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Derm ex1
Micro skin mucosa
34
Medical
Professional
11/18/2011

Additional Medical Flashcards

 


 

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Term
use for blood agar
Definition
for growing out most non-fastidious bacteria
Term
use for chocolate agar
Definition
fastidious bacteria, gonococcus
Term
use for macconkey agar
Definition
gram neg. enteric rods, also lactose fermenters
Term
use for lowenstein/jensen agar
Definition
promotes the growth of Mycobacteria, esp. the TB bacillus
Term
use for sabouraud dextrose agar
Definition
promotes growth of fungi
Term
define Microaerophilic
Definition
refers to low oxygen tension (<5%) + some CO2.
Term
Staph bacteria
Definition
-gram pos.
-catalase pos.
-non-motile
-facultative anaerobe

S. AUREUS is beta hemolytic, most staph won't grow on mcconkey
Term
catalase test
Definition
catalase liberates hydrogen and oxygen from hydrogen peroxide

most bacteria except for streptococci are pos.
Term
coagulase test
Definition
the clumping of plasma
Term
hemolysis on plates
Definition
beta is the the clearing of blood on a blood agar plate

alpha is partial clearing, brown/green zones
Term
how to determine is an organism is Strep pneumo?
Definition
add a disc, optochin (P disk). S. pneumo is the only alpha-hemalytic streptococci that is sensitive to it
Term
how to test for streptococcal pharyngitis, i.e. with S. pyogenes?
Definition
add an A-disc, bacitracin. S. pyogenes is the only beta-hemalytic strep that is sensitive to it
Term
what does a lactose test show?
Definition
that something is a lactose-fermenter by changing colors (red because pH goes down). often this is e. coli or kleibsella.

most gram neg rods are not
Term
oxidase activity
Definition
Pseudomonas, Campylobacter, Helicobacter, the Vibrios, and Pasteurella are positive

they will turn blue in a reagent tube within 30 sec.
Term
india ink
Definition
useful in detecting cryptococcus
Term
some pts. on s. aureus
Definition
enzymes present: coagulase, penicillase, catalase

components of cells wall:
-capsule inhibiting opsonization and phagocytosis
-peptidoglycan for osmotic stability
-protein A which binds IgG and causes it to act as a leukocyte chemoattractant
-teichonic acid which is a receptor for bacteriophages

infections usually cause increase in temperature, rash, HYPOtension, and abnormal liver function tests
Term
Scalded Skin Syndrome
Definition
Starts as local redness and inflammation;
It then spreads;
Blisters then form on the skin;
Squamous layer of the epithelium begins to peel off;
The epithelium does recover, and 2nd infections usually do not occur.
Term
Toxic Shock Syndrome
Definition
an example of “superantigen” disease –
superantingens overly stimulate proliferation of T
cells and release of cytokines which lead to
leakage or destruction of endothelial cells; then,
other severe systemic problems arise.
▪ first discovered in 1980: associated with tampon
use
Term
some pts. on s. epidermidis
Definition
catalase positive, coagulase neg., novobiocin SENSITIVE, slime layer, forms non-hemolytic colonies on blood agar
Term
some pts. on s. saprophticus
Definition
catalase positive, coagulase neg., novobiocin RESISTENT, common in urinary tract

capsule consists of hyaluronic acid

linked to:

PHARYNGITIS (or sore throat) [mostly Group A strept.]
SCARLET FEVER
TOXIC SHOCK SYNDROME (STSS)
Various skin lesions:
o ERYSIPELAS
o CELLULITIS
o PYODERMA
o IMPETIGO
NECROTIZING FASCIITIS: a serious & potentially
life-threatening disseminated skin disorder
RHEUMATIC FEVER: a cardiovascular disorder
ACUTE GLOMERULONEPHRITIS: a potentially
serious renal disorder
MENINGITIS
Term
most serious cause of pharyngitis?
Definition
strep pyogenes

can develop into:
rheumatic fever
glomerulonephritis


TRUE OF ALL GROUP A STREP:
contains M protein which prevents phagocytosis
A-disk sensitive (bacitracin)
can serve as a super-antigen
Term
bacteria implicated in neonatal disease, post-pardem sepsis, and meningitis
Definition
Strept. agalactiae; resistent to bacitracin
Term
some pts. on pseudomonas aeruginosa
Definition
-motile
-gram-negative bacillus;
-does not ferment any sugars [forms colorless colonies on MacConkey agar]
-oxidase-POSITIVE
-LPS/endotoxin in its cell wall
-antibiotic resistance is associated with stricture of the porin proteins
-Associated with cystic fibrosis
Term
major cause of acne
Definition
Propionibacterium acnes

-gram pos. rod. technically an anaerobe, but can be aerotolerant
-combines with sebum and promotes inflammatory response
Term
what do actinomyces resemble?
Definition

hyphae fungi because they are gram pos. rods which grow in filamentous forms

 

they colonize the upper airways and have been associated with granulomatous lesions which contain pus and can abscess

Term
gonorrhea
Definition

the gram neg diplococcal "gonococcus"; the diplococci may be inside or outside PMNs

 

can be assymptomatic in women, cause purulent discharge in

 

extragenital manifestations:

-conjunctivitis

-pharyngitis

-proctitis

-pelvic inflammation (mostly women)

 

must plate on chocolate agar under micro-aerophilic conditions and also check for oxidase

Term

virulence factors in Neisseria gonorrhoeae

Definition

-capsule

-endotoxin

-IgA protease

-antigenic variation (causes problems for immunity and vaccines)

-pilli (for attachment to host cells)

Term
syphilis
Definition

caused by treponema pallidum

 

causes "chancre" lesion which is raised, hard, and necrotic, but painless

-differed from CHANCROID which is soft and painFUL

 

secondary maculpapular rashes are seen on extremities if primary disease has not been treated

 

dx is confirmed by serology

Term
what can cause a chancroid?
Definition
Haemophilusducreyi – a short gram-negative rod; culturable on chocolate agar;

a chancroid is soft and painful
Term
HPV
Definition
a dsDNA virus causing anogential warts and intraepithelial cervical neoplasia (types 16 and 18 major culprits)
Term
candidiasis
Definition

not really considered an STD because it is part of normal flora, but can cause irritating vaginitis; caused by Candida albicans

 

often brought on by treatment with another AB, thus allowing the native infection to expand

Term
Trichomoniasis
Definition
Caused by a motile, pear-shaped protozoan parasite, Trichomonasvaginalis

an itchy, bad smelling, green yellow vaginal discharge
 
perform a WHIFF test
-mix swab with 10% KOH, smells fishy is positive
Term
bacterial vaginosis
Definition

bad smelling discharge of "clue cells" caused by gardnerella vaginalis (gram variable rod)

 

arise because normal inhabiting lactobacilli are not kept in check to supress gardnerella vaginalis

 

15-25% of women are affected, possible causes include:

Having multiple sex partners
Cigarette Smoking
Poor nutrition
Douching
Using an IUD

-Bad personal hygiene

Term
genital herpes
Definition

caused by HSV-2 a dsDNA virus (type 1 is the type which causes cold sores)

 

characterized by painful vesicular and ulcerative lesions of the penis, cervix, vulva, & vagina + localized lymphadenopathy

 

Dx: Tzanck smear, culture, serology, molecular tech.

 

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