Treatment of pneumonia with antibiotic and empirical therapy

To find the most appropriate therapy for pneumonia, the doctor must:

  • make an accurate diagnosis,
  • carry out necessary investigations to identify the cause.


Guideline for the treatment of pneumonia in adults

(Protocol of the University of Modena and Reggio Emilia, Italy)

Diagnosis and examination of pneumonia

The doctor must know exactly the anamnesis, first of all:

  • Age
  • Living and working habits
  • Other diseases
  • Allergy to medication
  • Epidemic in the visited environment
  • Socioeconomic status

After that, the doctor performs the physical examination.

X-ray of the chest

  • In an outpatient if pneumonia is suspected, an X-ray is not absolutely necessary
  • In an inpatient it is always recommended to perform a chest X-ray examination

If the course of pneumonia is benign, chest X-ray control examination is not required.
However, the doctor may order this examination, but at the earliest 2-3 weeks after the start of therapy with antibiotics.
Radiography (or CT) is recommended within 6 weeks if:

  • the symptoms do not improve,
  • Patients are at high risk of lung cancer (for example, smokers, patients > 50 years of age, etc.)

Blood test
Upon admission to the hospital, the recommended blood tests are:

  • Complete blood count,
  • indications of kidney and liver function,
  • blood sugar,
  • Electrolytes (used to calculate points PORT, a rating scale of patient condition).

Microbiological tests
For the majority of patients treated at home, microbiological tests are not necessary.
Upon admission to hospital, the following examinations must be carried out:

  • Blood culture (before starting antibiotic therapy), even if the patient does not have a fever
  • Sputum culture (secretion of the respiratory tract) and bacteriological examination (examination performed at a microscope to identify responsible bacteria).
  • Gram staining and possibly search for alcohol- and acid-resistant bacteria.

Cultivation serves only to obtain a corresponding germ from the expectorate without delaying antibiotic therapy.

These examinations are recommended, even if they are not always useful for diagnosis, as they:

  • are simple,
  • incur little cost,
  • provide an almost certain result in pneumonia caused by mycobacteria, Pneumocystis carinii or endemic fungi.

In patients in intensive care, an appropriate sample must be obtained for diagnosis, including by:

  • a bronchoscopy,
  • a bronchial lavage.

Performing a single blood test is of no use in the choice of empirical therapy (test results are not enough, statistical surveys are also needed).
Repetition of the blood test is useful for assessing the course of pneumonia.

Pleural puncture
Pleural puncture is recommended in all patients with significant pleural effusion.

Arterial blood gas analysis
Arterial blood gas analysis (or O2 saturation) is recommended for all patients upon hospitalization.

When should patients with pneumonia be hospitalized?

The following are to be evaluated:

  • state of health of the patient,
  • contraindication to home treatment,
  • Severity of pneumonia.

One must also consider risk factors such as:

  • A possible treatment with corticosteroids
  • Alcoholism
  • Antibiotic therapy
  • Stay in a nursing home
  • Age

There are rating indices (scores) in order to ultimately be able to make the right decision.

Patient rating according to PSI or PORT rating index

The PSI (Pneumonia Severity Index) or PORT score is a score chosen to assess the risk of death in patients with pneumonia.

The score comes from data from 38,000 patients in a 1989 Medis Group cohort study based on a year-long survey of 257 hospitals in the United States under the supervision of Mediqual Systems.

The PSI point system is used to decide where patients with pneumonia can be treated:

  • At home
  • In the hospital

Patients are divided into 5 risk classes, which serve to assess the chances of survival for a period of 30 days.

  • Class I patient can be treated at home with oral antibiotics.
  • Class II-III patient can:
    • Treated with antibiotics at home or
    • Be monitored 24 hours in hospital.
  • class IV-V patient, on the other hand, should be admitted to the hospital for treatment.

The score is obtained by assigning values to 19 variables.
The sum is collected and, depending on the total value, the patient is assigned to a category.

Weaknesses of the PORT criteria

  • Many parameters have to be evaluated
  • The patient’s hypoxia is not taken into account
  • Social factors are not taken into account
  • The survey is only carried out from the age of 50
  • No factors that may worsen the clinical condition of the patient (HIV and neuromuscular diseases) are taken into account.


CURB 65 is an assessment system designed to help the physician care for a patient with pneumonia based on the risk of death:

  • Low
  • Medium
  • High

CURB 65 effectively identifies patients with pneumonia and high mortality risk, but not those with reduced risk, who can be treated at home.

