Download Pneumonia Causative Organism

Pneumonia Causative
Organism
By: Yomna mamdouh
Pharm D student
Definition of Pneumonia :

It’s an respiratory disease characterized by
inflammation of the lung parenchyma
(excluding the bronchi) with congestion
caused by,bacteria, virus,fungi or irritants.
Classification of pneumonia :(clinically)
Pneumonia
Community
Acquired
Pneumonia
Pneumonia in
Immunocompromised
patients
Hospital
Acquired
Pneumonia
Community Acquired Pneumonia

Community-acquired pneumonia :
Refers to pneumonia acquired outside of
hospitals or extended-care facilities.
Community Acquired Pneumonia
Epidemiology:
4-5 million cases annually
~500,000 hospitalizations
~45,000 deaths
Mortality 2-30%
 Probably highest incidence occur in ages between 25-65 yrs
Bartlett. CID 1998;26:811-38
Incidence
1400
1171 1207
1200
1000
1071
898
800
684
600
# of cases
# in
400
1000s
200
83
0
<5
5 to 18-24 25-44 45-64 >65
17
AGE
Causative Organism in community acquired pneumonia
Streptococcus pneumoniae (most common cause of CAP)
Hemophilus influenzae
Chlamydia pneumoniae
Mycoplasma pneumoniae
Legionella spp.
Staphylococcucs aureus
Viruses (e.g. adenoviruses, influenza viruses,
metapneumovirus, HIV and parainfluenza virus)
Frequency
Pathogen
Cases (%)
Streptococcus pneumoniae
20-60
Haemophilus influenzae
3-10
Staphylococcus aureus
3-5
Legionella species
2-8
Mycoplasma pneumoniae
1-6
Chlamydia pneumoniae
4-6
Viruses
2-15
Hospital acquired pneumonia




It describes pneumonia acquired
during hospitalization.
It develops after 48 hours admission in
hospital.
It’s neither detected nor incubated at
admission.
Ventilator-associated pneumonia (VAP) is
defined as pneumonia that occurs after 48-72
hours of endotracheal intubation.
Types by origin:
1.Endogenous:
Caused by organism that are present
as normal flora of the patient.
e.g. Staphylococcus aureus
2. Exogenous:
Caused by organisms acquiring by
exposure to hospital personnel,
medical devices or hospital
environment.
Causative Organism in Hospital acquired pneumonia
Aerobic gram positive cocci bacteria
 Methicillin-resistant Staphylococcus aureus (MRSA)
Aerobic gram-negative bacilli bacteria





Pseudomonas aeruginosa
Klebsiella pneumoniae
Acinetobacter species e.g.(Acinetobacter baumannii)
Escherichia coli
Enterobacteriaceae
Pneumonia in Immuno compromised
patients

Pneumonia in the immunocompromised host
involves infection and inflammation of the
lower respiratory tract. Regardless of the
reason for altered immune function,
pneumonia carries a high mortality rate in
immunocompromised patients.
Causative Organism of pneumonia in immunocompromised patients
Bacteria
Viruses
Fungi
Other
Chlamydia
pneumoniae
Cytomegalovirus
(CMV)
Aspergillus spp.
Pneumocystis
carinii
Pseudomonas
aeruginosa
Herpes zoster virus
Cryptosporidium
spp.
Mycobacterium
Respiratory syncytial Candidia
Mycobacterium tuberculosis
tuberculosis
virus
Streptococcus
pneumoniae
Picornaviruses
Fusarium
Haemophilus
influenzae
Adenoviruses
Cryptococcus

Pneumocystis carinii, has been classified to
be the most causative organism of
pneumonia in people with compromised
immune systems, such as those with AIDS or
undergoing cancer treatment.
Differences:
The spectrum of potential pathogens associated with HAP differs
from that of CAP and in immunocompromised patients.
 In Hospital acquired pneumonia
Common pathogens include aerobic gram-negative bacteria
(e.g., Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia
coli) rarely causes community-acquired pneumonia.
 In Immuno compromised patients pneumonia is caused by either
bacteria, Viruses or fungi.
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