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Hospital acquired
Pneumonia
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Respiratory Block - Microbiology Team 438

Objectives :
● Define the terms, pneumonia, community acquired pneumonia, health care associated pneumonia

● ( HCAP) and ventilator associated pneumonia (VAP).

● Describe the pathogenesis of the health care associated pneumonia (hospital associated pneumonia ) and VAP.

● Classify HCAP according to the time of onset .

● Name the different causative bacterial agents . Classify and describe types of VAP.

● Recognize the ways by which VAP is prevented.

● Describe the different chemotherapeutic antimicrobial agents used for the treatment of health care associated

pneumonia.

● Evaluate response to treatment and recognize reasons for failure of treatment.

 Pneumonia : infection of the pulmonary parenchyma.

● acquired in the community .

community acquired pneumonia ● The organisms causing it usually susceptible To antibiotics.
Example: Streptococcus Pneumonia

● acquired at least1 48 hours (and not incubating) after admission

Health care associated pneumonia to health care institutions .
( Nosocomial pneumonia ) ● The organisms causing it usually resistant to antibiotics.
Example : Pseudomonas Aeruginosa
1
: If the symptoms occur before 48 hours (2 days) , then the infection is acquired from the
Hospital Acquired Pneumonia community not the hospital ( CAP not HAP)
(HAP)

Ventilator Associated ● in patients with assisted respiration

Pneumonia (VAP) (mechanical ventilation) for a period at least 48
hours.
Epidemiology of Nosocomial Pneumonia :
● Nosocomial pneumonia is the 2nd most common hospital-acquired infections after urinary tract infection
● Nosocomial pneumonia is the leading cause of death from hospital-acquired infections.
● The incidence of nosocomial pneumonia is highest in ICU (intensive care unit) patients.
● The incidence of nosocomial pneumonia in ventilated patients (VAP) is 10-fold higher than non-ventilated patients
● The reported crude mortality for HAP is 30% to greater than 70%.
Pathogenesis of Nosocomial Pneumonia

Significant impairment of host defenses .

Introduction of a sufficient-size (high amount) inoculum
For pneumonia to occur, at least to overwhelm the host's lower respiratory tract defenses
one of the following three introduction of highly virulent organisms
conditions must occur: into the lower respiratory tract

The introduction caused most commonly by

microaspiration of oropharyngeal secretions
colonized with pathogenic bacteria.

Pathogenesis :
 Pathogenesis of Ventilator Associated Pneumonia
Pathogenesis :
Mechanical ventilation prevents mechanical clearance by cough and the
1 mucociliary escalator.
1
2
Bacterial colonization of the aerodigestive tract
2

Aspiration of contaminated secretion into the Lower airway 3

3

Prevention For VAP by oral decontamination

By oral regimen : Gentamicin, Colistin ,Vancomycin cream Pharmacologic strategies
When we have patients with assisted (Treat treating oropharyngeal colonization could prevent VAP)
respiration , we should do some of
these procedures to prevent Ventilator Non-pharmacologic strategies ● Stress-ulcer prophylaxis
● Combination antibiotic therapy
Associated Pneumonia (VAP): ● Prophylactic antibiotic therapy
-Effective hand washing and use of protective gowns and ● Chlorhexidine oral rinse
gloves ● Prophylactic treatment of neutropenic patients
-Semirecumbent positioning (prevention of aspiration) Vaccines
-Avoidance of large gastric volume
-Oral (non-nasal) intubation
-Continuous subglottic suctioning
-Humidification with heat and moisture exchanger
-Posture change
Classification of nosocomial pneumonia
(According to the onset)

Early-onset nosocomial pneumonia

Occurs during the first 4 days of admission.
By Classifying Pneumonia
according to the onset ,
Late-onset nosocomial pneumonia
● S. pneumoniae occurs more than 4 days of admission.
we can identify the group
of organisms causing it . ● MSSA (Methicillin sensitive S.Aureus)
● H.Influenza
● Anaerobes ● Gram negative organisms , like:
Pseudomonas aeruginosa , Acinetobacter
● Enterobacteriaceae , like :
(Klebsiella, Enterobacter, serratia)
● MRSA (Methicillin resistance S.Aureus)

In the case of VAP , the Classification is :

Note :The same Principle Early-onset VAP

Applied to VAP , but we within 48-72 hours after tracheal intubation
start counting the days
of The onset of the
Late-onset VAP
disease from the tracheal after 72 hours after tracheal intubation
intubation , not from the
Admission to the
hospital
Causative Agents
Enteric Gram negative bacilli
most frequently in patients:
● With late-onset disease
● with serious underlying disease often Pseudomonas aeruginosa , Acinetobacter
already on broad-spectrum antibiotics.
(Prior use of broad-spectrum antibiotics and an immunocompromised
state make resistant Gram-negative organisms more likely.) most frequently in patients:
With late-onset pneumonia.
S. aureus
●
● in ventilated patients.
The frequency of ICU-acquired P. aeruginosa carriage or
colonization/infection was 23.4% at 7 days and 57.8% at 14 days.

most frequently in patients:

