Community Acquired Pneumonia

Markers of severity in CAP

1. CURB-65 score :

C onfusion (new onset)

U rea >7mmol/L

R R≥30/min

B P - hypotension: sBP <90mmHg or dBP ≤60mmHg

Age ≥ 65 years

Clinical judgement is essential when deciding on the management of all patients with CAP. CURB-65 score should be used with caution in younger patients (<30 years) as it may underestimate severity in these patients.

2. Other indicators of severity include:

• SIRS criteria
• Multilobar infiltrates
• Thrombocytopenia platlets <100 x10 ⁹ /L
• Hypoxaemia, respiratory failure.
• High lactate

Choosing antibiotics

Consider:

• Severity assessment
• Risk of developing complications
• Local epidemiology (eg. influenza, COVID-19 rates)
• Parenteral antibiotic use in the last 90 days
• Hospitalization in the last 90 days
• Recent microbiology test results, including colonisation with MDROs.
• Drug contraindications and interactions.
• Giving oral antibiotics first line if the person can take oral medicines, and the severity of their condition does not require intravenous antibiotics. Review intravenous antibiotics by 48 hours and consider switching to oral antibiotics if possible

Comments

These guidelines are NOT aimed at:

(a) Patients with conditions such as cancer or immunosuppression including those admitted with pneumonia to specialist units such as oncology, haematology, palliative care, infectious disease units or AIDS units.

(b) Adults with non-pneumonic LRTIs, including acute bronchitis and exacerbations of COPD.

The most common pathogens in CAP are Streptococcus pneumoniae, Haemophilus influenzae. Also S. aureus, Legionella pneumophilia, Mycoplasma pneumoniae.

Investigations: Send blood cultures, sputum culture (requesting legionella culture), urine for pneumococcal antigen, (& legionella antigen in severe CAP and if epidemiological risk factors).

In all patients with severe CAP send urine for legionella antigen, and test for HIV infection.

Mild CAP (CURB-65=0-1)

Low Severity (CURB-65 = 0-1) <3% mortality

Antibiotic

First line : Amoxicillin 1g TDS PO

Penicillin allergy:

Doxycycline 200mg once daily loading dose on day 1 followed by 100mg once daily PO

OR

Clarithromycin 500mg BD PO (Caution as risk of QT prolongation; consider interaction with statins).

Comments

Duration: 5 days

Moderate CAP (CURB-65=2)

Moderate Severity (CURB-65 = 2) 3-15% mortality

Antibiotic

First line:

Amoxicillin 1g TDS PO or IV

+

Clarithromycin 500mg BD PO or IV (Excellent oral bioavailability). Caution as risk of QT prolongation; consider interaction with statins.

OR

Doxycycline 200mg loading dose on day 1 followed by 100mg once daily PO.

Switch IV to oral when clinically appropriate.

Penicillin allergy:

Doxycycline 200mg once daily loading dose on day 1 followed by 100mg once daily PO.

OR

Clarithromycin 500mg BD PO or IV (Excellent oral bioavailability, Caution as risk of QT prolongation; Consider interaction with statins).

Comments

Duration: 5 days.

Severe CAP (CURB-65=3-5)

High severity (CURB-65 = 3-5) >15% mortality.

Antibiotic

CURB-65=3-5 :

Co-amoxiclav 875/125mg TDS PO or 1.2g TDS IV

+

Clarithromycin 500mg BD PO or IV (Excellent oral bioavailability). Caution as risk of QT prolongation; consider interaction with statins.

(If legionella strongly suspected consider using * Levofloxacin instead, see below for more information).

Oral stepdown: Review microbiology test results and tailor therapy accordingly. Discuss with microbiology team if required. Switch IV to oral when clinically appropriate.

Penicillin allergy:

*Levofloxacin 500mg BD PO or IV (Excellent oral bioavailability).

If patient is colonised with or considered to be high risk for MRSA, consider adding Vancomycin or Teicoplanin to the above combinations while awaiting culture and screen results. (Please see Vancomycin / Teicoplanin dosing schedule).

