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Antibiotics: choices for common infections

The following information is a consensus guide. It is intended to aid selection of an appropriate antibiotic for typical patients with infections commonly seen in general practice. Individual patient circumstances and local resistance patterns may alter treatment choices.

Antibiotic use in New Zealand is higher per head of population than in many similar developed countries. Increased antibiotic use leads to the development of resistance by eliminating antibiotic-susceptible bacteria and leaving antibiotic-resistant bacteria to multiply. Antimicrobial stewardship aims to limit the use of antibiotics to situations where they deliver the greatest clinical benefit. Along with infection control, this is the key strategy to counter the emerging threat of antimicrobial resistance.

General principles of antimicrobial stewardship:

  1. In most cases, only prescribe antibiotics for bacterial infections if:
    • Symptoms are significant or severe
    • There is a high risk of complications
    • The infection is not resolving or is unlikely to resolve
  2. Select the first-line indicated antibiotic at the recommended dose and duration
  3. Reserve broad spectrum antibiotics for indicated conditions only
  4. Prioritise consideration of antibiotic resistance over palatability issues and convenience of dosing regimens when deciding which antibiotic to prescribe
  5. Educate patients about responsible use of antibiotics, including when an antibiotic is not indicated

Information on national antimicrobial resistance patterns is available from the Institute of Environmental Science and Research Ltd (ESR), Public Health Surveillance: www.surv.esr.cri.nz

Regional resistance patterns may vary; check with your local laboratory.

To check the subsidy status of a medicine, refer to the New Zealand Formulary: www.nzformulary.org or the Pharmaceutical Schedule: www.pharmac.govt.nz/tools-resources/pharmaceutical-schedule/

Respiratory

COPD – acute exacerbations

Management

Antibiotic treatment is usually only necessary for patients with moderate to severe signs and symptoms of infection.

Approximately half of COPD exacerbations are triggered by viruses rather than bacteria. Antibiotic treatment is more likely to be helpful in patients with clinical signs of chest infection (e.g. purulent sputum and increased shortness of breath and/or increased volume of sputum) and those with more severe airflow obstruction at baseline.

Common pathogens

Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis

Antibiotic treatment - Acute exacerbation of COPD with moderate to severe signs of infection

First choice

Amoxicillin

Adult: 500 mg, three times daily, for five days*

Alternatives

Doxycycline

Adult: 200 mg, on day one (loading dose), followed by 100 mg, once daily, on days two to five*


* Longer courses may not provide additional clinical benefit

Pertussis (Whooping cough)

Management

Antibiotic treatment is recommended to reduce transmission, if initiated within three weeks of the onset of the cough; after this time most people are no longer infectious.

Antibiotic treatment is also recommended if the duration of the cough is unknown, and for pregnant women with pertussis.

Prophylactic antibiotics are recommended for high risk contacts: children aged less than one year and their caregivers, pregnant women and people at risk of complications, e.g. severe asthma, immunocompromised.

Antibiotic treatment is unlikely to alter the clinical course of the illness, unless given within the first few days of contracting the infection. However, as initial symptoms are often indistinguishable from a minor respiratory infection, antibiotics are not usually considered early on unless there is reason to suspect pertussis infection, e.g. family contacts.

Patients should be advised to avoid contact with others, especially infants and children, until at least five days of antibiotic treatment has been taken. Children with pertussis can deteriorate rapidly and may require hospitalisation.

Pertussis is a Notifiable Disease. Suspected cases must be notified to the Medical Officer of Health. Check with the local Medical Officer of Health as to whether laboratory testing is appropriate.

Common pathogens

Bordetella pertussis

Antibiotic treatment - Pertussis symptoms < 3 weeks or high risk contact

First choice

Azithromycin*

Child < 45 kg: 10 mg/kg/dose, once daily, on day one, followed by 5 mg/kg/dose, once daily, on days two to five

Adult and Child > 45 kg: 500 mg on day one, followed by 250 mg, once daily, on days two to five

* Macrolide antibiotics are associated with a risk of development of hypertrophic pyloric stenosis in infants aged under two weeks. However, the benefits of treating pertussis outweigh this risk; azithromycin is the preferred macrolide during pregnancy, lactation and in infants aged < 1 month.

Alternatives

Erythromycin*

Child: 10 mg/kg/dose, four times daily, for 14 days

Adult: 400 mg, four times daily, for 14 days

* See note above re. macrolides


Trimethoprim + sulfamethoxazole (for adults and children aged > 6 weeks allergic to macrolides)

Child: 24mg/kg/dose, twice daily, for 14 days

Adult: 960 mg (two tablets), twice daily, for 14 days

Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml or co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid or 480 mg tablets. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

Pneumonia – adult

Management

Antibiotic treatment is appropriate for all adults with suspected pneumonia.

Adults with pneumonia may present with symptoms and signs specific to the chest, or less specific respiratory and systemic symptoms, e.g. confusion (particularly in elderly people). Consider referral to hospital for patients with one or more of the following features: co-morbidities, altered mental state, respiratory rate > 30/min, pulse rate > 125/min, O2 saturation ≤ 92%, BP systolic < 90 mm Hg or diastolic < 60 mm Hg, age > 65 years, lack of reliable observation at home.

Chest x-ray is not routinely recommended in a community setting. It may be appropriate when the diagnosis is unclear, there is dullness to percussion or other signs of an effusion or collapse, or when the likelihood of malignancy is increased, such as in a smoker aged over 50 years.

Common pathogens

Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Legionella pneumophila, Staphylococcus aureus, respiratory viruses

N.B. Patients can generally be adequately treated with an antibiotic that covers S. pneumoniae.

