Flashcards
Micro - Gram positive organisms
Cards in this deck (143)
- 1Transmission of Streptococcus pyogenes (+ when is it facilitated)droplets (saliva or nasal secretions)
facilitated by overcrowding - 2Virulence factors of Strep. pyogenes (6)M protein
Lipoteichoic acid
Streptokinase
Hyaluronidase
DNAse
Anti-C5a peptidase - 3How does M protein affect virulence (3)adherence factor
anti-phagocytic
antigenic (induces Ab for death) - 4How does lipoteichoic acid affect virulenceadherence factor
- 5How does streptokinase affect virulenceactivates proteolytic enzyme plasmin which breaks up fibrin blood clots
- 6How does hyaluronidase affect virulencecause tissue destruction, allowing the spread of infection
- 7Diseases caused by local invasion/exotoxin release by Streptococcus pyogenes (4)Streptococcal pharyngitis
Skin infections
Scarlet fever
Streptococcal toxic shock syndrome - 8Symptoms of streptococcal pharyngitisRed swollen tonsils and pharynx
Purulent exudate on tonsils
Fever
Swollen + tender lymph nodes - 9Suppurative complications of streptococcal pharyngitis (2)Otitis media
Acute mastoiditis - 10Non-suppurative complications of streptococcal pharyngitis (2)Acute glomerulonephritis
Acute rheumatic fever - 11Skin infections due to streptococcal pharyngitis (3)Impetigo
Erysipelas + cellulitis
Necrotising fasciitis - 12What is impetigo (+ signs)confined infection of the superficial layers of skin
(multiple sceptic spots on face, arms + legs) - 13What are erysipelas and cellulitisskin infections that develop as a result of bacterial entry via breaches in the skin barrier
- 14What is the difference between erysipelas and cellulitsErysipelas involves the upper dermis and superficial lymphatics
Cellulitis involves the deeper dermis and subcutaneous fat - 15What is necrotising fasciitisinfection spreads to deep subcutaneous tissue with the destruction of muscle and fat
- 16Which virulence factor of streptococcus pyogenes permits necrotising fasciitis to occur and howM proteins block phagocytosis and allow the bacteria to rapidly move through tissue and bullae form -> gangrene and systemic signs
- 17How does streptococcus pyogenes infection cause scarlet fever (+ signs)Delayed-type skin reactivity to the
pyrogenic toxin (exotoxin)
(fever and a scarlet-red rash beginning on the trunk and neck and then spreads to the extremities) - 18Signs of streptococcal toxic shock syndrome (4)pain
fever
chills
multi-organ failure - 19Antibody-mediated diseases caused by streptococcus pyogenesRheumatic fever
Acute post-streptococcal
glomerulonephritis - 20Pathogenesis of rheumatic fever secondary to streptococcus pyogenes infectionAb cross-reacts with cardiac tissue -> immune complex deposition on heart -> valvular heart disease
- 21Symptoms of rheumatic fever secondary to streptococcus pyogenes infection (7)fever
myocarditis
arthritis
chorea
subcutaneous nodules
erythema marginatum
neurological involvement (Sydenham's chorea) - 22Pathogenesis of acute post-streptococcal glomerulonephritisAb-Ag complexes are deposited in the glomerular basement membrane = activate the complement cascade
- 23Symptoms of acute post-streptococcal glomerulonephritis (3)oedema (face and extremities)
hypertension
albumin and blood in the urine - 24How can acute post-streptococcal glomerulonephritis developmost patients recover normally but some develop permanent renal damage and warrant lifelong dialysis or renal transplant, or it may be fatal
- 25What Lancefield group is streptococcus pyogenesLancefield group A
- 26Metabolism of streptococcus pyogenesmicroaerophilic
catalase negative
β Haemolytic - 27Why is streptococcus pyogenes β haemolytichas enzymes that destroy RBCs and WBCs
- 28Which enzymes does streptococcus pyogenes have that make it β haemolytic (2)Streptolysin O - oxygen labile and antigenic
Streptolysin S - oxygen stable and non-antigenic - 29Gram stain of streptococcus pyogenesGram positive cocci in chains
- 30What does streptococcus pyogenes grow on and what inhibits its growthstandard laboratory media
inhibited by bacitracin - 31What laboratory test is done to detect pharyngitis due to streptococcus pyogenes (+ findings)throat swab for rapid antigen detection test (RADT)
detects Group A antigen - 32Treatment of Streptococcus pyogenes (3)Penicillin G
