Gram Positive Non-Endospore Forming Infections

Question 1

Listeria monocytogenes

Answer 1

Meningitis (muscle/nervous)

Septicemia (lymph)

Diarrhea

Question 2

Corynebacterium diphtheriae

Answer 2

Diphtheria (skin/skeletal & respiratory)

Question 3

Mycobacterium tuberculosis

Answer 3

Recurrent tuberculosis (nervous/muscle)

Extrapulmonary tuberculosis (lymph)

Primary tuberculosis (respiratory)

Question 4

Mycobacterium leprae

Answer 4

Hansen’s disease (skin/skeletal)

Paucibillary Hansen’s disease (nervous/muscle)

Multibacillary Hansen’s disease (lymph)

Question 5

Listeria Characteristics

Answer 5

• no capsule
• no endospores
• flagella
• resistant to heat, cold, salt, extreme pH, bile
• intracellular pathogen to evade immune
  detection

Question 6

Listeriosis

Answer 6

Tm: ingestion of contaminated dairy, poultry, meat

3rd most common foodborne illness

primarily affects immunocompromised
pregnant women can pass it on to baby

fever, diarrhea, meningitis, septicemia
Tx: abx

Question 7

Diphtheria

Answer 7

Tm: close contact, respiratory droplets, fomites

Question 8

2 Types of Diphtheria

Answer 8

1. Respiratory diphtheria
   diphtheria toxin
   pseudomembrane
   death by asphyxiation
   toxemia causes myocarditis, muscle weakness,
   paralysis
   Tx: DTaP and Tdap vaccines; DAT
2. Cutaneous diphtheria
   secondary infection
   ulcers heal slowly

Question 9

Mycobacterium Characteristics

Answer 9

-acid-fast stain +
- mycolic acid, waxy cell wall
- generation time of several days
- resistant to drying, acids, and abx entry
- no capsule
- no flagella

Question 10

Tuberculosis

Answer 10

currently world’s #1 infectious killer

tubercle bacillus grows into strands called cords

cord factor: virulence and prevention of destruction by macrophages and lysosomes

Tm: respiratory droplets or mucus
risk factors: living in close quarters, poor nutrition and
medical care, immunocompromised
5-10% infected get TB; 85% of TB occurs in the lungs

Question 11

Primary TB

Answer 11

ID = 50 cells
bacilli are engulfed and multiply in alveolar
macrophages (asymptomatic)
1-3 weeks later: tubercles form, which confine
the bacteria, but may damage the lungs

Question 12

Recurrent TB

Answer 12

bacilli reactivate
violent coughing, green or bloody sputum, anorexia,
fatigue, chest pain
body wastes away

Question 13

Extrapulmonary TB

Answer 13

bacilli spread to and damage the lymph nodes,
kidneys, joints, brain, meninges
Tx: a combination of abx over 6-24 months, although MDR-TB and XDR-TB

Question 14

TB Detection

Answer 14

1. tuberculin test
2. chest X-ray
3. acid-fast stain of sputum or other specimen
4. cultural isolation and identification

Question 15

M.leprae

Answer 15

• strict parasite and can’t be grown in a lab
• slowest generation time
• the optimum temperature is 30oC

Question 16

Hansens Disease

Answer 16

Tm: prolonged contact, mechanical vector, respiratory droplets, armadillos
bacilli grow in macrophages, peripheral nerves, and skin

Question 17

Paucibacillary HD

Answer 17

flat, discolored skin lesions
sensory loss
easily treated

Question 18

Multibacillary HD

Answer 18

disfiguration over the body, esp. extremities
Tx: combination of abx for 12-24 months