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.
Wound Care
Wound infections must be extensively irrigated.9,21 For mild wound infections, proper wound care and oral antibiotics are appropriate (Table).21 Mild wounds should be irrigated thoroughly and followed by wound coverage to prevent progression, secondary infection, and necrosis. The dressing of choice will depend on the presenting lesion and provider preference; nonadherent, occlusive, or wet-to-dry dressings often are the best choices.22 Nonadherent dressings, such as petrolatum-covered gauze, do not pull off the newly formed epithelium when removed, making them beneficial to the skin’s healing process. Another option is occlusive dressings, which maintain a moist environment to hasten healing. They also enhance the autodigestion of necrotic tissue, which can be beneficial for necrotizing V vulnificus infections. Wet-to-dry dressings also may be used; these typically are comprised of gauze soaked with water, an astringent, and an antimicrobial or antiseptic solution. These dressings help to treat acute inflammation and also remove any exudate from the wound.22
Soft tissue and necrotizing infections require debridement.2,8 Early debridement decreases mortality rates.2,8,9 Necrotizing fasciitis often requires serial debridement to clear all the dead tissue and reduce the bacterial burden.8,9 Debridement prevents contiguous spread and metastatic seeding of the bacteria; it is important to prevent spread to the blood vessels, as vasculitis can necrose vessels, preventing antibiotics from reaching the dead tissue.17 Providers also should monitor for compartment syndrome, which should be treated with fasciotomy to decrease mortality.9,23 Many physicians leave V vulnificus–infected wounds open in order to heal by secondary intention.9 Hyperbaric oxygen therapy may be helpful as an adjunct to aggressive antimicrobial treatment for wound healing.8
,Supportive Measures
Supportive care for dehydration, sepsis, DIC, and septic shock may be necessary, depending on the patient’s course. Treatment for severe V vulnificus infection includes intravenous fluids, crystalloids, oxygen, and/or intubation. Furthermore, if DIC develops, fresh frozen plasma, cryoprecipitate, a packed red blood cell transfusion, and/or anticoagulation may be required for resuscitation.3
Timing
Time to treatment and fatality rate are directly proportional in V vulnificus infection; the greater the delay in treatment, the higher the fatality rate.2 A 24-hour delay in antibiotic treatment is associated with a 33% case-fatality rate, and a 72-hour delay is associated with a 100% case-fatality rate.9 Even with early, appropriate treatment, mortality rates remain high.4
Prevention
Prevention of V vulnificus infections is an important consideration, especially for patients with chronic liver disease, immunosuppression, and hemochromatosis. Public education about the risks of eating raw shellfish is important.4 Oysters need to be treated properly to prevent growth and survival of V vulnificus.2 The most reliable method for destroying the bacteria is cooking shellfish.8,13 Only 15% of high-risk patients in the United States are aware of the risks associated with raw oyster consumption.3 High-risk patients should avoid eating raw oysters and shellfish and should cook seafood thoroughly before consumption.2,8 They also should wear protective clothing (ie, gloves) and eye protection when handling seafood and protective footwear (ie, wading shoes) while in seawater.2,8,13 It also is important to avoid contact with brackish water if one has any open wounds and to cleanse properly after exposure to brackish water or shellfish.2,8,16 Because severe V vulnificus infections can lead to death, prevention should be strongly encouraged by providers.2
Conclusion
Vibrio vulnificus infection typically occurs due to consumption of contaminated seafood or exposure to contaminated seawater. It most frequently affects older male patients with chronic liver disease, immunosuppression, hemochromatosis, or diabetes mellitus. Vibrio vulnificus can cause a vast spectrum of diseases, including gastroenteritis, wound infections, necrotizing fasciitis, and sepsis. Septicemia is the most common presentation of V vulnificus infection and accounts for the most fatalities from the bacteria. Septicemia often presents with fever, chills, vomiting, diarrhea, and hemorrhagic bullae. Vibrio vulnificus also commonly causes necrotizing fasciitis, which initially presents as cellulitis and rapidly progresses to hemorrhagic bullae or necrosis with accompanying systemic symptoms. Prompt diagnosis and treatment are vital to prevent mortality.
Interestingly, regions impacted by V vulnificus are expanding because of global warming.5,7Vibrio vulnificus thrives in warm waters, and increasing water temperatures are enhancing V vulnificus growth and survival.1,9 As global warming continues, the incidence of V vulnificus infections may rise. In fact, the number of infections increased by 78% between 1996 and 2006 in the United States.5 This rise likely was due to a combination of factors, including an aging population with more comorbidities, improvements in diagnosis, and climate change. Thus, as the number of V vulnificus infections rises, so too must providers’ suspicion for the pathogen.