Clinical Practice Guidelines

Antibiotics

  •   Infection   Likely organisms Initial antimicrobials1 () = maximum dose Duration of treatment2 and other comments
    CENTRAL NERVOUS SYSTEM/EYE
    Brain abscess

    S. milleri and other streptococci Anaerobes

    Gram-negatives

    S. aureus

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3 and

    Metronidazole 15 mg/kg (1 g) iv stat, then 7.5 mg/kg (500 mg) iv 8 H

    3 weeks minimum

    Penicillin hypersensitivity: substitute Flucloxacillin with Vancomycin 15 mg/kg (500 mg) iv 6 H

    Post-neurosurgery

    As above plus

    S. epidermidis

    As above but substitute Flucloxacillin with Vancomycin 15 mg/kg (500 mg) iv 6 H  
    Encephalitis

    Herpes simplex virus Enteroviruses Arboviruses

    M. pneumoniae

    Aciclovir 20 mg/kg iv 8 H (age <3 months) 500 mg/m2 iv 8 H (age 3 months to 12 years) 10 mg/kg iv 8 H (age >12 years)

    3 weeks minimum

    Consider adding Azithromycin if M. pneumoniae

    suspected

    Meningitis

    Over 2 months of age

    S. pneumoniae4

    N. meningitidis

    H. influenzae type b5

    Third generation cephalosporin3

    S. pneumoniae 10 days

    N. meningitidis 5–7 days

    H. influenzae type b 7–10 days Consider  addition of Dexamethasone

    Over 2 months of age and possibility of penicillin-resistant pneumococci4  (www.snipurl

    .com/vanco)

    As above

    Third generation cephalosporin3 and

    Vancomycin 15 mg/kg (500 mg) iv 6 H

     
    Under 2 months of age

    As above plus Group B streptococci

    E. coli and other Gram-negative coliforms

    L. monocytogenes

    Third generation cephalosporin3 and

    Benzylpenicillin

    Gram-negative 3 weeks

    GBS/Listeria 2–3 weeks

    Substitute Benzylpenicillin with Vancomycin if possibility of  penicillin-resistant pneumococci4

    With shunt infection,

    post-neurosurgery, head trauma or CSF leak

    As for over 2 months of age plus

    S. epidermidis S. aureus

    Gram-negative  coliforms incl.

    P. aeruginosa

    Vancomycin 15 mg/kg (500 mg) iv 6 H and

    Ceftazidime 50 mg/kg (2 g) iv 8 H

    10 days minimum
    Contact prophylaxis N. meningitidis Rifampicin 10 mg/kg (600 mg) po 12 H 2 days (alternatives: see Table 30.3)
    Contact prophylaxis H. influenzae type b Rifampicin 20 mg/kg (600 mg) po 24 H 4 days (alternatives: see Table 30.3)


    Postseptal (orbital) cellulitis

    S. aureus

    H. influenzae spp.

    S. pneumoniae

    M. catarrhalis Gram-negatives Anaerobes

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

    10 days minimum Rule out meningitis

    Consider adding Metronidazole if not responding

    Preseptal (periorbital) cellulitis

    Mild

    Group A streptococci

    S. aureus

    H. influenzae spp.

    Amoxycillin/clavulanate [400/57 mg per 5 mL]

    22.5 mg/kg (875 mg) (Amoxycillin component) =

    0.3 mL/kg (11 mL) po 12 H

    7–10 days

    Consider non-infective cause in trivial cases

    Severe, or not responding, or under 5 years of age and non-Hib immunised As above plus H. influenzae type b5

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

     
    CARDIOVASCULAR

    Endocarditis

    Native valve or homograft

    Viridans streptococci Other streptococci Enterococcus spp.

    S. aureus

    Benzylpenicillin 60 mg/kg (2 g) iv 6 H and

    Gentamicin 2.5 mg/kg (240 mg) iv 8 H* and

    Flucloxacillin 50 mg/kg (2 g) iv 6 H

    4–6 weeks

    *Gentamicin 1 mg/kg (80 mg) iv 8 H for 1–2 weeks when used only for synergy

    (Gentamicin monitoring is generally not required with low

    dose in this setting)

    Artificial valve or post surgery

    As above plus

    S. epidermidis

    Vancomycin 15 mg/kg (500 mg) iv 6 H and

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Gentamicin 2.5 mg/kg (240 mg) iv 8 H*

     

    Endocarditis prophylaxis

    For dental procedures only

    Viridans streptococci

    S. aureus

    S. pneumoniae

    Other Gram-positive cocci

    Enterococcus spp.

