WO2009081117A1

WO2009081117A1 - Antibacterial combination therapy for the treatment of gram positive bacterial infections

Info

Publication number: WO2009081117A1
Application number: PCT/GB2008/004192
Authority: WO
Inventors: Malcolm Philip Young; Olosola Clement Idowu; Catherine Mary Thomas
Original assignee: E-Therapeutics Plc
Priority date: 2007-12-21
Filing date: 2008-12-19
Publication date: 2009-07-02
Also published as: GB0724996D0

Abstract

There is described a composition comprising a therapeutically active imidazole, or a derivative thereof, and gemfibrozil, or a derivative thereof. There is also described a method of treating a subject suffering from an infection using such a composition.

Description

ANTIBACTERIAL COMBINATION THERAPY FOR THE TREATMENT OF GRAM POSITIVE BACTERIAL INFECTIONS

FmLD OF THE INVENTION The present invention provides a product comprising a synergistic combination of gemfibrozil (5-(2,5-dimethylphenoxy)-2,2-dimethyl-pentanoic acid), or derivative, or structural analog, or metabolite thereof, and a therapeutically active imidazole, as a combined preparation for the treatment of infections caused or contributed to by gram-positive bacteria.

BACKGROUND

Gram-positive bacteria, such as Staphylococci, Streptococci, and Enterococci and Clostridia are extremely important pathogens in both human and veterinary medicine. In the United States, between 1995 and 1998, 60% of hospital bloodstream infections involved gram-positive bacteria. This percentage is continuing to increase. Clostridium difficile is one of the most common causes of hospital-acquired diarrhea. Mortality from C. difficile-associated disease ranges from 6-30% when pseudomembranous colitis (inflammation and bleeding of the colon) is present.

The development of antibiotic resistance amongst gram-positive bacteria complicates treatment and can lead to increased morbidity and mortality.

Antibiotic resistance in bacteria has been selected through the prolific use of these drugs both in human medicine and animal husbandry, indiscriminate prescribing practices, and patient non-compliance with treatment regimes. Therapeutic options for the treatment of such drug-resistant microorganisms, especially gram-positive bacteria, are becoming increasingly limited. The problem of antibiotic resistance is exacerbated by the spread of drug-resistant organisms, and the dissemination of resistance genes between bacteria. The threat to the successful management of bacterial infections posed by the development and spread of antibiotic resistance is one of the most significant problems within healthcare and veterinary medicine.

Staphylococci are major causes of serious healthcare associated infection (HAI). Of particular note are strains of Staphylococcus that have developed or obtained varying levels of resistance to antibiotics such as methicillin (meticillin). These difficult-to- treat organisms are commonly known as methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant Staphylococcus epidermidis (MRSE). Approximately 80% of S. epidermidis isolates from device-associated infections are methicillin resistant (MRSE) as well as being multi-resistant. Resistance to multiple antibiotics and the ability of S. epidermidis to form biofilms on inert surfaces exacerbate the challenges of treating infections caused by these organisms.

In the USA, over 50% of clinical S, aureus isolates are resistant to the β-lactam methicillin (NNIS, 2004). Similarly, reports of methicillin-resistant S. aureus (MRSA) in animals have become more frequent in recent years (O'Mahony et al, 2005); MRSA has been isolated from dogs, cats, cattle, sheep, chickens, rabbits and horses (Devriese and Hommez, 1975, Hartmann et al., 1997, Pak et al, 1999, Tomlin et al, 1999, Lee, 2003, Goni et al, 2004, and Weese 2004). In both human and veterinary medicine, bacterial biofϊlms (structured communities of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface (Costerton et al, 1999)) are a significant problem. In animal husbandry, bacterial biofilms can develop on poultry processing instrumentation (Arnold & Silvers, 2000) and may cause treatment failure of mastitis in cows infected with S. aureus (Melchior et al., 2006). In human healthcare, biofilms of bacteria have been shown to colonise many medical devices, including orthopaedic implants (Bahna et al., 2007). In the UK, 35% of hip prostheses' infection is attributable to S. aureus, resulting in septic loosening, fracture non-union and osteomyelitis (Sanderson, 1991). The association of MRSA with the use of orthopaedic devices is extremely problematic due to the increased spectrum of resistance of this organism, in addition to the protection from the immune system given by the biofϊlm growth phase, often necessitating the removal of a contaminated device, causing further trauma to the patient and increasing medical costs. Colonisation with MRSA is the general precursor to the development of an MRSA infection, so interventions that reduce levels of human colonisation or the colonisation of surfaces such as medical devices will reduce the spread of infections in healthcare facilities.

The acquisition of methicillin resistance among Staphylococcal species not only precludes the use of all currently available β-lactam antibiotics, but also is commonly associated with resistance to multiple drug classes.

