FIELD OF INVENTION

The invention relates to the halogenated salicylanilides closantel, rafoxanide, oxyclozanide or niclosamide and derivatives thereof including salts, hydrates, esters for use in the topical treatment or prevention of conditions caused by Gram positive bacteria such asStaphylococcus,in particularStaphylococcus aureus,andStreptococcus,in particularStreptococcus pyogenes.The halogenated salicylanilides have a surprisingly low frequency of appearance of resistant mutants in said strains compared to commonly used topical antibiotics. Also provided are topical formulations comprising a halogenated salicylanilide.

BACKGROUND OF THE INVENTION

Today, there are many different classes of antibiotics available to medical practitioners. However, many of the bacteria that these antibiotics are designed to treat are quickly developing resistance to drugs in all classes. Unfortunately the large pharmaceutical companies have limited there research in finding new antibiotics. Several bacteria have become particularly prominent in recent years and have garnered substantial media attention, especially methicillin-resistantStaphylococcus aureus(“MRSA”) andStreptococcus pyogenes.MRSA infections on the skin and in the airways are common in hospital settings and the broad spectrum resistance of the bacteria to almost all classes of antibiotics (e.g. methicillin, fusidic acid and mupirocin) make it particularly difficult to combat. MRSA infections in patients who have not recently been in hospital (so called community acquired MRSA infections) are becoming increasingly frequent.

The problem of antibiotic resistance is an increasing problem, but a truly comprehensive solution to the problem has yet to emerge. A major problem in the battle against antibiotic resistance is the lack of novel antibiotics to replace those that no longer effectively treat organisms due to resistance development. New treatments are urgently needed to address this issue of drug resistance.

Fusidic acid is an antibiotic derived fromFusidium coccineumthat has been used for over 35 years to treat infections withStaphylococcus aureus.In particular, fusidic acid is prescribed for skin infections caused byStaphylococcus aureus.Such infections include impetigo, angular cheilitis (an infection around the mouth), and infected dermatitis. It works by stopping the growth of the bacteria causing the infection.

Fusidic acid resistance inS. aureuscan be readily selected for by in vitro exposure to the antibiotic, leading to the recommendation that for systemic therapy fusidic acid should only be given in combination with another agent. More controversial is the use of topical fusidic acid in the treatment of cutaneous and soft tissue infections.

Increasing fusidic acid resistance inStaphylococcus aureusmight be important for three reasons. First, it might mean that systemic fusidic acid can no longer be used in situations where it is clinically indicated. Second, failure of topical treatment may occur, especially in primary care settings where treatment is often empiric. Third, resistance to fusidic acid might be linked to other antibiotic resistances, therefore favoring spread of multiply antibiotic resistantStaphylococcus aureussuch as MRSA (methicillin-resistantS. aureus).

Mupirocin is a topical antibiotic used to treat superficial skin infections and to control the spread of methicillin-resistantStaphylococcus aureus(MRSA). Mupirocin resistance was observed shortly after it became available. Prevalence of mupirocin resistance among MRSA isolates has been described mostly in hospitalized adult and elderly patients with wide variability, ranging from 0 to 65% of isolates. Rates of resistance have been shown to correlate with increased use in closed inpatient settings. Very restrictive mupirocin prescriptions for local treatment are now recommended.

Impetigo is a highly contagious bacterial infection of the superficial layers of the epidermis. Impetigo is one of the most common skin diseases among children, accounting for about 10% of skin diseases treated in US paediatric clinics. The bacteria typically considered to be responsible areStaphylococcus aureusandStreptococcus pyogenes,and often a combination of the two. Impetigo is usually transmitted by direct contact but fomites also play an important role. Methicillin-resistantStaphylococcus aureus(MRSA) is being found with increasing frequency as a causative bacteria of impetigo. Impetigo has three common clinical varieties: impetigo contagiosa (common impetigo), bullous impetigo, and ecthyma. Features of all three types of impetigo, however, may coexist in any individual patient.

A number of topical compositions containing pharmaceutically active ingredients are known for the treatment of impetigo. Topical mupirocin 2% (Bactroban ointment and cream) is a treatment option, as arc older treatments, such as topical gentian violet and vioform. For many patients, mupirocin is a viable treatment option for MRSA, however, resistance of bacteria to mupirocin has been widely reported.

