med micro gram positive bacteria Flashcards
1
Q
types of gram positive bacteria (8)
A
genus staphylycoccus, genus streptococcus,enterococcus, bacilus, listeria, nocardia, myobacterium tuberculosis, myobacterium avium complex
2
Q
types of genus staphylococcus
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aureus, epidermidis, haemolyticus, methicillin resistant S. aureus
3
Q
Staphylococcus aureus phyisiology and structure (2 important things)
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inhibits chemotaxis and phagocytosis, inhibits proliferation of mononuclear cells(also spherical cocci shape, non motile , non spore forming)
4
Q
the slime layer in Staphylococcus aureus binds to:
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tissues and foreign bodies (catheters, grafts, prostehtic valves, joints and shunts)
5
Q
peptidoglycan layer of Staphylococcus aureus
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half of cell wall by weight, penicillin binding proteins (catalyze the construction of the peptidoglycan layer, targets of penicillins and other beta lctam antibiotics); bacterial resistance ot meticillin and related penicillins
6
Q
how does bacterial resistance to meticillin and related penicillins occur?
A
mediated by acquisiton of a gene (mecA); codes for a novel penicillin-binding protein, PBP2; penicillins cannot bind, retains is enzymatic activity.
7
Q
teichoic acids in Staphylococcus aureus
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major component of cell, a specific AN is stimulated when tehy arebound to peptidoglycan
8
Q
Protein A in Staphylococcus aureus
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not found on coagulate negative staphylococci, bound to peptidoglycan layer, affinity for the Fc receptor IgG (1, 2 and 4)
9
Q
coagulase (virulent factors) in Staphylococcus aureus
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clumping factor, binds to fibrinogen adn converts it to insoluble fibrin, causes Staphylococcus to aggregate
10
Q
exfoliative toxins in Staphylococcus aureus
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serine proteases split the intracellular bridges in teh stratum granulosum and epidermis
11
Q
enterotoxins in Staphylococcus aureus
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stimulate release of inflammatory mediator in mast cells, increases intestinal peristalsis and fluid noss, n/v
12
Q
Toxic shock syndrome toxin 1- associated with Staphylococcus aureus
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stimulates proliferation of T cells and release of cytokines, produces leakeage of cellular destrictio nof endothelial cells
13
Q
enzymes associated with Staphylococcus aureus
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NFLH!; hyaluronidase, fibrinolysin, lipases, nucleases
14
Q
hyaluronidase
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hydrolyzes hyaluronic acids in connective tissue; pormotes spread in tissue
15
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fibrinolysin
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dissolves fibrin
16
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lipases
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hydrolyzes lipids
17
Q
nucleases
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hydrolyzes DNA
18
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epidemiology of Staphylococcus aureus
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direct contact with fomites, survive on dry surfaces for long periods of time, shedding of bacteria common, persistent nasopharyngeal carriers, oropharnyx in adults, nasopharynx in children , GI, URO,
19
Q
clinical manifestations of bullous impetigo in Staphylococcus aureus
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localized blisters culture +, erythema nearblister, nikolsy sign NOT presen, infancts and young children*,
20
Q
staphylococcal food poisoning Staphylococcus aureus clinical manifestations
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prsent in food: processed meats, ham and slated pork, custard filled pastries, potato salad, ice cream; asympotomatic nasopharyngeal colonization ; heating food will NOT inactivate the heat stable toxin
21
Q
4 types of pyogenic staphlococcal infects
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(iFFC) impetigo, folliculitis, furuncles(boils), carbuncles
22
Q
impetigo
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pyogenic infection (relating to pus), prmarily on face and limbs, begins as small macule, crusting after pustule ruptures, 2º spread to adjacent skin sites
23
Q
folliculitis
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pyogenic infection in hari follicles, base of follicle is raised and redened, collection of pus beneath epidermal surface (A STYE)
24
Q
Furuncles
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underlying collection of dead adn necrotic tisuse, can rain spontaneoulsy or after surgical incision, large raised nodules
25
carbunles
furuncles coalesce and extend to deeper suncutaneous tissue, can form multiple sinus tracts, associated with chills and fevers,, INDICATE SYSTEMATIC SPREAD
26
5 clinical syndromes assocaited wtih Staphylococcus aureus
endocarditis, pneymonia/empyema, osteomyelitis, septic arthritis, staph epidermis or other coagulace negative staphylococci.