    Amoxycillin 50 mg/kg (2 g)

    Local anaesthetic: give po 1 hour before procedure General anaesthetic: give iv with induction

    Penicillin hypersensitivity: substitute Amoxycillin with Clindamycin 20 mg/kg (600 mg) po or iv

     

      Infection   Likely organisms Initial antimicrobials1 () = maximum dose Duration of treatment2 and other comments
    GASTROINTESTINAL

    Diarrhoea

    Salmonella spp. isolated in infant under 3 months of age or in immunocompromised

    Salmonella spp. Third generation cephalosporin3

    5–7 days

    Antibiotic treatment is generally unnecessary for most other organisms

    Antibiotic associated C. difficile Metronidazole 7.5 mg/kg (400 mg) po 8 H 7–10 days
    Giardiasis G. lamblia

    Metronidazole 30 mg/kg (2 g) po daily

    or

    Tinidazole 50 mg/kg (2 g) po

    3 days

     

    Single dose

    Peritonitis or ascending cholangitis Gram-negative coliforms Anaerobes Enterococcus spp. Ampicillin or Amoxycillin 50 mg/kg (2 g) iv 6 H and Gentamicin 7.5 mg/kg (360 mg) iv daily (<10 years) 6 mg/kg (360 mg) iv daily (≥10 years) and Metronidazole 15 mg/kg (1 g) iv stat, then 7.5 mg/kg (500 mg) iv 8 H

    Up to 14 days

    See footnote 6 re Gentamicin dosing/monitoring

    Threadworm (Pinworm) Enterobius vermicularis Mebendazole 50 mg po (<10 kg) 100 mg po (≥10 kg) Single dose; may need to repeat after 14 days Treat whole family
    GENITOURINARY

    Urinary tract infection

    Over 6 months of age and not sick

    E. coli

    P. mirabilis

    K. oxytoca

    Other Gram-negatives

    Trimethoprim 4 mg/kg (150 mg) po 12 H

    or

    if oral liquid is necessary then Co-trimoxazole (Trimethoprim/Sulphamethoxazole  8/40 mg/mL)

    0.5 mL/kg (20 mL) po 12 H

    5 days
    Under 6 months of age or sick or acute pyelonephritis

    As above plus

    Enterococcus spp.

    Benzylpenicillin 60 mg/kg (2 g) iv 6 H and

    Gentamicin 7.5 mg/kg (360 mg) iv daily (<10 years) 6 mg/kg (360 mg) iv daily (≥10 years)

    (For infants under 1 month of age, see doses in

    ‘Septicaemia in neonate’ section)

    5–7 days for UTI

    10–14 days for pyelonephritis

    See footnote 6 re Gentamicin dosing/monitoring

     

    Prophylaxis As above

    Trimethoprim 2 mg/kg (150 mg) po daily

    or

    if oral liquid is necessary then Co-trimoxazole (Trimethoprim/Sulphamethoxazole  8/40 mg/mL)

    0.25 mL/kg (20 mL) po daily

    Routine prophylaxis is no longer recommended
    RESPIRATORY
    Epiglottitis H. influenzae type b5 Ceftriaxone 50 mg/kg (1 g) iv daily 5 days consider addition of Dexamethasone

    Gingivostomatitis

    In immunocompromised

    Herpes simplex virus Aciclovir 500 mg/m2 iv 8H (age 3 months to 12 years) 10 mg/kg iv 8 H (age >12 years)

    7 days

    Treatment is only recommended in the immunocompromised

    Otitis externa

    Acute diffuse

    S. aureus

    S. epidermidis

    P. aeruginosa Proteus spp. Klebsiella spp.

    Topical  steroid/antibiotic drops

    7 days

    Clean ear canal

    (± insertion of wick soaked in drops if ear canal oedematous)

    Acute localised (furuncle) ± cellulitis

    S. aureus

    Group A streptococci

    Flucloxacillin 50 mg/kg (2 g) iv 6 H 5 days
    Failure of first-line treatment, high fever or severe persistent pain

