26 results on '"Robins‐Browne, Roy"'
Search Results
2. Chips with everything: DNA microarrays in infectious diseases
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Bryant, Penelope A., Venter, Deon, Robins-Browne, Roy, and Curtis, Nigel
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Microbiology -- Analysis ,Evolution -- Analysis ,Human genetics -- Analysis ,DNA microarrays -- Analysis ,Gene expression -- Analysis ,DNA -- Analysis ,Genomes -- Analysis ,Children -- Diseases ,Children -- Analysis - Published
- 2004
3. Cytokine biomarkers for the diagnosis of tuberculosis infection and disease in adults in a low prevalence setting.
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Clifford, Vanessa, Tebruegge, Marc, Zufferey, Christel, Germano, Susie, Forbes, Ben, Cosentino, Lucy, Matchett, Elizabeth, McBryde, Emma, Eisen, Damon, Robins-Browne, Roy, Street, Alan, Denholm, Justin, and Curtis, Nigel
- Abstract
Abstract Objective Accurate and timely diagnosis of tuberculosis (TB) is essential to control the global pandemic. Currently available immunodiagnostic tests cannot discriminate between latent tuberculosis infection (LTBI) and active tuberculosis. This study aimed to determine whether candidate mycobacterial antigen-stimulated cytokine biomarkers can discriminate between TB-uninfected and TB-infected adults, and additionally between LTBI and active TB disease. Methods 193 adults were recruited, and categorised into four unambiguous diagnostic groups: microbiologically-proven active TB, LTBI, sick controls (non-TB lower respiratory tract infections) and healthy controls. Whole blood assays were used to determine mycobacterial antigen (CFP-10, ESAT-6, PPD)-stimulated cytokine (IL-1ra, IL-2, IL-10, IL-13, TNF-α, IFN-γ, IP-10 and MIP-1β) responses, measured by Luminex multiplex immunoassay. Results The background-corrected mycobacterial antigen-stimulated cytokine responses of all eight cytokines were significantly higher in TB-infected participants compared with TB-uninfected individuals, with IL-2 showing the best performance characteristics. In addition, mycobacterial antigen-stimulated responses with IL-1ra, IL-10 and TNF-α were higher in participants with active TB compared those with LTBI, reaching statistical significance with PPD stimulation, although there was a degree of overlap between the two groups. Conclusion Mycobacterial antigen-stimulated cytokine responses may prove useful in future immunodiagnostic tests to discriminate between tuberculosis-infected and tuberculosis-uninfected individual, and potentially between LTBI and active tuberculosis. [ABSTRACT FROM AUTHOR]
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- 2019
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4. Mycobacteria-specific cytokine responses as correlates of treatment response in active and latent tuberculosis.
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Clifford, Vanessa, Tebruegge, Marc, Zufferey, Christel, Germano, Susie, Forbes, Ben, Cosentino, Lucy, McBryde, Emma, Eisen, Damon, Robins-Browne, Roy, Street, Alan, Denholm, Justin, and Curtis, Nigel
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DRUG therapy for tuberculosis ,TUBERCULOSIS diagnosis ,ANTITUBERCULAR agents ,BACTERIAL antigens ,CYTOKINES ,DRUG monitoring ,LONGITUDINAL method ,MYCOBACTERIUM tuberculosis ,TUBERCULOSIS - Abstract
Objectives: A biomarker indicating successful tuberculosis (TB) therapy would assist in determining appropriate length of treatment. This study aimed to determine changes in mycobacteria-specific antigen-induced cytokine biomarkers in patients receiving therapy for latent or active TB, to identify biomarkers potentially correlating with treatment success.Methods: A total of 33 adults with active TB and 36 with latent TB were followed longitudinally over therapy. Whole blood stimulation assays using mycobacteria-specific antigens (CFP-10, ESAT-6, PPD) were done on samples obtained at 0, 1, 3, 6 and 9 months. Cytokine responses (IFN-γ, IL-1ra, IL-2, IL-10, IL-13, IP-10, MIP-1β, and TNF-α) in supernatants were measured by Luminex xMAP immunoassay.Results: In active TB cases, median IL-1ra (with CFP-10 and with PPD stimulation), IP-10 (CFP-10, ESAT-6), MIP-1β (ESAT-6, PPD), and TNF-α (ESAT-6) responses declined significantly over the course of therapy. In latent TB cases, median IL-1ra (CFP-10, ESAT-6, PPD), IL-2 (CFP-10, ESAT-6), and IP-10 (CFP-10, ESAT-6) responses declined significantly.Conclusions: Mycobacteria-specific cytokine responses change significantly over the course of therapy, and their kinetics in active TB differ from those observed in latent TB. In particular, mycobacteria-specific IL-1ra responses are potential correlates of successful therapy in both active and latent TB. [ABSTRACT FROM AUTHOR]- Published
- 2017
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5. Risk factors for intussusception in infants in Vietnam and Australia: Adenovirus implicated, but not rotavirus.
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Bines, Julie E., Liem, Nguyen Thanh, Justice, Frances A., Son, Tran Ngoc, Kirkwood, Carl D., de Campo, Margaret, Barnett, Peter, Bishop, Ruth F., Robins-Browne, Roy, and Carlin, John B.
