This document provides information on pneumonia caused by bacteria and viruses in different patient populations. It discusses the typical causes and treatment of community-acquired pneumonia (CAP) in both children and adults, as well as hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). The most common bacterial causes of CAP include Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and respiratory viruses. HAP and VAP are often caused by more resistant hospital-acquired bacteria like Pseudomonas aeruginosa, Acinetobacter, and Klebsiella pneumoniae. Empiric antibiotic therapy and targeted treatment are outlined based on patient risk factors and pathogen susceptibility.

1. Vinnitsa National Pirogov Memorial Medical University/
Department of microbiology
Lecturer: ass.-prof.Vovk I.M.
Bacteria causing hospital and secondary
bronchitis and pneumonia, specificity of
etiology in different age groups.
Ventilator-associated pneumonia
(VAP). Laboratory diagnostics.

2. ACUTE BRONCHITIS
▶ Acute bronchitis is a self-limited syndrome characterized by
acute cough with or without sputum but without signs of
pneumonia
▶ Acute bronchitis is primarily caused by viral infections. Most
common are rhinovirus, influenza viruses, respiratory syncytial
virus, metapneumovirus, coronaviruses, and adenovirus. Fewer
than 10% of cases are caused by Mycoplasma pneumoniae,
Chlamydia pneumoniae, and Bordetella pertussis

3. ▶ 50% of smokers; fourth leading cause of death worldwide
▶ Risk factors: cigarette smoking, environmental particulate
matter, genetic predisposition
▶ Intermittent progressive airway inflammation;
▶ remodeling and loss of lung function
▶ Ciliary dysfunction;
▶ excess mucus production;
▶ impaired phagocytosis leading to
bacterial colonization
CHRONIC OBSTRUCTIVE
PULMONARY DISEASE (COPD)

4. CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD)
▶ Airways of patients with stable disease are frequently colonized with Streptococcus
pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis; respiratory
syncytial virus is most frequent colonizing virus.
▶ • Microaspiration in stable disease introduces oral anaerobes (e.g., Prevotella and
Veillonella spp.) into lower airway.
▶ • During acute exacerbation, bacteria or viruses or both may be isolated, with more
gram-negative rods found with worsening lung function.
▶ “Atypical” bacteria are not frequently isolated.
▶ Oral or intravenously administered corticosteroids and early empirical
antibiotic therapy (azithromycin) are advised for moderate to severe
exacerbations
▶ Administer influenza, pneumococcal, and pertussis vaccines.

5. Pneumonia is a form of acute lung
infection. It can cause mild to life-
threatening illness in people of all ages.
Some facts:
People at-risk for pneumonia include
children (≤ 5 y.o), adults over the age of 65
and people with preexisting health problems
It is the single largest infectious cause of
death in children (15% of death)
Ventilator-associated pneumonia (VAP)
takes the second-third place among causes
of death for ICU inpatients

6. ACUTE PNEUMONIA
Classification:
▶ Community-acquired pneumonia (CAP)
▶ Hospital-acquired pneumonia (HAP) or medical care
associated pneumonia (MCAP)
▶ Ventilator-associated pneumonia (VAP) in ICU
According to a cause:
▶ bacterial (more often, also named typical),
▶ other bacterial pathogens cause so named atypical pneumonia
(Chlamydia, Mycoplasma)
▶ Viral
▶ Fungal
▶ Protozoan
▶ Co-infection (bacteria + viruses is the most often)

7. •Diabetes mellitus
•Alcoholism
•Malignancy
•Asplenia
•Age over 65 y.o.
•Chronic heart, lung, liver or renal disease
Risk factors
for severe
CAP in
adults:
• Age under 5 y.o.
• Respiratory tract abnormalities
• Undernutrition
• Congenital/perinatal infections, including HIV
• Not complete immunization/no immunazation
• Heart and lung disease
• Cystic fibrosis, CGD
Risk factors
for severe
CAP in
children:
Community-acquired pneumonia (CAP) is an acute lung
inflammation caused by microorganisms acquired outside a
hospital or other medical facilities

