lab exam 2 review Flashcards
A patient has Hep B antibody titre of 640, what does this mean?
Patient has developed antibodies to Hep B virus through immunization or natural exposure to the virus. The patient has seroconverted (produced antibodies)
Define Antigen
chemical substance, usually protein that elicits an immune response. Antigens are usually proteins, but substrances such as glycoprotine, lipoproteins or large complexes carbohydrates may be antigens
Define Antigenic determinant (epitope)
the portion of the antigen that stimulates and immune response
Define Antibody
A defensive protein produced in response to antigenic (epitope) stimulation. It is capable of binding to the epitope of the antigen it was produced against. Once the antibody and antigen bind to each other, other defensive processes are activated.
What other defensive processes are activated after the antigenic (epitope) and antibody bind?
Antibody binds to macrophage leading to phagocytosis of antigen
Antibody coats antigen attached to a virus neutralizing it, also blocks entry into areas
Complement can be activated by IgG and IgM; destruction of antigen
What is the Gram reaction of the following species? Spore former? Staphylococcus aureus? Staphylococcus epidermidis? Streptococcus agalactiae? Streptococcus pyogenes? Streptococcus pneumoniae?
Staphylococcus aureus - G+, staphylococci
Staphylococcus epidermidis - G+, staphylococci
Streptococcus agalactiae - G+, streptococci
Streptococcus pyogenes - G+, streptococci
Streptococcus pneumoniae - G+, diplococci
What is the Gram reaction of the following species? Spore former? Escherichia coli? Pseudomonas sp.? Klebsiella pneumoniae? Proteus sp.? Salmonella sp.? Shigella sp.?
Escherichia coli - G-, bacilli Pseudomonas sp. - G-, bacilli Klebsiella pneumoniae -G-, bacilli Proteus sp. - G-, bacilli Salmonella sp. - G-, bacilli Shigella sp. - G-, bacili
What is the Gram reaction of the following species? Spore former?
Bacillus sp.?
Clostridium sp.?
Bacillus sp. - G+ bacilli, spore former
Clostrium sp. - G+ bacilli, spore former
What is the hemolytic pattern of the following
Streptococcus pneumoniae?
Streptococcus pyogenes?
Staphylococcus epidermidis?
Streptococcus pneumoniae - Alpha hemolysin
Streptococcus pyogenes - Beta hemolysin
Staphylococcus epidermidis - Gamma hemolysin
Compare and contrast agglutination and precipitation
Similarities:
both involve antigens and antibodies
both involve epitopes binding to antibodies
both identify an unknown if either the antigen or antibody is known
Difference:
agglutination involves particulate antigens; precipitation involves soluble antigens
agglutination involves physical mixing to bring antigen and antibody closer together; precipitation involves diffusion
agglutination results in a large particulate mass forming (clumps) where cross linking occurs between the antigen and antibodies; precipitation involves diffusion until a zone of equivalence is reached and a lattice forms
Name a chemical that is bactericidal against Bacillus sp.
Cidex
Describe Gram positive bacterial cell wall
Peptidoglycan 60-90% -Teichoic acid -Lipoteichoic acid Cell membrane -Phospholipid
Describe Gram negative bacterial cell wall
Outer membrane -LPS -Porins Periplasmic space -Lipoproteins -Peptidoglycan 10% Cell membrane
Tuberculosis, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Mycobacterium tuberculosis
Acid fast stain
Acid fast positive due to high mycolic acid content in cell wall; agent of tuberculosis
Strep throat, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Streptococcus pyogenes (GAS)
Gram stain: G+ streptococci
Agent of strep throat; bacitracin sensitive; quick antigen test used; sequelae; Scarlet fever, glomerulonephrities, rheumatic fever.
Treatment: penicillin, cephalosporin, erythromycin
Pneumococcal pneumonia, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Streptococcus pneumoniae
Gram stain: G+ diplococci
Cause of pneumonococcal pneumonia; resistant strains
Treatment: vancomycin
Prevention: vaccine and decrease high risk behaviors
Scarlet fever, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Streptococcus pyogenes
Caused by GAS such as strep throat or a skin infection
Rash caused from erythrogenic exotoxin released from the bacgterium➝ increased capillary permeability ➝ blood leaks from vessels. The tongue may have a strawberry appearance; skin areas with rash may peel; usually full recovery with antibiotics
Diptheria, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Corynebacerium diptheriae
Gram stain: G+ bacilli with pleomorphism (shape shapes)
Acute URT disease, highly infectious
Haemophilus influenzae meningitis, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Haemophilus influenzae, type B
Gram stain: G- bacilli
Causes meningitis in infants, your children and the immunocompromised
Gonorrhea, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Neisseria gonorrheae
Gram stain: G- diplococci, look for intercellular GNDC in neutrophils.
Syphilis, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Treponema pallidum
Don’t gram stain. Use Dark Field microscope to view spirochete; serology testing and fluorescent microscopy.
Person to person contact.
