Vibrio vulnificus


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

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