Antibiotic treatment - Suspected or confirmed pneumonia

First choice

Amoxicillin

Adult: 500 mg - 1 g, three times daily, for five to seven days

If atypical organisms are suspected, e.g. M. pneumoniae, C. pneumoniae or L. pneumophila, or if the patient has not improved after 48 hours, add either:


Roxithromycin 300 mg, once daily, for seven days; or


Doxycycline 200 mg, twice daily, on day one, followed by 100 mg, twice daily, from days two to seven

Alternatives

Monotherapy with roxithromycin or doxycycline is acceptable for people with a history of penicillin allergy.

N.B. Ciprofloxacin should not be used as it does not reliably treat infections due to S. pneumoniae.

Pneumonia – child

Management

Antibiotic treatment is appropriate for all children with suspected pneumonia.

Children with pneumonia may present with a range of respiratory symptoms and signs; fever, tachycardia and increased respiratory effort are more common, auscultatory signs are less common. Consider referral to hospital for a child with any of the following features: age < 6 months, drinking less than half their normal amount, oxygen saturation ≤ 92% on air, increased respiratory effort, temperature < 35°C or > 40°C, decreased breath sounds or dullness to percussion, lack of reliable observation at home.

In addition, if there is no response to treatment in 24 - 48 hours, review diagnosis and consider referral to hospital.

Chest x-ray is not routinely recommended in a community setting. It may be appropriate when the diagnosis is unclear, there is dullness to percussion or other signs of an effusion or collapse or the history is suggestive of foreign body aspiration.

Common pathogens

Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Staphylococcus aureus, respiratory viruses

Antibiotic treatment - Suspected or confirmed pneumonia

First choice

Amoxicillin

Child: 25 - 30 mg/kg/dose, three times daily, for five to seven days (maximum 500 mg/dose age three months to five years, 1000 mg/ dose age > five years)

Alternatives

Erythromycin

Child: 10 – 12.5 mg/kg/dose, four times daily, for seven days

N.B. Can be first-line in school-aged children where the likelihood of atypical pathogens is higher.


Roxithromycin*

Child < 40 kg: 2.5 – 4 mg/kg/dose (maximum 150 mg), twice daily, for seven to ten days

Child > 40 kg: 150 mg, twice daily, for seven to ten days

*Roxithromycin is now also available in a 50 mg dispersable tablet for children < 12 years.

Ear, nose and throat

Otitis externa - acute

Management

Antibiotic treatment (topical) should only be considered if secondary infection is present.

First-line management is gentle cleansing of the external ear canal, e.g. with suction, a wick or probe. If signs of infection persist after thorough cleansing, a solution containing an anti-infective and a corticosteroid may be considered. Underlying chronic otitis media should be excluded before treatment. Most topical antibacterials are contraindicated in the presence of a perforated drum or grommets; they may, however, be used with caution if cleansing of the ear canal alone has been unsuccessful in resolving symptoms.

Patients with acute infection should be advised to avoid immersing their ears while swimming or to wear a protective cap.

N.B. People with diabetes or who are immunocompromised are at risk of necrotizing or malignant otitis externa.

Common pathogens

Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, polymicrobial infections

Antibiotic treatment - Otitis externa with secondary infection

First choice

Flumetasone + clioquinol (Locorten Vioform)

Adult and child > 2 years: 2 to 3 drops, twice daily, for 7 days

OR


Dexamethasone + framycetin + gramicidin (Sofradex)

Adult and child: 2 to 3 drops, three to four times daily, for seven days

N.B. Avoid using drops for longer than one week as this may result in fungal infection which can be difficult to treat

Alternatives

Acetic acid 2% (Vosol)* may be sufficient in mild cases.

* Currently subsidised brand


Triamcinolone + neomycin + gramicidin + nystatin (Kenacomb) if fungal infection is suspected


Ciprofloxacin + hydrocortisone (Ciproxin HC) if Pseudomonas suspected


Framycetin (Soframycin) if a steroid is not required as part of the preparation.

Otitis media - acute

Management

Antibiotic treatment is usually unnecessary as most infections are self-limiting.

Consider antibiotics for children at high risk, e.g. with systemic symptoms, aged < 6 months, aged < 2 years with severe or bilateral infection, with perforation and/or otorrhoea or if there has been no improvement within 48 hours. Also consider antibiotics in children with recurrent infections, i.e. three or more episodes of otitis media within six months or four or more within 12 months.

Otherwise treat symptomatically, e.g. paracetamol, and arrange follow up or give a “back pocket” prescription to be dispensed if no improvement in next 24 – 48 hours.

Otitis media with effusion - antibiotics provide little or no long-term benefit in children without acute symptoms; watchful waiting is recommended. Consider referral to otorhinolaryngology (ENT) if recurrent acute otitis media or persistent bilateral middle ear effusions for more than three months.

Common pathogens

Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis

Antibiotic treatment - Otitis media in child with risk factors or recurrent infection

First choice

Amoxicillin

Child: 15 mg/kg/dose, three times daily, for five days.

N.B. Treat for seven to ten days if aged < 2 years, underlying medical condition, bilateral otitis media or perforated ear drum

For severe or recurrent infection use 30 mg/kg/dose, three times daily, for five to seven days (maximum 500 mg/dose age three months to five years, 1000 mg/dose age > 5 years).

Alternatives

Trimethoprim + sulfamethoxazole*

Child > 6 weeks: 24 mg/kg/dose, twice daily, for five to seven days

* Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

Pharyngitis

Management

Antibiotic treatment is recommended for people at high risk of rheumatic fever.

Pharyngitis is of viral origin in approximately half of cases, and usually self-limiting, therefore antibiotic treatment is unnecessary in most cases. The exception to this is treating Group A Streptococcus pyogenes pharyngitis in high risk people to prevent rheumatic fever.

Those at high risk for rheumatic fever are defined as individuals who have a personal, family or household history of rheumatic fever, or who have two or more of the following criteria: Māori or Pacific ethnicity, age 3-35 years or living in crowded circumstances or in lower socioeconomic areas.

