Abstract
Shewanella algae
,
S. putrefaciens
, and
Photobacterium damselae
subsp.
damselae
are indigenous marine bacteria and human pathogens causing cellulitis, necrotizing fasciitis, abscesses, septicemia, and death. Infections are rare and are most often associated with the immunocompromised host. A study was performed on the microbiological flora of oysters and seawater from commercial oyster harvesting sites in the Delaware Bay, New Jersey. From 276 water and shellfish samples tested, 1,421 bacterial isolates were picked for biochemical identification and 170 (12.0%) of the isolates were presumptively identified as
S. putrefaciens
, 26 (1.8%) were presumptively identified as
P. damselae
subsp.
damselae
, and 665 (46.8%) could not be identified using the API 20E identification database. Sequencing of the 16S rRNA genes of 22
S. putrefaciens
-like isolates identified them as
S. abalonesis
,
S. algae
,
S. baltica
,
S. hafniensis
,
S. marisflavi
,
S. putrefaciens
,
Listonella anguillarum
, and
P. damselae
. Beta-hemolysis was produced by some
S. algae
and
P. damselae
isolates, while isolates of
S. baltica
and
L. anguillarum
, species perceived as nonpathogenic, also exhibited β-hemolysis and growth at 37°C. To our knowledge, this is the first time these beta-hemolytic strains were reported from shellfish or seawater from the Delaware Bay. Pathogenic
Shewanella
and
Photobacterium
species could pose a health threat through the ingestion of contaminated seafood, by cuts or abrasions acquired in the marine environment, or by swimming and other recreational activities.