MICROBIOLOGY PPT LECTURE NOTES | Karya Tulis Ilmiah

Morphology & Identification

 _{Gram positiveGram positive}

 _{Facultative anaerobesFacultative anaerobes}  _{Grape like-clustersGrape like-clusters}

 _{Catalase positiveCatalase positive}

 _{Major components of Major components of}

normal flora

normal flora

_skinskin _nosenose

Catalase test （过氧化氢

酶）

Pathogenesis

• Catalase

• Coagulase

• Hyaluronidase and Lipase ipase

• Hemolysin or sphingomyelinase Csphingomyelinase C

• Leukocidin

• Exfoliative Toxin

Pathogenesis of staphylococcal infections

Stye:

Stye:麦粒肿_麦粒肿

Carbuncle:

Carbuncle:痈痈

Impetigo

Suppurative

• _{Skin Skin}

 _{Furuncle; Protein A, Leukocidin, Hemolysin Furuncle; Protein A, Leukocidin, Hemolysin}  _{Stye; lipase Stye; lipase}

 _{Impetigo; contagious Impetigo; contagious}  _{Epidermal necrolysis Epidermal necrolysis}

 _{Exfoliative Dermatitis (6,7,8); Exfoliative toxin Exfoliative Dermatitis (6,7,8); Exfoliative toxin}  _{Mastitis Mastitis}

 _{Abscess (deep tissue); granulation; coagulase, hyaluronidase (burn, Abscess (deep tissue); granulation; coagulase, hyaluronidase (burn,}

wound)

wound)

• _{Systemic Systemic}

•

Food poisoning

Food poisoning

•

Toxic shock syndrome

Toxic shock syndrome

•

babies

babies

– scalded skin syndrome_{scalded skin syndrome}

* Exfoliatin_Exfoliatin

• fever_fever

• scarlatiniform_{scarlatiniform} rash rash

• desquamation_desquamation

• vomiting_vomiting

• diarrhea_diarrhea

• myalgias_myalgias • not a human infectionnot a human infection

• food contaminated from humans _{food contaminated from humans}

– growth _growth

– enterotoxinenterotoxin

• onset and recovery both occur within few hoursonset and recovery both occur within few hours

Infections associated with indwelling devices

Laboratory

• _{A. Direct examination; Gram Stain} • B. Primary media; BAP

• C. Differential Tests. 1. Mannitol Salts

2. Coagulase 3. DNase

• _{D. Phage typing}

• E. Antibiotic Sensitivity (plasmid, B lactamase) : penicillin

GRAM POSITIVE COCCI

S. aureus

 hemolytic mannitol yellow

+

-Staphylococcus (Clusters) Streptococcus (pairs & chains) Catalase

• BETA: Bacitracin S .pyogenes (group A) CAMP/Hippurate S. agalactiae (group B)

Hemolysis Coagulase

S. epidermidis

nonhem olytic (usua lly) mannitol

white

(2) ALPHA: Optochin/Bile Solubility S. pneumoniae

• GAMMA: Bile Esculin 6.5% NaCl Group D* Enterococcus

Bile Esc ulin 6.5% NaCl Group D* Non-Enterococcus

(*can also be beta or alpha hemolytic)

Note: Strep. viridans

are alpha hemolytic and negat ive for all the tests below + + + + + + +

Staphylococcus epidermidis

Staphylococcus epidermidis

• major component skin flora_{major component skin flora}

• opportunistic infections _{opportunistic infections}

– less common than less common than S.aureusS.aureus

• nosocomial infectionsnosocomial infections

– heart valves_{heart valves}

• Identification_{Identification}

– Non-hemolytic _{Non-hemolytic} ((sheep blood agarsheep blood agar))

– Does not ferment mannitol_{Does not ferment mannitol}

– Non-pigmented _{Non-pigmented}

– _{Coagulase-negativeCoagulase-negative}

Staphylococcus saprophyticus

Staphylococcus saprophyticus

•

urinary tract infections

urinary tract infections

•

coagulase-negative

coagulase-negative

Morphology & Identification

•

facultative anaerobe

facultative anaerobe

•

Gram-positive

Gram-positive

•

Chains

Chains

or pairs

or pairs

•

Catalase

Catalase

negative

negative

Cell surface structure of S pyogenes and extracellular substances

•Lancefield groups_{Lancefield groups}

*one or more species per group_{one or more species per group}

*surface antigens: M, T, R_{surface antigens: M, T, R}

groupable streptococcistreptococci

•A, B and DA, B and D

–most important_{most important}

•C, G, F _{C, G, F}

–Rare_Rare

Non-groupable

Non-groupable

•S. pneumoniae_{S. pneumoniae}

–pneumonia _pneumonia

•viridans streptococciviridans streptococci

–e.g._e.g. S. mutans S. mutans

*dental _dental

caries

Lipoteichoic Acid and F-protein

Lipoteichoic Acid and F-protein

fibronectin

fibronectin

lipoteichoic acid

lipoteichoic acid

F-protein

F-protein

epithelial cells

M protein

M protein

•

major target

major target

– _{natural immunitynatural immunity}

•

strain variation

strain variation

– antigenicity_antigenicity

•

re-infection

re-infection

M protein

M protein

M protein M protein fibrinogen fibrinogen r r r peptidoglycan peptidoglycan r r r IgG IgG Complement

Complement IMMUNEIMMUNE

NON-IMMUNE

Hemolysis

alpha

beta

S

.

