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Staphylococcal aureus Bacteraemia Management

(November 2007)

(Download  Staphylococcal aureus Bacteraemia Management _2007.pdf)

This document describes expert recommendations relating to management of Staph. aureus bacteraemia. These guidelines apply to all facilities managed by Hunter New England Health Service. 

Executive Summary

Staph. aureus is a major cause of community and hospital-associated infection with an attributable mortality around 7-10%1. Overall complication rates are high – 24%2. Post treatment relapse of infection due to haematogenous complications occurs in 5-13% of patients (most commonly endocarditis followed by septic arthritis and vertebral osteomyelitis) and may present up to 3 months after the original bacteraemia1,2,3. Relapse rates may be reduced but not eliminated by following the antibiotic, dosage and duration recommendations provided in this guideline. However, late relapse cannot be predicted and may occur even after prolonged initial IV therapy.

This CPG describes important aspects of clinical management, indications for Infectious Disease review, recommended investigations and antibiotic selection, dosage and duration. NB. For all paediatric, complex or relapsed cases, liaison with Infectious Diseases is recommended.

 

Clinical evaluation and usual therapy

Blood culture isolates of coagulase positive Staph. (Staph. aureus or methicillin-resistant Staph. aureus, MRSA) should NEVER be dismissed as contaminants without proper clinical evaluation and if necessary later review with repeat blood cultures. The Clinical Microbiologist (49214444) is available to assist in determining the significance of these isolates.

In both Community and Hospital settings, patients with bacteraemia due to Staph. aureus determined to be significant require the following measures:

  • Evaluation to determine the primary focus of infection and septic complications if present. If musculo-skeletal pain present, especially in the elderly, consider bone scan to detect osteomyelitis.
  • Removal of existing intravascular devices as soon as possible. The risk of developing haematogenous complication increases by 13% for each day that the infected line is left in4. Furthermore, attempts to salvage long-term lines with antibiotic locks should be avoided- the success rate is < 20%.
  • 4 weeks intravenous therapy with flucloxacillin (vancomycin for MRSA) see below for doses (Peripherally-inserted central catheter, PICC is preferred for iv access) unless indications for short course treatment are satisfied.
  • Early cardiological consultation/discussion (Cardiologist or suitably experienced General Physician) when any question of endocarditis arises (do not assume that this has happened just because the patient has had an echocardiogram (transthoracic or transoesophageal).
  • Repeat blood cultures 72 hours after commencing appropriate therapy. If still culture positive, Infectious Diseases consultation is recommended.
  • Provision and discussion of the Staph. aureus Bacteraemia Information Card prior to hospital discharge.
  • Clinical review 1 month after completion of therapy

Indications for Infectious Diseases Consultation

Infectious Diseases consultation is recommended in the following situations:

  • All paediatric cases
  • Slow settling of temperature on treatment (ie > 4 days) or persistently positive blood cultures taken > 72 hrs after commencement of antibiotics.
  • Bone and joint disease
  • Relapse within 3 months of completion of initial treatment.
  • Presence of foreign material (ie prosthesis or other implanted material).

The Area on-call Infectious Diseases Service is available via the John Hunter Hospital switch (49213000).

Antibiotic Selection, Doses and Monitoring

Antibiotic choice 

Empiric therapy

(suspected or possible Staph. aureus infection; lab confirmation awaited)

Directed therapy

 

(Laboratory-confirmed identification and susceptibility)Heading

Community-associated event:

  • Flucloxacillin IV
  • Add vancomycin if patient known to be colonised with MRSA or patient has septic shock.
  • Gentamicin is added if the patient has sepsis of uncertain source/ cause.

Methicillin-susceptible Staph. aureus :

  • Flucloxacilin IV
  • Cephalothin IV for minor betalactam allergy.

Healthcare-associated event:

  • Intensive care unit patient: vancomycin IV
  • Non-intensive care patient: vancomycin IV in major hospitals, flucloxacillin in smaller facilities.
  • Gentamicin may also be indicated for Gram negative cover in some situations.

