Staphylococcus

Staphylococcus

Gram (+) cocci arranged in grapelike clusters

Non-motile organisms

Non-encapsulated

Non-spore formers

Aerobic

Facultative anaerobes

Strongly catalase (+)

*STAPHYLE*

bunch of grapes

*COCCUS*

grains or berries

Staphylococcus saprophyticus

Staphylococcus Can ferment glucose except for

*Micrococcus pyogenes variety aureus*

Staphylococcus aureus is formerly called

Staphylococcus aureus

AUREUS

GOLDEN YELLOW PIGMENT

Catalase (+)

Coagulase (+)

Mannitol (+)

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Inhabits anterior nares, nasopharynx, perineal area, skin,

Colonizer of mucosa·         GOLDEN YELLOW PIGMENT

GOLDEN YELLOW PIGMENT

Soluble in ether and alcohol and is termed as LIPOCHROME

carotenoid

GOLDEN YELLOW PIGMENT is due to ______ and is variable ranging from deep orange to pale yellow

Endogenous strain

sterile site by traumatic introduction during surgery or microabrasions

Enterotoxin A and D

Staphylococcus aureus Enterotoxin

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Associated with food poisoning

Enterotoxin B

Staphylococcus aureus

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associated with nosocomial infection

Enterotoxin F / Exotoxin C / Pyrogenic exotoxin / TSST-1

Produced by S. aureus phage group 1

Causes Toxic Shock Syndrome

Responsible for Staphylococcal Scarlatinae Syndrome

Exfoliative Toxin / Epidermolytic Toxin

Produced by *S. aureus phage group II*

Causes Scalded Skin Syndrome (SSS)

Protein A

Differentiates pathogenic staphylococci from non-pathogenic staphylococci

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Aids the bacterium to avoid phagocytosis by interfering with opsonization

B

Non-pathogenic staphylococci has protein ___ in cell wall

Alpha Toxin

Attacks macrophages and platelets but not monocytes

Alpha hemolysin

serves as index of virulence

Beta Toxin

Can produce “hot-cold” lysis which enhances hemolytic activity if incubation at 37°C is followed by 4°C or at room temperature

Delta Toxin

Attacks RBC, macrophages, lymphocytes, neutrophils and platelets

Gamma Toxin

Suggestive for a possible role in the state of staphylococcal bone disease

Panton-Valentine Leukocidin

Attacks polymorphonuclear cells and macrophages

Coagulase

Catalase

Gelatinase

Phosphatase

Lipase

Enzymes of Staphylococcus Aureus

Nuclease

heat resistant, heating at 65°C causes structural disruptions but changes are reversible

Staphylokinase

Responsible for lysis of clot

fibrinolysin

Staphylokinase is also known as

Hyaluronidase

Spreading factor

Hydrolysis of hyaluronic acid in the tissue

Folliculitis

inflammation and infection of hair follicles

Boils / Furuncles

lesions of folliculitis developed into a deeper inflammatory nodule

Carbuncle

abscess that extends even more deeply into the subcutaneous fat and may have multiple draining sites

Impetigo

pustules are larger and surrounded by a small zone of erythema compared to strep impetigo, highly contagious

Food Poisoning

Caused by enterotoxins A & D, short incubation period

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S. aureus produces enterotoxins while growing in meat, dairy or bakery products.

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Enterotoxins are absorbed in the GIT

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Vomiting results within hours but diarrhea is less frequent

Toxic Shock Syndrome (TSS)

Caused by phage group I producing TSST-1

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Multi-system disease characterized by high fever, hypotension, shock and rash

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Associated with tampon use but may also be seen in males and non-menstruating females

Scalded Skin Syndrome (SSS) / Ritter Disease / Lyell’s Syndrome

Exfoliative dermatitis caused by phage group II

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More common in newborns and adults with chronic renal failure and impaired immune system

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Toxic epidermal necrolysis

Ritter Disease / Lyell’s Syndrome

Scalded Skin Syndrome (SSS) can also be referred to as

Staphylococcus epidermis

Associated with hospital-acquired infections

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Causes prosthetic valve endocarditis

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May cause septicemia in immunocompromised patients

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Most common cause of HA-UTI

slime

enables Staphylococcus epidermis to adhere to the surface of prosthetic devices

Staphylococcus saprophyticus

Associated with UTI among young sexually active females

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Adheres to the urogenital tract

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Rarely found in other skin areas and mucous membranes

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Even low numbers in urine culture are considered significant

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Second most common cause of UTI next to Escherichia coli

Staphylococcus citreus

lemon yellow pigment

Staphylococcus albus /epidermidis

porcelain white pigment

Staphylococcus intermedius, Staphylococcus pseudointermedius, Staphylococcus delphini

associated with skin infections in dogs as well as invasive infections in immunocompromised humans as a result of a bite or scratch wound

Staphylococcus haemolyticus

Staphylococcus lugdunensis

associated with implantation of medical devices resembling Staphylococcus aureus infections

yellow, reddish or pink

Mannitol Sugar Agar

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S. aureus appear as _____ colonies while S. epidermidis appear as ---- colonies

Tellurite Medium

jet black colonies

Vogel Johnson Agar, Chapman Stone Agar

Isolation Medium

Small Colony Variants (SCVs)

small pinpoint, non-hemolytic and non- pigmented colonies on blood agar

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Due to limited nutrients or other selective pressures

*uniform turbidity*

Staphylococcus In broth, produces

Catalase Test

Presumptive Test

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differentiates Staphylococci from Streptococci

3% H2O2

For Catalase Test

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·         drop of ___ on a slide + organism

Coagulase Test

Confirmatory Test

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Best single criterion of pathogenicity of Staphylococcus aureus

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differentiates S. aureus from CONS

yellow zones around the colonies

Mannitol Fermentation Test (+) for staphylococcus aureus

Mannitol Fermentation Test

Pathogenic strains of Staphylococcus aureus ferments mannitol and tolerates high concentration of salt which is 7.5% - 10% NaCl

Modified Oxidase Test (Microdase)

Differentiates CONS from Micrococcus

purple in 30 seconds

Modified Oxidase Test (Microdase)

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(+)

Tetramethyl –p - phenylenediamine dihydrochloride + dimethyl sulfoxide (DMSO)

Modified Oxidase Test (Microdase)

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reagent

S. saprophyticus

resistant to novobiocin

S. aureus and S. epidermidis

sensitive to novobiocin

Lysostaphin Sensitivity

1:10 dilution of culture is exposed to 2 microorganisms of Lysostaphin for 30 minutes at 37°C

reduction of 90% or more in number of organisms

Lysostaphin Sensitivity

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(+)

Staphylococcus

More resistant to adverse environmental conditions

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Survives for weeks in dried pus and sputum

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On sealed agar slants, remains viable for several months

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More resistant than most bacteria to common disinfectants like *phenol* and *mercuric chloride*

*60°C for 1 hour*

Most strains Staphylococcus are heat resistant and can be killed at