1. Other Pathogenic Gram-Negative Rods20
Other Pathogenic Gram-Negative Rods

2. Other Pathogenic Gram Negative Rods
The Pasteurellaceae
Most are small, nonmotile, facultative anaerobes
Require heme or cytochromes for growth
Two genera contain most human pathogens of this family
Pasteurella
Haemophilus

3. Pasteurella multocida
Normal microbiota of oral and nasopharyx of domestic cats and dogs
Human infection via animal bites
Causes localized swelling of lymph nodes
Treat with antibiotics

4. Bartonella Bartonella henselae Cat-scratch disease
Transmitted through cat scratches and bites
Causes fever, malaise, and swelling at infection site
Bartonella infections are treated with various antimicrobials

5. Haemophilus influenzae
Most strains have capsule that resists phagocytosis
H. influenzae type b is most significant strain
Common cause of meningitis prior to vaccination
Hib vaccine has eliminated most disease by H. influenzae in the United States
Other H. influenzae strains cause a variety of diseases
Conjunctivitis, sinusitis, dental abscesses, meningitis
Figure 20.19

6. Bordetella pertussis Small, aerobic, nonmotile coccobacillus Disease:
Pertussis (whooping cough)
Most cases of disease are in children
Virulence factors
Adhesins and toxins mediate the disease
Pertussis toxin
Adenylate cyclase toxin
Dermonecrotic toxin
Tracheal cytotoxin

7. Bordetella pertussis Transmission Symptoms http://youtu.be/RogpNWYeSQs
Bacteria inhaled in aerosols
Multiply in epithelial cells
Symptoms
Occurs in four stages
Severe “Whooping” cough symptoms

8. Progression of Pertussis
Figure 20.25

9. Bordetella pertussis Treatment Prevention Primarily supportive;
Antibiotics decrease number of bacteria but course of disease usually unaffected
Tracheal cells need time to regenerate
Prevention
DTaP at 6 weeks through 6 years
Tdap at 10 years through 64 years
Td after 7 years old at 10 years intervals

10. Legionella pneumophila
Description
Gram negative intracellular parasites
found in water sources
survives inside amoeba
Pathogenicity
resistant to phagocytosis
immunocomprommised host
Transmission
Inhale bacteria in aerosols from water sources
not transmitted from human to human

11. Legionella pneumophila
Symptoms:
Legionnaire’s Disease
days after exposure
high fever, dry cough, little sputum, SOB
Diagnosis:
chest X ray
culturing bacteria
Treatment:
Erythromycin
Chlorine and heat (water sources)

12. Pseudomonas aeruginosa
Description
Ubiquitous in soil, decaying organic matter, moist environments
Rarely part of normal human microbiota
Virulence factors
Fimbriae, adhesins, capsule, toxins, and enzymes
Despite producing various virulence factors rarely causes disease

13. Pseudomonas aeruginosa
Opportunistic infections
Can colonize almost any organ or system
Common in the lungs of cystic fibrosis patients
Biofilm protects bacteria from phagocytosis
Common in burn patients

14. Pseudomonas aeruginosa
Treatment
Fluoroquinolones, some aminoglycosides and beta-lactams; usually combination
Multiple drug resistance
ability to metabolize drugs
form biofilms
cell membrame pumps
Prevention

15. Acinetobacter baumannii
Description
Commonly found in soil and water
Very low risk of infection in healthy people
May “colonize” a patient without causing infection especially in tracheostomy sites or open wounds
Acinetobacter infections rarely occur outside of healthcare settings.

16. Acinetobacter baumannii
Transmission
Acinetobacter can be spread to susceptible persons by person-to-person contact or contact with contaminated surfaces
Outbreaks occur in hospitalized patients who have weakened immune systems, especially very ill patients on a ventilator, chronic lung disease, open wounds and those with a prolonged hospital stay

17. Routes of Transmission

18. Acinetobacter baumannii
Diseases
Causes a variety of diseases, ranging from pneumonia to serious blood or wound infections, and the symptoms vary depending on the disease. 
Acinetobacter infection can either cause or contribute to death in these patients.

19. Acinetobacter baumannii
Treatment
Multidrug resistant; CDC statistics from Iraqi War:
35% of isolates were only susceptible to Imipenem
4% were resistant to ALL DRUGS
Prevention
Careful attention to infection control procedures, such as hand hygiene and environmental cleaning, can reduce the risk of transmission