1. What is Clostridium Difficile?

Clostridium Difficile (C diff) is a bacterium which is the most common cause of antibiotic-associated diarrhoea.   C diff is found in soil and in both domestic and farm animals and is a normal finding in the bowel of about 5% of healthy adults and over 50% of infants and young children.   It does not cause disease in infants and young children, and in healthy adults, it does not cause disease so long as it and the other bacteria which normally occur in the healthy bowel are kept in balance.   If the balance is disturbed by the use of certain antibiotics, any C diff present can grow and infect the bowel, causing diarrhoea.

C diff forms spores in which the organism is covered in a shell-like coat which resists many means of killing bacteria, including heat, cold, alcohol and many disinfectants.   This allows C diff to survive in hostile environments.   It causes its harmful effects by producing toxins, chemicals which act on the lining of the bowel.

There are over 100 varieties of C diff, known as ribotypes as they differ in their genetic make up.    Ribotypes differ in their frequency and in the severity of disease they cause.   In the last decade, ribotype 027 has emerged, first in North America, and more recently in Europe and other parts of the world.    It was first identified in Northern Ireland in Antrim Area Hospital in June 2007, and was the most common ribotype found in the outbreak of C diff in Northern HSC Trust hospitals in 2007/08.   Ribotype 027 usually causes more severe disease and a higher mortality and is more readily spread.

C diff usually enters the human body through the mouth as a result of contaminated hands.    If the person has taken certain antibiotics, it may grow in the bowel and cause infection and diarrhoea.   Older people are most susceptible to disease from

C diff although it can, less commonly, occur in younger adults.    Thus the highest risk for C diff disease is a combination of exposure to infection, antibiotic treatment and old age.

C diff can cause diarrhoea, ranging from a mild disturbance to a very severe illness with ulceration and bleeding from the colon (colitis) and, at worst, perforation of the intestine leading to peritonitis. It can be fatal.   Fatalities are most common in frail older people who are already suffering from serious diseases.

Infection can be acquired anywhere C diff is present.   Most commonly it arises as a result of other infected people in hospitals and nursing homes.  Some patients are already infected when they enter the hospital.

Although some people can be healthy carriers of C.diff, in most cases the disease develops after ingestion of the bacteria from contaminated hands. A patient who has C diff diarrhoea excretes large numbers of bacteria in their liquid faeces. These can contaminate the general environment around the patient's bed (including surfaces, keypads, and equipment), the toilet areas, sluices, commodes, bed pan washers, etc. They can survive for a long time and be a source of hand-to-mouth infection for others. If these others have also been given antibiotics, they are at risk of C diff disease.

The spores of C diff are not killed by alcohol-based hand-washing gels.    Vigorous hand-washing with soap and water removes most of the spores.

A sample of diarrhoeal faeces is tested for the presence of the C diff toxins. This is the main diagnostic test and gives a result within a few hours. In outbreaks, or for surveillance of the different strains circulating in the population, ribotyping is performed. C diff is cultured from faeces and the isolates are sent to a specialist laboratory. This facility is now available in Northern Ireland at the Belfast City Hospital Laboratories.

The number of reported cases increased from less than 1,000 in the early 1990s to 22,000 in 2002, 28,000 in 2003 and 44,488 in 2004. Some of this is due to improved diagnostic tests and improved reporting by laboratories, but there has clearly been a very significant increase in the number of cases. Since January 2004, C diff has been part of the mandatory surveillance programme for healthcare associated infections.

There are four important components to the prevention and control of C diff disease: