Comparison of free-living amoebae in hot water systems of hospitals with isolates from moist sanitary areas by identifying genera and determining temperature tolerance.
Legionella-contaminated hot water systems and moist sanitary areas in six hospitals were sampled for amoebae by following a standardized collection protocol. Genus identifications and temperature tolerance determinations were made. Amoebae identified as Hartmannella vermiformis (65%), Echinamoebae spp. (15%), Saccamoebae spp. (12%), and Vahlkampfia spp. (9%) were detected in 29 of 56 (52%) hot water samples. Twenty-three of 49 (47%) swabs obtained from moist areas were amoeba positive. The following genera were identified: Acanthamoeba (22%), Naegleria (22%), Vahlkampfia (20%), Hartmannella (15%), and Vanella (7%). The temperature tolerance of amoebae from hot water systems was strikingly different from that of amoebae from moist areas. At 44 degrees C on agar, 59% of amoebic isolates sampled from hot water systems showed growth. The corresponding value for isolates from moist areas was only 17%. Six Acanthamoeba isolates from the moist areas were considered potential pathogens. Four Hartmannella and two Saccamoeba isolates from hot water could be cultured at 53 degrees C.
Rohr
U
U
Institut für Hygiene und Mikrobiologie, Ruhr-Universität Bochum, Germany. rohr@hygiene.ruhr-uni-bochum.de
Weber
S
S
Michel
R
R
Selenka
F
F
Wilhelm
M
M
D000048:Acanthamoeba / Q000302:isolation & purification; D000656:Amoeba / Q000302:isolation & purification* / Q000502:physiology; D000818:Animals; D006249:Hartmannella / Q000302:isolation & purification; D006761:Hospitals; D009253:Naegleria / Q000302:isolation & purification; D013696:Temperature; D014867:Water / Q000469:parasitology*
D014867:Water