||These organisms are some of the most important sources of infection in humans which can have a high fatality rate
||These organisms are quite resistant to many anti-microbial drugs and may cause severe infections in the reproductive system or the heart tissue as well as skin infections, wound infections, septicemia, heart disease, arthritis, pneumonia, violent nausea, vomiting and diarrhoea
||These bacteria may cause pneumonia, urinary tract infections and sepsis.
||These organisms can be found in soil and water, but are very often involved in human infections. The organisms were originally known as causes of respiratory diseases (especially pneumonia), but also encountered in hospital infections of the urinary tract. Klebsiella is one of the organisms causing outbreaks of disease in hospitals, especially in intensive care situations and infant wards.
||These organisms cause gastroenteritis and sepsis in immune-compromised people.
| Escherichia coli
||Their presence in the environment is usually used as an indicator of pollution with sewerage. E.coli is the most common cause of urinary tract infections and certain forms of sepsis in humans. It is also one of the two most important causes of meningitis in infants. Diarrhoea is prominent among the diseases caused by E.coli.
||These organisms infect hosts who have impaired immune systems such as person suffering from malnutrition, tuberculosis or those who are HIV positive. It is usually resistant to most of the commonly used antibiotics generally available. They are associated with urinary tract infections, meningitis, sepsis and pneumonia
||When present in immuno-compromised people, it may cause wound infections, meningitis, urinary tract infections and eye infections
| Proteus mirabilis and Proteus vulgaris
||These organisms are incriminated in summer diarrhoea in children.