* Please read the HPRA Drug Safety Alert issued in 2018 and the HPRA Drug Safety Newsletter issued in 2023 highlighting restrictions on use of fluoroquinolones (eg. ciprofloxacin, levofloxacin) due to the risk of disabling, long-lasting and potentially irreversible side effects (including tendon damage, QT prolongation, neuropathies and neuro psychiatric disorder). Use of fluoroquinolones in older patients, those with renal impairment, solid organ transplantation or on systemic corticosteroids increases the risk of tendon damage.

Comments

• Send blood cultures, sputum culture (requesting legionella culture), urine for pneumococcal and legionella antigen, and HIV test.
• Consider switch to PO antibiotics as soon as clinical improvement occurs and patient is apyrexial for 24 hours.
• Stop glycopeptide if no evidence of MRSA.
• Discuss antibiotic choice with microbiology or infectious diseases specialist if risk factors for multi-drug resistant pathogens, failure to respond to empirical treatment or concerns of complications such as lung abscess or empyema.
• Duration: 5 days. This may need to be extended according to clinical judgement.
• Offer annual influenza vaccine to patients prior to hospital discharge if inpatient during flu season and appropriate to do so. See National Immunisation Guidelines for more details.
• Check pneumococcal vaccine status and arrange vaccination if required.

References

NICE guideline Pneumonia (community-acquired): antimicrobial prescribing. 7 ^th July 2022

ATS/ IDSA Guidelines for the Diagnosis and Treatment of Adults with Community-acquired Pneumonia (2019)

CAP and COVID-19

General points

Inappropriate antibiotic use may reduce availability if used indiscriminately, and broad-spectrum antibiotics in particular may lead to Clostridioides difficile infection and antimicrobial resistance.

Send investigations: eg. Swab for SARS CoV2-RNA, blood and sputum cultures, pneumococcal +/- legionella urinary antigens, CXR, FBC.

Differentiating between COVID-19 pneumonia and bacterial pneumonia on clinical features alone can be difficult.

Note many patients with COVID-19 may have a high CRP which does not by itself indicate the presence of a bacterial infection.

As COVID -19 is a viral infection antibiotics are ineffective unless there is a bacterial co-infection which is thought to be uncommon (<10%). The risk of bacterial co-infection is likely increased in those requiring critical care and may present later in hospital as HAP or VAP.

The following features may indicate the presence of bacterial pneumonia:

• Characteristic symptoms such as purulent sputum or pleuritic chest pain,
• Localised chest findings on clinical exam
• Lobar consolidation on CXR
• Neutrophilia

For the use of anti-virals in the treatment of COVID-19, please see most recent HSE Clinical Guidance:

HSE Clinical Guidance on Paxlovid™ (nirmatrelvir/ritonavir) for use in the Treatment of COVID-19

Issued: July 2025

HSE Prescribing Protocol for Remdesivir use in the Treatment of COVID-19

Issued: December 2023

Antibiotics in CAP and suspected/proven COVID-19

The following guidance from the HSE may be of use when deciding when to start antibiotics in these patients:

1. No purulent sputum and no evidence of pneumonia:

• Do not prescribe antibiotics for the treatment of secondary bacterial pneumonia.

2. Purulent sputum AND one of bronchitis/pneumonia (CURB 0-2) OR if known underlying lung disease where patient has a history of secondary bacterial infection in winter months:

• First Line: Doxycycline 200mg on day 1 then 100mg once daily for 5 days in total.
• Alternative: Amoxicillin 500mg TDS PO for 5 days.

3. Severe CAP (CURB 3-5): See CAP guideline.

Review previous microbiology test results for history of respiratory tract colonisation or infection with Pseudomonas aeruginosa or MDROs such as MRSA.

In patients with immunosuppression or severe underlying lung disease use HAP (>5 days in hospital) guideline.

