Advances in the causes and management of community acquired pneumonia in adultsBMJ 2017; 358 doi: https://doi.org/10.1136/bmj.j2471 (Published 10 July 2017) Cite this as: BMJ 2017;358:j2471
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Causes and management of community acquired pneumonia in adults. Some practical points need to be highlighted in order to treat effectively and at the same time reduce harm.
I have read with interest the succinct article of Richard Wunderink and Grant Waterer.
I wish to highlight a number of relevant points in the management of community acquired pneumonia.
There is a difference in epidemiological behaviour between one geographical area and the other and therefore the causative infective agents responsible for this infection will vary depending on where the patients are. Although some pneumonias are caused only by viruses such as influenza A or Influenza B, however in many instances the initial respiratory infection is due to a viral agent and then the pneumonia manifests as a result of secondary bacterial infection. Although the list in the article is quite comprehensive however there are still important causative organisms that need to be mentioned such as Staphylococcus aureus including the PV ( Panton-Valentine) producing strains that may cause life threatening pneumonias in younger age groups, Haemophilus influenza and Moraxella catarrhalis.
1. Check for previous microbiology results relevant to the respiratory tract as this will guide towards the more correct use of antimicrobials.
2. Check for previous alert organisms i.e. Meticillin resistant Staphylococcus aureus (MRSA), ESBL producing organisms, Glycopeptide-resistant Enterococci (GRE), Clostridium difficile and Carbapenemase-producing Enterobacteriacae (CPE).
The rationale is they may be responsible for the pneumonia hence they would then need to be targeted, or we need to be mindful that the antimicrobials used should not promote selecting them and, therefore their emergence in the form of colonisation or even subsequent infections.
3. In the majority of cases it is not possible to obtain a sputum sample from the infected patient unless when the patient has chronic pulmonary disease such as COPD.
4. A urine sample needs to be sent to the Laboratory for pneumococcal and Legionella direct antigen detection.
5. If an atypical pneumonia is suspected then a virology swab of the throat needs to be obtained for detection of Mycoplasma pneumonia and Chlamydia pneumonia DNA by the method of PCR.
6. If a viral infection is suspected as a cause of the pneumonia or as the primary respiratory infection then a virology swab needs to be taken for PCR testing that will identify a list of viruses that may be responsible for the respiratory infections whether upper or lower.
7. Last but not least is the need to take a blood culture sample if the patient is septic with a serious pneumonia. In many occasions Streptococcus pneumonia can be isolated from blood cultures only in patients with pneumococcal pneumonias.
• The use of Amoxicillin and Clarithromycin as empirical therapy would be a reasonable approach particularly when the patient’s CURB60 score is less than 3. Amoxicillin will cover the vast majority of pneumococci and Haemophilus influenza
• If the pneumonia is more serious i.e. CURB60 score 3 or more, then a more broad-spectrum antimicrobial i.e. Co-Amoxiclav along with Clarithromycin may be used instead.
• Once the causative organism is identified microbiologically then antimicrobial treatment should be rationalised by only continuing with the least broad-spectrum agent and stopping the inappropriate ones.
• A typical example is following the initiation of intravenous Co-Amoxiclav and Clarithromycin to treat a serious pneumonia, when Streptococcus pneumonia is isolated from the blood culture then only intravenous Benzyl penicillin should be used and the other two agents stopped.
This constitutes best practice and is at the heart of antimicrobial stewardship as it will inevitably lead to less emergence of antimicrobial resistance, less emergence of Clostridium difficile and less collateral damage.
• Antimicrobial prescribing and stewardship is at the heart of infection prevention and control.
The take home message is: Management of serious infections including pneumonias entails checking previous microbiology results including evidence of alert organisms that are known to cause healthcare associated infections and taking the right samples for laboratory testing in order to guide antimicrobial therapy.
But once a microbial diagnosis is made then initial empirical therapy needs to be changed towards the least broad-spectrum or preferably mono-spectrum agents with the shortest duration of treatment.
Effective management of pneumonias means effective eradication of the infective agent but at the same time effective prevention of the emergence of other harmful infective agents.
Competing interests: No competing interests