Penicillin V
Erythromycin - 33Treatment for rheumatic feverContinuous prophylactic antibiotics to prevent repeat strep throat infections
- 34Treatment for invasive streptococcus pyogenes infectionsadd clindamycin to treatment
- 35Where does streptococcus agalactiae colonise (3)gastrointestinal tract
genitourinary tract
vagina (25% of pregnant women) - 36Diseases caused by streptococcus agalactiae infection (5)neonatal meningitis
neonatal pneumonia
neonatal sepsis
sepsis in pregnant women
sepsis and pneumonia in elderly patients with diabetes or neurological disease - 37Symptoms of neonatal meningitis due to streptococcus agalactiae infection (4)fever
vomiting
poor feeding
irritability - 38Risk factors for neonatal meningitis due to streptococcus agalactiae infection (4)maternal colonisation
premature delivery
prolonged rupture of membranes
intrapartum fever - 39What Lancefield group is streptococcus agalactiaeLancefield group B
- 40Metabolism of streptococcus agalactiaefacultative anaerobe
catalase negative
β haemolytic - 41Gram stain for streptotoccus agalactiaegram-positive cocci in pairs or short chains
- 42Where do you obtain culture from for streptococcus agalactiae (3)CSF
Urine
Blood - 43Treatment for streptococcus agalactiae infectionPenicillin G
- 44Diseases caused by group C streptococci (3)puerperal fever
tonsilitis
wound sepsis - 45Diseases caused by group G streptococci (2)URTIs
endocarditis - 46Which organisms are in the viridans group streptococci (5)streptococcus sanguis
streptococcus mitis
streptococcus mutans
streptococcus anginosus (milleri)
streptococcus bovis - 47What disease does streptococcus mitis causeinfective endocarditis in previously damaged valves
- 48What disease does streptococcus mutans cause (+ how)dental infection
(bind to teeth and ferment sugar which produces acid and dental cavities) - 49What does streptococcus anginosus causepurulent infections - abscesses in liver and brain
- 50Metabolism of viridans group streptococciα haemolytic
- 51Gram stain of viridans group streptococciGram positive
- 52Culture of viridans group streptococcigreen colouration on blood agar plates
can grow in presence of optochin - 53Streptococcus pneumonia transmissiondroplet (respiratory)
- 54Virulence factors of streptococcus pneumoniae (3)capsule
adhesins
pneumolysin - 55How does the capsule in streptococcus pneumoniae affect its virulenceActivates complement and cytokine release → damage to host cells.
- 56How do adhesins in streptococcus pneumoniae affect its virulencehelp it colonise the oropharynx
- 57How does pneumolysin in streptococcus pneumoniae affect its virulencehelps it invade cells by activating complement and cytokine release -> damage to host cells
- 58Diseases caused by streptococcus pneumoniae (4)pneumococcal pneumonia
sinusitis + otitis media
pneumococcal meningitis
bloodsream infection (bacteraemia) - 59Symptoms of pneumococcal pneumonia (3)pleuritic chest pain
SOB
purulent sputum - 60Complications of pneumococcal pneumonia (4)parapneumonic effusion
empyema
lung abscess
bacteraemia - 61Predisposing factor for pneumococcal pneumoniainfluenza
- 62What is sinusitis and otitis media due to streptococcus pneumoniae preceded byURTI
- 63Who is affected by otitis media in streptococcus pneumoniae infectionyoung children
- 64Who is affected by sinusitis in streptococcus pneumoniae infectionall age groups
- 65Metabolism of streptococcus pneumoniaefacultative anaerobe
catalase negative
α haemolytic - 66Gram stain of streptococcus pneumoniaeGram-positive diplococci or short chains
- 67Quellung test for streptococcus pneumoniaeSwelling when test tested against anti-serum containing anti-capsular antibodies
- 68Eneterococcus faecalis + faecium transmissionfrom hands, environment, contaminated food, or water
- 69Virulence factors for enterococcus faecalis + faeciumProtein and carbohydrate factors enable binding to cells (eg. dextran -> heart valves)
Intrinsic/acquired antibiotic resistance facilitates survival and multiplication - 70Toxin released by enterococcus faecalis + faeciumHaemolysins - cause damage to the host cells
- 71People affected by enterococcus faecalis + faecium infections (5)Recent surgery
Underlying disease
Recent antibiotics
Prolonged hospital stay (especially in ICU)
