Scientists say they believe as many as 53 million people may carry the superbug MRSA.

MRSA (Methicillin-Resistant Staphylococcus Aureus) is a nightmare for hospitals and nursing homes as it usually occurs in patients with weakened immune systems.

The scientists from the National Institute for Public Health and the Environment in the Netherlands, say the prevalence of the infection makes it the most commonly identified antibiotic-resistant pathogen in many parts of the world.

The superbug is a potential killer as it is resistant to certain antibiotics and can be spread by poor hygiene.

Scientists suggest that as many as 25-30 percent of the world’s population now have a form of the bacteria Staphylococcus Aureus.

MRSA is found on a regular basis in Europe, north and south America, north Africa, the Middle East, and east Asia.

Professor Hajo Grundmann, scientific co-ordinator of the European Antimicrobial Resistance Surveillance System (EARSS) says that even in countries such as the Netherlands, Sweden and Norway, where incidents of MRSA have been historically low, the rates are rising.

Grundmann, one of the authors of the study, says genetic changes in the superbug could well make it even more resistant to treatment and more virulent.

He says the onus is on health-care authorities to develop surveillance systems and provide the resources for early recognition of MRSA carriers through rapid screening.

Grundmann says hospital staff have a responsibility to implement, maintain, and adhere to strict contact precautions, and hospitals must remain places where citizens can confidently expect positive health-care outcomes.

MRSA has been an increasing problem in many countries in recent years and a survey recently revealed that UK patients were far more worried about catching MRSA than about delays in treatment.

According to the Office for National Statistics the number of deaths linked to MRSA jumped 22% between 2003 and 2004 in the UK; the superbug kills between 5,000 and 20,000 patients every year in the UK.

The research is published in the current issue of The Lancet.