Tigecycline data reveals MRSA efficacy
presented at this year's ECCMID conference, which showed the drug
demonstrated its efficacy against a wide variety of gram-positive
and gram-negative bacteria including multi-drug-resistant bugs.
Data presented at the show demonstrated that tigecycline monotherapy exhibited antibiotic activity against a wide range of bacteria commonly found in patients hospitalised in intensive care units worldwide including Staphylococcus aureus, Acinetobacter spp, and Klebsiella.
The data, presented at the >European Congress of ClinicalMicrobiology and Infectious Diseases (ECCMID), represents an importance on many different levels. As experts warn that 'the world may be running out of effective antibiotics,' statistics from pharmaceutical companies reveal that few new antibiotics have been developed in the last 20 years and there are very few in the pipeline currently.
The problem of growing resistance means that new broad-spectrum options are essential in the fight against MRSA and other hospital acquired infections
Tigecycline is a semi synthetic glycylcycline derived from the minocycline molecule. Tigecycline has documented activity against tetracycline-resistant gram-positive and gram-negative pathogens refractory by both efflux and ribosomal protection mechanisms.
Its mode of action on bacterial ribosomes shows identical and overlapping binding sites when compared to tetracycline, but the position 9 substitution of tigecycline provides additional steric hindrance features and resulting greater spectrum of activity.
Wyeth filed the submission for global regulatory approval for tigecycline at the end of last year (16th Dec 2004) with the FDA, EMEA and authorities in Canada and Australia. Approval is sought for tigecycline as a monotherapy to treat patients with complicated intra-abdominal infections (cIAI) and complicated skin and skin structural infections (cSSSI) caused by gram-negative and gram-positive pathogens, anaerobes and both methicillin susceptive and methicillin resistant strains of Staphylococcus aureus (MSSA and MRSA).
The urgent need for new antibiotic treatments has led to the FDA designating tigecycline priority review status. This status can only be given to those drugs, which if approved, would be a significant improvement compared with existing treatments.
According to a recent National Audit report from the UK MRSA rates are rising dramatically across Europe with the UK, Eire, Greece and Italy having the highest rates. Within these the proportion of MRSA rates is highest among patients admitted to intensive care units.
Patients hospitalised in the intensive care unit (ICU) are at particular risk for acquiring nososcomial infections. Exposure to various antimicrobial agents may further complicate such hospitalisation and create conditions that favour resistance selection among host bacterial flora or nosocomially transmitted pathogens. Thus, rates of antimicrobial resistance are generally higher in bacteria isolated from ICUs compared with other hospital wards and outpatient clinics
The prevalence of nosocomial infections caused by MRSA has been increasing for several years in many countries around the world. The US Centres for Disease Control and Prevention estimates that between 60,000 and 80,000 Americans die each year from nosocomial infections and the cause in the majority of cases is S. aureus.
Reports from the UK National Audit Office state that at any one time, 9 per cent of NHS hospital patients are suffering from an infection such as MRSA, acquired whilst in surgery or as an inpatient on the hospital wards. These 'nosocomial' infections affect 100,000 people annually, costing the National Health Service £1 billion (€1.5bn), and causing up to 5,000 deaths.