27
what's special about the endocarditis in S. epidermis and S. lugdunensis
infect native and prostehtic heart valves
28
Staphylococcus saprophyticus
predilection for causing urinary tract infections in young, sexually active women.
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important lab nots about Staphylococcus aureus
Gram +, and forms CLUSTERS on agar media
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resistance to Staphylococcus aureus
penicillinase , semisynthetic penicilins(resistant to Beta lactamase hydrolysis. MRSA strands resistant to all beta lactam AB
31
treatmetn in hospitals vs. outpateint for Staphylococcus aureus
inhospotal: vancomycin IV, out patient: clindamycin, TMP/SMX, Doxycycline
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pneumonia and empynea
consoldation and abscess formation in the lungs
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septic arthristis
erythmatous joint with collection of purulent material in the joint
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SSSS- Staphylococcal scaled skin syndrome caued by? initial infection?
exfoliative toxin, initial infection: oral, nasal cavities, throat, umbilicus
35
Genus streptococcus facts
gram-postive, arrange in pairs or chains, most are faculative anaerobes, carbohydrate fermentation into lactic acid
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streptococcus structure
spherical cocci, growth is optimal on enriched blood agar media, short chains, large zones of beta hemolysis
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virulence of anti-phagocytic streptococcus
hyaluronic acid, interferes with phagocytosis
38
virulence of M and M like proteins in streptococcus
binds Beta globulin fctor H, H protein degrades C3b , inactivates C5a
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adheres and invasion into host cells is mediated by
FML: F protein, M protein, lipoteichoic acid
40
toxins produced by streptococcus (7!)
streptococcal pyrogenic exotoxins, stretolysin S, stretolysin O, stretokinas A&B, Dnases, antireptolysin O AB (ASO)
41
streptococcal pyrogenic exotoxins
heat-liable toxins; produced by lysogenic strains, enhance release of inflammatory cytokines, *responsible for sever streptococcal disease,
42
streptolysin S is responsible for ?
beta hemolysis in streptococcus
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characteristics of stretolysin S in streptococcus
oxygen stable, cell-bound hemolysin (nonimmunogenic); lyses: erythrocytes, leukocytes, platelets; stimulates release of lysosomal contents after engulment
44
characteristics of streptolysin O in streptococcus
oxygen labile hemolysin, lyses erythorocytes, leuekocytes, platelets,
45
characteristics of antireptolysin O (ASO) Antibodies
useful for documenting recent group A streptococcal infection, anti-ASO test.
46
Streptokinase A and B characteristics (5) with streptococcus
medites cleavage of plasminogen, plasmin cleaves fibrin adn fibrinogen, lysis of clots and fibrin deposits, facilitates the rapid spread of S. pyogenes, antistreptokinase AB are useful markers for infection
47
DNAses characteristics
depolymerize free DNA present in pus, reduces the viscosity of the abcess material and faciliates spread, AB, useful in cutaneous infectiosn
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epidemiology of streptococcus
transietn colonization, URT, pharyngitis and soft tissues, strains with different M proteins, repiratory droplet, breaks in skin
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streptococcus pyogenes A associate it with
bacterium and fascitis
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streptococcus pyogenes A pharyngitis
reddened pharynx with exudates, cervical lymphadenopathy
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streptococcus pyogenes A scarlet fever
diffuse erythematous rash, from chest to lower extremeties, complication of streptococcal pharyngitis !
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streptococcus pyogenes A pyoderma
localized skin infection with vesicles progressing to pustules
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localize skin infectiosn with pain, inflmmation, LN enlargement and systemic sympotoms
streptococcus pyogenes A eripelas
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streptococcus pyogenes A cellulitis
infection that involves subQ tissues
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streptococcus pyogenes A nectoritizing fascitis
deep infection involves destrictio of muscle and fat layers
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streptococcus pyogenes A TSS
multiorgan sustemic infection, resembing staph TSS, bacteremia and fascitis!!
