Bailey: Gram - pathogens

Question 1

what are the two classes of gram - pathos at mucosal surfaces?

Answer 1

1. enterobacteriaceae

2. vibrionoaceae

Question 2

what species are in enterobacteriaceae?

Answer 2

1. escherichia coli
2. salmonella spp
3. shigella spp
4. klebsiella spp
5. proteus spp

Question 3

defenses of mucosal surfaces

Answer 3

1. innate immunity
2. adaptive immunity (generated in lymph nodes)
3. nonspecific barrier defenses

Question 4

oral health practitioners care about GI disease because…

Answer 4

feces, food, fluids, fingers, flies, fomites fornication

Question 5

which natural barrier defenses help protect against gram - patho infection?

Answer 5

1. secretory substances
2. anatomical and physiological barriers
3. indigenous microbiota

Question 6

secretory antimicrobial compounds

Answer 6

1. lysozyme (meramidase) cleaves btwn NAG and NAN
2. lactoferrin: bacterioststic bc sequesters iron
3. cathelicidin: disrupts bact mem
4. defensins: creates pores in microbes

Question 7

how do patho bacteria overcome innate defense barriers?

Answer 7

1. acid resistance
2. fimbriae/pili (adhere to tissue to avoid being shed)
3. bacterial structures

Question 8

why are macrophages an imp component of mucosal immunity?

Answer 8

they recognize microbes via pattern recognition, they become activated (also initiates imflamm response), and can kill microbes

Question 9

gram - invasive bacterial pathos and symptoms

Answer 9

salmonella spp
shigella spp

LI, small vol of stool, bloody stool, leukocytes in stool, tissue ulcerations

Question 10

gram - toxin producing bacterial pathogen

Answer 10

V. cholerae

Entertoxigenic coli

Question 11

shigella entry, spread, multiplication

Answer 11

• very small inoculum size
• basal layer not resistant to infection
• survives stomach bc acid resistance
• multiply/colonize in colon
• released into lamina propria, ingested by macrophages, inflamm response causes illness

Question 12

shigella dysenteriae type I

Answer 12

• different
• gastroenteritis presents as invasive diarrhea
• produces shiga toxin (disrupts NA absorption)

Question 13

what 2 main diseases does salmonella cause?

Answer 13

1. gastroenteritis (typhimurium and enteritidis serotypes)

2. typhoid fever (typhi and paratyphi serotypes)

Question 14

2 species of salmonella

Answer 14

S. bongori

S. enterica (all medically important species)

Question 15

salmonella infection

Answer 15

• fecal-oral transmission

- relatively large innoculum

Question 16

salmonella invasion

Answer 16

• induce cell signalling path, increase incellular Ca
• induce surface ruffles and uptake of organism that remains in cell vesicles for many hours
• released to LP, induces Na Cl loss from host cells
• macs engulf most, typhoid serovars grow in them

Question 17

salmonella typhi

Answer 17

• strictly human patho

- asymptomatic carriers

Question 18

gram - toxin producing pathos

Answer 18

1. vibrio spp
2. entertoxigenic e coli

-SI, copious amts of watery stool, no blood in stool, no leukocytes in stool, no tissue damage

Question 19

virulence factors of V cholerae infection

Answer 19

• flagella
• pili to adhere to mucosal tissue
• cholera toxin (phage encoded)

Question 20

enterotoxigenic e coli (ETEC)

Answer 20

• travelers diarrhea
• large infectious dose
• CFA on fimbrae to adhere to mucosal tissue
• produces toxins LT and ST responsible for disease

Question 21

Tx for secretory diarrhea

Answer 21

oral rehydration (sugar and salt)
antibiotics help shorted duration/reduce severity

Question 22

hybrid misfit gram - bacteria pathos

Answer 22

enteropathogenic e coli (EPEC)
enterohemorrhagic e coli (EHEC)

lower SI, upper LI, colonization causes attaching and effacing lesions, blood in stool with EHEC

Question 23

EPEC

Answer 23

• prevalent in newborns
• noninflamm secretory diarrhea
• distal SI
• large infectious dose
• no traditional exotoxins
• intimate adherence pattern (attach and efface lesion)

Question 24

what causes diarrhea with EPEC?

Answer 24

malabsorption due to microvilli disruptions, and tight jnctn dusruption

Question 25

EHEC

Answer 25

- has set of EPEC genes - produces toxin for hemolytic uremic syndrome - cattle are primary reservoir - attaching effacing lesion - produces shiga like toxin

Question 26

most common form of bacterial infection of an organ system

Answer 26

UTIs

Question 27

proteus mirabilis virulence factors

Answer 27

- flagella - specific fimbriae adhesin - hemolysins - IgA protease - urease (raised pH of urine)

Question 28

klebsiella virulence factors

Answer 28

- pili - enterotoxin similar to ST and LT - aerobactin - antiphagocytic capsule

Question 29

helicobacter pylori

Answer 29

- most prevalent gram - GI bug - oral-oral, oral-fecal transmission - slow bacterium - no animal reservoir

Question 30

small gram - pathos

Answer 30

chlamydiae rickettsiae ehrlichia

Question 31

chlamydiae

Answer 31

-small -gram - no peptidoglycan in cell walls obligate intracellular pathos -depend on host for ATP -complex development cycle

Question 32

chlamydial infections

Answer 32

- leading cause of preventable blindness in world - most common agents of STIs - droplet/direct contact infection - infect mucosal epi cells - localized (eyes lungs genitals) - spread by fingers, glies, fomites, fornication

Question 33

C. trachomatis infections

Answer 33

- genital tract - usually asymptomatic in females - infections can be acute or chronic - infants can contract it during birth leading to conjunctivitis and pneumonia

Question 34

chlamydophila pneumoniae

Answer 34

- most prevalent chlam. path in population - asymptomatic or acute resp response - often observed in pts with atherosclerotic heart lesions

Question 35

rickettsiae

Answer 35

- small gram - rods - obligate intracellular bacteria - zoonoses - non energy parasites - no flagella or endospores