Normal Flora, Epidemiology, Disease Transmission Flashcards
What, when, and where is the “first” bacteria newborns contact with?
Lactobacilli from mothers vagina (at birth)
Where can you find the following bacterial flora in our bodies?
- Streptococcus species
- Bacteroides fragilis
- Lactobacilli
- Staphylococcus epidermidis
Respiratory: Streptococcus species (mainly alpha hemolytic)
GI: Bacteroides fragilis
Vagina: Lactobacilli
Skin: Staphylococcus epidermidis
What’s a transient microbiota?
- Microorganisms that are present “temporarily”
- can be pathogenic or nonpathogenic
- can be removed by handwashing
How do pathogens produce disease?
adhere + penetrate or release toxins
Why is normal flora important?
competition for nutrients and affecting environmental factors (e.g. pH, O2), which prevent overgrowth of harmful microorganisms
Differences between primary and opportunistic pathogen
Primary: always cause disease (never normal flora)
Opportunistic: may cause disease under certain circumstances (can be normal flora)
Vaginal flora maintains a pH of?
3.5-4.5, which inhibits overgrowth of Candida Albicans
In Intestine, E. Coli produce?
Bacteriocins, which inhibit growth of closely related bacteria
C. difficile is inhibited by?
Normal Intestinal Flora (broad spectrum antibiotics reduces them)
Bacillus anthracis
- Grain stain characteristics?
- Where is it found?
- What disease does it cause?
- Gram positive bacillus with hardy spores
- Soil and on vegetation
- Anthrax (disease of herbivores)
Why is B. anthracis threatening? (2 reasons)
- capsule is antiphagocytic
- spores can germinate into vegetative cells
What are three routes of infection for B. anthracis?
Inoculation, inhalation, ingestion
*No human to human transmission
What are the 3 components of toxin for B. anthracis?
protective antigen (PA) Lethal factor (LF) Edema factor (EF)
*must have PA and either LF or EF for toxicity
What are human and animal vaccines of B. anthracis based on? Are they effective?
Human vaccine: capsule, poor antigenicity; no good
Animal vaccine: attenuated organisms/toxins; good
What are the two major virulence factors of Bacillus anthracis?
Toxins (pX01) and capsule (pX02)
What is the first eradication of an infectious disease? What kind of virus is that?
Smallpox; enveloped DNA virus
Vaccinia and Variola virus differ in only ____ and ___.
one antigen/ cross react
What are the three types of transmission of smallpox?
droplet (mucous membranes in upper respiratory tract) /direct /indirect
What are the two complications of smallpox talked in class?
- secondary infection with bacteria on the skin
2. lead to bacteremia, sepsis, or death
Is there aymptomatic carriers and animal reservior for smallpox? Any good drug?
NO; no good drug
What is zoonosis?
Tramission between animals (diseased or healthy carrier) and human (accidental host)
The course of infectious disease can be broken down into 5 specific periods.
- 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)
What are two general types of transmission? Describe.
Horizontal: one person to another through conact, ingestion, vector.
Vertical: pregnant woman to feus
What are the 2 vector transmission? Describe.
Mechanical: pathogen on the outside of their bodies
Biological: pathogen in their body
What are the 3 contact transmission? Describe.
direct: person to person (eg. touch)
indrect: person & non-living object (eg. towel)
droplet: mucus droplet (eg. sneeze)
What is vehicle transmission?
transmission through a contaminated source (eg. food, water, blood)
What is epidemiology and its purpose?
The study of when and where diseases occur to control disease transmission
What is the difference between incidence and prevalence?
incidence: number of diseases occuring WITHIN A SPECIFIED TIME PERIOD
prevalence: number of diseases in the POPULATION at a POINT IN TIME
What is the difference beween morbidity and mortality?
morbidity: incidence of specific diseases
mortality: number of deaths from diseases
What are notifiable diseases?
Diseases required to report to Public Health
What cells are predominantly presented in Acute and Chronic Disease?
Acute: Neutrophil
Chronic: mononuclear cells
What are the difference between acute, chronic, sub-acute, and latent disease?
Acute: pus production
chronic: slower, development of granulomas
sub-acute: long time to develop fully
latent: dormant for long time before reactivation
What is the most common nosocomial infection?
urinary tract
Define the following: Local infection Systemic infection Focal infection Primary infection Secondary infection
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
What are the general sources of nosocomial infection? (5)
other patients environment healthcare professionals patients' own normal flora visitors
Ways to avoid infection (4)
- Hand washing (most important) and hygienic routines
- Gloves, gowns, masks, goggles
- Proper handling of used needles
- Disinfection of the environment
What are the sources of nosocomial infection to healthcare workers? (4)
- infected patients
- soiled bedding, towels, dressings, other fomites
- contaminated needles
- surgical equipment
What to do if you accidentally get contaminated?
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)
Consequences of nosocomial infection (4)
serious illness/death
prolonged hospital stay
expensive antimicrobials
patient becomes a carrier/source and spreads
Define: Bacteremia Septicemia Toxemia Viremia Fungemia Parasitemia
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
The most ideal drug treatment for B. anthracis?
Penecillin (must start early)
Others: cipro, tetra, macrolides, clinda, chloro
How can a variola major be presented? (3)
Ordinary
Modified/mild
Flat/hemorrhagic
What are two forms of smallpox?
Variola major and minor
