Makindo Medical Notes

Introduction

Skin and soft tissue infections (SSTIs) encompass a range of conditions that vary in severity from mild superficial infections to life-threatening necrotizing fasciitis. Prompt recognition and appropriate management are crucial to prevent complications. This guide provides an overview of common SSTIs, their likely causative organisms, and recommended antibiotic regimens based on current clinical guidelines.

General Principles

• Empirical Antibiotic Therapy: Initiate based on the most likely pathogens and local antimicrobial resistance patterns.
• Severity Assessment: Evaluate the extent of infection, systemic symptoms, and patient comorbidities to guide treatment decisions.
• Microbiological Cultures: Obtain samples for culture and sensitivity whenever possible before starting antibiotics.
• Allergy Considerations: Adjust antibiotic choices in patients with known drug allergies, consulting a microbiologist if needed.
• Multidisciplinary Approach: Involve specialists such as infectious disease consultants, microbiologists, surgeons, and diabetic foot teams when appropriate.

Cellulitis

• Common Pathogens: Staphylococcus aureus and Group A streptococci (Streptococcus pyogenes).
• Treatment:
  • Initial Therapy: Benzylpenicillin 1.2 g intravenously (IV) every 6 hours plus flucloxacillin 1 g IV every 6 hours.
  • Oral Switch: Once clinical improvement is observed, switch to oral antibiotics such as amoxicillin 500 mg orally every 8 hours plus flucloxacillin 500 mg orally every 6 hours.
  • Duration: Treat for a minimum of 7 days, adjusting based on clinical response.
• Penicillin Allergy:
  • Use teicoplanin 400 mg IV once daily (following three loading doses of 400 mg IV every 12 hours).
  • For early discharge with ongoing IV therapy, teicoplanin is suitable due to its once-daily dosing.

Diabetic Foot Infections

• Common Pathogens: Polymicrobial, including Staphylococcus aureus, streptococci, and Gram-negative bacilli.
• Mild Infections:
  • Treatment: Co-amoxiclav 625 mg orally every 8 hours.
  • Penicillin Allergy: Clindamycin 300 mg orally every 6 hours.
  • Notes: Ensure close diabetes management and podiatry follow-up.
• Moderate to Severe Infections:
  • Treatment: As per cellulitis management, considering IV antibiotics if systemic signs are present.
  • Severe/Limb-Threatening Infections:
    • This is a medical emergency requiring coordinated care.
    • Treatment: Co-amoxiclav 1.2 g IV every 8 hours.
    • Penicillin Allergy: Consult a microbiologist; clindamycin may be added if osteomyelitis is suspected.
• Multidisciplinary Management: Involve diabetologists, podiatrists, microbiologists, and surgeons as needed.

Leg Ulcers and Pressure Sores

• Colonization vs. Infection: These wounds are often colonized with bacteria, including faecal flora and Pseudomonas aeruginosa, which does not necessitate antibiotic treatment.
• Indications for Antibiotics: Only if there is clinical evidence of infection such as increased pain, erythema, warmth, swelling, or systemic symptoms.
• Treatment: Refer to cellulitis guidelines for appropriate antibiotic therapy.
• Wound Care: Focus on proper wound cleaning and pressure management. Consult a tissue viability specialist nurse.

Postoperative Surgical Wound Infections

• Common Pathogens: Staphylococcus aureus; Group A streptococci are now uncommon.
• Treatment: Flucloxacillin 500 mg to 1 g orally or IV every 6 hours.
• Contaminated Sites (e.g., Groin):
  • Treatment: Co-amoxiclav 625 mg orally every 8 hours or 1.2 g IV every 8 hours.
• Severe Infections: Consult a microbiologist for tailored therapy.
• Penicillin Allergy: Alternative antibiotics should be considered in consultation with a microbiologist.

Necrotizing Fasciitis

• Definition: A rapidly progressing, life-threatening infection causing necrosis of fascia and subcutaneous tissue.
• Common Pathogens: Group A streptococci; may be polymicrobial including anaerobes and Gram-negative organisms.
• Clinical Presentation: Severe pain out of proportion to clinical signs, rapidly spreading erythema, systemic toxicity.
• Management:
  • Urgent Surgical Debridement: Immediate surgical consultation is essential.
  • Empirical Antibiotic Therapy:
    • Benzylpenicillin 1.2 g IV every 4 hours plus clindamycin 600 mg IV every 6 hours plus gentamicin (dosed according to local guidelines).
    • Penicillin Allergy: Clindamycin 600 mg IV every 6 hours plus gentamicin IV.
• Microbiology Consultation: Always involve a microbiologist for guidance on antibiotic choices and dosing.

