Microbiological study of the circulating bath system at Syowa Station

Abstract

Background; The circulating bath is known to have the potential to allow growth of microorganisms including pathogenic bacteria such as Legionella. Legionellosis, which causes severe pneumonia, may be difficult to manage in the Antarctic winter season. JARE-39 (1998-1999) and -40 (1999-2000) did microbiological studies of Syowa Station's circulating bath. Methods; Water samples including bath sink, water supplying outer tank, and filter of bath circulation system were collected and stored by freezing or in cold storage. After the samples were brought back to Japan, they were expamined to detect colonies of legionellae and other microorganisms; DNA testing to detect legionellae by PCR was also carried out. JARE-40 determined total counts of bacteria and Escherichia coli in the bath, and periodically measured the water temperature. Epidemiological analysis of bath-related diseases was done for JARE-39. Findings; Specimens from bath-water and filter of water-supply system showed positive result of the Legionella-specific DNA by PCR method. These samples, however, were all negative by the culture method for legionellae. Bath-water temperature in August exceeded 44.6℃ on average. By the end of the winter the water temperature came down 1 to 2 degrees, and then total counts of bacteria and E. coli were measured. During the winter season of JARE-39,outbreaks of gastroenteritis and upper respiratory illness occurred. Systematic microbiological and epidemiological surveillance in the station is necessary to prevent outbreaks of infectious diseases.