Results

Population and Temporality of Infections

Data from 67 patients diagnosed with Vibrio infection were available for the period 2001–2019 (Table 1). Most patients were men (81%), and the average age was 54 years (SD +24 years). In the subgroup of patients with acute infections (including cutaneous infections and gastroenteritis), the mean age was 60 (SD +20) years, and 71% of the patients had >1 underlying condition. Patients with chronic ear infections were younger (mean age 27 years [SD +24 years]), and all but 1 had no underlying conditions.

The description of environmental factors was available for 57% of patients. Among those patients, 55.3% of infections were contracted at the beach, 39.5% by handling or eating seafood, and 5.3% while abroad. Most infections (82%) occurred during June–September. The number of reported cases reached 2 peaks, in 2003 and 2018.

Clinical Features

The average duration between known exposure and onset of symptoms was 2.4 days (SD +3.8 days), and it varied from <1 day for patients with gastroenteritis, cellulitis, or pneumonia, to 20 days for patients with osteitis. Digestive disorders were reported in 23 (34.4%) of the patients, including 6% with severe intraabdominal infection (Table 2). Cellulitis was reported in 23 (34.4%) of the patients, and 3 had soft tissue infection complicated by osteitis. Near drowning–associated pneumonia was reported in 8 (12%) of the patients. A case of endocarditis was described in a patient whose pacemaker had been exposed to seawater through a preexisting chronic wound while swimming in the Atlantic Ocean. Chronic ear infection (chronic otitis or cholesteatoma) affected 12 (18%) of the patients.

Diagnostic Testing, Vibrio Species, and Drug-Susceptibility Testing

Vibrio infections were diagnosed from blood samples (26.9%), feces (20.9%), biopsies (20.9%), ear swab samples (17.9%), bronchoalveolar lavage samples (7.5%), and skin samples (6%). The most frequently identified species were V. alginolyticus (34%) and V. parahaemolyticus (30%). V. cholerae non-O1/O139 was found in 15% of patients, and V. vulnificus was found in 10%. The remaining patients were infected with other Vibrio species. Other bacteria were co-isolated in samples from 5 patients (methicillin-sensitive Staphylococcus aureus in 2 skin samples; Streptococcus mitis in a bronchoalveolar lavage; Proteus vulgaris and Haemophilus influenza in another bronchoalveolar lavage; and Klebsiella pneumoniae, Enterococcus faecalis, and Enterobacter cloacae in a bone biopsy).

Susceptibility testing revealed strains with resistance or intermediate resistance to amoxicillin in most V. alginolyticus, V. parahaemolyticus, and V. cholerae non-O1/O139 strains (Table 2). Strains with resistance or intermediate resistance to ticarcillin were also found in most V. alginolyticus and V. parahaemolyticus strains and to a lesser extent in V. cholerae non–O1/O139 strains. V. vulnificus strains were sensitive to all of these penicillins.

Diseases Caused by Vibrio infection

V. alginolyticus was responsible for various pathologies, but more particularly for otitis (39%) (Figure).

Enlarge

Figure. Diseases caused by Vibrio infection in 67 patients, by species, Bay of Biscay, France, 2001–2019. A) V. alginolyticus. B) V. parahaemolyticus. C) V. cholerae non-O1/O139. D) V. vulnificus. Numbers in chart sections indicate number of patients. Intraabdominal infection corresponds to pancreatitis, liver abscess, phlegmoneous ileitis, cholecystis, and peritonitis.

V. parahaemolyticus was identified in patients with cellulitis (40%) and gastroenteritis (40%). V. cholerae non-O1/O139 was almost exclusively responsible for digestive disorders (90%). V. vulnificus was exclusively found in cellulitis and soft tissue infections complicated by osteitis.

Treatment

Most (84%) patients required hospitalization. The average time from symptom onset to treatment was 2.7 days (SD +4.9) days. Most of the patients received antibiotics (90%), of whom >50% received a multidrug regimen. The main prescribed antibiotics were penicillins (91%), quinolones (36%), cephalosporins (30%), metronidazole (15%), tetracycline (10%), and aminoglycosides (9%).

Twenty-two patients (33%) underwent surgery. Eleven patients with necrotizing cellulitis and 3 patients with osteitis required surgical debridement. For 6 of those 11 patients, amputation was necessary. Five patients with chronic ear infection required either surgical excision (n = 3), meatotomy (n = 1), or tympanoplasty (n = 1). Two patients had a cholecystectomy, and 1 patient with phlegmonous ileitis had partial colectomy.

Factors Associated with Severe Forms

All patients with chronic infection were cured. Among patients with acute infection, 13 (24%) went into septic shock (Table 3), 6 (11%) had amputations, and 8 (14%) died. Half of the amputations were associated with V. vulnificus infections. Older age and malignant hemopathy (e.g., acute leukemia and lymphoma under chemotherapy) were associated with death. Three patients suffered pneumonia after near drowning, and death may have been attributable to cardiorespiratory arrest and intensive care complications. A probable link between Vibrio infection and death could be established for 5 patients. The case-fatality rate was the highest for V. vulnificus infections (1 attributable death out of 7 infections), followed by V. parahaemolyticus (2 attributable deaths out of 19 infections) and V. cholerae non-O1/O139 (1 attributable death out of 10 infections). The case-fatality rate was the lowest for V. alginolyticus infections (1 attributable death out of 14 infections).