Lecture 12 Normal Flora Flashcards
bacteria that permanently colonize host
normal microbiota
bacteria that may be present for days, weeks, or month
transient microbiota
Gram + bacteria are often found ____
on the skin
Gram - bacteria are often found ___
in the gut
the relationship between the normal microbiota and the host
symbiosis
commensalism
one organism benefits and the other is unaffected
ex. staph epidermidis
mutualism
both organisms benefit
ex. e coli in large intestine
parasitism
one organism benefits at the expense of the other
ex. H1N1 in host cell
superoorganisms
blend of host and microbial traits resulting when a metabolic processes of host are integrated into the microbe
opportunistic pathogens
members of normal microbiota that produce disease under certain circumstance
characteristics of skin for microbiota
mechanical strong barrier
inhospitable environment (slightly acidic pH, high [NaCl], low in moisture)
inhibitory substances
what type of microbes live on the skin?
gram positive, halophiles
staphylococci (s. epidermidis)
micrococci (m. luteus)
diphtheroids
sebum
fluid secreted by oil glands that accumulates and provides hospitable environment for p.acnes
where on the eye are bacteria found?
small numbers on conjunctiva of eye
mostly s. epidermidis
bacteria on the external ear are similar to flora found where?
the skin as well as fungi
what causes dental caries
oral bacteria
esp. s. mutans and lactobacillus
how to mouth bacteria survive removal?
adherence to gums and teeth
cause formation of dental plaque, caries, gingivitis, and periodontal disease
pharynx and trachea contain what type of bacteria?
gram positive
esp. staph (S. epi), micrococci (m. lutes), diphtheroids, strep. (alpha- and beta- hemolytic)
nasopharynx contain (high/low) pathogenic bacteria
low
Which part of the respiratory tract is sterile?
lower respiratory
due to ciliary escalator, alveolar macrophages, and lysozyme in mucus
what causes movement of microbes in lower respiratory tract?
ciliary escalator
continuous stream of mucous generated by ciliated epithelial cells
stomach host defense mechanism
acidic conditions
only survive if passed thru quickly or if ingested in food particles
duodenum has (many/few) organisms
few
pH becomes more alkaline in this part of the small intestine.
ileum
flora present is similar ot colon
where is the largest microbial population in the body?
large intestine
how are microbes eliminated from the colon?
peristalsis
desquamation
movement of mucus
high reproductive rate so readily replaced
microbes of the colon are (aerobic/anaerobic)
anaerobic
bacteria found in large intestine (11)
e. coli bacteroides fusobacterium lactobacillus enterococcus bifidobacterium enterobacter citrobacter proteus klebisella candida
where is there a state of flux in microbial [populations?
female genital tract
caused by menstrual cycle
kidneys, ureter, and bladder microbes
free of microbes
distal urethra = few microbes
lactobacilli bacteria
predominate in vagina
grow on glycogen secretions
produce H2O2
principle microbiota of skin (8)
Propionibacterium Staphylococcus Corynebacterium Micrococcus Acinetobacter Brevibacteria Candida Malassezia
Conjuctivia principle microbiota (7)
staph epidermidis s. aureus diphtheroids propionibacterium corynebacterium streptococci micrococcus
nose microbiota
s. aureus
s. epidermidis
diptheroid
throat microbiota
s. epidermidis
s. aureus
diphtheroids
streptococcus pnumoniae
haemophilus
neisseria
what keeps bacteria out of skin?
lots of contact but hard colony to survive
sweat secretion and oil glands –> antimicrobial
low moisture
very salty
keratin is good, strong barrier
eye environment
similar to skin but also have mucous membrane secretions and tears (lysozyme) and blinking to eliminate microbes
mouth environment
warm, moist, presence of food (lots of bacteria here)
biting, chewing, moving tongue, salvia dislodge
large intestine environment
largest microbiota – available nutrients and moisture
mucus and shedding + epithelial enzymes keep bacteria from colonizing
Reproductive microbial environment
acid tolerant (vagina)
mucus and shedding of lining microbes from colonizing in uterus
pH of urine and urea are antimicrobial
cilia and mucus expel microbes from the cervix
