OCTC-Micro-Chapter 19

Pathogenic Gram-Positive Cocci and Bacilli
Stain purple when gram-stained
Staphylococcus is a _____ member of every human’s microbiota.
Staphylococcus is located:
In nasopharynx
On skin
Colonizes the infant w/in hours
Staphylococcus found in hospitals in
Nurseries and surgical wards.
Staphylococci live and reproduce on
almost every square inch of human skin
Staphpylococcus can be ______ pathogens causing anywhere from minor to life threatening diseases
Staphylococcus genus name comes from Greek term staphle meaning ______
“bunches of grapes”
Coccus (pl.cocci) =
spherical–shaped bacterial cell
staph =
staff or group (Cluster like grapes)
Staphylococcus colonies appear
cream colored, white to light gold, and “buttery-looking”
Staphylococcus is Gram _____
positive cocci, nonmotile, facultative anaerobes
Staphylococcus grows best when _____ present, but can continue to grow under ____ conditions.
O2, anaerobic
Staphylococcus is _____-tolerant
Staphylococcus tolerates the ____ present on human skin
Staphylococcus is tolerant of desiccation (capsule). What does this mean?
allows survival on environmental surfaces such as fomites
Object inadvertently used to transfer pathogen to new host: needle or coin
Staphylococci are catalase positive or negative?
Catalase Converts H202, (hydrogen peroxide) Into_____ and ____?
H20 and 02
Staphylococci can disarm neutrophil’s and macrophage’s H2O2 with ______?
_______ is secreted by neutrophils and macrophages to kill bacteria
Hydrogen peroxide
To test for catalase:
Inoculating loop is rubbed across a colony of Staphylococcus and mixed with H202 on a slide.
If bubbles appear, the enzyme catalase must be present.
So Staphylococcus is catalyst positive
Staphylococcal infections range from the
trivial to the rapidly fatal
Are Staphylococcal infections easy to treat?
No, They can be difficult to treat
Why are Staphylococcal infections difficult to treat?
Because staphylococci can acquire antibiotic resistance
“Staph” infections result when staphylococci
breach the body’s physical barriers.
Entry of only a few hundred bacteria (ID) can result in
Staphylococci are ______ in nature with about a _____ species part of our human flora
ubiquitous, dozen
How many species are commonly associated with staphylococcal diseases in humans?
What are the 2 species commonly associated with staphylococcal diseases in humans?
1.Staphylococcus aureus is one of the most common causes of infections
2.Less virulent,opportunist Staphylococcus epidermis may cause prosthetic implant infections
Staphylococcus aureus is one of the most common causes of
Less virulent, opportunist Staphylococcus epidermis may cause
prosthetic implant infections
Staphylococcus epidermidis is the______ of human skin
Normal microbiota
Staphylococcus epidermidis is the normal microbiota of human skin that can cause ?
opportunistic infections to immunocompromised patients or when introduced into parts of body
Staphylococcus aureus is located on
skin, nares, mucous membranes (pharynx and vagina)
What pigment is Staphylococcus aureus on sheep blood agar?
Gold pigment
Pathogenicity of Staphylococus (3 things)
1.Cell wall structures that prevent phagocytosis
2. Enzymes
3. Production of toxins
Cell wall structures that prevent phagocytosis (3 things)
a. Protein A
b. Bound coagulase
c. Capsule/slime layer
2. Enzymes (5 things)
a. Coagulase
b. Staphylokinase
c. Hyaluronidase
d. Lipase
e. B-lactamses
3. Toxins (4 things)
a. Cytolytic toxins
b. Exfoliative toxins
c. Toxic-shock-syndrome (TSS) toxin
d. Enterotoxins
Staphylococcus aureus has Protein A which causes_____to bind upside-down _____ antigen. This _____ opponization and ________.
antibody stems,S. aureus
Inhibits, phagocytosis
Staphylococcus aureus has ________ that converts fibrinogen into ______ that form clots around pathogen.
