strep 2 Flashcards
strep pneumonia are arranged in—-
diploccoci (pairs) and shorts cjains
capsule?
encapuslated
hemolysis?
alphla hemlytic due to pneumolysin which breaks down hemoglobin (so the H2O2 porduced by the bacteria oxidies the hemoglobin into the methhehmoglobin)
motility and spore?
none motile and none spore forming
S pneumonia virulence factors
LOOK ST SLIDE 4
1) capsule: 90 serotypes/ interferes wih phagocytosis
2)bacterial surface adhesions: pneumococal surface antigen A: choline binidng protein
3)cell wall: teichoic acid and lipotecihoic acid adherence to huamn cell receptor
choline, a component of —, allows S. pneomonia to…
enter the host cell
choline biding protein A:
-bingds to choline bining receptors which are on almost all human cells inclding epithelial cells
-Interact with immunoglobulin receptors on
the surface of epithelial and mucosal
cells—endocytoses—transport—can be
released into bloodstream and invade CNS (adherence, colonization, invasion)
The capsule interferes with phagocytosis by
Absence of receptors on phagocytic cells that recognize capsular polysaccharide
Presence of electrochemical forces that repel phagocytic cells
PspA prevent complement C3b opsonization of the bacterial cells
Inactivation of complement (PspC)
S. Pneumoniae noncapsular virulence factors
epideiolgy of strep of pneumonia: spread:
endogenous spread from colonised nasopharynx or oropharnyx to distal site (e.g., lungs, sinuses, ears, blood, meninges)
colonization is highest in——/disease is more common in–
young children/cool months
other factors:
-individuals with antedecent viral resp tract/ children and elderely are at greatert risk for meningitis/ people with hematologis disorder
main symptoms of infectious pneumonis slide 12
infections caused by S. pneumonia:
1) pneumonia: productive cough (bloody) and and fever
2) sinusititis and otitis media:
otitids media=middle ear sinusitis=paranasal sinuses
3)bactermia
4)meningitis:S. pneumoniae can spread into the central nervous system after
bacteremia, infections of the ear or sinuses, or head trauma
slide 14
ab diagnsosi of s penumonia:
specimen: sputum, nasopharynx, snus or middle ear
lage number number of PMNs, few epithelial cells/ numberous gram positive cocci in airs and chaGram stain: lancet shaped diplococci surrounded by an unstained capsule (not well observed)ins/ Fastidious organism: need an enrichment medium: Blood agar
identification of S penumonia:
look at pics slide 16
alpha hemolytic, catalase negtaive,
-bile solubility test ((Sodium deoxycholate): Isolates of S. pneumoniae are lysed rapidly
when the autolysins are activated after exposure to bile
* Optochin (ethylhydrocupreine dihydrochloride
treatment:—–for resistant strains:
penicillin, macrolide and tetracycline/vaconmycin or floroquinolone
prevention:
1) PNEUMOVAX: is 23-valent polysaccharide vaccine (PPVSV23) that is currently recommended for use in all
adults who are older than 65 years of age and for persons who are 2 years and older and at high risk for
disease (e.g., sickle cell disease, HIV infection, or other immunocompromising conditions). It is also
recommended for use in adults 19 through 64 years of age who smoke cigarettes or who have asthma
2) Prevnar: Immunization with the 7-valent conjugated pneumococcal vaccine is currently recommended for
infants younger than 5 years of age
3) On February 24, 2010, the FDA licensed a 13-valent pneumococcal conjugate vaccine (PCV13). It is
recommended for all children younger than 5 years old and for adults with certain risk factors.
