Gram Negative Bacilli I-II (2) IGNORE

Gram-negative

a. they are always…

b. basically never…

a. usually rods

b. Cocci are basically never gram-negative

• Exception: Neisseria

Give me big names we will cover

1.  HAEMOPHILUS INFLUENZAE

2. HACEK GROUP

3. PASTEURELLA MULTOCIDA

4. FRANCISELLA TULARENSIS (TULAREMIA)

5. BRUCELLA (BRUCELLOSIS)

6. LEGIONELLA

7. BORDETELLA PERTUSSIS (WHOOPING COUGH)

8. VIBRIO

• CHOLERAE

• PARAHAEMOLYTICUS

1. CAMPYLOBACTER

2. HELICOBACTER PYLORI

HAEMOPHILUS INFLUENZAE

main points covered

Identification

MAIN VIRULENCE FACTOR

Diseases

Exam Pearl

HAEMOPHILUS INFLUENZAE

Identification

• Gram-negative coccobacillus (short rod)

• Fastidious (needs rich media)

• Facultative

HAEMOPHILUS INFLUENZAE

MAIN VIRULENCE FACTOR

• Capsule

  • Prevents phagocytosis

  • Vaccine targets capsule

HAEMOPHILUS INFLUENZAE

Diseases

• Meningitis

• Sinusitis

• Otitis media (kids)

• Sepsis

HAEMOPHILUS INFLUENZAE

Exam Pearl

• Kids → short Eustachian tube → ↑ ear infections

• Spread: person-to-person (URT colonizer)

HACEK GROUP

main points covered

• ID

• Cause

HACEK GROUP

• ID

• Cause

• Live: Fastidious oral/URT flora

• Cause native valve endocarditis

PASTEURELLA MULTOCIDA

main points covered

• ID

• Source

• Disease

 PASTEURELLA MULTOCIDA

• ID:

• Source:

• Disease:

• ID: Small gram-negative coccobacillus

• Source: Cat/dog bites or scratches

• Disease: Soft tissue infection

FRANCISELLA TULARENSIS (Tularemia)

main topics covered

ID

Source

Disease

FRANCISELLA TULARENSIS (Tularemia)

ID

Source

Disease

ID:

• Fastidious

• Can be severe

Source: Rabbits, rodents, ticks

Disease:

• Fever

• Ulcer + lymph node swelling

• Can cause pneumonia

BRUCELLA

main topics covered

• ID

• Sources

• Classic Sign

• Complications

BRUCELLA

• ID

• Facultative intracellular

  • Survives inside host cells

BRUCELLA

Sources

• Unpasteurized dairy

• Undercooked meat

BRUCELLA

Classic Sign

Undulating fever

BRUCELLA

Complications

• Endocarditis

• Osteomyelitis

LEGIONELLA

main topics covered

• ID

• sources

• diseases

• risk factors

• diagnosis

LEGIONELLA

ID

• Intracellular survival in macrophages

LEGIONELLA

Source

• Water systems

• Aerosol inhalation (AC units, cooling towers)

LEGIONELLA

Disease

• Causes severe pneumonia

LEGIONELLA

Risk Factors

• Smoking

• Chronic lung disease

• Immunocompromised

LEGIONELLA

Diagnosis

• PCR commonly used

 

BORDETELLA PERTUSSIS

main topics covered

• general facts

• 3 stages

• important treatment

BORDETELLA PERTUSSIS

• general facts

• aka whooping cough

• Humans only reservoir

• Aerosol spread

• Highly contagious (>90%)

BORDETELLA PERTUSSIS

 3 STAGES

1. Catarrhal (cold-like)

2. Paroxysmal (whooping cough)

3. Convalescent (slow recovery)

BORDETELLA PERTUSSIS

Important treatment

• PCR = test of choice

• Antibiotics most effective early

• Less effective in later stages

• Vaccine prevents disease

VIBRIO CHOLERAE

main topics covered

• ID

• class signs

• virulence

• risk factors

• treatment

VIBRIO CHOLERAE

• ID

• Curved gram-negative rod

• Motile

VIBRIO CHOLERAE

CLASSIC signs

• Rice-water diarrhea

• Severe dehydration

• Electrolyte imbalance

VIBRIO CHOLERAE

VIRULENCE

• Pili attachment

• Cholera toxin → massive fluid secretion

VIBRIO CHOLERAE

Risk Factors

• Contaminated water

• Poor sanitation

• Reduced gastric acidity increases risk

• Large inoculum usually required

VIBRIO CHOLERAE

 TREATMENT

• Rehydration FIRST

• Then antibiotics if needed

VIBRIO PARAHAEMOLYTICUS

topics covered

• ID

• source

• disease

VIBRIO PARAHAEMOLYTICUS

• ID -

• Source:

• Disease:

• ID - Halophilic (salt tolerant)

• Source: Seafood

• Disease: Gastroenteritis

CAMPYLOBACTER JEJUNI

topics covered

• ID

• source

• diseases

CAMPYLOBACTER JEJUNI

• ID

• Curved/spiral shaped

• Motile

CAMPYLOBACTER JEJUNI

source

• Animal exposure/contaminated food

• Requires fairly large inoculum

CAMPYLOBACTER JEJUNI

• diseases

• Causes diarrhea (usually self-limited)

• Rare complication: Guillain–Barré syndrome

HELICOBACTER PYLORI

topics covered

• key enzyme

• diseases

• diagnosis

• treatment

HELICOBACTER PYLORI

key enzyme

• Urease

  • Breaks down urea

  • Basis of breath test

HELICOBACTER PYLORI

diseases

• Causes gastritis

• Causes peptic ulcers

• Associated with gastric cancer

HELICOBACTER PYLORI

Diagnosis

• Endoscopy + biopsy

• Breath test

HELICOBACTER PYLORI

treatment

PPI + antibiotics