- Abstract
Objective: This study aimed to investigate risk factors for the development of intussusception in infants in a developing country with a suspected high incidence and in a developed country with a low incidence. Study design: A prospective case-control study of infants <2 years of age with idiopathic intussusception confirmed by air enema or surgery was conducted at the National Hospital of Paediatrics (NHP), Vietnam (n = 533) and the Royal Children’s Hospital (RCH), Australia (n = 51). Diagnosis was validated in a subset (84% NHP; 67% RCH) by an independent blinded radiologist. Risk factor assessment was performed using a standardized questionnaire. Stool specimens were assayed for bacterial, viral, and parasitic agents. Results: The incidence of intussusception in Vietnam was 302/100,000 in infants <1 year of age (95% CI: 258-352), substantially higher than in Australia (71/100,000). A strong association with adenovirus infection was observed at both sites (cases positive at NHP: 34%, OR 8.2; cases positive at RCH: 40%, OR 44). No association was identified between intussusception and rotavirus, other enteric pathogens, oral polio vaccine, feeding practices, or living conditions. Conclusions: The incidence of intussusception in infants was markedly higher in Vietnam than in Australia. A strong association between adenovirus infection and intussusception was identified at both sites suggesting that adenovirus may play a role in the etiology of intussusception. [Copyright &y& Elsevier]
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- 2006
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6. Probiotic use in clinical practice: what are the risks?
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Boyle, Robert J., Robins-Browne, Roy M., and Tang, Mimi L. K.
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Probiotics have been advocated for the prevention and treatment of a wide range of diseases, and there is strong evidence for their efficacy in some clinical scenarios. Probiotics are now widely used in many countries by consumers and in clinical practice. Given the increasingly widespread use of probiotics, a thorough understanding of their risks and benefits is imperative. In this article we review the safety of probiotics and discuss areas of uncertainty regarding their use. Although probiotics have an excellent overall safety record, they should be used with caution in certain patient groups--particularly neonates born prematurely or with immune deficiency. Because of the paucity of information regarding the mechanisms through which probiotics act, appropriate administrative regimens, and probiotic interactions, further investigation is needed in these areas. Finally, note that the properties of different probiotic species vary and can be strain-specific. Therefore, the effects of one probiotic strain should not be generalized to others without confirmation in separate studies. Careful consideration should be given to these issues before patients are advised to use probiotic supplements in clinical practice. [ABSTRACT FROM AUTHOR]
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- 2006
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7. Hemolytic Uremic Syndrome.
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Elliott, Elizabeth Jane and Robins-Browne, Roy Michael
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- 2005
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8. Prenatal probiotic administration can influence Bifidobacterium microbiota development in infants at high risk of allergy.
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Lahtinen, Sampo J., Boyle, Robert J., Kivivuori, Satu, Oppedisano, Frances, Smith, Katherine R., Robins-Browne, Roy, Salminen, Seppo J., and Tang, Mimi L.K.
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- 2009
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9. Immunization with a whole cell vaccine reduces pneumococcal nasopharyngeal density and shedding, and middle ear infection in mice.
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Manning, Jayne, Manna, Sam, Dunne, Eileen M., Bongcaron, Viktoria, Pell, Casey L., Patterson, Natalie L., Kuil, Sacha D., Dhar, Poshmaal, Goldblatt, David, Kim Mulholland, E., Licciardi, Paul V., Robins-Browne, Roy M., Malley, Richard, Wijburg, Odilia, and Satzke, Catherine
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MIDDLE ear , *PNEUMOCOCCAL vaccines , *EAR infections , *STREPTOCOCCUS pneumoniae , *IMMUNOGLOBULINS , *IMMUNIZATION , *NASOPHARYNX - Abstract
• Therapeutic administration of a pneumococcal whole cell vaccine was evaluated. • Whole cell vaccine reduces pneumococcal nasopharyngeal density. • The reduction in density requires antibodies. • Whole cell vaccine also reduced pneumococcal shedding and middle ear infection. Pneumococcal Conjugate Vaccines (PCVs) have substantially reduced the burden of disease caused by Streptococcus pneumoniae (the pneumococcus). However, protection is limited to vaccine serotypes, and when administered to children who are colonized with pneumococci at the time of vaccination, immune responses to the vaccine are blunted. Here, we investigate the potential of a killed whole cell pneumococcal vaccine (WCV) to reduce existing pneumococcal carriage and mucosal disease when given therapeutically to infant mice colonized with pneumococci. We show that a single dose of WCV reduced pneumococcal carriage density in an antibody-dependent manner. Therapeutic vaccination induced robust immune responses to pneumococcal surface antigens CbpA, PspA (family 1) and PiaA. In a co-infection model of otitis media, a single dose of WCV reduced pneumococcal middle ear infection. Lastly, in a two-dose model, therapeutic administration of WCV reduced nasal shedding of pneumococci. Taken together, our data demonstrate that WCV administered in colonized mice reduced pneumococcal density in the nasopharynx and the middle ear, and decreased shedding. WCVs would be beneficial in low and middle-income settings where pneumococcal carriage in children is high. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Hepatitis B vaccine co-administration influences the heterologous effects of neonatal BCG vaccination in a sex-differential manner.