.

pyogenes (

pyogenes (

Group A)

Group A)

-suppurative

-suppurative

• _{affect all ages peak incidence at affect all ages peak incidence at}

5-15 years of age

5-15 years of age

• _{non-invasive non-invasive}

– _{pharyngitis pharyngitis}

– skin infection, impetigo_{skin infection, impetigo}

• _{invasive bacteremia invasive bacteremia}

– _{toxic shock-like syndrome toxic shock-like syndrome} – _{"flesh eating" bacteria"flesh eating" bacteria}

• Scarlet fever _{Scarlet fever}  _{rash rash}

 _{erythrogenic toxin erythrogenic toxin}

• rheumatic fever _{rheumatic fever}

 _{inflammatory diseaseinflammatory disease}  _{life threateninglife threatening}

 _{chronic sequalaechronic sequalae}  _{fever fever}

 _HeartHeart  _JointsJoints

 _{rheumatic NOT rheumatoid arthritisrheumatic NOT rheumatoid arthritis}

• Acute glomerulonephritis _{Acute glomerulonephritis}

immune complex disease of kidney

immune complex disease of kidney

Rheumatic fever -etiology Rheumatic fever -etiology

 _{M protein M protein}

– cross-reacts heart myosin _{cross-reacts heart myosin}

– autoimmunity_autoimmunity

 _{cell wall antigens cell wall antigens}

– poorly digested poorly digested in vivoin vivo

– persist indefinitely_{persist indefinitely}

Post-infectious diagnosis (serology)

Post-infectious diagnosis (serology)

• antibodies to streptolysin O_{antibodies to streptolysin O}

• important if delayed clinical sequelae _{important if delayed clinical sequelae}

occur

occur

• superantigen_superantigen

• T cell mitogen _{T cell mitogen}

• activates immune _{activates immune}

system

Group B streptococcus -

Group B streptococcus -

identification

identification

• _{neonatal meningitisneonatal meningitis}

• _{septicemiasepticemia} • transmission _transmission

– vaginal flora_{vaginal flora}

 _{ hemolysishemolysis}

• _{hippurate hydrolysishippurate hydrolysis} • _{CAMP reactionCAMP reaction}

Group D streptococcus

Group D streptococcus

• Growth on bile esculin agar_{Growth on bile esculin agar}

– black precipitate _{black precipitate}

• 6.5% saline_{6.5% saline}

• _growgrow

– _{enterococcienterococci} • no growth _{no growth}

Enterococci

Enterococci

• _{distantly related to other streptococcidistantly related to other streptococci} • _{genus genus EnterococcusEnterococcus}

• gut flora_{gut flora}

– _{urinary tract infection urinary tract infection}

• fecal contamination_{fecal contamination}

– _{opportunistic infectionsopportunistic infections}

• _{particularly endocarditisparticularly endocarditis}

• _{most common most common E. (S.) faecalisE. (S.) faecalis}

• resistant to many antibiotics _{resistant to many antibiotics}

– including vancomycin_{including vancomycin}

Viridans streptococci

Viridans streptococci

• _{diverse species diverse species}

• _{oral oral}

• dental caries_{dental caries}

 _{ hemolytic and negative for other tests hemolytic and negative for other tests}

• _{non-groupable.non-groupable.}

• includes _includes S. mutansS. mutans

– endocarditis _endocarditis

Streptococcus pneumoniae

S. pneumoniae - diplococci

• capsule: _capsule:

• pneumolysin_pneumolysin: :

• _{Surface protein adhesinand Surface protein adhesinand} secretory IgA protease.

secretory IgA protease.

• Teichoic acid and the _{Teichoic acid and the}

Peptidoglycan fragment,

Peptidoglycan fragment,

phosphorylchorine .

phosphorylchorine .