Fournier's Gangrene

• Definition: A severe necrotizing infection involving the scrotum, perineum, and anterior abdominal wall.
• Common Pathogens: Group A streptococci, other streptococci, coliforms, anaerobes including Clostridium species.
• Management:
  • Urgent Surgical Debridement: Immediate surgical intervention is critical.
  • Empirical Antibiotic Therapy: Piperacillin/tazobactam 4.5 g IV every 8 hours.
  • Penicillin Allergy: Clindamycin 600 mg IV every 6 hours plus gentamicin IV.
• Multidisciplinary Approach: Involve urologists, surgeons, and microbiologists.

Gas Gangrene

• Definition: A life-threatening infection caused by toxin-producing Clostridium species leading to muscle necrosis.
• Common Pathogens: Clostridium perfringens, other Clostridium species.
• Clinical Presentation: Severe pain, swelling, gas in tissues (crepitus), systemic toxicity.
• Management:
  • Urgent Surgical Debridement: Immediate surgical evaluation is necessary.
  • Empirical Antibiotic Therapy: Benzylpenicillin 1.2 g IV every 4 hours plus metronidazole 500 mg IV every 8 hours.
  • Penicillin Allergy: Clindamycin 600 mg IV every 6 hours.
• Hyperbaric Oxygen Therapy: May be considered as an adjunct in specialized centers.

Dirty or Penetrating Wounds

• Risk of Tetanus: Assess tetanus immunization status and provide prophylaxis if indicated.
• Common Pathogens: Staphylococcus aureus, streptococci, anaerobes, and fastidious Gram-negative organisms such as Pasteurella and Eikenella.
• Treatment: Co-amoxiclav 625 mg orally every 8 hours or 1.2 g IV every 8 hours for severe infections.
• Penicillin Allergy: Consult a microbiologist for alternative antibiotic recommendations.

Animal Bites

• High-Risk Patients: Diabetic, asplenic, cirrhotic, and immunosuppressed individuals are at increased risk of severe infection.
• Rabies Consideration: For bites acquired outside the UK, urgently consult a microbiologist regarding the need for rabies prophylaxis.
• Human Bites: Risk of transmission of blood-borne viruses; follow needle-stick injury protocols and consider HIV/hepatitis testing.
• Tetanus Prophylaxis: Assess and administer as needed.
• Treatment:
  • First-Line: Co-amoxiclav 625 mg orally every 8 hours.
  • Penicillin Allergy: Doxycycline 100 mg orally twice daily plus metronidazole 400 mg orally every 8 hours.
  • Duration: Typically 5-7 days; adjust based on clinical response.

Surgical Wound Infections

• Clean Surgery:
  • Common Pathogens: Staphylococcus aureus.
  • Treatment: Flucloxacillin 500 mg to 1 g orally or IV every 6 hours.
• Contaminated Sites:
  • Common Pathogens: Include Gram-negative bacilli and anaerobes.
  • Treatment: Co-amoxiclav 625 mg orally every 8 hours or 1.2 g IV every 8 hours.
• Penicillin Allergy: Consult a microbiologist for appropriate alternatives, such as clindamycin or vancomycin with additional Gram-negative coverage if needed.
• Severe Infections: Involve a microbiologist and consider surgical intervention if there is abscess formation or necrosis.

Key Considerations

• Antibiotic Stewardship: Use antibiotics judiciously to prevent resistance development.
• Adjust Therapy: Modify antibiotic regimens based on culture results and patient response.
• Monitor for Adverse Effects: Watch for signs of antibiotic-associated complications, such as Clostridioides difficile infection.
• Patient Education: Inform patients about the importance of completing the full course of antibiotics and monitoring for side effects.

References

• Clinical Resource Efficiency Support Team (CREST) Guidelines on the Management of Cellulitis in Adults (2005).
• National Institute for Health and Care Excellence (NICE) Clinical Guidelines.
• Infectious Diseases Society of America (IDSA) Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections.
• Local hospital antimicrobial guidelines and formulary.