Review all antibiotics following SARS CoV-2 RNA test result and/or at 24-48 hours.

If following appropriate investigations there is no evidence of secondary bacterial infection, empirical antibiotics can be stopped.

References

1. Antimicrobial Stewardship and COVID-19. HPSC 24 ^th April 2020
2. Advice to antimicrobial management teams on antimicrobial prescribing in suspected lower respiratory tract infections in the context of the COVID-19 pandemic. Healthcare Improvement Scotland. SAPG 12 ^th May 2020.

3. COVID-19 rapid guideline: managing suspected or confirmed pneumonia in adults in the community. NICE guideline [NG165] Published date: 03 April 2020 Last updated: 23 April 2020.

General points

Risk factors: older age, smoking, chronic lung, cardiovascular or renal disease, immunocompromised.

When to suspect: Legionnaire's disease usually presents as community acquired pneumonia but infection can also be hospital-acquired. Infection is usually associated with exposure to a water source contaminated with L. pneumophilia such as spas, hot tubs etc. Illness can present with multisystem features including GI symptoms, neurological features such as confusion, and low serum sodium in addition to features of respiratory tract infection.

Investigations : Urine specimen for detection of Legionella antigen. Send serum for legionella antibody testing if high clinical suspicion and urinary antigen is not detected (Urine assay does not detect all Legionella serogroups).

Request legionella culture on respiratory specimens (sputum, tracheal aspirate or BAL).

Note: Legionellosis is a notifiable disease in Ireland.

There is no evidence of person-to-person spread of Legionella pneumophilia.

Antibiotics

* Levofloxacin 750mg once daily PO or IV (Excellent oral bioavailability).

Discuss with Microbiologist.

IV route to be used if oral absorption is unreliable.

Alternatives: Clarithromycin 500mg BD PO or IV if oral administration not possible OR Azithromycin 500mg once daily PO (Caution as risk of QT prolongation, consider interaction with statins).

* Please read the HPRA Drug Safety Alert issued in 2018 and the HPRA Drug Safety Newsletter issued in 2023 highlighting restrictions on use of fluoroquinolones (eg. ciprofloxacin, levofloxacin) due to the risk of disabling, long-lasting and potentially irreversible side effects (including tendon damage, QT prolongation, neuropathies and neuro psychiatric disorder). Use of fluoroquinolones in older patients, those with renal impairment, solid organ transplantation or on systemic corticosteroids increases the risk of tendon damage.

References

1. Uptodate.com Accessed 6th August 2025.
2. HPSC Legionnaires’ Disease https://www.hpsc.ie/a-z/respiratory/legionellosis/

Residential Care Facility Acquired Pneumonia

General Points

Nursing home-acquired pneumonia is defined as pneumonia occurring in a resident of a residential care facility or nursing home and more closely resembles CAP than HAP.

Piperacillin-Tazobactam is NOT first line empiric treatment for uncomplicated Pneumonia Acquired in Residential Care Facilities.

Refer to CAP guidelines for advice on treatment based on CURB-65 severity.

MRSA Colonisation

If patient is colonised with MRSA, add Vancomycin or Teicoplanin (See Vancomycin / Teicoplanin dosing schedule) and obtain cultures (blood culture/ sputum) to allow de-escalation/confirmation of need for continuation of therapy

P. aeruginosa Colonisation

If patient is colonised with P. aeruginosa, use anti-pseudomonal agent (Piperacillin-Tazobactam 4.5g QDS IV) and obtain cultures (blood culture/ sputum) to allow de-escalation/ confirmation of need for continuation of therapy

Patients at increased Risk

In patients at increased risk of infection with MRSA and/or P. aeruginosa ( recent hospitalization/ IV antibiotic exposure in the last 90 days ):

1) If severe CAP (CURB 3-5) then add coverage for MRSA +/- P. aeruginosa as above and obtain cultures to allow de-escalation/ confirmation of need for continuation of therapy.

