CCMS Medicine Summer 2017 - 21

There is a ~50% death rate from infection in patients who
develop sepsis; this is considered the highest fatality rate for any
bacterium. About 25% will die in a day or two after becoming
ill. Any wound can become infected from a small mosquito
bite, scrape or clearly open cut. In a healthy person, the skin
infection or irritation is minor and may go unnoticed. Being
immunocompromised due to chronic liver disease, chronic
alcoholism, diabetes, chemotherapy, steroid use or medical
conditions like HIV make a person at increased risk of infection.
In these people, the bacteria can get into the bloodstream and
cause serious or life-threatening illness. Vibrio infections progress
very fast and can become evident within 4 hours after exposure.
The capsule of these gram negative rods (bacilli) is thought to
protect against phagocytosis. The more virulent strains of this
bacteria can capture iron bound to transferrin and this is why it
is so dangerous in patients with altered iron metabolism due to
chronic liver disease or hemochromatosis. Increased iron serum
levels enhance the growth of these bacteria and hinder appropriate
actions of neutrophils, thus compounding the virulence of
this organism. These patients can develop a necrotizing skin
infection which leads to a blistering dermatitis. The bacteria then
get into the bloodstream and an invasive septicemia can occur.
This bacteria is 80x more likely to spread into the bloodstream
in immunocompromised people, especially those with chronic
liver disease. In chronic liver disease with cirrhosis, portal
hypertension allows bacteria to directly enter the portal system,
bypassing the hepatic reticuloendothelial system. These patients
then get septic shock which often leads to death. In fact, these
patients are 200 times more likely to die from this infection. This
severe progression of disease may occur regardless of whether
the initial infection was obtained from contaminated food or
an open skin wound. In general, wound infections have a 25%
mortality rate but in patients who develop septicemia there is a
slightly greater than 50% mortality rate. Most of these patients
die in the first 48 hours. Treatment includes IV antibiotic (such
as ceftriaxone, doxycycline and ciprofloxacin). V. vulnificus
produces extracellular toxins which destroy tissue and basement
membranes in blood vessels. Large areas of necrotizing fasciitis
and/or disfiguring ulcers may require surgical debridement or
amputation. Studies suggest males are more likely to have serious
infections as estrogen is thought to have a protective effect.
The second most common Vibrio infection in the US is
Vibrio parahaemolyticus which causes on average 45,000 cases
a year of which 86% are gastrointestinal and 14% are wound
related; there is a 20-30% death rate for wound infections and
only ~2% for gastrointestinal infections. It has a similar disease
pattern to V. vulnificus but appears to be less dramatic. While
this bacteria can be found anywhere, it is commonly found in
Northeast Atlantic coast shellfish.
Why are we seeing an increase in the number of infections
of Vibriosis? Global warming and increased water temperatures
surely play a role. We are seeing an increased threat in areas of
oyster harvest; some scientists believe all oysters are infected with

Vibrio species in the summer months. The warm waters lead to
excessive growth of the organisms. Then there is lack of freshwater
dilution due to, for example, reduced flow of rivers into bays.
Decreased coastal salinity levels (mostly due to climate change)
also allows for greater concentrations of Vibrio within filterfeeding shellfish of the US Atlantic seaboard and Gulf of Mexico,
especially oysters. Oysters are harvested from the Atlantic and
Pacific coasts (~30%) but most (60-70%) are harvested from the
Gulf of Mexico, particularly from Louisiana.
The FDA is considering increasing regulation of the oyster
industry by requiring all oysters be treated prior to consumption
to help eradicate V. vulnificus. However, in our current
government regimen there is defunding of the EPA and denial of
global warming and climate change. There is also anti-regulation
lobbying by the oyster industry and political representation. All of
these things diminish efforts to effectively reduce morbidity and
mortality associated with this disease. As with other important
national and global federal governmental shortsightings,
individual states may have to take the lead on this issue. For
instance, the state of California has had laws (since 1991)
requiring consumer warning labels about the risk of consuming
raw oysters from the Gulf of Mexico. Since 2003 California has
banned the import of raw oysters from the Gulf of Mexico during
the months of April-October unless they were previously treated.
What does this mean for aquarium and fish hobbyists? Can
we get this from our tanks and fish!?! Yes, unfortunately, there is
a theoretical risk. But fortunately this risk should be extremely
low. You should know that V. vulnificus infects fish guts and the
mucous on the skin/scales. Handling raw fish or seafood juices
with open wounds/cuts/broken skin can be a route for infection.
This fact would be important to know especially if you make your
own fish food. Also use of natural saltwater can be a potential
source of introducing infected water to your tank. There are rare
reports of patients getting skin infections after scraping their
hands/arms in their tank(s). Potential sources of infection in your
tank include fish (which can look healthy and still be infected),
shellfish (clams or crabs) or use of natural seawater. I am not
aware of any risk from coral in your tank(s). Coral infected with
Vibrio species (usually not V. vulnificus) in the ocean often show
tissue damage (such as white spots or tissue decay). Although
being immunocompromised increases your risk and potentially
the severity of the illness, it is not a prerequisite. You can still get a
nasty skin infection or rash. In severe cases, open cuts or damaged
skin tissue comes in contact with this bacteria and the bacterial
infection can lead to the breakdown of the tissue (sores and
blisters) or necrotizing fasciitis and subsequently sepsis.
If you develop a skin infection after exposure to your tank or
fish or after exposure to natural seawater/brackish lakes or lagoons
and it progresses rapidly (a red swollen skin lesion, discoloration
of the skin/bruising or blistering that rapidly gets worse and
spreads into surrounding tissue), seek medical attention as soon
as possible. Symptoms include pain, redness, swelling, fever and
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SUMMER 2017 | CHESTER COUNT Y Medicine 21

Table of Contents for the Digital Edition of CCMS Medicine Summer 2017

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