coagulase-negative & catalase- negative & aerobic

completely lyses RBC on blood agar around culture & leaving clear zone around culture

Microbiology TEST 1

Microbiology 4th Semester

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This flashcard set delves into university-level microbiology, focusing on infections, bacteria like streptococcus and staphylococcus, and their role in diseases. It covers virulence factors, cell structures, and clinical presentations, benefiting medical students and professionals seeking to understand bacterial infections and their impact on health.

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Staphylococcus Aureus is resistant to:

Drying / high temperatures

disinfectant

antiseptic solution

antimicrobials

low temperatures

Staphlococcus Aureus has 5 Cytolytic Toxins also known as membrane-damaging toxins, name two of them who don't belong to the superantigens:

hemolysin

P-V leukocidin (panton-valentine leukocidin)

exfoliative toxins (ETA,ETB)

TSST-1 (toxic-shock-syndrom-toxin-1)

enterotoxins

Staphylococcus Aureus has 5 cytolytic toxins name the 3 superantigens:

exfoliative toxins (ETA,ETB)

enterotoxin

TSST-1 ( toxic-shock-syndrome-toxin-1)

P-V leukocidin ( panton-valentine leukocidin)

Hemolysin

staphylococcus Aureus has superantigens that does what ?

unusually bacterial toxins that interact with exceedingly large amounts of T4 lymphocytes

this results in secretion of excessive amounts of cytokine IL-2 and the activation of self-reactive T-lymphocytes

don't interact

are harmless

bind to MHC II molecules of macrophages which in turn interact with T-cells

Staphylococcus aureus name the four types of Hemolysins, which are responsible for protection against hosts immune system.

alpha

beta

gamma

delta

epsilon

staphylococcus aureus diseases can be caused by

direct organ invasion / purulent

exotoxin release / toxin-mediated

endotoxin release / toxin-mediated

indirect organ invasion / purulent

Diseases caused by Staphylococcus Aureus by exotoxin release are:

TSS (toxic-shock-syndrom)

SSSS ( staphylococcus-scalded-skin-syndrome)

Food poisoning

Pneumonia

Skin & Wound infection

Diseases caused by Staphylococcus Aureus by direct organ invasion or purulent/pyogenic are:

pneumonia

endocarditis

skin & wound infection

bacteremia

TSS & SSSS

SSSS - staphylococcus (aureus)-scalded-skin-syndrome:

caused by exotoxin release of exfoliative toxins

primarily in neonates and young children

characteristic perioral erythema ( redness and inflammation around mouth)

caused by TSST-1

bullous impetigo, carbuncles, folliculitis, furuncles - spread over entire body

SSSS disease in Staphylococcus aureus also named?

Ritter's Disease (causes desquamation of epithelium)

TSS - toxic-shock-syndrome in Staphylococcus Aureus:

caused by TSST-1

caused by Exfoliative Toxins (ETA,ETB)

site of infection is vagina or wound and released to blood stream

Fever,watery diarrhea, nausea, vomiting, desquamation of palms and soles, diffuse erythematous rash

septic shock -hypotension and severe organ system damage

Food poisoning in Staphylococcus Aureus is a exotoxin mediated disease

caused by enterotoxins

complication enterocolitis

food contaminated by sneezing or contaminated hands

food contains bacteria causing infection

rather intoxication due to toxins present in food

Food poisoning of Staphylococcus Aureus is exotoxin-mediated disease:

has rapid onset of disease 4h

last less than 24h

severe vomiting, watery diarrhea, abdominal cramps

processed meats like ham/salted pork, ice cream, potato salad

caused by bacteria in Food

Direct organ invasion caused by staphylococcus results in :

Pneumonia,
Acute Endocarditis,
Skin & Wound Infection,
Bacteremia,
Septic Arthritis
Meningitis
Osteomyelitis

Wound Infection - postoperative or posttraumatic

acute endocarditis - severe infection of heart valves due to rapid growth and embolism to brain/lungs

osteomyelitis - in children under 12

pneumonia - severe & in hospitalized patients with prior viral influenza/ flu

skin infection - also caused by streptococcus pyrogens

Direct organ invasion caused by staphylococcus results in :

Pneumonia,
Acute Endocarditis,
Skin & Wound Infection,
Bacteremia,
Septic Arthritis
Meningitis
Osteomyelitis

Septic Arthritis - painful red swollen joint & decreased range of motion

Skin infection- bullous impetigo, carbuncle, furuncles, folliculitis

Septic Arthritis - in pediatric aged groups and adults over 50

pneumonia - is not severe and doesn't cause cavitation in the lungs

blood & catheter infections -migrate from skin along catheter - cause bacteremia, septic shock & endocarditis

