRSA, recent hospital stay or antibiotic therapy, skin disorders, dialysis, residence in a retirements home), and for screening results as well as for the MRSA management, i.e., isolation of the patient and, if necessary, the contact patient. In 55% of the cases, the patients were identified by the clinics themselves as being patients with MRSA risk factors, mainly because of a history of MRSA (29%), recent hospital stay (71%), and antibiotic therapy during the last 6 months (52%). Screening was performed in 31 (53%) of the patients, most of them (71%) with positive MRSA nose swab. If the patients were screened, significantly fewer contact patients had to be screened and isolated later. Thus, to improve surveillance data on MRSA bloodstream infections, the notification route to the public health authorities responsible for the clinic hosting the patient must be strictly obeyed in order to avoid underreporting und underassessment of nosocomial infection. Although asking for clinical symptoms may be useful to validate the result in some cases, focus should be placed on risk factors and risk management, including screening and isolation. Only then can the aim of improving surveillance and reduction of nosocomial MRSA infection be achieved.

An evaluation of the emerging vaccines and immunotherapy against staphylococcal pneumonia in children.

BACKGROUND: Staphylococcus aureus is a commensal of human skin and nares. It is also one of the leading nosocomial pathogens in both developed and developing countries and is responsible for a wide range of life threatening infections, especially in patients who are immunocompromised, post-surgery, undergoing haemodialysis and those who are treated with catheters and ventilators. Over the past two decades, the incidence of nosocomial staphylococcal infections has increased dramatically. Currently there are at least seven vaccine and immunotherapy candidates against S. aureus in the developmental phase targeting both active and passive immunization. METHODS: We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging vaccines against Staphylococcus aureus relevant to several criteria of interest: answerability; cost of development, production and implementation; efficacy and effectiveness; deliverability, affordability and sustainability; maximum potential impact on disease burden reduction; acceptability to the end users and health workers; and effect on equity. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies) to participate. The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to sensitive nature of their involvement in such exercises. They answered questions from CHNRI framework and their "collective optimism" towards each criterion was documented on a scale from 0 to 100%. RESULTS: The panel of experts expressed low levels of optimism (score around or below 50%) on the criteria of answerability, efficacy, maximum disease burden reduction potential, low cost of production, low cost of implementation and affordability; moderate levels of optimism (scores around 60 to 80%) that these vaccines could be developed at a low cost, and thus on the deliverability, sustainability and impact on equity; and high levels of optimism (scores above 80%) regarding acceptable of such a product to both the end-users and health workers. While assessing the candidates for passive immunization against S.aureus, the experts were poorly optimistic regarding low production cost, low implementation cost, efficacy, deliverability, sustainability, affordability and equity; moderately optimistic regarding answerability and acceptability to health workers and end-users. They were of the opinion that these interventions would have only a modest impact (3 to 5%) on the burden of childhood pneumonia. . CONCLUSION: In order to provide an effective vaccine against S. aureus, a number of unresolved issues in vaccine development relating to optimal antigenic target identification, criteria for acceptable efficacy, identification of target population, commercial development limitations, optimal timing of immunization strategy, storage, cold chain requirements and cost need to be addressed properly. There is still a great deal unknown about the complex interaction between S. aureus and the human host. However, given the nature of S. aureus and the lessons learned from the recent failure of two emerging vaccines, it is clear that a multi-component vaccine is essential. Combating only one virulence factor is not sufficient in the human host but finding the right combination of factors will be very challenging.

Methicillin-resistant staphylococcus aureus screening and eradication in the surgical intensive care unit: Is it worth it?

BACKGROUND: The problem of intensive care unit methicillin-resistant Staphylococcus aureus (MRSA) infections has led to routine surveillance and eradication strategies. METHODS: Our surgical intensive care unit (SICU) admissions receive MRSA nares cultures and if positive are isolated followed by eradication treatment. This strategy was retrospectively reviewed. RESULTS: Our nares-positive culture rate was 21% (30/145), and the sputum positive (sputum+) rate was 18% (26/145). Positive nares culture (Nares+) was eradicated in 63%. The rate of sputum+ in Nares+ patients was 36% (9/25). The rate of sputum+ in Nares- was 10% (12/115; P = .003). The sputum+ SICU length of stay (LOS) (18 ± 12 days in 23 S+ patients) is longer than in sputum- (10 ± 9 days in 69 S-patients, P = .0002). CONCLUSIONS: This SICU has high rates of both nares and sputum MRSA cultures. Our data suggest eradicating nares colonization may prevent pneumonia and might decrease SICU LOS.

Protection with antibody to tumor necrosis factor differs with similarly lethal Escherichia coli versus Staphylococcus aureus pneumonia in rats.

