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Wound infections

Introduction.

Wound infections are opportunistic infections of tissue where normal host defenses have obviously been compromised. Thus, the cause of wound infection is diverse, with many strict and opportunistic pathogens involved. Nonetheless, certain microbes are uniquely associated with such infections, rarely causing disease otherwise.

Summary

Cause: Vibrio vulnificus

Microscopy: Gram-negative curved rods
Symptoms: swelling, erythema, pain; later, necrosis and fluid-filled vesicles (bullae)
Transmission: contaminated seawater
Complications: septicemia, shock, death
Pathogenesis: capsule prevents phagocytosis, enzymes cause invasiveness (collagenase, protease, cytolysins)
Treatment: minocycline + ciprofloxacin or cefotaxime

Cause: Pseudomonas aeruginosa

Microscopy: Gram-negative rods
Symptoms: greenish pigmentation in wound
Transmission: direct contact with contaminated soil, water, objects
Complications: MDR - difficult to treat
Pathogenesis: damage to blood vessels; necrosis
Treatment: Multiple antibiotics in combination

Cause: Aeromonas hydrophila

Microscopy: Gram-negative rods
Symptoms: redness, swelling
Transmission: wound contact with contaminated water
Complications: Bacteremia; necrotizing infection
Pathogenesis: Aeromonas possesses virulence factors (proteases, siderophores, hemolysins)
Treatment: Ciprofloxacin

Cause: Acinetobacter baumannii

Microscopy: Gram-negative coccobacilli
Symptoms:
Transmission: Environmental, often introduced during battle trauma (Iraq war)
Complications: septicemia & death
Pathogenesis: Multiple drug resistance
Treatment: cephalosporin or Imipenem + aminoglycoside

Cause: Pasteurella

Microscopy: Gram-negative coccobacilli
Symptoms: Inflammation with cellulitis & lymphadenitis
Transmission: Animal bite or scratch wound
Pathogenesis:
Treatment: Penicillin