Ch 13 Flashcards
normal flora
colonists
transients
rapidly lost from the body
infection
condition in which pathogenic microbes penetrarte the host defenses, enter the tissues and multiply
disease
when the effects of the infection damage or disrupt tissue
-any deviation from health
infectious diseases
disruption of tissue or organ due to microbes
pathogens
avoid host defenses, infiltrate body and cause infection
virulence
ability to invade a host and produce toxins
Pathologic
disease state caused by structural and functional damage to tissues
Entrenchment
infectious agent is not arrested by immune system and is entrenched in tissues where pathologic effects cause damage
carrier state
microbe is harbored without effects
Morbidity
state of diseased
indigenous flora
normal resident flora that inhabit the body
What areas of the body are sterile?
organs, fluids, and CNS
Overgrowth of what two normal flora bacteria occurs during antibiotic treatment?
1) Clost. difficile
2) Candida albicans
What bacteria act as opportunist pathogens?
Pneumococcal and pneumocystis pneumonia
Flora may act as a reservoir for bacterial pathogens such as?
1) staph. aureus
2) corynebacterium diphtheriae
3) Neiss. meningitidis
When does baby first come into contact with microbes?
When fetal membrane of mother breaks
Within 8-12 hours after birth what bacteria have colonized newborn?
1) streptococci
2) staph.
3) lactobacilli
Bacteria from breast feeding?
bifidobacterium, which metabolizes sugars into acids that protect the infant from infection
What events cause flora to be established?
eruption of teeth, weaning, solid food
Where are microbes found on skin
Epidermis-dead cells
not in dermis or subcutaneous
Transition zones
where skin joins with mucous membranes. Contain rich flora
transient population
aka exposed flora
clings to skin surface but does not grow
-influenced by hygiene
resident population
lives and multiplies in deeper layers of the epidermis and glands and follicles
Normal skin resident examples
1) staph.
2) corynebacterium
3) propionibacterium
4) yeasts
What are prominent in sebaceous secretions
1) lipophilic mycobacteria
2) staph.
What is prominent in smegma
mycobacterium smegmatis
Only places internally that have permanent flora
oral cavity, large intestine, and rectum
Common residents of mouth
Streptococcus species:
1) S. sanguis
2) S. salivarius
3) S. mitis
Responsible for dental caries?
1) S. mutans
2) S. sanguis
by forming sticky dextran slime layers in the presence of sugar which attracts more bacteria
Fecal flora
Anaerobic bacteria:
1) bacteroides
2) bifidobacterium
3) fusobacterium
4) clostridium
Coliforms
gram- facultative anaerobes and lactose fermenting microbes found in smaller numbers in feces
- may ferment waste materials into vitamins
1) E. coli
2) Enterobacter
3) Citrobacter
skatole
a chemical that gives feces its characteristic stench
What resides in nasal cavity?
staph aureus
What resides in mucous membranes of nasopharynx?
Neisseria species
What resides in tonsils and lower pharynx?
streptococci and haemophilus
Residents of urethra?
nonhemolytic strep., staph., coryn. and occasionally coliforms
What does estrogen effect with respect to microbes?
Estrogen causes secretion of glycogen which lactobacillus ferment and lower the pH, which protects a fetus against other microbes
-prepuberty and postmenopause have little estrogen and allow a mixed flora to exist in the vagina
diptheroids
non-pathogenic species of corynebacterium
axenic
germ free
gnotobiotic studies
testing the effect of a single microbe in a sterile environment
-means known origin
Entamoeba histolytica
more pathogenic in non-germ free animal b/c it feeds on normal flora in intestine
true pathogens
aka primary pathogens cause disease in healthy individuals
Opportunistic pathogens
causes disease only when host is compromised or establish in an area that they normally don’t
Portal of entry
usually cutaneous or membranous boundary where infectious agent enters
-most pathogens have a specific portal of entry and a wrong portal will not cause infection
exogenous
originating from source outside body
endogenous
already existing on or in body
Examples with multiple portals of entry
1) Myco. TB-resp. and GI tract
2) Coryn. dipth.-throat and skin
3) strep. and staph. have several portals
Examples that enter through broken skin
1) S. aureus-boils
2) Strept. pyogenes-impetigo
3) fungal dermatophytes
4) gangrene
5) tetanus
Pathogens of the eye
target conjunctiva: 1)haemophilus aegyptius-pinkeye 2)chlamydia trachomatis-trachoma 3)Neisseria gonorrhoeae after injury or foreign objects: 4)herpes 5)acanthamoeba-contaminates homemade contact solutions
GI pathogens
gram neg rods: 1)salmonella 2)shigella 3)vibrio viruses: 4)poliovirus 5) hep A 6)echovirus 7)rotavirus protozoans: 8)entamoeba histolytica 9) giardia lamblia
pneumonia
inflammatory condition of the lung that can be caused by many microbes
Agents of lung disease
1) mycobacterium TB
2) histoplasma (fungus)
Diseases that can cross placenta/significant during childbirth
STORCH
1) Syphilis
2) Toxoplasmosis
3) Others (hep B, AIDS, chlamydia)
4) Rubella
5) Cytomegalovirus
6) Herpes
Infectious dose (ID)
or microbes necessary for infection
relationship b/w virulence and ID
lower ID=more virulent
Adhesion
process by which organisms gain a stable foothold at portal of entry
How to bacteria adhere?
fimbrae, flagella, slimes, or capsules
How do viruses adhere?
specialized receptors
How do protozoa adhere?
infiltrate by organelle of locomtion
Mucinase
digests protective coating on mucous membranes
-amebic dysentery
Keratinase
digests keratin
-secreted by fungi that causes ringworm
collagenase
digests collagen-fiber of connective tissue
-invasive factor of worms and clostridium
hyaluronidase
digests hyaluronic acid-cements animal cells together
-viruluence factor for staphy., clost., strep, and pneumococci
coagulase
causes blood to coagulate
-by pathogenic staph.
streptokinase (streptase) and staphylokinase
dissolve blood clots
toxin
chemical product of organisms that is poisonous to other animals
toxinogenicity
power to produce toxins
toxinoses
diseases caused by toxins