Empirical coverage:

Cloxacillin 2g IV q6h

To tailor antibiotics according to definitive cultures.

Antibiotic allergy: 

Cefazolin 2g IV q6-8h

Duration: 

Initial IV therapy for 2-4 weeks followed by oral therapy. Minimum duration:  6 weeks. Modify according to clinical response.

Antibiotic therapy tailored to tissue/bone C&S result.

4 weeks of IV antibiotics is required for Staphylococcus aureus osteomyelitis associated with bacteraemia.

Conversion from IV to PO therapy with good bioavailability can be done after minimum 2 weeks of IV antibiotics provided:

• Patient has no significant comorbidity

• Uncomplicated infection with source control

• Clinical response seen

• Patient able to tolerate orally

• Suitable oral antibiotics with good oral bioavailability & proven sensitivity to causative organism

A shorter duration of antibiotics can be considered if the osteomyelitis is fully resected (E.g.: amputation with a  clear margin):

• No surrounding soft tissue infection: 5 days.

• Evidence of soft tissue infection: 10-14 days.

Refer to Appendix 3 for antibiotic allergy. 

Empirical therapy should be withheld unless the patient is septic or in patients with neurologic compromise.  

CT-guided needle biopsy & aspiration should be done & specimen sent for C&S.

Cloxacillin 2g IV q4h

Cefazolin 2g IV q6-8h 

Empiric gram negative (3rd or 4th generation cephalosporin) should be covered if patient had: 

• Recent spinal hardware inserted or surgery

• Intra-abdominal infections 

• Co-existing or synchronous genitourinary infection

• Immunocompromised

Antibiotic therapy tailored to tissue/bone C&S result.

Conversion from IV to oral therapy with good bioavailability can be done after minimum 2 weeks of IV antibiotics. 

Duration:

• Minimum 6 weeks. 

• Minimum 8 weeks if undrained paravertebral abscess(es) and/or infection due to drug-resistant organisms.

• Up to 12 weeks if extensive bone destruction or infection due to Brucella sp.

Refer to brucellosis under Tropical Infections section for infection due to Brucella sp.

Cloxacillin 2g IV q4-6h

Antibiotic allergy:

Cefazolin 2g IV q6-8h

OR

Clindamycin 600mg IV q6h, followed by oral therapy (same dose)

OR 

*Vancomycin 15-20mg/kg (actual body weight) IV q8-12h; not to exceed 2g/dose

Drainage, debridement and washout of infected joints is important to limit further damage.

Duration:

Parenteral therapy 2-4 weeks, then oral therapy to complete total 4-6 weeks.

A shorter duration of therapy is possible in immunocompetent patients who have had adequate surgical drainage.

Refer to Appendix 3 for antibiotic allergy.

*Vancomycin: If suspected/confirmed MRSA. Consider loading dose 25-30mg/kg for critically ill or septic patients to achieve faster steady state.

Empirical therapy wherever possible should be directed by the result of the gram stain of the joint aspirate.

To consider gonococcal arthritis In a sexually active patient. Refer to the Sexually Transmitted Infections section.

Initial treatment:

Cloxacillin 2g IV q4-6h

OR

Cefazolin 2g IV q6-8h

PLUS

Rifampicin 300mg PO q12h OR 600mg PO q24h

--

Duration:

2-6 weeks for IV therapy (according to treatment strategy).

Followed by an oral combination therapy according to susceptibility. Rifampicin should be included if the implant is in situ. 

Initial treatment:

*Vancomycin 15-20mg/kg (actual body weight) IV q8-12h; not to exceed 2g/dose

PLUS                                                

Rifampicin 300mg PO q12h OR 600mg PO q24h 

--

Duration:

2-6 weeks for IV therapy (according to treatment strategy)

Followed by an oral combination therapy according to susceptibility. Rifampicin should be included if the implant is in situ.

*Refer to Appendix 1 for vancomycin loading dose.

Intraoperative tissue culture should be taken to guide antibiotic regimen.

Empirical therapy is not recommended unless patient is septic.

