The isolate was identified as S algae by VITEK 2 and susceptible to piperacillin-tazobactam,
ceftazidime, cefotaxime, Fluorouracil ic50 imipenem, ciprofloxacin, and aminoglycosides. In the light of an S algae infection, the patient was further interviewed about seawater exposure. The patient reported that she had bathed frequently in the Mediterranean Sea near Orebiz during her stay in Croatia. Treatment with mycophenolate-mofetil was stopped and the dose of prednisolone was reduced to 20 mg/day. The patient received piperacillin 0.5 g tid and ciprofloxacin 500 mg bid for 20 days, and on X-ray films an intact corticalis and no signs of osteolysis could be detected on both lower limbs. Magnetic resonance imaging could not be performed because of residual metallic structures left in situ after a former bone fracture. During antibiotic therapy the ulcers healed continuously and the immunosuppressive treatment was further reduced to 15 mg prednisolone. Chronic Bleomycin in vivo cutaneous ulcers of the legs have been identified as the most common risk factor for S algae skin infections. Bacteremia is rare and has been described in patients with leg ulcers and immunosuppression or other underlying medical conditions. Severe cases of osteomyelitis after trauma and contact to stagnant water, and myonecrosis and necrotizing fasciitis leading
to amputation after seawater exposure have been reported. In skin infections, hemorrhagic bullae are characteristic, as seen here.[1, 4, 5] Cutaneous infections with Vibrio vulnificus and Aeromonas hydrophila, other seawater-associated bacterial pathogens, closely resemble the clinical picture. In temperate regions, S algae can be found during the summer months in seawater as well. The organism had often been misidentified as Shewanella putrefaciens based on biochemical characteristics and lack of microbial database entries in the past.[2, 3] It was shown retrospectively that most infections were in fact caused by S algae[2, 3, 7] and 16srRNA gene polymerase chain reaction amplification followed by sequencing for correct identification was performed by several
investigators.[3, 4, 6, 8] O-methylated flavonoid Shewanella algae is considered to be more pathogenic than S putrefaciens. Infections should be treated aggressively with a combination of surgery or drainage and antibiotic therapy[1, 2]; however, there is little clinical experience. Shewanella algae is resistant against penicillins and first- and second-generation cephalosporins,[1, 2, 6, 9] and development of resistance to piperacillin-tazobactam and imipenem under therapy has been described. However, naturally occurring derepressed Ambler class D beta-lactamases have been accused for that effect. Most often, S algae is susceptible to ceftazidime, cefotaxime, aminoglycosides (especially amikacin), and quinolones,[1, 2, 6, 9] although S algae has been described to harbor quinolone resistance progenitor genes.