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Antimicrobial prescribing guidelines

General information | Sepsis | Central Nervous System Infections | Respiratory Tract Infections | Genito-urinary Tract Infections | Skin and Soft Tissue Infections | Bone and Joint Infections | Surgical Site Infections | Gastrointestinal Tract and Intra-abdominal InfectionsVancomycin and Gentamicin | HIV nPEP

General information

About the Metro South Health antimicrobial prescribing guidelines

This is a guideline for empiric therapy for common and serious bacterial infections in Adults. Not all clinical problems are covered. Ongoing therapy should be adjusted according to microbiology results as they become available - if you cannot see a suitable option reported on Auslab, please call the microbiology lab for advice. For children, see the Children’s Health Queensland Antimicrobial Prescribing Guidelines.

In general, the recommendations for antibiotic use follow the Therapeutic Guidelines (eTG): Antibiotic (version 15, 2014). In some instances (including for community-acquired pneumonia, febrile neutropenia and cellulitis), recommendations differ due to local susceptibility results*, LAM restrictions or the antimicrobial restriction policy (a component of the antimicrobial stewardship program).

*Local susceptibility results (antibiograms via QHEPS intranet):

If your patient has renal impairment, adjust doses as recommended by eTG:Antibiotic Table 2.33 “Antimicrobial doses for in adults with impaired renal function”.

Sepsis

For information on the non-antibiotic management of sepsis, see page 76 of the 2015 PA Hospital Prescribing Guidelines (QHEPS intranet). For patients with an identified source of sepsis, use antibiotics recommended for that source.

Community-onset severe sepsis with no obvious source

gentamicin IV (PDF, 91.25 KB)
&
flucloxacillin 2 g IV 4-hourly
&
vancomycin (PDF, 114.06 KB) 30 mg/kg of total body weight IV loading dose then 15mg/kg IV 12-hourly (round to nearest 250mg)

In patients with non-immediate penicillin hypersensitivity, replace flucloxacillin with: cephazolin 2 g IV 6-hourly.

In patients with immediate penicillin hypersensitivity, omit flucloxacillin or cephazolin.

Hospital-acquired sepsis - unknown source

Early consultation with Infectious Diseases is recommended.

piperacillin-tazobactam 4.5 g IV 8-hourly

For patients known to be colonised with MRSA or have a central-line in situ, add:

vancomycin (PDF, 114.06 KB) 30 mg/kg of total body weight IV loading dose then 15 mg/kg IV 12-hourly (round to nearest 250 mg)

For severe sepsis, consider adding to the above regimen: gentamicin IV (PDF, 91.25 KB).

Febrile neutropenia

gentamicin IV (PDF, 91.25 KB)
&
piperacillin-tazobactam 4.5 g IV 6-hourly

For penicillin hypersensitivity and ongoing therapy, see the PA Hospital Febrile Neutropenia Guidelines (QHEPS intranet).

For management of Febrile Neutropenia, please see the Initial Management of Febrile Neutropenia Flowchart (PDF, 99.95 KB).

Omit gentamicin in patients with amyloidosis.

Haemodialysis patients with presumed sepsis

See PA Hospital Haemodialysis Patient with Acute Febrile Illness, Rigors, or Otherwise Unexplained Hypotension or Instability (01416) (QHEPS intranet).

Central Nervous System Infections

Infectious Diseases consultation recommended.

Community-acquired bacterial meningitis (including suspected)

Empiric treatment of suspected community-acquired bacterial meningitis should not be delayed for the collection of CSF, however blood cultures should be collected prior to the initiation of antibiotics.

dexamethasone 10 mg IV before or with the first dose of antibiotic, then 10 mg 6-hourly IV for 4 days for confirmed cases of Haemophilus or pneumococcal meningitis
&
ceftriaxone 2g IV 12-hourly

If the patient is over 50 years of age, immunocompromised, pregnant or has a history of alcohol abuse; to treat potential Listeria infection, ADD:

benzylpenicillin 2.4 g IV 4-hourly

If gram-positive cocci are seen on the gram stain of CSF; to treat the possibility of pneumococcus with reduced susceptibility to ceftriaxone, ADD:

vancomycin (PDF, 114.06 KB) 30 mg/kg of total body weight IV loading dose then 15mg/kg 12-hourly (round to nearest 250mg)

For patients with immediate penicillin or cephalosporin hypersensitivity, use:

vancomycin (PDF, 114.06 KB) 30 mg/kg of total body weight IV loading dose then 15mg/kg IV 12-hourly (round to nearest 250mg)
&
ciprofloxacin* 400 mg IV 8-hourly                                         *ID approval required

Healthcare-associated meningitis

For meningitis following neurosurgery, spinal surgery, cranial trauma, insertion of an intracranial device or in patients with ventricular stunts, use:

vancomycin (PDF, 114.06 KB) 30 mg/kg of total body weight IV loading dose then 15mg/kg 12-hourly (round to nearest 250mg)
&
meropenem* 2 g IV 8-hourly                                                 *ID approval required

For patients with immediate penicillin or cephalosporin hypersensitivity, seek Infectious Disease advice.

