Microbio ch. 18

Microbiology chapter 18 "gram-positive and gram-negative cocci of medical importance".

microbe described as gram-positive, a common inhabitant of the skin and mucous membranes, part of the normal human flora

staphylococci

normal inhabitant of the nose and skin. 1/3 people carry _____ in the nose

S. aureus

S. aureus is a _____ with its optimum temp being _____

mesophile, 37C

S. aureus oxygen requirements =

facultative anaerobe

S. aureus can withstand what environmental factors?

high salt, extreme pH, high temps

S. aureus produces many _____ _____

virulence factors

S. aureus produces _____ enzymes and _____ toxins

3, 5

“a protein or RNA molecule that acts as a biological catalyst, speeding up specific chemical reactions within cells without being consumed in the process” =

enzyme

“a poisonous substance produced by a living organism, like bacteria, that can cause disease or harm to other organisms” =

toxin

enzyme produced by S. aureus that coagulates blood and plasma, produced by 97% of human isolates

coagulase

enzyme produced by S. aureus that digests DNA

DNase

enzyme produced by S. aureus that inactivates penicillin

penicillinase

toxin produced by S. aureus that lyse red blood cells

hemolysins

the 4 types of hemolysis produced by S. aureus

alpha, beta, gamma, delta

toxin produced by S. aureus that lyses white blood cells, neutrophils and macrophages

leukocydin

toxin produced by S. aureus that induces gastrointestinal distress

enterotoxin

toxin produced by S. aureus that induces fever, vomiting, shock, and systemic organ damage

toxic shock syndrome toxin (TSST)

toxin produced by S. aureus that causes separation within the epidermis

exfoliatin toxin

type of plate that is non-selective and differential, used to distinguish clinically significant bacteria from throat and sputum cultures

blood agar (BAP)

type of hemolysis which results in greenish tint on BAP; incomplete hemolysis

alpha

type of hemolysis which results in a clear zone of complete hemolysis around isolated colonies

beta

type of hemolysis which results in no hemolysis or green tint on BAP

gamma

which bacteria are beta hemolytic?

s. aureus, strep. pyogenes

toxigenic disease that results in gastrointestinal distress, vomiting and diarrhea, caused by the toxin enterotoxin produced by s. aureus =

food poisoning

toxigenic disease that results in red flush, blisters, and desquamation of the epidermis, caused by the toxin exfoliatin toxin produced by s. aureus =

staphylococcal scalded skin syndrome

toxigenic disease that results in systemic toxemia that leads to massive immune system response to shock and organ failure, cause by TSS toxin produced by s. aureus =

toxic shock syndrome (TSS)

an infection acquired in a hospital/medical setting =

nosocomial

nosocomial MRSA can lead to =

endocarditis, necrotizing pneumonia, surgical site infections

what factors influence antibiotic resistance?

poor patient compliance, overprescribing, improper disposal

type of molecular antibiotic resistance in which the gene is transferred from one bacterium to another =

conjugation

type of molecular antibiotic resistance in which the gene is absorbed from a bacteria’s environment =

transformation

_____ bacteria can absorb things from their environment

competent

bacteria that is typically commensal, opportunistic pathogen, comprises 60-90% of staph. in the body, most common cause of medical device infections, costs related to catheter blood infections are estimated to be 2B in US alone =

staph. epidermis

bacteria that is the 2nd leading cause of uncomplicated UTI in women, normal inhabitant of GI tract, main virulence factor is lipotechoic acid =

staph. saprophyticus

which bacteria is the number 1 leading cause for uncomplicated UTIs in women?

escherichia coli

group of streptococci that is most common and typically non-invasive. inhabits throat, nasopharynx, occasionally skin

group a

non invasive forms of group A streptococci cause =

strep throat, impetigo

strep throat is also known as =

streptococcus pyogenes

a highly contagious skin condition, often in children, sores surround mouth and nose =

impetigo

serious and invasive forms of group A streptococci cause =

necrotizing fasciitis, streptococcal toxic shock syndrome

a substance that induces the production of antibodies that is recognized as non-self by the immune system =

antigen

proteins secreted by our immune cells that bind antigens and mark them as targets for phagocytes =

antibody

group A streptococcus pyogenes produces _____ surface antigens, and _____ extracellular toxins