    As above plus

    P. aeruginosa

    Ticarcillin/Clavulanate

    50 mg/kg (3 g) (Ticarcillin component) iv 6 H

    14 days minimum Consider fungal infection
    Otitis media

    Viruses

    S. pneumoniae

    M. catarrhalis

    H. influenzae spp. Group A streptococci

    Consider no antibiotics for 48 hours if over 6 months of age

    or

    Amoxycillin 15 mg/kg (500 mg) po 8 H

       

    5 days

    Consider Amoxycillin/clavulanate after 48 hours if inadequate response to Amoxycillin

    Pertussis B. pertussis

    Azithromycin 10 mg/kg (500 mg)

    or

    Clarithromycin 7.5 mg/kg (500 mg) po 12 H

    5 days

     

    7 days

    Can be given up to 3 weeks after contact with index case or if symptoms <3 weeks


      Infection   Likely organisms Initial antimicrobials1 () = maximum dose Duration of treatment2 and other comments

    Pneumonia

    Mild (outpatient)

    Viruses

    S. pneumoniae

    H. influenzae spp.

    Amoxycillin 25 mg/kg (500 mg) po 8 H 5 days
    Moderate  (inpatient) As above Benzylpenicillin 60 mg/kg (2 g) iv 6 H  
    Severe systemic toxicity or pneumatocoele

    As above plus

    S. aureus

    Group A streptococci Gram-negatives

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

    10 days minimum

    Consider adding Azithromycin 15 mg/kg (500 mg) iv stat, then 5 mg/kg (200 mg) iv daily to cover M. pneumoniae and other atypical pathogens

    Tonsillitis

    Viruses

    Group A streptococci

    Consider no antibiotics (particularly if <4 years)

    or

    Phenoxymethylpenicillin (Penicillin V) 250 mg po 12 H (<10 years) 500 mg po 12 H (≥10 years)

    10 days
    SKIN/SOFT TISSUE/BONE
    Bites (animal/human)

    Viridans streptococci

    S. aureus

    Group A streptococci Oral anaerobes

    E. corrodens

    Pasteurella spp. (cat and dog)

    C. canimorsus (dog)

    Amoxycillin/Clavulanate (400/57 mg/5 mL)

    22.5 mg/kg (875 mg) (Amoxycillin component) 0.3 mL/kg (11 mL) po 12 H

    5 days for infected bite

    For otherwise healthy individuals, antibiotic therapy is usually not necessary for bites with a low risk of infection Check tetanus immunisation status

    If severe, penetrating injuries, esp. involving joints or tendons As above Ticarcillin/Clavulanate 50 mg/kg (3 g) (Ticarcillin component) iv 6 H 14 days

    Cellulitis

    Mild (outpatient)

     

    Group A streptococci

    S. aureus

     

    Cephalexin 25 mg/kg (500 mg) po 6 H

    or

    Cephalexin 33 mg/kg (500 mg) po 8 H

      5–10 days
    Moderate/severe (inpatient) As above Flucloxacillin 50 mg/kg (2 g) iv 6 H  

     

    Facial cellulitis in child under 5 yr of age and non-Hib immunised

    As above plus

    S. pneumoniae

    H. influenzae spp.5

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

     
    Necrotising fasciitis As above

    Vancomycin 15 mg/kg (500 mg) iv 6 H and

    Meropenem 25 mg/kg (1 g) iv 8 H and

    Clindamycin 15 mg/kg (600 mg) iv 8 H

    Consider IVIG
    Head lice Pediculus humanus var. capitis 1% permethrin liquid or cream rinse Repeat after one week
    Impetigo

    Group A streptococci

    S. aureus

    Mupirocin 2% ointment top 8 H if localised

    or

    Cephalexin 33 mg/kg (500 mg) po 8 H

    5–10 days

    Lymphadenitis (cervical)

    Mild

    S. aureus

    Group A streptococci Oral anaerobes

     

    Cephalexin 25 mg/kg (500 mg) po 6 H

    or

    Cephalexin 33 mg/kg (500 mg) po 8 H

      7 days
    Severe As above Flucloxacillin 50 mg/kg (2 g) iv 6 H  

    Osteomyelitis

    Uncomplicated

     

    S. aureus

    Group A streptococci

    S. pneumoniae

      Flucloxacillin 50 mg/kg (2 g) iv 6 H   3 weeks for uncomplicated cases2
    If under 5 yr of age and non-Hib immunised

    As above plus

    H. influenzae type b5

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

     
    In patient with sickle cell anaemia

    As above plus

    Salmonella spp.