Joint Neurosurgery and Infectious Diseases management recommended.

Respiratory Tract Infections

Community-acquired pneumonia (CAP)

A careful assessment of pneumonia severity will act as a guide for decisions about patient management including antibiotic therapy. It is particularly important to taken in to account patient age, pre-existing medical co-morbidities, state of immunosuppression and the presence of clinical features of organ system failure. CORB and SMART-COP scores can be used as an aid when assessing the severity of pneumonia. For most patients, a total of 5-7 days therapy is appropriate. If a specific pathogen is detected, see the eTG:Antibiotic - Antibiotic (Respiratory tract infections: directed therapy for pneumonia) for treatment recommendations.

Mild CAP

amoxycillin 1g PO 8-hourly
OR (if atypical organism suspected or penicillin hypersensitivity)
doxycycline 100mg 12-hourly
OR roxithromycin 300mg PO daily

If the patient is not improving by 48 hours, or if clinical review within 48 hours is not possible, consider using dual therapy with amoxycillin plus either doxycycline or roxithromycin.

Moderate CAP

benzylpenicillin 1.2 g IV 6-hourly followed by amoxycillin 1 g PO 8-hourly
& EITHER
roxithromycin 300 mg PO daily
OR
doxycycline 100 mg PO 12-hourly

For patients with non-immediate penicillin hypersensitivity, substitute penicillin with:

ceftriaxone 1 g IV daily followed by cefuroxime 500 mg PO 12-hourly

In patients with immediate penicillin hypersensitivity, use as a single agent:

moxifloxacin 400 mg PO daily

Switch from IV to oral therapy as soon as patients have clinically improved. If Legionella pneumonia is strongly suspected or confirmed, discuss with Infectious Diseases.

Severe CAP

benzylpenicillin 1.2 g IV 4-hourly
&
gentamicin IV (PDF, 91.25 KB)
&
azithromycin 500 mg IV daily for up to 3 days

Gram-negative sepsis can masquerade as severe community-acquired pneumonia, therefore gentamicin is included as empiric therapy in this regimen. Gentamicin can be ceased when gram-negative sepsis is excluded.

For patients with non-immediate penicillin hypersensitivity, substitute penicillin with:

ceftriaxone 1 g IV daily followed by cefuroxime 500 mg PO 12-hourly (gentamicin is not required)

In patients with immediate penicillin hypersensitivity, use a single agent:

moxifloxacin 400 mg IV/PO daily

If Legionella pneumonia is strongly suspected or confirmed, discuss with Infectious Diseases.

Seek Infectious Diseases advice:

  • if the patient has recently been in a tropical region (e.g. FNQ or NT) as melioidosis may need to be considered
  • for management of pneumonia in an immunocompromised patients as Pneumocystis or other pathogens may need to be considered.

Community-acquired aspiration pneumonia

For patients with mild disease, use:

amoxycillin 1 g PO 8-hourly

For more severe disease, use:

benzylpenicillin 1.2 g IV 6-hourly
&
metronidazole 400 mg PO or 500 mg IV 12-hourly

For patients with penicillin hypersensitivity, as a single agent use:

clindamycin 450 mg PO 8-hourly
OR
lincomycin 600 mg IV 8-hourly

Treat for 5 to 7 days.

Hospital-acquired pneumonia, including aspiration pneumonia

For patients with mild disease, use:

amoxycillin+clavulanate 875+125 mg PO 12-hourly

For more severe disease, use:

piperacillin-tazobactam 4.5 g IV 8-hourly

For patients with non-immediate penicillin hypersensitivity, use:

ceftriaxone 1 g IV daily
& if anaerobic infection is suspected, add:
metronidazole 400 mg PO or 500 mg IV 12-hourly

Treat for 5 to 7 days.

Seek Infectious Diseases advice if the patient:

  • has previous isolates with resistance to piperacillin – tazobactam, or
  • is colonised with MRSA, or
  • has immediate penicillin hypersensitivity, or
  • is immunocompromised.

Exacerbations of COPD

Bronchodilators and corticosteroids are the mainstay of therapy, if antibiotics are required use:

amoxycillin 500 mg PO 8-hourly
OR
doxycycline 200 mg PO initially, then 100 mg PO daily

Treat for 5 days. Antibiotics do not need to be changed based on sputum culture results unless the patient is progressively unwell.

Genito-urinary Tract Infections

Acute, uncomplicated UTI

trimethoprim 300mg PO daily for 3 days in non-pregnant women or 7 days in men

Adjust therapy according to susceptibility results if organism isolated is resistant to empiric therapy.