Refer to the New Zealand Heart Foundation Guidelines for further guidance.

Common pathogens

Respiratory viruses, Streptococcus pyogenes

Antibiotic treatment - Group A streptococcal pharyngitis in patients at high risk of rheumatic fever

First choice

Phenoxymethylpenicillin (Penicillin V)

Child: < 20 kg: 250 mg, two or three times daily, for ten days

Child ≥ 20 kg and Adults: 500 mg, two or three times daily, for ten days

OR


Amoxicillin

Child < 30 kg: 750 mg or 50 mg/kg (maximum 1000 mg/day), once daily, for ten days OR 25 mg/kg/dose (maximum 1000 mg/day), twice daily, for ten days

Child ≥ 30 kg and Adults: 1000 mg, once daily, for ten days OR 25 mg/kg/dose (maximum 1000 mg/day), twice daily, for ten days

OR


IM benzathine penicillin (stat)

Child < 30 kg: 450 mg (600 000 U)

Child ≥ 30 kg and Adults: 900 mg (1 200 000 U)

Alternatives

Erythromycin

Child: 40 mg/kg/day divided in 2-3 doses for ten days (usual maximum 1.6 g/day)

Adult: 400 mg, twice daily, for ten days


Roxithromycin*

Child: < 40 kg: 2.5 mg/kg/dose, twice daily, for ten days

Child: > 40 kg: 150 mg, twice daily, for ten days

Adult: 300 mg, once daily or 150 mg, twice daily, for ten days

*Roxithromycin is now also available in a 50 mg dispersable tablet for children < 12 years.

Sinusitis - acute

Management

Antibiotic treatment is not required in the majority of cases.

More than 90% of patients with sinusitis will not have a bacterial infection. Even in the small minority that do, symptoms are self-limiting and antibiotics only offer a marginal benefit.

Antibiotics may be considered for patients with symptoms that persist for more than ten days, onset of severe symptoms or fever (>39 °C) and purulent nasal discharge or facial pain lasting for at least three consecutive days, or onset of worsening symptoms after initial improvement.

Common pathogens

Respiratory viruses, Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, anaerobic bacteria

Antibiotic treatment - Persistent or severe sinusitis

First choice

Amoxicillin

Child: 25-30mg/kg/dose, three times daily, for seven days (maximum 500 mg/dose age three months to five years, 1000 mg/dose age > 5 years)

Adult: 500 - 1000 mg, three times daily for seven days

Alternatives

Doxycycline

Adult and child > 12 years: 200 mg on day one, followed by 100 mg, once daily, on days two to seven


Amoxicillin clavulanate* (if symptoms persist despite a treatment course of amoxicillin)

Child: 15 – 30 mg/kg/dose, three times daily, for seven days (maximum 500 mg/dose)

Adult: 625 mg, three times daily, for seven days

*Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Eyes

Conjunctivitis

Management

Antibiotic treatment is only required for patients with severe symptoms indicative of bacterial infection.

Conjunctivitis can be viral, bacterial or allergic. Bacterial conjunctivitis is usually associated with purulent discharge. Symptoms are self-limiting and the majority of people improve without treatment, in two to five days. Conjunctivitis due to adenovirus and enterovirus is also self limiting. Patients with suspected HSV conjunctivitis require evaluation by an ophthalmologist.

In newborn infants, consider Chlamydia trachomatis or Neisseria gonorrhoeae, in which case, do not use topical treatment. Collect appropriate eye swabs and refer to a paediatrician or ophthalmologist.

Patients with conjunctivitis can be advised to clean away secretions from the eyelids and eyelashes using cotton wool soaked in water. Advise hand washing after touching the eyes and avoid sharing pillows, facecloths and towels. Do not wear contact lenses. Artificial tear drops can be used to relieve discomfort.

Common pathogens

Viruses including HSV, Streptococcus pneumoniae, Haemophilus influenzae, Staphylococcus aureus. Less commonly: Chlamydia trachomatis or Neisseria gonorrhoeae

Antibiotic treatment - Severe bacterial conjunctivitis

First choice

Chloramphenicol 0.5% eye drops

Adult and child > 2 years: 1 – 2 drops, every 2-6 hours* until 48 hours after symptoms have cleared (or five days, whichever is shorter). Chloramphenicol 1% eye ointment may also be used at night in patients with severe infection or as an alternative to eye drops.

* Frequency of administration can be reduced after two to three days

Alternatives

Framycetin eye/ear drops (Soframycin)

Adult and child: 2 drops every 1-2 hours reducing to 2-3 drops, three times daily, until 48 hours after symptoms have cleared.


Fusidic acid eye gel 1%

Adult and child: 1 drop, twice daily until 48 hours after symptoms have cleared.

CNS

Meningitis and meningococcal septicaemia

Management

Antibiotic treatment should be given to all patients with suspected meningitis or meningococcal septicaemia, while awaiting transport to hospital (if this does not delay transfer).

Immediately refer all people with suspected meningitis or meningococcal septicaemia to hospital. Record observations, including neurological assessment, at least every 15 minutes while awaiting transfer. The first stage of meningococcal disease is associated with non-specific influenza-like symptoms and signs. Specific signs and symptoms of bacterial meningitis include: photophobia, severe headache, neck stiffness and focal neurologic deficit. Meningococcal septicaemia may be indicated by features such as non-blanching rash, unusual or mottled skin colour and rapidly deteriorating condition. Most patients will not display specific signs within the first four to six hours of illness (up to eight hours for adolescents) and infants may not display typical signs at all.

Meningococcal disease is notifiable on suspicion.

