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58 terms

ID Exam 3

STUDY
PLAY
Most common bacterial pathogen for causing CAP
Streptococcus pneumoniae
Gram negative bacteria are more commonly associated with patients that have CAP requiring ICU inpatient treatment. True or False.
True
Assessment tools used for determining the site of care for CAP treatment (3)
1. Curb-65
2. Pneumonia Severity Index (PSI)
3. Discharge Stability Criteria
A new or progressive infiltrate on chest x-ray is required to make the diagnosis of pneumonia. True or False.
True
What are the respiratory fluoroquinolones? (3)
1. Gemifloxacin
2. Levofloxacin
3. Moxifloxacin
Z-Pack Coverage (Typical Organisms [4])
1. S. pneumoniae (23% Resistance)
2. H. influenzae
3. M. catarrhalis
4. S. auerus
Z-Pack Coverage (Atypical Organisms [3])
1. M. pneumoniae
2. C. pneumoniae
3. L. pneumophila
Mechanisms of Resistance of S. Pneumoniae (2)
Target Site Modification
1. B-Lactam Resistance (Altered PBPs)
2. Macrolide Resistance (Ribosomal Methylation)
Outpatient Empiric Therapy (Healthy and no use of antimicrobials within the previous 3 months)
Macrolide or Doxycycline
Outpatient Empiric Therapy (Comorbidities or use of antimicrobials within the previous 3 months)
B-Lactam PLUS Macrolide
OR
Fluoroquinolone
Three Indications Required for Diagnostic Testing
-ICU Admission
-Failure of Outpatient Therapy
-Pleural Effusion
Inpatient Treatment (Non-ICU)
B-Lactam (Cefotaxime, Ceftriaxone, Ampicillin) + Macrolide
OR
Respiratory Fluoroquinolone (Moxifloxacin, Gemifloxacin, Levofloxacin)
Inpatient Treatment (ICU)
B-Lactam + Azithromycin
OR
B-Lactam + Fluoroquinolone

If penicillin allergy, use respiratory fluoroquinolone or aztreonam
Inpatient Treatment (ICU plus Pseudomonas Infection)
Anti-pneumococcal, anti-pseudomonal B-lactam:
-Piperacillin-Tazobactam
-Cefepime
-Imipenem
-Meropenem
PLUS Ciprofloxacin or Levofloxacin
or PLUS Aminoglycoside and Azithromycin
or PLUS Aminoglycoside and Antipneumococcal Fluoroquinolone (e.g. Moxifloxacin or Levofloxacin)
Inpatient Treatment (ICU + CA MRSA)
Add vancomycin or linezolid to previous regimen.
Time to clinical response for treatment of CAP
3 days
Criteria for IV to PO switch (6)
1. Improvement in cough and dyspnea
2. Afebrile
3. Normal mental status
4. Heart rate/respiratory rate normalized
5. Stable blood pressure
6. Adequate PO Intake
Discharge Criteria (7)
1. Temperature <37.8C
2. Heart rate <100BPMs
3. Respiratory rate <24 Breaths/min
4. Systolic blood pressure GREATER than 90mmHg
5. Arterial Oxygen saturation >90%
6. Ability to maintain oral intake
7. Normal mental status
Duration of therapy
Minimum of 5 days or until:
-Afebrile for 2 to 3 days
-Max of one CAP-associated sign of clinical instability

Treat atypical infections for 10-21 days

Longer duration of treatment needed if initial empiric therapy was incorrect
Number of H. Influenzae Serotypes
Six (A-F)
Number of H. Influenzae Biotypes
Eight (I - VIII) determined by biochemical reactions:
Indole Production
Urease Activity
Ornithine Decarboxylase

**For epidemiologic purposes
Number of H. Influenzae Biogroups
Three biogroups
**For clinical purposes
H. Influenzae Serotype B Virulence Factor
Polyribitol Phosphate (PRP)
Treatment of Meningitis, Epiglottitis, or Septic Arthritis
Third Generation Cephalosporins
-Cefotaxime
-Ceftriaxone
Alternative
-Meropenem
-Chloramphenicol
H. Influenzae Morphology
-Motile - No
-Capsule - Yes (Virulent Factor)
L. Pneumophila Morphology
-Motile - Yes (Flagella)
-Capsule - No