2) If non-severe CAP (CURB 0-2) then obtain cultures for MRSA and P. aeruginosa but add coverage only if culture results are positive.

Comments

Discuss antibiotic choice with a Clinical Microbiology or Infectious Diseases Specialist if risk factors for multi-drug resistant pathogens, failure to respond to empirical treatment or concerns of complications such as lung abscess or empyema.

References

ATS/ IDSA Guidelines for the Diagnosis and Treatment of Adults with Community-acquired Pneumonia (2019)

Hospital-Acquired Pneumonia - within 5 days of admission

General Points

HAP within 5 days of admission AND

• No recent broad-spectrum antibiotics
• No relevant co-morbidity such as severe lung disease or immunosuppression
• No colonisation with MDRO

-For Ventilator-associated pneumonia see HAP >5 days post admission guideline.

-Check previous microbiology test results in particular for history of MDROs (MRSA, ESBL, and CPE).

-Send sputum or tracheal aspirate for culture.

-Send blood cultures if febrile or in sepsis.

-Consider Legionella. If suspected send urine for legionella antigen, sputum for Legionella culture and add clarithromycin empirically unless being treated with levofloxacin.  See section on Legionellosis.

Antibiotics

First line: Co-amoxiclav 875mg/125mg TDS PO or 1.2g TDS IV.

Penicillin allergy:

Non-IgE mediated /non-severe reaction :

Ceftriaxone 2g once daily IV

IgE-mediated / anaphylaxis / severe reaction :

* Levofloxacin 500mg PO or IV BD (excellent oral bioavailability)

Add Metronidazole 500mg TDS IV or 400mg TDS PO, ( excellent oral bioavailability), in aspiration pneumonia.

Note: treatment of aspiration pneumonia does not require addition of metronidazole to either piperacillin-tazobactam or co-amoxiclav as both provide sufficient anaerobic cover.

If patient is colonised with or considered to be high risk for MRSA, consider adding Vancomycin or Teicoplanin. (Please see Vancomycin / Teicoplanin dosing schedule).

* Please read the HPRA Drug Safety Alert issued in 2018 and the HPRA Drug Safety Newsletter issued in 2023 highlighting restrictions on use of fluoroquinolones (eg. ciprofloxacin, levofloxacin) due to the risk of disabling, long-lasting and potentially irreversible side effects (including tendon damage, QT prolongation, neuropathies and neuro psychiatric disorder). Use of fluoroquinolones in older patients, those with renal impairment, solid organ transplantation or on systemic corticosteroids increases the risk of tendon damage.

Comments

Review IV antibiotics by 48h

• consider switch to oral antibiotics if possible
• de-escalate to a narrower spectrum antibiotic based on microbiology test results

Duration 5-7 days depending on clinical course.

Antibiotics are not indicated for aspiration or aspiration pneumonitis without evidence of bacterial infection.

Hospital-Acquired Pneumonia - more than 5 days since admission

General Points

HAP > 5 days since admission OR any of the following:

• Severe pneumonia (symptoms or signs of sepsis)
• Ventilator-associated pneumonia
• Relevant co-morbidity such as severe lung disease or immunosuppression
• Recent use of co-amoxiclav or other broad-spectrum antibiotics
• Colonisation with an MDRO
• Recent contact with a health or social care setting before admission.
• Recent hospitalization in the last 90 days

-Check previous microbiology test results in particular for history of MDROs (MRSA, ESBL, and CPE).

-Send sputum or tracheal aspirate for culture.

-Send blood cultures if febrile or in sepsis.

-Consider Legionella. If suspected send urine for legionella antigen, sputum for Legionella culture and add clarithromycin empirically.  See section on legionellosis.

Antibiotics

First line:

Piperacillin-tazobactam 4.5g TDS/QDS IV (QDS dosing indication: severe infection, neutropenic sepsis, Pseudomonas aeruginosa infection, obesity)

+/- Gentamicin once daily IV. (Please see Gentamicin dosing schedule).