Methicillin resistance in Staphylcocci develops by the alteration of the target of the drug, β-lactam antibiotics, such as methicillin, act on sensitive strains by binding to and inhibiting proteins called "Penicillin Binding Proteins". Resistance to methicillin in Staphylococci occurs by the alteration one of these proteins, PBP2', so that β- lactams bind poorly to it. This results in the bacterium becoming resistant to all currently available β-lactam drugs. MRSA and MRSE infections can be treated with glycopeptide drugs, such as vancomycin. The rise in prevalence of MRSA and MRSE, in addition to emerging high levels of resistance to aminoglycosides and ampicillin in Enterococci, have resulted in an increased reliance on vancomycin. This has driven the subsequent emergence of vancomycin resistant pathogens. Of particular note are strains commonly known as vancomycin intermediately sensitive Staphylococcus aureus (VISA) and vancomycin resistant Staphylococcus aureus (VRSA), all of which are multi-drug resistant and difficult to treat. The emergence of VISA and VRSA means that current antibiotics may become ineffective for the treatment of human infections such as endocarditis, bacteraemia and osteomyelitis.

The administration of vancomycin to patients with recurrent MRSA infections causes an increased risk of the emergence of VISA or VRSA strains. The vast majority of

VTSA infections in the USA occur in patients with recurrent MRSA treated with vancomycin (Appelbaum, 2006). Although a dramatic reduction in the use of glycopeptides such as vancomycin would reduce the emergence and spread of VISA and VRSA₅ this is not practical without the use of alternative compounds that do not promote the emergence of multiple resistance.

Similarly, the administration of other broad-spectrum antibiotics, such as ampicillin, amoxicillin and the cephalosporins, plays a key role in the development of

Clostridium difficile-associated diarrhoea (CDAD). Clostridium difficile is extremely hardy; by forming spores, it can survive extremes of temperature, ethanol and antibiotics, and as such is very difficult to treat. The presence of a large number of mobile genetic elements within the genome of C. difficile are thought to be responsible for the multiple-drug resistance observed in this species. The use of these broad-spectrum agents reduces bacterial colonisation in the intestine, permitting the overgrowth of C. difficile. Initially, oral vancomycin was used in the treatment of CDAD₃ but because of the risk of promotion and selection of vancomycin resistant gut flora (such as Enterococci), vancomycin is recommended only for cases that do not respond to the primary treatment (metronidazole). Recently, resistance to vancomycin and metronidazole in C. difficile isolates has been reported, and the use of these agents has been shown to increase the density of vancomycin-resistant Enterococcus (VRE) in the stools of colonised patients.

The development of vancomycin-resistant Enterococci (VRE) in recent years is of major significance. Enterococci once were viewed as harmless inhabitants of the human and animal gut flora, but have now acquired resistance to multiple classes of antibiotic, including the last-resort drug, vancomycin. In the US, the prevalence of Enterococcus faecium exhibiting vancomycin resistance rose from 26.2% in 1995 to around 70% in 2004, making it one of the most feared pathogens in US hospitals.

The acquisition of vancomycin resistance among some strains of Enterococci is associated with resistance to multiple drug classes due to the sequential nature at which these strains have acquired resistance to every new antibiotic challenge. MRSA, MRSE, VISA, VRSA and VRE are genotypically and phenotypically distinct from other, sensitive Staphylococci and Enterococci, tending to form discrete clonal lineages.

The most prevalent clones of MRSA in the UK are EMRSA- 15 and EMRSA- 16; EMRSA- 16 is regarded as endemic in the majority of UK hospitals. These MRSA clones differ from other Staphylococci by the presence of a cassette of several genes (the SCCmec gene cassette), and are commonly resistant to many different classes of antibiotic in addition to metbicillin. This gene cassette contains the genes for methicillin resistance as well as genes important for enabling the cassette to move between strains; it commonly contains many other genes encoding resistance to other antibiotic classes. A genetic comparison between an EMRSA-16 strain and a sensitive Staphylococcal strain revealed that the MRSA strain contained an extra 106 genes, many of which were important for the virulence and drug resistance of the strain.

Similarly, VRE outbreaks are commonly clonal, with the vanA gene cassette (coding for cell-wall precursors that do not bind to vancomycin) being the most prevalent genetic resistance mechanism.

Drug resistance can be specific, i.e. particular to a certain drug or class of drugs, or non-specific in that the resistance applies to a range of drugs, not necessarily related. In the case of VISA, an increase in cell wall thickness is a major contributor to the observed drug resistance. VISA and VRSA may be defined as any staphylococcal strain with a vancomycin MIC of 4-8mg/L (VISA) or greater or equal to 8mg/L (VRSA). These levels of resistance can be due to an increase in cell wall thickness, by the production of cell- wall precursors incapable of binding vancomycin, or via another mechanism. Susceptible gram-positive organisms synthesise cell wall precursors ending in D-ala- D-ala, whereas vancomycin resistant gram-positive organisms, such as VISA, VRSA and VRE synthesise, for example, D-ala-D-lac precursors. The presence of vancomycin resistance in staphylococcal and enterococcal strains may be identified by the measurement of the MIC to vancomycin by broth or agar dilution, or by Etest®, or by the identification of vanA, vanB, vanC, vanD, vanE, vanG genes, or similar, by polymerase chain reaction (PCR). The current invention also encompasses the subclass of VISA strains that are heterogeneous VISA (hVISA); these are vancomycin susceptible methicillin-resistant Staphylococcus aureus by conventional testing but have a sub-population of intermediately resistant cells. hVISA strains are thought to be the precursors of VISA.