Topical fusidic acid 2% (Fucidin cream) is used for treatment of impetigo, and is thought to be equally as effective as mupirocin. However, the utility of fusidic acid for treatment of impetigo is limited by the problem of resistance development, as discussed above.

Fusidic acid-resistantStaphylococcus aureus(FRSA) has been identified as a causative bacteria in outbreaks of impetigo and its emergence has been associated with increased use of topical fusidic acid. Accordingly, utility of fusidic acid as first-line agent for the treatment of impetigo is questionable due to current resistance levels in the target bacteria. Retapamulin 1% (Altabax ointment), recently approved by the FDA, is a drug in the new class of pleuromutilin antibiotics for the topical treatment of impetigo due toStaphylococcus aureus(methicillin-susceptible only) orStreptococcus pyogene.

A wound is an injury to the body (as from violence, accident, or surgery) that typically involves laceration or breaking of a membrane (as the skin) and usually damage to underlying tissues (Merriam Webster Dictionary). Burns are injuries to tissues caused by heat, friction, electricity, radiation, or chemicals. Wounds and burns are often colonized by microbiologic pathogens, including Gram-positive bacteria, such asStaphylococcus aureusand/orStreptococcus pyogenes;and Gram-negative bacteria, e.g.Pseudomonas aeruginosa.

Despite the very common occurrence of skin infections, only a limited number of topical antibiotics are approved for the treatment of wounds and particularly infected wounds. Mupirocin (Bactroban) is an antibiotic, developed by GSK. Emerging resistance to mupirocin is becoming a concern. In coagulase-negative staphylococci isolates, mupirocin resistance rates are higher, ranging from 12.7% in Europe to 38.8% in the United States. Retapamulin (Altabax, GSK) is another topical antibiotic used for wound treatment. Fucidin (LEO Pharma) is also effective in primary and secondary skin infections caused by sensitive strains ofStaphylococcus aureus, Streptococcusspecies andCorynebacterium minutissimum.

Bacterial infections are a leading cause of death worldwide, and bacterial resistance is greatly reducing available treatment options. There is therefore a need for new antibiotics, for which development of resistance is not widespread in the target bacteria, for the prevention and treatment of topical infections caused or contributed to Gram-positive bacteria such asStaphylococcus aureusandStreptococcus pyogenesis strongly warranted.

The halogenated salicylanilides are a series of compounds generally used as anthelmintic agents. One such compound is niclosamide (5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydroxybenz-amide; also known as 2′,5-dichloro-4′-nitrosalicylanilide, 2-hydroxy-5-chloro-N-(2-chloro-4-nitrophenyl)-benzamide, 5-chloro-2′-chloro-4′-nitrosalicylanilide or 5-chloro-N-(2-chloro-4-nitrophenyl)-salicylamide):



Acute toxicity of niclosamide:LD50, mice, p.o., >5000 mg/kgLD50, rats, p.o., 5000 mg/kgLD50, rats, dermal, 2000 mg/kgLD50, rabbits, p.o., 5000 mg/kgLD50, cats, p.o., >1000 mg/kg

Niclosamide is a known taenicide (=tapeworm killer) effective against several parasitic tapeworms of livestock and pets (e.g.Taeniaspp,Monieziaspp) and also against rumen flukes (Paramphistomumspp) and blood flukes (Schistosomaspp). This is in contrast with most other salicylanilides, which generally exhibit activity as flukicides but not as taenicides.

Niclosamide is currently used in humans as an anthelmintic drug to treat intestinal infections and displays overall low toxicity, it is poorly soluble in water, shows low intestinal absorption, and once in the bloodstream, it is quickly cleared via the urinary tract or by enzymatic metabolism in the liver. Therapeutically it is useful against cestoda in humans.

Niclosamide has also been shown to prevent the penetration ofSchistosoma mansonithrough the human skin. As well as used as an anticancer drug, pesticide and as an anti-trypanosoma drug. Virtually all applications and proposed applications of niclosamide target eukaryotic organisms.

Niclosamide has also been shown to inhibit viral replication in human cells. However, the mechanism is believed to be through targeting human host cells to provide conditions that prevent the viral life rather than specifically targeting the virus. Accordingly, the viral application of niclosamide result from its ability to target an eukaryotic process.

