Module 4.1 Staphylococcaceae and Micrococcus Flashcards
Staphylococcus belongs to family:
Staphylococcaceae
How many species does Staphylococcus bacteria have?
45 species
How many subspecies does Staphylococcus abcteria have?
21
Three Staphylococcus bacteria most commonly seen in human infections
- S. aureus
- S epidermidis
- S. saprophyticus
gram staining of Staphylococcus
gram positive
diameter of Staphylococcus
0.5 - 1.5 um
motility of Staphylococcus
non-motile
T or F: Staphylococcus is a spore forming bacteria
false
It is non-spore forming
oxygen requirement of Staphylococcus
facultative anaerobe
Staphylococcus:
catalase positive or negative?
catalase-positive
temperature requirement of Staphylococcus
37 degrees C
osmotic pressure of Staphylococcus
halotolerant
T or F: Staphylococcus is fermentative
True
Staphylococcus is fermentative.
Staphylococcus:
nitrate reduction, +/- ?
+
Three additional characteristics of Staphylococcus
Coagulase (+)
DNase (+)
Mannitol fermenter
T or F: Staphylococcus is not a part of normal human microflora.
False
Staphylococcus is a part of normal human flora.
Staphylococcus is most commonly present in what part of the human body
anterior nares (nostrils)
what percentage of adults have Staphylococcus in the anterior nares
20-40%
Staphylococcus is carried by normal individuals _____ rather than chronically
intermittently
4 other sites in the human body that Staphylococcus colonize
- nasopharynx
- perineum
- axillae (armpit)
- vagina
most common mode of Staphylococcus transmission
contaminated hands
Though Staphylococcus is part of the normal human flora, it is able to cause _________ under appropriate conditions
opportunistic infections
Though Staphylococcus is part of the normal human flora, it is able to cause _________ under appropriate conditions
opportunistic infections
6 factors that predispose an individual to serious S. aureus infections.
- breaks in continuity of mucosal and cutaneous surface
- foreign bodies or implants
- prior infection (viral influenza)
- defect in immunity
- chronic diseases
- antimicrobial administration
3 kinds of diseases caused by Staphylococcus aureus
- cutaneous diseases
- toxigenic diseases
- systemic diseases
5 cutaneous staphylococcal diseases
- Folliculitis
- Hidradenitis suppurativa
- Furuncle
- Carbuncle
- Impetigo
Staphylococcal infections are pus-forming or _____
pyogenic
All Staphylococcal infections are _____
abscesses
Staphylococcal infections of the skin occur through: (3)
- wounds
- follicles
- skin glands
What is an abscess?
inflamed, fibrous lesion enclosing a core of pus
mild inflammation of the superficial dermis that is restricted to the hair follicles
Folliculitis
term for opening of the hair follicles
ostia
folliculitis is characterized by:
- small, reddish, painful lesions
2. absence of systemic symptoms
If folliculitis occurs in the eyelid, it is referred to as ___
stye
If folliculitis occurs in the eyelid, it is referred to as ___
stye
It is a chronic/relapsing inflammation. It is not a primarily a staphylococcal disease, but is complicated by S. aureus
Hidradenitis suppurativa
Hidradenitis suppurativa usually involves areas that bear:
apocrine glands
4 sites where Hidradenitis suppurativa most commonly appear
axillae
groin
perineal and perianal regions
Hidradenitis suppurativa is associated with blocked and infected____
apocrine sweat glands
Hidradenitis suppurativa is associated with blocked and infected____
apocrine sweat glands
Hidradenitis suppurativa is associated with presence of multiple lesions caused by blocked and infected____
apocrine sweat glands
Hidradenitis suppurativa is characterized by the presence of __, __, __, and absence of __
local pain
swelling
erythema
systemic symptoms
It is a deeper seated infection of the hair follicles
furuncle
furuncle is latin for:
little thief
another term for furuncle
boils
In furuncles, the inflammation of single hair follicle/ sebaceous gland progresses into a ______
large, red, extremely tender abscess or pustule
term for when furuncles appears in clusters
furunculosis
4 common sites for furuncles
buttocks
breasts
axillae
back of the neck
larger and deeper lesion which is created by aggregation & interconnection of furunculosis
carbuncle
characteristics of carbuncle
- extremely painful
- can be fatal in elderly when it gives rise to systemic disease
carbuncle is latin for
little coal
where are carbuncles mostly found
tough skin (back of the neck)
cutaneous disease that is not confined to follicles and skin glands
impetigo
impetigo is latin for:
to attack
characteristics of impetigo