enzyme coagulase, fibrin
Fibrin clots ______ Staphylococcus aureus from phagocytic cells
Staphylococcus aureus forms slime layer/capsule that prevents:
Phagocytosis and Dessiccation
Slime layer facilitates attachment of
Staphylococcus to artificial surfaces such as (5 things)
catheters, shunts, artificial heart valves and joints
Coagulase triggers fibrin clotting, which hides the _______
Staphylococcus aureus
Dissolves fibrin threads in clots, allowing S.aureus to free itself from clots and spread to new location
Breaks down hyaluronic acid, enabling S. aureus spread deeper between cells
Lipases =
digest lipids allowing Staphylococcus aureus to grow on surface of skin and sebaceous glands
B-lactamase =
penicillinase now in 90% of S. aureus strains and thus resistant to penicillin and cephalosporins
Cytolytic toxins Disrupts the ______ ______ ______of a variety of cells such as
mammalian cytoplasmic membrane
Heart, skeletal muscle, renal cells, platelets
Hemolysins damage
Leukocidin lyses
Leukocytes, Macrophages, and neutrophils
Leukocidin provides S. aureus ______ from _____.
protection from phagocytosis
Exfoliative toxins = ET causes
Exfoliative toxin dissolves
The patient’s epidermal layer of skin to slough off
Toxic-shock-syndrome toxin symptoms
High fever, rash, peeling of skin, vasodilation, drop in BP
Staphylococcus aureus produces enterotoxin proteins which in turn stimulate which 4 things?
Intestinal muscle contractions
Intense vomiting
Associated with staphylococcal food poisoning
Staphylococcus aureus Enterotoxins are ____ stable
Heat does not denature_____ protein
cover dish dinner; take home leftovers; reheat = zap in microwave. This process Does not _______the Enterotoxin
Staphylococcal Diseases categorized as which 3 things?
1. Noninvasive Disease
2. Cutaneous Disease
3. Systemic Disease
1. Noninvasive Disease
Food poisoning
Ingestion of Staphylococcus aureus contaminated food
Ingestion of Staphylococcus aureus contaminated food Bacteria grow on food and secretes
Enterotoxin that is heat stable
Common cause of food poisoning?
Staphylococcus aureus
Food poisoning is caused by ______ rather than by ______ of the bacteria
enterotoxin, invasion
Food must remain at ________for several hours for bacteria to grow, reproduce, and produce toxin
room temperature
Enterotoxin causes ____, ____, ____ for how long?
nausea, vomiting, diarrhea for 24 hours
Reheating may kill ______ bacteria but does not inactivate _______.
S. aureus, enterotoxin
2. Cutaneous Disease
Various skin conditions: name 6
Scalded skin syndrome
Staphylococcus aureus causes localized _______(pus filled lesions)lesions
Pyogenic =
pus filled lesions
Scalded skin syndrome =
Exfoliative toxin causes: name 4 things
Reddening of skin
Large blisters
Epidermis peels off in two days
Subject to secondary bacterial infection
Scalded skin syndrome = Exfoliative toxin Usually affects ______ of severed umbilicus & Older children with ______.
neonates, skin infections
Staphylococcus aureus causes 80% of
impetigo is what and occurs on who?
Small, flattened, red patches on face, limbs of children whose immune system is not fully developed
impetigo mostly occurs on _____ as pus filled vesicles that crust over and become honey colored, wet, flaky. The pus is filled with ____ and ____
face, S. aureus and WBC
Folliculitis =
Infection of hair follicle
Folliculitis Becomes red, swollen, and pus filled. When it occurs at base of eye in eyelash follicle it is called a
Furuncle = boil
Penetrates into the ______?
Large, painful, raised nodular extension of folliculitis to surrounding tissue.
Penetrates into the subcutaneous layer
Carbuncle =
several furuncles coalesce
Larger, deeper, more painful
May have to be surgically drained
Can be the size of baseball
Carbuncle May cause____ and _____ as S. aureus spreads into underlying tissues
may need ______.
fever, chills, antibiotics
S. aureus can cause a variety of potentially fatal _____ _____ When introduced to deeper tissues of the body such as ___, ____, ____, and ____.
systemic infections
Blood, heart, lungs, and bones
3. Systemic Disease 6 things
Staphylococcus aureus produce _____ toxin
Staphylococcus aureus can grow in a _____ or _____ vagina and produce the toxin and cause______.