Niclosamide is commercially available in a number of formulations including, but not limited to Bayer73®, Bayer2353®, Bayer25648®, Bayluscid®, Baylucide®, Cestocid®, Clonitralid, Dichlosale®, Fenasal®, HL 2447®, Iomesan®, Iomezan®, Manosil®, Nasemo®, Niclosamid®, Phenasal®, Tredemine®, Sulqui®, Vermitid®, Vermitin® and Yomesan®.

Other halogenated salicylanilide compounds areClosantel, (N-[5-chloro-4-[(4-chlorophenyl)cyanomethyl]-2-methylphenyl]-2-hydroxy-3,5-diiodobenzamide) is used as a veterinary anthelmintic:



Acute toxicity of closantel:LD50, rats, p.o., 262-342 mg/kg (depending on the study), median 302 mg/kgLD50, rats, s.c., 67 mg/kgLD50, mice, p.o., 331 mg/kgLD50, mice, i.m., 57 mg/kgRafoxanide (3′-chloro-4′-(p-chlorophenoxy)-3,5-diiodosalicylanilide) is known for veterinary use as a fasciolicide and anthelmintic.



Acute toxicity of rafoxanide:LD50, rats, p.o., 980->2000 mg/kg (depending on the study), median >1490 mg/kgLD50, mice, p.o., 232-300 mg/kg (depending on the study), median 266 mg/kgLD50, rabbits, p.o., 3200 mg/kgOxyclozanide (3,3′,5,5′,6-pentachloro-2′-hydroxysalicylanilide), is known for veterinary use as an anthelmintic, primarily against trematodes.

LD50, rats, p.o., 980-3519 mg/kg (depending on the study), median 2250 mg/kgLD50, mice, p.o., 300 mg/kgLD50, rabbits, p.o., 3200 mg/kgLow safety margin after oral administration

The molecular mode of action of salicylanilides, including niclosamide, is not completely elucidated. They all are uncouplers of the oxidative phosphorylation in the cell mitochondria, which disturbs the production of ATP. This impairs the parasites motility and probably other processes as well. Niclosamide acts on the tapeworms also through inhibition of glucose absorption

Niclosamide has been proposed as a possible systemic treatment for chronic lung infections caused by the proteobacteriumPseudo-monas aeruginosaand the actinobacteriumMycoplasmum tuberculosis.Niclosamide has been shown to reduce the quorum sensing response as well as the production of quorum sensing metabolites inP. aeruginosa.Since quorum sensing is considered an important process for the pathogenicity during chronic lung infections caused by this bacterium, it led to proposal that niclosamide could be used as an adjuvant therapy for these infections. Niclosamide does not affect the growth ofP. aeruginosaand accordingly does not have any direct antibacterial activity. The concentration required for optimal activity was 20 μM, however, some inhibition was detected at 1 μM. (F. Imperi et al., Antimicrobial, Agents and Chemotherapy, 557(2), 996-1005 (2013)).

Ghazi et al. (Zentralbl. Mikrobiol. 141 (1986), 225-232) tested the antibacterial effect and toxicity of synthesized salicylanilide derivatives againstEscherichia coli, Bacillus subtilis, Pseudomonas aeruginosaandStaphylococcus aureusbut nothing is mentioned about the rate of resistance development.

J. Vinsova et al. describe the antibacterial activity of salicylanilides (Molecules,vol. 12, no. 1, pp. 1-12, 2007;Bioorganic and Medicinal Chemistry Letters,vol. 19, no. 2, pp. 348-351, 2009;European Journal of Medicinal Chemistry,vol. 45, no. 12, pp. 6106-6113, 2010), but nowhere mentioned the problem with resistance development.

M. J. Macielag et al. tested the antibacterial activity of closantel and related derivatives against the drug-resistant organisms, methicillin-resistantStaphylococcus aureus(MRSA) and vancomycin-resistantEnterococcus faecium(VREF) (J. Med. Chem., 41(16), 2939-45 (1998)) but nowhere mentioned the problem with resistance development.

D. J. Hlasta et al found that closantel had antibacterial activity against drug resistantS. aureusandE. faecium(Bioorg. Med. Chem. Letters, 8(14), 1923-28 (1998)), but nowhere mentioned the problem with resistance development.

R. Rajamuthiah et al. identified closantel as a hit in a high throughput liquid screening assay and found anti-staphylococcal activity of closantel against vancomycin-resistantS. aureusisolates and other Gram-positive bacteria. There is no mention of the problem of resistance development (PloS One, 2014, 9(2): e89189).