enterococcus are——arranged in—
gram positive cocci/pairs and short chains
cell wall with group specifix antigen:
group D glycerol teichoic acid
resp:—–nutrition:
fac anaerobic/ fastiduious: require blood for growth
blood hemolysis:
nonhemolytic or alpha hemolytic
the bacteria can grow in prescnce of—
high C of NaCl and and bile salts
virulence:
1) adherence to host surfaces: intestinal and vaginal tissues using collagein binding adhesin and carb adhesin
2)secretion of cytolysins and proteases that casues localized tissues damage and resist antibiotic treatment
3)Enterococci either are inherently resistant to many commonly used
antibiotics
another name for bile solubility test / another name for optohcin test and LOOK ST SLIDE 18
sodium deoxycholate /ethylhydrocupreine dihydrochloride
epidemiology:—-. E. faecalis is found in the —- while E. faecium is —
Enterococci are enteric bacteria which are commonly recovered
in feces collected from humans and from a variety of animals/ is found in the large intestine in large quantinties (10 to power 7 organisms per gram)and in genitourinary tract while/ is less frquent
entercocci may be isolated—
in the resp tract or on the skin surafce of hospitalized patients who have been treated with broad spectrum antibiotics (emergence of vancomyion resistant enterococci)
most common HAI of enteroccocci:
1) UTI: dysuria (pain during urination)
and pyuria (pus) most commonly in hospitalized patients
with an indwelling urinary catheter and receiving broad
spectrum antibiotics
2)peritonitis: abdominal swelling and tenderness abdominal surgery or trauma. patients are typically actutely ill, febrile, and have positive blood cultures.
3)endocarditis: infections of heart endothelium or valves. associated with persistent bacteremia, can present acutely or chromially.
procedure of blood culture
1)obtain all supplies needed for blood culture
2) colllect 20 ml of blood needed in a synrige via venipucture with butterfly needle
3) sterilize the tops of both blood culture bottles using alcohols pads
4)dose aerobic bottle with 10 ml of blood from syringe. so same for anaerobic
1) invert both blood cultures
2)place them in automated blood culture system
3)after sensor signals positive result, remove positive blood culture
4)conduct gram stain to determine if bac are gram + or _ then subculture an aliquot of blood culture onto agar plates for susceptibility testing
slide 28
slide 29: REGLLY: go to word
REGIIIγ (Regenerating islet-derived 3 gamma), which is a protein produced by intestinal epithelial cells and Paneth cells in the gut.
laboratory diagnosis for entercoccus
1) growth in CO2 rich environment on a vaerity of media including blood and chcolate agar
2) catalase negative
3)resistant to optohcin
4)do not dissolve when exposed to bile
5) growth in bile containg 6.5% NaCl
6)Hydrolyzed esculin in the presence of bile (even if u put them in bile they are able to hydrolize esculin)
7)Produce l-pyrrolidonyl arylamidase (PYR test positive)
slide 32
treatmet of entercoccus/
resistance to….has become a major poblem,/ others used:—- but resistance is emerging.
ampicillin or vancomyocin. the use of the synergistic effect of a cell wall active antibiotic and a aminoglycoside was used ( ex: vancomyocin, ampicillian). /aminoglycosides, ampicillin, penicillin, and vancomycin/linelozoid, selected floquinolones, quinupristin/dalfopristin
case study slide 34
strep viridans/many produce —/includes those that–
heterogeneus collection of alpha hemolytic and nonhemolytic streptocci /green prigment on blood agar/lack the lancefield group gene
they colonize the—/rarely found on—becasue
GI tract. ororpharynx and the genitourinary tract./ skin surface becasue surface Fatty acids are toxic to them
like most other strep, viridans are –
nutritionally fastidious so they require complex media supplemented with blood products and frequently an incubation atmosphere augmented with 5% to 10% CO2
they are the most common cause of —
subacute bacterial endocarditis(Subacute refers to the gradual onset of the infection, as opposed to acute bacterial endocarditis, which develops quickly and is more severe.)
the S. Mutans and S. sobrinus species causes—
dental carries (cavities) and bacteremia
s. mutans are part of —/ they are equipped with rece[ptors that—
normal flora/allow it to adhere to surface of tooth creating a slimy environment
s. mutans begin to–
grown and syntheize dextran with the enzyme dextransucrase.
dextran contains a capsule that binds to the —
enamel (hard outerlayer of teeth) and forms a biofilm that consists of 300-500 bacterial cells
the—can depolymerize to—
dextran/ glucose and use the monosac as a carbon source whihc produces lactic acid n the biofilm by declacifying the enamel and leads to dental caries. so the bac use the sugar as food and produce lactic acid which is bad for t he enamel. the combination of the acid and the plaque (sticky bacteria) casues the dental carry
what results in the causative agent of decay?
the combination of acid and plaque
s Viridans cause:
baceriemina, endoacrditis,meningitids, localized infections abscess particularly s melleri
slide 40 w tloo3 for API thing
