The occurrence of aerolysin-positive Aeromonas spp. and their cytotoxicity in Norwegian water sources.
OBJECTIVE
The aim of the study was to investigate the occurrence of Aeromonas spp. and their aerolysin status in Norwegian natural water sources.


RESULTS
Seventy-one samples from 33 Norwegian water sources were examined for the presence of Aeromonas spp. From most of the sample sites, the strains were isolated on blood-ampicillin-agar and Difco Aeromonas agar simultaneously. The majority of the samples (73/77) contained Aeromonas spp., with an average of 35-100 cfu 100 ml(-1). The highest counts were found in faecally-contaminated water. Using PCR, 445 isolates were screened for the presence of aerolysin, and 79% of them were found to be carriers of the aerolysin gene. A selection of the isolated strains was tested on Vero cell cultures and 83% of them showed cytotoxicity.


CONCLUSIONS
There is widespread occurrence of aerolysin-positive cytotoxic Aeromonas spp. in many different Norwegian natural waters, including drinking water sources.


CONCLUSIONS
The widespread occurrence of potentially-pathogenic Aeromonas spp. in the environment demands that these bacteria should not be ignored in drinking water supplies and in the food industry.
Ørmen Ø
The Norwegian School of Veterinary Science, Department of Pharmacology, Microbiology and Food Hygiene, Oslo, Norway. Oyvind.Ormen@veths.no
Østensvik Ø
D000333:Aeromonas / Q000302:isolation & purification* / Q000378:metabolism; D000818:Animals; D001427:Bacterial Toxins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D001681:Biological Assay; D002522:Chlorocebus aethiops; D005798:Genes, Bacterial; D007473:Ion Channels / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D009664:Norway; D016133:Polymerase Chain Reaction; D052899:Pore Forming Cytotoxic Proteins; D014709:Vero Cells; D014871:Water Microbiology
D001427:Bacterial Toxins; D007473:Ion Channels; D052899:Pore Forming Cytotoxic Proteins; C032676:aerolysin