CURB 65 assesses risk factors:

  • Confusion
  • Serum urea above 7 mmol/l
  • Respiratory rate more than 30 puffs per minute
  • Systolic blood pressure (maximum) less than 90 mmHg and diastolic blood pressure (minimum) less than 60 mmHg
  • Patient older than 65 years.

The index assigns 1 point for each risk factor present, so the total value is between 0 and 5. The data comes from 3 large studies involving 1,068 patients selected to create and test CURB 65.

In patients in whom it was not possible to obtain information about the level of urea in the blood, CURB 65 can be used, as the level of blood urea is not taken into account.

Use of the assessment system CURB 65

Scale from 0 to 5

  • 0-1 – the patient can stay at home,
  • 2 – the patient must be hospitalized,
  • 3 – high risk of death,
  • 4-5 – Treatment in intensive care.

Increase in the risk of death according to CURB 65

TotalIncrease in mortality risk %









Indication for immediate hospital admission

  • Oxygen saturation < 90%
  • Hemodynamic instability (circulatory problems))
  • Unreliability of the patient
  • The patient suffers from another disease, so hospitalization is recommended

For all other patients, the severity of pneumonia should be determined according to the Pneumonia Severity Index.

Other factors that require hospitalization:

  • The presence of certain microorganisms (such as Staphylococcus aureus)
  • Prognostically unfavorable factors
  • Involvement of at least two lobes of the lung
  • Infectious complications (for example, empyema or septic arthritis)
  • Some signs such as hypotension or hypoxemia (low oxygen in the blood) in patients otherwise in classes I, II and III
  • Difficulties with outpatient treatment success and inadequate home support
  • The decision to discharge the patient should be based on similar considerations

Criteria for the treatment of a patient with pneumonia

Clinical criteria

  1. Respiratory rate equal to or greater than 30 per minute
  2. Heart rate equal to or more than 120 beats/minute
  3. Systolic blood pressure equal to or less than 90 mmHg and diastolic blood pressure equal to or less than 60 mmHg
  4. Recent confusion

If the patient meets at least 2 of the clinical criteria, pneumonia is severe.

Treatment of pneumonia

There are two types of treatment:

Targeted: when the responsible micro-organism has been identified with certainty.

Targeted therapy is carried out in the following way:

  • secretion removal from the area of infection,
  • sending the material to the laboratory,
  • isolation of the micro-organism,
  • Sensitivity test of the antibiotic (antibiogram).

Empirically: if the doctor does not know the cause of pneumonia.
There are parameters that, even without analysis, indicate which type of microorganism is responsible.
Depending on the clinical picture, the season, etc., one tries to classify pneumonia and uses an antibiotic suitable in this context (the choice of antibiotic changes mainly depending on whether the patient is hospitalized or treated at home).

The choice of antibiotic depends on:

  • Location of infection
  • Inpatient or home stay
  • Signs, symptoms and course of pneumonia
  • Season
  • Characteristics of the patient

According to the guidelines, the doctor should prescribe the antibiotic based on the typology and etiology of pneumonia and one should start antibiotic therapy, even if the pathogen has not been isolated.

Antibiotic therapy for pneumonia

Treatment of a patient with community-acquired pneumonia

  • Healthy person – macrolide (azithromycin or clarithromycin) or fluoroquinolone
  • High-risk patient with other disorders (cardiopulmonary disease, liver disease, alcoholism, neoplasia, missing spleen, etc.) – macrolide + β-lactam antibiotic (amoxicillin/clavulanic acid and ceftriaxone) or fluoroquinolone alone

As a rule, intravenous treatment is given to a high-risk patient.

Therapy of an inpatient in the Medical Department

  • Low-risk patient – macrolide (first choice: azithromycin alone 500 mg intravenously for 5 days, then oral for 7-10 days)
  • Risk patient – macrolide intravenously + β-lactam antibiotics (cefotaxime, ceftriaxone and ampicillin / sulbactam or amoxicillin/clavulanic acid) or fluoroquinolone alone intravenously.

Treatment for community-acquired pneumonia, patient in intensive therapy

Occurs mainly for:

  • Streptococcus pneumoniae,
  • Legionella,
  • Haemophilus influenzae.