Penicillin allergy:

Non-IgE mediated /non-severe reaction:

Ceftriaxone 2g once daily IV+/- Gentamicin once daily IV. (Please see Gentamicin dosing schedule).

IgE mediated / anaphylaxis / severe reaction:

* Levofloxacin 500mg PO or IV BD ( excellent oral bioavailability ) +/- Gentamicin once daily IV (Please see Gentamicin dosing schedule).

Add Metronidazole 500mg TDS IV or 400mg TDS PO ( excellent oral bioavailability) in aspiration pneumonia.

Note: treatment of aspiration pneumonia does not require addition of metronidazole to either piperacillin-tazobactam or co-amoxiclav as both provide sufficient anaerobic cover.

Use Amikacin instead of gentamicin if septic shock or if history of gentamicin resistant gram-negative bacteria. (Please see Amikacin dosing schedule ). Review aminoglycoside use daily.

If patient is colonised with or considered to be high risk for MRSA, consider adding Vancomycin or Teicoplanin. (Please see Vancomycin / Teicoplanin dosing schedule)

If history of colonisation or infection with ESBL -producing organism, Meropenem may be indicated. Restricted agent, discuss with microbiology.

If known colonisation with CPE discuss with microbiology.

* Please read the HPRA Drug Safety Alert issued in 2018 and the HPRA Drug Safety Newsletter issued in 2023 highlighting restrictions on use of fluoroquinolones (eg. ciprofloxacin, levofloxacin) due to the risk of disabling, long-lasting and potentially irreversible side effects (including tendon damage, QT prolongation, neuropathies and neuro psychiatric disorder). Use of fluoroquinolones in older patients, those with renal impairment, solid organ transplantation or on systemic corticosteroids increases the risk of tendon damage.

Comments

• Stop aminoglycoside when patient stable or if pathogen tests susceptible to primary antibiotic. Treatment beyond 3 days is rarely indicated.
• Review IV antibiotics at 48h and consider switching to oral antibiotics if possible.
• Review antibiotic choice based on microbiological results and switch to a narrower spectrum antibiotic when appropriate.
• Note the combined use of Piperacillin/tazobactam and Vancomycin together is associated with an increased risk of acute kidney injury. Stop vancomycin if no evidence of MRSA.
• Antibiotics are not indicated for aspiration or aspiration pneumonitis without evidence of bacterial infection.
• Duration: Review at 5 days. Longer duration may be required if infection due to Pseudomonas aeruginosa , MSSA or MRSA, infection complicated by abscess formation, cavitation, necrosis, empyema or if occurring in immunocompromised patients.

References

1. International ERS/ESICM/ESCMID/ALAT guidelines for the management of hospital-acquired pneumonia and ventilator-associated pneumonia. Eur Resp J 2017; 50:1700582.
2. Pneumonia (hospital acquired): antimicrobial prescribing NICE guideline Published: 16 September 2019.
3. COVID-19 rapid guideline: antibiotics for pneumonia in adults in hospital. NICE 1 ^st May 2020.
4. I Bellos et al. Acute Kidney Injury Following the Concurrent Administration of Antipseudomonal β-lactams and Vancomycin: A Network Meta-Analysis. Clin Microbiol Infect 2020 Jun; 26(6):696-705.

Infective Exacerbation of COPD

General Points

Consider antibiotic therapy in severe exacerbation requiring assisted ventilation, or, if 2 or more of the following are present:

• Increased breathlessness
• Increased sputum volume
• Sputum purulence

If consolidation on Chest X-ray treat as CAP.

Send sputum for culture.

Send blood cultures if febrile, septic or severe exacerbation.

Review previous sputum culture results in particular for evidence of colonisation/infection with Pseudomonas aeruginosa.

Antibiotics

Comments

• Ensure all patients offered annual influenza vaccine prior to hospital discharge if during flu season and appropriate to do so. See National Immunisation Guidelines for more details.
• Check pneumococcal vaccine status and arrange vaccination if required.