    Flucloxacillin 50 mg/kg (2 g) iv 6 H and

    Third generation cephalosporin3

     
    With penetrating foot injury

    As above plus

    P. aeruginosa

    Ticarcillin/Clavulanate 50 mg/kg (3 g) (Ticarcillin component) iv 6 H

    Surgical intervention important

    See footnote 6 re Gentamicin dosing/monitoring Check tetanus immunisation status


      Infection   Likely organisms Initial antimicrobials1 () = maximum dose Duration of treatment2 and other comments
    Scabies Sarcoptes scabiei 5% permethrin cream top

    One application from neck down; may need to repeat after 14 days

    Treat whole family

    Septic arthritis As for osteomyelitis As for osteomyelitis 3 weeks for uncomplicated cases.2 Always consider surgical drainage

    Shingles

    In immunocompromised or involving eye

    Varicella zoster virus

    Aciclovir 500 mg/m2 iv 8H (age 3 months to 12 years) 10 mg/kg iv 8 H (age >12 years) and

    Aciclovir ointment to eye 5 times per day

    7 days

    Shingles in immunocompetent children does not generally require treatment

    SEPTICAEMIA (UNDER 2 MONTHS OF AGE)

    Septicaemia

    Community-acquired  infection

    Group B streptococci

    E. coli and other Gram-negative coliforms

    L. monocytogenes

    H. influenzae spp.5

    plus those listed below for ‘Septicaemia with unknown CSF’

    Benzylpenicillin 60 mg/kg iv 12 H (first week of life)

    6 H (1–4 weeks of age)

    4H (>4 weeks of age) and

    Third generation cephalosporin3

    Add Flucloxacillin 50 mg/kg iv 12 H (first week of life)

    8H (1–4 weeks of age) 6H (>4 weeks of age)

    if infection with S. aureus suspected (e.g. umbilical infection)

    Duration depends on culture results

    Premature neonates require special dosing consideration

    If abdominal source suspected As above plus Anaerobes

    Amoxycillin or Ampicillin 50 mg/kg (2 g) iv 6 H and Gentamicin 5 mg/kg iv 24 H (1st week of life) 7.5 mg/kg iv daily thereafter and

    Metronidazole 15 mg/kg iv stat, then 7.5 mg/kg iv 12 H

     
    SEPTICAEMIA (OVER 2 MONTHS OF AGE)
    Septicaemia with unknown CSF

    S. pneumoniae4

    N. meningitidis

    S. aureus

    Group A streptococci Gram-negatives

    Flucloxacillin 50 mg/kg (2 g) iv 6 H† and

    Third generation cephalosporin3

    †Substitute Flucloxacillin with Vancomycin 15 mg/kg (500 mg) iv 6 H if central line in situ or suspected MRSA infection

    Consider adding IVIG and Clindamycin 10 mg/kg (600 mg) iv 6 H if suspect Gram-positive toxic shock syndrome

    Duration depends on culture results


    Septicaemia with normal CSF As above

    Flucloxacillin 50 mg/kg (2 g) iv 6 H† and

    Gentamicin 7.5 mg/kg (360 mg) iv daily (<10 years) 6 mg/kg (360 mg) iv daily (≥10 years)

     
    In non-Hib immunised

    As above plus

    H. influenzae type b5

    Flucloxacillin 50 mg/kg (2 g) iv 6 H† and

    Third generation cephalosporin3

     
    In neutropenic patient

    As above plus

    Enterococcus spp.

    P. aeruginosa

    Piperacillin/Tazobactam 100 mg/kg (4 g) (Piperacillin component) iv 6H and

    Amikacin 22.5 mg/kg (1.5 g) iv daily (<10 years)

    18 mg/kg (1.5 g) iv daily (≥10 years)

    Local protocols for fever and neutropenia may differ

       

    Target trough (<2 mg/L pre 3rd dose)

    In neutropenic patient with potential line infection As above plus Gram-positive cocci incl. S. epidermidis

    Piperacillin/Tazobactam as above and

    Amikacin as above and consider Vancomycin 15 mg/kg (500 mg) iv 6 H

     


    Notes to antimicrobial guidelines


    Further information available at  www.snipurl.com/RCHantibiotics.