The management of human infections caused by MRSA, MRSE, VISA, VRSA and VRE reflect the genotypic and phenotypic differences outlined above, and require greater investment in hospital infrastructure, facilities for patient isolation, and infection control measures than for other strains of Staphylococci and Enterococci. The ease at which Clostridium difficile can spread within the hospital environment, and the ability of the bacterium to form heat-stable antibiotic-resistant spores, means that C. difficile infections also require more extensive infection control measures than those required for most other gram-positive infections; recent cost estimates attributable to CDAD in the UK and USA exceed US$4000 per case. The treatment options for infections contributed to or caused by VISA, VRSA and VRE are now severely limited. Resistance against the two newest antibiotics for VRE (quinupristin-dalfopristin and linezolid) as been described; linezolid has already been associated with treatment failure in VRE infections. There is an urgent need to discover new compounds that inhibit or kill such organisms, and to limit the development and spread of these multiply-resistant pathogens.

Current treatment for Clostridium difficile is not always effective; there are increasing reports of recurring infection and resistance development. CDAD recurs after treatment in up to 50% of patients. Because of the limited therapeutic options for the treatment of CDAD and the high recurrence rate, new therapies are urgently needed.

It has been found that certain imidazoles and or their derivatives are capable of inhibiting the growth of Clostridium difficile (George, 1979), MRSA (Lee & Kim,

1999) and/or VISA, VRSA and VRE (UK patent applications P14994GB and

P148124GB). The antibacterial activity of the imidazoles against multi-resistant

Staphylococci and Enterococci is not predictable from membership of this chemical class; some imidazoles demonstrate antibacterial activity against these difficult to treat organisms, whilst others show none.

Gemfibrozil is known to act synergistically with isoniazid and fluoroquinolones against intracellular bacteria, such as listeria monocytogenes. The reason for this synergy is that gemfibrozil blocks an anionic transporter on the human macrophage cells, thus allowing a higher concentration of fluoroquinolone or isoniazid to accumulate. This property of gemfibrozil has no bearing on bacteria that are not intracellular pathogens, such as Enterococci and Clostridia. In the current invention, the synergistic effect of gemfibrozil with certain imidazoles was demonstrated for bacteria growing without the presence of human cells. Due to the substantial differences between human and bacterial cells, the effect of gemfibrozil on bacterial cells is unpredictable.

Gemfibrozil is known to inhibit the activity of certain membrane transporters by binding to the P-glycoprotein component of the transporter. Bacteria have many different membrane transporters, which differ between species and within a species; proteins coding for over 200 membrane transporters have been identified in one sequenced MRSA strain. The substrates for many of these transporters are unknown.

The ability of the P-glycoprotein inhibitor, gemfibrozil, to act synergistically with certain imidazoles is unique; other P-glycoprotein inhibitors, such as verapamil do not demonstrate this activity.

The present invention discloses the knowledge that the combination of certain imidazoles with gemfibrozil is capable of inhibiting the growth of MRSA, MRSE, VISA, VRSA VRE and Clostridia strains at dramatically lower concentrations than either agent used singly, or their additive effect.

An objective of the present invention is to provide a new and effective treatment for infections contributed to or caused by difficult to treat gram-positive bacteria, such as, MRSA, MRSE, VISA, VRSA VRE and Clostridia. SUMMARY OF THE INVENTION

In a first aspect, the present invention provides a composition comprising a therapeutically active imidazole, and/or a derivative thereof, and gemfibrozil, or derivative, or structural analog, or metabolite thereof.

In particular, the present invention provides a composition as hereinbefore described for treating an infection contributed to or caused by gram-positive bacteria.

The present invention provides a composition as hereinbefore described for treating an infection contributed to or caused by a difficult to treat gram-positive bacterium.

Difficult to treat bacteria include, but shall not be limited to Clostridium difficile and multi-drug resistant organisms.

Such multi-drug resistant bacteria include, but shall not be limited to, MRSA, MRSE, VISA, VRSA, VRE and/or Clostridium.

Furthermore, and in a second aspect, the present invention provides a method of treating a subject suffering from an infection contributed to or caused by multi-drug resistant gram-positive bacteria, said method comprising the step of administering an effective amount of a therapeutically active imidazole, and/or a derivative thereof, with gemfibrozil, or derivative, or structural analog, or metabolite thereof, separately, simultaneously or sequentially. The method of the invention particularly provides a method of treating a subject suffering from an infection contributed to or caused by one or more of MRSA, MRSE, VISA₅ VRSA VRE and/or Clostridium.

In particular, the present invention concerns the use of a compound comprising imidazole and/or derivatives thereof, in combination with gemfibrozil, or derivative, or structural analog, or metabolite thereof, for the preparation of medicaments or for use in methods effective in treating infections contributed to or caused by MRSA, MRSE, VISA₅ VRSA VRE and/or Clostridium.