1) Patient at risk of Pseudomonas infection

  • Makrolid+ β-lactam, both intravenously (ampicillin / sulbactam, amoxicillin / clavulanic acid and cephalosporin of the second and third generation),
  • quinolone + β-lactam intravenously (ampicillin / sulbactam, amoxicillin / clavulanic acid and cephalosporin II – III generation)

2) If there is a risk of Pseudomonas infection (bronchiectasis or cystic fibrosis)

  • β-Lactam Anti-Pseudomonas intravenous (ceftazidime, cefepime, imipenem, meropenem and piperacillin / tazobactam) + quinolone anti-pseudomonas intravenous (ciprofloxacin)
  • β-lactam + aminoglycoside or azithromycin
  • β-lactame + aminoglycoside or quinolone

Caution: Aminoglycoside can be toxic to the kidneys.

3) Patient with MRSA infection (methicillin-resistant Staphylococcus aureus)

You can add vancomycin (here you have to ask the infectologist)

Treatment of nosocomial (hospital-acquired) pneumonia

β-lactam + aminoglycoside + fluoroquinolone

  • Pseudomonas aeruginosa: β-lactam anti-pseudomonas + fluoroquinolone anti-pseudomonas,
  • Staphylococcus aureus resistant to methicillin: vancomycin or teicoplanin,
  • Legionella: macrolides or fluoroquinolone,
  • Anaerobes: clindamycin or β-lactam.

Treatment of pneumonia in immunosuppressed patients

Empirical therapy for gram-positive and gram-negative bacteria (if no antibiogram is available)


β-lactame (third-generation cephalosporins) with and without aminoglycoside

  • Gram-positive methicillin-resistant: vancomycin,
  • Pneumocystis: co-trimoxazole,
  • Viral pneumonia: antiviral,
  • Fungal pneumonia (in transplanted patients): antifungal drug.

Duration of therapy for pneumonia

Usually, antibiotic treatment begins in the first 8 hours of hospitalization.
Three days later, you have to check the clinical picture to see if there are improvements.
If the therapy responds, you can see the results on the third day:

  • Decrease in fever and/or leukocytosis (increase in white blood cells)
  • Decrease in PCR levels

In other cases, it is necessary to re-evaluate therapy.
The duration of therapy depends:

  • From the responsible micro-organism
  • On the response of initial therapy
  • From the presence of other diseases
  • Of complications

It must not last less than 5 days.

Drug therapy lasts:

  • With pneumococcal pneumonia 3–5 days after the patient no longer has a fever, usually therapy lasts 10 days.
  • For very dangerous microorganisms (mycoplasma, chlamydia or legionella), therapy can also take 2–3 weeks.

Therapy is started according to the symptoms of the patient and the responsible microorganism, even without identification of the bacterium.

Criteria of therapy interruption in pneumonia

  • Temperature ≤ 37° C for at least 48-72 hours
  • Heart rate ≤ 100 beats per minute
  • Respiratory rate ≤ 24 breaths per minute
  • Oxygen saturation ≥ 90%
  • Arterial blood pressure ≥ 90 mmHg
  • Proper nutrition and hydration
  • Mental state normal or corresponding to the previous state
  • No other diseases for which the patient must be hospitalized.

These parameters indicate that the patient is stable. From there:

  • Is it possible to stop therapy.
  • Can the patient be discharged home.

The most important criteria are: The patient must be fever-free for at least 2-3 days.

Antibiotic injection or taking tablets for pneumonia?

In hospitalized patients, intravenous antibiotic therapy is started if:

  • The patient is seriously ill
  • No appropriate oral antibiotic is available
  • The patient has difficulty taking or absorbing the medication orally

3 days after the start of intravenous therapy, the drug can be given orally if:

  • There is clinical improvement and reduction in white blood cells
  • The temperature ≤ 38° C is
  • There are no gastroenteral problems (malabsorption, disability, etc.)

Empirical therapy for pneumonia does not work in the following cases

  • Diagnostic error, the patient could have another condition, for example:
  • Patient-dependent factors such as narrowing or presence of foreign bodies
  • Inadequate treatment response due to immunosuppression
  • Occurrence of complications: empyema, abscess, sepsis or septic shock
  • Treatment-resistant germ
  • Wrong antibiotic:
    • Active substance
    • Dose
    • Form of administration
  • Interaction with other drugs

Antibiotic resistance in pneumonia

  • 11% of Streptococcus pneumoniae strains are resistant to penicillin
  • 28.6% of Streptococcus pneumoniae strains are resistant to erythromycin
  • 24.3% of Streptococcus pneumoniae strains are resistant to tetracycline
  • No strain is resistant to ceftriaxone or ofloxacin

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