Water, Water Everywhere – Treatment of water- related infections

Following the recent Hunter weather it’s possible we will see an increase in water- related infections as the clean-up continues. The following comes from the Therapeutic Guidelines: Antibiotic v15

Skin infection or sepsis following contact with water (eg in fishermen, swimmers or aquarium owners) may involve: Aeromonas species (source: fresh or brackish water, or mud); Mycobacterium marinum (most common source: fish tanks); Shewanella putrefaciens; and Vibrio vulnificus, Vibrio alginolyticus and other noncholera vibrios (source: salt or brackish water). Collect samples for Gram stain and cultures before starting antibiotic therapy.

Treatment of water-related infections is difficult—seek expert advice. For mild infection, treat empirically as for mild early cellulitis and erysipelas (with pencillins) and consider adding treatment for specific water-related organisms (see below) depending on the water source. For a contaminated wound infection, use the ciprofloxacin-containing regimen in contaminated or infected wounds. If a pathogen is identified, refer to the individual species below.

For contaminated wounds where there has been significant fresh or salt water exposure use initially

Ciprofloxacin (Adult: 500mg, Child: 12.5mg up to 500mg) orally every 12 hours

PLUS

Clindamycin (Adult: 450mg, Child: 10mg/kg up to 450mg) orally every 8 hours

Modify therapy based on the results of cultures and susceptibility testing.

Aeromonas species

Infections following exposure to fresh or brackish water or mud (eg during water activities, caving, or natural disasters) can involve Aeromonas species. The resulting illness ranges from a superficial skin infection to myositis or sepsis with metastatic complications; the management of these patients requires expert advice. Many patients with Aeromonas infection have a comorbidity (eg malignancy). Use:

Ciprofloxacin (Adult: 400mg IV, 500mg orally, Child: 12.5mg/kg up to adult dose) 12 hourly

Treat uncomplicated infection for 14 days. Longer courses and higher doses may be required for severe infection.

Meropenem or imipenem may be required for polymicrobial infection, or those caused by multidrug-resistant organisms.

Vibrio species

Skin infection following exposure to salt or brackish water may involve Vibrio species. Life-threatening infection can rapidly develop in patients with cirrhosis or iron overload. Local management of skin lesions includes incision, drainage and multiple debridements. There is considerable variability in antimicrobial susceptibility—seek expert advice. For initial treatment, use:

Doxycycline (Adult:200mg, Child 8 years or older: 4mg/kg up to 200mg) for the first dose then doxycycline (Adult:100mg. Child 8 years or older:2mg/kg up to 100mg) 12 hourly

For patients with severe infection add ceftriaxone to doxycycline. Alternative antibiotics may be required, based on antimicrobial susceptibility.

The duration of treatment is determined by clinical response, but can exceed 2 weeks for complicated infections.

Water-related infections can be difficult to manage. See the Therapeutic Guidelines: Antibiotic v15 for more information or seek expert advice.

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