8. In adults
•Streptococcus
pneumoniae*
• Haemophilus
influenzae
• Mycoplasma
pneumoniae
•Staphylococcus
aureus
•Legionella
pneumoniae
•Moraxella
catarrhalis
In children: school
age
•Chlamydia
pneumoniae
•Streptococcus
pneumoniae*
•Mycoplasma
pneumoniae
Newborns
•Streptococci B
group
(S.agalactiae)
•Listeria
monocytogenes
•Escherichia coli
In children:
preschool age
•Streptococcus
pneumoniae*
•Staphylococcus
aureus
•Haemophilus
influenzae*
Bacterial pneumonia: causes of CAP
* -not for immunized with pneumococcal vaccine/Hib vaccine

9. OTHER CAUSES OF CAP:
•SARS-CoV2
•Influenza virus
•Adenovirus
•SARS and MERS viruses
•Human metapneumonic viruses
Viruses: in adults
•CMV and HSV for neonates
•Respiratory-syncytial virus (first 12 months)
•Influenza virus
•Measles virus
•Varicella/zoster virus
•Adenoviruses, rhinovirus
Viruses: in
children
•Candida albicans, molds for
immunodeficient people
•Pneumocystis jirovecii for AIDS patients
Fungi and
protozoa

10. LABORATORY DIAGNOSTICS: SAMPLING AND MODERN
APPROACHES
▶ Sputum sample: Gram`s stain and culture*
▶ Endotracheal aspirate sample in intubated patients: Gram`s stain, culture,
antibiotic susceptibility testing
▶ Nasopharyngeal swab or oropharyngeal swab for influenza/ covid 19 testing
(in case is co-infection or viral pneumonia suspected): PCR is more preferable
than rapid test
▶ Urine: pneumococcal antigen and Legionella antigen testing at suspicion for
severe CAP, caused by this pathogens
▶ Blood: Blood culture in patients with severe disease as well as in all inpatients
empirically treated for MRSA or P.aeruginosa OR patients with medical care-
associated pneumonia (MCAP)
* According to An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of
America(2019) it is not recommended for adult outpatients with CAP because of low quality of evidence

11. GRAM STAIN OF SPUTUM
Streptococcus pneumoniae in patient`s sputum (left on
the top)
Staphylococci in the patient`s sputum (left on the bottom)
Normal sputum smear with epithelial cells and
oropharyngeal microbiome but without WBC (on the right)

12. Haemophilus Influenzae
on chocolate agar
Legionella pneumophilia on
buffered charcoal yeast extract
agar (BCYE)
Streptococcus pneumoniae
on blood agar

13. EMPIRIC THERAPY FOR CHILDHOOD
CAP
Bacterial pneumonia Atypical pneumonia Influenza pneumonia
Outpatients (3m.-18 y.) Amoxicillin OR
amoxicillin/clavunate
(orally)
Azitromycin OR
clarithromycin (orally)
Oseltamivir
Inpatients fully
immunized against
S.pneumoniae and
H.influenzae type b
Ampicillin OR
Ceftriaxone/cefotaxime
(IV)
Vancomycin may be
added at suspected
MRSA
Azitromycin OR
clarithromycin/erythrom
ycin/doxycycline (IV)
Oseltamivir + Zanamivir
Inpatients not fully or not
immunized against
S.pneumoniae and
H.influenzae type b
Ceftriaxone/cefotaxime
OR
Levofloxacin (IV)
Vancomycin or
clindamycin may be
added at suspected
MRSA
Azitromycin+β-lactam
OR
clarithromycin/erythrom
ycin/doxycycline/levoflo
xacin (IV)
Oseltamivir +
Zanamivir (for children
older 7 y.)
Principles of antimicrobial therapy (CAP) in Children