Common pathogens

Neisseria meningitidis, Streptococcus pneumoniae. Viral: enteroviruses, Herpes simplex virus, Varicella zoster virus and other viruses

Rare: Listeria monocytogenes, Haemophilus influenzae

Infants: Group B Streptococcus, L. monocytogenes, E.coli

Antibiotic treatment - Suspected meningitis or meningococcal septicaemia

First choice

Benzylpenicillin (penicillin G)

Child < 1 year: 300 mg IV or IM

Child 1 - 9 years: 600 mg IV or IM

Child > 10 years and Adult: 1.2 g IV or IM

Alternatives

Ceftriaxone

Child and Adult: 50 – 100 mg/kg (up to 2 g) IV or IM

N.B. Almost any parenterally administered antibiotic in an appropriate dose will inhibit the growth of meningococci, so if benzylpenicillin or ceftriaxone are not available, give any other penicillin or cephalosporin antibiotic.

Skin

Bites – human and animal

Management

Antibiotic treatment is recommended for all patients with infected bites or as prophylactic treatment, depending on the nature of the bite.

Prophylactic antibiotic treatment is recommended for human, dog or cat bites, severe or deep bites, bites on the hand, foot, face, tendon or ligament, in immunocompromised people and people presenting with an untreated bite, more than eight hours later.

Clean and debride the wound thoroughly and assess the need for tetanus immunisation.

Refer to hospital if there is bone or joint involvement.

Common pathogens

Polymicrobial infection, Pasteurella multocida, Capnocytophaga canimorsus (cat and dog bites), Eikenella corrodens (fist injury), Staphylococcus aureus, streptococci and anaerobes

Antibiotic treatment - Infected bite or prophylaxis if risk factors

First choice

Amoxicillin clavulanate*

Child: 15 - 30 mg/kg/dose (maximum 500 mg/dose), three times daily, for seven days

Adult: 625 mg, three times daily, for seven days

*Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Alternatives

Child > 12 years and Adult: Metronidazole 400 mg, three times daily, plus doxycycline 200 mg on day one, followed by 100 mg, once daily, on days two to seven.


Child < 12 years: Metronidazole 7.5 mg/kg/dose (maximum 400 mg), three times daily plus trimethoprim + sulphamethoxazole* 24 mg/kg/dose, twice daily, for seven days (maximum 20 mL/dose).

* Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

Boils (furuncles)

Management

Antibiotic treatment is not usually required. Most lesions should be treated with incision and drainage alone. A topical antiseptic may be useful.

Antibiotics may be considered if there is fever, spreading cellulitis or co-morbidity, e.g. diabetes, or if the lesion is in a site associated with complications, e.g. the face.

Common pathogens

Staphylococcus aureus

Consider MRSA if there is a lack of response to flucloxacillin, another penicillin or cephalosporin.

Antibiotic treatment - Boils (with complications)

First choice

Flucloxacillin

Child: 12.5-25 mg/kg/dose, three to four times daily, for five days

Adult: 500 mg, four times daily, for five days

Alternatives

Erythromycin (if allergy to flucloxacillin or MRSA present*)

Child aged < 12 years: 20 mg/kg/dose, twice daily, or 10 mg/kg/ dose, four times daily, for five days (maximum 1 g/day)

Adult: 800 mg, twice daily, or 400 mg, four times daily, for five days

*Based on MRSA susceptibilities


Trimethoprim + sulphamethoxazole (if allergy to flucloxacillin or MRSA present*)

Child > 6 weeks: 24 mg/kg/dose, twice daily, for five to seven days (maximum 960 mg/dose)

Child > 12 years and Adult: 960 mg (two tablets), twice daily, for five to seven days

Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml or co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid or 480 mg tablets. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

* Based on MRSA susceptibilities


Cefalexin (if flucloxacillin not tolerated)

Child: 12.5 – 25 mg/kg/dose, twice daily, for five days

Adult: 500 mg, four times daily, for five days

Cellulitis

Management

Antibiotic treatment is required for all patients with cellulitis. Oral antibiotic treatment is appropriate for those with mild to moderate cellulitis; intravenous treatment is usually required for patients with severe cellulitis or those not responding to oral treatment.

Keep affected area elevated (if applicable) for comfort and to relieve oedema. Assess response to treatment in two days. Discuss referral to hospital for consideration of IV antibiotics if cellulitis is extensive, not responding to oral antibiotics, systemic symptoms are present (e.g. fever, nausea, vomiting) and in young infants.

For periorbital or facial cellulitis, in all but very mild cases refer to hospital for consideration of IV antibiotics.

Common pathogens

Streptococcus pyogenes, Staphylococcus aureus, Group C or Group G streptococci

Antibiotic treatment - Mild to moderate cellulitis

First choice

Flucloxacillin

Child: 12.5 – 25 mg/kg/dose, four times daily, for five days

Adult: 500 mg, four times daily, for five days

Alternatives

Erythromycin (if allergy to flucloxacillin or MRSA present*)

Child aged < 12 years: 20 mg/kg/dose, twice daily, or 10 mg/kg/dose, four times daily, for five days (maximum 1 g/day)

Adult: 800 mg, twice daily, or 400 mg, four times daily, for five days

*Based on MRSA susceptibilities


Trimethoprim + sulphamethoxazole (if allergy to flucloxacillin or MRSA present*)

Child > 6 weeks: 24 mg/kg/dose, twice daily, for five to seven days (maximum 960 mg/dose)

Child > 12 years and Adult: 960 mg (two tablets), twice daily, for five to seven days

Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml or co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid or 480 mg tablets. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

* Based on MRSA susceptibilities


Cefalexin (if flucloxacillin not tolerated)

Child: 12.5 mg/kg/dose, four times daily, for five days (maximum 500 mg/dose)

Adult: 500 mg, four times daily, for five days

Diabetic foot infections

Management

Antibiotic treatment is required if there are signs of infection in the wound. It is recommended to take a wound swab for microbiological analysis.

The threshold for suspecting infection and testing a wound should be lower in people with diabetes and other conditions where perfusion and immune response are diminished, as classical clinical signs of infection are not always present.

