(Lecture) Staphylococcus and Micrococcus Flashcards
Most cocci are Gram positive EXCEPT:
Neisseria
Moraxella
Veillonella
Most bacilli are Gram Negative EXCEPT:
Bacillus
Bifidobacterium
Actinomyces
Nocardia
Streptomyces
Clostridium
Corynebacterium
Erysipelothrix
Listeria
Lactobacillus
List down the Genus under the family Micrococcaceae:
Micrococcus
Staphylococcus
Stomatococcus
Planococcus
List down the Genus under the Family of Streptococcaceae:
Streptococcus
Enterococcus
Aerococcus
Leuconcoccus
Gemella
Pediococcus
A biological kingdom that is made up of prokaryotes, particularly bacteria.
Monera
The genus name Staphylococcus is derived from the Greek word _____, meaning branches of grapes.
Staphle
The genus name Staphylococcus is derived from the Greek word Staphle, meaning _____.
Branches of Grapes
Staphylococci are members of the newly formed family _____
Staphylococcaceae
Staphylococcus spp. contains _____ defined species, and _____ are found in man.
33
20
Species of staphylococci are initially differentiated by the coagulase test and are classified into two groups which are the:
Coagulase-positive Staphylococci
Coagulase-negative Staphylococci
Describe the colonies of S. aureus under Coagulase-positive Staphylococci
Golden-yellow colonies; Pathogenic
Describe the colonies of S. aureus under Coagulase-negative Staphylococci
Lemon yellow colonies; Chromogenic opportunistic pathogen
Describe the colonies of S. epidermidis under Coagulase-negative Staphylococci
Predominant normal flora on the skin; Leading cause of iatrogenic infection
Describe the colonies of S. citreus under Coagulase-negative Staphylococci
White pigment; Chromogenic opportunistic pathogen
Describe the colonies of S. saprophyticus under Coagulase-negative Staphylococci
Opportunistic pathogen; Normal flora of skin; Frequently cause UTI, abortion, miscarriages
Is Staphylococci gram-positive or gram-negative?
Gram-positive
Is Staphylococci catalase-positive or catalase-negative?
Catalase-positive
Staphylococci are aerobic or facultatively anaerobe except for _____ which is an obligate anaerobe
Staphylococcus saccharolyticus
Staphylococci are aerobic or facultatively anaerobe except for Staphylococcus saccharolyticus which is _____
Obligate anaerobe
Describe the colonies of Staphylococci:
Colonies are medium sized (4 to 8 mm) and appear cream-colored, white or rarely light gold, and “buttery-looking”
Hemolysis pattern of some Staphylococci species when grown under Blood Agar Plate
Beta-hemolytic
Rare strains of staphylococci are fastidious requiring _____, _____, _____ for growth
Carbon dioxide
Hemin
Menadione
So-called small colony variants of Staphylococci grow on media containing blood, forming colonies about _____ the size of wild-type strains after at least 48 hours of incubation.
1/10
So-called small colony variants of Staphylococci grow on media containing blood, forming colonies about 1/10 the size of wild-type strains after at least _____ of incubation.
48 hours
Is Staphylococcus aureus coagulase-positive or coagulase-negative?
Coagulase-positive
List down the CoNS that are Novobiocin Susceptible:
Staphylococcus epidermidis
Staphylococcus capitis
Staphylococcus haemolyticus
Staphylococcus hominis subsp. hominis
Staphylococcus lugdunensis
Staphylococcus saccharolyticus
Staphylococcus warneri
List down the CoNS that are Novobiocin Resistant:
Staphylococcus cohnii
Staphylococcus kloosii
Staphylococcus saprophyticus
Staphylococcus xylosus
Staphylococci species that are mistaken as coagulase-positive staphylococci because of the presence of clumping factor
Staphylococcus lugdunensis
Staphylococcus schleiferi
These are the substances that destroy the red blood cell liberating hemoglobin.
Hemolysin
_____ in addition to lysine erythrocytes it can also damage that platelets and macrophages and can cause severe tissue damage.
Alpha Hemolysis
Alpha hemolysis in addition to _____ it can also damage that platelets and macrophages and can cause severe tissue damage.
