Introduction
Ever heard of the somewhat popular myth that when you have a wound or cut in your leg, salt water from the beach can help heal it quickly? Well, other than this being a myth, it might not be the best idea, especially if your immune system is compromised. This is because of the possibility of getting infected by an ingenious flesh-eating bacterium that lives in seawater called Vibrio vulnificus.
Flesh-eating bacteria might sound like something out of a horror movie, when in fact they are real, although rare. This bacterium is referred to as flesh-eating primarily because it can trigger multiple wound infections that can advance to necrotizing fasciitis and can become systemic if not controlled. First, let’s dive into some specific information about Vibrio vulnificus.
What is vibrio vulnificus?
Vibrio vulnificus is part of the family of Vibrionaceae which consists of rod-shaped, motile and curved Gram-negative microorganisms. It is a complex opportunistic pathogen that can be lethal and has been studied to be the cause of seafood-related deaths in the United States.1 This bacterium is found in brackish water (i.e. a combination of freshwater and saltwater), estuaries, rivers, deltas, shorelines and deeper ocean surfaces.2 It is halophilic (salt-loving) and appears to require iron for growth and virulence.3
One fascinating fact about this bacterium is that it can shuttle between capsulated and unencapsulated phenotypes.4 However, the capsulated form is responsible for its virulence.4 Also, less than 1% of the isolates from the environment actually belong to the virulence group.5 Hence, this could possibly be the reason for the infrequent occurrence of the infection.5
Though this organism is found throughout the world, most Vibrionaceae are found in warmer marine environments. The summer months have higher incidence rates of the disease. The countries with the most documented cases of V. vulnificus are the United States, South Korea, Taiwan, Japan, and Mexico.2 A study found the prevalence of V. vulnificus in shellfish in coastal seafood markets in Mexico to be 32%.6, 7
How does vibrio vulnificus cause infection?
Infection from V. vulnificus occurs in two ways;
- Intake of contaminated seafood such as oysters, shellfish, etc
- Entry through the skin via an open wound exposed to contaminated seawater or fish bite4
The resulting illnesses from either of the above ways are primary septicemia, gastroenteritis and wound infections.8
Primary septicemia is a bacteremia that usually has no specific route of infection. The portal of entry can either be at the small intestine or the proximal colon.9 It typically begins with an abrupt fever, chills, and gastrointestinal symptoms that may be present or absent. Primary sepsis accounts for approximately 60% of most cases seen.2 The total death rate for this presentation is 50%.2
Gastroenteritis usually presents with watery or bloody stools. This is associated with nausea, vomiting and abdominal cramps lasting for some days and is self-limiting.4 This limited gastrointestinal tract presentation is seen in about 10% to 15% of most V. vulnificus cases studied.2
Wound infections result from rapid colonization of the bacilli, triggering a severe skin reaction, cellulitis and bullae. If uncontrolled, this can progress to necrotizing fasciitis and then overwhelming sepsis.2 The extent of wound infection varies from mild to severe depending on the immune system of the individual. Septicemia occurs with wound infections more in immunocompromised individuals than in immunocompetent hosts.10 Wound infection is seen in approximately 25% of all V. vulnificus cases seen.2
What are the symptoms?
The incubation period after infection varies from 7 to 48 hours according to various studies.12 This is accompanied by the onset of symptoms.12 These symptoms include:
- Vomiting
- Diarrhea
- Fever and chills
- Skin rashes and redness; swelling and pain in infected area13
- Other gastrointestinal symptoms such as stomach pain and cramping14
What are the predisposing factors?
Certain people are shown to have a greater risk of developing complications from V. vulnificus infection. Therefore high-risk patients are those with;
- Liver disease, hemochromatosis, alcoholism, cirrhosis2
- Patients who take gastric acid-lowering medication (antacids)
- Patients with acquired immune deficiency syndrome (AIDS), cancer, diabetes, renal disease and chronic intestinal disease2
- Male gender: This infection is more common in males than females. Also, patients who are above 40 years of age are at increased risk. This age and sex disparity can be linked to the higher occurrence of liver disease in older males15
Treatment options for vibrio vulnificus
If a patient is diagnosed with V. vulnificus infection, it is paramount to commence appropriate antibiotic treatment immediately. Furthermore, in many patients with severe skin and soft tissue infections such as necrotizing fasciitis and skin necrosis, as seen above, surgical interventions such as debridement or fasciotomy are needed in addition to the antibiotic treatment to remove the necrotic tissue and bacteria.16
Most isolates of V. vulnificus are susceptible to different antibiotics in vitro. This includes chloramphenicol, tetracycline, aminoglycosides, third-generation cephalosporins, aztreonam, imipenem and fluoroquinolones.17 In a study with a mouse model, it was found that tetracycline proved to be superior to cefotaxime or gentamicin.17 However, the recently recommended antibiotics treatment regimen is ceftriaxone plus doxycycline or ceftriaxone plus ciprofloxacin.14
Summary
- Vibrio vulnificus infection can be a debilitating condition although most immunocompetent or healthy individuals are not at risk
- The major complications include sepsis, necrotizing fasciitis, skin necrosis and gangrene of the extremities which can even lead to amputation
- Early recognition and appropriate antibiotic therapy is the key to significantly reducing the mortality rate associated with V. vulnificus infection
- A vivid understanding of V. vulnificus infection is crucial for wound care professionals especially those located in areas with a high prevalence of the disease
FAQs
How can infection by V. vulnificus be diagnosed?
