Normal Flora, Epidemiology, Disease Transmission

Question 1

What, when, and where is the “first” bacteria newborns contact with?

Answer 1

Lactobacilli from mothers vagina (at birth)

Question 2

Where can you find the following bacterial flora in our bodies?

• Streptococcus species
• Bacteroides fragilis
• Lactobacilli
• Staphylococcus epidermidis

Answer 2

Respiratory: Streptococcus species (mainly alpha hemolytic)
GI: Bacteroides fragilis
Vagina: Lactobacilli
Skin: Staphylococcus epidermidis

Question 3

What’s a transient microbiota?

Answer 3

• Microorganisms that are present “temporarily”
• can be pathogenic or nonpathogenic
• can be removed by handwashing

Question 4

How do pathogens produce disease?

Answer 4

adhere + penetrate or release toxins

Question 5

Why is normal flora important?

Answer 5

competition for nutrients and affecting environmental factors (e.g. pH, O2), which prevent overgrowth of harmful microorganisms

Question 6

Differences between primary and opportunistic pathogen

Answer 6

Primary: always cause disease (never normal flora)
Opportunistic: may cause disease under certain circumstances (can be normal flora)

Question 7

Vaginal flora maintains a pH of?

Answer 7

3.5-4.5, which inhibits overgrowth of Candida Albicans

Question 8

In Intestine, E. Coli produce?

Answer 8

Bacteriocins, which inhibit growth of closely related bacteria

Question 9

C. difficile is inhibited by?

Answer 9

Normal Intestinal Flora (broad spectrum antibiotics reduces them)

Question 10

Bacillus anthracis

1. Grain stain characteristics?
2. Where is it found?
3. What disease does it cause?

Answer 10

1. Gram positive bacillus with hardy spores
2. Soil and on vegetation
3. Anthrax (disease of herbivores)

Question 11

Why is B. anthracis threatening? (2 reasons)

Answer 11

• capsule is antiphagocytic

- spores can germinate into vegetative cells

Question 12

What are three routes of infection for B. anthracis?

Answer 12

Inoculation, inhalation, ingestion

*No human to human transmission

Question 13

What are the 3 components of toxin for B. anthracis?

Answer 13

protective antigen (PA)
Lethal factor (LF)
Edema factor (EF)

*must have PA and either LF or EF for toxicity

Question 14

What are human and animal vaccines of B. anthracis based on? Are they effective?

Answer 14

Human vaccine: capsule, poor antigenicity; no good

Animal vaccine: attenuated organisms/toxins; good

Question 15

What are the two major virulence factors of Bacillus anthracis?

Answer 15

Toxins (pX01) and capsule (pX02)

Question 16

What is the first eradication of an infectious disease? What kind of virus is that?

Answer 16

Smallpox; enveloped DNA virus

Question 17

Vaccinia and Variola virus differ in only ____ and ___.

Answer 17

one antigen/ cross react

Question 18

What are the three types of transmission of smallpox?

Answer 18

droplet (mucous membranes in upper respiratory tract) /direct /indirect

Question 19

What are the two complications of smallpox talked in class?

Answer 19

1. secondary infection with bacteria on the skin

2. lead to bacteremia, sepsis, or death

Question 20

Is there aymptomatic carriers and animal reservior for smallpox? Any good drug?

Answer 20

NO; no good drug

Question 21

What is zoonosis?

Answer 21

Tramission between animals (diseased or healthy carrier) and human (accidental host)

Question 22

The course of infectious disease can be broken down into 5 specific periods.

Answer 22

• incubation period
• prodromal period (mild symptoms)
• period of illness
• period of decline
• period of convalescence (no symptoms, but may continue to be a source of infection to others)

Question 23

What are two general types of transmission? Describe.

Answer 23

Horizontal: one person to another through conact, ingestion, vector.
Vertical: pregnant woman to feus

Question 24

What are the 2 vector transmission? Describe.

Answer 24

Mechanical: pathogen on the outside of their bodies
Biological: pathogen in their body

Question 25

What are the 3 contact transmission? Describe.

Answer 25

direct: person to person (eg. touch)
indrect: person & non-living object (eg. towel)
droplet: mucus droplet (eg. sneeze)

Question 26

What is vehicle transmission?

Answer 26

transmission through a contaminated source (eg. food, water, blood)

Question 27

What is epidemiology and its purpose?

Answer 27

The study of when and where diseases occur to control disease transmission

Question 28

What is the difference between incidence and prevalence?

Answer 28

incidence: number of diseases occuring WITHIN A SPECIFIED TIME PERIOD
prevalence: number of diseases in the POPULATION at a POINT IN TIME

Question 29

What is the difference beween morbidity and mortality?

Answer 29

morbidity: incidence of specific diseases
mortality: number of deaths from diseases

Question 30

What are notifiable diseases?

Answer 30

Diseases required to report to Public Health

Question 31

What cells are predominantly presented in Acute and Chronic Disease?

Answer 31

Acute: Neutrophil
Chronic: mononuclear cells

Question 32

What are the difference between acute, chronic, sub-acute, and latent disease?

Answer 32

Acute: pus production
chronic: slower, development of granulomas
sub-acute: long time to develop fully
latent: dormant for long time before reactivation

Question 33

What is the most common nosocomial infection?

Answer 33

urinary tract

Question 34

Define the following:
Local infection
Systemic infection 
Focal infection
Primary infection
Secondary infection

Answer 34

Local infection: infection at one site
Systemic infection: infection spread through the body
Focal infection: stay in specific areas after systemic infection
Primary infection: initial infection
Secondary infection: complication of a primary infection

Question 35

What are the general sources of nosocomial infection? (5)

Answer 35

other patients
environment
healthcare professionals
patients' own normal flora
visitors

Question 36

Ways to avoid infection (4)

Answer 36

• Hand washing (most important) and hygienic routines
• Gloves, gowns, masks, goggles
• Proper handling of used needles
• Disinfection of the environment

Question 37

What are the sources of nosocomial infection to healthcare workers? (4)

Answer 37

• infected patients
• soiled bedding, towels, dressings, other fomites
• contaminated needles
• surgical equipment

Question 38

What to do if you accidentally get contaminated?

Answer 38

wash, flush, irrigate, report to supervisor, seek medical attention

(Eg. treat with anti-retroviral therapy for HIV, inject vaccination and treat with immunoglobulin therapy for Hepatitis)

Question 39

Consequences of nosocomial infection (4)

Answer 39

serious illness/death
prolonged hospital stay
expensive antimicrobials
patient becomes a carrier/source and spreads

Question 40

Define: 
Bacteremia
Septicemia
Toxemia
Viremia
Fungemia
Parasitemia

Answer 40

Bacteremia: bacteria in the blood
Septicemia: multiplying bacteria in the blood 
Toxemia: toxins in the blood
Viremia: viruses in the blood
Fungemia: fungi in the blood
Parasitemia: parasites in the blood

Question 41

The most ideal drug treatment for B. anthracis?

Answer 41

Penecillin (must start early)

Others: cipro, tetra, macrolides, clinda, chloro

Question 42

How can a variola major be presented? (3)

Answer 42

Ordinary
Modified/mild
Flat/hemorrhagic

Question 43

What are two forms of smallpox?

Answer 43

Variola major and minor