The Brief Case: Safe To Go Back in the Water? Vibrio parahaemolyticus Wound Infection Associated with Brackish Water

Abstract

A previously healthy 12-year-old female presented 1 day after sustaining a laceration of her left lower leg on an unidentified submerged object when she jumped off a dock into a brackish river in Cape Cod, MA. She had initially been evaluated at an urgent care clinic on the day of injury, where the wound was irrigated and sutured. On the following day, she developed worsening pain, erythema, and edema of the leg, as well as fever, and presented to the emergency department, where her vital signs were notable for a temperature of 38.5°C, a heart rate of 112 beats/ min, and a blood pressure of 80/32 mm Hg. Her physical examination was remarkable for an intensely painful 1.5-by-2-cm laceration on the left anterior lower leg, which was productive of serosanguinous drainage and was surrounded by a 6-cm region of erythema. Laboratory results were notable for an elevated white blood cell count of 24.7 ϫ 10 3 /l with 87% neutrophils. She was administered ceftriaxone, doxycycline, and levofloxacin and admitted to the intensive care unit, where she briefly required hemodynamic support with a dopamine infusion.On the second hospital day, the patient underwent incision and drainage of the wound. Aerobic, anaerobic, and mycobacterial tissue cultures were sent. A Gram stain of the original specimen showed no polymorphonuclear cells and no organisms. At 24 h, the aerobic culture plates showed growth of oxidase-positive, straight, Gram-negative rods. The organism grew slowly on MacConkey agar, producing small colonies at 48 h, without production of acid. Two slightly different colony morphologies were both identified as Vibrio parahaemolyticus by the Vitek 2 automated microbial identification system (bioMérieux, Durham, NC) with percent probabilities of 97% (excellent identification) and 95% (very good identification). These were also identified as V. parahaemolyticus by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry with scores of 2.47 and 2.27 (MALDI Biotyper [Bruker Daltonics, Billerica, MA] using the MALDI Biotyper reference library). Susceptibility testing was performed with a microdilution panel (MicroScan Neg MIC 38; Beckman Coulter, Brea, CA) and revealed the organism to be susceptible to all of the antibiotics tested (Table 1).On the basis of the identification and susceptibility testing of the organism, the patient's antibiotic regimen was changed to ceftazidime and doxycycline. She improved clinically and was discharged on hospital day 9 on oral ciprofloxacin and doxycycline to complete a 14-day course of antibiotics. By 2 weeks after hospital discharge, she had fully recovered and the sutures were removed from her wound, which had healed well. DISCUSSIONPathogens commonly recovered from soft tissue infections acquired in a setting of salt or brackish water exposure include Vibrio species (especially Vibrio vulnificus and V. parahaemolyticus), Edwardsiella tarda, Aeromonas hydrophila, Chromobacterium violaceum, Shewanella species, Streptococcus iniae, Erysipelothrix rhusiopath...

Growth Characteristics of Vibrio parahaemolyticus Isolated from Lobster (Panulirus sp.) Under Different Temperatures, pH, and NaCl Concentrations

“…Vibrio is generally oxidase and catalase positive, reduces nitrate to nitrite, is halophilic, requires NaCl for growth, and cannot ferment lactose (Brennan-Krohn et al, 2016). This positive oxidase property is a characteristic of Vibrio that distinguishes it from Enterobacteriaceae (Vila et al, 1992).…”