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Pittet, Laure F., Cox, Lianne, Freyne, Bridget, Germano, Susie, Bonnici, Rhian, Gardiner, Kaya, Donath, Susan, Collins, Clare L., Casalaz, Dan, Robins-Browne, Roy, Flanagan, Katie L., Messina, Nicole L., and Curtis, Nigel
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BCG vaccines , *HEPATITIS B vaccines , *MONOCYTES , *HEPATITIS B , *RANDOMIZED controlled trials - Abstract
• BCG vaccination reduced IFN-γ and MCP-1 responses to heterologous stimulants. • HBV vaccination alone did not alter heterologous cytokine responses. • Males overall produced more IFN-γ and TNF-α compared with females. • HBV co-administration influenced the heterologous effects of neonatal BCG vaccination in a sex-differential manner. Bacille Calmette-Guérin (BCG) and hepatitis B (HBV) vaccines are frequently given concomitantly at birth. Neonatal BCG vaccination induces off-target immunological effects. Whether HBV vaccine has immunomodulatory effects is unknown. As off-target effects might vary when vaccines are given simultaneously, this randomised controlled trial aimed to evaluate the influence of neonatal vaccination with BCG and/or HBV on heterologous immune responses. A total of 185 neonates in Australia were randomised to receive either neonatal BCG-Denmark vaccine, HBV vaccine, both (BCG + HBV group), or none (No vaccine group). In-vitro responses to heterologous stimulants were assessed 7 days after vaccination. The influence of (i) randomisation group and (ii) sex on interferon-gamma (IFN-γ), monocyte chemoattractant protein-1 (MCP-1), and tumour necrosis factor-alpha (TNF-α) responses was analysed using linear regression. Overall, BCG vaccination alone or with HBV co-administration reduced IFN-γ and MCP-1 responses to heterologous stimulants. HBV vaccination alone did not alter heterologous cytokine responses. In general, males produced more IFN-γ and TNF-α than females. We observed a sex-differential effect in relation to the influence of HBV co-administration on the effect of BCG on heterologous responses. Compared with males in the No vaccine group, males in the BCG + HBV group had lower IFN-γ and MCP-1 responses. In contrast, compared with females in the No vaccine group, females in the BCG group had higher IFN-γ response and lower MCP-1 responses. Neonatal BCG vaccination resulted in lower cytokine responses to unrelated pathogens. HBV co-administration did not have a significant impact on responses overall but influenced the heterologous effects of neonatal BCG vaccination in a sex-differential manner. [ABSTRACT FROM AUTHOR]
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- 2022
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11. Nasopharyngeal microbial interactions in the era of pneumococcal conjugate vaccination.
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Dunne, Eileen M., Smith-Vaughan, Heidi C., Robins-Browne, Roy M., Mulholland, E. Kim, and Satzke, Catherine
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NASOPHARYNX diseases , *PNEUMOCOCCAL vaccines , *PATHOGENIC microorganisms , *COLONIZATION , *ETIOLOGY of diseases , *VACCINATION of children - Abstract
Highlights: [•] Clinically important pathogens often colonise the nasopharynx of children. [•] Vaccination may alter colonisation dynamics and impact disease aetiology. [•] We review co-colonisation of pathogens and the impact of pneumococcal vaccination. [ABSTRACT FROM AUTHOR]
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- 2013
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12. Control of bacterial virulence by AraC-like regulators that respond to chemical signals
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Yang, Ji, Tauschek, Marija, and Robins-Browne, Roy M.
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MICROBIAL virulence , *PATHOGENIC bacteria , *CELLULAR signal transduction , *GENE expression , *PREVENTIVE medicine , *GENE targeting , *METABOLISM , *BENZOATES - Abstract
This review highlights the exciting new finding that small molecule inducers have been found for some members of the AraC family of transcriptional regulators (AFTRs) that control the expression of virulence genes of pathogenic bacteria. Although effector-mediated activation of AFTRs involved in the regulation of sugar and alkylbenzoate catabolism (e.g. AraC and XylS) is well understood, until recently little was known about effector-mediated regulation of virulence gene expression. This led to the belief that regulation of virulence by AFTRs does not involve the direct recognition of chemical environmental signals. More recently, however, a growing number of virulence-associated AFTRs have been found to directly sense environmental chemicals. Most interestingly, these environmental chemicals are abundant at the sites where the bacterial pathogen colonizes and damages its host. In this article we review recent developments in the field of environmental regulation mediated by virulence-associated AFTRs, with a focus on the sensing of environmental signals, the mechanism of gene target activation, and the effector-mediated modulation of regulator activities. [ABSTRACT FROM AUTHOR]
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- 2011
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13. Mycobacterium ulcerans-specific immune response after immunisation with bacillus Calmette-Guérin (BCG) vaccine.