• leading cause pneumonia_{leading cause pneumonia}

– particularly young and old_{particularly young and old}

– after damage to upper _{after damage to upper} respiratory tract

respiratory tract

*e.g. following viral infection *e.g. following viral infection

• bacteremia_bacteremia

• meningitis_meningitis

GRAM POSITIVE COCCI

S. aureus

 hemolytic mannitol yellow

+

-Staphylococcus (Clusters) Streptococcus (pairs & chains) Catalase

• BETA: Bacitracin S .pyogenes (group A) CAMP/Hippurate S. agalactiae (group B)

Hemolysis Coagulase

S. epidermidis

nonhem olytic (usua lly) mannitol

white

(2) ALPHA: Optochin/Bile Solubility S. pneumoniae

• GAMMA: Bile Esculin 6.5% NaCl Group D* Enterococcus

Bile Esc ulin 6.5% NaCl Group D* Non-Enterococcus

(*can also be beta or alpha hemolytic)

Note: Strep. viridans

are alpha hemolytic and negat ive for all the tests below + + + + + + +

Streptex antiserum

Latex agglutination - streptococci

Quellung reaction Quellung reaction

• using antisera using antisera

• capsule "fixed" _{capsule "fixed"}

• visible microscopically_{visible microscopically}

Not optochin sensitive optochin sensitive

Prevention and Treatment

Prevention and Treatment

•

Immunity ; 14 capsule types mixed

Immunity ; 14 capsule types mixed

vaccine

vaccine

•

M

M

ost strains susceptible to

ost strains susceptible to

penicillin

penicillin

, but

, but

resistance is

resistance is

common

•

Gram negative _{Gram negative}

• _{diplococci (pairs of diplococci (pairs of}

cocci)

cocci)

• _{oxidase positiveoxidase positive}

• Culture: 5-10% CO_{Culture: 5-10% CO22}

• Thayer Martin. _{Thayer Martin.}

– _{selective selective}

– chocolate agar_{chocolate agar}

* _{heated bloodheated blood}

Capsule

LPS

N. meningitidis

Virulence Factors

Similar, but – Differences in utilization

Hemolysin IgA protease PILI

Opacity (OPA) proteins Outer Membrane Proteins

N. gonorrhoeae

LPS

PILI

Opacity (OPA) proteins Outer Membrane Proteins IgA protease

Neisseria gonorrhoeae

Using the Gram stain in patient specimens, the organisms are most often observed in polymorphonuclear leukocytes

Gram stain of pure culture Urethral exudate

• _{After 2-14 daysAfter 2-14 days}

•F_Found only in manound only in man

• _{GGonorrheaonorrhea: : second most common venereal second most common venereal}

disease

Pili = key in anchorage of organisms

to mucosal epithelium.

Nonpiliated gonococci are avirulent

Porin proteins (Por) = prevent phagolysosome fusion & allow intracellular survival [ also called protein I]

Opacity proteins (Opa) = binding of organisms to epithelium [also called protein II]

Reduction-modifiable proteins (Rmp) = protection against bactericidal antibodies [ also called protein III]

Neisseria gonorrhoeae

Bartholin’s Duct

Disseminated gonococcal infection (DGI).

Fever, polyarthritis

(or monoarticular septic arthritis), and/or dermatitis

(pustules on a hemorrhagic base).

Smear

Smear

• polymorphonuclear cell_{polymorphonuclear cell}

• Gram negative cocci_{Gram negative cocci}

many in cellsmany in cells

• Culture_Culture

•





lactamase-resistant cephalosporin

lactamase-resistant cephalosporin

–

e.g. ceftriaxone

e.g. ceftriaxone

•

resistant strains

resistant strains

–

common

common

–

produce

produce





lactamases

lactamases

–

destroy penicillin

destroy penicillin

Antibiotic therapy

N. meningitidis

Neisseria

Neisseria

meningitidis

meningitidis

• _{resides resides in man onlyin man only}

• usually sporadic cases _{usually sporadic cases}

– mostly young _{mostly young}

children

children

• outbreaks _outbreaks

– _{adults adults}

– crowded conditions _{crowded conditions}

* _{e.g. army e.g. army}

barracks

barracks

• _{1-4 1-4 daysdays}

• _{SSecond most common econd most common}

meningitis

meningitis

– _{pneumococcus, pneumococcus,}

most common

most common

• _{FFatal if untreated atal if untreated} • _{RResponds well to esponds well to}

antibiotic therapy

antibiotic therapy – penicillin penicillin

Upper respiratory

Upper respiratory

tract

tract infection infection

– _{adhesion pili adhesion pili}

Bloodstream

Bloodstream

Brain

Brain

Meningococcal

Meningococcal

meninigitis

Diagnosis

Diagnosis

• _{spinal fluid spinal fluid}

– Gram negative Gram negative diplococci

diplococci

within within

polymorphonuclear cells

polymorphonuclear cells

– _{meningococcal meningococcal}

antigens

antigens

• _{CultureCulture}

– Thayer Martin agarThayer Martin agar

• capsule_capsule

– _{inhibit phagocytosisinhibit phagocytosis}

• anti-capsular antibodies_{anti-capsular antibodies}

– stop infection_{stop infection}

• _{antigenic variationantigenic variation} – _{serogroupsserogroups}

• vaccine _vaccine

– multiple serogroups _{multiple serogroups}

Prevention