Antimicrobial Guidelines

Bone and Joint

Acute Osteomyelitis and Septic Arthritis

• Take diagnostic samples before starting antimicrobials unless the patient has severe sepsis or acute neurological deficits.
• Follow empiric guidelines for non-vertebral osteomyelitis, and consult Infections Diseases (ID) for vertebral disease.
• Consult ID for treatment duration and follow-on oral agents, if appropriate (oral agents no longer specified).
• For patients on flucloxacillin or cefazolin, add vancomycin for cover against methicillin-resistant S. aureus (MRSA) if risk factors exist:
  • known recent MRSA-positive,
  • household contact with known recent MRSA-positive,
  • recent admission to any overseas healthcare facility,
  • residence overseas.

Cardiovascular System

Bacterial Endocarditis Treatment

• Native valve: benzylpenicillin empiric dose increased to IV 2.4 g 4-hourly to cover more resistant streptococci.
• Prosthetic valves, implantable cardiac devices, hospital-acquired: empiric regimen now includes flucloxacillin with vancomycin and gentamicin for better activity against staphylococci.
• All regimens involve high-doses of renally-cleared agents. Consider dose reduction in renal impairment.
• Consult with ID for treatment duration (2–6 weeks depending on organism and type of valve in situ), and tailoring of treatment against susceptibilities.

Central Nervous System

Meningitis - Adults

• Treatment duration is now specified for various pathogens.
• Clinical risk factors for resistant S. pneumoniae (requiring addition of vancomycin to empiric treatment), e.g. known or suspected otitis media or sinusitis, are now emphasised.
• For severe penicillin allergy, moxifloxacin IV is now first-line. Ciprofloxacin plus vancomycin [± trimethoprim+sulfamethoxazole for listeria] (all IV) is second-line and may be given if delays are anticipated with moxifloxacin access.
• Ceftriaxone dose for N. meningitidis in patients with mild penicillin allergy has been increased to IV 2 g 12-hourly.

Ear, Nose, and Throat

Acute Epiglottitis and Deep Neck Space Infections

• For acute epiglottis, anaerobic cover is not needed unless other structures involved (refer deep neck space guideline).
• Only IV treatment options given (oral follow-ons removed).
• Empiric treatment in severe penicillin allergy has changed to ciprofloxacin IV plus vancomycin IV (was clindamycin IV) for acute epiglottis, with metronidazole IV added for deep neck space infections.

Tonsillopharyngitis (was 'pharyngitis')

• Cefalexin added as an option for mild penicillin allergy.

Chronic Rhinosinusitis (was 'chronic sinusitis')

• Content updated to reflect inflammatory aetiology.

MRSA

Decolonisation protocol

• Octenidine 0.3% wash has replaced triclosan as an alternative to chlorhexidine 4% solution in cases of intolerance or sensitive skin.

Surgical prophylaxis

• Add vancomycin to standard antimicrobials for surgical prophylaxis if patient is MRSA colonised, or has prior MRSA colonisation and their current status is unknown.

MRSA Bacteraemia

• Duration of treatment should be at least 2 weeks of IV antimicrobials, and ID should be consulted in all cases.

Skin and Soft Tissue

Infected Bite Wounds (Animal and Human) (was 'Bites – human and animal')

• For mild infections in patients with mild penicillin allergy, use oral metronidazole (was clindamycin) and either trimethoprim+sulfamethoxazole or doxycycline.

Cellulitis - Simple and Erysipelas

• Advice to consider referral for home IV antimicrobials now removed as oral dosing strategies can often be deployed.

Infected Ulcers (e.g. diabetic, vascular, pressure) (was 'Cellulitis – complicated/ulcers')

• Initial text altered to indicate that antimicrobials should only be used if clear signs of infection.
• For mild or moderate infections in patients with severe penicillin allergy, treatment is now with ciprofloxacin PO (was gentamicin IV) and clindamycin PO.
• For severe infections, empiric treatment is with piperacillin+tazobactam, meropenem in mild penicillin allergy, and ID consultation for severe allergy.

Necrotising Soft Tissue Infections

• Empiric treatment now divided into limb (flucloxacillin and clindamycin) and abdominal/peritoneal (piperacillin+tazobactam and clindamycin) infections.
• Clindamycin dose is reduced to IV 600 mg 8-hourly, and flucloxacillin IV increased to IV 2 g 4-hourly.

Varicella Zoster

Now divided into uncomplicated and complicated disease, with definitions for complicated disease (e.g. severely immunocompromised, ophthalmic involvement) given.

Universal changes (throughout guidelines)

• Clindamycin IV and PO dosing is now three times daily.
• Clindamycin is > 90% orally available so IV dosing is not routinely recommended for milder infections e.g. cellulitis.
• PHARMAC restrictions are now accessed via the buttons under drug listing ( not as separate bullet points).
• Costings no longer listed for recommended dosing regimen.