Clinical Overview of Vibriosis

Etiology

Vibrio are gram-negative bacteria that are naturally found in warm, salty marine environments, such as salt water and brackish water.

More than 20 Vibrio species can cause the human illness vibriosis.

The most common species causing vibriosis in the United States are

• Vibrio parahaemolyticus
• Vibrio vulnificus
• Vibrio alginolyticus

Risk of death

Some Vibrio species, such as Vibrio vulnificus, can cause particularly severe and life-threatening infections.

Many people with Vibrio vulnificus infection require intensive care or limb amputations, and about 1 in 5 people with this infection die, sometimes within a day or two of becoming ill.

Signs and symptoms

People with vibriosis typically have watery diarrhea. They also can have abdominal cramping, nausea, vomiting, and fever.

Some people with vibriosis have a wound or soft tissue infection.

In people with underlying medical conditions, especially liver disease, Vibrio bacteria can cause bloodstream infections characterized by fever, chills, dangerously low blood pressure, blistering skin lesions, and sometimes death.

Diagnosis and testing

When to suspect vibriosis

• Consider Vibrio as a possible cause of infection in patients with watery diarrhea who have recently eaten raw or undercooked seafood, especially oysters.
• Consider Vibrio as a possible cause of infection in wounds that were exposed to coastal waters, especially in patients with increased risk for Vibrio infection.
  • If you suspect Vibrio wound infection, immediately begin treatment. Do not wait for consultation or laboratory confirmation.

Diagnosis

Infection is diagnosed when Vibrio are identified in the stool, wound, or blood of a patient with symptoms of vibriosis.

Testing

Vibrio can be detected by culture-independent diagnostic testing or by isolating the bacteria from a clinical specimen by culture.

• If a culture-independent diagnostic test (CIDT) is positive, CDC recommends ordering culture confirmation, when possible. CIDTs do not differentiate between non-cholera Vibrio, which is necessary to make treatment decisions.
• If a culture is performed, CDC recommends the use of selective media, such as thiosulfate citrate bile-salts (TCBS) agar, for examining stool specimens.

Considerations for Vibrio wound infection

• Obtain wound or hemorrhagic bullae cultures and send all V. vulnificus isolates to a public health laboratory.
  • Blood cultures are also recommended if the patient is febrile, has hemorrhagic bullae, or has signs of sepsis.
• Ask the patient or family about relevant exposures. Did the patient:
  • Have an open wound (including from a recent surgery, piercing, or tattoo) that might have come in contact with coastal water, including salt water or brackish water? Brackish water is a mixture of salt water and fresh water, such as where the river meets the ocean.
  • Get a scratch or a cut while in or around coastal water?
  • Have an open wound that might have come in contact with raw or undercooked seafood or juice or drippings from raw or undercooked seafood?

Use answers to guide treatment decisions.

Treating intestinal illness

Treatment is not necessary in mild cases, but patients should drink plenty of liquids to replace fluids lost through diarrhea.

Antibiotics can be lifesaving for patients with severe illnesses.

Treating wound infection

Initiate treatment promptly. Do not wait for consultation with an infectious disease specialist or for laboratory confirmation of Vibrio vulnificus infection.

Start antibiotic therapy.

• A third-generation cephalosporin (e.g., ceftazidime 1–2g IV/IM every 8 hours) plus doxycycline (100mg PO/IV twice a day for 7–14 days) is recommended.1
  • Alternate regimens include a third-generation cephalosporin with a fluoroquinolone (e.g., 500mg ciprofloxacin PO twice a day) or a fluoroquinolone given alone.23
• Children may also be treated with a third-generation cephalosporin plus doxycycline or a fluoroquinolone.
  • However, doxycycline and fluoroquinolones are sometimes avoided in children due to concerns about side effects.
• Children may be treated with an alternative regimen of trimethoprim-sulfamethoxazole plus an aminoglycoside.4
• Doses should be appropriately adjusted for renal and hepatic function.
• If appropriate, consult a microbiologist or infectious disease specialist.

Give careful attention to the wound site.

• Necrotic tissue should be debrided.
• Severe cases might require
  • Aggressive debridement
  • Fasciotomy
  • Amputation of the infected limb