Introduction

Osteomyelitis and septic arthritis are serious infections of the musculoskeletal system that require prompt diagnosis and management to prevent long-term complications. Osteomyelitis refers to an infection of the bone, while septic arthritis involves infection of a joint space. Both conditions can be acute or chronic and are most commonly caused by bacterial pathogens.

Acute Osteomyelitis

• Likely Causes: The most common causative organism is Staphylococcus aureus. Other pathogens can include streptococci and, less commonly, Gram-negative bacteria.
• Treatment:
  • First-line Therapy: Flucloxacillin 1–2 g intravenously (IV) every 6 hours.
  • Addition of Sodium Fusidate: Sodium fusidate 500 mg orally three times daily may be added if the isolate is sensitive. Monitor liver function tests (LFTs) due to potential hepatotoxicity.
  • Duration of Therapy: Start with 10–14 days of IV antibiotics, followed by an oral switch based on clinical improvement and microbiological advice.
  • Total Treatment Duration: Typically 4–6 weeks for acute osteomyelitis.
  • Penicillin Allergy: Consult a microbiologist for alternative antibiotics, such as clindamycin or vancomycin, depending on sensitivity and patient factors.
• Chronic Osteomyelitis: Management is more complex and often requires prolonged antibiotic therapy and surgical intervention. Consultation with a microbiologist and orthopedic surgeon is recommended.

Septic Arthritis

• Likely Causes:
  • Staphylococcus aureus is the most common cause.
  • Streptococcus species.
  • Neisseria gonorrhoeae, especially in sexually active young adults.
  • Gram-negative rods (e.g., in intravenous drug users or following medical procedures).
• Treatment:
  • Empirical Therapy:
    • Flucloxacillin 1–2 g IV every 6 hours.
    • Add gentamicin IV (dosage per local guidelines) if coliforms (Gram-negative bacteria) are likely.
    • Treat for 2–4 weeks, adjusting based on clinical response and microbiology results.
  • If Neisseria gonorrhoeae Is Suspected:
    • Ceftriaxone 2 g IV once daily for 10–14 days.
    • Consider testing for other sexually transmitted infections.
  • Oral Switch: Transition to oral antibiotics when clinically appropriate, guided by microbiology advice.
  • Penicillin Allergy: Consult a microbiologist for suitable alternatives, such as clindamycin or vancomycin.
• Joint Drainage: Urgent orthopedic consultation for joint aspiration and drainage is essential.

Management Considerations

• Microbiological Investigations:
  • Obtain blood cultures before starting antibiotics.
  • Collect samples from bone (in osteomyelitis) or synovial fluid (in septic arthritis) for Gram stain, culture, and sensitivity testing.
• Imaging Studies:
  • Osteomyelitis: MRI is the preferred imaging modality for early detection.
  • Septic Arthritis: Ultrasound can detect joint effusions.
• Multidisciplinary Approach: Collaboration with microbiologists, infectious disease specialists, and orthopedic surgeons improves patient outcomes.
• Monitoring and Follow-Up:
  • Regularly assess inflammatory markers (CRP, ESR).
  • Monitor for clinical improvement and adverse effects of antibiotics.
  • Adjust treatment based on microbiology results and patient response.

Additional Considerations

• Pediatric Patients: Dosing and management may differ; consult pediatric infectious disease specialists.
• Chronic Osteomyelitis:
  • Often requires prolonged antibiotic therapy (6 weeks or more).
  • Surgical debridement may be necessary.
  • Consult a microbiologist for tailored antibiotic regimens.
• Risk Factors: Diabetes, peripheral vascular disease, immunosuppression, recent surgery, or trauma increase the risk of musculoskeletal infections.

References

• Infectious Diseases Society of America (IDSA) Guidelines for the Diagnosis and Treatment of Native Vertebral Osteomyelitis in Adults.
• British Society for Antimicrobial Chemotherapy (BSAC) Guidelines on Treatment of Bone and Joint Infections.
• National Institute for Health and Care Excellence (NICE) Clinical Knowledge Summaries on Osteomyelitis and Septic Arthritis.

Disclaimer

This information is intended for educational purposes and should not replace clinical judgment. Treatment should be individualized based on patient needs and local antimicrobial resistance patterns. Always consult relevant clinical guidelines and specialists when managing complex infections.

Disclaimer

This guide is intended for educational purposes and should not replace clinical judgment. Always refer to local protocols and consult specialists when managing complex infections or when there is uncertainty regarding treatment choices.