Referral for further assessment should be considered if infection is suspected to involve the bones of the feet, if there is no sign of healing after four weeks of treatment, or if other complications develop.

Antibiotic treatment is not recommended for prevention of diabetic foot infections.

Common pathogens

Early infection is usually due to Staphylococcus aureus and/or streptococci. Later infection may be polymicrobial with a mixture of Gram-positive cocci, Gram-negative bacilli and anaerobes.

Antibiotic treatment - Infected foot wound in adult with diabetes

First choice

Amoxicillin clavulanate*

Adult: 625 mg, three times daily, for five to seven days

* Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Alternatives

Cefalexin 500 mg, four times daily, plus Metronidazole 400 mg, two to three times daily, for five to seven days

OR (for patients with penicillin hypersensitivity)

Trimethoprim + sulphamethoxazole* 960 mg (two tablets), twice daily, plus clindamycin 300 mg, three times daily, for five to seven days

* Formerly referred to as co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 480 mg tablets.

Requires specialist endorsement for > 4 capsules

Impetigo

Management

Antibiotic treatment is not usually required initially; good skin hygiene is the first-line management. There is a limited role for topical antibiotic treatment; only for localised infection and second-line to topical antiseptics. Oral antibiotic treatment is recommended for more extensive, widespread infection, or if systemic symptoms are present.

Initial management involves the simple measures of “clean, cut (nails) and cover”. Use moist soaks to gently remove crusts from lesions, keep affected areas covered and exclude the child from school or preschool until 24 hours after treatment has been initiated. Assess and treat other infected household members.

Topical treatment is only appropriate for areas of localised impetigo (usually ≤ 3 lesions). C urrent expert opinion favours the use of antiseptic cream, such as hydrogen peroxide or povidone-iodine, as first choice topical treatment, due to high rates of fusidic acid resistance in S. aureus in New Zealand.

Recurrent impetigo may be the result of chronic nasal carriage of S. aureus (patient or household contact), or re-infection from fomite colonisation, e.g. clothing, linen, and may require decolonization.

Common pathogens

Streptococcus pyogenes, Staphylococcus aureus

Antibiotic treatment - Impetigo (non-antibiotic + antibiotic treatment)

First choice

Hydrogen peroxide 1% cream

Apply 2-3 times daily, for five days

OR


Povidone-iodine 10% ointment

Apply 2-3 times daily, for five days

Flucloxacillin

Child: 12.5 - 25 mg/kg/dose, four times daily, for five days (maximum 500 mg/dose)

Adult: 500 mg, four times daily, for five days

Alternatives

Fusidic acid 2% cream or ointment

Apply twice daily, for five days

N.B. Use topical Fusidic acid as second line treatment after topical antiseptics and only if the infection is localized. If topical treatment fails, use oral treatment as above.

Trimethoprim + sulphamethoxazole* (if complicated infection, MRSA present† or allergy to flucloxacillin)

Child > 6 weeks:24 mg/kg/dose, twice daily, for five days (maximum 20 mL/dose)

Child > 12 years and Adult: 960 mg (two tablets), twice daily, for five days

* Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml or co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid or 480 mg tablets. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.


Erythromycin (if allergy to flucloxacillin or MRSA present)

Child aged < 12 years: 20 mg/kg/dose, twice daily, or 10 mg/kg/ dose, four times daily, for five days (maximum 1.6 g/day)

Adult: 800 mg, twice daily, or 400 mg, four times daily, for five days

Based on MRSA susceptibilities


Cefalexin (if flucloxacillin not tolerated)

Child: 12–25 mg/kg/dose, twice daily, for five days

Adult: 500 mg, four times daily or 1 g, twice daily, for five days

Mastitis

Management

Antibiotic treatment is required for severe, worsening or persistent symptoms.

Conservative management to alleviate symptoms (e.g. gentle massage, warm compress) and ongoing breast emptying may be all that is required for treatment. If there is no improvement within 12-24 hours or symptoms are severe or worsening, antibiotics should be started. Breast feeding (or expressing) from both breasts should be continued; this is an important component of treatment and poses no risk to the infant.

Common pathogens

Staphylococcus aureus in lactating women, S. aureus and anaerobes in non-lactating females, or in males

Antibiotic treatment - Severe or non-resolving mastitis

First choice

Flucloxacillin

Adult: 500 mg, four times daily, for 5-7 days

Alternatives

Erythromycin

Adult: 400 mg, four times daily, for 5-7 days


Cefalexin

Adult: 500 mg, four times daily, for 5-7 days


N.B. Treat mastitis in males or non-lactating females with Amoxicillin clavulanate* 625 mg, three times daily, for seven days

* Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Gastrointestinal

Campylobacter enterocolitis

Management

Antibiotic treatment is recommended for people with symptoms that are severe (e.g. high fever, bloody diarrhoea) or prolonged (> 7 days).

Antibiotics may also be considered for people at high risk of complications or those who are at higher risk of transmitting infection to vulnerable people (although this is rare). This includes pregnant women, people who are immunocompromised and their carers, food handlers and childcare workers.

Most people will recover with symptomatic treatment only, including rehydration. Antibiotics reduce the average duration of symptoms by less than two days but eradicate stool carriage. People can remain infectious to others for up to several weeks after onset of symptoms. However, with or without antibiotic treatment, spread from person to person is very rare.

Campylobacter enterocolitis is a notifiable disease.

Common pathogens

Campylobacter jejuni

Antibiotic treatment - Severe or prolonged campylobacter enterocolitis or high risk

First choice

Erythromycin

Child: 10 mg/kg/dose, four times daily, for five days

Adult: 400 mg, four times daily, for five days

Alternatives

Ciprofloxacin

Adult: 500 mg, twice daily, for five days (not recommended for children)

Clostridium difficile colitis

Management

Antibiotic treatment is recommended for adults who have tested positive for C. difficile toxin, and have diarrhoea or other symptoms consistent with colitis.