Cutaneous Infections - Skin Infections in staphylococcus are pyogenic (pus forming)

Impetidgo
Carbuncle
Furuncles
Folliculitis

Carbuncle - are deeper and can cause systemic diseases -fever,chills, bacteremia

Folliculitis - infection of hair follicle

Impetidgo - can also me indicator for (GAS) Streptococcus pyogenes

furuncles -cause systemic disease

furuncles - raised nodules

Acute Endocarditis caused by staphylococcus aures can

can be severe and rapid onset

rapid growth of vegetation on heart valve, causing valvular destruction

slow growth & less severe

high mortality

embolism can spread to lungs causing pneumonia

Staphylococcus Epidermidis :

is coagulase-negative

has a biofilm - protects from antibiotics and host defenses

has a biofilm - allows adhesion to prosthetic devices

is less severe

is endogenous - on skin

Staphylococcus Epidermidis can cause

endocarditis of artifical devices

bacteremia

due to virulence factor - slime layer/ biofilm /lipase

due to virulence factor - capsule

endocarditis - causes valvular destruction

Staphylococcus Saprophyticus

is Coagulase-negative

endogenous - of vagina

endogenous - of skin

virulence factor is urease

infects young, sexually active woman

Staphylococcus Saprophyticus causes

bacteremia

urinary tract infection

dysuria (pain on urination)

pyuria ( pus in urine)

frequent cause of cystitis in woman

How many species are known from streptococci and how many are from significance?

20 are known

10 are known

30 are known

5 are significant

3 are significant

Streptococci are

coagulase-negative

catalase- negative

coagulase- positive

catalase- positive

aerobic

Streptococci are devided into three groups known as

alpha hemolytic

beta hemolytic

gamma hemolytic

delta hemolytic

epsilon hemolytic

alpha hemolytic

partially lyses RBC on blood agar around culture

completely lyses RBC on blood agar around culture

leaving greenish discoloration

leaving clear zone

not lysing at all RBC

beta hemolytic

partially lyses RBC on blood agar around culture

completely lyses RBC on blood agar around culture

leaving greenish discoloration around culture

leaving clear zone around culture

not able to lyses RBC at all

streptococcus pyogenes is

Lancefield group A antigen

Lancefeld group B antigen

beta-hemolytic

alpha-hemolytic

pus producing

Beta-Hemolytic Streptococci are:

streptococcus pyogenes

streptococcus agalactiae

streptococcus viridans

streptococcus pneumoniae

enterococci

alpha-hemolytic streptococci are:

1. Streptococcus pyogenes

2. Streptococcus agalactiae

3. Streptococcus viridians

4. Streptococcus pneumoniae

5. Enterococci (S. faecalis, S.Faecium)

Posessing Alpha-,beta-,gamma-hemolytic which streptococci ?

2. Streptococcus agalactiae

1. Streptococcus pyogenes

3. Streptococcus viridians

4. Streptococcus pneumoniae

5. Enterococci (S. faecalis, S.Faecium)

Lancefield Group antigens are

virulence factors of streptococci

not virulence factors of streptococci

used for distinguishing from other ß-hemolytic streptococci

used for comparing all hemolytic streptococci

Virulence Factors of CELL WALL of Streptococcus Pyogenes

M-protein

Hyaluronic acid capsule

polypeptide capsule

Lipoteichoic acid

F protein

Which virulence factors of the cell wall of streptococci pyogenes are responsible for adhesion to host cell?

M-protein

F-protein

Lipoteichoic acid

Hyaluronic acid capsule

C Carbohydrate antigen

Which virulence factors of the cell wall of streptococci pyogenes are responsible for protection of phagocytosis of host cell?

hyaluronic acid capsule

M-protein

F-protein

C Carbohydrate antigen

Lipoteichoic acid

Which virulence factors of the cell wall of streptococcus pyogenes can invade epithelial cells of host?

M-protein

F-protein

Hyaluronic acid capsule

Lipoteichoic acid

Does Streptococcus pyogenes have Superantigens?

yes

Name superantigen of streptococcus pyogenes:

TSST-1

Exfoliative toxins

Enterotoxins

Erythrogenic toxin

pyogenic streptococcal exotoxin

Streptococcus Pyogenes Superantigen causes

severer infections of streptococcus pyogenes

necrotising fasciitis

TSS

Scarlet fever

SSSS

Streptococcus Pyogenes Superantigen has how many toxins?

A,B,C and F

A,B,C and D

they are heat-labile

they are heat-stable

they excessively secret cytokines

Streptococcus pyogenes superantigen is known as PSE - pyrogenic streptoccocal exotoxin but was earlier named

erythrogenic toxin

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