Vibrio vulnificus: Review of Mild to Life-threatening Skin Infections
Vibrio vulnificus is a motile, gram-negative, halophilic, aquatic bacterium that is part of the normal estuarine microbiome and typically is found in warm coastal waters. Infection with the pathogen typically is due to consumption of contaminated seafood or exposure to contaminated seawater. Vibrio vulnificus has a mortality rate of almost 33% in the United States and is responsible for more than 95% of seafood-related deaths in the United States. Vibrio vulnificus can cause a vast spectrum of diseases, such as gastroenteritis, cellulitis, necrotizing fasciitis, and sepsis. Gastroenteritis is self-limited, whereas septicemia often is fatal. Gastroenteritis and septicemia are caused by ingestion of contaminated shellfish, whereas wound infections and necrotizing fasciitis are caused by exposure to contaminated seawater or handling of contaminated seafood. Septicemia is the most common presentation of V vulnificus and accounts for the most fatalities from the bacteria. Prompt diagnosis and treatment are vital to prevent mortality. It is important to keep V vulnificus on the differential when a patient presents with bullae or cellulitis or has a history of raw seafood consumption or exposure to brackish water, as missing the diagnosis could lead to necrotizing fasciitis, sepsis, and death.
Practice Points
- Vibrio vulnificus infection should be high on the differential for patients who present with chronic liver disease and immunosuppression; a history of raw seafood consumption or exposure to brackish water; and bullae, cellulitis, necrotic lesions, or sepsis.
- Time to treatment is directly proportional to mortality rates in V vulnificus infections, and prompt treatment with antibiotics, wound care, debridement, and supportive measures is necessary to decrease mortality rates.
- The incidence of V vulnificus infection is rising in the United States, likely due to a combination of factors, including an aging population with multiple comorbidities, improvements in diagnosis, and climate change.
Interestingly, one reported case of necrotizing fasciitis associated with V vulnificus infection was triggered by acupuncture.16 The patient worked in a fish hatchery, where he was exposed to V vulnificus, and subsequent acupuncture led to the inoculation of bacteria into his bloodstream. This case raises the important point that we typically sequence the pathogenesis of V vulnificus infection as a patient having an open wound that is subsequently exposed to contaminated water; however, it also can follow the reverse sequence. Thus, proper cleansing of the skin after swimming in brackish water or handling shellfish is important to prevent V vulnificus infection.16 Additionally, dermatologists should be sure to cleanse patients’ skin thoroughly before performing procedures that could cause breaks in the skin.
Septicemia
Primary septicemia is the most common presentation of V vulnificus infection.2,8 Septicemia accounts for approximately 58% of V vulnificus infections in the United States.9 Infection typically occurs after ingestion of contaminated oysters, with subsequent absorption into the bloodstream through the ileum or cecum.2,8,9 Patients with chronic liver disease are 80 times more likely to develop primary sepsis than healthy individuals.8 Patients typically present with sudden-onset fever and chills, vomiting, diarrhea, and pain in the abdomen and/or extremities within hours to days of ingestion.4,8,9 The median time from ingestion to symptom onset is 18 hours.4,16 However, symptoms can be delayed up to 14 days.2 Progression is rapid; secondary lesions such as bullae, ecchymoses, cellulitis, purpura, macular or maculopapular eruptions, pustules, vasculitis, urticaria, and erythema multiforme–like lesions appear on the extremities within 24 hours of symptom onset. 2,3,4,8,17 Hemorrhagic bullae are the most common cutaneous manifestation of sepsis.4 Lesions are extremely tender to palpation.3 Cutaneous lesions can progress to necrotic ulcers, necrotizing fasciitis, gangrene, necrotizing vasculitis, or myonecrosis.4,8 Evidence of petechiae may indicate progression to disseminated intravascular coagulation (DIC). Elevated D-dimer and fibrin split products also may indicate DIC, and elevated creatine kinase may signify rhabdomyolysis.3 Unfortunately, septicemia has the worst outcomes of all V vulnificus presentations, with morality rates greater than 50% in the United States.1,2,4Vibrio vulnificus septicemia has a similar case-fatality rate to pathogens such as anthrax, Ebola virus disease, and the bubonic plague.5 Septicemia accounts for approximately 80% of the deaths associated with V vulnificus in the United States.8,9
Septicemia due to V vulnificus progresses to septic shock in two-thirds of cases.8 Septic shock presents with hypotension, mental status changes, and thrombocytopenia.2,8,17 Patients can become tachycardic, tachypneic, and hypoxic. Intubation may be required for resuscitation. In cases of septic shock secondary to V vulnificus infection, mortality rates reach 92%.3 Hypotension with a systolic blood pressure less than 90 mm Hg is a poor prognostic factor; patients presenting with hypotension secondary to V vulnificus infection have a fatality rate approaching 75% within 12 hours.2
Atypical Presentations
Rare atypical presentations of V vulnificus infection that have been reported in the literature include meningitis, corneal ulcers, epiglottitis, tonsillitis, spontaneous bacterial peritonitis, pneumonia, endometritis, septic arthritis, osteomyelitis, rhabdomyolysis endophthalmitis, and keratitis.2,4,6,13,18,19
Diagnosis
When diagnosing V vulnificus, providers need to obtain a thorough patient history, including any history of consumption or handling of raw seafood and recent water activities. Providers practicing in tropical climates or in warm summer months should keep V vulnificus in mind, as it is the ideal climate for the pathogen.9 Vital signs can range from unremarkable to fever, hypotension, tachycardia, and/or hypoxia. Skin examination may show exquisitely tender, erythematous skin with marked soft tissue edema, hemorrhagic bullae, ecchymoses, and/or necrosis. As physical examination findings can be nonspecific, wound cultures, blood cultures, and skin biopsies should be taken.