C. difficile colitis occurs due to overgrowth of toxin-producing C. difficile in the colon. A common cause is the use of broad spectrum antibiotic treatment. Discontinuing such antibiotic treatment, if and when possible, may lead to clinical resolution of symptoms.

Antidiarrhoeals, e.g. loperamide, should be avoided as the toxin may be retained and worsen colitis. Consider referral to hospital if there is evidence of worsening colitis. Relapse may occur after treatment.

In children, detection of C. difficile commonly represents colonisation rather than pathological infection, so testing is discouraged, and antibiotic treatment is not generally required in the community setting.

Common pathogens

Clostridium difficile

Antibiotic treatment - Confirmed C. difficile (adults)

First choice

Metronidazole

Adult: 400 mg, three times daily, for 10 days

Alternatives

Vancomycin

If patient has not responded to two courses of metronidazole; discuss with an infectious diseases physician or clinical microbiologist. Oral vancomycin (using the injection product) may be required.

Giardiasis

Management

Antibiotic treatment is recommended for people who have tested positive for giardia, and for symptomatic contacts.

Secondary lactose intolerance often occurs after giardiasis; patients with ongoing symptoms after treatment can consider temporarily avoiding lactose-containing foods (e.g. for one month).

People can remain infectious to others for up to several months after onset of symptoms.

Giardiasis is a notifiable disease.

Common pathogens

Giardia lamblia

Antibiotic treatment - Confirmed giardiasis or symptomatic contact

First choice

Ornidazole

Child < 35 kg: 125 mg/3 kg/dose,* once daily, for one to two days

Adult and child > 35 kg: 1.5 g, once daily, for one to two days

* N.B. dose is per 3 kg bodyweight; ornidazole is only available in tablet form, tablets may be crushed, child dosing equates to one quarter of a tablet per 3 kg.

OR


Metronidazole

Child: 30 mg/kg/dose, once daily, for three days (maximum 2 g/dose)

Adult: 2 g, once daily, for three days

Alternatives

For treatment failure with ornidazole:

Exclude re-infection from asymptomatic family contacts, e.g. children

Metronidazole

Child: 10 mg/kg/dose, three times daily, for seven days, (maximum 400 mg/dose)

Adult: 400 mg, three times daily, for seven days

N.B. Nitazoxanide (hospital treatment) may be considered for recurrent treatment failures.

Salmonella enterocolitis

Management

Antibiotic treatment is usually unnecessary and may prolong excretion. Antibiotic treatment is, however, recommended for adults with severe disease, those who are immunocompromised and those with prosthetic vascular grafts.

Discuss appropriate treatment for infants with a paediatrician; those aged < 3 months will require investigation and antibiotic management; those aged > 3-12 months may not, depending on clinical state.

People typically remain infectious to others for several days to weeks after onset of symptoms; children may remain infectious for up to one year. However, with or without antibiotic treatment, spread to others is very rare.

Common pathogens

Salmonella enteritidis, Salmonella typhimurium

Antibiotic treatment - Severe salmonella enterocolitis or risk factors

First choice

Ciprofloxacin

Adult: 500 mg, twice daily, for three days

Alternatives

Trimethoprim + sulfamethoxazole*

Adult: 960 mg (two tablets), twice daily, for three days

* Formerly referred to as co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 480 mg tablets.

Genito-urinary

Bacterial vaginosis

Management

Antibiotic treatment is recommended for women who are symptomatic, pregnant or if an invasive procedure is planned, e.g. insertion of an IUD or termination of pregnancy.

Approximately half of women found to have bacterial vaginosis are asymptomatic; antibiotic treatment is not necessary in these cases if there are no other risk factors. Treatment of male sexual contacts is not usually necessary.

Common pathogens

Gardnerella vaginalis, Bacteroides, Peptostreptococci, Mobilunculus and others

Antibiotic treatment - Symptomatic bacterial vaginosis or risk factors

First choice

Metronidazole

Adult: 400 mg, twice daily, for seven days, or 2 g, stat, if adherence to treatment is a concern (although this dose is associated with a higher relapse rate)

Alternatives

Ornidazole

500 mg, twice daily, for five days or 1.5 g, stat.

Ornidazole is not recommended in women who are pregnant as no study data is available.

Chlamydia

Management

Antibiotic treatment is indicated for people with confirmed chlamydia and their sexual partners or if there is a high suspicion of chlamydia (symptoms and/or signs).

In suspected cases, empiric treatment should be commenced while awaiting laboratory results.

Advise avoidance of unprotected sexual intercourse for seven days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re-infection. A test of cure should be done five weeks after initiation of treatment in pregnant women, if a non-standard treatment has been used, e.g. amoxicillin, or if symptoms do not resolve. Repeat STI screen in three months.

Common pathogens

Chlamydia trachomatis

Antibiotic treatment - Confirmed or suspected chlamydia

First choice

Azithromycin

Adult: 1 g, stat

OR


Doxycycline (if rectal infection, highly symptomatic or alternative required)

Adult: 100 mg, twice daily, for seven days. Do not use in women who are pregnant or breastfeeding.

Alternatives

Amoxicillin (alternative for pregnant women if azithromycin contraindicated)

500 mg, three times daily, for seven days

Epididiymo-orchitis

Management

Antibiotic treatment is required for all suspected cases of epididymo-orchitis.

Epididymo-orchitis may occur due to a variety of pathogens; STI pathogens are more likely in males aged < 35 years, with a history of more than one sexual partner in the past 12 months, and urethral discharge. Urinary or enteric pathogens account for other cases.

Test for chlamydia, gonorrhoea and urinary tract infection; empirical treatment should be given while awaiting results.

If symptoms are initially severe or signs and symptoms do not resolve (or worsen) after 24 to 48 hours, refer to hospital.