**LPS is Major Antigen
Signs and Symptoms of Legionella Systemic Infection
Cardiac - Relative Bradycardia
Gastrointestinal - Watery diarrhea
Electrolyte - Hypophosphatemia
Temperature/Heart Rate Trend
Temperature increases 10bpm per degree Farenheit >102F
Relative Bradycardia
Heart rate does not increase in response to fever.
Must use caution using B-Blocker or Non-dihydropyridine CCBs
L. Pneumophila Culture
-Strict Aerobe
-High Moisture (Humidity) is necessary
-CO2 Enhancements (3-5%) is desirable
-Nutritionally fastidious
Treatment of L. Pneumophila Infection
Drugs of choice:
-Macrolides (Azithromycin or Clarithromycin)
-Fluoroquinolones (Ciprofloxacin or Levofloxacin)

Alternative:
-Tetracyclines (Doxycycline or Monocycline)
-Trimethoprim-sulfamethoxazole

**No B-Lactams because Legionella isolates produce B-Lactamases
Chlamydia
-Very small organisms
-Obligate intracellular parasites
Chlamydia Structure
-Lack a cell wall; Instead have a disulfide bond present in the outer membrane proteins forming a mesh or lattice of support
-Lack a peptidoglycan layer
-Small in comparison to other bacteria
Chlamydia Antigenic Structure
LPS - Antibodies develop against this antigen and it is also useful in serologic diagnosis
Chlamydia Growth Cycle
Two distinct forms:
1. Infectious Elementary Bodies (EB)
2. Noninfectious Reticulocyte Bodies (RB)
Treatment of Chlamydophila Pneumoniae
Drug of Choice:
Macrolides (Erythromycin, Clarithromycin, Azithromycin)
Tetracyclines (Tetracycline, Doxycycline)

Alternative:
Fluoroquinolone (Moxifloxacin)
Diseases caused by Chlamydophila psitacci
-Ornithosis/Psitticosis
Diseases caused by Chlamydophila trachomatis
-Trachoma
-Conjunctivitis
-Urogenital Infections
-LGV (Lymphogranuloma venerum)
Diseases caused by Mycoplasma pneumoniae
-Upper respiratory tract disease
-Atypical Pneumonia
-Tracheaobronchitis
-Extrapulmonary Manifestations (Rare)
M. pneumoniae Morphology and Physiology
-O2 requirement - Facultative anaerobe
-Cell Wall - No peptidoglycan making it insensitive to B-lactams, cephalosporins, or vancomycin
-Requires exogenous sterols for growth
-Colonies have "fried egg" appearance

**Major Antigenic Determinants: Glycolipids and Proteins
Mycoplasma pneumoniae Pneumonia
-Sometimes designated as Primary Atypical Pneumonia (PAP) or "Walking" Pneumonia
Treatment of Mycoplasma pneumoniae
Drug of Choice:
Macrolides (Erythromycin, Clarithromycin, Azithromycin)
Tetracycline (Tetracycline, Doxycycline)
Prophylaxis of Meningitis
-H. Influenzae
-N. Meningitidis
-Rifampin for H. Influenzae
-Rifampin or ciprofloxacin for N. meningitidis
Characteristics desirable in a drug used empirically to treat bacterial meningitis
Broad spectrum, lipophilic, and bactericidal
N. Gonorrhea Pili
Mediate attachment to nonciliated epithelial cells; Inhibit destruction by neutrophils
Por Proteins
Protect phagocyosed gonococci from intracellular killing via inhibition of phagolysome fusion
PorA
-Resistant to killing in serum
-Disseminated disease
PorB
Opa Proteins
Opacity proteins that facilitate gonococcal binding to epithelial cells and each other
Rmp Proteins
Reduction Modifiable Proteins
Stimulate production of antibodies that block serum bactericidal activity
Lipo-oligosaccharide (LOS)
Possess endotoxin activity stimulating inflammatory response (particularly TNF-alpha)
B-Lactamase
Catalyzes hydrolysis on B-Lactams such as penicillins
IgA1 Protease
Catalyzes degradation of secretory IgA
N. meningitidis Pili
Permit colonization in nasopharynx
Polysaccharide capsule
Protects meningococci from antibody-mediated phagocytosis
Colonization Factor (Aggregation Substance)
Ciliary-like protein found in cytoplasmic membrane
-Facilitates plasmid exchange
-Facilitates binding to epithelial cells
Colonization Factor (Carbohydrate Adhesin)
Multiple types found in individual enterococcal cells
-Facilitate binding to the host cell
Secretion Factor (Cytolysin)
Protein bacteriocin (Inhibits other bacteria)
-Facilitates colonization
-Inhibits growth of gram (+) Bacteria
-Promotes local tissue damage
Secretion Factor (Pheromone)
Neutrophil (PMN) Chemoattractant
-Regulates inflammatory reaction
Secretion Factor (Gelatinase)
Enzyme that catalyzes the hydrolysis of
-Gelatin
-Collagen
-Hemoglobin and other small peptides