THE NEW ZEALAND MEDICAL JOURNAL

In October 2006 a patient in the Children’s Haematology Oncology Centre (CHOC) at Christchurch Hospital was diagnosed as having a Legionella infection. The patient had been admitted 19 days earlier having suffered a relapse of acute lymphoblast leucaemia while on a trip to USA where she had also been admitted. As a nosocomial infection was considered a possibility, the Infection Control Service initiated a series of normal environmental cultures (shower, water supply, etc), which showed negative results for Legionella. Because the patient gave a history of drinking water from the water-cooler in the CHOC ward, this water was cultured for Legionella, and 12×102 cfu / L of Legionella pneumophila serogroup 1 were isolated. Direct culture of the filter from the cooler grew L. pneumophila serogroup 1. The filter was investigated by flushing it with sterile water. This filtrate grew 6×105 cfu/L on a direct flush and 6×104 in a 100 ml flush. Thirteen other coolers filled via different filters than the positive water-cooler were investigated with negative results. Three months after the positive filter had been removed from use, the filter was cut in half and the charcoal granules were cultured for Legionella. L. pneumophila serogroup 1 was still isolated in a concentration of 102 cfu/g of granules (Figure 1)