Immunosuppressed/Immunocompromised
It is nosocomial/opportunisitc - 72Diseases caused by enterococcus faecalis + faecium infections (4)UTI
Subacute Bacterial Endocarditis
Blood stream infections
Wound Infections - 73Lancefield group of enterococcus faecalis + faeciumLancefield group D
- 74Metabolism of enterococcus faecalis + faeciumFacultative anaerobe
Catalase negative
Usually gamma haemolytic (i.e. does not lyse blood cells) but some are alpha haemolytic - 75Gram stain for enterococcus faecalis + faeciumgram-positive
- 76MacConkey agar of enterococcus faecalis + faeciumGrow in the presence of bile salts (40% bile or 6.5% NaCl)
- 77Treatment for enterococcus faecalis + faecium infectionampicillin + aminoglycoside
(if resistant give vancomycin)
(if VRE - give linezolid, daptomycin, and nitrofurantoin) - 78Which is more common: enterococcus faecalis or faeciumEnterococcus faecalis
- 79Streptococcus bovis - where is it foundFaeces of cattle and other domestic animals (cats, dogs, horses, pigs)
- 80Main portal of entry for streptococcus bovisGIT; some cases urinary tract and oropharynx
- 81Diseases caused by streptococcus bovisEndocarditis associated with colon cancer
UTI
Septicaemia (rare)
Neonatal meningitis (rare) - 82Where is streptococcus equinus foundAlimentary canal of horses and in horse faeces
Seldom found in humans - 83What Lancefield group is streptococcus bovis + equinusLancefield group D
- 84Metabolism of streptococcus bovis + equinusFacultative anaerobe
Catalase negative
Oxidase negative
Gamma haemolytic (no haemolysis) - 85Gram stain for streptococcus bovis + equinusgram positive
- 86MacConkey agar of streptococcus bovis + equinusGrow in the presence of bile salts (40% bile only)
- 87Where do peptostreptococcus colonise (4)oral cavity
gastrointestinal tract
genitourinary tract
skin - 88Diseases caused by peptostreptococcus infections (5)aspiration pneumonia
sinusitis
brain abscess
intra-abdominal abscesses
pelvic infections - 89Where is Staphylococcus aureus found on the body (3)moist skin folds
mucosal surfaces
nasopharynx - 90When does staphylococcus aureus infection occurbreak in the mucosal lining
- 91How is staphylococcus aureus transmittedPerson-to-person spread by direct contact
- 92What are the classes of virulence factors of Staphylococcus aureus (3)Protective Proteins
Tissue-Destroying Proteins
Binding-Proteins - 93What protective proteins does Staphylococcus aureus have (6)capsule
protein A
coagulase
haemolysins
leukocidins
penicillinase - 94What does the capsule in staphylococcus aureus do (2)inhibits chemotaxis of immune cells
inhibits phagocytosis - 95What does protein A in staphylococcus aureus do (3)binds IgG
preventing opsonization
prevents phagocytosis - 96What does coagulase in staphylococcus aureus doallows fibrin formation around organism
- 97What do haemolysins in staphylococcus aureus dobind to platelets and monocytes and open up small pores -> osmotic lysis
- 98What do leukocidins in staphylococcus aureus doact on polymorphonuclear leukocytes
- 99What tissue destroying proteins does Staphylococcus aureus have (3)Hyaluronidase
Staphylokinase
Lipase - 100What does hyalurodinase in staphylococcus aureus dobreaks down connective tissue -> spread
- 101What does staphylokinase in staphylococcus aureus doplasminogen activator that lyses fibrin
- 102What binding proteins does staphylococcus aureus have (3)surface proteins
fibrin/fibrinogen binding protein
matrix binding proteins = fibronectin + adhesins - 103What do surface proteins of staphylococcus aureus doattachment to epithelial and endothelial proteins
- 104What do matrix binding proteins of staphylococcus aureus dopromotes collagen attachment
- 105What toxins do staphylococcus aureus release (3)enterotoxin
toxic shock syndrome toxin (TSST-1)
exofoliatin - 106When do you find enterotoxinfood poisoning
- 107What does exofoliatin of staphylococcus aureus docause scalded skin syndrome
- 108What are the diseases caused by exotoxin release by staphylococcus aureus (3)gastroenteritis
toxic shock syndrome
scalded skin syndrome - 109Pathophysiology of gastroenteritis caused by staphylococcus aureus (+ symptoms - 5) (+ duration of symptoms)Grow on food and produce exotoxin → ingestion → nausea, vomiting, diarrhoea, abdominal pain, and occasionally fever