● Ventilated patients after head trauma,
Anaerobes
neurosurgery, and wound infection.
● received prior antibiotics. most frequently in patients:
● Prolonged care in ICU. ● predisposed to aspiration .
● anaerobes occurred more often with
Specially MRSA(methicillin resistant S.aureus) is oropharyngeal intubation than
commonly in patients who: nasopharyngeal intubation.
● Received corticosteroids
● Undergone mechanical ventilation >5 days
● Presented with chronic lung disease
 Treatment of Nosocomial Pneumonia
-Most initial therapy is empiric (not specific for a pathogen), because the pathogen is not identified or results are not available when antimicrobial decisions are made in most patients , So :
1. Initially be treated with a broad- spectrum antibiotic regimen aimed at covering all likely bacterial pathogens .
2. This regimen should subsequently be narrowed, according to the result of culture.
Dr note:
● these groups help us to guess the pathogen , by
using the patient status .
American Thoracic Society has divided patients into three groups, each with a set of probable pathogens : ● Guessing the pathogen help us to choose a more
specific Empiric antimicrobial therapy

1 Group 1 3 Group 2 2 Group 3

mild to moderate HAP with no risk factor mild to moderate HAP with risk factor a-severe HAP , early-onset with no risk factor
b-severe HAP , late-onset or with risk factor

● mild to moderate HAP , monotherapy has been shown to be effective

● severe HAP in which infection with resistant organisms is likely, combination therapy probably should be instituted until culture result are available.

note: Synergy means :cooperation of two agents to produce an effect larger than the
Antibiotics used in HAP sum of their separate effects.

● Vancomycin + Linezolid (better due to less nephrotoxicity) ● Combination of Antipseudomonal drugs

There is controversy (‫ )ﺟدال‬in the Combination of Antipseudomonal drugs :
for Patients with S. aureus infection . 1. -antipseudomonal Beta-lactam with an Aminoglycoside.(Synergy but potential nephrotoxicity.)

2. -antipseudomonal Beta-lactam with a Fluoroquinolone.(no synergy but reduced nephrotoxicity)

Response to the therapy
If no clinical response is noted or deterioration occurs, we need to consider:

Infectious causes:
● Resistant pathogen
● Superinfection
● Unusual pathogens
● Lung abscess
● Extrapulmonary infection

Noninfectious events:
● Heart: congestive heart failure (CHF)

● Lung: fibroproliferative acute respiratory distress syndrome

(ARDS), pulmonary emboli, Atelectesis.
Quiz :
1)For severe HAP in which infection with resistant organisms is likely , What is the appropriate therapy
must be applied to the patient?

A.surgery B.combination therapy C.monotherapy

2) To treat pneumonia we initially use

A.Narrow spectrum B.Broad spectrum C.Neither, wait for the result of the culture
antibiotic antibiotic

Answers : 1-B 2-B 3-C 4-A 5-B

3) Which of the following can cause pneumonia to patient who had Received corticosteroids

A.Anaerobes B.MSSA C.MRSA

4)The common causes of late-onset pneumonia, particularly in ventilated patients are

A. P. aeruginosa and B. S. Aureus C.Anaerobes

Acinetobacter

5) a patient had been admitted to the hospital, and after 12h He developed a symptoms for pneumonia
,what is the most likely type of pneumonia he had .

A.HAP B. CAP C.VAP

SAQ Answers
1-Name the organism which can cause health care associated
pneumonia (HCAP)?

2-What is the difference between the duration of early and late 1. Pseudomonas aeruginosa
onset of nosocomial pneumonia? 2. Early onset occurs in the first 4
days, late onset in more than 4 days.
3-List two important processes required for pathogenesis of VAP. 3. Bacterial colonization of the
aerodigestive tract, and Aspiration of
4-How can we prevent VAP?
contaminated secretion into the Lower
5-There are three factors may be influenced the pathogen, mention airway. 4. By topical Gentamicin,
them. Colistin, Vancomycin cream given
every 6h for 3 weeks
6-If a patient with kidney problems has pneumonia, what is the 5. coexisting illnesses, prior treatment,
preferable drug we can use? and length of hospitalization.
6. Linezolid
7-If a patient was in the ICU on a ventilator and he has head trauma or
neurosurgery (for example they had brain tumor 7. S. aureus .
and went through a surgery) with gram positive cocci in cluster. What is 8. Fever, abnormal chest x-ray and
the most likely causative agent? vital signs are decreased.
9. Linezolid, because it has less
8-What are the symptoms of Pneumonia? toxicity which means there will be less
kidney damage.
9-A patient with HAP growing MRSA what is the drug of choice?
Why?
 Team Leaders

Badr AlQarni Renad AlMutawa

Team Sub-Leader
T
Abdullah Alassaf
This lecture is done by:

Team Members

Boys Girls

★ Faisal Alkoblan ★ Noura Almazrou

★ Faris Almubarak ★ Rema Almutawa
★ Alwaleed Alazmi ★ Elaf Almusahel
★ Mohammed Alshoieer ★ Lina Alosaimi
★ abdullah Alothman ★ Ghada Alsadhan Contact us:
★ Faisal Alzahrani ★ Sarah Alhelal
★ Abdullah Alzamil ★ Amirah Alzahrani
★ Rawan Alzayed
★ Sarah Alkhalife
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