Lysine erythrocytes
Beta hemolysin also known as the _____ acts on the sphingomyelin in plasma membrane of erythrocytes and is also called as the hot cold lysine
Sphingomyelinase C
_____ also known as the Sphingomyelinase C acts on the sphingomyelin in plasma membrane of erythrocytes and is also called as the hot cold lysine
Beta-hemolysin
Beta-hemolysin also known as the Sphingomyelinase C acts on the sphingomyelin in plasma membrane of erythrocytes and is also called as the _____
Hot cold lysine
What virulence factor of Staphylococcus aureus ruptures the WBCs
Panton-Valentine Toxin/Leukocidin
Virulence factor of Staphylococcus aureus that is responsible for the manifestations of staphylococcal food poisoning, 2-6 hours after consuming contaminated food containing pre-formed toxin.
Enterotoxins
Enterotoxins are heat stable at what time and temperature?
100 degree Celsius for 30 Minutes
Toxic Shock Syndrome Toxin-1 is formerly known as _____ and _____
Enterotoxin F
Pyrogenic Exotoxin C
_____ is formerly known as Enterotoxin F and Pyrogenic Exotoxin C
Toxic Shock Syndrome Toxin-1
Cause of Toxic Shock Syndrome Toxin-1:
Toxic Shock Syndrome
The enterotoxins and TSST-1 belong to a class of polypeptides known as _____ which are potent activators of T lymphocytes leading to the release of cytokines such as interleukins and tumor necrosis factor.
Superantigens
The enterotoxins and TSST-1 belong to a class of polypeptides known as superantigens which are potent activators of _____ leading to the release of cytokines such as interleukins and tumor necrosis factor.
T lymphocytes
The enterotoxins and TSST-1 belong to a class of polypeptides known as superantigens which are potent activators of T Lymphocytes leading to the release of cytokines such as _____ and _____.
Interleukins
Tumor Necrosis Factor
Epidermolytic Toxin is also known as _____ or _____
ET
Exfoliatin
Responsible for the staphylococcal scalded skin syndrome (SSSS)
Epidermolytic Toxin
Epidermolytic Toxin that is considered as heat-stable
Exfoliative Toxin A
Epidermolytic Toxin that is considered as heat-labile
Exfoliative Toxin B
A Virulence Factor of Staphylococcus aureus that is responsible for lysine clot
Fibrolysin/Staphylokinase
Fibrolysin/Staphylokinase activates _____ to form plasmin which digests the vibrant clots
Plasminogen
Fibrolysin/Staphylokinase activates plasminogen to form _____ which digests the vibrant clots
Plasmin
Virulence Factor of Staphylococcus aureus that is responsible for anti-phagocytosis
Protein A and Polysaccharide A
Protein A and Polysaccharide A has the ability to bind to the _____ of the immunoglobulin, binding it in this manner can block phagocytosis and negate the protective effect of the immunoglobulin.
FC portion
Virulence Factor of Staphylococcus aureus that ocalizes abscess and acts as a virulence factor
Staphylocoagulase
Virulence Factor of Staphylococcus aureus that degrades DNA components of tissue and acts as a spreading factor
Hyaluronidase
This is the inflammation of hair follicle or oil gland; infected area is raised and red
Folliculitis
A relatively mild inflammation of hair follicle or oil gland in which the infected area is raised
Folliculitis
Extension of folliculitis; large, raised and superficial abscess
Furuncles (Boils)
Tagalog term for Furuncles (Boils):
“Pigsa”
These are cluster of boils and often present with fever and chills indicating that the infection is spread systemically or in the blood.
Carbuncles
A Staphylococcus aureus cutaneous infection that is larger than streptococcal nonbullous impetigo and is surrounded by a small zone of erythema
Bullous impetigo
Example of Deep Infections caused by Staphylococcus aureus:
Osteomyelitis
Periostitis
Tonsillitis
Pharyngitis
Sinusitis
Bronchopneumonia
Empyema
Septicemia
Meningitis
Endocarditis
Breast abscess
Renal abscess
Abscesses in other organs
An intoxication that results from the consumption of foods containing sufficient amounts of one or more preformed enterotoxin.