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Pittet, Laure F., Tebruegge, Marc, Dutta, Binita, Donath, Susan, Messina, Nicole, Casalaz, Dan, Hanekom, Willem A., Britton, Warwick J., Robins-Browne, Roy, Curtis, Nigel, and Ritz, Nicole
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IMMUNE response , *IMMUNIZATION , *MYCOBACTERIUM , *BURULI ulcer , *BCG vaccines , *MATERNALLY acquired immunity - Abstract
• Infant BCG immunisation induces M. ulcerans -specific immune responses. • M. ulcerans - and M. tuberculosis -specific immune responses are qualitatively similar. • Magnitude of M. ulcerans -specific immune responses was not influenced by BCG strain. • These in-vitro findings support the protective effect observed epidemiologically. Bacillus Calmette–Guérin (BCG) vaccine provides partial protection against Buruli ulcer caused by Mycobacterium ulcerans in epidemiological studies. This study aimed to quantify M. ulcerans -specific immune responses induced by BCG immunisation. Intracellular cytokine analysis of in-vitro experiments done 10 weeks after BCG immunisation in 130 Australian infants randomised to one of three BCG vaccine strains given either at birth (BCG-Denmark, BCG-Japan, or BCG-Russia) or at two months of age (BCG-Denmark). Proportions of polyfunctional CD4+ T-cells were higher in M. ulcerans -stimulated compared to unstimulated control samples. These proportions were not influenced by the vaccine strain or timing of the immunisation. The M. ulcerans -specific immune responses showed similar patterns to those observed in M. tuberculosis -stimulated samples, although they were of lower magnitude. Our data show that BCG immunisation induces M. ulcerans -specific immune responses in infants, likely explaining the cross-protective effect observed in epidemiological studies. (ACTRN12608000227392) [ABSTRACT FROM AUTHOR]
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- 2021
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14. Effect of a pneumococcal whole cell vaccine on influenza A-induced pneumococcal otitis media in infant mice.
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Manning, Jayne, Dunne, Eileen M., Wang, Nancy, Pedersen, John S., Ogier, Jacqueline M., Burt, Rachel A., Mulholland, E. Kim, Robins-Browne, Roy M., Malley, Richard, Wijburg, Odilia L., and Satzke, Catherine
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OTITIS media , *INFLUENZA vaccines , *VIRUS inactivation , *MIDDLE ear , *MICE , *PNEUMOCOCCAL vaccines - Abstract
• Investigation of pneumococcal WCV on influenza-induced pneumococcal otitis media. • WCV did not prevent OM but reduced pneumococcal loads in ears for 1 of 2 strains. • Reduction in pneumococcal density was antibody and CD4+ T cell dependent. The pneumococcus remains a common cause of otitis media (OM) despite the widespread introduction of pneumococcal conjugate vaccines. In mice, a pneumococcal whole cell vaccine (WCV) induces serotype-independent protection against pneumococcal colonisation and invasive disease via T H 17- and antibody-mediated immunity, respectively. We investigated the effect of WCV on influenza A-induced pneumococcal OM in an infant mouse model. C57BL/6 mice were immunised subcutaneously with a single dose of WCV or adjuvant at 6 days of age, infected with pneumococci (EF3030 [serotype 19F] or PMP1106 [16F]) at 12 days of age, and given influenza A virus (A/Udorn/72/307 [H3N2], IAV) at 18 days of age to induce pneumococcal OM. Pneumococcal density in middle ear and nasopharyngeal tissues was determined 6 and 12 days post-virus. Experiments were repeated in antibody (B6.μMT−/−)- and CD4+ T-cell-deficient mice to investigate the immune responses involved. A single dose of WCV did not prevent the development of pneumococcal OM, nor accelerate pneumococcal clearance compared with mice receiving adjuvant alone. However, WCV reduced the density of EF3030 in the middle ear at 6 days post-viral infection (p = 0.022), and the density of both isolates in the nasopharynx at 12 days post-viral infection (EF3030, p = 0.035; PMP1106, p = 0.011), compared with adjuvant alone. The reduction in density in the middle ear required antibodies and CD4+ T cells: WCV did not reduce EF3030 middle ear density in B6.μMT−/− mice (p = 0.35) nor in wild-type mice given anti-CD4 monoclonal antibody before and after IAV inoculation (p = 0.91); and WCV-immunised CD4+ T cell-deficient GK1.5 mice had higher levels of EF3030 in the middle ear than their adjuvant-immunised counterparts (p = 0.044). A single subcutaneous dose of WCV reduced pneumococcal density in the middle ears of co-infected mice in one of two strains tested, but did not prevent OM from occurring in this animal model. [ABSTRACT FROM AUTHOR]
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- 2019
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15. Antibacterial activity of rhodomyrtone on Clostridium difficile vegetative cells and spores in vitro.
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Srisuwan, Sutthirat, Mackin, Kate E., Hocking, Dianna, Lyras, Dena, Bennett-Wood, Vicki, Voravuthikunchai, Supayang P., and Robins-Browne, Roy M.
