1- Gram Positive Cocci

7/25/2019 1- Gram Positive Cocci

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Bacteria – Gram Positive Cocci

Staph aureus

“The Golden Staf o Moses” – feat. Staph aureus

• Robes of Moses are violet (Gram +)

Gram + cocci

o Catalase+

Catalase test (converts hydrogen peroxide to water) – use cat to denote catalase

and separate from Strepo Coagulase+ (brinogen → brin) – Parting o the red sea coag!lation

o

hemolytic (moses is carrying a red light ul that has in it – b"c it loo#s li#e a glowing

halo on agar$)o Mannitol salt agar – will turn agar yello! (b"c it can ferment mannitol – tall man% man

is tall" !earing yello! roes)

• Protein # is main vir!lence factor (staf #)

o Component of staph a!re!s cell wall& inds $c portion o antiody (prevents complement

from binding to the same area and initiating opsonisation"complement)

• Coloni'es the nose (ro%en of nose)

• nammatory disease

o S* a!re!s ca!ses pneumonia (coughing man and camel)

Shows !p as patchy inltrate on chest x+ray (patchy green roes) &cosahedron lamps hanging o, (icosahedron+shaped caps!le of vir!s)

-s!ally a secondary infection that occ!rs after imm!ne system is wea#ened by a

viral infectiono S* a!re!s is the most common ca!se of septic arthritis (andages on %nees o camel)

o .bscesses li#e impetigo' uruncles' caruncles (denoted by camel(s red

erythematous humps)o #cute acterial ndocarditis (!omen clutching her chest in ear and hearts all on

the camel) Camel getting spoo%ed (rapid onset)



/hin# of s* a!re!s endocarditis i &* drug user (mortar and pestle !ith

medication vials) and will most commonly a,ect tricuspid valve ( pyramids behind her)

o ,steomyelitis (infection of the bone – - .sh ones) – there are 0 b"c s* a!re!s is the most

common ca!se of osteomyelitiso Scalded s%in syndrome (man getting a really ad sunurn on his head)

Mediated by toxin e/oliative to/in (protease)

o To/ic Shoc% Syndrome

/SS/ (/oxic shoc# syndrome toxin) – s!perantigen that ca!ses non+specic binding of

M1C class to /+cell receptors → overactivation and cyto#ine storm (shoc% isdenoted y the super cape !ith lightning olt on it)

o $ood poisoning

Ca!se sx in 2+3 hrs b"c preformed toxins (rapid onset denoted y running camel)

0omen is clutching her mouth li%e she is aout to thro! up (staph food

poisoning more associated with vomiting than diarrhea) Meats and mayonnaise left o!t too long (on her camel)

• M1S# 2Methicillin resistant staph3 #ureus) – denoted by Pharaoh sho!ing mercy

o 4ecome resistant by changing its penicillin binding proteins (545)& which b!ild the cell wall*

(pharaoh is !sing altered pyramid uilding people)o /reat with vancomycin (vancomycin caravan – note that it will be an act!al van in f!t!re

s#etchy6s% b!t a van wo!ldn6t t this era$)

• f methicillin sensitive& !se 4acillin (a penicillin& showing by the pharaoh holding a pencil) – 4a

or staf

Staph pidermidis and Saprophyticus

“5eauty and the Plumer” – feat. Staphylococcus epidermidis and Staphylococcus saprophyticus

• 7iolet color (8ram 9 organism)



• S3 epidermidis (centered aro!nd the plumer) – given the name b"c it is all over o!r s#in

o nfection sites:

nfects articial ;oints and hardware (notice all the hard!are aro!nd there<)

nfects indwelling catheters (notice the catheters all under the sin% )

nfection of implant – most common ca!se of endocarditis in articial heart valves

(literal heart valves)o 5io.lms (polysaccharides) are the main reason why it can infect these places – gun% on

the pipes and tues and valves – also acts as coating to protects it from expos!re toantibiotics and imm!ne cells