WO 2008/155535 describes the use of halogenated salicylanilides for the treatment of acne, wherein propionibacteria is the bacteria causing the acne. There is no mention of the problem with resistance development.

SUMMARY OF THE INVENTION

Many bacteria are resistant to, or rapidly develop, resistance against antibiotic agents and thus it is undesirable or ineffective to treat a mammal suffering from a topical bacterial disease or infection caused by bacteria that are resistant to the antibiotics. Described herein is the topical use of a halogenated salicylanilide for the treatment of an infection caused by Gram positive bacteria. The topical use of the halogenated salicylanilides according to the invention have a substantially reduced frequency of spontaneous resistant mutants compared to commonly used topical antibiotics.

In a first aspect of the invention there is provided a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters for use in topical prevention or treatment of an infection or disease caused by Gram positive bacteria, wherein the Gram positive bacteria is not a propionibacteria. The invention thus provides a method of treating a disease or infection caused by Gram positive bacteria in a subject, the method comprising topically administering to the subject an effective amount of a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters; wherein the Gram positive bacteria is not a propionibacteria.

In a second aspect of the invention there is provided a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters for use in the topical prevention or treatment of an infection or disease by Gram-positive bacteria which is resistant to a drug selected from fusidic acid, mupirocin and retapamulin. The invention thus provides a method of treating or preventing a disease or infection caused by Gram positive bacteria in a subject, the method comprising topically administering to the subject an effective amount of a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters; wherein the Gram-positive bacteria which is resistant to a drug selected from fusidic acid, mupirocin and retapamulin.

In a third aspect of the invention there is provided a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters for use in topical prevention or treatment of an infection or disease for which fusidic acid, mupirocin or retapamulin was an approved treatment in Europe on 12 Sep. 2014; wherein the disease or infection is caused by Gram positive bacteria. Similarly, the invention may provide A method of treating or preventing a disease or infection caused by Gram positive bacteria in a subject, the method comprising topically administering to the subject an effective amount a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters; wherein the infection or disease is an infection or disease for which fusidic acid, mupirocin or retapamulin was an approved treatment in the US on 12 Sep. 2014; and wherein the disease or infection is caused by Gram positive bacteria.

The inventors have found that the halogenated salicylanilides closantel, rafoxanide, oxyclozanide, or niclosamide or a pharmaceutically acceptable derivative thereof are highly effective against Gram-positive bacteria, such asStaphylococcus aureusandStreptococcus pyogenesand unexpectedly are also very effective in reducing the development of resistance bacteria, such as those mentioned above. The compounds are expected to be very useful topical agents for use in the prevention and/or treatment of diseases or infections. One specific halogenated salicylanilide is niclosamide. Examples of diseases which may be treated by topical administration of the halogenated salicylanilide include impetigo, bacterial conjunctivitis, atopic dermatitis related infections, nasal eradication, sycosis barbae, superficial folliculitis, paronychia erythrasma, secondary infected dermatoses, carbuncles, furonculosis (ecthyma, cellulitis, erysipelas, necrotising fasciitis, secondary skin infections of wounds, dermatitis, scabies, diabetic ulcers and the like).

In one embodiment the active ingredient is niclosamide or a derivative thereof or as a hydrate thereof such as niclosamide monohydrate, or salt thereof such as its ethanolamine salt, or piperazine salt or other suitable salts or hydrates of such salts.

Niclosamide is bacteriostatic forS. aureus(SeeFIG. 1), i.c. it prevents the growth, but does not kill the bacterium. Surprisingly, niclosamide has been found to have equally good effect onS. aureusstrains resistant to methicillin, fusidic acid and mupirocin as non-resistant strains (SeeFIG. 2). Biological testing (inter alia) has also unexpectedly revealed that the halogenated salicylanilides, and particularly niclosamide have lower mutation rate against MRSA 01 than compounds like fusidic acid, mupirocin and retapamulin (see Table 4).