12-24hrs - 110Pathophysiology of toxic shock syndrome by staphylococcus aureus (+ symptoms - 3)Tampon use: TSST-1 (superantigen) penetrate vaginal mucosa → releases TNF and IL-1 + enhances susceptibility to endotoxin → pyrexia, hypotension, rash with desquamation (palms and soles)
- 111How does toxic shock syndrome progressrenal failure
disorientation without focal neurological signs
severe myalgia (↑CPK) - 112Pathogenesis of scalded skin syndrome due to staphylococcus aureusExfoliative toxin A and B establishes localised infection + cleaves middle dermis = large patches of necrotic epidermis peels off easily (Nikolsky’s sign) → reveal moist red skin beneath
- 113Complications of scalded skin syndrome due to staphylococcus aureussepsis
superinfection
dehydration - 114Diseases resulting from direct organ invasion by staphylococcus aureus (4)pneumonia
meningitis
osteomyelitis
acute bacterial endocarditis - 115Symptoms/signs of pneumonia due to staphylococcus aureusAbrupt onset of fever, chills
lobar consolidation of the lung
rapid destruction of lung parenchyma - 116Progression of pneumonia due to staphylococcus aureus (2)effusions
empyema - 117Risk factors of pneumonia due to staphylococcus aureusCF
viral URTI
ventilation
aspiration - 118Symptoms of meningitis due to staphylococcus aureus (6)High fever
stiff neck
headache
decrease alertness
coma
focal neurological signs - 119Who is affected by osteomyelitis due to staphylococcus aureusboys <12yrs old
- 120Which bones are most affected in osteomyelitis due to staphylococcus aureus infectionvertebrae
- 121Presentation of osteomyelitis due to staphylococcus aureus infection (4)warm
swollen tissue
systemic fever
shakes - 122How is osteomyelitis due to staphylococcus aureus diagnoseddirect needle aspiration
bone scan - 123Progression of osteomyelitis due to staphylococcus aureus (+ cause)Septic arthritis - hot, swollen joint
(from BSI) - 124What is acute bacterial endocarditis due to staphylococcus aureus infection secondary toblood stream infection
- 125Gram satin of staphylococcus aureusGram positive cocci in clusters (grapes)
- 126Metabolism of staphylococcus aureuscatalase positive
coagulase positive
beta-haemolytic - 127Culture of staphylococcus aureusgolden yellow pigment
- 128PCR of staphylococcus aureusdetection of rRNA
- 129Treatment of gastroenteritis due to staphylococcus aureussymptomatic treatment only
- 130Treatment of toxic shock syndrome due to staphylococcus aureus (2)rapid IV antibiotics (flucloxacillin/1st gen cephalosporins)
source control - 131Treatment for scalded skin syndrome due to staphylococcus aureuswound care
rehydrate
antibiotics (flucloxacillin/1st gen cephalosporins) for 7-10 days - 132Treatment for pneumonia due to staphylococcus aureusdepends on where they got the infection (CAP/HAP)
(+ vancomycin/teicoplanin if MRSA risk) - 133Treatment for endocarditis due to staphylococcus aureusIV antibiotics +/- valve replacement/repair - (gentamicin + vancomycin/amoxicillin
for 4-6 weeks) - 134Treatment for blood stream infection due to staphylococcus aureusantibiotics for more than 2 weeks (flucloxacillin/1st gen cephalosporins)
- 135Treatment for bone/joint infection due to staphylococcus aureusantibiotics for 6 weeks
(flucloxacillin/1st gen cephalosporins) - 136MRSA - how does it come aboutproduction of an altered penicillin binding protein 2a (PBP2a) which is encoded by the mecA gene carried on a mobile genetic element known as staphylococcal cassette chromosome (SCCmec)
- 137How is MRSA methicillin resistantpenicillin binding protein 2a (PBP2a) takes over peptidoglycan cell wall assembly when normal PBP (transpeptidase) is inhibited
- 138What does community-acquired MRSA cause (2)skin infections
necrotising pneumonia - 139Which virulence factor does community-acquired MRSA usePanton Valentine Leukocidin (PVL) toxin
- 140Who does community-acquired MRSA affectyounger, healthier patients
- 141Treatment for MRSA (3)Vancomycin (IV)
Daptomycin (IV)
Clindamycin (IV + PO) - 142Virulence factors for Staphylococcus epidermidis (2)capsule
biofilm - 143—
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- IC1 Flashcards on Micro - Gram positive organisms, created by Erica Lai on 26/04/2019.
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