Woman Dies After Contracting Legionnaires' Disease From Dentist's Office

An 82-year-old Italian woman died after she contracted Legionnaires' disease, a severe, pneumonia-like illness, from the water in her dentist's office, according to a case report published in the journal The Lancet.

Scientists who determined the source of the woman's illness, which occurred in February 2011, said during the disease's incubation period the woman only left her home twice to visit her dentist.

When they tested the water in both places, they discovered the bacteria that causes Legionnaires' in the dentist's water line. Water lines carry water from the main water supply to certain devices used during patient care.

While the authors wrote the most common sources of infection are air conditioning systems, hot water systems, spas and fountains, a recent study found dental water lines to be another major source of contamination with Legionella bacteria. Legionella pneumophila is the bacterial strain that causes Legionnaires' disease.

"However, as far as we are aware, no case of Legionnaires' disease has been associated with this source of infection," added the authors, led by Maria Luisa Ricci of the Italian National Health Service.

While it was not clear what kind of water line standards were in place in Italy, in the U.S., the American Dental Association (ADA) said infection control standards are very stringent in order to prevent cases like the one in Italy from happening.

"Since the ADA convened a special task force in the mid-1990s focusing on infection prevention, there have been a number of recommendations made to treat the water and keep the number of bacteria down," said John Molinari, the ADA's spokesman on infection control, infectious diseases and allergic reactions.

The ADA recommends that dental water lines contain no more than 500 colony-forming units of bacteria per milliliter of water, the same limit recommended by the U.S. Centers for Disease Control and Prevention.

The ADA also recommends that dentists monitor water quality and maintain a water reservoir that is separate from the municipal water supply, as well as use filters that will keep microorganisms out of the water.

Legionella bacteria is one of the most common types of bacteria found in water.

"Legionella is found in old homes, shower heads and anywhere else there can be stagnant water," Molinari said.

Most dentists take the necessary precautions to protect their water lines from contamination, but Molinari said that the Italian case is an important reminder.

"This report sends the message that it can happen," he said.

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First case of Legionnaire's disease found at a dentist

Doctors on Friday reported the first known case of Legionnaire's disease, a rare infection usually linked to faulty air conditioning and hot-water systems, that was caused by a visit to the dentist.

The case report, published in The Lancet, describes an unnamed 82-year-old woman in Rome who was hospitalised with fever and breathing problems in February 2011.

Swiftly diagnosed with infection by the Legionella pneumophila germ, she died two days later of septic shock despite being given heavy doses of antibiotics.

During the two- to 10-day time it would have taken for the bacteria to incubate, the patient had only left her house twice, both times to attend appointments at the dentist.

Samples of water were taken from the dentist's tap, from the waterline -- the tube that supplies water to tooth scalers and handpieces used by the dentist -- and from the high-pressure pump supplying the waterline itself.

All three sources tested positive for L. pneumophila, but especially in water taken from the pump.

Genetic sequencing found that the germs there matched the bacteria which killed the patient. The bug turned out to be a particularly virulent sub-strain called Benidorm.

After cleaning with hydrogen peroxide solution and bleach, the water unit was free of contamination.

The case is unusual, as outbreaks of Legionnaire's disease are generally caused by air-conditioning systems, hot-water systems, spas and fountains that are not properly cleaned or maintained.

Warm temperatures and periods of water immobility provide a breeding ground for the bacteria. Distributed in fine droplets by a spray, the bacteria are then breathed in. Elderly people or individuals with poor immune systems are those most at risk.

Previous research has shown that dental waterlines can be contaminated by the germ, but this is the first known case where illness has occurred.

"As far as we are aware, no case of Legionnaire's disease has been associated with this source of infection," says the report, headed by Maria Luisa Ricci at the Istituta Superiore de Sanita in Rome.

"The case here shows that the disease can be acquired from a dental unit waterline during routine dental treatment. Aerosolised water from high-speed turbine instruments was most likely the source of the infection."

The case report puts down a series of recommendations, including use of filters, continuous circulation of disinfected water and using sterile water instead of tap water.

ri/mb

View the original article here

First case of Legionnaire's disease found at a dentist

Doctors on Friday reported the first known case of Legionnaire's disease, a rare infection usually linked to faulty air conditioning and hot-water systems, that was caused by a visit to the dentist.

The case report, published in The Lancet, describes an unnamed 82-year-old woman in Rome who was hospitalised with fever and breathing problems in February 2011.

Swiftly diagnosed with infection by the Legionella pneumophila germ, she died two days later of septic shock despite being given heavy doses of antibiotics.

During the two- to 10-day time it would have taken for the bacteria to incubate, the patient had only left her house twice, both times to attend appointments at the dentist.

Samples of water were taken from the dentist's tap, from the waterline -- the tube that supplies water to tooth scalers and handpieces used by the dentist -- and from the high-pressure pump supplying the waterline itself.

All three sources tested positive for L. pneumophila, but especially in water taken from the pump.

Genetic sequencing found that the germs there matched the bacteria which killed the patient. The bug turned out to be a particularly virulent sub-strain called Benidorm.

After cleaning with hydrogen peroxide solution and bleach, the water unit was free of contamination.

The case is unusual, as outbreaks of Legionnaire's disease are generally caused by air-conditioning systems, hot-water systems, spas and fountains that are not properly cleaned or maintained.

Warm temperatures and periods of water immobility provide a breeding ground for the bacteria. Distributed in fine droplets by a spray, the bacteria are then breathed in. Elderly people or individuals with poor immune systems are those most at risk.

Previous research has shown that dental waterlines can be contaminated by the germ, but this is the first known case where illness has occurred.

"As far as we are aware, no case of Legionnaire's disease has been associated with this source of infection," says the report, headed by Maria Luisa Ricci at the Istituta Superiore de Sanita in Rome.

"The case here shows that the disease can be acquired from a dental unit waterline during routine dental treatment. Aerosolised water from high-speed turbine instruments was most likely the source of the infection."

The case report puts down a series of recommendations, including use of filters, continuous circulation of disinfected water and using sterile water instead of tap water.

View the original article here