Acute pyelonephritis

gentamicin IV (PDF, 91.25 KB)
&
amoxycillin 2 g IV 6-hourly

For patients with immediate penicillin hypersensitivity, omit amoxycillin. Change to oral antibiotics when clinically well and susceptibility results are available. Treat for a total of two weeks.

Asymptomatic bacteriuria

This is common in elderly patients and no treatment is required.

See eTG:Antibiotic (Urinary infections – Asymptomatic bacteriuria) for further discussion and rationale.

Catheter associated bacteriuria and UTI

Urine culture and treatment should only be undertaken if the patient has signs of systemic infection (e.g. fever, rigors), if the patient has risk factors (e.g. neutropenia, transplantation, pregnancy), or before urological surgery.

If treatment is indicated, select antibiotics based on susceptibility results and treat for 10 – 14 days. Change the IDC or remove it if possible.

Mild to moderate sexually-acquired PID

azithromycin 1 g PO stat + repeat dose at one week
&
metronidazole 400 mg PO 12-hourly for 14 days
&
if gonococcal infection is suspected, add:
ceftriaxone 500 mg in 2 mL of 1% lignocaine IM, or 500 mg IV, as a single dose

For immediate type penicillin or cephalosporin hypersensitivity, seek Infectious Diseases or Sexual Health advice.

Mild to moderate non-sexually acquired PID

amoxycillin+clavulanate 875+125 mg PO 12-hourly
&
azithromycin 1 g PO stat + repeat dose at one week

Treat for 14 days.

For patients with penicillin hypersensitivity, substitute amoxycillin+clavulanate with:

metronidazole 400 mg PO 12-hourly

Pregnant women

Acute, uncomplicated UTI:

cephalexin 500 mg PO 12-hourly for 5 days

Acute pyelonephritis:

ceftriaxone 1 g IV Daily

Change to oral antibiotics based on susceptibility results when afebrile and clinically well. Treat for a total of two weeks.

Severe PID (sexually-acquired or non-sexually acquired)

ceftriaxone 2 g IV daily
&
azithromycin 500 mg IV daily
&
metronidazole 500 mg IV 12-hourly

For immediate type penicillin or cephalosporin hypersensitivity seek Infectious Disease or Sexual Health advice.

If clinical improvement after 48 hours, change to oral regimen for mild to moderate infection above to complete a total treatment duration (IV+oral) of 2 weeks.

Sexual partners need to be tested and treated to avoid reinfection. For more information regarding PID please call Princess Alexandra Hospital Sexual Health (07) 3176 5881.

Skin and Soft Tissue Infections

Cellulitis

Refer to the Metro-South Cellulitis Pathway (PDF, 188.48 KB) procedure for the management of cellulitis.

Boils

Incision and drainage is usually the only treatment required.

If the lesion is large (> 5cm), there is associated cellulitis or systemic symptoms antibiotics are also indicated. In Metro South hospitals > 50% of such lesions are caused by non-multiresistant MRSA therefore, use:

trimethoprim+sulfamethoxazole 160+800 mg PO 12-hourly for 5 days.

For patients with sulfonamide allergies or other contra-indications to trimethoprim+sulfamethoxazole, use:

clindamycin 450 mg PO 8-hourly for 5 days.

Bone and Joint Infections

Infectious Diseases consultation is recommended for all bone and joint infections.

Long-bone osteomyelitis or septic arthritis

flucloxacillin 2 g IV 6-hourly

For non-immediate penicillin hypersensitivity, use:

cephazolin 2 g IV 8-hourly.

For immediate penicillin hypersensitivity or if MRSA is suspected, use:

vancomycin (PDF, 114.06 KB)* 30 mg/kg of total body weight IV loading dose then 15 mg/kg 12-hourly (round to nearest 250 mg)           *ID approval required

Vertebral osteomyelitis

Collection of bone or pus specimens for culture and histopathology is critical. If possible, specimens should be collected before antibiotics are administered. However, the results of cultures are often still positive even after administration of antibiotics, so an early biopsy should be pursued even if antibiotics have been started. In vertebral osteomyelitis, open surgical biopsy is more likely to result in a diagnosis than needle biopsy.

Although Staphylococcus aureus is the commonest cause, a significant proportion of cases are caused by gram-negative bacteria, such as E.coli or Pseudomonas aeruginosa. For empiric therapy, use:

piperacillin-tazobactam* 4.5 g IV 8-hourly             *ID approval required
&
vancomycin (PDF, 114.06 KB)* 30 mg/kg of total body weight IV loading dose then 15 mg/kg IV 12-hourly (round to nearest 250 mg)          *ID approval required

Open fractures

For Gustilo open fracture classification I & II (no severe tissue damage or clinical evidence of infection), use:

cephazolin 2 g IV 8-hourly

For immediate penicillin hypersensitivity, use:

lincomycin 600 mg IV 8-hourly

If debridement occurred within 8 hours of injury, continue prophylaxis for 24 to 72 hours. If debridement occurred greater than 8 hours after injury, continue presumptive treatment for 7 days.