Exemplary compounds comprising a therapeutically effective imidazole for use in connection with the present invention are provided by the following general formula (Formula I):

Formula I

Wherein:

R₁ and R₂ are independently selected from hydrogen lower alkyl, phenyl or substituted phenyl, wherein said substituted phenyl contains at least one phenyl substituent selected from the group consisting of halo, lower alkyl and lower alkoxy; R is independently selected from hydrogen, lower alkyl, phenyl or substituted phenyl wherein said substituted phenyl contains at least one phenyl substituent selected from the group consisting of halo, lower alkyl and lower alkoxy; Ά_\ is zero or 1;

n₂ is zero or 1; n₃ is zero, 1 or 2 X' is S, Oxy or not present

Ar is independently selected from the group consisting of phenyl, substituted phenyl, thienyl and halothienyl, said substituted phenyl containing at least one phenyl substituent selected from the group consisting of halo, lower alkyl and lower alkoxy;ri₄ is zero or 1

Ar' is a member selected from the group consisting of phenyl, substituted phenyl and α-tetralyl, said substituted phenyl containing at least one phenyl substituent selected from the group consisting of phenyl, thienyl, phenyl thio, halo, lower alkyl, lower alkoxy, cyano, nitro and amino;

R' is a member selected from the group consisting of hydrogen, methyl and ethyl; and R" is a member selected from the group consisting of hydrogen and methyl; provided that: (i) when X is NH, then said R is hydrogen;

(ii) when said Ar' is a substituted phenyl containing at least one phenyl substituent selected from the group consisting of nitro and amino, then said X is oxy and said n₃ is zero; (iii) when said Ar' is α-tetralyl, then said X is NH and said n₃ is zero; and (iv) when X is oxy and said Ar' is a member selected from the group consisting of phenyl and substituted phenyl containing at least one phenyl substituent selected from the group consisting of halo, lower alkyl, lower alkoxy and cyano, then said n₃ is other than zero.

It is to be understood that the terms "lower alkyl" and "lower alkoxy" encompass straight or branch chained hydrocarbons having from about 1 to about 6 carbons, such as, for example, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl and the like alkyls, and, respectively, the corresponding alkoxys such as methoxy, ethoxy, propoxy, isopropoxy, etc.

The preferred lower alkyl and lower alkoxy are methyl and methoxy, respectively. Furthermore, the term "halo" refers to halogens of atomic weight less than 127, i.e., fluoro, iodo, bromo and chloro. Preferred substituted phenyls with respect to the symbol Ar are mono-, di- and trihalo-phenyl, thiol-dihalo-phenyl, lower alkylphenyl and lower alkoxy phenyl; and mono-, di- and tri-halophenyl, di-phenyl, thiol-phenyl, lower alkoxyphenyl, cyanophenyl, mono-, di-nitrophenyl and amino phenyl with regard to the symbol Ar'.

Of particular interest are the therapeutically active imidazoles selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole and derivatives thereof. Especially of interest are the therapeutically active imidazoles selected from the group l-[(2-Chlorophenyl)diρhenylmethyl]-lH-imidazole (C₂₂H₁₇ClN₂), l-[2- [(4-Choloφhenyl)methoxy]-2-(2,4-dichlorophenyl)ethyl]-lH-imidazole (C₁₈H₁₅Cl₃N₂O) and l-[2-(2,4-Dichlorophenyl)-2-[(2,4-dichlorophenyl) methoxy]ethyl]-lH-imidazole (C₁₈H₁₄Cl₄N₂O), otherwise known as clotrimazole, econazole and miconazole, respectively. The formulae for each of these compounds are as follows.

Miconazole

Other compounds of interest may include (±)-l-[4-(4-Chlorophenyl)-2[(2,6- dichlorophenyl)thio]butyl]-lH-imidazole (C₁₉H₁₇Cl₃N₂S: Butoconazole), l-[2-(2,4- Dichlorophenyl)-2-[[4-phenylthio)phenyl]methoxy]ethyl]-lH-imidazole (C₂₄H₂₀Cl₂N₂OS: Fenticonazole), (Z)4-(2,4-DicMorophenyl)-2-(lH-imidazol-l- yl)ethanone O-[2,4-dichlorophenyl)-methyl]oxime mononitrate (CI₈HHCI₄N₄O₄: Oxiconazole Nitrate), l-[2-[(7-chlorobenzothiophen-3-yl)methoxy]-2-(2,4- dichlorophenyl)-ethyl]imidazole (Cs₀H₁₅Cl₃N₂OS: Sertaconazole), l-[2-[[(4- chlorophenyl)methyl]-thio]-2-(2,4-dichlorophenyl)etliyl]-lH-imidazole (C₁₈H₁₅Cl₃N₂S: Sulconazole) and l-[2-[(2-Chloro-3-thienyl)methoxy]-2-(2,4- dichlorophenyl)ethyl]-lH-imidazole (C₁₆H₁₃Cl₃N₂OS: Tioconazole).

In addition, the present invention also encompasses uses of various salts and therapeutically active addition salts of compounds corresponding to formula (I) and derived from the abovementioned compounds comprising imidazole; in particular, for example, miconazole nitrate (C₁₈H₁₄Cl₄N₂O ^• HNO₃), and econazole nitrate (C₁₈H₁₅Cl₃N₂O ^• HNO₃). Derivatives of gemfibrozil as hereinbefore described, shall include, but shall not be limited to, metabolites of gemfibrozil. Thus, compounds comprising gemfibrozil and/or its metabolites or derivatives for use in combination with the above imidazoles in connection with the present invention are provided by the following formula:

Gemfibrozil

It may be convenient or desirable to prepare, purify, and/or handle a corresponding solvate of the compounds described herein, which may be used in any one of the uses/methods described. The term solvate is used herein to refer to a complex of solute, such as a compound or salt of the compound, and a solvent. If the solvent is water, the solvate may be termed a hydrate, for example a mono-hydrate, di-hydrate, tri-hydrate etc, depending on the number of water molecules present per molecule of substrate.

