Record numbers of elderly people fell victim last year to a potentially lethal superbug which is plaguing Britain's hospitals, according to details of the first complete survey of the disease. Concerns about the bug, Clostridium difficile, were first revealed in The Independent in June following an outbreak of a lethal strain at Stoke Mandeville Hospital. The figures yesterday showed that there were 44,488 cases of the bug among people over 65.

The first published since reporting outbreaks became compulsory, the statistics show that the scale of the problem is greater than previously thought. A voluntary reporting scheme showed there were 35,536 cases of infection in 2003.

Cases in Britain had risen from about 1,000 in the early 1990s to more than 20,000 by 2000 and caused the death of nearly 1,000 people in 2003.

C difficile, which causes severe diarrhoea, has been spreading across NHS sites. Twelve people died during an outbreak of a lethal strain at Stoke Mandeville, which infected more than 300 patients. An outbreak at the Royal Devon and Exeter Foundation NHS Trust has caused 23 deaths since January this year.

Yesterday, the Department of Health said the increase in cases was due to better reporting and the increasing number of patients with serious conditions requiring antibiotics.

But union leaders blamed the rise on poor cleaning standards in hospitals and said the use of private-sector firms in the NHS had led to cuts in staff numbers.

Karen Jennings, head of health at the public service union Unison, said: "It's not rocket science. The way to wipe out these superbugs is to have cleaner hospitals and if you want cleaner hospitals you must have more cleaners. Cleaners are the front line of defence and yet contracting out has led to a drastic cut in the number of hospital cleaners. It's time to put that right.

Employ more cleaners, give them training and decent equipment and let them get on with the job of keeping our hospital wards, operating theatres and departments spotlessl . We can wipe out these superbugs and shake off the image of England as the superbug capital of Europe."

The Conservatives also went on the attack. Simon Burns, a shadow Health minister, said: "I am startled at the number of elderly people who have caught this superbug. People should be going to hospital to get better, not worse. The Government has poured money into the NHS but superbugs continue to proliferate. The first steps to cleaner hospitals are to scrap Labour's political targets and put matron in charge with the authority to shut dirty wards."

Christine Beasley, the chief nursing officer, said the Government had already issued guidance on dealing with outbreaks, including advice on using antibiotics and isolating patients. But she said the guidelines were being reviewed.

She said: "C difficile diarrhoea occurs in patients who have received broad-spectrum antibiotics, particularly the elderly and debilitated, but most patients make a full recovery. We have seen a rise in cases over the past decade, some of which is due to better reporting, but much of which is due to the increased number of patients with serious underlying illness who need antibiotics."

Gordon Lishman, director general of the charity Age Concern England said: "The very high rates of this appalling infection will worry many older people as they are the biggest users of the NHS and are most likely to be exposed to it. Collating and publishing these figures is a step forward, however high standards of hygiene are paramount. Many hospitals are not doing enough to keep the wards safe and clean."

* The number of people waiting for an NHS operation in England fell to its lowest level in 17 years, figures published yesterday show. The total waiting list stood at 813,700 at the end of July, the lowest since 1988. There were 40,700 patients waiting more than six months for an operation, although the figure fell 2,500 from June.