Without wishing to be bound by a particular theory, it is believed that a number of niclosamide analogs can act in a manner similar to niclosamide. Illustrative niclosamide analogs include, but are not limited to closantel (CAS #: 57808-65-8), oxyclozanide (CAS #: 2277-92-1), rafoxanide (CAS #: 22662-39-1), clioxanide (CAS #: 14437-41-3). Other suitable niclosamide analogs include brotianide (CAS #: 23233-88-7), 4′-chloro-3-nitrosalicylanilide, 4′-chloro-5-nitrosalicylanilide, 2′-chloro-5′-methoxy-3-nitrosalicyl-anilide, 2′-methoxy-3,4′-di-nitrosalicyl-anilide, 2′,4′-dimethyl-3-nitrosalicylanilide, 21-chloro-3,4′-dinitrosalicylanilide, 2′-ethyl-3-nitrosalicylanilide, 2′-bromo-3-nitrosalicyl-anilide, and the like (EP2049137). It is noted that these niclosamide analogs are intended to be illustrative and not limiting, Methods of making niclosamide analogs arc well known to those of skill in the art (see, e.g. WO 2004/006906), which is herein incorporated by reference for all purposes.

It may be that the halogenated salicylanilide is selected from closantel, rafoxanide, oxyclozanide, niclosamide, clioxanide, brotianide, 4′-chloro-3-nitrosalicylanilide, 4′-chloro-5-nitrosalicylanilide, 2′-chloro-5′-methoxy-3-nitrosalicyl-anilide, 2′-methoxy-3,4′-di-nitrosalicyl-anilide, 2′,4′-dimethyl-3-nitrosalicylanilide, 2′-chloro-3,4′-dinitrosalicylanilide, 2′-ethyl-3-nitrosalicylanilide and 2′-bromo-3-nitrosalicyl-anilide, or a pharmaceutically acceptable salt or solvate thereof.

It may be that the halogenated salicylanilide is selected from closantel, rafoxanide, oxyclozanide and niclosamide, or a pharmaceutically acceptable salt or solvate thereof.

It may be that the halogenated salicylanilide is selected from closantel, rafoxanide and oxyclozanide, or a pharmaceutically acceptable salt or solvate thereof.

It may be that the halogenated salicylanilide is niclosamide, or a pharmaceutically acceptable salt or solvate thereof. It may be that the halogenated salicylanilide is niclosamide in the free-base form of the compound. It may be that the halogenated salicylanilide is a pharmaceutically acceptable salt of niclosamide.

In a fourth aspect of the invention there is provided a topical pharmaceutical formulation comprising a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters, wherein the components of the formulation are selected such that it provides a local pH of less than 6 at the site of infection.

The inventors have found that the antibacterial activity of halogenated salicylanilides, e.g. niclosamide, is higher at low pH than at neutral or basic pH. It may be that the formulation does not comprise a buffer or pH modifier. This can mean that the formulation does not significantly alter the naturally low pH of the skin at the site of infection.

It may be that the halogenated salicylanilide, e.g. niclosamide, is in the form of a free base. Halogenated salicylanilides are typically mildly acidic, comprising as they do phenolic groups. Salts of halogenated salicylanilides are typically formed with amines (e.g. ethanolamine) which can provide an increase in local pH.

Bacterial decolonisation may be an effective strategy for reducing the incidence of nosocomial (hospital acquired) infections, particularly those associated with MRSA. Many people carry MRSA without symptoms. Decolonising such patients may be beneficial in the prevention of the spread of MRSA in a hospital environment or to reduce the risk of the patient developing an infection following a surgical or medical procedure in hospital.

In a fifth aspect of the invention there is provided a method of treating, preventing or eliminating bacterial colonization by Gram positive bacteria in a subject, the method comprising topically administering to the subject an effective amount a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters. Thus, the invention may provide a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters, for use in treating, preventing or eliminating bacterial colonization in a subject by Gram positive bacteria by topical administration.

It may be that the halogenated salicylanilide is topically administered to the subject prior to performing a surgical procedure on the subject. It may be that the halogenated salicylanilide is administered to the nose of the subject, either intranasally or to the external skin of the nose. Thus it may be that the halogenated salicylanilide is topically administered to the nose of the subject to performing a surgical procedure on the nose or face of the subject.

