Publications by authors named "Mark I Richards"

Melioidosis is a disease that is difficult to treat due to the causative organism, being inherently antibiotic resistant and it having the ability to invade, survive, and replicate in an intracellular environment. Combination therapy approaches are routinely being evaluated in animal models with the aim of improving the level of protection and clearance of colonizing bacteria detected. In this study, a subunit vaccine layered with the antibiotic finafloxacin was evaluated against an inhalational infection with in Balb/c mice.

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Antimicrobial resistance is a global issue, and the investigation of alternative therapies that are not traditional antibiotics are warranted. Novel bacterial type II topoisomerase inhibitors (NBTIs) have recently emerged as a novel class of antibiotics with reduced potential for cross-resistance to fluoroquinolones due to their novel mechanism of action. This study investigated the activity of a series of cyclohexyl-oxazolidinone bacterial topoisomerase inhibitors against type strains of and .

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, the causative agent of glanders, is principally a disease of equines, although it can also infect humans and is categorized by the U.S. Centers for Disease Control and Prevention as a category B biological agent.

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is the causative agent of melioidosis, a multifaceted disease. A proportion of the mortality and morbidity reported as a result of infection with this organism may be due to the premature cessation of antibiotic therapy typically lasting for several months. The progression of re-emergent disease was characterised in Balb/c mice following cessation of a 14 day treatment course of co-trimoxazole or finafloxacin, delivered at a human equivalent dose.

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The efficacy of finafloxacin as a component of a layered defense treatment regimen was determined and against an infection with . Doxycycline was down-selected from a panel of antibiotics evaluated and used in combination with finafloxacin in a Balb/c mouse model of inhalational melioidosis. When treatment was initiated at 24 h post-infection with , there were no differences in the level of protection offered by finafloxacin or doxycycline (as monotherapies) when compared to the combination therapy.

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Finafloxacin is a novel fluoroquinolone with optimal antibacterial activity in low pH environments, therefore offering a therapeutic advantage over some traditional antibiotics, in treating bacterial infections associated with acidic foci. , the causative agent of Q fever, is a bacterium which resides and replicates in acidic intracellular parasitic vacuoles. The efficacy of finafloxacin was evaluated using the A/J mouse model of inhalational Q fever and was compared to doxycycline, the standard treatment for this infection and ciprofloxacin, a comparator fluoroquinolone.

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Burkholderia pseudomallei is a soil-dwelling organism present throughout the tropics. It is the causative agent of melioidosis, a disease that is believed to kill 89,000 people per year. It is naturally resistant to many antibiotics, requiring at least two weeks of intravenous treatment with ceftazidime, imipenem or meropenem followed by 6 months of orally delivered co-trimoxazole.

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Infection with aerosolized or can lead to lethal disease in humans if treatment is not initiated promptly. Finafloxacin is a novel fluoroquinolone which has demonstrated broad-spectrum activity against a range of bacterial species , and in humans, activity which is superior in acidic, infection-relevant conditions. Human-equivalent doses of finafloxacin or ciprofloxacin were delivered at 24 h (representing prophylaxis) or at 72 or 38 h (representing treatment) postchallenge with or , respectively, in BALB/c mouse models.

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This study investigated the activity of finafloxacin against panels of the biodefence pathogens. Broth microdilution assays were performed at neutral and acidic pH, to determine the effectiveness of the antibiotics in conditions typical of an intracellular environment. In all instances, finafloxacin demonstrated superior activity at low pH.

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Burkholderia pseudomallei is the causative agent of the tropical disease melioidosis. Its genome encodes an arsenal of virulence factors that allow it, when required, to switch from a soil dwelling bacterium to a deadly intracellular pathogen. With a high intrinsic resistance to antibiotics and the ability to overcome challenges from the host immune system, there is an increasing requirement for new antibiotics and a greater understanding into the molecular mechanisms of B.

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The efficacy of the novel fluoroquinolone finafloxacin was evaluated as a potential therapeutic and , following an intranasal infection of strain SchuS4 in BALB/c mice. We demonstrated that short treatment courses of finafloxacin provide high levels of protection, with a single dose resulting in a significant increase in time to death when compared to ciprofloxacin. In addition, following investigation into the window of opportunity for treatment, we have shown that finafloxacin can provided protection when administered up to 96 h post-challenge.

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is the causative agent of melioidosis, a serious disease endemic in Southeast Asia and Northern Australia. Antibiotic treatment is lengthy and relapse often occurs. Finafloxacin is a novel fluoroquinolone with increased antibacterial activity in acidic conditions in contrast to other fluoroquinolones which demonstrate reduced activity at a lower pH.

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Article Synopsis
  • The innate immune response is crucial for protecting mice from Francisella tularensis live vaccine strain (LVS) infections, particularly when triggered early.
  • The human cathelicidin LL-37, known for its immunomodulatory properties, shows promise as a post-exposure therapy against LVS, enhancing immune responses and increasing survival time in mice.
  • While LL-37 administration improves immune activity and delays death after LVS exposure, its protective effects are temporary, suggesting that a longer treatment duration may be more effective for combating the infection.
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Francisella tularensis is an intracellular pathogen capable of multiplying to high levels in macrophages. By protein analysis, only a few proteins have been shown previously to be expressed at high levels in macrophages relative to bacteria grown in culture media. To identify additional genes that show increased expression during intracellular growth, we developed a plasmid for use in Francisella based on the induction of expression of green fluorescent protein.

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