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Flashcards in Bacterial infections Deck (24)
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1

what are 3 types of bacterial infections

staphylococcal
streptococcal
others (UTI and tooth decay)

2

Characteristics of staphylococcal infections

GRAM +VE AND FACULTATIVE
remains viable after months in dry environment
resistant to many antibiotics and disinfectants
1/4 of nosocomial infections
common inhabitants of skin and mucous membranes (anterior nares)

3

what are scope of infections

depends on degree of invasion or toxin production
range from local to systemic
characteristic local lesion (abscess)
superficial infections (folliculitis, furuncle, carbuncle, impetigo

4

what is the treatment for superficial staph infections

betafine, oral antibiotics (penicillin and cehphalosporin)

5

systemic staph infections
Ritters disease

ritters disease
- children

6

systemic staph infections
Toxic shock syndrome

- fatal condition
-drop in BP along with other usual stuff (nausea,fever,vomitting etc)
-toxins enter blood stream
-toxin shock syndrome toxin (TSST)
-associated with high use of tampons
-nasal surgery
Treated by:
- decontamination of infection site
-fluid resuscitation
-iv or oral A/B - penicillin,clindamycin, vancomycin

7

systemic staph infections
Osteomyelitis

-infection in bone
-which leads to necrosis of bone
-systemic manifestations- fever, chills, pain, muscle spasm

8

systemic staph infections
Food poisoning

-staph is the second most common reported food poison source
-salmonella is #1
incubation - 1-6 hrs,
exotoxin enters blood
most common source - skin abscesses

9

Streptococci

GRAM +VE arranged in chains, facultative
classified by
-lancefield groupings
-hemolytic patterns (alpha, beta and gamma)

10

hemolytic patterns

alpha - blood agar goes green
beta - blood agar goes white (clear)
gamma - no hemolysis

11

major species of streptococci

Beta and lancefield group A = S.pygones
Gamma - no lancefield group = S.mutans
Alpha - no lancefield group = S.pneumoniae

12

S.pneumoniae (Alpha and NA)

- strain 19A caused meningitis

13

S.pygones

Group A, Beta, only member in this group
most common strep pathogen
-resp. tract diseases
-skin infections
-bloodstream infection

14

Transmission of S.pygones

direct, droplets, food
mostly affect 5-15 years old

15

S.pygones - respiratory tract

Streptococcal pharyngitis (strep throat)
-common
-fever, coughing, swollen lymph nodes and tonsils, red throat
-purulent exudate over tonsils

16

s.pygones - scarler fever

-complication of strep throat
-infecting strain produces erythrogenic toxins
-toxin causes leaky capillaries
-bright red, diffused rash over the body including the tongue (strawberry tongue)
-skin peels off
-goes away in 5-7days

17

S.pygones - rheumatic fever

-after strep throat
-inflammation of joints and heart
-autoimmuine disorder
-acute phase- arthiritis and carditis
chronic - rheumatic heart disease

18

S.pygones - skin infections

necrotizing fasciitis
-flesh eating disease
-been around long time but its rare
-deep infection that spreads across fascial planes
-multiorgan failures
-mortality rate >50%
-prompt and extensive surgical removal

19

UTI

-2nd mst freequent reason for hospital visit
-first - resp. infection
-bacteria moves up urethra
-usually starts in bladder
-E.coli = 80%
-staph. Saptophyticus - 10%
-protein mirabilis - 5%
-females are more susceptible
-cranberry juice or Vit. C - rapid treatment

20

Oral bacteria

-75 billion bacterial cells
-dental plaque=bacteria +organic matter (food and saliva)

21

Gingivitis

-infection/inflammation of gums
-bleeding while brushing (everyone gets it)
-several streptococcal and gram -ve rods involved
-could eventually lead to tooth loss
-severe disease=acute necrotizing ulcerative gingivitis (trench mouth)

22

what kind of relationship bacteria has with viruses?

synergism

23

Tooth decay (dental carries)

-teeth do not shed cells
-primary bacteria-streptococcus mutans
-s.mutans metabolizes sugar into glucose and fructose (dissacharide)
-glucose is assembled into dextran, fructose is metabolized, producing lactic acid

24

how does fluoride help prevent dental carries?

-highly charged ion F-
-it displaces OH-in growing teeth
-it forms crystals in and on existing enamel
-decreaes 'solubility' of tooth enamel