Toxic shock syndrome
can TSS occur in both males and females?
Toxic Shock Syndrome Toxin causes:
Vomiting and Diarrhea
Red rash
Loss of sheets of skin
Low BP, shock
Multi-organ failure due to shock
TSS fatal in ____% cases. Why?
5%, When BP drops so low O2 cannot be carried to vital organs and causes shock, death
Staphylococcus aureus in blood is ______ and Accounts for half of all ______ infections
Bacteremia , noscomial
Staphylococcus aureus Bacteremia Causes:
Vaginal infections
Infected surgical wounds
Hospitalized patients with chronic disease that contract S. aureus bacteremia have a
high mortality rate
Staphylococcus aureus = Endocarditis
Attacks lining of heart and valves
Endocarditis is one of the consequences of _______.
staphylococcal bacteremia
Staphylococcus aureus = Endocarditis
Symptoms are _____ and ______.
nonspecific, flulike
Staphylococcus aureus = Endocarditis
Blood pumped from heart ______ which in turn makes the ____ drop.
50% patients do not
drops, BP, survive
Staphylococcus aureus in blood invades _____ causing______.
lungs, pneumonia
Mortality rate for staphylococcal pneumonia is _____%.
Staphylococcal pneumonia known to occur as secondary infection to
Staphylococcal pneumonia Particularly occurs in _____ and_______ patients
infants,cystic fibrosis
In 10% of patients with Staphylococcal pneumonia… The fluid filling the alveoli is _____, this condition is called ______.
pus, empyema
When Staphpylococcus aureusInvades a bone, it causes
Staphylococcal osteomyelitis
Staphylococcal osteomyelitis Signs and symptoms are: Inflammation of
Bone marrow, diaphysis and periosteum
Fever, Chills, Swelling and pain
(Brake hip and get stahpylococcus aureus infection in bone)
Diagnosis of Staphylococcus Infections
Detection of Gram-positive bacteria
Isolated from pus, blood, or other fluids
Treatment: ______ is the drug of choice to treat staphylococcal infections.
Treatment:Since (1962) 1987 have:
methicillin-resistant Staphylococcus aureus
Treatment: Since 2002 have:
vancomycin resistant S. aureus
Prevention = some humans are carriers
Hand antisepsis
Proper cleansing of wounds and surgical openings
Aseptic use of catheters or indwelling needles
Appropriate use of antiseptics
The Genus Streptococcus Is a diverse group of
Gram positive cocci
Streptococcus can be arranged in ____ or ______
Pairs or chains
Streptococcus are arranged in pairs called
Streptococcus are Arranged in chains like a strip of button
candy called
Streptococcus is Catalase _____
Most Streptococcus are _______ ________.
facultative anaerobes
Serological classification of Streptococcus is useful in _______.
The Lancefield classification Developed by Rebecca Lancefield in 1938 was
Based on ______ ______.
serological classification
The Lancefield classification puts various strains of Streptococcus into _____ different groups.
Lancefield groups go from _____ to ____.
A – S
Lancefield groups A and B are ______ and ______.
GAS and GBS Include the significant streptococcal pathogens of _____.
There are _____ species of Streptococci
only a few (5) are ______ _______.
Thirty, human pathogens
Group A Streptococcus =
Streptococcus pyogenes
What do Group A (GAS) Streptococcus pyogenes look like?
Looks like chain of purple pearls on slide
Group A Streptococcus: GAS
On blood agar plate, Streptococcus pyogenes forms ______ colonies surrounded by _____ of beta-hemolysis on blood agar plates.
white, zone
Streptococcus pyogenes lyse _____ leaving a ____ zone around ____ colony.
RBC, clear, white
What is the main representative of group A Streptococcus (GAS)?
Streptococcus pyogenes
What is the most serious streptococcal pathogen?
Streptococcus pyogenes
Streptococcus pyogenes has a number of
Structures, Enzymes and Toxins that enable it to survive as a ______.
