Campylobacter jejuni in a Washington State Shellfish Growing Bed Associated With Illness.

Consumption of raw Pacific oysters ( Crassotea gigas ) harvested from a Washington State recreational shellfish bed were associated with illness. Illness occurred within 2 d of ingestion of a half-dozen shellstock oysters. Each oyster consist of approximately 20 g of meat. The duration of illness lasted 2 d. Routinely, Campylobacter species have been found in several shellfish beds in the Puget Sound Bay. Its presence in the marine environment appears to be incidental and primarily, comes from wild birds, farm runoff, and sewage bypasses. This paper describes the first reported case of Campylobacter gastroenteritis associated with raw oyster consumption in the State of Washington.

Incidence of Motile Aeromonads From United States West Coast Shellfish Growing Estuaries.

The distribution of motile Aeromonas species in marine and tributary waters, sediment, and shellfish from 12 major estuarine areas in Washington, Oregon, and California with commercial or sport shellfish harvest was determined during the summer months. Aeromonas spp. were found in half of the total of 400 samples analyzed. Two enrichment broths, tryptic soy ampicillin broth (TSBA) and alkaline peptone water (APW), were compared for recovery of Aeromonas from Washington and Oregon samples. More Aeromonas were isolated using TSBA. For Washington and Oregon samples, recoveries using TSBA were 82 and 77% respectively compared to 31 and 50% using APW. For California samples, only APW was used with 28% samples positive. Of 767 isolates tested, 93.5% were positive for hemolysis, a trait reported to correlate with enterotoxin production and pathogenicity. Of the hemolysis positive strains, 59.5% were toxic to Y-1 adrenal cells.

Enumeration of Vibrio Species, Including V. cholerae , from Samples of an Oyster Growing Area, Grays Harbor, Washington.

Water, shellfish, and sediment samples from Grays Harbor, a major commercial oyster producing estuary in the State of Washington, were examined for levels of Vibrio species. Non-01 V. cholerae was found at low levels in 37.8% of the samples. While V. parahaemolyticus was found in all samples, levels were low. V. mimicus and V. fluvialis were found infrequently and at low levels. Potentially pathogenic strains of non-01 V. cholerae and Kanagawa positive V. parahaemolyticus were isolated from oysters suggesting a potential for human illness.

Microbiological Quality of Oysters ( Crassostrea gigas ) and Water of Live Holding Tanks in Seattle, WA Markets.

Oyster ( Crassostrea gigas ) and water samples from Live Holding Tanks at five different Seattle area retail markets were analyzed for microbiological quality indicators and for potential pathogens monthly from March to September, 1987. Aeromonas hydrophilia was the most frequently isolated potential pathogen in this study with a higher incidence in oysters (78%) compared to water (53%). Vibrio cholerae non 01 and V. fluvialis were isolated from oyster samples from two different markets but not from water. V. alginolyticus was isolated from 53% of the water samples but was not found in any of the oysters. One oyster sample had a non-pathogenic Yersinia entercolitica . Yersinia spp. were isolated from oyster samples from one tank at two sampling periods. Salmonella typhimurium was isolated from one oyster sample. Samples were examined for Listeria spp. during the August sampling period and none were detected. The aerobic plate count was similar for both oyster and water samples and averaged 2000 CFU/gm. Total coliform levels were significantly higher (P<.05) for oysters (525MPN/100gm) compared to water (11MPN/100ml). The degree of water turbidity, crowding and species diversity varied between markets and sampling periods.

Aeromonas hydrophila in Shellfish Growing Waters: Incidence and Media Evaluation.

Levels of Aeromonas hydrophila determined for the shellfish growing area of Grays Harbor, Washington, ranged from 3 to 4600/100 g in oysters and from 3 to 2400/100 ml in water. Of isolates tested, 80% produced a hemolysin, a trait reported to correlate with enterotoxin production and pathogenicity. Two enrichment broths, Tryptic Soy Broth with ampicillin (TSBA) and Modified Rimler Shotts Broth (MRSB) were compared in combination with three solid agar media: Rimler Shotts (RS), Peptone Beef Extract Glycogen (PBG), and MacConkey's (MCA) agars. TSBA was far superior to MRSB in isolating this species from the environmental samples tested.