Clostridia Chlamydia, Rickettsia, Ehrlichia, Mycoplasma

Question 1

clostridium traits

Answer 1

anaerobic
gram + rods
pro endospores
found in env. 
prod proteinaceous toxins resp for disease sympt.

Question 2

clostridium species and their assoc diseases

Answer 2

c. difficile - pseudomembranous colitis
c. perfringens - cellulitis, gas gangrene, food poisoning
c. botulinum - botulism
c. tetani - tetanus

Question 3

traits of pseudomembranous colitis

Answer 3

spread thru c. dificile endospore
leading cause of nosocomial diarrhea
disease state assoc w/ antimicrobial drugs b/c it induces spore state
spore releases toxin
toxin causes diarrhea 
doesn't invade bowel wall

Question 4

C. difficile toxin A vs. B

Answer 4

A - enterotoxin - damages mucosa, used to diagnose
B - cytotoxin
both act in cytoplasm of host

Question 5

C perfringens traits

Answer 5

in soil and intestinal tracts of animals
path of wound infection esp war wounds
local and systemic effects

Question 6

conditions of wounds that cause c. perfringens spores to germinate

Answer 6

anaerobic
compromised blood supply
calcium ions
available peptides and AA’s

Question 7

toxins of c. perfringens

Answer 7

prod. 12 toxins
alpha toxin damages cell membranes and causes gas gangrene
toxins cause necrosis of muscle tissue
if untreated leads to shock renal failure and death

Question 8

treatment/ prevention of c perfringens

Answer 8

amputation
high oxygen concentrations
prompt care and restoration of arterial blood supply

Question 9

how does c. perfringens cause food poisoning? and what results from it?

Answer 9

sporulating c. perfringens prod. enterotoxin in intestines

results in self-limiting diarrhea

Question 10

clostridium botulinum traits

Answer 10

found in soil and marine sediments

spores are heat resistant (not toxin) and germinate in canned food

Question 11

botulinum toxin traits

Answer 11

produces 8 neurotoxins
among most deadly poisons
spore doesn't need to be present to get 
toxin formed from 1 prot w/ a heavy non toxic chain and light toxic chain
botulism, just the toxin
used in bioterrorism

Question 12

3 types of botulism

Answer 12

food-bourne
wound botulism
infant botulism (has a slow onset, and causes babies to be floppy - favorable outcome)

Question 13

mechanism of c. botulinum toxin

Answer 13

prevents release of Achol. neurotransmitter by using zinc metalloprotease to cleave the receptor proteins
people get flaccid paralysis w/in 12-36 hrs.

Question 14

c. botulinum treatment

Answer 14

trivalent antitoxin isolated from horses

Question 15

c. tetani traits

Answer 15

ubiquitous in GI tracts of humans and animals and soil

infect wounds

Question 16

toxin of c. tetani

Answer 16

tetanospsmin = toxin

has heavy and light chain connected by disulfide bridge, individual chains are non-toxic

Question 17

mechanism of tetanus

Answer 17

toxin attaches to n near wound and moves up to its body where it inhibits neurotrans release and inhibitory input
typically starts as lockjaw, then moves down to trunk area
results in reflex spasms and spastic paralysis

Question 18

treatment/ prevention

Answer 18

DPT vaccine
antitoxin s/b administered w/ penicillin G
wound region should be surgically cleared to elliminate spores

Question 19

small gram negtive pathogens

Answer 19

chlamydiae rickettsiae and ehrlichia

Question 20

chlamydiae traits

Answer 20

gram - 
no peptidoglycan in cell wall
obligate intracellular path
energy parasites (dep on host for ATP)
comp dev. cycle

Question 21

4 species of chlamydia

Answer 21

human paths:
c. trachomatis
c. pneumoniae
animal paths:
c. psittaci
c. pecorum

Question 22

traits of chlamydial infections in general

Answer 22

causes preventable blindness
thought every human has had it
droplet or direct contact infection of mucosal ep. cells
localized
spread by fingers, flies, fomites and fornication

Question 23

c. trachomatis infection traits

Answer 23

usually asymptomatic in females
infants can get it during birth causing conjunctivitis and pneumonia
infections can be acute or chronic

Question 24

mechanism of c. trachomatis infection

Answer 24

elementary bodies as as nutrients/ hormones to bind to specific receptors and get into cells via receptor mediated endocytosis
EB’s modify endocytic vesicle by keeping it at 6.2 pH and preventing it from fusing w/ lysosome, it also uses host glycolipids as camouflage
EB changes into active RB which uses host resources and divides by binary fission

Question 25

how do RB’s take up nutrients?

Answer 25

use tube like structures to feed off cytoplasm so they don’t have to leave the vacuole

Question 26

traits of trachoma

Answer 26

caused by chlamydia trachomitis
effects eyes inflaming conjunctiva
causes blindness and cornea scarring

Question 27

traits of lymphogranuloma venerum

Answer 27

chlamydial STD
systemic b/c it attacks lymph and genital tract
mainly in dev. countries

Question 28

traits of chlamydophila pneumoniae

Answer 28

most common chlamydial infection
asymptomatic or acute respiratory response
esp seen in people w/ atherosclerotic heart lesions

Question 29

treatment of chlamydia pneumoniae

Answer 29

target RB forms of antimicrobials
has to penetrate 4 membranes: host plasma membrane, inclusion membrane, chlamydial outer membrane, chlamydial cytoplasmic membrane

Question 30

traits of rickettsiae

Answer 30

sm. gram - rods
obligate intracellular bact
zoonoses

Question 31

capable of ind. metabolism

Answer 31

no flagella or endospores

Question 32

rickettsiae transmission

Answer 32

only hard mountain tick is naturally infected
spread thru tick bites via bloodstream
cause endothelial cells to endocytose then lyse phagosome w/ phospholipase
exit cell thru cell lysis, projections or budding

Question 33

injury /treatment to host from rickettsiae

Answer 33

lysis of cells results in hemorrhagic blood rash

treated by immune syst. or antibiotics

Question 34

typhus group fevers of rickettsiae

Answer 34

r. prowazekii - typhus fever, transmitted by lice
r. typhi - murine typhus, trans by rats and fleas
orientia tsutsugamushi - scrub typhus , NO RASH

Question 35

traits of ehrlichia

Answer 35

obligate intracellular bact
transmitted by lone star tick
infects monocytes and macrophages
dev. w/in host cell vacuoles first as reticulate cells (RC) then as dense core cells (DC)

Question 36

echrlichiosis diagnosis

Answer 36

patients dont have symptoms at first or know of tick bite
handling is harzardous
req. cell culture or animal inoculation and diagnostic tests (titer, assay, complement fixation, or agglutination)

Question 37

traits of mycoplasma

Answer 37

v. small
req sterol (for cell membranes)
colony looks like a fried egg
no cell wall
found in other mammals and birds

Question 38

4 species of mycoplasma

Answer 38

m. pneumoniae
m. genitalium
m. hominis
ureaplasma urealyticum

Question 39

m. pneumoniae encounter/entry

Answer 39

humans = only reservoir
walking pneumonia - not cured by penicillin
mild and contagious infections
adhere to resp. ep

Question 40

spread of m. pneumoniae

Answer 40

cause bronchopneumonia
cell resp thru lymphocytes
impair ciliary fcn by releasing tissue toxic substances
causes hemolytic anemia (cold clumping of IgM), encephalitis and erythema multiforme (rash)

Question 41

types genital mycoplasmas

Answer 41

m genitalium - sim. to pneumoniae
affect newborns:
m. hominis
u. urealyticum