- bubble like epidermal sweeping
- can break and peel away like localized scalding skin syndrome
impetigo is usually present in exposed areas like:
face
impetigo may spread to other areas through:
autoinoculation
two types of impetigo
- non-bullous
2. bullous
impetigo that begins as single red macule (patch) or papule, which quickly becomes a vesicle that ruptures & forms an erosion
non-bullous
most common type of impetigo (70%)
non- bullous
impetigo that is a localized form of scalded skin syndrome and commonly affects neonates
bullous
impetigo where the lesion dries to form a honey-colored crusts w/ erythematous (reddish) margins
non-bullous
impetigo which has oozing yellow crust but has no surrounding erythema
bullous
impetigo that is usually found in moist intertriginous areas (diaper area, axillae, neck folds)
bullous
impetigo that may be pruritic (itchy)
non-bullous
3 types of staphylococcal toxigenic diseases
- staphylococcal food poisoning
- staphylococcal scalded skin syndrome
- staphylococcal toxic shock syndrome
gastrointestinal illness that is caused by eating food contaminated w/ S. aureus toxin
Staphylococcal food poisoning
Staphylococcal food poisoning acute symptoms appear within _____ of ingestion
2-6 hours
Staphylococcal food poisoning recovery occurs within ___
24 hours
two symptoms of Staphylococcal food poisoning
- emesis (vomiting often projectile)
- diarrhea (less frequent)
disease associated w/ handling or unrefrigerated custards, sauces, cream pastries, processed meats, chicken salad, ham
Staphylococcal food poisoning
T or F: Staphylococcal food poisoning cannot happen with salt preserved food.
False
Staphylococcus is halotolerant.
T or F: Staphylococcus toxins do not alter food taste or smell.
True
T or F: Staphylococcal food poisoning is a food-borne infection
False
food intoxication
causes widespread erythema and separation of the dermis from the epidermis which results into exposure of large areas of denuded and raw skin
Staphylococcal Scalded Skin Syndrome
another term form Staphylococcal Scalded Skin Syndrome
Ritter’s disease
Staphylococcal Scalded Skin Syndrome is usually seen in
neonates (less than a month old) children less than 5 years
appears as bullous lesions over large areas of the body
Staphylococcal Scalded Skin Syndrome
Staphylococcal Scalded Skin Syndrome symptoms wane over ____
5-7 days
resembles sunburns followed by skin desquamation and involvement of multiple organ systems
Staphylococcal toxic shock syndrome (TSS)
symptoms of Staphylococcal toxic shock syndrome (TSS)
initially flu-like
fever
hypotension
skin rash
desquamation occurs in Staphylococcal toxic shock syndrome after __
1-2 weeks
some symptoms associated with Staphylococcal toxic shock syndrome
vomiting diarrhea renal failure headache, chills sore throat conjunctivitis
diseases associated w/ use of high-absorbency tampons
Staphylococcal toxic shock syndrome
most common pattern of staphylococcal infections
focal
local cutaneous to other sites
three kinds of miscellaneous systemic infections caused by staphylococcus
- osteomyelitis
- pneumonia
- bacteremia
Bone infection caused by staphylococcus
Osteomyelitis
staphylococcus infection that usually occurs after influenza viral infections
pneumonia
three consequences of bacteremia
Endocarditis
Arthritis
Meningitis
promotes colonization of, spread in, or damage to host tissues, enhance survival within cells
Virulence factors
consists of polysaccharides which mediates attachment to host cells or tissues
microcapsule
inhibits phagocytosis by polymorphonuclear leukocytes unless specific antibodies are present
microcapsule
can only be visualized through electron microscope
microcapsule
microcapsule has how many serotypes
11
microcapsule serotype which is responsible for majority of infections
type 5 and type 8
tagging of foreign pathogens using opsonin for elimination by phagocytes, without which negatively charged pathogen and phagocyte would repel each other
opsonization
bacterial surface protein found in some S. aureus strains which prevents opsonization
protein A
mechanism of protein A
a. protein A binds to Fc portion of IgG
b. IgG is no longer capable of binding to Fc receptor on phagocyte
c. no opsonization
blocks complement fixation
protein A
inactivates toxic hydrogen peroxide and free radicals
catalase
primary killing mechanism of phagolysosome
myeloperoxidase system
forms toxic hydrogen peroxide & free radicals
myeloperoxidase system
coats the bacterial cells, hiding their antigenic surface, thus protecting them from phagocytosis and immune response.