It may be that the Gram-positive bacteria develops spontaneous mutations which confer resistance to the halogenated salicylanilide at a frequency of less than 10−6at the minimum inhibitory concentration (MIC) of the halogenated salicylanilide to the Gram positive bacteria. It may be that the Gram-positive bacteria develops spontaneous mutations which confer resistance to the halogenated salicylanilide at a frequency of less than 10−7at the MIC of the halogenated salicylanilide to the Gram positive bacteria. It may be that the Gram-positive bacteria develops spontaneous mutations which confer resistance to the halogenated salicylanilide at a frequency of less than 10−8at the MIC of the halogenated salicylanilide to the Gram positive bacteria. Thus, it may be that the Gram-positive bacteria develops spontaneous mutations which confer resistance to the halogenated salicylanilide at a frequency of less than 4×10−9at the MIC of the halogenated salicylanilide to the Gram positive bacteria.

It may be that the Gram positive bacteria is not a propionibacteria. It may be that the Gram positive bacteria is selected fromStaphylococcus aureusorStreptococcus pyogenes.It may be that the bacteria is resistant to a drug selected from fusidic acid, mupirocin and retapamulin. It may be that the bacteria is methicillin-resistantStaphylococcus aureus(MRSA).

It may be that the infection or disease is selected from the group consisting of impetigo, bacterial conjunctivitis, atopic dermatitis and related infections, infected eczema, rosacea, nasal eradication, sycosis barbae, superficial folliculitis, paronychia erythrasma, secondary infected dermatoses, carbuncles, furonculosis, ecthyma, cellulitis, erysipelas, necrotising fasciitis, secondary skin infections of wounds, dermatitis, scabies and diabetic ulcers. Thus it may be that the infection or disease is selected from the group consisting of impetigo, bacterial conjunctivitis and atopic dermatitis. It may be that the infection or disease is selected from the group consisting of impetigo, bacterial conjunctivitis, atopic dermatitis related infections, nasal eradication, sycosis barbae, superficial folliculitis, paronychia erythrasma, secondary infected dermatoses, carbuncles and furonculosis (ecthyma, cellulitis, erysipelas, necrotising fasciitis, secondary skin infections of wounds, dermatitis, scabies, diabetic ulcers and the like).

It may be that the infection or disease is not acne vulgaris.

It may be that the treatment is administered topically for 2 weeks or less.

It may be that the halogenated salicylanilide is comprised in a formulation the components of which are selected such that it provides a local pH of less than 6 at the site of infection. The inventors have found that the antibacterial activity of halogenated salicylanilides, e.g. niclosamide, is higher at low pH than at neutral or basic pH. Thus, it may be that the formulation does not comprise a buffer or pH modifier. Thus, it may be that the halogenated salicylanilide, e.g. niclosamide, is in the form of a free base. The components of the formulation may be selected such that it provides a local pH of greater than 4.5 (e.g. greater than 5) at the site of infection. Reference to a “local pH” is to the pH at the site where the formulation is applied for example the pH on the surface of the skin after applying the formulation containing the halogenated salicylanilide.

It may be that halogenated salicylanilide is selected from rafoxanide, oxyclozanide, closantel and niclosamide and derivatives thereof including salts, hydrates and esters. It may be that halogenated salicylanilide is selected from rafoxanide, oxyclozanide and niclosamide and derivatives thereof including salts, hydrates and esters. Thus, it may be that the halogenated salicylanilide is niclosamide or a salt or hydrate thereof.

It may be that the halogenated salicylanilide (e.g. rafoxanide, oxyclozanide, closantel or niclosamide) is in the form of a free base. It may be that the halogenated salicylanilide (e.g. rafoxanide, oxyclozanide, closantel or niclosamide) is not in the form of a hydrate. Where the halogenated salicylanilide is niclosamide it may be that it is not in the form of the monohydrate.

It may be that the Gram-positive bacteria is not an antibiotic resistant strain. Alternatively, it may be that the Gram-positive bacteria is an antibiotic resistant strain.

It may be that the infection or disease is in a human or animal, for example wherein the infection is in a human.

In some embodiments, the population of Gram-positive bacteria includes antibiotic-resistant Gram-positive bacteria.

It may be that the Gram positive bacteria is not a propionibacteria, e.g. that it is notPropionibacterium acnes.

In some embodiments, the population of Gram-positive bacteria includes coccus gram-positive bacteria. In some embodiments, the Gram-positive bacteria are from theStreptococcusorStaphylococcusgenus.

In some embodiments, the Gram-positive bacteria are from theStreptococcusgenus. It may be that the Gram-positive bacteria areStreptococcusselected fromStreptococcus pneumoniae, Streptococcus pyogenes, Streptococcus suis, Streptococcus agalactiaeorStreptococcus viridans.

