CHAPTER 13: INTRO Flashcards
microbe human interactions: how do humans and microorganisms interact?
with development of biofilms
what is normal flora?
normal mutual or commensal relationship with the body
what is an infection?
when pathogenic microbes penetrate the host and enter tissue to MULTIPLY
what is a pathogen?
an infectious agent
what is an infectious disease?
an infection that causes damage or disruption to tissue and organs
what areas of the body can come in contact with external microbes?
- skin
- mucuous membranes
- upper resp tract
- GI tract
- urethra opening
- external genitalia
- vagina
- ear canal
- external eye (lash, follicle, lids)
internal organs contact w microbes
they are microbe free
transients
microbes in the body for SHORT amount of time
residents
microbes that become established
microbial antagonism?
bacterial flora prevents overgrowth of harmful microbes in the body
endogenous infections
normal flora is introduced to a site that was previously sterile
- infection caused by a pathogen that was present in their body prior to infection
uterus and infants:
- sterility
- flora
- sterile until just before birth
- breaking fetal membrane exposes infant, feeding/handling infant will introduce what will develop into their normal flora
how do you change transients? residents?
transients: hygiene
residents: stable and predictable, they are less influenced by hygiene
variations in flora of gi tract reasons?
exposure to environment and variations in the flora distribution is due to changes in conditions: temp, pH, oxygen, anatomy etc….
where is most of the flora? where is it most diverse?
large intestine, rectum, and mouth
most diverse in the mouth
what kind of environment does the intestine favor?
what is usually here in small numbers?
anaerobic bacteria
- coliforms present
what metabolic waste does bacteria make
vit B12, pyridoxine, riboflavin, thiamine, acetic acid, butyric acid, propionic acid
host can use these
what contributes to odor?
released by intestinal bacteria: gasses, amine, skatole
first organism to colonize the resp tract
streptococci
how does S.aureus enter the body
nasal, vestibule (ear), and anterior nasopharynx
how does Neisseria enter the body
mucous membrane of nasopharynx
how does Haemophilus enter the body
tonsils and lower pharynx
unfavorable enviros for permanent residents
- bronchi
- lungs
- lower resp tract
where do males harbor bacteria in urethra
anterior urethra
vaginal changes that influence normal flora
- pH, estrogen, glycogen
how does flora fight against infection
- other influences?
creates enviros to protect against infection by enhancing host defenses
other influences on flora: antibiotics, dietary changes, disease
why do probiotics not work sometimes
microbiome is complex between diff ppl, contains well adapted bacteria
probiotics only have few species of bacteria, these strains are well adapted for industrial growth rather than gut growth