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ANTIBACTERIAL agents , *CLOSTRIDIOIDES difficile , *PLANT spores , *VANCOMYCIN , *BIOACTIVE compounds , *GRAM-positive bacteria - Abstract
Highlights • Rhodomyrtone is a natural compound derived from leaves of the rose myrtle. • MIC of rhodomyrtone for Clostridium difficile was similar to that of vancomycin. • Bactericidal activity of rhodomyrtone was greater than that of vancomycin. • Rhodomyrtone prevented C. difficile spore outgrowth more effectively than vancomycin. • Rhodomyrtone lysed C. difficile cells and interfered with cell division and spore formation. ABSTRACT The increasing incidence and severity of diarrhoea and colitis caused by Clostridium difficile , together with a high rate of relapse following treatment with currently recommended antimicrobials, calls for novel interventions for C. difficile infection (CDI). Rhodomyrtone, a bioactive compound derived from the leaves of the rose myrtle (Rhodomyrtus tomentosa) has demonstrated antibacterial activity against several Gram-positive bacteria. This study compared the in vitro antimicrobial activity of rhodomyrtone on C. difficile with that of vancomycin, a recommended agent for the treatment of CDI. Determination of the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of rhodomyrtone and vancomycin for ten C. difficile isolates showed that the MICs of rhodomyrtone for C. difficile vegetative cells (0.625–2.5 mg/L) were comparable with that of vancomycin (1.25 mg/L), but the MBCs of rhodomyrtone (1.25–5 mg/L) were significantly lower than those for vancomycin (5 mg/L to ˃40 mg/L; P < 0.001). Time–kill assays showed rapid bactericidal activity for rhodomyrtone, with ≥99% killing within 4 h. Rhodomyrtone was also four-fold more potent than vancomycin in inhibiting C. difficile spore outgrowth. Transmission electron microscopy of rhodomyrtone-treated C. difficile revealed cell lysis and evidence of defective cell division and spore formation. These studies indicate that rhodomyrtone should be further investigated as a potential treatment for CDI. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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16. Structural Determinants Defining the Allosteric Inhibition of an Essential Antibiotic Target.
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Soares da Costa, Tatiana P., Desbois, Sebastien, Dogovski, Con, Gorman, Michael A., Ketaren, Natalia E., Paxman, Jason J., Siddiqui, Tanzeela, Zammit, Leanne M., Abbott, Belinda M., Robins-Browne, Roy M., Parker, Michael W., Jameson, Geoffrey B., Hall, Nathan E., Panjikar, Santosh, and Perugini, Matthew A.
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ALLOSTERIC regulation , *ANTIBIOTICS , *GRAM-negative bacteria , *STREPTOCOCCUS pneumoniae , *GRAM-positive bacteria , *CRYSTALLOGRAPHY , *THERMOPHORESIS ,LYSINE synthesis - Abstract
Summary Dihydrodipicolinate synthase (DHDPS) catalyzes the first committed step in the lysine biosynthesis pathway of bacteria. The pathway can be regulated by feedback inhibition of DHDPS through the allosteric binding of the end product, lysine. The current dogma states that DHDPS from Gram-negative bacteria are inhibited by lysine but orthologs from Gram-positive species are not. The 1.65-Å resolution structure of the Gram-negative Legionella pneumophila DHDPS and the 1.88-Å resolution structure of the Gram-positive Streptococcus pneumoniae DHDPS bound to lysine, together with comprehensive functional analyses, show that this dogma is incorrect. We subsequently employed our crystallographic data with bioinformatics, mutagenesis, enzyme kinetics, and microscale thermophoresis to reveal that lysine-mediated inhibition is not defined by Gram staining, but by the presence of a His or Glu at position 56 ( Escherichia coli numbering). This study has unveiled the molecular determinants defining lysine-mediated allosteric inhibition of bacterial DHDPS. [ABSTRACT FROM AUTHOR]
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- 2016
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17. Comparable CD4 and CD8 T cell responses and cytokine release after at-birth and delayed BCG immunisation in infants born in Australia.
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Ritz, Nicole, Casalaz, Dan, Donath, Susan, Tebruegge, Marc, Dutta, Binita, Connell, Tom G., Robins-Browne, Roy, Britton, Warwick J., Hanekom, Willem A., and Curtis, Nigel
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BCG vaccines , *CD antigens , *T cells , *CYTOKINES , *IMMUNE response , *FETAL immunology - Abstract
Background More than 120 million doses of BCG vaccine are administered worldwide each year. Most infants are given BCG at birth in accordance with WHO recommendations. However, the effect of the maturing neonatal immune system on the immune response and protection conferred by BCG remains uncertain. Previous studies investigating the influence of age at immunisation on the immune response induced by BCG have reported conflicting results. This study compared BCG given at birth and at two months of age in infants in Australia. Methods Infants born in Melbourne were randomly allocated to immunisation with BCG-Denmark at birth or two months of age. Ten weeks after immunisation, anti-mycobacterial immune responses were measured in a whole blood assay using intracellular cytokine assays and xMAP multiplex cytokine analysis. Results Result from 98 BCG-immunised infants were included in the final analysis. BCG immunisation at birth ( n = 54) and at 2 months of age ( n = 44) induced comparable proportions of mycobacteria-specific cytokine-producing CD4 and CD8 T cells, as well as comparable proportions of polyfunctional (TNF + IL-2 + IFN-γ + ) CD4 T cells. Concentrations of cytokines in supernatants were also similar in both groups. Conclusions Cellular immunity measured 10 weeks after BCG immunisation was similar in infants given BCG at birth and in those given BCG at 2 months of age. Although definitive correlates of protection against TB remain uncertain, these results suggest that delaying BCG immunisation does not confer any immunological advantage in cellular immunity. [ABSTRACT FROM AUTHOR]
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- 2016
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18. Site of fluorescent label modifies interaction of melittin with live cells and model membranes.