Ampicillin/sulbactam 3g IV q6h

--

Treatment concepts:

• Treatment is based on culture and sensitivity.

• In staphylococcal infection, rifampicin should be added in combination with at least one other anti-staphylococcal agent, several days after surgical debridement when implant is retained/exchanged following surgery.

• Treatment strategy and duration of treatment depends on surgical strategy.

Cloxacillin 500mg PO q6h

OR

Cephalexin 1g PO q12h 

Amoxicillin/clavulanate 625mg PO q8h

OR

Ampicillin/sulbactam 375-750mg PO q12h 

Duration: 1-2 weeks*

*10 days following surgical debridement

Amoxicillin/clavulanate 1.2g IV q8h

OR

Ampicillin/sulbactam 3g IV q6h

If pseudomonas is suspected:

** Piperacillin/tazobactam 4.5g IV q6-8h

OR

Cefepime 2g IV q8h

If MRSA is suspected:

***Vancomycin 15-20mg/kg q8-12h; not to exceed 2g/dose 

Cefuroxime 1.5g IV q8h

PLUS

*Metronidazole 500mg IV q8h

Duration for skin & soft tissues involvement:

Total duration 2-4 weeks

Duration for bone/joint involvement: 

• Resected: total duration 2-5 days

• Debrided for infected soft tissue: total duration 1-2 weeks

• Positive culture or histology of bone margins after bone resection: total duration 3 weeks

• No surgery or dead bone: total duration 6 weeks

IV to PO switch can be considered if adequate source control is performed.

*Metronidazole: In ischemia limb / necrosis / gas forming.

**Piperacillin/tazobactam: if given as q8h, to be given as extended infusion (over 3-4 hours)

***Refer to Appendix 1 for vancomycin loading dose.

Refer to Appendix 3 for antibiotic allergy.

Surgical debridement is URGENT for severe infections. Antibiotics should be streamlined based on intraoperative culture and sensitivity.

*Piperacillin/tazobactam 4.5g IV q6-8h

MAY ADD

**Clindamycin 600-900mg IV q8h

Meropenem 1g IV q8h

OR

Imipenem 1g IV q6-8h

MAY ADD

**Clindamycin 600-900mg IV q8h

Duration:

There is a lack of any convincing evidence regarding the ideal duration of antibiotic therapy, which varies between 7 and 14 days. In general, antibiotics should be continued until no further debridement is needed and the patient’s hemodynamic status has normalized.

*Piperacillin/tazobactam: if given as q8h, to be given as extended infusion (over 3-4 hours)

**Clindamycin should be started empirically if there is risk of Group A Streptococcus or presence of gas crepitus. 

Duration: 3-5 days. To stop clindamycin if there is no evidence of Group A Streptococcus.

Benzylpenicillin 2-4MU IV q4h

PLUS

*Clindamycin 600-900mg IV q8h 

--

Duration:

There is a lack of any convincing evidence regarding the ideal duration of antibiotic therapy, which varies between 7 and 14 days. In general, antibiotics should be continued until no further debridement is needed and the patient’s hemodynamic status has normalized.

*If confirmed Group A Streptococcus: Clindamycin & penicillin combination therapy is given until patients are clinically and hemodynamically stable for at least 48 to 72 hours; followed by penicillin monotherapy thereafter.

Ceftriaxone 2g IV q24h

PLUS

Doxycycline 100mg PO q12h 

Ciprofloxacin 400mg IV q8h 

--

Mild:

Benzylpenicillin 4MU IV q4h

PLUS

Clindamycin 600-900mg IV q8h

Moderate to severe:

*Piperacillin/tazobactam 4.5g IV q6-8h

PLUS

Clindamycin 600-900mg IV q8h

--

Aggressive surgical debridement is necessary to remove all necrotic tissue.

 Duration: total 10-28 days

Refer to Urinary Tract Infection and Gastrointestinal Infection sections for other gas forming infections (E.g.: emphysematous pyelonephritis and emphysematous cholecystitis) 

*Piperacillin/tazobactam: if given as q8h, to be given as extended infusion (over 3-4 hours).