Food Poisoning
Symptoms of food poisoning appear rapidly, approximately _____ after ingestion of the food and resolve within _____
2-8 hours
24-48 hours
Common symptoms of food poisoning
Nausea, vomiting, abdominal pain and severe cramping
Rare symptoms of food poisoning
Diarrhea and headaches
A toxin with gated acute life-threatening illness caused by the enterotoxin F
Toxic Shock Syndrome
Most cases of Toxic Shock Syndrome occur in _____
Menstruating women who use tampons
How many percent of the cases of Toxic Shock Syndrome may be fatal?
2%-5%
Epidermolytic toxin produced by the staphylococcus aureus is responsible for the disease _____
Scalded Skin Syndrome
This infection causes peeling skin over large parts of the body and it looks like the skin has been scalded or burned by the hot liquid.
Scalded Skin Syndrome
Scalded Skin Syndrome is more common during _____ and _____
Summer
Fall
Scalded Skin Syndrome’s duration is brief, about _____
2-4 days
Bullous exfoliative dermatitis that occurs primarily in newborns and previously healthy young children
Staphylococcal Scalded Skin Syndrome
Staphylococcal Scalded Skin Syndrome’s severe form:
Ritter’s Disease
Staphylococcal Scalded Skin Syndrome’s milder form:
Pemphigus neonatorum and Bullous impetigo (localized form)
Staphylococcus aureus grow easily on routine laboratory culture media which is _____
Sheep Blood Agar (SBA)
Selective Medium for Staphylococcus aureus:
Mannitol Salt Agar (MSA)
Columbia Colistin–nalidixic Acid Agar (CNA)
Phenylethyl Alcohol Agar (PEA)
_____ in _____ makes this medium selective for Staphylococcus,
High NaCl concentration (7.5%)
Mannitol Salt Agar (MSA)
Incorporation of _____ and _____ distinguishes S. aureus from most CoNS.
Mannitol
Phenol red
Describe the Staphylococci spp. on SBA after 18-24 hours of incubation at 35° C to 37° C
Round, smooth, white, creamy colonies
Describe the Staphylococci spp. on BAP
Produce hemolytic zones around the colonies (beta-hemolytic)
Describe the Staphylococcus aureus on Nutrient Agar
- 1–3 mm in diameter and have a smooth glistening surface, an entire edge, a soft butyrous consistency and an opaque, pigmented appearance
- Appears golden yellow
An indicator medium and assists in the identification of S. aureus in mixed cultures
Phenolphthalein Phosphate Agar (PPA)
Phenolphthalein Phosphate Agar (PPA) become _____ when the culture plate is inverted over ammonia for a minute or so. This is an indicator medium to identify staphylococcus aureus in mixed code.
Bright pink
Phenolphthalein Phosphate Agar (PPA) become bright pink when the culture plate is inverted over _____ for a minute or so. This is an indicator medium to identify staphylococcus aureus in mixed code.
Ammonia
List down the Selective Salt Medias:
- 7–10% of sodium chloride may be added to Nutrient Agar (Salt Agar) or Milk Agar (Salt Milk Agar)
- Mannitol Salt Agar with 1% mannitol 3. 7.5% NaCl
- Nutrient Agar with Phenol Red
- Ludlam’s Medium containing lithium chloride and tellurite
- Salt Cooked Meat Broth (10% NaCl)
Identify the specie depending on its characteristics given:
Small- to medium-sized, nonhemolytic, gray-to-white colonies; some weakly hemolytic
Staphylococcus epidermidis
Identify the specie depending on its characteristics given:
Slightly larger colonies, with about 50% of the strains producing a yellow pigment
Staphylococcus saprophyticus
Identify the specie depending on its characteristics given:
Medium sized colonies, with moderate or weak hemolysis and variable pigment production
Staphylococcus haemolyticus
Identify the specie depending on its characteristics given:
Small to medium size colonies, often hemolytic
Staphylococcus lugdunensis
A test used to demonstrate the presence of catalase - an enzyme that catalyzes the release of oxygen from hydrogen peroxide (H2O2)
Catalase Test
Reagent used for the routine culture of Catalase Test:
3% H2O2
Reagent used for the detection of catalase in anaerobe:
15% hydrogen peroxide
Positive result of Catalase Test:
Bubble formation or effervescence
A biochemical test that is used to differentiate staphylococcus aureus from other staphylococci species like staphylococcus epidermidis and staphylococcus on the basis of the ability to produce the coagulase
Coagulase Test (Slide or Tube Method)
An enzyme-like protein and causes plasma to clot by converting fibrinogen to fibrin
Coagulase
Best single pathogenicity test for Staphylococcus aureus
Coagulase Test (Slide or Tube Method)
An enzyme that catalyzes the release of oxygen from hydrogen peroxide (H2O2)
Catalase
Specimen used in Slide Method
Plasma
This method detects bound coagulase or clumping factor
Slide Method
A screening test
Slide Method
Positive result of Slide Method
Agglutination
A Confirmatory Test
Tube Method
Specimen used in Tube Method
0.5 mL of Rabbit’s Plasma
Detects unbound coagulase or staphylocoagulase
Tube Method
Positive result for Tube Method
Coagulum/Clot
Medium used for Oxidation-Fermentation Reactions
O/F Glucose Medium or Hugh and Leifson’s Medium
Two methods under Oxidation-Fermentation (O/F) Reactions
Open Method
Closed Method
What is added on the closed tube in Oxidation-Fermentation (O/F) Reactions Test?