    These guidelines have been developed to assist doctors with their choice of initial empiric treatment. Except where specified, they do not apply to neonates or immunocompromised patients. Always ask about previous hypersensitivity reactions to antibiotic. The choice of antimicrobial, dose and frequency of administration for continuing treatment may require adjustment according to the clinical situation. The recommendations are not intended to be prescriptive and alternative regimens may also be appropriate.

    1 Antimicrobial choice and dose

     
    Antibiotics should be changed to narrow spectrum agents once sensitivities are known.
    Dose adjustments may be necessary for neonates, and for children with renal or hepatic impairment. Alternative antimicrobial regimens may be more appropriate for neonates, immunocompromised patients or others with a special infection risk (e.g. cystic fibrosis, sickle cell anaemia).

    Resistance to antimicrobials is an increasing problem worldwide. Of particular concern is the increasing inci- dence of penicillin-resistant pneumococci (see footnote 4). It is important to take into account local resistance patterns when using these guidelines.


    2 Duration of treatment


    Duration of treatment is given as a guide only and may vary with the clinical situation. ‘Step down’ from intra- venous to oral treatment is appropriate in many cases. Durations given generally refer to the minimum total intravenous and oral treatment.

    3 Third  generation cephalosporins  


    Cefotaxime: 50 mg/kg (2 g) iv 6 H
    Ceftriaxone: usual 50 mg/kg (2 g) iv daily; severe (including meningitis and brain abscess) 100 mg/kg (2 g) iv daily or 50 mg/kg (1 g) iv 12 H
    NB. Ceftriaxone should be avoided in neonates, particularly if <41 weeks gestation, jaundiced or receiving calcium containing solutions, including TPN.

    4 Penicillin-resistant  pneumococci  (www.snipurl.com/vanco)  


    The prevalence of invasive strains that are highly resistant to Penicillin or cephalosporins in Melbourne remains low. A third generation cephalosporin remains the drug of first choice for the empiric treatment of meningitis. However, Vancomycin should be added if S. pneumoniae is suspected (www.snipurl.com/vanco). This should be stopped if sensitivity to a third generation cephalosporin is shown, as will be the case with most isolates. The prevalence of resistant strains is being monitored and this recommendation may change.
    Penicillin remains the drug of first choice for the empiric treatment of suspected pneumococcal pneumonia and other non-CNS infections, regardless of susceptibility. High doses of penicillin overcome resistance in this setting and should be used for confirmed non-CNS infection caused by penicillin-resistant pneumococci.

    5 Invasive H. influenzae type b disease

     
    Since the introduction of H. influenzae type b (Hib) immunisation, there has been a dramatic decline in the incidence of invasive disease. However, in children with potential invasive disease, who are not fully immunised against Hib, therapy should include cover against Hib. 


    6 Gentamicin   dosing/monitoring


    Once-daily administration of Gentamicin is safe and effective for most patients. Certain patients, such as neonates and those with cystic fibrosis, endocarditis or renal failure, may require special dosing consideration.
    The regimen for monitoring Gentamicin levels is different for once-daily and 8, 12 or 18 H dosing, and depends on renal function:


    Once-daily dosing


    Normal renal function – if the patient is to have more than 3 doses, the trough level (pre-dose) should be checked before the third dose and then every 3 days (target level <1 mg/L).
    Abnormal renal function – trough levels may need to be checked earlier and more frequently (target level
    <1 mg/L). 

    Renal failure – levels should be checked post-dose at 2, 12 and 24 hours, and adjusted accordingly. The results should be discussed with a specialist familiar with therapeutic drug monitoring.


    8, 12 and 18 hourly dosing


    The trough level should be checked before the fourth dose, and peak level 1 hour after the start of the fourth dose (target trough <2 mg/L, target peak 5–10 mg/L).
    Levels should be repeated every 3 days, or more frequently if levels are inappropriate or if renal function is abnormal.