Vibrio vulnificus is a species of Gram-negative, motile, curved,
rod-shaped, Pathogenic bacteria of the genus Vibrio. Present in marine
environments such as estuaries, brackish ponds, or coastal areas, V. vulnificus
is related to V. cholerae, the causative agent of cholera., Infection with V.
vulnificus leads to rapidly expanding cellulitis or septicemia. It was first
isolated in 1976. The capsule, made of polysaccharides, is thought to protect
against phagocytosis. The observed association of the infection with liver
disease might be due to the capability of more virulent strains to capture iron
bound to transferrin. Toxin production plays a relevant role in pathogenicity.
Signs and symptoms Vibrio vulnificus is an extremely
virulent bacteria that can cause three types of infections:
(1): acute gastroenteritis from eating raw or undercooked shellfish; V.
vulnificus causes an infection often incurred after eating seafood,
especially raw or undercooked oysters. It does not alter the appearance, taste,
or odor of oysters. Symptoms include vomiting, diarrhea and abdominal pain
(2): necrotizing wound infections of injured skin that is exposed to
contaminated marine water. In other words, the V. vulnificus bacteria can
enter the body through open wounds when swimming or wading in infected waters,
or by puncture wounds from the spines of fish such as tilapia or stingrays. These
patients may develop a blistering dermatitis sometimes mistaken for
pemphigus or pemphigoid. (3): invasive septicemia after eating
raw or undercooked shellfish, especially oysters. V. vulnificus is 80 times more
likely to spread into the bloodstream in people with compromised immune systems,
especially those with chronic liver disease. When this happens, severe
symptoms including blistering skin lesions, septic shock, and sometimes
this can lead to death. This severe infection may occur regardless of
whether the infection began from contaminated food or an open wound.
Among healthy people, ingestion of Vibrio vulnificus can cause vomiting,
diarrhea and abdominal pain. In someone with a compromised immune system,
particularly those with chronic liver disease, Vibrio vulnificus can infect
the bloodstream, causing a severe and life-threatening illness characterized
by fever and chills, decreased blood pressure and blistering skin lesions.
Treatment V. vulnificus wound infections have a
mortality rate around 25%. In patients in whom the infection worsens into
septicemia, typically following ingestion, the mortality rate rises to
50%. The majority of these patients die within the first 48 hours of infection.
The optimal treatment is not known, but, in one retrospective study of 93
patients in Taiwan, use of a third-generation cephalosporin and a
tetracycline were associated with an improved outcome. Prospective clinical
trials are needed to confirm this finding, but in vitro data support the
supposition this combination is synergistic against V. vulnificus.
Likewise, the American Medical Association and the Centers for Disease
Control and Prevention recommend treating the patient with a quinolone or
intravenous doxycycline with ceftazidime. The first successful
documented treatment of fulminant V. vulnificus sepsis was in 1995. Treatment
was Fortaz and intravenous Cipro and IV doxycycline, which proved successful.
Prevention of secondary infections from respiratory failure and acute renal
failure are crucial. Key to the diagnosis and treatment was early
recognition of bullae in an immunocompromised patient with liver
cirrhosis and oyster ingestion within the previous 48 hours, and request by
the physician for STAT Gram stain and blood cultures for V. vulnificus.
V. vulnificus often causes large, disfiguring ulcers that require
extensive debridement or even amputation.
V. vulnificus is commonly found in the Gulf of Mexico, where more than dozen
people have died from the infection since 1990. Most deaths at that time
were occurring due to fulminant sepsis either in the area of oyster harvest and
ingestion or in tourists returning home. Lack of disease recognition and the risk
factors, presentation, and cause were and are major obstacles to good outcome
and recovery. After the successful treatment of the
first patient, the Florida Department of Health was able to trace back the origin
of the outbreak to Apalachicola Bay oysters and their harvesting in water
prone to excessive growth of the organism due to warmth of the water and
lack of fresh water dilution by reduced flow of the Chattahoochee River into the
Apalachicola River into Apalachicola Bay. A similar situation occurred after
Hurricane Katrina in New Orleans. Prognosis
The worst prognosis is in those patients arriving at hospital in a state of
shock. Total mortality in treated patients is around 33%.
Patients especially vulnerable are those with liver disease or immunocompromised
states. With these cases, V. vulnificus usually enters the bloodstream, wherein
it may cause fever and chills, septic shock, and blistering skin lesions.
According to the CDC, about half of those who contract blood infections die.
V. vulnificus infections also disproportionately affect males; 85% of
those developing endotoxic shock from the bacteria are male. Females having
had an oophorectomy experienced increased mortality rates, as estrogen
has been shown experimentally to have a protective effect against V. vulnificus.
History The pathogen was first isolated in 1976
from a series of blood culture samples submitted to the CDC in Atlanta. It was
described as a "lactose-positive vibrio". It was subsequently given the
name Beneckea vulnifica, and finally Vibrio vulnificus by Farmer in 1979.
Increasing seasonal temperatures and decreasing coastal salinity levels seem
to favor a greater concentration of Vibrio within filter-feeding shellfish
of the US Atlantic seaboard and the Gulf of Mexico, especially oysters.
Scientists have frequently demonstrated the presence of Vibrio vulnificus in the
gut of oysters and other shellfish and in the intestines of fish that inhabit
oyster reefs. The vast majority of people who develop sepsis from V.
vulnificus became ill after they ate raw oysters, most of these cases have been
men. Health officials clearly identified
strains of V. vulnificus infections among evacuees from New Orleans due to
the flooding there caused by Hurricane Katrina.
On Thursday, June 18, 2015, an online news story article, featured on the MSN
News webpage, and written by Katy Galimberti, an AccuWeather.com staff
writer, with commentary provided by AccuWeather meteorologist Alex
Sosnowski, stated that eight cases of Vibrio vulnificus infection "have been
reported so far in 2015 across six different counties. Two cases resulted
in death- one in Brevard County, Florida and one in Marion County, Florida." Mr.
Sosnowski then noted that Florida had seen warm months previously, and the
story said that the pathogen prefers brackish warm water around the Gulf
Coastal area. With two deaths out of eight known cases, that localized
outbreak would thus far have a fatality rate of 25%, higher than many other
pathogens but still lower than many others with even higher fatality rates.
Much of the mortality due to Vibrio vulnificus occurs in those patients who
develop generalized infections, and in turn develop sepsis or septic shock;
many, but certainly not all, of those cases are in compromised individuals.
References External links
Large and detailed article on V. vulnificus at Todar's Online Textbook of
Bacteriology CNN video on vibrio vulnificus