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Jamasbi, Elaheh, Ciccotosto, Giuseppe D., Tailhades, Julien, Robins-Browne, Roy M., Ugalde, Cathryn L., Sharples, Robyn A., Patil, Nitin, Wade, John D., Hossain, Mohammed Akhter, and Separovic, Frances
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MELITTIN , *CELL membranes , *FLUORESCENCE microscopy , *N-terminal residues , *LECITHIN , *CELL-mediated cytotoxicity - Abstract
The mechanism of membrane disruption by melittin (MLT) of giant unilamellar vesicles (GUVs) and live cells was studied using fluorescence microscopy and two fluorescent synthetic analogues of MLT. The N-terminus of one of these was acylated with thiopropionic acid to enable labeling with maleimido-AlexaFluor 430 to study the interaction of MLT with live cells. It was compared with a second analogue labeled at P14C. The results indicated that the fluorescent peptides adhered to the membrane bilayer of phosphatidylcholine GUVs and inserted into the plasma membrane of HeLa cells. Fluorescence and light microscopy revealed changes in cell morphology after exposure to MLT peptides and showed bleb formation in the plasma membrane of HeLa cells. However, the membrane disruptive effect was dependent upon the location of the fluorescent label on the peptide and was greater when MLT was labeled at the N-terminus. Proline at position 14 appeared to be important for antimicrobial activity, hemolysis and cytotoxicity, but not essential for cell membrane disruption. [ABSTRACT FROM AUTHOR]
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- 2015
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19. Streptococcal superantigens: categorization and clinical associations.
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Commons, Robert J., Smeesters, Pierre R., Proft, Thomas, Fraser, John D., Robins-Browne, Roy, and Curtis, Nigel
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STREPTOCOCCAL diseases , *SUPERANTIGENS , *BACTERIAL antigens , *GENETICS of bacterial diseases , *BIOLOGICAL nomenclature - Abstract
Highlights: [•] The currently confused nomenclature of streptococcal superantigens is clarified. [•] Guidelines for future superantigen classification are proposed. [•] Evidence for superantigen involvement in clinical disease is summarized. [ABSTRACT FROM AUTHOR]
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- 2014
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20. Disarming Bacterial Virulence through Chemical Inhibition of the DNA Binding Domain of an AraC-like Transcriptional Activator Protein.
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Ji Yang, Hocking, Dianna M., Cheng, Catherine, Dogovski, Con, Perugini, Matthew A., Holien, Jessica K., Parker, Michael W., Hartland, Elizabeth L., Tauschek, Marija, and Robins-Browne, Roy M.
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ANTIBIOTICS , *DRUG resistance in bacteria , *DRUG resistance in microorganisms , *MICROBIAL virulence , *GRAM-negative bacterial diseases , *BACTERIAL disease treatment - Abstract
The misuse of antibiotics during past decades has led to pervasive antibiotic resistance in bacteria. Hence, there is an urgent need for the development of new and alternative approaches to combat bacterial infections. In most bacterial pathogens the expression of virulence is tightly regulated at the transcriptional level. Therefore, targeting pathogens with drugs that interfere with virulence gene expression offers an effective alternative to conventional antimicrobial chemotherapy. Many Gram-negative intestinal pathogens produce AraC-like proteins that control the expression of genes required for infection. In this study we investigated the prototypical AraC-like virulence regulator, RegA, from the mouse attaching and effacing pathogen, Citro-bacter rodentium, as a potential drug target. By screening a small molecule chemical library and chemical optimization, we identified two compounds that specifically inhibited the ability of RegA to activate its target promoters and thus reduced expression of a number of proteins required for virulence. Bio-physical, biochemical, genetic, and computational analyses indicated that the more potent of these two compounds, which we named regacin, disrupts the DNA binding capacity of RegA by interacting with amino acid residues within a conserved region of the DNA binding domain. Oral administration of regacin tomice, commencing 15min before or 12 h after oral inoculation with C. rodentium, caused highly significant attenuation of intestinal colonization by themouse pathogen comparable to that of an isogenic regA-deletion mutant. These findings demonstrate that chemical inhibition of the DNA binding domains of transcriptional regulators is a viable strategy for the development of antimicrobial agents that target bacterial pathogens. [ABSTRACT FROM AUTHOR]
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- 2013
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21. A totally synthetic lipopeptide-based self-adjuvanting vaccine induces neutralizing antibodies against heat-stable enterotoxin from enterotoxigenic Escherichia coli
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Zeng, Weiguang, Azzopardi, Kristy, Hocking, Dianna, Wong, Chinn Yi, Robevska, Gorjana, Tauschek, Marija, Robins-Browne, Roy M., and Jackson, David C.