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do patients with scarlet fever develop renal disorders?
yes, glomerulonephritis
58
what causes erysipelas and waht are teh characteristics of this infection
streptococcus pyogenes group A!; and localized skin infection with main, inflmmation, LN enlargement, adn systemic symptoms
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non supportive infections of streptococcus pyogenes A (6)
rheumativ fever, inflammatory changes, heart (pancarditis), hoints (arthralgias to arthritis), blood vessels, subcutaneous tissues
60
treatment to streptococcus pyogenes A
penicillin! or oral cephalosporin or vancomyocin for patients allergic to penicillin; to prevent rheumatic fever start AB therapy withn 10 days in patients with pharyngitis
61
structural importance of streptococcus agalctiae (group B)
gram +, narrow zone of beta hemolysis, group specific carbohydrate, polysaccharide capsule interferes with phagocytosis, respobsuble for neonatal disease!!!! !
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epidemiology of streptococcus agalctiae (group B)
asymptomatic colonization, URT, genitourinary tract,
63
what are the five conditions placing neonate at higher risk for infection
PROM (premature rupture of membranes), prolonged labor, preterm birth, disseminated maternal group B streptococcal disease, mother w/o type specific AB adn low complement level
64
early on-set disease of neonatal streptococcus agalctiae (group B)
acquiredin utero/at birth characteristics include: bacteremia, pneumonia, meningitis, spesis work up, neurological common in children with meningits.
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late on-set neonate disease streptococcus agalctiae (group B)
acquired from exogenous source (mother or another infant), develops b/w 1 week and 3 months
66
treatment of streptococcus agalctiae (group B)
penicillin G, vancomyocin for patients allergic to penicillin, given at least 4 hours before delivery
67
streptococcus pneumoniae important characteristics
community aquired pneumonia + otitis media; oval or lancet shaped, diplococci or short chains, teichoci cid rich in phosphocholine , autolytic amidase in cell wall!
68
waht population is at greatest risk for s. agalactiae infectino and what are the characteristics of infection
neonatal ; prom, prolonged labor, preterm birth, disseminated group B strep, mother w/o specific AB
69
what are the SIX pathogenic mechanisms of streptococcus pneumoniae
surface protein adhesions, secretory IgA Protease, Pneumolysin, Teichoic acid and Peptidoglycan Fragments, Hydrogen peroxide, Phosphocholine
70
surface protein adhesins pathogenic mechanism of streptococcus pneumoniae
ability to colonize oropharynx
71
secretory IgA protease pathogenic mechanism of streptococcus pneumoniae
prevents bacterial envelopment in mucus
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pneumolysin pathogenic mechanism in streptococcus pneumoniae
destroys ciliated epitehlial cells and phagocutic ellsby creating pores in membranes; tissue destruction
73
teichoic acid and peptidoglycan fragment pathogenic mechanism in streptococcus pneumoniae
prodced by amidase, acitivate the alternative complement pathoway, producing C5A, C3A, IL-1 and TNF-alpha, mediates the inflammatory process
74
hydrogen peroxide pathogenic mechanism in streptococcus pneumoniae
tissue damage
75
phosphocholine pathogenic mechanism in streptococcus pneumoniae
cell entry survival and sprad of isease
76
what bacterium is responsible for UTI, why?
S. saprophyticus
77
who are at greater risk for fulminant sepsis in streptococcus pneumoniae?