Mineral Oil or Paraffin Wax
If the closed tube or closed method yields a positive result, what does it indicates?
Yellow Color
Fermentative
If the open tube or open method yields a positive result, what does it indicates?
Yellow Color
Oxidative
If both the closed tube and open tube yields a positive result, what does it indicates?
Staphylococci
If the closed tube yields a negative result and the open tube produces a positive result, what does it indicates?
Micrococcaceae
What is the pH Indicator for Oxidation-Fermentation (O/F) Reactions?
Bromthymol Blue
Active chemical component of microdase disc used in Modified Oxidase Test:
Tetramethyl-para-phenylenediamine dihydrochloride
What is the positive result of Modified Oxidase Test?
Blue to purple to black complex
Micrococci
What is the negative result of Modified Oxidase Test?
No color change
Staphylococcus
What is the medium used in Mannitol Fermentation?
Mannitol Salt Agar
Positive result in Mannitol Fermentation indicates:
Yellow Color
Staphylococcus aureus
Negative result in Mannitol Fermentation indicates:
Pink Color
Coagulase-negative Staphylococci
Indicator used in Mannitol Fermentation Test:
Phenol Red
Medium used in DNAse test?
DNAse Medium
Indicator used in DNAse Test:
Methyl Green
Positive result of DNAse Test indicates:
Clearing of the area around the organism/Colorless zone around the organism
Staphylococcus aureus
Negative result of DNAse Test indicates:
No color change
Staphylococcus epidermidis
This is a test used to determine the ability of an organism to hydrolyze DNA and utilize it as a source of carbon and energy for growth.
DNAse Test
What is added to the DNAse medium if the medium doesn’t have a methyl green indicator?
1 N HCl or 1 normal hydrochloric acid
Positive test result on Gelatin Liquefaction/Hydrolysis Test:
Liquefaction of the medium after incubation and refrigiration
Staphylococcus aureus
Negative test result on Gelatin Liquefaction/Hydrolysis Test:
No changes on the medium (The medium is still semi-solid in form)
Staphylococcus epidermidis
This is a protein derived from the connective tissues of vertebrates that is collagen
Gelatin
Gelatin is a protein derived from the connective tissues of vertebrates that is _____
Collagen
_____ are proteases secreted extracellularly by some bacteria which hydrolyze or digest gelatine.
Gelatinases
Coagulase test result of Staphylococcus aureus:
Coagulase-positive
Coagulase test result of Staphylococcus epidermidis:
Coagulase-negative
Coagulase test result of Staphylococcus saprophyticus:
Coagulase-negative
Novobiocin test result of Staphylococcus aureus:
Susceptible
Novobiocin test result of Staphylococcus epidermidis:
Susceptible
Novobiocin test result of Staphylococcus saprophyticus:
Resistant
Polymixin test result of Staphylococcus aureus:
Resistant
Novobiocin test result of Staphylococcus epidermidis:
Susceptible
Novobiocin test result of Staphylococcus saprophyticus:
Susceptible
Sugar fermentation is of no diagnostic value except for _____, which is usually fermented anaerobically by S. aureus but not by other species
Mannitol
A Staphylococcus specie that is invariably present on normal man skin, infections are predominantly hospital acquired, and the most common cause of prosthetic valve endocarditis
Staphylococcus epidermidis
Predisposing factors of Staphylococcus epidermidis:
- Catheterization
- Medical Implantation
- Immunosuppressive theraphy
A Staphylococcus specie that causes UTIs in young women. This specie adheres more effectively to the epithelial cells lining the urogenital tract than other coagulase negative staphylococci. It is rarely found on other mucous membranes or skin surfaces.