14. PRINCIPLES OF ANTIMICROBIAL THERAPY (CAP) IN ADULTS
Category of patients Recommended therapy Adds
CAP in outpatients
without risk factors
and co-morbidities
Monotherapy:
Amoxicillin or Doxycycline or Azithromycin
Orally, not less than 5-days` therapy
CAP in outpatients
with risk factors and
co-morbidities
Combination: Amoxicillin/clavunate or
cefuroxime AND macroloide (azithromycin or
clarithromycin) or doxycycline OR
Monotherapy: respiratory flouroquinolone
(levofloxacin or moxifloxacin or Gemifloxacin)
Broader-spectrum antibiotics to
cover macrolide- and doxycycline-
resistant S. pneumoniae, b-
lactamase–producing strains of H.
influenzae, many enteric gram-
negative bacilli, most MSSA, and M.
pneumoniae and C. pneumoniae
Non-severe CAP in
inpatients
Β-lactam (ampicillin+sulbactam, cefotaxime,
ceftriaxone) AND macrolide (azithromycin,
clarithromycin) or doxycycline OR
Monotherapy with respiratory fluoroquinolones
Without risk factors for MRSA or
P.aeruginosa
Severe CAP in
inpatients
b-lactam plus a macrolide OR
b-lactam plus a respiratory fluoroquinolone
Without risk factors for MRSA or
P.aeruginosa
CAP in inpatients
with risk factors for
MRSA or
Vancomycin for MRSA
Piperacillin-tazobactam or cefepime or
ceftazidime or aztreonam, meropenem or
Risk factors: prior isolation of
MRSA/P.aeruginosa from respiratory
tract;

15. MEDICAL CARE –ASSOCIATED PNEUMONIA (MCAP)
HOSPITAL-ACQUIRED pneumonia (HAP), or nosocomial pneumonia, is a lower
respiratory infection that was not incubating at the time of hospital admission and
that presents clinically 2 or more days after hospitalization.
1. Early HAP happens 48-120 hrs after hospitalization. Main causes: S.pneumoniae,
H.influenzae, MSSA, M.catarrhalis, others. It has better prognosis
2. Late HAP arises over 120 hrs (6 days) after hospitalization. Main causes: MRSA,
K.pneumoniae and other enteric bacteria, non-ferments such as P.aeruginosa. Its
prognosis is worse, because multiresistant hospital isolates are quite often causes
VENTILATOR-ASSOCIATED pneumonia (VAP) is defined as nosocomial pneumonia
occurring in a patient after 48 h of mechanical ventilation via an endotracheal or
tracheostomy tube.
It is commonly classified as either early onset (occurring within 96 h of start of
mechanical ventilation) or late onset (occurring more than 96 h after start of
mechanical ventilation). VAP occurs in 9–27% of all intubated patients

16. Risk factors for nosocomial pneumonia
1. Patient-related factors: acute or chronic severe disease, coma,
malnutrition, prolonged hospital length of stay, hypotension,
metabolic acidosis, smoking and comorbidities (especially of the
central nervous system but also chronic obstructive pulmonary
disease (COPD), diabetes mellitus, alcoholism, chronic renal failure
and respiratory insufficiency).
2. Infection prevention-related : deficient hand hygiene or inappropriate
care of respiratory support devices
3. Procedures-related : administration of sedatives, corticosteroids and
other immunosuppressants, prolonged surgical procedures
(especially at thoracic or abdominal level) and
prolonged/inappropriate antibiotic treatment .