Pathogenic strains of Streptococcus pyogenes form _____
What are the structural components and enzymes of Streptococcus pyogenes? 5 things?
1.Protein M (protein A in S. aureus)
2.Hyaluronic acid capsule
3.Streptokinase Enzymes
4.Hyaluronidase = spreading factor
Protein M ________ complement. Thereby interfering with opsonization, phagocytosis, and lysis of bacteria.
Hyaluronic acid capsule acts to ______ the bacteria
camouflage(WBC cannot recognize)
Streptokinase Enzymes ______ blood clots and _______ spread of Streptococcus pyogenes into ______ and _____tissue
dissolves, facilitates, damaged and infected
Hyaluronidase called the ______ ______, dissolves hyaluronic acid and facilitates spread of Streptococcus pyogenes into deeper tissue
spreading factor
What are Streptococcus pyogenes major Extracellular Toxins? 3 things
Pyrogenic toxins/ Erythrogenic toxins
Streptolysins toxins
Streptococcus pyogenes :Pyrogenic toxins Stimulate______ and ______ cells to release cytokines/pyrogenes
macrophages and helper T cells
Streptococcus pyogenes :Pyrogenic toxins Stimulate ______ , causes ____ , and _____ toxic shock
fever,rash and streptococcal
Because Pyrogenic toxins cause blood capillaries near surface of skin to dilate producing a red rash known as ____ _____, Some scientist call the toxins _________ toxins
(scarlet fever), Erythrogenic
Streptolysins toxins Cause _____ of sheep blood agar. Clear zone around colony
Streptolysins toxins Lyses _____, _____ and _______Which interfere with O2 carrying capacity, Immunity, Blood clotting.
RBCs, WBCs and Platelets.
Streptolysins toxins also lyse other tissue cells such as
Liver cells
Cardiac muscle cells
Kidney cells
Humans are only significant reservoir of ___ to ____ % of population are carriers of virulent strains of Streptococcus pyogenes
Streptococcus pyogenes
Typically causes disease when:
Competing normal flora is depleted
Immunity is impaired
When large inoculum enables it to get a foot hold (infectious dose) before antibodies form against it
Streptococcus pyogenes
Causes following diseases: KNOW these 7
Strep throat
Streptococcal toxic shock syndrome
Necrotizing fasciitis
Scarlet fever
Rheumatic fever
Post streptococcal glomerulonephritis
What is the Streptococcus pyogenes strain for Sore throat, strep throat, or tonsillitis ?
Streptococcal pharyngitis
Bacteriological or serological testare needed for a sure diagnosis of ______ _____
Streptococcal pharyngitis
What is Streptococcal pharyngitis treated with?
What is a Sequela?
a condition following and resulting from a disease
_____ is a morbid complication that follows a disease
Some diseases leave sequela In the form of long-term or permanent
Damage to tissues or organs
Examples of Sequelas:
Meningitis can result in _____
Examples of Sequelas:
Strep throat can result in _____ _____
scarlet fever
Examples of Sequelas:
Strep throat can result in _____ ______ disease
rheumatic heart
What is Pyoderma?
streptococcal impetigo
streptococcal impetigo is a localized _____ ______.
skin disease
streptococcal impetigo Begins as small _____producing lesions that itch, break open and form contagious yellow crust on skin
Pyoderma = ____ producing lesion on skin of face, arms, and legs
Erisipelas =Slightly more invasive form of ______ infection spreads to _____ and _____ tissues.
skin, dermis and subcutaneous
Streptococcus pyogenes: Erisipelas
is called Erysipelas when this infection involved ____ _____.
Triggers pain and inflammation
lymph nodes
Hogs can get ______ and infected hogs can infect______
Erysipelas, humans
Streptococcus pyogenes can also cause
Streptococcal _____ _____ ______.
toxic shock syndrome
Patients are bacteremic with severe multi-system infections and failure if they contract ______?