Accordingly, and in one embodiment, the present invention provides a composition comprising one or more of clotrimazole, clotrimazole nitrate, econazole, econazole nitrate, miconazole, miconazole nitrate in combination with gemfibrozil in the manufacture of a medicament for the treatment of an infection contributed to or caused by MRSA, MRSE, VISA, VRSA, VRE and/or Clostridium.

In addition, we provide the use of a therapeutically imidazole in the manufacture of a combination medicament for treating an infection, e.g. an infection contributed to or caused by MRSA thereby reducing the emergence of VISA or VRSA.

We further provide the use of gemfibrozil in the manufacture of a combination medicament with a therapeutically active imidazole for treating an infection e.g. an infection contributed to or caused by MRSA, thereby reducing the emergence of VISA or VRSA.

Advantageously, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof may be administered orally, topically to the site of an infection, transmucosally, transdermally or intravenously. Accordingly, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof may be formulated as polymeric nanoparticles such as alginate or polylactide-co-glycolide nanoparticles, or as sterile pharmaceutical compositions comprising a pharmaceutically acceptable carrier or excipient. Such carriers or excipients are well known to one of skill in the art and may include, for example, water, saline, phosphate buffered saline, dextrose, glycerol, ethanol, ion exchangers, alumina, aluminium stearate, lecithin, serum proteins, such as serum albumin, buffer substances such as phosphates, glycine, sorbic acid, potassium sorbate, partial glyceride mixtures of saturated vegetable fatty acids, lactic acid, water salts or electrolytes, such as protamine sulphate, disodium hydrogen phosphate, potassium hydrogen phosphate, sodium chloride, zinc salts, colloidal silica, magnesium trisilicate, polyvinyl pyrrolidone, cyclodextrins, such as α-cyclodextrin, β-cyclodextrin, sulfobutylether₇- βcyclodextrin and hydroxypropyl-β-cyclodextrin, cellulose-based substances, polyethylene glycol, sodium carboxymethylcellulose, polyacrylates, waxes, polyethylene-polypropylene-block polymers, polyethylene glycol and wool fat and the like, or combinations thereof.

Synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof may be administered in combination with another treatment. For example, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof may be administered in combination with a chemotherapeutic agent, a detergent to facilitate permeation, an immunostimulatory compound or drug, an oligonucleotide, a cytokine, hormone or the like.

It may be possible to administer a synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof, or any combined regime as described above, transdermally via, for example, some form of transdermal delivery device. Such devices are advantageous, particularly for the administration of antibiotic compounds, as they may allow a prolonged period of treatment relative to, for example, an oral or intravenous medicament. Examples of transdermal delivery devices may include, for example, a patch, dressing, bandage or plaster adapted to release a compound or substance through the skin of a patient. A person of skill in the art would be familiar with the materials and techniques which may be used to transdermally deliver a compound or substance and exemplary transdermal delivery devices are provided by GB2185187, US3249109, US3598122, US4144317, US4262003 and US4307717.

By way of example, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof, may be combined with some form of matrix or substrate, such as a non-aqueous polymeric carrier, to render it suitable for use in a transdermal delivery system. This mixture may be further strengthened by the use of a woven or knit, non- woven, relatively open mesh fabric, to produce a patch, bandage, plaster or the like which may be temporarily attached to a particular region of a patient's body. In this way, while in contact with a patient's skin, the transdermal delivery device releases the compound or substance directly to the site of infection or through the skin as required.

The compounds provided herein may also be used as sterilising or cleaning aids for use, for example, on surfaces to reduce and/or eliminate contamination by MRSA, MRSE₅ VISA, VRSA or VRE. By way of example, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof such as, for example miconazole or miconazole nitrate with disulfiram, may be prepared for application to any surface suspected of being contaminated by MRSA, MRSE, VISA, VRSA or VRE. For example, compounds of the present invention may be added to or diluted in an appropriate excipient or solution prior to use as a sterilising or cleaning agent. Exemplary excipients are described above. Such sterilising or cleaning solutions may be used to decontaminate, for example, furniture, floors, equipment including for example specialised hospital equipment and/or surgical equipment.

