What is the treatment for a wound infected with Serratia marcescens and Pseudomonas?

Treatment for Wound Infected with Serratia marcescens and Pseudomonas

For a wound infected with Serratia marcescens and Pseudomonas, treatment should include surgical debridement combined with broad-spectrum antibiotics effective against both pathogens, such as imipenem or a combination of an antipseudomonal beta-lactam plus a fluoroquinolone. 1, 2

Initial Management Approach

• Surgical intervention is essential and should include thorough debridement of necrotic tissue to remove the focus of infection 1
• Wound cultures should be obtained before starting antibiotics to guide definitive therapy 1
• Empiric antibiotic therapy should be started immediately after obtaining cultures 1

Antibiotic Selection

First-line Options:

• Imipenem/cilastatin: Effective against both Serratia marcescens and Pseudomonas aeruginosa 2
• Piperacillin-tazobactam: Provides broad coverage for both pathogens 1
• Cefepime: Effective against both organisms and has good tissue penetration 3, 4

Alternative Regimens:

• Combination therapy: An antipseudomonal beta-lactam (cefepime, meropenem) plus levofloxacin or ciprofloxacin 1, 5
• For patients with penicillin allergy: Aztreonam plus an aminoglycoside 1

Special Considerations

• Polymicrobial wound infections are common, especially in burn wounds, pressure ulcers, and traumatic wounds 1
• Both Serratia marcescens and Pseudomonas can rapidly develop resistance during treatment, necessitating periodic culture and susceptibility testing 5, 6
• Serratia marcescens can cause devastating infections if not properly treated, with high mortality rates in invasive infections 3, 7

Duration of Therapy

• For uncomplicated soft tissue infections: 7-14 days of antibiotics 1
• For complicated infections with deeper tissue involvement: 2-3 weeks 1
• Continue antibiotics until resolution of infection signs, but not necessarily through complete wound healing 1

Wound Care

• Regular wound cleaning with sterile normal saline 1
• Avoid iodine or antibiotic-containing solutions for routine cleaning 1
• Keep draining wounds covered with clean, dry bandages 1
• Elevation of the affected body part if swelling is present 1

Monitoring and Follow-up

• Monitor for signs of spreading infection (increasing erythema, warmth, pain) 1
• Repeat cultures if clinical response is inadequate after 48-72 hours of therapy 1
• Watch for development of resistance, particularly with Pseudomonas infections 5, 6

Pitfalls to Avoid

• Delaying surgical debridement can lead to treatment failure, even with appropriate antibiotics 1, 8
• Underestimating the severity of infection can result in inadequate antibiotic coverage 1, 3
• Failing to adjust antibiotics based on culture results can lead to treatment failure due to resistance 1, 6
• Not considering local resistance patterns when selecting empiric therapy 1

Remember that both Serratia marcescens and Pseudomonas aeruginosa can be highly resistant pathogens, and treatment success depends on aggressive surgical management combined with appropriate antimicrobial therapy guided by susceptibility testing 8, 4.