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ENTEROTOXINS , *ESCHERICHIA coli , *TOLL-like receptors , *CYSTEINE , *INTRANASAL medication , *LABORATORY mice - Abstract
Abstract: ST-based lipopeptide vaccine candidates were constructed in which ST was chemically synthesized and folded into the correct conformation prior to ligation to a module containing a T-helper cell epitope (TH) and the Toll-like receptor 2 (TLR2) agonist, S-[2,3-bis(palmitoyloxy)propyl]cysteine (P2C). Two different chemistries, thioether-based and oxime-based, were then used to ligate ST to the lipidated TH epitope. The enterotoxic activity of synthetic ST and the ST-based lipopeptide vaccines was determined in mice followed by an evaluation of immunological efficacy. The importance of the fine detail in chemical composition used in vaccine design was demonstrated by the findings that (i) the oxime-based vaccine exhibited little or no toxicity but the thioether-based vaccine, exhibited residual toxicity in suckling mice, (ii) although each of the synthetic vaccines generated specific anti-ST antibodies, it was the low titer antibodies induced by the oxime-based vaccine that demonstrated better neutralizing activity suggesting that the chemical linkage also affects the specificity of antibodies, (iii) the geometric arrangement of ST within a vaccine can profoundly affect the specificity and biological function of the antibodies that are elicited, and (iv) the lipopeptide-based ST vaccine candidate assembled using oxime chemistry induced a better neutralizing antibody response to ST when administered by the mucosal (intranasal) route. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
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22. A Modular Approach to Assembly of Totally Synthetic Self-adjuvanting Lipopeptide-based Vaccines Allows Conformational Epitope Building.
- Author
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Weiguang Zeng, Horrocks, Kylie J., Robevska, Gorjana, Chinn Yi Wong, Azzopardi, Kristy, Tauschek, Marija, Robins-Browne, Roy M., and Jackson, David C.
- Subjects
- *
SYNTHETIC vaccines , *EPITOPES , *AMINO acid sequence , *CELLULAR immunity , *ESCHERICHIA coli , *INFLUENZA vaccines , *ENTEROTOXINS , *T cells - Abstract
The technology described here allows the chemical synthesis of vaccines requiring correctly folded epitopes and that contain difficult or long peptide sequences. The final self-adjuvanting product promotes strong humoral and/or cell-mediated immunity. A module containing common components of the vaccine (T helper cell epitope and the adjuvanting lipid moiety S-[2,3-bis(palmitoyloxy)propyl]cysteine) was assembled to enable a plug and play approach to vaccine assembly. The inclusion within the module of a chemical group with chemical properties complementary and orthogonal to a chemical group present in the target epitope allowed chemoselective ligation of the two vaccine components. The heat-stable enterotoxin of enterotoxigenic Escherichia coil that requires strict conformational integrity for biological activity and the reproductive hormone luteinizing hormone-releasing hormone were used as the target epitopes for the antibody vaccines. An epitope from the acid polymerase of influenza virus was used to assemble a CD8+ T cell vaccine. Evaluation of each vaccine candidate in animals demonstrated the feasibility of the approach and that the type of immune response required, viz, antibody or cytotoxic T lymphocyte, dictates the nature of the chemical linkage between the module and target epitope. The use of a thioether bond between the module and target epitope had little or no adverse effect on antibody responses, whereas the use of a disulfide bond between the module and target epitope almost completely abrogated the antibody response. In contrast, better cytotoxic T lymphocyte responses were obtained when a disulfide bond was used. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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- View/download PDF
23. Rabbit-specific fimbriae, Ral, alter the patterns of in vitro adherence and intestinal colonisation of rabbits by human-specific enteropathogenic E. coli
- Author
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Hart, Emily, Tauschek, Marija, Bennett-Wood, Vicki, Hartland, Elizabeth L., and Robins-Browne, Roy M.
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PILI (Microbiology) , *LABORATORY rabbits , *PATHOGENIC microorganisms , *ESCHERICHIA coli , *DIARRHEA in children , *INFANT mortality , *CELL membranes ,DEVELOPING countries - Abstract
Abstract: Enteropathogenic Escherichia coli (EPEC) poses a significant threat to human health, causing diarrhoea in children worldwide, and is a leading cause of infant mortality in developing countries. The pathogenic effects of EPEC and other attaching-effacing (A/E) bacteria result from adhesion to the intestinal mucosa by a variety of mechanisms, including fimbrial adhesins, which are believed to contribute to the host and tissue specificity of EPEC by their interaction with specific receptors on cell surfaces. In this study we investigated the contribution of a fimbrial adhesin, Ral, of rabbit-specific EPEC (REPEC) to host specificity by introducing Ral into derivatives of human-specific EPEC (hEPEC) strain, E2348/69, in which expression of the fimbrial adhesin, Bfp, had been interrupted. Although unable to cause diarrhoeal disease in rabbits, Ral-bearing hEPEC strains colonised rabbit intestine more efficiently and showed altered intestinal localisation when compared to an isogenic Ral-negative strain. These findings suggest that Ral enhances the initial interaction between a ΔbfpA mutant of hEPEC and rabbit intestine and may influence tissue specificity, but is not sufficient on its own to transform hEPEC into a rabbit pathogen. This study affords new insights into the complex mechanisms which determine the host range of bacterial pathogens. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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24. Liposomal phospholipid preparations of chloramphenicol for ophthalmic applications.