/reat s!spected S* epidermidis infected endocarditis with *ancomycin (vancomycinvan outside)& however& yo! have to event!ally replace the valve

o S* epidermidis is part of the normal s#in ora (dirt on pl!mber6s hands)* /h!s& it can easily

contaminate blood c!lt!res (petri dish drip pan) when blood is drawn*o Staph epi is 4ovoiocin6sensitive (novo so!nds li#e navel% plumer(s elly utton

hanging o!t) =ovobiocin is how yo! disting!ish S* epidermidis from S* saprophytic!s (which is

=ovobiocin resistant)

S3 saprophyticus (yo!ng lady on the co!nter)

o 4ovoiocin resistant (her elly utton isn(t sho!ing$)

o Common ca!se of -/s& especially in sex!ally active females (7irty emale holding a

yello! drin% that loo%s li%e ladder !ith ureters coming out)

• Common properties of both S* epidermidis and S* saprophytic!s

o Catalase positive (catalase+ cat hanging o!t)% this is how yo! can tell Staph from Strep

o 8rease positive 2#mmonia spray ottle)

-rease converts !rea into ammonia*

o Coagulase negative (4egative 9ello% it6s not coag!lated at all& ;!st a smooth shiny

s!rface) Coag!lase separates these from Staph* .!re!s

Strep pyogenes 2Group # Strep)



“The Pie Genies( 5a%ery” – feat. Strep. Pyogenes (Group A Strep)

Strep pyogenes 2Group # Strep)

o ncapsulated acteria (encaps!lated pie)

:ot #pple 5ie – caps!le is made of hyal!ronic acid% we ma#e this& so strep

pyogene6s caps!le is not imm!noreactive*o hemolytic lightul

o nammatory infections (pyogenic):

&mpetigo – pyogenic s#in infection that loo#s >honey+cr!sted? (honey crusted

lemon pie)

• Recall that Staph a!re!s can also ca!se impetigo

Pharyngitis (strep throat) – red hand%erchie on the chef

Cellulitis and rysipelas (erysipelas is basically a very s!percial cell!litis infection

with well+demarcated borders) – ig red gloves (erythema of the s#in)o nfections ca!sed by Strep pyogenes to/in (/oxin is streptococcal pyrogenic exotoxin

(S5@)) Scarlet ever – 3 main symptoms

• Reddening and swelling of the tong!e (stra!erry tongue) – coo# lic%ing

stra!erry

• Pharyngitis – red hand%erchie

• 0idespread rash that spares the ace – red frosting smeared everywhere

on gingerread man e/cept or ace To/ic Shoc%6li%e Syndrome (/SAS) – s!perantigen (s!per cape with lightning bolt)

4ecroti;ing $asciitis (esh eating bacteria) – b!rnt gingerbread with the leg falling

o, (necrotic tiss!e% sometimes have to amp!tate) More on the SPE toxin

• S5@ . – s!perantigen (/SAS and scarlet fever)

• S5@ 4 – protease (=ec* Basc*) – 4 for b!rnt gingerbread man

• S5@ C – s!perantigen (/SAS and scarlet fever)



o 1heumatic $ever (master che – M also stands for M protein)

M protein is highly antigenic in cell wall and is responsible for Rhe!matic fever

• .ntiphagocytic (master chef swatting away g!y trying to eat c!pca#e)

• .ntigenic and elicits strong h!moral response% it creates an antibody that is

very similar to the myosin the cardiac m!scle (molec!lar mimicry) → mitralvalves damaged in RB (mitre hat worn by master chef)* /his complicationdoesn6t happen if pharyngitis is treated* 5haryngitis precipitates RB (redhand#erchief) – /ype hypersensitivity

D=@S (D=@S c!pca#es)

• oints – 5olyarthritis (ba#er b!mped the c!pca#e and frosting is on his elbow)• © (D) – heart problems: valv!lar problems leading to new m!rm!rs&

myocarditis& pericarditis

• = – =od!les (S!bc!taneo!s nod!les) – most commonly appear on extensor

s!rfaces of forearms or the elbows or #nees* Candy nod!les on c!pca#es

• @ – @rythema marginat!m – rash with thic# red borders

• S – Sydenham6s chorea – rapid invol!ntary movements (esp of hands and

face)o 5oststreptococcal 8lomer!lonephritis (5S8=)