Staphylococcus saphrophyticus
A Staphylococcus specie that cause both community-associated and hospital-acquired infections, can be more virulent and can clinically mimic S. aureus infections, and causes infective endocarditis, septicemia, meningitis, skin and soft tissue infections, UTIs, septic shock.
Staphylococcus lugdunensis
Staphylococcus has been known to contain what gene that encodes oxacillin resistance.
mecA Gene
Staphylococcus has been known to contain mecA that encodes _____
Oxacillin resistance
The most effective antibiotic if the strain is sensitive
Benzyl penicillin
Bacteria are sometimes able to produce penicillinase, an enzyme that degrades penicillin. This ability can spread throughout the bacterial population by a small ring of dna in a process called _____
Conjugation
This is an enzyme that degrades penicillin.
Penicillinase
This is the bacterial equivalent of sexual reproduction where individual organisms share new genetic information between them.
Conjugation
Antibiotics that are are used as penicillinase resistant penicillin.
Cloxacillin
Oxacillin
Flucloxacillin
These are the agents of choice in the treatment of systemic infection, but these agents are expensive and may be toxic.
Glycopeptides (Vancomycin or Teicoplanin)
For mild superficial lesions, topical applications of drugs such as _____, _____, _____ may be sufficient
Bacitracin
Chlorhexidine
Mupirocin
The treatment of carriers is by local application of antibiotics such as _____ and _____
Bacitracin
Chlorhexidine (Antispetics)
In resistant cases, _____ along with another oral antibiotic may be effective
Rifampicin
Refers to a group of gram-positive bacteria that are genetically distinct from other strains of Staphylococcus aureus
Methylene-resistant Staphylococcus aureus or MRSA
Methylene-resistant Staphylococcus aureus or MRSA is sometimes called _____
The Superbug
Any staphylococcus isolated is identified as being resistant to _____, this implies that it is also resistant to _____ and _____ and to antibiotics, including the _____.
Methicillin
Nafcillin
Oxacillin
Cephalosporins
_____ is generally used for detection of methicillin resistance.
Oxacillin
The use of an _____, such as the oxacillin resistance screening agar can be used as a screening test for MRSA in clinical samples
Oxacillin-salt agar plate
The use of an oxacillin-salt agar plat, such as the _____ can be used as a screening test for MRSA in clinical samples
Oxacillin resistance screening agar
Latest CLSI M100 document recommends _____ be used to detect oxacillin (methicillin) resistance
Cefoxitin
A _____ and _____ make the medium selective for staphylococci.
High salt concentration (5.5% NACl)
Polymyxin B
Gold standard for MRSA detection is the detection of the mecA gene by using _____ or _____.
Nucleic acid probes
Polymerase Chain Reaction (PCR) amplification
_____ is a better inducer of mecA mediated resistance
Cefoxitin
What was the year when the first vancomycin-intermediate Staphylococcus aureus (VISA) strains were recovered in Japan.
1996
It was year 1996 when the first _____ strains were recovered in Japan.
Vancomycin-intermediate Staphylococcus aureus (VISA)
It was year 1996 when the first vancomycin-intermediate Staphylococcus aureus (VISA) strains were recovered in _____.
Japan
This is a a macrolide which is frequently used in staphylococcal skin infections.
Clindamycin
What additonal test might be useful when the discrepant macrolide test results are obtained?
Modified double disk diffusion test (D-zone test)
A specie that catalase-positive, gram-positive, coagulase-negative and usually oxidase-positive. They may occasionally colonize the skin or mucous membrane of humans, but they are rarely associated with infections.
Micrococci
What are the two species under Micrococci:
Micrococcus luteus
Micrococcus lylae
These are specie that appears as gram-positive cocci in tetrads, rather than large clusters.
Micrococci