For Gustilo open fracture classification III (severe tissue damage or clinical evidence of infection), Infectious Diseases consultation is recommended. Use:

piperacillin-tazobactam 4.5 g IV 8-hourly

For non-immediate penicillin hypersensitivity, use:

cephazolin 2 g IV 8-hourly
&
metronidazole 500 mg IV (or 400 mg PO) 12-hourly

For immediate penicillin hypersensitivity, or if there has been significant fresh or salt water exposure, use:

ciprofloxacin 400 mg IV 8-hourly
&
lincomycin 600 mg IV 8-hourly

When oral medications feasible, change to:

ciprofloxacin 750 mg PO 12-hourly
&
clindamycin 450 mg PO 8-hourly

Continue antibiotic therapy for 7 days.

Diabetic foot infection

For mild to moderate infection with no osteomyelitis or septic arthritis:

amoxycillin+clavulanate 875+125 mg PO 12-hourly

For non-immediate penicillin hypersensitivity, use:

cephalexin 500 mg PO 8-hourly
&
metronidazole 400 mg PO 12-hourly

For immediate penicillin hypersensitivity use:

clindamycin 450 mg PO 8-hourly
&
ciprofloxacin* 500 mg PO 12-hourly                    *ID approval required

For osteomyelitis or severe limb or life threatening infection, initiate:

piperacillin-tazobactam 4.5 g IV 8-hourly

For penicillin hypersensitivity:

lincomycin 600 mg IV 8-hourly
&
ciprofloxacin* 500 mg PO 12-hourly                     *ID approval required

Surgical Site Infections

Surgical site infections

Depending on severity, use:

dicloxacillin 500 mg PO 6-hourly
OR
flucloxacillin 2 g IV 6-hourly

If the surgery involved the gastrointestinal or the genital tract, use:

amoxycillin+clavulanate 875+125 mg PO 12-hourly
OR
piperacillin-tazobactam* 4.5 g IV 8-hourly                      *ID approval required

For severe infections and penicillin hypersensitivity, consult Infectious Diseases.

Gastrointestinal Tract and Intra-abdominal Infections

Periodontal abscess

amoxycillin 500 mg PO 8-hourly for 5 days

For penicillin hypersensitivity use:

clindamycin 300 mg PO 8-hourly for 5 days

Patients should be referred to their dentist for further management.

Clostridium difficile infection

Infectious Diseases consultation recommended.

For mild to moderate disease, use:

metronidazole 400 mg PO 8-hourly for 10 days

For severe disease, use:

vancomycin* 125mg PO 6-hourly                  *ID Consultation required
NB: for inpatient use or where patients have feeding tubes (e.g. nasogastric, PEG) IV product is to be given enterally

Peritonitis, cholangitis or severe diverticulitis

gentamicin IV (PDF, 91.25 KB)
&
amoxycillin 2 g IV 6-hourly
&
metronidazole 500 mg IV 12-hourly (may be omitted in cholecystitis or cholangitis without biliary obstruction)

If IV therapy is required beyond 48 hours, or gentamicin is contraindicated, change to:

piperacillin-tazobactam 4.5 g IV 8-hourly

For non-immediate penicillin hypersensitivity use:

ceftriaxone 1 g IV daily
&
metronidazole 500 mg IV 12-hourly

For immediate penicillin hypersensitivity, seek Infectious Diseases advice.

Spontaneous bacterial peritonitis in patients with ascites

ceftriaxone 2 g IV daily

For patients on fluoroquinolone or trimethoprim+sulfamethoxazole prophylaxis, to cover enterococci:

ADD benzylpenicillin 1.2 g IV 6-hourly
OR use piperacillin-tazobactam 4.5 g IV 8-hourly as a single agent

For immediate penicillin or cephalosporin hypersensitivity, seek Infectious Diseases advice.

Peritonitis in a CAPD patient

See Statewide Peritoneal Dialysis Peritonitis Clinical Pathway.

Vancomycin and Gentamicin

Vancomycin and Gentamicin dosing and monitoring

HIV nPEP

Non-occupational Post-Exposure Prophylaxis (nPEP) for HIV is provided by the larger Metro South Hospitals. It is generally initiated through the Emergency Departments, with early follow-up by PASH (PA Sexual Health).

Local guidelines

Note, these guidelines do not apply to PEP after occupational exposure to HIV.

Last updated 19 December 2016
Last reviewed 17 June 2016

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