3 Legionnaire’s Disease Cases Investigated

It was after three of his leukemia patients suddenly developed pneumonia that hematologist Stephen J. Forman suspected that an unusual germ might be lurking at the City of Hope Medical Center in Duarte.

“Any time on our 11-bed unit when more than one patient has an uncharacterized case of pneumonia, the flags go up,” Forman recalled Thursday.

Specimens taken from the patients’ lungs were rushed to the lab. Forman then ordered powerful antibiotics for the three patients, all recent recipients of bone-marrow transplants. “I felt we needed to aggressively find out if we had something unique going on here,” Forman recalled.

Late Monday evening, Forman’s suspicions were confirmed: Legionnaire’s disease had struck again. All three patients had it.

“We think we have a problem, but it is not an epidemic,” Dr. Ralph Jung, the hospital’s acting medical director, said Thursday.

“Outbreaks like this occur sporadically, and they were right on top of it,” said Dr. Peter W. Kerndt, a federal Centers for Disease Control investigator who arrived Thursday at the hospital to help hospital and county health officials investigate the outbreak and decontaminate wards where the cases have occurred.

The Legionella bacteria are spread through the air, but not from person to person, and most people exposed to the bacteria do not become ill. The disease most commonly occurs as isolated cases, not in clusters. But when there is an outbreak, it can usually be traced to contamination of an air-conditioning system or a water system.

“The cooling system is the prime suspect at this point,” Kerndt said.

In addition to the three cases confirmed this week, City of Hope physicians are investigating a case that developed at the nationally known medical research center in March and two that developed in June. Those three patients died, two of other infections and one of multiple causes, despite antibiotic treatment for legionnaire’s disease, according to Forman.

Hospital officials Thursday said it is too soon to say whether the earlier cases are related to the current outbreak. Isolated cases develop at many hospitals, and a few such cases have occurred at the City of Hope in the past several years.

Two of three current legionnaire’s patients are making a good recovery, Forman said. The third, who also suffers from an unrelated life-threatening illness, is in an intensive-care unit.

After the lab confirmation, hospital officials evacuated the 34-bed ward in which the earlier cases developed, moving patients to an unoccupied floor of the 212-bed hospital. Plans are also being made to evacuate the bone-marrow unit this weekend.

The two wards where the legionnaire’s disease cases developed are in different parts of the hospital and have separate air-conditioning systems, factors that investigators must consider in determining whether all six cases are linked.

Details of the decontamination process, which will involve draining and then flushing the water and cooling systems with chemical solutions, were still being finalized late Thursday. “The measures being taken . . . are appropriate to terminate the outbreak at this point,” Kerndt said.

He predicted that it may take weeks to obtain the results of laboratory tests, such as cultures for the Legionella bacteria from the water and cooling systems. Officials hope that the results will pinpoint the areas of contamination.

Although physicians were surprised by this week’s cluster of legionnaire’s cases, their routine procedures in caring for critically ill bone-marrow transplant patients had pointed them in the right direction from the start.

Bone-marrow transplant patients are extremely vulnerable to many unusual types of pneumonia. Among the drugs the three patients were immediately given was erythromycin, which is used to treat legionnaire’s disease.

“We have to cover all the bases,” said Dr. Jan Geiseler, the infectious disease specialist who helped diagnose the cases. “We don’t always find out the cause of a pneumonia. When routine tests are negative, you have to consider legionnaire’s, even if there have been no previous cases of the disease in the hospital.”

Legionella bacteria were recognized to cause disease after 29 people died after an American Legion convention in Philadelphia in 1976.

There were 28 cases of legionnaire’s diagnosed in Los Angeles county in 1985. About 650 cases were diagnosed nationwide.

An outbreak of eight cases occurred among city workers in Norco in Riverside County this June. The workers apparently contracted the disease while repairing a broken water line.

In Los Angeles, a smoldering epidemic of legionnaire’s disease caused 201 cases at the Wadsworth Veterans Administration Medical Center between 1977 and 1981. There were 46 deaths, but the bacteria were a contributing factor in only half of these cases.