Advantageously, synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof, may be administered to a medical or veterinary surface to inhibit the growth of MRSA, MRSE, VISA, VRSA VRE and/or Clostridium, and reduce the likelihood of the emergence and spread of vancomycin resistance in that environment. The term "surface" used herein, refers to any surface whether medical or industrial, that provides an interface between a fluid and a solid. The interface between fluid and solid may be intermittent, and may be caused by flowing or stagnant fluid, aerosols, or other means for air-borne fluid exposure. The surface described herein, refers more specifically to a plane whose mechanical structure is compatible with the adherence of bacteria such as S. aureus and Enterococcus species. In the context of the current patent, the terminology "medical or veterinary surface" encompasses the inner and outer aspects of various instruments and devices, both disposable and non-disposable. Examples include the entire spectrum of medical devices

As used herein, the terminology "surfaces found in medical environments" includes the inner and outer aspects of various instruments and devices, whether disposable or intended for repeated uses. Examples include the entire spectrum of articles adapted for medical use, including scalpels, needles, scissors and other devices used in invasive surgical, therapeutic or diagnostic procedures; implantable medical devices, including artificial blood vessels, catheters and other devices for the removal or delivery of fluids to patients, artificial hearts, artificial kidneys, orthopaedic pins, plates and implants; catheters and other tubes (including urological and biliary tubes, endotracheal tubes, peripherally insertable central venous catheters, dialysis catheters, long term tunnelled central venous catheters, peripheral venous catheters, short term central venous catheters, arterial catheters, pulmonary catheters, Swan-Ganz catheters, urinary catheters, peritoneal catheters), urinary devices (including long term urinary devices, tissue bonding urinary devices, artificial urinary sphincters, urinary dilators), shunts (including ventricular or arterio-venous shunts); prostheses (including breast implants, penile prostheses, vascular grafting prostheses, heart valves, artificial joints, artificial larynxes, otological implants), vascular catheter ports, wound drain tubes, hydrocephalus shunts, pacemakers and implantable defibrillators, and the like. Other examples will be readily apparent to practitioners in these arts. Surfaces found in the medical environment also include the inner and outer aspects of pieces of medical equipment, medical gear worn or carried by personnel in the health care setting. Such surfaces can include counter tops and fixtures in areas used for medical procedures or for preparing medical apparatus, tubes and canisters used in respiratory treatments, including the administration of oxygen, of solubilised drugs in nebulisers and of aesthetic agents. Also included are those surfaces intended as biological barriers to infectious organisms in medical settings, such as gloves, aprons and face-shields. Commonly used materials for biological barriers may be latex-based or non-latex based, such as vinyl. Other such surfaces can include handles and cables for medical or dental equipment not intended to be sterile. Additionally, such surfaces can include those non-sterile external surfaces of tubes and other apparatus found in areas where blood or body fluids or other hazardous biomaterials are commonly encountered. In a further embodiment, the compounds described herein may be used to eliminate and/or reduce contamination by MRSA, MRSE, VISA, VRSA VRE and/or Clostridium, on parts of the body, particularly for example, the hands. Synergistic combinations comprising imidazole or derivatives thereof with gemfibrozil and/or derivatives or metabolites thereof, may be diluted as an aqueous or non-aqueous solution (dissolved in aqueous, non aqueous or organic solvent) and which may be applied to a body part, for example the hands. Such a solution may find particular application in, for example hospitals, care homes and or nurseries where the prevalence and transmission rates of MRSA, MRSE, VISA, VRSA VRE and/or Clostridium are often high.

In a further embodiment, the methods and medicaments described herein may be used prophylactically as a means to prevent the development of an infection caused or contributed to by MRSA, MRSE, VISA, VRSA VRE and/or Clostridium, or to reduce the likelihood of the development of VISA or VRSA from an MRSA infection. Medicaments and/or methods for prophylactic use may be administered or applied to any person at risk of developing an infection caused or contributed to by MRSA, MRSE, VISA₅ VRSA VRE and/or Clostridium. For example, people working in care homes, nursing homes, sports centres, community centres, shops, restaurants, cafes, nurseries and/or schools may require prophylactic treatments.

Advantageously, the medicaments and/or methods described herein may have particular application in institutions housing, sheltering, caring or otherwise holding people or patients vulnerable to or "at risk" of developing or contracting MRSA, MRSE, VISA, VRSA VRE and/or Clostridium. The medicaments and methods may be particularly useful in hospitals, nursing homes, nurseries and/or schools. More generally, an elderly, young or immunocompromised person or patient may particularly benefit from the medicaments and methods described herein. Moreover, the methods and medicaments of the present invention may be particularly useful to those undergoing a prolonged stay in hospital, for example in an intensive care facility.

Additionally, or alternatively, the medicaments and methods described herein may be useful in community centres, sports facilities, shops, restaurants, cafes or other places where transmission of bacteria, particularly MRSA, MRSE, VISA, VRSA VRE and/or Clostridium, is likely.

DETAILED DESCRIPTION METHODS:

In example experiments miconazole nitrate, econazole nitrate, and clotrimazole, were dissolved in DMSO. Gemfibrozil was dissolved in ethanol and water. Other solvents that may be used include caster oil, pyridine, and 0.9% saline. For IV administration agents may be solubilised in polyethoxylated caster oil, or cyclodextrins such as sulfobutylether₇-βcyclodextrin or hydroxypropyl-β-cyclodextrin and lactic acid. Minimum inhibitory concentrations (MICs) of a range of clinical and control bacterial organisms were measured according to BSAC (British Society for Antimicrobial Chemotherapy) guidelines (Andrews 2001), for single agents and imidazole with 5l2mg/L gemfibrozil, described briefly as follows. MICs were measured by broth dilution. PREPARATION OF BROTHS.

