A two-time finalist in the Brazilian national Miss World contest died in hospital on Sunday after succumbing to a severe bacterial infection.

News reports stated her boyfriend as saying that model Mariana Bridi da Costa, 20, fell ill in Brazil on Dec 30 last year and was initially diagnosed by doctors as having kidney stones.

Further testing revealed, however, that she was infected with the pseudomonas aeruginosa bacterium.

Pseudomonas aeruginosa is a form of bacteria that is found widely in the soil, water and plants, said Dr Roland Jureen, a consultant with the Department of Laboratory Medicine at the National University Hospital.

He said the bacteria thrives in moist surroundings and can even be found in hospital environments, in areas like sinks and taps.

Sadly, by the time Ms da Costa was diagnosed with the infection, septicaemia had made its way into her limbs, cutting off circulation. Due to the severity of her condition, her hands and feet were amputated. She was in critical condition at a hospital in Espirito Santo, Brazil, for several days before her death.

As Ms da Costa had a rare blood type - O negative - her family appealed for donations.

It's a scary story though many details about the model's illness are not known. However, can this happen easily to anyone?

Dr Jureen said that while healthy people are rarely at risk of serious infections, patients in hospitals are more susceptible.

As an opportunistic pathogen (disease-producing agent), the bacteria takes advantage of breaks in its host's immune system, thus causing infection.

Those with compromised immunities - such as diabetics and cancer patients - are also more prone to infection.

Symptoms of pseudomonas aeruginosa infections are similar to those caused by other bacteria, said Dr Jureen.

As such, it is mainly detected through swab samples of a patient's urine, blood or phlegm which is then cultured, or grown, in hospital or clinic laboratories.

It can cause problems like urinary tract infections, pneumonia and wound infections, said Dr Jureen.

In rare instances, when the bacteria enters the bloodstream, it can also lead to septicaemia. This may have happened in the case of Ms da Costa, he said.

'It spreads by direct contact so normal hand hygiene like handwashing and using alcholic disinfectants have to be practised in hospitals,' he said.

In milder instances, the bacteria can also cause skin and and nail infections, said Dr Eileen Tan, a dermatologist in private practice.

This can lead to discolouration, nail-bed swelling and pus discharge in the finger and toe nails.

One problem with pseudomonas aeruginosa is that it is highly resistant to many common antibiotics, said Dr Khong Po Marn, a chest physician at Mount Elizabeth Hospital. He added that strains of the bacteria found in hospitals tend to be even more resistant. This can lead to severe pneumonia in patients and can even be fatal in some instances.

Treating the infection in time is another important issue, said Dr Khong.

This is because lab culture results take about 48 hours to be processed, during which time the bacteria can spread very quickly.

While antibiotics have proven to be effective in treating pseudomonas aeruginosa infections, there are times when even these fail to work.

'In rare cases, the bacteria can be resistant to all the drugs that are currently available and treatment then becomes very difficult,' said Dr Jureen.

This article was first published in Mind Your Body, The Straits Times on Jan 29, 2009.