17. LABORATORY
SAMPLING FOR
PATHOGEN ISOLATION
Sampling:
Blind tracheobronchial aspiration (TBAS), which is a noninvasive
technique done by inserting a flexible catheter into the distal trachea
via the endotracheal tube.
Bronchoscopy with bronchoalveolar lavage (BAL) allows the sampling
of the lung segments which are suspected to be affected by
pneumonia
Protected specimen brush (PSB) which can be advanced through a
bronchoscope and has the advantage of avoiding contamination with
upper airway secretions
Blood for culture (!)
Microscopic Analysis
▶ polymorphonuclear leukocytes and a gram stain.
Quantitative Cultures: Diagnostic thresholds include:
• Endotracheal aspirates 1,000,000 colony forming units (CFU)/mL
• Bronchoscopic- or mini-BAL 10,000 CFU/mL
• PSB 1000 CFU/mL
Multiplex PCR assay for multidrug resistant genes detection

18. K.pneumoniae (on the left), Acinetobacter (in the center) and P.aeruginosa (on the right) in PSB-samples:
encapsulated bacteria

19. The most dangerous pathogens (being suspected for resistance to antimicrobial therapy):
1. Gram-negative enteric bacteria such as Klebsiella pneumonia (especially
ESBL-producers), Escherichia coli, Enterobacter spp.
2. Gram-negative non-ferments such as Pseudomonas aeruginosa and
Acinetobacter baumannii (rarely Stenotrophomonas maltophilia, Burkholderia
cepacia)
3. Gram-positive cocci including MRSA, VRSA, vancomycin-resistant
enterococci, macrolide-resistant streptococci
Some facts:
Late HAP and VAP are often caused by hospital isolates
Gram-negative microorganisms are predominant cause
Late MCAP are polymicrobial in 40-60% of cases

20. P.aeruginosa A.baumannii K.pneumoniae

21. PANNUCI algorithm. From empirical to targeted treatment on nosocomial pneumonia in ICU.
Empiric treatment:
Unknown colonization
•piperacillin-/tazobactam
or carbapenem or
cefepime PLUS
aminoglycoside or
Quinolone
Early onset without
previous AT
•Cephalosporins 3rd
P.aeruginosa risk factors /
vAP and/or AB failure
•Ceftazidime/avibactam
PLUS aminoglycoside OR
•Ceftolozane/azobactam
PLUS Quinolone
K.pneumoniae risk factors
for EBSL, KPC
•Ceftazidime/avibactam
PLUS aminoglycoside or
Quinolones
Targeted treatment
MRSA
•Linezolid or vancomycin
MSSA
•Cloxacillin or cefazoline
Acinetobacter
•colistin or cefideracol
P.Aeruginosa or/and
bacteremia
•Ceftolozane/azobactam
KPC or OXA-48
• Ceftazidime/avibactam
Metallo-beta-lactamases
• Ceftazidime/avibactam +AZT or
• colistin or cefideracol

22. WHILE COMPILING LECTURE MATERIALS
NEXT SOURCES WERE USED:
▶ Mandell, Douglas and Bennett`s Infectious Diseases Essentials/ J.E Bennet., R. Dolin, M.J.Blaser. –
ELSEIVER, 2017.
▶ Metlay J.P. et al. Diagnosis and Treatment of Adults with Community-acquired Pneumonia: An Official
Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of
America//American Journal of Respiratory and Critical Care Medicine (2019). – Vol. 200 (7). – P. e45-e67,
▶ Thorell E.A., M.A.Jackson. Community-Acquired Pneumonia: Implications for the Hospitalized Child// The
Hospitalist. 2005 September;2005(9)
▶ Chahine E. B. , Mayberry M. S. . Update on the Treatment and Prevention of Community-Acquired
Pneumonia in Children//US Pharm. 2012;37(3):HS-12-HS-15.
▶ Shebl E.; Gulick P. G. . Nosocomial Pneumonia. https://www.ncbi.nlm.nih.gov/books/NBK535441
▶ Zaragoza, R., Vidal-Cortés, P., Aguilar, G. et al. Update of the treatment of nosocomial pneumonia in the
ICU. Crit Care 24, 383 (2020). https://doi.org/10.1186/s13054-020-03091-2
▶ Illustration sources: https://www.wikiwand.com/; https://www.microbiologyinpictures.com/bacteria-
micrographs