A study at the University of Pittsburgh led by Victor L. Yu, MD, PhD, found that the water supply is a major culprit in hospital-acquired Legionnaires’ diseases, reports Infection Control and Hospital Epidemiology.

Of the 20 hospitals that were surveyed, 14, or 80%, tested positive for Legionella pneumophila and L. anisa, the two strains that cause the oftentimes-fatal form of pneumonia known as legionnaire’s disease. Of that amount, 30% had high-level colonization of the pneumophila strain in their water systems.

After 633 patients underwent testing of sputum and urine samples, four instances of hospital-acquired pnumophila-type Legionnaires’ disease were diagnosed. There were no instances of legionnaires’ caused by L. Anisa.

The researchers concluded that environmental monitoring followed by clinical surveillance was successful in uncovering previously unrecognized cases of hospital-acquired Legionella pneumonia.

In a separate study, also conducted at University of Pittsburgh and published in a subsequent issue of ICHE, the introduction of chlorine dioxide into the water system of a 364-bed hospital testing positive for pneumophila significantly lowered colonization rates. Zero cases of hospital-acquired Legionnaires’ disease were reported.

To read abstract, click here.