Unclean equipment spread TB in hospitals DNA studies pointed to bronchoscopes in Md., S.C. facilities

October 01, 1997|By Jonathan Bor | Jonathan Bor,SUN STAFF

Medical sleuths using DNA fingerprinting have determined that poorly cleaned medical instruments were responsible for the spread of tuberculosis in two hospitals -- including one in Maryland.

Both cases involved the use of contaminated bronchoscopes, fiber-optic devices that are used to examine and take biopsies from patients' lungs and airways. Articles involving separate cases in Maryland and South Carolina were published in today's Journal of the American Medical Association.

In the Maryland case, a bronchoscope passed TB bacteria to a 68-year-old woman who was undergoing a cancer evaluation at "an urban hospital" two days after the instrument had been used on a 36-year-old woman with tuberculosis, according to the report in JAMA.

State health officials refused to provide information identifying the patients or the hospital, noting rules ensuring patient privacy in disease investigations. The case occurred more than a year ago.

Ordinarily, tuberculosis is spread through the air by people living or working in close quarters. But scientists at the Johns Hopkins School of Hygiene and Public Health, working on a statewide study of TB cases, began to suspect a different cause when they learned through DNA analysis that the two patients carried the identical strain even though they did not share living or work space.

Once the DNA match was made, investigators with the city and the state health department learned that the patients had only one thing in common -- the bronchoscope.

"They were, in fact, consecutive procedures done in the same hospital, by the same doctor in the same operating room," two days apart, said Dr. William Bishai, a Hopkins microbiologist.

In the South Carolina case, three people examined with the same bronchoscope in 1995 acquired a strain of TB that is highly resistant to seven front-line antibiotics -- making the disease extremely difficult to treat, according to Dr. Tray Agerton of the U.S. Centers for Disease Control and Prevention.

The cases are just the latest examples of infections being spread among patients in hospitals across the country. In recent months, attention has focused mainly on the spread of dangerous staphylococcus bacteria -- although hospitals also face problems with pertussis and other diseases.

In a JAMA editorial, two doctors said the TB cases should cause hospitals to take another look at procedures for cleaning instruments.

"The key message, in fact, is that hospitals and clinics cannot afford to trivialize the importance of routine and thorough cleaning of reusable parts of the bronchoscope," said Dr. Richard Wenzel and Dr. Michael B. Edmond of Virginia Commonwealth University Medical College.

Dr. Diane Dwyer, a Maryland health department epidemiologist, said the hospital here took steps to improve its infection-control procedures -- including the use of disposable tubing.

According to guidelines issued by the Association of Practitioners in Infection Control, bronchoscopes should be immersed in a chemical disinfectant for 45 minutes.

A bronchoscope is used to diagnose cancer, tuberculosis, lupus and other diseases that can affect the lungs. Sometimes, doctors use a bronchoscope to locate and remove foreign objects that children have inhaled into their lungs.

Hopkins scientists made the DNA "match" through a federally funded program in which they are trying to determine how each new case of tuberculosis in Maryland is spread.

Pub Date: 10/01/97

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