fibrin
promotes conversion of fibrinogen to fibrin causing plasma to clot
coagulase
hydrolyzes DNA, facilitating the spread of bacteria by liquefying abscess materials.
DNase
known as the “spreading factor
hyaluronidase
hydrolyzes the intercellular
matrix of acid mucopolysaccharides in tissue, spreading the organism to adjacent areas
Hyaluronidase
hydrolyzes lipids
lipase
helps spread the organism in cutaneous and
subcutaneous tissues.
lipase
plasminogen activator
Staphylokinase
dissolves fibrin clot (fibrinolysis) which might aid in the spread of infection to contiguous tissues
Staphylokinase
makes tissues more susceptible to damage and destruction through complement activation
Phosphatidylinositol-specific phospholipase C
under plasmid-control and transmitted through transduction and conjugation
β-lactamase
provides resistance to β-lactam antibiotics such as penicillin, penicillin derivatives (penams), and cephalosporins.
β-lactamase
four-atom ring that is common to the molecular structure of some antibiotics
β-lactam
the β-lactamase breaks the β-lactam ring open through:
hydrolysis
lyse red blood cells by disrupting their cell membranes
hemolysins
damage cell membranes of neutrophils and macrophages, causing them to lyse.
Leukocidins
Hemolysins and Leukocidins are together referred to as:
Blood Cell Toxins
toxins that help incapacitate the host’s phagocytic line of defense
Blood Cell Toxins
5 blood cell toxins
⍺ (alpha)-Hemolysin β (beta)-Hemolysin δ (delta)-Hemolysin γ (gamma)-Hemolysin Panton-Valentine Leukocidin (PVL)
heterogeneous protein which forms pores on target cell membrane so monovalent cations pass leading to osmotic swelling and cell rupture
⍺ (alpha)-Hemolysin
potent toxin which lyses RBCs
and damages monocytes, macrophages, lymphocytes, skeletal muscle, heart, and renal tissue
⍺ (alpha)-Hemolysin
active against thrombocytes (platelets)
⍺ (alpha)-Hemolysin
contribute to septic thrombotic
events during S. aureus bacteremia.
⍺ (alpha)-Hemolysin
protein exotoxin that acts as sphingomyelinase degrading
sphingomyelin in the cell membrane
β (beta)-Hemolysin
toxic for many kinds of cells
β (beta)-Hemolysin
β (beta)-Hemolysin is also referred to as
“hot-cold”
its hemolytic properties are enhanced by subsequent exposure of RBCs to low temperatures.
β (beta)-Hemolysin
encodes β (beta)-Hemolysin
lysogenic bacteriophage
β-hemolysin is cytotoxic not only to human erythrocytes but as well as to:
monocytes
Cell death from β-hemolysin result from disruption of host cell’s __
plasma membrane fluidity
β-hemolysin is said to
be inactive against : 3
granulocytes
lymphocytes
fibroblasts.
small peptide that acts primarily as a surfactant or a detergent-like molecule
δ (delta)-Hemolysin
interacts with cell membranes and forms channels resulting in slow leakage of cellular contents.
δ (delta)-Hemolysin
It may have a role in S. aureus diarrheal diseases.
δ (delta)-Hemolysin
leukocidin that lyses WBCs and composed of two proteins
γ (gamma)-Hemolysin
two proteins of γ (gamma)-Hemolysin
S and F
Affected cells undergo degranulation of the cytoplasm, cell swelling, and lysis.
γ (gamma)-Hemolysin
leads to massive release of inflammatory mediators which are responsible for necrosis and severe inflammation.