Eamage is from circ!lating antibody+antigen complexes that deposit in glomer!l!s

(/ype hypersensitivity)

• 8lomer!lonephritis (phone cord twisted into a glomer!ler shape)

Sx: • Ear# brown or coca+cola !rine – coca cola bottle

• Bacial swelling"p!Fness (edema) – p!,y faced chef

5S8= occ!rs 0 wee#s after onset of initial Strep infection (0 wee#s later on calendar)

o Compare and contrast RB and 5S8=

=ote that:

• RB only occ!rs after pharyngitis

• 5S8= can occ!r after pharyngitis or a s!percial infection (chef with the p!,y

chee#s of 5S8= has honey cr!sted cr!mbs on his face) /x and Complication 5revention

• @arly diagnosis and treatment can prevent RB& b!t it will not prevent 5S8=

• /x with penicillin (penicillin pencil) – even tho!gh this chef has penicillin& he

still has honey cr!st cr!mbs and coca colao Dther vir!lence factors

Streptolysin D – allows lyses of R4C (D shaped don!ts that are ;elly lled and lea#ing)

• Ge generate .SD antibodies against streptolysin D

Strepto#inase – converts plasminogen to plasmin (brinolytic) (little c!pca#es with

phosphates on them) E=ases – depolymeri'e E=. (twisted bread li#e E=.)

o 1ow to di,erentiate 8ro!p . from 8ro!p 4 Strep

8ro!p . is bacitracin sensitive

• 4acitracin basset ho!nd is able to eat the twisty bread

8ro!p 4 is bacitracin resistant

o #ntistreptolysin , titer (the lady who ;!st bo!ght some streptolysin D don!ts is chec#ing

them with .b+shaped tongs) – can tell !s if we have had a recent Strep . infection

Strep agalactiae 2Group 5 Strep)



“# Galactic 5ay” – feat. Streptococcus Agalactiae (Group B Strep)

• 8ro!p 4 Strep – ca!ses serio!s infections in newborns

o 1ipp!rate positive (st!,ed hippo toy) – hydroly'es sodi!m hipp!rate

o 5olysaccharide caps!le (helmet aro!nd the hippo toy)

o

C.M5 test positive (Space camp) Eisting!ishes 8ro!p 4 Strep from all the other Streps

Ghen plated with 84S is plated with Staph a!re!s& it has an increasing area of

hemolysis (remember it6s associated with S* a!re!s b"c of moses sta, s!pportingtent)% it has nothing to do with c.M5

• /he spaceship represents a petri dish and the red arrow shows the C.M5 test

arrowhead 'one of hemolysis at the point of interaction btwn 84S and Stapha!re!s

o β+hemolytic (li#e Strep pygenes) – red β hemolysis lightb!lb

Strep pne!mo and viridans are α+hemolytic

o 4acitracin resistant (bacitracin ho!nd is in a spaces!it and can6t lic# and m!nch on the

baby)o Clinical Manifestations

Ca!ses meningitis in neonates (H2 ca!se) – meningitis space helmet Common ca!se of sepsis in neonates – red space s!it

Ca!ses pne!monia – co!ghing baby

o /ransmission

=eonates get this infection when they pass thro!gh birth canal (imagine that the

baby came o!t of the t!be part of the >mothership?)o 7agina and rectal swab for 84S at IJ wee#s to see if it is coloni'ed – all pregnant women

swabbed (IJ w# on mothership) Consider that the mother is a carrier of 84S% how do yo! prevent the infection<

• 8ive mother intrapart!m penicillin – landing legs of the mothership are

pencils stic#ing into it (penicillin pencils)

• *e* 8ive mother penicillin or ampicillin d!ring labor"delivery



Strep pneumoniae and Strep viridans

“The #lpha <night Tournament” – feat. Streptococcus pneumoniae and Streptococus viridans