In some embodiments, the Gram-positive bacteria areStreptococcus pyogenes

In some embodiments, the Gram-positive bacteria are from theStaphylococcusgenus. It may be that the Gram-positive bacteria areStaphylococcusselected fromStaphylococcus epidermidis, Staphylococcus aureus, Staphylococcus saprophyticusorStaphylococcus lugdunensis.In some embodiments, the coccus Gram-positive bacteria areStaphylococcus aureus(e.g. methicillin-resistantStaphylococcus aureus).

The Gram-positive bacteria described herein may be resistant to another antibiotic drug. For example, the bacteria may be resistant to another antibiotic drug other than a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and or niclosamide, or a derivative thereof. It may be that the bacteria is resistant to a drug selected from fusidic acid, mupirocin and retapamulin.

Also provided are methods of treating a subject having a Gram-positive bacterial infection that include topically administering to a subject having a Gram-positive bacterial infection one of the halogenated salicylanilides closantel, rafoxanide, oxyclozanide, or niclosamide or a derivative thereof in amounts sufficient to decrease the population of Gram-positive bacteria in the subject. The invention may be and characterized by a rate of developing spontaneous resistance to these bacteria of less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide.

Furthermore, the present invention provides a method of treating a subject suffering from an infection contributed to or caused by Gram-positive bacteria as hereinbefore described, said method comprising the step of topically administering an effective amount of a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide, or a derivative thereof. The invention may be characterized by a rate of developing spontaneous resistance to these bacteria of less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide which may be characterized by a rate of developing spontaneous resistance to these bacteria of less than 10−8, such as less than 4×10−9.

The present invention may provide the use of a pharmaceutically effective amount of a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide or a derivative thereof in the preparation of a medicament for use in the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis. The invention may be characterized by a rate of developing spontaneous resistance to these bacteria of less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide.

The present invention may provide a method for the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis comprising administering to a subject a pharmaceutically effective amount of a halogenate salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide or a hydrate or a salt or a hydrate of such a salt thereof. The invention may be characterized by a rate of developing spontaneous mutation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide.

The present invention may provide a method for the topical treatment of antibiotic-resistant Gram-positive bacterial infections comprising administering to a subject infected with antibiotic-resistant Gram-positive bacteria selected from the group consisting of antibiotic-resistantStaphylococcus aureusand/orStreptococcus pyogenes,a pharmaceutically effective amount of a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide or a hydrate or a salt or a hydrate of such a salt thereof. One example which is of special interest is niclosamide.

The present invention may provide a method for the prevention and/or treatment of conjunctivitis and keratitis caused by Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescomprising topically administering to a subject a pharmaceutically effective amount of a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide or a hydrate or a salt or hydrate of such a salt thereof. One example which is of special interest is niclosamide.

The present invention may provide a pharmaceutical composition comprising a pharmaceutically effective amount of a halogenated salicylanilide selected from closantel, rafoxanide, oxyclozanide and niclosamide or a derivative thereof to be administered for the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis and characterized by a rate of developing spontaneous resistance to these bacteria of less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide.

The present invention may provide a pharmaceutical composition comprising a pharmaceutically effective amount of niclosamide or a derivative thereof to be administered for the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis and characterized by a rate of developing spontaneous mutation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9.

The present invention may provide a pharmaceutical composition comprising niclosamide as the active ingredient to be administered for the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis and characterized by a rate of developing spontaneous mutation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9.

Examples of diseases which may be topically treated using the halogenated salicylanilide include impetigo, bacterial conjunctivitis, atopic dermatitis related infections, nasal eradication, sycosis barbac, superficial folliculitis, paronychia erythrasma, secondary infected dermatoses, carbuncles, furonculosis (ecthyma, cellulitis, erysipelas, necrotising fasciitis, secondary skin infections of wounds, dermatitis, scabies, diabetic ulcers and the like).

The infection or disease treated topically using the halogenated salicylanilide may be a skin infection, infected dermatitis or infected dermatosis, for example any of the skin infections described herein. The skin infection may, for example, be selected from impetigo (including impetigo contagiosa, bullous impetigo, and ecthyma) infected dermatitis (for example infected atopic dermatitis) infected eczema, infected skin wounds, infected burns and infected ulcers (for example diabetic ulcers).