people with hematologic disorder (malignancy, sickle cell disease, or functional asplenia)
78
pneumococcal pneumoniae triad
fever, chillls and pulmonary infiltrate ; comunity acquired associated with viral strand 3
79
clinical manifestation sin pneumococcal pneumoniae
severe shaking chill, sustanined fever, symptoms of viral respiratory tract infection 1-3 days before onset, producive cough ; BLOOD tinged sputum ; chest pain (pleurisy
80
treatment of pneumococcal pneumoniae
penicillin, or patients allergic to penicillin fluoroquinoline or vancomyocin with eftriaxone
81
lab diagnosis identification for s. agalactiae
negative catalize test, positive CAMP, diffusible substance released from group B,
82
features of enterococcus
growth in increase concentrations of NaCl and bile salts, arranged in pairs adn short chians, grow aerobicallay and anaerobically
83
enterococcus pathogenesis and immunity (4)
furface adhesin proteins (allows bidng to human cells; intestines and vagina); cytolysins and preteases , resistant AB treatment, resistance
84
epidemiology of enterococcus
colonizes GI of humans and animals, normal flora limits spread to other mucosal surfaces , broad spectrum of AB, cephalosporins naturally resistant
85
clincail disease of enterococcus
Urinary Tract Infection: (3): dysuria/pyruia: hospitalized patients with indwelling uringary catheter, receiving broad spectrum cephalosporin AB; Peritonitis: usually after abdominal trauma or surgery; Endocarditis: infection of endothelium or valves or heart, assosciated with persistent bacteremia
86
dysuria/pyruia
hospitalized patients with indwelling uringary catheter, receiving broad spectrum cephalosporin AB
87
Peritonitis
usually after abdominal trauma or surgery
88
Endocarditis
infection of endothelium or valves or heart, assosciated with persistent bacteremia
89
Bacillus chacracteristics
aerobic and faculative anaerobic spore formers, clostridium, strictly anaerobic spore formers, 2 day old rice!
90
characteristics of bacillus cereus
heat stable, heat liable enterotoxin, issue destruction mediatedby cytotoxic enzymes, inlcuding cereolysin and phospholipase, capable of causing an anthrax like disease in the immunocompromised!
91
pathogenesis of bacillus cereus 2 types of enterotoxins
heat stable - emetic form of disease; heat-liable form of disease: diarrheal form of disase
92
bacillus cereus dirrheal form of disease
stimulates the adenylate cyclase-cyclic adenosine monophosphate system in intestinal epithelial cells, leading to profuse watery diarrhea
93
clinical in heat stable enterotoxin in bacillus cereus
not destroyed when rice is reheated, emetic form of disease, contaminated rice!
94
heat ressitant spores in bacillus cereus
spires germinate if not refrigerated, bacteria multiply rapidly, intoxication
95
treatment of bacillus cereus
vancomyocin, clindamycin, ciprofloxacin, gentamicin, eye infections ust be treated proper refrigeration.
96
listeria characteristics
only recognized in humans, faculative anaerobic rod, grow from 1-45ºC, grow in high salt concentration , exhibit tumbling in broth, weak beta hemolysis on SBA. motile at RT
97
listeria restrictions
neonates, eldery, pregant women, patents with defective cellular immunity.
98
pathogenesis of listeria
contaminated food ingestion the stress reponse genes resist proteolytic destruction; internanlin A, adheres to host cell membrane via cadherin
99
initial site of infection of listeria
enterocyte and M cell of peyer pathces,
100
entry into ____ leads to diseeminated disase
macrophages!; positive regulatory factor gene; membrane lysis and intracellular replication
101
primary source of listeria
soil and decaying vegetable matter, fecal carriage 1-5% of healthy ppl
102
human listeriosis foods primarily contaminated
milk, soft cheese, undercooked meat and pultry
103
listeria in neonatal early onset
granulomatosis infantisepticia, acquired transplacentally in utero, disseminated abscesses, granulomas in multiple organs
104
listeria in neonatal late-onset disase
acquired at or shortly after birth, presents as mengiocephalitits with septicemia
105
listeria in healthy adults
influenza like illness w/ o w/o gastroenteritiz.
106
disease in pregnant women listeria clinical
present as primary bacteremia, disseminated disease with hypotenstion and meningitis
107
high risk people for listeria
avoid eating raw or partially cooked food, animal origin, soft cheeses, unqashe raw vegetables
108
lab diagnosis for listeria
CSF typically shows no organisms, serotype 4b responsible for most infections in neonates and adults; culture : beta hemolysis on sheep blood agar, hemolysis is weak, hemolysis is enhances when grow next to beta hemolutic s. aureus; positive CAMP test
109
treatment of listeria
combo of gentamicin with penicillin ; resistnace to cephalosporins, macro slides and tetracyclines
110
when and what foods are often contaminated with L. monocytogenes?
milk, soft cheees,e undercooked meat and poultry ; WARM MONTHS.
