See [[Marine Envenomation]] > [!key points] > - ADT > - clean wound Skin infection or sepsis following immersion of a wound in water (eg in fishermen, swimmers or aquarium owners, or with a marine animal bite — including shark or crocodile bites — or coral cut) may involve: - _Aeromonas_ species (source: fresh or brackish water, and mud; exposure risks: caving, natural disasters and medicinal leech therapy) - _Mycobacterium marinum_ (most common source: fish tanks) - _Shewanella putrefaciens_ - _Vibrio vulnificus_, _Vibrio alginolyticus_ and other noncholera vibrios (source: salt or brackish water) - _Staphylococcus aureus_, including methicillin-resistant strains - _Streptococcus pyogenes_ (group A streptococcus) (source: coral cuts). # treatment Careful cleaning, and debridement if necessary, of wounds that have been immersed in water is important to prevent infection. For patients with traumatic water-immersed wounds, ensure that tetanus immunisation is up-to-date. ==Preventative antibiotics are not routinely required for wounds that have been immersed in water.== Prophylaxis is required for traumatic water-immersed wounds that require surgical management or are significantly contaminated. Presumptive therapy is required for marine animal bite wounds at high risk of infection (see Principles of management of bites and clenched fist injuries for risk factors). Consider early empirical therapy for patients with risk factors for developing severe infections (eg liver disease, iron overload, immune compromise due to immunosuppressive medications, diabetes or malignancy). Water-immersed wound infections can progress rapidly and even localised infections require close monitoring. Combined medical and surgical management is often required. Seek expert advice if infection is associated with systemic symptoms or involves deeper tissues (such as bones, joints or tendons), or if localised infection progresses. The appropriate antibiotic regimen for definitive therapy depends on the pathogen. Collect samples of infected tissue or wound exudate for Gram stain, culture and susceptibility testing before antibiotic therapy is started. Modify therapy based on the results of culture and susceptibility testing. ## seawater wound local infection - doxycycline 100mg q12h (child >8 y and <26kg/ 50mg; 26-35kg: 75mg) Plus - fluclox 500mg (12.5mg/kg up to 500) QID OR cefalexin 500 mg (child: 12.5 mg/kg up to 500 mg) orally QID Child < 8: cipro 12.5mg/kg up to 500 BD If MRSA risk: trimethoprim+sulfamethoxazole 320+1600 mg (child 1 month or over: 8+40 mg/kg up to 320+1600 mg) orally, 12-hourly **If systemic illness** Fluclox IV 2g QID (50mg/kg) (cefazolin if penicillin allergy) Plus Cipro 400mg IV TDS (10mg/kg) +/- vanc if MRSA concern or clinda ## Fresh, brackish, aquarium or soil- or sewage-contaminated water–immersed wounds - trimethoprim+sulfamethoxazole 320+1600 mg (child 1 month or over: 8+40 mg/kg up to 320+1600 mg) orally, 12-hourly OR cipro + fluclox (same doses as above) If sewage: flagyl 400 mg (child: 10 mg/kg up to 400 mg) orally, **Systemically unwell** cefepime 2 g (child: 50 mg/kg up to 2 g) intravenously, 8-hourly Plus Flagyl 500mg BD (12.5mg/kg) IV