Stock solutions of each agent were prepared using the formula:

1000 _τ_ _ _w. X Vx C = W

P Where P = μg of active compound per mg (μg/mg) V = volume required (mL) C = final concentration of solution (mg/L) W= weight of agent (mg) to be dissolved in volume V (mL)

Stock solutions were prepared at concentrations of lOOOmg/L and 100mg/L. The appropriate amounts of each stock solution were added to the wells of a 96well microtitre plate to give a range of final concentrations (after the addition of overnight culture of bacteria) from 1 to 32 mg/L. MICs of imidazole were measured with and without the presence of 512mg/L gemfibrozil.

PREPARATION OF INOCULUM

The test organisms were grown overnight in 5mL 1ST broth. Each well of a microtitre plate was inoculated with diluted overnight culture to give a final inoculum of 5 x 10⁵ cfu/mL.

INCUBATION

Microtitre plates were incubated at 37°C in air for 18-20 hours. INTERPRETATION OF RESULTS

The MIC is the minimum amount of an antibiotic at which there is no visible growth of bacteria. Synergy was reported if the inhibitory effect of the drugs in combination were greater than the sum of the inhibitory effects of each drug singly.

RESULTS:

Table one shows that the combination of gemfibrozil (dissolved in ethanol and water) with miconazole gives substantially lower MICs than the comparative MICs for miconazole used singly, against a range of multi-resistant Staphylococcal strains. A growth control demonstrated that the ethanol solute did not affect the measurement of the MICs.

Table 1. MICs by broth dilution demonstrating the effect of gemfibrozil and miconazole used in combination compared to the activity of miconazole used singly.

Table 2. MICs of other imidazoles demonstrating a lack of activity with bifonazole ketoconazole and fluconazole.

Bacteria Strain Bifonazole Ketoconazole Fluconazole

VISA VISA 3900 UK >128 64 >128

VISA USA/VISA 5827 >128 64 >128

Enterocoocus faecium (VRE) NCTC 7171 >128 128 >128

Staphylococcus epidermidis ATCC 1228 >128 64 >128

VISA USA/VISA 5836 >128 64 >128

Enterococcus faecium (VRE) E19 UAA/522 VanB >128 128 >128

Enterococcus faecalis (VRE) E8 VanA >128 >256 >128

Enterococcus faecium (VRE) VaπR B145344C LFE >128 128 >128

Enterococcus faecium (VRE) E15 VanA ATCC 4147 >128 16 >128

Escherichia coli NCTC 10418 >128 >256 >128

Pseudomonas aeruginosa NCTC 10662 >128 >256 >128

Claims

1. A composition comprising a therapeutically active imidazole, or a derivative thereof, and gemfibrozil, or a derivative thereof.

2. A composition according to claim 1 wherein the imidazole, or a derivative thereof, is of the general formula (Formula I):

Formula I

wherein:

R, Ri and R₂, which may be the same or different, are each selected from the group consisting of hydrogen, lower alkyl, phenyl or substituted phenyl, wherein said substituted phenyl contains at least one phenyl substituent selected from the group consisting of halo, lower alkyl and lower alkoxy; R' is a member selected from the group consisting of hydrogen, methyl and ethyl; and

R" is a member selected from the group consisting of hydrogen and methyl;

U₁ is 0 or 1;

X is oxy, S, NH or N =J£> — ; -)- ri2 is 0 or 1; ri3 is 0, 1 or 2; ri4 is 0 or 1; X' is S, Oxy or not present;

Ar is independently selected from the group consisting of phenyl, substituted phenyl, thienyl and halothienyl, said substituted phenyl containing at least one phenyl substituent selected from the group consisting of halo, lower alkyl and lower alkoxy; Ar' is a member selected from the group consisting of phenyl, substituted phenyl and α-tetralyl, said substituted phenyl containing at least one phenyl substituent selected from the group consisting of phenyl, thienyl, phenyl thio, halo, lower alkyl, lower alkoxy, cyano, nitro and amino; provided that: (v) when X is NH, then said R is hydrogen;

(vi) when said Ar' is a substituted phenyl containing at least one phenyl substituent selected from the group consisting of nitro and amino, then said X is oxy and said n₃ is zero; (vii) when said Ar' is α-tetralyl, then said X is NH and said n₃ is zero; and (viii) when X is oxy and said Ar' is a member selected from the group consisting of phenyl and substituted phenyl containing at least one phenyl substituent selected from the group consisting of halo, lower alkyl, lower alkoxy and cyano, then said n₃ is other than zero.

3. A composition according to claim 2 wherein the lower alkyl is a straight or branch chained hydrocarbon having from 1 to about 6 carbons.

4. A composition according to claim 3 wherein the lower alkyl is methyl.

5. A composition according to claim 2 wherein the lower alkoxy is selected from the group consisting of methoxy, ethoxy, propoxy and isopropoxy.

6. A composition according to claim 5 wherein the lower alkoxy is methoxy.

7. A composition according to claim 2 wherein the "halo" group is selected from fluoro, iodo, bromo and chloro.

8. A composition according to claim 2 wherein the substituted phenyl group Ar is selected from mono-, di- and trihalo-phenyl, thiol-dihalo-phenyl, lower alkylphenyl and lower alkoxy phenyl.