Infection caused by V. vulnificus is diagnosed by stool, wounds and blood culture in the laboratory. Once this infection is suspected, the use of selective media that will encourage the growth of the organism is advised for quicker and better diagnosis.
Can this infection be transferred from one person to another?
Vibrio vulnificus infection cannot be transmitted from one person to another. The organism is naturally found in saltwater or brackish water. People with wounds get exposed when the causative organism enters the wound or is consumed via contaminated seafood.
What are some tips for preventing infection caused by V. vulnificus?
Consumption of properly cooked seafood such as oysters, clams and mussels. Also, avoid exposure of wounds to salt or brackish water in a marine environment and wear protective clothing when handling seafood harvested from such waters.
References
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- Haftel A, Sharman T. Vibrio vulnificus Infection. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 [cited 2024 May 8]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK554404/
- Brennt CE, Wright AC, Dutta SK, Morris JG. Growth of Vibrio vulnificus in Serum from Alcoholics: Association with High Transferrin Iron Saturation. Journal of Infectious Diseases [Internet]. 1991 [cited 2024 May 7]; 164(5):1030–2. Available from: https://academic.oup.com/jid/article-lookup/doi/10.1093/infdis/164.5.1030
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- Morris JG, Black RE. Cholera and Other Vibrioses in the United States. N Engl J Med [Internet]. 1985 [cited 2024 May 8]; 312(6):343–50. Available from: http://www.nejm.org/doi/abs/10.1056/NEJM198502073120604.
- Villicaña C, Amarillas L, Soto-Castro L, Gómez-Gil B, Lizárraga-Partida ML, León-Félix J. Occurrence and Abundance of Pathogenic Vibrio Species in Raw Oysters at Retail Seafood Markets in Northwestern Mexico. Journal of Food Protection [Internet]. 2019 [cited 2024 May 8]; 82(12):2094–9. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0362028X22107192.
- Lee SH, Lee HJ, Myung GE, Choi EJ, Kim IA, Jeong YI, et al. Distribution of Pathogenic Vibrio Species in the Coastal Seawater of South Korea (2017–2018). Osong Public Health Res Perspect [Internet]. 2019 [cited 2024 May 8]; 10(6):337–42. Available from: https://ophrp.org/journal/view.php?doi=10.24171/j.phrp.2019.10.6.03
- Daniels NA. Vibrio vulnificus Oysters: Pearls and Perils. Clinical Infectious Diseases [Internet]. 2011 [cited 2024 May 8]; 52(6):788–92. Available from: https://academic.oup.com/cid/article-lookup/doi/10.1093/cid/ciq251
- Chen Y, Satoh T, Tokunaga O. Vibrio vulnificus infection in patients with liver disease: report of five autopsy cases. Virchows Arch [Internet]. 2002 [cited 2024 May 8]; 441(1):88–92. Available from: https://link.springer.com/10.1007/s00428-002-0613-1
- Janda JM, Powers C, Bryant RG, Abbott SL. Current perspectives on the epidemiology and pathogenesis of clinically significant Vibrio spp. Clin Microbiol Rev [Internet]. 1988 [cited 2024 May 9]; 1(3):245–67. Available from: https://journals.asm.org/doi/10.1128/CMR.1.3.245
- Di W, Cui J, Yu H, Cui X, Sa H, Fu Z. Vibrio vulnificus necrotizing fasciitis with sepsis presenting with pain in the lower legs in winter: a case report. BMC Infect Dis [Internet]. 2022 [cited 2024 May 9]; 22(1):670. Available from: https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-022-07655-1
- Blake PA, Merson MH, Weaver RE, Hollis DG, Heublein PC. Disease Caused by a Marine Vibrio: Clinical Characteristics and Epidemiology. N Engl J Med [Internet]. 1979 [cited 2024 May 9]; 300(1):1–5. Available from: http://www.nejm.org/doi/abs/10.1056/NEJM197901043000101
- Walter K. What to Know About Vibrio vulnificus. JAMA [Internet]. 2023 [cited 2024 May 9]; 329(9):772. Available from: https://jamanetwork.com/journals/jama/fullarticle/2801603
- Yun NR, Kim D-M. Vibrio vulnificus infection: a persistent threat to public health. Korean J Intern Med [Internet]. 2018 [cited 2024 May 9]; 33(6):1070–8. Available from: http://kjim.org/journal/view.php?doi=10.3904/kjim.2018.159
- Baker‐Austin C, Oliver JD. Vibrio vulnificus : new insights into a deadly opportunistic pathogen. Environmental Microbiology [Internet]. 2018 [cited 2024 May 9]; 20(2):423–30. Available from: https://sfamjournals.onlinelibrary.wiley.com/doi/10.1111/1462-2920.13955
- Halow KD, Harner RC, Fontenelle LJ. Primary skin infections secondary to Vibrio vulnificus: the role of operative intervention. J Am Coll Surg. 1996; 183(4):329–34.
- Liu J-W, Lee I-K, Tang H-J, Ko W-C, Lee H-C, Liu Y-C, et al. Prognostic Factors and Antibiotics in Vibrio vulnificus Septicemia. Arch Intern Med [Internet]. 2006 [cited 2024 May 9]; 166(19):2117. Available from: http://archinte.jamanetwork.com/article.aspx?doi=10.1001/archinte.166.19.2117