Microbiology-Vaccine Preventable Bacterial Diseases of Childhood Flashcards Preview

Multisystems I > Microbiology-Vaccine Preventable Bacterial Diseases of Childhood > Flashcards

Flashcards in Microbiology-Vaccine Preventable Bacterial Diseases of Childhood Deck (22):
1

Passive immunization

Transfer of pre-formed antibody by IV Ig (TIG for tetanus) or antitoxin (botulism and diphtheria)

2

Active immunization

Stimulation of the host immune response by vaccination or natural infection and antibody formation.

3

Toxoid

Toxin preparation that stimulates formation of antitoxin

4

What type of vaccines are BCG for tuberculosis and Ty21A for typhoid?

Live, attenuated vaccines.

5

What type of vaccines are tetanus, diphtheria and anthrax?

Toxoid vaccines

6

What type of vaccines are the old pneumococcal 23 valent and meningococcal 4 valent?

Polysaccharide alone

7

What type of vaccines are Hib, the 13 valent pneumococcal and 4 valent meningococcal?

Conjugate

8

Why do children < 2 years of age need the conjugate pneumococcal vaccine?

Polysaccharides are T-independent antigens, which are not recognized by the immune system of children less than 2 years of age and you get mostly and IgM response. With the conjugate vaccine you activate T cells which produces IgG antibodies and memory plasma cells that results in lasting immunity.

9

Most likely population affected by bordetella pertussis

Children < 1 year old are at highest risk for whooping cough

10

A child presents with whooping cough. What would you expect lab results to look like?

Bordetella pertussis is a gram negative, pleomorphic, short coccobacilli that grow on Bordet-Gengou agar or Regan-Lowe charcoal medium with horse blood (isolate fatty acids b/c fatty acids are toxic to bordetella).

11

What are the virulence factors associated with bordetella pertussis?

Pertussis toxin (LPF): activates membrane and extracellular adenlylate cyclase via Gi protein -> increases cAMP -> fluid secretion in upper respiratory tract. Filamentous hemagglutinin: adhesion. Tracheal cytotoxin: looks like a fragmented cell wall and destroys ciliated epithelial cells.

12

Why might the lab be scared that someone has leukemia when they really have pertussis?

Bordetella pertussis causes an intense lymphocytosis.

13

Steps of pertussis infection

1) Colonization w/o invasion of respiratory epithelium (by filamentous hemagglutinin and pertactin 2) Local damage by tracheal cytotoxin 3) Impaired immune response by extracellular adenylate cyclase activation 4) Systemic lymphocytosis due to pertussis toxin

14

Difference between the old wholesale pertussis vaccine and the acellular vaccine?

The acellular vaccine prevents symptoms by neutralization of toxin, but not infection because there is no antibody response against the adhesins. The old vaccine prevents colonization.

15

Stages of pertussis

1) 7–10 day incubation w/no symptoms 2) 2-4 week catarrhal stage w/fever, malaise, runny nose 3) 2-4 week paroxysmal stage with whooping cough, vomiting and leukocytosis 4) 3-4 week convalescent stage with secondary complications like pneumonia, seizure and encephalopathy.

16

Why is it recommended for pregnant women to get the pertussis vaccine?

The effects of the vaccine wane by about 15 years of age

17

How do you treat a patient who comes in with active pertussis?

Erythromycin can be effective in the catarrhal and incubation stage. You may give it prophylactically to household contacts.

18

What type of disease is diphtheria?

Toxin-mediated disease. Diphtheria toxin has a binding subunit (B) and an active subunit (A) that ADP-ribosylates EF-2 and inhibits protein synthesis.

19

When will corynebacteria not cause diphtheria in the infected host?

When the lysogenic phage that encodes the toxin has not yet infected the bacterium

20

What vaccines do every infant and toddler get in the US?

DTap, HepB, Hib, IPV, MMR, Varicella, PCV, influenza, RV and HepA

21

For what diseases can we use passive therapy?

Botulism, tetanus and diphtheria

22

Lab characteristics of diphtheria

Gram positive, non-motile rods that form Chinese letters and catalase positive.