9. A composition according to claim 2 wherein the substituted phenyl group Ar' is selected from mono-, di- and tri-halophenyl, di-phenyl, thiol-phenyl, lower alkoxyphenyl, cyanophenyl, mono-, di-nitrophenyl and amino phenyl.

10. A composition according to claim 1 wherein the imidazole is selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole, sertaconazole, sulconazole, tioconazole and derivatives thereof.

11. A composition according to claim 10 wherein the imidazole is selected from the group consisting of clotrimazole, econazole and miconazole, and derivatives thereof.

12. A composition according to claim 11 wherein the imidazole is clotrimazole, or a derivative thereof.

13. A composition according to claim 11 wherein the imidazole is econazole, or a derivative thereof.

14. A composition according to claim 11 wherein the imidazole is miconazole, or a derivative thereof.

15. A composition according to claim 1 wherein the derivative is an imidazole nitrate.

16. A composition according to claim 15 wherein the imidazole nitrate is selected from the group consisting of miconazole nitrate and econazole nitrate.

17. A composition according to claim 1 wherein the gemfibrozil derivative is a metabolite of gemfibrozil.

18. A composition according to claim 17 wherein the metabolite of gemfibrozil is selected from the group consisting of gemfibrozil carboxylic acid-form metabolites, gemfibrozil hydroxylated-form metabolites, and gemfibrozil acyl glucoronides (e.g. 5- (4-hydroxy~2,5- dimethylphenoxy)-2,2-dimethyl-pentanoic acid)).

19. A composition according to claim 1 for prophylactic use.

20. A composition according to claim 1 for treating an infection contributed to or caused by gram-positive bacterium.

21. A composition according to claim 20 wherein the gram-positive bacteria are difficult to treat gram-positive bacterium.

22. A composition according to claim 21 wherein the gram-positive bacteria are selected from the group consisting of Staphylococci, Enter ococci and Clostridia

23. A composition according to claim 22 wherein the difficult to treat gram- positive bacterium are selected from the group consisting of MRSA, MRSE, VISA, VRSA₃ VRE and Clostridia.

24. A composition according to claim 1 wherein the imidazole is selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole and derivatives thereof.

25. A composition according to claim 1 wherein the imidazole is selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole and derivatives thereof.

26. A composition according to claim 1 wherein the imidazole is selected from the group as clotrimazole, econazole and miconazole.

27. A method of treating a subject suffering from an infection contributed to or caused by gram-positive bacteria, said method comprising the step of administering an effective amount of a therapeutically active imidazole, and/or a derivative thereof, with gemfibrozil, or a derivative or a metabolite thereof, separately, simultaneously or sequentially.

28. A method according to claim 27 wherein the gram-positive bacteria are difficult to treat gram-positive bacterium.

29. A method according to claim 28 wherein the gram-positive bacteria are selected from the group consisting of Staphylococci, Enter ococci and Clostridia

30. A method according to claim 29 wherein the gram-positive bacteria are difficult to treat bacteria selected from the group consisting of MRSA, MRSE, VISA,

VRSA, VRE and Clostridia.

31. A method according to claim 30 wherein the imidazole is selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole and derivatives thereof.

32. A method according to claim 31 wherein the imidazole is selected from the group as clotrimazole, econazole and miconazole.

33. The use of a compound comprising imidazole and/or derivatives thereof, in combination with gemfibrozil or a derivative/metabolite thereof, for the manufacture of a medicament for the treatment of infections contributed to or caused by Gram- positive bacteria.

34. The use according to claim 33 wherein the gram-positive bacteria are difficult to treat gram-positive bacterium.

35. The use according to claim 34 wherein the gram-positive bacteria are selected from the group consisting of Staphylococci, Enter ococci and Clostridia

36. The use according to claim 35 wherein the gram-positive bacteria are selected from the group consisting of MRSA, MRSE, VISA₅ VRSA and VRE and Clostridia.

37. The use according to claim 33 wherein the imidazole is selected from the group consisting of clotrimazole, econazole, miconazole, butoconazole, fenticonazole, oxiconazole nitrate, sertaconazole, sulconazole, and tioconazole and derivatives thereof.

38. The use according to claim 37 wherein the imidazole is selected from the group as clotrimazole, econazole and miconazole.

39. The use of a therapeutically effective imidazole in the manufacture of a combination medicament for treating an infection, e.g. an infection contributed to or caused by MRSA thereby reducing the emergence of VISA or VRSA.

40. The use of a therapeutically effective imidazole in the manufacture of a combination medicament for treating an infection contributed to or caused by Clostridia.

41. The use of a gemfibrozil in the manufacture of a combination medicament with a therapeutically active imidazole for treating an infection e.g. an infection contributed to or caused by Gram-positive bacteria, such as, MRSA, thereby reducing the emergence of VISA or VRSA.

42. The use of a gemfibrozil in the manufacture of a combination medicament with a therapeutically active imidazole for treating an infection contributed to or caused by Clostridium.

43. The composition, method or use substantially as hereinbefore described with reference to the accompanying examples.