BACKGROUND: Differing factors may alter the effects of antibody to tumor necrosis factor (TNF) in infection and sepsis. The authors tested whether bacteria type or treatment route alters antibody to TNF in a rat model of bacterial pneumonia. METHODS: Rats (n = 231) received similarly lethal doses of either intratracheal Escherichia coli or Staphylococcus aureus followed by treatment with either intratracheal or intraperitoneal antibody to TNF or control serum. Animals received antibiotics (cefotiam daily dose, 100 mg/kg) starting 4 h after inoculation and were studied for up to 96 h. RESULTS: Compared with S. aureus, E. coli increased serum TNF and interleukin-6 concentrations, lung lavage TNF concentrations, neutrophil counts, and alveolar-to-arterial oxygen gradients and decreased circulating neutrophils and lymphocytes (P > or = 0.05 for all). Compared with controls, with both bacteria, except for lung lavage TNF concentrations (which decreased with intratracheal but not with intraperitoneal antibody to TNF), treatment route did not alter the effects of antibody to TNF on any parameter (P = not significant for all). Antibody to TNF reduced mortality rates (relative risk of death +/- SEM) with both E. coli (-1.6 +/- 0.6; P = 0.006) and S. aureus (-0.5 +/- 0.04; P = 0.185), but these reductions were greater with E. coli than with S. aureus in a trend approaching statistical significance (P = 0.09). Compared with controls, similarly (P = not significant) with both bacteria, antibody to TNF decreased lung lavage and tissue bacteria concentrations (both P < 0.05) and serum TNF concentration (P < 0.09) and increased circulating neutrophils and lymphocytes (both P < or = 0.01). Compared with S. aureus, with E. coli antibody to TNF decreased alveolar-to-arterial oxygen gradients (P = 0.04) and increased serum interleukin-6 concentrations (P = 0.003). CONCLUSION: Antibody to TNF improved host defense and survival rates with both lethal E. coli and S. aureus pneumonia, but protection was greater with E. coli, where TNF concentrations were higher than with S. aureus. The efficacy of antiinflammatory agents in sepsis may be altered by bacteria type.

Antibiotic prophylaxis in infants and young children with cystic fibrosis: a randomized controlled trial.

OBJECTIVES: To evaluate whether antistaphylococcal prophylaxis in infants and young children with cystic fibrosis (CF) would suppress the acquisition of Staphylococcus aureus and delay the onset of the manifestations of bronchopulmonary disease. STUDY DESIGN: A 7-year, multicenter, double-blind, placebo-controlled study of continuous antistaphylococcal therapy. Otherwise healthy children <2 years of age with CF were randomly assigned to be treated with daily cephalexin (80-100 mg/kg/day) or placebo. Clinical, microbiologic, laboratory, radiographic, and anthropometric outcomes were evaluated. RESULTS: Of 209 children enrolled, 119 completed a 5- to 7-year course of therapy. Mean age at enrollment was 15.6 and 14.1 months in the cephalexin and placebo groups, respectively. Respiratory cultures from children treated with cephalexin were significantly less likely to be positive for S aureus (6.0% vs 30.4%; P <.001). They were, however, much more likely to be positive for Pseudomonas aeruginosa (25.6% vs 13.5%; P <.009). These differences became apparent in the first year after enrollment and persisted over the duration of the study. In contrast to these microbiologic differences, there were no differences in clinical outcome measures, including radiographic (Brasfield score, 23.4 vs 23.2) or anthropometric scores or pulmonary function. CONCLUSIONS: Although long-term prophylaxis with cephalexin successfully delayed the acquisition of S aureus, it enhanced colonization with P aeruginosa and did not lead to clinically significant improvement in major health outcomes. These data do not support routine antistaphylococcal prophylaxisin otherwise healthy infants and young children with CF.

MRSA in cystic fibrosis. London, 16 June 1997.

This is a report of a consensus meeting held in London on 16 June 1997, where microbiologists and clinicians reviewed the implications of colonization/infection of patients with cystic fibrosis by methicillin-resistant Staphylococcus aureus (MRSA).

Factors associated with influenza and pneumococcal vaccination behavior among high-risk adults.

OBJECTIVE: This cross-sectional survey assessed factors associated with influenza and pneumococcal vaccination behaviors among high-risk patients exposed to highly organized vaccination programs. INTERVENTIONS: Self-administered questionnaires were mailed to 700 patients randomly selected from the outpatient roster of the medical center. Questions were asked about patient demographic and health characteristics in addition to their knowledge and attitudes regarding influenza and pneumococcal diseases and vaccines. MAIN RESULTS: After three mailings, the response rate was 68%, and 80% of these respondents were in a high-risk ++group. Influenza and pneumococcal vaccination rates for high-risk respondents were 74.4% and 62.5%, respectively. Factors independently associated with both influenza and pneumococcal vaccination behaviors included health care providers' recommendations and having positive attitudes toward immunization. In addition, for influenza vaccination, willingness to comply with the provider's recommendation was also associated with receipt of the vaccine while cigarette smoking was associated with failure to receive the vaccine. CONCLUSIONS: Emphasis on provider recommendations and the knowledge and attitudes of patients may enhance influenza and pneumococcal vaccination rates, even in the context of organized vaccination programs.