Methicillin-resistant Staph. aureus (MRSA) :

  • Vancomycin IV

Intravenous Antibiotic Doses f

Antibiotic

Initial estimated GFR

>50mL/min

GFR 10-50mL/min

OR patient on CRRT

 GFR < 10mL/min
Flucloxacillin

2g 6 hrly  

child 50mg/kg 4-hrly

2g 6-hrly

child 50mg/kg 6-hrly

1g 6-hrly

child 25mg/kg 6-hrly

Cephalothin

2g 4-hrly

child 50mg/kg 4-hrly

2g 6-hrly  

child 50mg/kg 6-hrly

1g 6-hrly  

child 25mg/kg 6-hrly

Vancomycin*

(maximum rate of infusion 1g per hour)

50mg/kg (use actual body weight) up to maximum 3 grams per day in two or three divided doses*

Child 30mg/kg up to 1g 12-hrly

 25mg/kg up to 1g every 1-3 days* 25mg/kg up to 1g every 4-10days*

f Monotherapy is standard. The addition of gentamicin is not shown to improve outcome and is not routinely recommended.

* Vancomycin notes:

  • If total calculated dose is greater than 2g/d then give 8-hourly dosing
  • Repeat doses are guided by measured trough level, aiming for trough of 10-20mg/L.
  • In patients with estimated GFR> 50mL/min, check trough prior to 4th dose.
  • In patients with abnormal or changing renal function, measure trough levels frequently so that dosing can be optimised. Advice on vancomycin drug dosing is available via Clinical Microbiology, HAPS (02 49214000).

Indications for short course (2 weeks) therapy

The following patients can be considered for shortened therapy (2 weeks intravenous therapy) if ALL of the following criteria are met:

  • No diagnosed deep focus of infection.
  • Line source if present removed within 48 hrs of diagnosis
  • No evidence of regurgitant valvular lesions or vegetations on transthoracic echocardiogram (see Section 5 below).
  • Blood cultures taken after 72 hours of antibiotics are negative.
  • Patient is NOT receiving renal dialysis (these patients are at high risk of relapse after short course therapy).

Indications for Transoesophageal echocardiography (TOE)

A TOE study should be considered for patients who have:

  • a prosthetic valve, or
  • high risk predisposing cardiac lesion known or demonstrated on transthoracic echo (mitral valve prolapse, rheumatic heart disease, congenital heart disease), or
  • degenerative valvular disease (eg. aortic or mitral regurgitation) or
  • community-associated Staph. aureus bacteraemia with no predisposing factors or apparent focus and a negative transthoracic study.

Patient Education

All patients with Staph. aureus bacteraemia require education about the risk of relapse and the need for early medical attention for possible symptoms of relapse (see Patient Information Sheet below). Where possible each patient should receive medical review one month after completion of treatment.

MRSA Decolonisation

Patients with MRSA bacteraemia should be considered for a decolonisation procedure- this should be discussed with the Infectious Diseases or Microbiology team who will provide necessary instruction about the methods. Decolonisation may proceed during treatment for bacteraemia, provided that there is no complex infected focus, indwelling medical device or chronic ulcer/wound.

Patient Information Sheet (available via EDRS system)

References

  1. Fowler et al. Outcome of Staphylococcus aureus bacteremia according to compliance with recommendations of infectious diseases specialists: experience with 244 patients. Clinical Infectious Diseases 1998;27(3):478-86.
  2. Jernigan J, Farr B Short-course therapy of catheter-related Staphylococcus aureus bacteraemia: a meta-analysis. Ann Intern Med. 1993 Aug 15;119(4):304-11.
  3. Chang et al. Staphylococcus aureus bacteraemia: recurrence and the impact of antibiotic treatment in a prospective multicenter study. Medicine (Baltimore). 2003 Sep;82(5):333-9.
  4. Fowler VG Jr, Justice A, Moore C, Benjamin DK Jr, Woods CW, Campbell S, Reller LB, Corey GR, Day NP, Peacock SJ. Risk factors for hematogenous complications of intravascular catheter-associated Staphylococcus aureus bacteremia. Clin Infect Dis. 2005 Mar 1;40(5):695-703