Advise avoidance of unprotected sexual intercourse for seven days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re- infection.

Common pathogens

Majority due to Chlamydia trachomatis or Neisseria gonorrhoeae. Also E. coli, Bacteroides species, Gardnerella vaginalis, Mycoplasma hominis, Ureaplasma urealyticum, Trichomonas vaginalis, Streptococcus agalactiae and others

Antibiotic treatment - Suspected epididymo-orchitis

First choice

Ceftriaxone

Adult: 500 mg IM, stat (make up with 2 mL of lignocaine 1% or according to data sheet)

AND

Doxycycline

Adult: 100 mg, twice daily, for 14 days

Ciprofloxacin

Adult: 500 mg, twice daily, for 10 days

Alternatives

Amoxicillin clavulanate*

625 mg, three times daily, for 10 days (if UTI pathogens suspected and contraindications to quinolones)

* Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Gonorrhoea

Management

Antibiotic treatment is indicated for people with confirmed gonorrhoea and their sexual partners or if there is a high suspicion of gonorrhoea (symptoms and/or signs).

In suspected cases, empiric treatment should be commenced while awaiting laboratory results.

Advise avoidance of unprotected sexual intercourse for seven days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re- infection. A test of cure should be done five weeks after initiation of treatment in pregnant women, or if a non-standard treatment has been used or if symptoms do not resolve.

Repeat STI screen in three months. As co-infection with chlamydia is very common, azithromycin is also routinely given.

Common pathogens

Neisseria gonorrhoeae

Antibiotic treatment - Confirmed or suspected gonorrhoea

First choice

Ceftriaxone

Adult: 500 mg IM, stat (make up with 2 mL of 1% lignocaine or according to data sheet)

AND

Azithromycin

Adult: 1 g, stat (including in women who are pregnant or breastfeeding)

Alternatives

If isolate is ciprofloxacin susceptible and an alternative is required:

Ciprofloxacin 500 mg, stat + Azithromycin 1 g, stat

Pelvic inflammatory disease

Management

Antibiotic treatment is required for females who are symptomatic.

Pelvic inflammatory disease (PID) is usually caused by a STI, particularly in women aged < 25 years, those who have had recent change of sexual partner or those with a previous history of gonorrhoea or chlamydia. Empiric treatment should be started immediately on the basis of symptoms. Treatment should cover infection with gonorrhoea, chlamydia and anaerobes.

Women with severe symptoms (e.g. fever, vomiting, acute abdominal pain) and pregnant women require referral for specialist assessment. Hospital admission may be required for IV antibiotics.

Advise abstinence from sexual intercourse until abdominal pain has settled and avoidance of unprotected sexual intercourse for 14 days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re-infection.

Common pathogens

Chlamydia trachomatis, Neisseria gonorrhoeae and others

Antibiotic treatment - Symptomatic pelvic inflammatory disease

First choice

Ceftriaxone

Adult: 500 mg IM, stat (make up with 2 mL of 1% lignocaine or according to data sheet)

AND

Doxycycline

Adult: 100 mg, twice daily, for 14 days

AND

Metronidazole

Adult: 400 mg, twice daily, for 14 days (metronidazole may be discontinued if not tolerated)

Alternatives

Ceftriaxone 500 mg IM, stat + Azithromycin 1 g on day one and day eight is an alternative if compliance is likely to be poor


Ornidazole

500 mg, twice daily, for fourteen days may be considered as an alternative to metronidazole, if not tolerated

Trichomoniasis

Management

Antibiotic treatment is indicated for people with confirmed trichomoniasis and their sexual partners or if there is a high suspicion of trichomoniasis (symptoms and/or signs).

Empiric treatment may be commenced while awaiting laboratory results. Due to low sensitivity, culture of urethral swabs is rarely positive in males, even if infection is present.

Advise avoidance of unprotected sexual intercourse for seven days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re-infection.

A test of cure is not usually required unless there is a risk of reexposure.

Common pathogens

Trichomonas vaginalis

Antibiotic treatment - Confirmed or suspected trichomoniasis

First choice

Metronidazole

Adult: 2 g, stat

Alternatives

Metronidazole

400 mg, twice daily, for seven days may be used for those intolerant of the stat dose.


Ornidazole

1.5 g, stat or 500 mg, twice daily, for five days may be used instead of metronidazole, but is not recommended in women who are pregnant as no study data is available.

Urethritis – acute non-specific, male

Management

Antibiotic treatment is required for males who are symptomatic.

Non-specific urethritis is a diagnosis of exclusion. A urethral swab and first void urine sample should be taken to exclude gonorrhoea and chlamydia (or use combination testing if available). Treat sexual contacts if STI is present. Advise avoidance of unprotected sexual intercourse for seven days after treatment has been initiated, and for at least seven days after any sexual contacts have been treated, to avoid re-infection.

Patients with symptoms persisting for more than two weeks, or with recurrence of symptoms, should be referred to a sexual health clinic or urologist.

Common pathogens

Urethritis not attributable to Neisseria gonorrhoeae or Chlamydia trachomatis is termed non-specific urethritis and there may be a number of organisms responsible, e.g. Ureaplasma urealyticum, Mycoplasma genitalium, Trichomonas vaginalis

Antibiotic treatment - Symptomatic acute non-specific urethritis

First choice

Azithromycin

Adult: 1 g, stat

OR


Doxycycline

Adult: 100 mg, twice daily, for seven days


If purulent discharge, treat as for gonorrhoea, i.e. Ceftriaxone 500 mg IM, stat + Azithromycin 1g, stat

Alternatives

Nil

Urinary Tract Infection – Cystitis: adult

Management

Antibiotic treatment is indicated for adults with symptoms and signs of cystitis (lower urinary tract infection).

