EXAM 2 Medical Micro Review Intro Flashcards
Nonpathogenic microorganisms adapted to grow on body surfaces of the host, forming part of the normal flora
Commensals (Colonizers)
What are commensals?
nonpathogenic (don’t cause disease) organisms that grow normally on our body, help in many ways
what body surfaces are Commensals (Colonizers)
found on
Skin
Mucous membranes
Commensals (Colonizers) examples of mutualistic relationship (4)
Digestive aids
Prevents excessive overgrowth of dangerous bacteria
Maintains protective acid pH of natural barriers
Synthesis of essential metabolites
Microorganisms that do not usually produce disease in healthy individuals, but are implicated in human infections when the host is weakened or compromised
Opportunists
what are opportunists?
don’t typically cause disease in healthy patients but can cause disease when patients immune status becomes compromised
example of when commensals cause infection
when antibiotics cause change in normal flora concentrations (yeast infection would be an example)
opportunists that are Transient visitors of the respiratory tract (5)
Strep pneumoniae,
Group A Strep,
Neisseria meningitidis, Haemophilus influenzae, Klebsiella pneumoniae
opportunists that are Normal residents of the GI tract (3)
Escherichia coli,
Klebsiella pneumoniae, Citrobacter freundii
Microorganisms that can produce disease or tissue damage by their mere presence regardless of the condition of the host
True Pathogens
what are true pathogens?
can cause disease in anyone- healthy or unhealthy
examples of true pathogens? (5)
Staphylococcus aureus Salmonella enterica Typhi, S. Enteriditis Treponema pallidum Mycobacterium tuberculosis Shigella
5 examples of bacteria that are Infectious diseases in human transmitted from animals
- Yersinia pestis- pneumonic plague
- Francisella tularensis:
- Vibrio cholerae - Cholera
- T. pallidum- Syphilis
- Variola -Smallpox or Polio virus
how is Yersinia pestis transmitted to humans
from rodents to fleas to humans
what bacteria causes the pneumonic plague
Yersinia pestis
how is Francisella tularensis transmitted to humans
Insects to animals which contaminates man handling animal carcass
(hunters are an example)
HOW IS Vibrio cholerae spread?
GI disease spread through consumption of contaminated water
Factors Accounting for the Virulence of Bacteria (7)
Capsules – (Antiphagocytic) Spores High lipid content in cell wall Pili Exotoxins Enzymes Endotoxins (Lipopolysaccharide)
Two Major Types of Immunity
innate immunity
adaptive immunity
immunity type that is Natural Barriers to microbial invasion
Innate immunity
immunity type that is Always present (do not require previous encounter with microbe)
Innate immunity
innate immunity has what kind of defenses?
External natural defenses include mechanical, chemical, and biological barriers
how is the response time in innate immunity?
minutes to hours
innate immunity components
Phagocytic cells (monocytes, PMN’s) agglutinins (clumping) activated complement (opsonization) cytokines (protein messengers which limit microbial growth) reticuloendothelial system (filter)
type of immunity that has “Tailored response” to invading microbe
Adaptive immunity
how is the response time in adaptive immunity?
Initial response slow (week or more to develop)
hallmarks of Adaptive immunity
specificity and memory
2 agranulocytes
Lymphocytes
Monocytes
3 Granulocytes
Neutrophils
Basophils response
Eosinophils
neutrophils are associated with?
bacterial infections
if a bacteria is more virulent, what does that mean?
more potential to cause infection
basophils are associated with?
allergy/antigen response
Eosinophils are associated with?
viral/parasitic infection and allergic response
Lymphocytes
associated with antibody response
B lymphocytes
Lymphocytes
associated with recognizing non-self via antigen and major histocompatibility complex (MHC), Natural killer cells
T lymphocytes
monocytes can differentiate into
phagocytes
response time of monocytes
fast
the body’s primary defense against bacterial infection.
Neutrophils (WBC’s)
Segmented neutrophils are what form?
mature
Banded neutrophils are what form?
immature
what test Shows us band vs segmented amounts of neutrophils?
CBC (complete blood count) with differential
what is left shift?
means an increase in the relative number of immature forms of neutrophils (>10%)
what is left shift a clinical marker of?
Clinical marker of acute inflammation/ infection
So is “left shift” always a sign of disease?
no, not always infections, can be secondary inflammatory response
hose defenses in skin
Acid pH from normal flora and sebaceous gland secretions
hose defenses in Mucous membranes
Mucus (moistens and protects)
Lysozymes
Secretory antibodies (IgA)
hose defenses in Respiratory tract
Cilary action move particles out of the lung
Cough reflex
Mucous membranes protective factors
hose defenses in Gastrointestinal tract
Peristalsis -> movement of contents
Saliva
Stomach acid
Proteolytic digestive enzymes
Lysozymes and Secretory IgA
hose defenses in Genitourinary tract
Urine production provides flushing of microbes
Vaginal pH (acidic)
Mucous membranes
hose defenses in blood
WBC’s
antibodies (IgG, IgM)
complement
Reticuloendothelial system
Migrating RES (monocytes and macrophages) Sessile RES (Kupffer cells and spleen)
Most Useful Nomenclature
for Classification of Bacteria (3)
Gram Stain
Shape and configuration
Growth requirements
the following bacteria are examples of what type of bacteria?
Mycobacterium tuberculosis Mycoplasma pneumoniae Ureaplasma spp. Chlamydia pneumoniae and Chlamydia trachomatis Legionella pneumophila
atypical
bacteria that don’t, or are difficult to stain and often require special culture media
atypical
important characteristic of gram positive bacteria
thick peptidoglycan layer
important characteristics of gram negative bacteria
thin peptidoglycan layer and an outer membrane that contains lipopolysaccharide, phospholipids, and proteins
does gram positive bacteria hold a gram stain?
yes
does gram negative bacteria hold a gram stain?
no
why do gram negative bacteria not hold a gram stain?
thin peptidoglycan layer
when Beta lactamase breaks down antibiotics this causes _____.
resistance
Why do we care about all these differences between types of organisms?
because we need to classify and identify organisms so we can use appropriate antibiotics
How do we determine what organism is potentially causing disease? (3)
Symptoms/Physical Exam
Environment of patient
Tests
3 characteristics of gram stain
Informative (stain and morphology)
Rapid
Cheap