4, 3

the surface antigens of group A streptococcus include =

c-carbohydrates, fimbriae, m-protein, hyaluronic acid capsule

group A streptococcus surface antigen that protects against lysozyme =

c-carbohydrate

group A streptococcus surface antigen that functions in adherence =

fimbriae

group A streptococcus surface antigen that contributes to resistance to phagocytosis =

m-protein

group A streptococcus surface antigen that provokes no immune response =

hyaluronic acid capsule

extracellular toxins produced by streptococcus pyogenes include =

streptolysins, erythrogenic toxin (pyrogenic), superantigens

extracellular toxin produced by streptococcus pyogenes that are hemolysins; cause cell and tissue injury =

streptolysins

extracellular toxin produced by streptococcus pyogenes that induces fever and typical red rash =

erythrogenic toxin (pyrogenic)

extracellular toxin produced by streptococcus pyogenes that is a strong monocyte and lymphocyte stimulant; cause the release of tissue necrotic factor =

superantigen

long term sequelae of group A infections include =

rheumatic fever, acute glomerulonephritis

disease that follows overt or subclinical pharyngitis in children, extensive valve damage possible, arthritis, chorea, fever =

rheumatic fever

disease characterized by nephritis, increased blood pressure, occasionally heart failure, can become chronic leading to kidney failure =

acute glomerulonephritis

group of streptococci that typically reside in vagina, pharynx, and large intestine. illness is predominantly in newborns and non-pregnant adults over 60y old =

group b

which illnesses can be caused in newborns within their 1st week of life by group B streptococci?

neonatal pneumonia, sepsis, meningitis

group of streptococci that typically reside in large intestine, non-pathogenic but can cause opportunistic infections, urinary tract, wounds and skin in debilitated people. vancomycin-resistant enterococcus (VRE) =

group d

group D streptococci can cause infections in which areas of the body?

urinary tract, wounds, skin of debilitated people

bacteria that causes 60-70% of all bacterial pneumonias, 5-50% people carry in nasopharynx, most common cause of community acquired pneumonia, pathogenic strains form capsules (virulence factor) =

streptococcus pneumoniae, pneumococcus

gram-negative bacteria that causes gonorrhea, grows in reproductive tract and urethral canal =

neisseria gonorrhoeae, gonococcus

what 2 virulence factors does neisseria gonorrhoeae possess?

fimbriae, iga protease

which neisseria gonorrhoeae virulence factor cleaves secretory IgA?

iga protease

bacteria transmitted through exchange of respiratory and throat secretions, prevalent cause of meningitis, high risk ppl include those in close quarters, children and young adults 10-20yrs =

neisseria meningitidis, meningococcus

disease that has a very rapid onset, neurological symptoms, endotoxin causes hemorrhage, shock, possibly necrosis of tissues; can be fatal =

meningitis

what 4 virulence factors does meningococcus possess?

capsule, fimbriae, iga protease, endotoxin

the groups of streptococci include =

a, b, c/g, d

a strain of the bacterium Staphylococcus aureus that has become resistant to the antibacterial action of the antibiotic methicillin, a form of penicillin; 2/10 people carry MRSA in their nares; multi-drug resistant

methicillin resistant staphylococcus aureus (MRSA)

An infection caused by Vancomycin-resistant Staphylococcus aureus that is difficult to treat because it exhibits resistance to nearly all available antibiotics; multidrug resistant

Vancomycin Resistant S. aureus (VRSA)

Main Virulence Factor of Staphylococcus saprophyticus =

lipotechoic acid for adherence

gram positive medically relevant cocci =

Streptococcus, Staphylococcus

gram negative medically relevant cocci =

Neisseria

what is the correct order of events for antibiotic resistance?

bacterial mutation, selection (antibiotic exposure), susceptible bacteria die, outgrowth of resistant strain