Necrotizing fasciitis =
Flesh eating strep
Necrotizing fasciitis Life threatening with mortality rate of ____% if left untreated
Flesh eating Streptococcus pyogenes
follows the path of _____ between subcutaneous tissue and muscle and CT surrounding the muscles
Flesh eating Strep Streptococcus pyogenes first symptoms
Swelling, heat, redness
Skin changes from red to purple to blue to large blisters
Flesh eating Streptococcus pyogenes
Skin dies and muscle becomes infected. Need rapid therapy of which drug?
penicillin G
What are used to remove the dead tissue sometimes?
Rheumatic Fever is a sequila. which disease does it follow? What does it result in?
strep throat
Results in damage of heart valves and heart muscle.
Rheumatic Fever is an _______ response to Streptococcus pyogenes.
Rheumatic Fever is ______ mediated. Antigens in heart are similar to
Antigens on Streptococcus pyogenes, and our_____attach to heart muscle, attack it and causes ____which can damage the heart valves.
antibody, antibodies, myocarditis
Acute Glomerulonephritis = AGN
Antibody-antigen complexes of ____ ____. Accumulate in ______.
Obstructs blood flow through _____.
Streptococcus pyogenes, glomeruli, kidneys
Acute Glomerulonephritis = AGN
Sequela of ______ ______.
Streptococcus pyogenes
Acute Glomerulonephritis = AGN
Leads to ______ and ______ urine output
Face may be puffy, urine is _____ colored
hypertension, low, tea
Acute Glomerulonephritis = AGN may cause _____kidney damage in adults.
Diagnosis of Streptococcus pyogenes
Observation of Gram-positive bacteria in short chains or pairs
Prevention of Streptococcus pyogenes:
Antibodies against M protein provide long-term protection against future infection of S. pyogenes ONLY it it is _____?
the same strain of Streptococcus
(can get strep throat many times from different strains)
GBS = Group B Streptococcus:
Streptococcus agalactiae
Not until Lancefield classification scheme was Streptococcus agalactiae(GBS)Recognized in _____
Streptococcus agalactiae
Newborns with no antibodies are at risk of infection if born to previously uninfected mothers with no antibodies. Why is this?
No antibodies for S. agalactiae were passed to fetus during late gestation
Streptococcus agalactiae normally colonizes which 3 things?
GI, Genitals, and urinary tract
Newborns can pick up _____ ______ in birth canal during birth
S. agalactiae
CDC recommends prophylactic administration of ______ at birth to neonates whose mother’s urinary/genital tract is colonized with S. agalactiae
Streptococcus _____Causes serious infections in newborns and immunocompromised people
think Baby for GBS-
Streptococcus _____ causes Causes of neonatal pneumonia, sepsis, and meningitis
Streptococcus agalactiae resides in human ____, ____, _____, and ______.
pharynx, vagina, urinary tract, and large intestine.
Viridans Streptococci
(verdant, viridis L. = green)
Many produce green pigment when grown on blood agar
Viridans Streptococci is the normal flora in ____, ____, _____, ____ and _____.
Oral cavity, pharynx, GI tract, Urinary and genital tracts
Ex. Of Viridans Streptococci
Streptococcus mutans causes _____ _____.
dental caries.
During a dental procedures (routine cleaning teeth) there may be showers of Streptococcus mutans into the ______
Streptococcus mutans may cause
People with heart conditions or heart murmurs are given _____ antibiotics before visit to dentist.
Streptococcus pneumoniae Gram ____ cocci
Streptococcus pneumoniae most commonly forms pairs called ______, formally called _______ _______
Diplococcus pneumoniae
There are ____ strains of Streptococcus pneumoniae discovered by ______. There are vaccines against ____ strains.
92,Louis Pasteur, 23
_____ % of all people carry Streptococcus pneumoniae as normal flora in mouth and pharynx without causing harm BUT if it moves to lungs causes
75%, pneumonia
Steptococcus pneumoniae most common cause of which 3 things?
Pneumonococcal pneumonia
Otitis media
Streptococcus pneumoniae important cause of _______ ________ (since we now have a vaccine for Hemophilus influenzae, HiB vaccine), _____ and _____.
Pneumococcal meningitis
Categories: Microbiology