V. vulnificus is an opportunistic human pathogen transmitted from seawater, raw oyster, and shellfish. The spectrum of disease can vary from gastroenteritis to severe septicemia and necrotizing fasciitis.
Patients with certain underlying medical conditions are susceptible to V. vulnificus infections. Patients with alcoholic liver disease, diabetes mellitus, gastrointestinal and hematologic disorder, malignancy, and iron overload states have a higher risk of infection [9]. Moreover, kidney diseases, including ESRD, are regarded as other potential contributing risk factors for V. vulnificus infection. Functional abnormalities of neutrophils, monocytes, dendritic cells, and lymphocytes have been observed in uremia, which makes patients prone to specific life-threatening infections [10]. In addition, dialysis patients have frequently elevated iron levels because of blood transfusion or iron supplement for significant anemia. Iron is believed to facilitate V. vulnificus infection by enhancing the growth of the organism and possibly reducing the activity of neutrophils [11]. V. vulnificus grows rapidly when transferrin saturation exceeds 70 % [12]. In this context, a relatively high transferrin saturation in our patient might be an additional risk factor for infection.
V. vulnificus infection has not been well described in patients undergoing peritoneal dialysis. Interestingly, there are only 2 case reports of V. vulnificus peritonitis after consuming or handling seafood in patients undergoing CAPD, and these patients completely recovered after oral and intraperitoneal antibiotic treatments [7, 8]. Similarly, our patient showed peritonitis after ingesting raw seafood. The proportion of V. vulnificus infections in Korea and the United States has rapidly increased during the last decade due to the increased consumption of raw fish or shellfish [1, 3]. Although previous reports of V. vulnificus peritonitis, including our report, were conducted in Asia, patients undergoing CAPD and live in an area with high incidence of V. vulnificus infection should avoid raw or undercooked seafood to prevent infection. A remarkable finding about our case was that peritonitis was followed by severe septicemia and necrotizing fasciitis. We could presume that V. vulnificus in the peritoneal fluid might penetrate the peritoneum or bowel wall into the blood stream, which results in septicemia. Therefore, peritonitis might be an important clinical manifestation of V. vulnificus infection in peritoneal dialysis patients. Furthermore, according to our findings, patients undergoing peritoneal dialysis are highly susceptible to various degrees of V. vulnificus infection from peritonitis to septicemia and necrotizing fasciitis.
An array of phenotypic and genomic techniques has become available for the identification of Vibrio species. However, Vibrio and other closely related species show similar phenotypic features and are not easily distinguished biochemically [13]. The identification of Vibrios isolated from the aquaculture environment has been imprecise and requires many biochemical and/or physiological tests. Although the 16S rRNA gene sequencing method may be less reliable because many different species within the genus Vibrio may contain identical 16S rRNA gene sequences, it remains one of the most commonly used methods for bacterial identification [14]. 16S rRNA gene sequencing can be used in hospitals to identify V. vulnificus that are difficult to identify using phenotypic and biochemical methods.
Moreover, the recommended antibiotic therapy for V. vulnificus is tetracycline family (e.g. tetracycline, doxycycline, and minocycline) plus third-generation cephalosporin [15]. Alternative antibiotics therapies are cefotaxime or ciprofloxacin [1]. In a recent retrospective study, fluoroquinolones were found to be the best option for the antibiotic treatment of necrotizing fasciitis caused by V. vulnificus [16]. Therefore, fluoroquinolones or tetracycline plus third-generation cephalosporin could be prescribed empirically in a patient with severe V. vulnificus infection.
Despite reports of high mortality from V. vulnificus infection, our patient recovered without complication. Necrotizing fasciitis is a life threatening soft tissue infection with a high mortality rate, which requires emergent surgical fasciotomy, debridement, and broad-spectrum antibiotic treatment when the diagnosis is confirmed [17]. Consequently, early surgical intervention was performed and adequate antibiotics treatments were administered to our patient; these strategies might dramatically improve the patient’s survival. Finally, suspicion of V. vulnificus infection in vulnerable patients who ingest raw seafood is essential for prompt diagnosis, which could significantly improve patient outcomes.
Consent
Written informed consent for publication of this case and any accompanying images was obtained from the patient. A copy of the written consent is available for review by the Editor of this journal.