- Author
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Mahmoud, Sherif S., Gehman, John D., Azzopardi, Kristy, Robins-Browne, Roy M., and Separovic, Frances
- Subjects
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LIPOSOMES , *PHOSPHOLIPIDS , *BILAYER lipid membranes , *CHLORAMPHENICOL , *STAPHYLOCOCCUS , *BACTERIAL diseases , *STAPHYLOCOCCUS aureus infections - Abstract
Since their discovery by Bangham and coworkers almost four decades ago, liposomes have become models for biomembranes and vehicles for pharmaceutical, diagnostic, and cosmetic agents. One of the advantages of using liposomes as a drug vehicle is their ability for slow release, thus reducing dosage, localizing a drug, and minimizing its side-effects. Antibiotic resistance is a growing global problem, including for ocular bacterial infection by Staphylococcus aureus, where time is an important parameter that determines the severity of infection. This situation has prompted the pursuit of ways to prepare drug-encapsulating liposomes that enable bulk release of the drug chloramphenicol (CAP) once the liposomal structure is perturbed. Our approach is a two-step process: first, to characterize the interaction of CAP with model biomembranes of dimyristoylphosphatidylcholine (DMPC) used to prepare CAP-liposomes by different formulations; second, to test the efficiency of these formulation against S. aureus. Solid-state NMR, differential scanning calorimetry, and infrared spectroscopy were used to study the interaction of CAP with DMPC bilayers. The minimum inhibitory concentrations and time-kill curves for S. aureus using different liposomal preparations were compared. Evidence of conformational changes in the DMPC molecules and the effectiveness of the CAP encapsulated in liposomes are reported. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2691–2701, 2008 [ABSTRACT FROM AUTHOR]
- Published
- 2008
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25. Mechanisms, organisms and markers of infection in pregnancy
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Garland, Suzanne M., Nı Chuileannáin, Fiona, Satzke, Catherine, and Robins-Browne, Roy
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PREGNANCY complications , *PREMATURE infants , *CYTOKINES - Abstract
Premature delivery is still a significant problem in Obstetrics. It has multiple causes, with around 50% thought due to infection. Of note infection as a pathogenesis is more likely in those pre-term births occurring <30 weeks gestation and is largely sub-clinical. Potential pathogens largely arise from the ascending route and from the endogenous vaginal flora, causing chorioamnionitis. Resultant morbidity from the release of endo+/exotoxins from such pathogens, the stimulation and production of inflammatory cytokine pathways, prostaglandins, metalloproteinases includes maternal sepsis (chorioamnionitis, septicaemia, post-partum endometritis), pre-term delivery (infant pre-maturity and its consequences, increased susceptibility to cerebral palsy and neonatal sepsis). As well, infection increases mortality due to fetal loss (extreme pre-maturity) as well as severe neonatal sepsis. [Copyright &y& Elsevier]
- Published
- 2002
- Full Text
- View/download PDF
26. Meningitis in children in Fiji: etiology, epidemiology, and neurological sequelae
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Biaukula, Viema Lewagalu, Tikoduadua, Lisi, Azzopardi, Kristy, Seduadua, Anna, Temple, Beth, Richmond, Peter, Robins-Browne, Roy, Mulholland, Edward Kim, and Russell, Fiona Mary
- Subjects
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MENINGITIS in children , *ETIOLOGY of diseases , *EPIDEMIOLOGY , *QUALITY of life , *STREPTOCOCCUS , *BLOOD testing , *CEREBROSPINAL fluid - Abstract
Summary: Objectives: To describe the etiology, epidemiology, neurological sequelae, and quality of life of children aged 1 month to less than 5 years admitted with meningitis to the Colonial War Memorial Hospital (CWMH), Suva, Fiji. Methods: Over a 3-year period, all eligible children with suspected meningitis admitted to CWMH had blood drawn for culture. Of these children, those for whom is was possible were tested for a four-fold rise in antibody titers to Haemophilus influenzae type b (Hib) and pneumococcal surface adhesin A (PsaA). Cerebrospinal fluid (CSF) was taken for bacteriological culture and antigen testing. CSF was also tested by PCR for Streptococcus species, Neisseria meningitidis, Hib, Mycobacterium tuberculosis, and enterovirus. Pneumococcal isolates were serotyped using multiplex-PCR reverse-line blot hybridization. Following discharge, cases underwent a neurological assessment, audiometry, and quality of life assessment (Pediatric Quality of Life Inventory (PedsQL) tool). Results: There were 70 meningitis cases. Meningitis was more common in indigenous Fijian than Indo-Fijian children. Enterovirus was the most common etiological agent and appeared to be outbreak-associated. Streptococcus pneumoniae was the most common bacterial cause of meningitis with an annual incidence of 9.9 per 100 000 under 5 years old (95% confidence interval 4.9–17.7) and a case fatality rate of 36%. With the exception of deafness, neurological sequelae were more frequent in cases of bacterial meningitis than in viral meningitis (18.5% vs. 0%, p =0.04). Quality of life at follow-up was significantly lower in patients with bacterial meningitis than in those with viral meningitis (p =0.003) or meningitis of unknown etiology (p =0.004). Conclusions: During the study period an outbreak of enterovirus occurred making it the most common etiological agent identified. However in the absence of this outbreak, S. pneumoniae was the most common cause of childhood meningitis in Fiji. Bacterial meningitis is associated with serious sequelae and a reduced quality of life. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
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