Primary, Secondary, Tertiary and congenital
Cystitis, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Infection of the bladder caused by Escherichia coli
Gram stain: G- bacilli
Chlamydia, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Chlamydia trachomatis
Infectious mononucleosis (IM), - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Epstein Barr virus
Tetanus, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Clostridium tetani
Gram stain: G+ bacilli, spore former, strict anaerobe
Psittacosis, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Chlamydia psittaci
Serological test
Small bacterium; obligate intracellular parasite; treat with tetracycline; organism is obtained from inhaling contaminated dust/bird feces
Primary atypical pneumonia, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Mycoplasma pneumoniae
Cannot be gram stained, lack cell wall.
Human to human contact, inhaling contaminated respiratory droplets; causes bacterial pneumonia that present as a viral pneumonia; use antigen and antibody test to ID
Klebsiella pneumonia, - provide the following:
Etiologic agent?
Staining technique used to ID microbe?
Other pertinent info?
Klebsiella pneumoniae
Gram stain: G- bacilli
URT flora for some; capsule; caused by impaired pulmonary funcation; increased risk - alcohol intake, malnutrition, nosocomial infection.
Treatment: cephalosporin
Define Monoclonal antibody
an antibody produced by a single clone of cells or cell line and consisting of identical antibody molecules.
Define Antisera
Antiserum is human or nonhuman blood serum containing polyclonal antibodies and is used to pass on passive immunity to many diseases.
Define Experimental variable
Various disinfectants
Define MIC
Minimum Inhibitory Concentration
Define Control variable
same organisms tested against varying chemicals and timeline was the same
Define Antiseptic
Chemicals applied to body surfaces to destroy or inhibit vegetative microbes.
ex. alcohols (60-90%), hydrogen peroxide, betadine, saline (>0.9%). Chemical agent
Define Disinfectant
Destruction/removal of vegetative microbes (no bacterial endospores). Used on inanimate objects due to intensity. ex. lysol, cidex, bleach, heat, UV, boiling water. Physical agent.
Define Penicillinase (beta-lactamase)
An enzyme produced by penicillin resistant strains of bacteria to inactivate penicillin into a harmless chemical (penicilloid)
List 6 indigenous microbiota of the URT
Streptococcus sp. Staphylococcus sp. Corynebacterium sp. Neiserria sp. Candida albicans Anaerobes
List 5 classes of antibodies
IgA, IgM, IgG, IgD, IgE
Hektoen-Enteric (HE) agar
all info
All organisms growing on them are usually GNB
Facultative anaerobes and enteric organisms
GP bacteria an fastidious GN bacteria are inhibited due to the increased amount of bile salts and dyes
Differentiates between lactose and non lactose fermenters using pH dyes that change color in an acidic environment.
When ferments lactose, acids are produced lowering the pH and changing the pH indicator dye a different color
Detect black colonies (H2S)
MacConkey (MAC) agar
all info
All organisms growing on them are usually GNB
Facultative anaerobes and enteric organisms
GP bacteria an fastidious GN bacteria are inhibited due to the increased amount of bile salts and dyes
Differentiates between lactose and non lactose fermenters using pH dyes that change color in an acidic environment.
When ferments lactose, acids are produced lowering the pH and changing the pH indicator dye a different color
Mueller Hinton agar
all info
Grows most non fastidious bacteria
Used from susceptibility testing in the Kirby Bauer test
Agar plates are poured 4mm in depth
Neutral pH
Thayer Martin agar
all info
Chocolate agar enriched medium; sheep blood cells that have been lysed and oxidized, plus antibiotics which inhibit all organisms EXCEPT Neisseria species (fastidious organism)
Explain how cationic detergents work
Cationic detergents have positively charged ion which is attached to larger hydrophobic ion used to disinfect. Does not kill endospores but will kill some viruses.
Explain how soap works (chemically and physically)
Soaps- a cleaning agent that enhances the physical removal of microbes and debris but typically does not kill the microbes. Methods may involve disinfection and antisepsis.
Soaps are made from fats/oils. Forms oily surface which break down microorganisms ➝ slides off surface
Which one is more resistant to numerous antimicrobial agents?
Staphylococcus aureus
OR
Psuedomonas sp.
Psuedomonas sp.
What role does secretory IgA play in protecting the URT?
Secretory IgA is found in body secretions near the surface. It binds to microorganisms and prevents them from attaching and invading mucous membranes.
Ex. Vibrio cholerale, Streptococcus mutans and Neisseria gonorrhoaea will not bind to host cells in the presence of secretory IgA
What are coliforms?
A collective term that includes normal enteric bacteria they are gram negative and lactose fermenting
Why should infants and toddlers be kept away from iguanas?
Salmonella……
What is the usual mode of transmission for gonococcal ophthalmia in newborns? What is the etiologic agent? What is the recommended therapy?
Vaginal delivery where the newborn pick up the pathogen from maternal vaginal flora
Nesseria gonorrheae
Erythromycin eye drops
What syphilitic stage presents with a rash on the palms and soles?
Secondary syphilis