• α Knight /o!rnament – α hemolysis (partial hemolysis& s!rro!nding 'one is green% green sign)

• Strep pneumoniae (Strep pne!mo #night% =!mero !no #night)o ncapsulated with a polysaccharide caps!le (armor and helmet% except chin is exposed) –

vir!lence factoro Dptochin sensitive (chin is exposed)

o Aancet shaped gram positive cocci (#night holding lance)

o 4ile sol!ble (cannot grow in bile) (m!d is bile% horse is str!ggling to wal# thro!gh m!d)

o Clinical ndings

H2 ca!se of comm!nity acL!ire pne!monia in ad!lts that generally inltrates the

lower lobes (lobar pne!monia)* Aeads to the prod!ction of r!st colored sp!t!m (letthe r!sty lobar located armor denote this)

M,PS (Sir strep pne!mo has a sL!ire with a mop% next to this g!y is a fan holding

!p a 2 sign to show that strep pne!mo is the numer one cause o these things)

• Meningitis

• Dtitis media• 5ne!monia

• Sin!sitis

o g. 5rotease (.llows for organism to invade m!cosa) – Shield that loo#s li#e the g. dimer

molec!le% shield is crac#ed and damagedo Remember that individ!als who have had a splenectomy& or have !ndergone a!tosplectomy

(li#e in sic#le cell disease) have a greater ris# of infection by encaps!lated organisms* 5atients with sic#le cell disease are partic!larly s!sceptible (sic#le on the strep

pne!mo #night6s belt)o /x with macrolides (maCRDlide crows) and ceftriaxone (tri+axe ag)

o 5revention with vaccines

.d!lt – polysaccharide vaccine



• G"o protein leads to /+cell independent response that generates gM response

(not very long lasting) Child – con;!gated to protein

• Con;!gation to a protein ca!ses it to be more energetic and generate a more

rob!st /+cell response → prod!ction of g8 Sign showing people where to sit adults on the Me!!anine" children on the Ground

• Strep viridans

o =o caps!le (;ester has no armor on)

o Dptochin resistant (;ester6s mas# with an exaggerated chin)

o 4ile resistant (don#ey has little boots on protecting him from m!d)o /he viridans gro!p& specically Strep m!tans and Strep sang!inis& are commonly associated

with dental caries (fo!l yellow teeth on don#ey) f a viridans (li#e Strep sang!inis) gets into the blood → s!bac!te endocarditis →

infection on damaged heart valves (most commonly mitral valve – M75 andrhe!matic fever)% remember this with mitre heart on the ;ester (loo#s slightlydamaged to recall that it infects previo!sly damaged valves)

Strep viridins can adhere to any brin platelet aggregate tiss!e by creating dextran

from gl!cose% dextran is li#e a gl!e (plate on ;ester6s arm and dec# of cards)

nterococcus

“Protest at the Caucus? – feat. Enterococcus

• Eon6t conf!se @nterococc!s (8ram 9 cocci) with @nterobacter (8ram negative rod)

• @* faecalis (people !nder the California ca!c!s sign) and @* faeci!m (Stop the Bees sign%)

o So many people in faecalis means that it happens more often% @* faeci!m is rarer b!t more

dangero!s (hence why the g!y is b!,er)o .ble to grow in in medi!ms of !p to *JN =aCl (Resist the * JN =* California)

o 4ile resistant (bile resistant boots and the b!, g!y resisting the policeman with the billy

cl!b)

o nfections of @nterococc!s (Eo - © /rees)

- – -/s



© + @ndocarditis

/ree – 4iliary tree infections

o @nterococc!s& especially @* faeci!m& is resistant to almost every antibiotic we have& even

7anc$ 7R@ – 7ancomycin+resistant @nterococc!s (b!, d!de resisting getting into the

7ancomycin van) -se Aine'olid (Aine on police line)

/igecycline (tiger stripes on police line

1- Gram Positive Cocci

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