Micro

Question 1

what 4 infections occur almost exclusively in diabetics

Answer 1

Rhinocerebral mucormycosis
necrotizing otitis externa
emphysematous UTIs
emphysematous cholecystitis

Question 2

in which diabetics is rhinocerebral mucormycosis seen? what organism causes it?

Answer 2

T1DM

Rhizopus oryzae

Question 3

in which diabetics is necrotizing otitis externa seen? what organism causes it?

Answer 3

T2DM

pseudomonas aeruginosa

Question 4

What organism is implicated in emphysematous UTIs?

Answer 4

candida albicans

Question 5

General characteristics of Rhizopus oryzae?

Answer 5

infects diabetics w/ ketoacidosis
ubiquitous, found in soil
affinity for iron rich, acidic environments
tropism for blood vessels
not dimorphic

Question 6

What are the characteristics of the Rhizopus hyphae?

Answer 6

broad
irregularly branched
aseptate
'ribbonlike'
'moose antlers'
fragile
have globuse sporangia

Question 7

What are the rhizopus virulence factors?

Answer 7

avirulent
siderophore rhizoferrin
ketone reductase

Question 8

transmission and pathogenesis of rhinocerebral mucromycosis

Answer 8

inhalation of spores -> germination in nasal passages -> invasion of blood vessels -> invasion of sinuses, eyes, cranial bones, brain -> infarction, necrosis, thrombosis RAPID!

Question 9

possible symptoms of rhinocerebral mucromycosis

Answer 9

blood vessel and nerve damage
facial numbness
periorbital edema, proptosis, blindness
black eschars on palate or nose

Question 10

How do you diagnose rhinocerebral mucromycosis

Answer 10

CT or MRI
gauge sinus involvement
plate and stain on KOH
plate tissue on SDA

Question 11

treatment of rhinocerebral mucromycosis

Answer 11

debridement + ampho B + control of diabetes

Question 12

General characteristics of pseudomonas aeruginosa

Answer 12

gr - rod
ubiquitous
encapsulated
oxidase +
aerobe
salt tolerant
growth in water sources
iron acquisition

Question 13

virulence factors of pseudomonas aeruginosa

Answer 13

capsule (alginate)
spreading factors
exotoxin A
biofilm
intrinsic and acquired antibiotic resistance
pili

Question 14

What plate do you use to grow Pseudomonas aeruginosa and what does it look like?

Answer 14

MacConkey
mucoid colonies
odor of grapes
blue or green growth

Question 15

what is the pathogenesis of necrotizing otitis externa

Answer 15

being in EAC -> may invade soft tissue

Question 16

what are the symptoms of necrotizing otitis externa

Answer 16

severe otalgia, otorrhea
swelling, erythema
temporary hearing loss

Question 17

diagnosis of necrotizing otitis externa

Answer 17

CT or MRI to determine extent

otherwise on PE

Question 18

treatment of necrotizing otitis externa

Answer 18

debridement + systemic and topical antibiotics + control of diabetes

Question 19

what predisposing factors lead to diabetic foot infections

Answer 19

neuropathy
peripheral vascular dz
hyperglycemia
impaired immunity

Question 20

what is the primary pathogen in a foot infection? and what is the typical number of pathogens present?

Answer 20

s. aureus

5-7 (polymicrobial)

Question 21

Type I necrotizing fasciitis characteristics

Answer 21

polymicrobial (avg 4.6 isolates)

most often involves feet with rapid extension into legs

Question 22

Type II necrotizing fasciitis characteristics?

Answer 22

usually strep pyogenes
community acquired
predisposing factors: trauma, infection, drug use, burns, chx pox

Question 23

What is fournier gangrene?

Answer 23

type I

GI enteric organisms that spread into ant abdominal wall and into scrotum

Question 24

symptoms of necrotizing fasciitis

Answer 24

pain out of proportion to apparent severity
bullae common
erythema, local warmth, edema, skin induration

Question 25

treatment of necotizing fasciitis?

Answer 25

debridement + antibiotics + diabetes control + supportive therapy