Urine culture is not necessary to diagnose cystitis. Urine culture is most useful for confirming the presence of significant bacteriuria and reporting on bacterial susceptibility to antibiotics in infections that are considered to be complicated due to an abnormality of the urinary tract or an underlying condition or clinical circumstance; this includes:

  • Males
  • Pregnant women
  • People with diabetes or renal failure
  • People with a urinary catheter
  • People living in residential care facilities
  • People with persistent or recurrent cystitis (three or more infections in one year) or atypical symptoms

N.B. Urine culture is not recommended in asymptomatic people. However, if bacteriuria is incidentally found to be present, this only requires antibiotic treatment in pregnant women.

Also see Pyelonephritis

Common pathogens

Escherichia coli, Staphylococcus saprophyticus, Proteus spp., Klebsiella spp., Enterococcus spp.

Antibiotic treatment - Symptomatic cystitis (adult)

First choice

Nitrofurantoin

Adult: 50 mg, four times daily, for five days (avoid at 36+ weeks in pregnancy, and in patients with creatinine clearance < 60 mL/min)

OR


Trimethoprim

Adult: 300 mg, once daily, for three days (avoid during the first trimester of pregnancy)

N.B. Treat for seven days in pregnant women and in males

Alternatives

Norfloxacin (only for isolates resistant to first-line choices)

Adult: 400 mg, twice daily for three days (seven days for males) –avoid during pregnancy

N.B. If susceptibility testing indicates resistance to commonly available antibiotics, discuss treatment with a clinical microbiologist or infectious diseases specialist; alternative antimicrobials may be available in some DHBs

Urinary Tract Infection – Cystitis: child

Management

Antibiotic treatment (oral) is indicated for children aged over six months, without known renal tract abnormalities, and who do not have acute pyelonephritis. Refer children aged under six months, those with severe illness, or those with recurrent infection, to hospital for treatment.

All children with suspected urinary tract infection should have a urine sample for culture collected (clean catch, catheter, midstream urine) as it may be a marker for previously undetected renal malformations, particularly in younger children. In older children it can be a marker for bladder and/or bowel dysfunction.

For information on collecting a urine specimen in children, see: "Managing urinary tract infections in children", BPJ 44 (May, 2012).

Common pathogens

Escherichia coli, Proteus spp., Klebsiella spp., Enterococcus spp.

Antibiotic treatment - Mild cystitis (child)

First choice

Trimethoprim + sulfamethoxazole*

Child: 24 mg/kg/dose, twice daily, for three days (maximum 960 mg/dose)

* Formerly referred to as co-trimoxazole oral liquid 40+200 mg/5ml; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 240 mg/5 mL oral liquid. N.B. avoid in infants aged under six weeks, due to the risk of hyperbilirubinaemia.

Alternatives

Cefalexin

Child > 1 month: 12.5-25 mg/kg/dose, twice daily, for three days (maximum 1 g/dose)


Amoxicillin clavulanate*

Child: 15 mg/kg/dose, three times daily, for three days (maximum 625 mg/dose

*Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio

Urinary Tract Infection - Pyelonephritis

Management

OAntibiotic treatment (oral) is required for all patients with mild symptoms of pyelonephritis (upper urinary tract infection); patients with more severe symptoms (e.g. vomiting, dehydration, high fever), and all infants and children, require referral to hospital for treatment.

Urine culture is recommended for all patients with suspected pyelonephritis. Renal tract ultrasound may also be appropriate depending on the clinical situation.

Common pathogens

Escherichia coli, Proteus spp., Klebsiella spp., Enterococcus spp.

Antibiotic treatment - Mild pyelonephritis (adult)

First choice

Trimethoprim + sulfamethoxazole*

Adult: 960 mg (two tablets), twice daily, for 10 days

* Formerly referred to as co-trimoxazole tablets 80+400 mg; now expressed as the total dose of trimethoprim + sulfamethoxazole (ratio 1:5) - 480 mg tablets.

Alternatives

Amoxicillin clavulanate*

Adult: 625 mg, three times daily, for 10 days

* Expressed as a combination of amoxicillin and clavulanic acid 4:1 ratio


Ciprofloxacin (only for isolates resistant to other choices)

500 mg, twice daily, for seven days – but should be reserved for isolates resistant to initial empiric choices and avoided during pregnancy


N.B. Nitrofurantoin is not an appropriate choice for the treatment of pyelonephritis as it fails to achieve tissue penetration. Oral trimethoprim might be used in a hospital setting after IV treatment.

Acknowledgement

Thank you to the Paediatric Infectious Diseases Team (Drs Best, Lennon, Voss, Webb and Wilson), Starship Children’s Health, Dr Rosemary Ikram, Clinical Microbiologist, Christchurch, and Associate Professor Mark Thomas, Infectious Diseases Specialist, School of Medical Sciences, University of Auckland, for expert review and comment on this resource.


The following main resources were used in the development of this guide:

  1. bpacnz. Best Practice Journal. Available from: www.bpac.org.nz
  2. New Zealand Formulary and New Zealand Formulary for Children. Available from: www.nzformulary.org
  3. Starship Children’s Health. Clinical guidelines. Available from: www.adhb.govt.nz/starshipclinicalguidelines
  4. The National Heart Foundation of New Zealand. Guidelines for rheumatic fever. Available from: www.heartfoundation.org.nz
  5. The New Zealand Sexual Health Society (NZSHS). Best practice guidelines. Available from: www.nzshs.org/guidelines.html

The information in this publication is specifically designed to address conditions and requirements in New Zealand and no other country. BPAC NZ Limited assumes no responsibility for action or inaction by any other party based on the information found in this publication and readers are urged to seek appropriate professional advice before taking any steps in reliance on this information.

Published: 14 July 2017 | Updated:

Antibiotics Guide Menu
The Editor 14/07/2017 4:37:07 p.m.
The Editor 14/07/2017 2:48:01 p.m.

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