111
Nocardia characteristics
strict aerobic rod, thought to be a fungus, branched form in tissues and culture, strucuture similar to myobacterium;
112
Nocardia pathogeneiss $4
bronchopulmonary diease, chronic localized pulmonary disease, cutaneous ocardiosis, pulmonary and cutaneous disease characteristics
113
bronchopulmonary disease Nocardia
high predilection for hematogenous spread to CNS or skin
114
high risk patients for Nocardia
patient with T cell deficiencies produced by diseae, patients on immunosuppressive therapy,: usually occurs in IC patients with bronchitis, emphysema, asthma, bronchiectasis
115
chronic localized pulmonary disease Nocardia
IC patients, bronchitis/empyshema/asthma/bronchiectasis
116
cutaneous nocardiosis Nocardia 4 presentations
mycetoma, lumphocutaneous disease, superfiical skin infection with abscess formation, cellulitis
117
pulmonary and cutanous disease characteristics
necrosis, abcess formation: bronchopulmonary conlonization of URT, inhalation/aspiration into the lower airways ; Primary cutaneous nacardiosis: traumatic intro
118
what are the characteristics of a mycetoma and what pathogen is involved
nocardia!; mycetoma, lymphocutaneous disease, superifical skin infection with abscess formation, cellulitis;
119
what pathogen increases the rsik of premature rupture of membrances PROM during pregnant
Steptococcus Agalactiae
120
what gene is responsible for the development of MRSA
staphlyococcus aureus
121
protection from phago cytic killing in Nocardia
cataliase, superoxide dismutase
122
characteristics of mycetoma in Nocardia
painless, chronic infection primarily on the feet, localized subcutaneous swelling, suppuration, formaitn of multiple sinus tracts, drraiing sinus tracts usually open on skin surface
123
characteristics of myobacterium tuberculosis
nonmotile aerobic rod, lipid rich wal, resistent to many disinfectants, acid fast bacteria!
124
classifications of myobacterium tuberculosis
acid fastness, mycolic acids, high CG content in DNA
125
pathophysiology of myobacterium tuberculosis
acid fastness, slow groth , resistant to detergents, and antibacterial AB, complex gram positive structure
126
Liparabinomannan (LAM)
functionally related to O-antigenic lipopolysaccharides present in other bacteria
127
Arabinogalactans
consist of d-arabinose, and d-galactose
128
pathogenesis of myobacterium tuberculosis
respiratory airways; minute infectious particles penetrate to alveoli, phagocytized by alveolar macrophages, evasion of macrophage killing; inactivates oxidants formation
129
macrophages secrete in myobacterium tuberculosis
interleukin 12 and tumor necrosis; recruitment of t cells and NK cells to areas of infected macrophages AND interferon gamma- increasesd intracellular killin and macrophage activation
130
what are granulomas what are the components of a granuloma?
prevents further spead of bacteria, it's constituents include: alveolar macrophages, epithelioid cells, langhans giant cells (fused epithelial cells), necrotic mass surrounding by a ense wall of CD4, CD8, NK T cells
131
caseous granulomas
encapsulated with dribin; bacteria protected from macrophage killin, can remain dormant; reactivation can occur uears uearer,d ecrease in immune responsiveness
132
epidemiology of myobacterium tuberculosis
infecitous aerosols, person to personal contant, humans only natural reservoir
133
populations at increased risk for myobacterium tuberculosis
homelesss, drug and alcohol abusers, prisoners, HIV infection
134
describe MTB infection in immunocompentent patients
restricted to lungs, initial pulmonary focus is in the middle or lower lung fields, replication ceases 3-6 weaks after exposure;
135
what's miliart TB?
disseminated tuberculosis
136
pulmonary disease in immunocompromised patietns myobacterium avium complex
middle aged or older men with history of smoking, elderly female non somers
137
disease in HIV infected patients myobacterium avium complex
dissemiated, *terminal stages; initiatd in localized LN
138
skin test rectivity
defined by diameter of area of induration, examined and measured 48 hours later * HIV patietns maynot show response to tuberculin skin test; control antigens should be used