The infection or disease treated topically using the halogenated salicylanilide may be a secondarily Gram positive infected dermatosis, for example a secondary skin infection. Secondary Gram positive infections arc common complications of primary dermatoses, primary nonbacterial skin infections, traumatic lesions, ulcers, cutaneous infestations, and other skin diseases. Accordingly, the halogenated salicylanilide may be for use in the topical treatment of for example secondary infections of a condition selected from eczema, pediculosis, scabies, insect bites (for example papular urticaria), pemphigus psoriasis, skin ulcers, kerion and a viral infection of the skin (for example herpes simplex or chicken pox).

The halogenated salicylanilide may be for use to decolonise a subject carrying a Gram positive bacteria (including any of the Gram positive bacteria described herein, for example MRSA), wherein the halogenated salicylanilide is applied topically to the subject. Such decolonisation may be effective in preventing or reducing the spread of infection to other subjects particularly in a hospital environment. Decolonisation may also prevent or reduce the risk of surgical site infections resulting from surgical or medical procedures carried out on the patient or at the site of medical devices such as catheters or IV lines or cannula. Accordingly the halogenated salicylanilide may be for use in the decolonisation of a subject prior to carrying out a surgical procedure on the subject, wherein the halogenated salicylanilide is applied topically to the subject. Such surgical procedures include, for example elective surgical procedures such as hip or knee replacement. Decolonisation may be achieved by topically administering the halogenated salicylanilide to sites on the subject which are colonised by the Gram positive bacteria. It is known that a common site for bacterial colonisation such as MRSA is the nose. Accordingly, the halogenated salicylanilide may be applied topically to the nose. Particularly the halogenated salicylanilide may be applied to the anterior nares (the inner surface of the nostrils).

The infections and decolonisation described in the above paragraphs and herein may be topically treated with any of the halogenated salicylanilides herein selected from closantel, rafoxanide, oxyclozanide or niclosamide or a derivative thereof. Particularly the halogenated salicylanilide may be niclosamide.

The present invention may provide a pharmaceutical composition comprising a pharmaceutically effective amount of one of the halogenated salicylanilides closantel, rafoxanide, oxyclozanide or niclosamide or a derivative thereof to be administered for the topical prevention and/or treatment of Gram-positive bacteria such asStaphylococcus aureusand/orStreptococcus pyogenescolonizing or infecting skin affected with a dermatological condition selected from the group consisting of impetigo, atopic dermatitis and infections associated with different skin conditions such as eczema or psoriasis characterized by a rate of developing spontaneous mutation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9against MRSA 01, MRSA 15 and MRSA 16 at a concentration of MIC×1 when measured according to mutational frequency evaluation method as described in the experimental section. Niclosamide has been found to be superior againstS. aureusandS. pyogenes(both in μM and μg/ml).

A further aspect of the invention also provides a halogenated salicylanilide selected from the group consisting of closantel, rafoxanide, oxyclozanide, and niclosamide and derivatives thereof including salts, hydrates and esters for use in the topical prevention or treatment of an infection caused by Gram-positive bacteria, are highly effective in inhibiting the growth of Gram-positive bacteria such asStaphylococcus,in particularStaphylococcus aureus,andStreptococcus,in particularStreptococcus pyogenescharacterized by a rate of developing spontaneous mutation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9. One example which is of special interest is niclosamide.

A further aspect of the invention also provides a method for manufacturing of a medicament for use in topical prevention or treatment of an infection caused by Gram-positive bacteria, wherein the medicament is niclosamide and derivatives thereof including salts, hydrates and esters and wherein the use of the halogenated salicylanilide are highly effective in inhibiting the growth of Gram-positive bacteria such asStaphylococcus,in particularStaphylococcus aureus,andStreptococcus,in particularStreptococcus pyogenescharacterized by a rate of developing spontaneous imitation frequency less than 10−6, such as less than 10−7or 10−8, such as less than 4×10−9.

By the topical use of the halogenated salicylanilides, such as niclosamide it is possible to treat a human suffering from an infection caused by bacteria such asStaphylococcus aureusorStreptococcus pyogeneswhile having a reduced rate of appearance of spontaneous resistant mutants against the agent.

Further advantages and objects with the present invention will be described in more detail, inter alia with reference to the accompanying drawings.