γ (gamma)-Hemolysin
cells affected by γ (gamma)-Hemolysin undergoes
degranulation of the cytoplasm
cell swelling
lysis
produced by lysogenized strains
of S. aureus
Panton-Valentine Leukocidin (PVL)
active against neutrophils and
causes tissue necrosis
Panton-Valentine Leukocidin (PVL)
also consists of S and F proteins that act on WBC
Panton-Valentine Leukocidin (PVL)
Three pore-forming blood cell toxins
⍺ (alpha)-Hemolysin
γ (gamma)-Hemolysin
Panton-Valentine Leukocidin (PVL)
superantigen found in about 20%
of S. aureus isolates.
Toxic Shock Syndrome Toxin (TSST-1)
epidermolytic toxins that cause the intraepithelial splitting of cellular linkages seen in SSSS
Exfoliative toxins (or exfoliatins)
the dissolution of this part of the skin results in the manifestation of SSSS
mucopolysaccharide matrix of the stratum granulosum in the epidermis
two distinct proteins of the same
molecular weight
Exfoliative toxin A (ET-A)
Exfoliative toxin B (ET-B)
Exfoliative toxins that is plasmid-mediated.
ET-B
Exfoliative toxins produced by lysogenized strains of S. aureus;
ET-A
heat-stable exotoxins which are responsible for the clinical features of staphylococcal food poisoning.
Enterotoxins A-E, G-J, K-R, U, V
heat requirement to inactivate staphylococcal enterotoxins
100oC for at least 30 minutes
Clothes and bedding that may cause reinfection should be dry-cleaned at what temperature
70°C or higher
used in showering for adults to increase the bactericidal activity of the skin
chlorhexidine or hexachlorophene
used for persons found to be a source of an outbreak
nasal creams(mupirocin, neomycin, and bacitracin)
oral therapy (rifampin, ciprofloxacin)
effective in surgical procedures such as hip and cardiac valve
replacements
Chemoprophylaxis
given during and shortly
after surgery to reduce intraoperative infection and minimize superinfection
Methicillin
a cephalosporin
vancomycin
The most commonly encountered staphylococcal species
Staphylococcus epidermidis
S. epidermidis characteristics different to S. aureus
Coagulase(-)
DNase(-)
Non-mannitol fermenter
Comprises 99% of the normal flora of the skin
Staphylococcus epidermidis
Considered opportunistic pathogens, but are substantially less virulent than S. aureus
Staphylococcus epidermidis
Staphylococcus epidermidis is associated mainly with
nosocomial infections due to contaminated medical devices
associated with prosthetic heart valves; also pacemaker wires, implanted defibrillators, and vascular grafts
Endocarditis
associated with prosthetic joint, or hip implant
Arthritis
associated with indwelling urinary catheters
Urinary tract infection (UTI)
associated with IV catheters
Bacteremia
pathogenesis of Staphylococcus epidermidis
adherent slime forming biofilm on prosthetic devices
characteristics of S. saprophyticus that are dofferent from S. aureus
- Coagulase(-)
- DNase(-)
- Urease (+)
- Mannitol fermentation (variable)
primary site of S. saphrophyticus colonization in humans
gastrointestinal tract (primarily the rectum)
S. saprophyticus is alao part of the normal flora of :
genitourinarinay tract (urethra cervix) perineum
most common cause of community acquired UTI in young sexually active females
E. coli
second most common cause of community acquired UTI in young sexually active females
S. saprophyticus
pathogenesis of S. saprophyticus
production of adherent slime and urease
an enzyme that hydrolyzes urea in urine resulting in the formation of ammonia and ammonium carbonate, making the urine alkaline and favoring bacterial growth
urease
often resemble and ,therefore, are easily confused with staphylococci.
Micrococcus
habitat of micrococcus
free-living environments such as air, soil, various extreme environments and food
extreme environments that serve as habitats for Micrococcus
marine sediment
deep sea mud
activated sludge
most common foods where S. saprophyticus is present
fermented seafood
Micrococcus is considered a normal microbiota of the human ___
skin
mucosa
oropharynx
micrococcus infections likely involve :
endogenous strains
not generally identified to species level in clinical laboratories because they are rarely clinically significant
micrococci
gram staining of micrococci
gram positive
morphology of micrococci
tetrads
size of micrococci
0.5 -3.5 µm
micrococci that produces yellow colonies which may be mistaken for S. aureus
M. luteus
micrococci that produce reddish colonies
M. roseus
