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Side A ------ Side B
Describe the appearance of staphylococci on a smear? (gram +/- and what arrangement) ------ gpc, pr, cl
Describe the appearance of micrococci on a smear? (gram +/- and what arrangement, size) ------ gpc, TETRADS!!! (this distinguishes micrococci from staphylococci), they are also larger than staph.
Describe the appearance of staphylococci on BAP (poss colors, poss hemolyses) ------ cream, golden, white, BH or NH, op
Describe the appearance of micrococci on BAP (color) ------ stable pigment, can be carotenoid (yellow or red) esp at lower temps
What kind of atmosphere do staph. require? (ie. what are they in terms of oxygen/carbon tolerance/use) ------ Facultative ANAEROBE
What kind of atmosphere do micrococci require? (ie. what are they in terms of oxygen/carbon tolerance/use) ------ AEROBES
What are the results for staph when a lysostaphin and modified oxidase test are performed? ------ Lysostaphin = Sensitive
MO = Negative
What are the results for micrococci when a lysostaphin and modified oxidase test are performed? ------ Lysostaphin = Resistant
MO = Positive
Are staph considered pathogenic? Are micrococci considered pathogenic? ------ Staph are pathogenic.
Micrococci are not usually.
Describe the appearance of staph. aureus on BAP (size, hemolysis, color) ------ med-lg, BH (NH) golden, cr, wh
What are the results for TC, SC, DNase and Novobiocin tests when run on staph. aureus; which is the most important test for this organism? ------ TC pos, SC pos, DNase pos, Novobiocin S
TC is the most important 'gold standard'
Describe the appearance of staph. epidermidis on BAP (hemolysis, size, color) ------ NH (BH), sm-med, wh-gr
Describe the appearance of staph. saprophyticus on BAP (hemolysis, size, color) ------ NH, lg, chalk-wt, possibly yellow or orange
What are the results for staph. epidermidis when TC, SC, DNase, and novobiocin tests are run? ------ TC neg, SC, neg, DNase neg, Novobiocin Sens
What are the results for staph. saprophyticus when TC, SC, Dnase, and novobiocin tests are run? ------ TC neg, SC neg, DNase neg, Novobiocin Resistant
Describe the principle of the TC test (and what positive and negative results appear as) ------ Detect primarily free coagulase. Coagulase binds w CRF. Complex reacts w fibrinogen forms fibrin clot.+ = clotted
Describe the principle of the SC test (and what + and - results appear as) ------ Detects bound coag. Coag interacts w fibrinogen forms fibrin clot.+ = agglut & background clearing; - = remains cloudy; rapid screen for aureus only
Describe the principle of the DNase test (toluidine blue) ------ Dye complex interacts with intact DNA. When DNA hydrolyzed, dye turns pink = +ve.
-ve if still blue
Describe the principle of the DNase test (HCl flood plate) ------ DNA in media when intact ppts (see cloudiness). If hydrolyzed, see clearing around organism.
What plates can you run a Novobiocin test on? ------ MH, or TS
Describe the latex agglutination test for s. aureus ------ Protein A of s. aureus binds with the IgG on the latex molecule.
Also can use to detect PbP2a (MRSA)
When do staph strains need to be typed (in what kind of cases)? (2) ------ Nosocomial infection or food poisoning
List 3 methods for epidemiological studies of s. aureus ------ PCR (molecular), bacteriophage/plasmid typing, antibiogram
Describe the main mechanisms of pathogenicity of staph. ------ Toxins: Hemolysins, enterotoxins
Enzymes: coagulase, fibrinolysin, thermonuclease; Adherence: biofilm
Drug resistance
Skin infections due to staph (5) ------ folliculitis, furuncle (boil), carbuncle, impetigo, abscess
Name 2 diseases of the respiratory system that staph. can cause ------ aspiration pneumonia (intubation) and hematogenous pneumonia
Name 3 diseases caused by disseminated toxins due to staph. ------ toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), food poisoning (heat stable enterotoxin)
Name 1 disease of the heart that staph can cause ------ Endocarditis (heart valves). can lead to DIC "bleeding out"
Are CNS pathogenic? If no, what are they and how do they gain entry? ------ No, opportunistic. Gain through medical indwelling devices.
Name 1 disease of the heart that CNS can cause ------ Prosthetic heart valve endocarditis
Name 1 disease of the brain/spinal cord that CNS can cause as a result of contamination during a specimen collection ------ Meningitis from CSF shunt
What diease is staph. saprophyticus most usually assoc with? ------ UTIs
What is the name of the enzyme that enables staph to become resistant to penicillins? ------ Penicillinase (type of B-lactamase)
If a staph tests 'S' to penicillin can you report this immediately? ------ no, must run another test to check for inducible resistance.
What drug was developed to 'beat out' the resistance to penicillins; is this effective on MRSA ------ Oxacillins; no MRSA are resistant
How are MRSA penicillin resistant ------ They have an altered PBP site (PBP2a)
What is the drug of choice for treating MRSA? ------ Vancomycin
What does heteroresistance mean? Which bacteria (scientific name) exhibit this trait? ------ Sensitive and resistant cells within the same culture; MRSA
What can be done to enhance the recovery of MRSA (enable it's detection in the lab) - 3 things ------ Increase salt, lower temperature, increase incubation time
Staph. lugdunensis can be found where on the body? What are the results for SC and PYR? ------ groin, PYR pos, SC pos
Staph. schleiferi is becoming a problem for what type of infection? What are the results for SC and PYR? ------ Nosocomial (from medical indwelling devices) SC pos, PYR pos
How are strep different than staph? (appearance) ------ Strep are smaller, translucent
What type of atmosphere do strept require (oxygen/carbon usage/tolerance) ------ Facultative anaerobe, also fermentative
What are the results for oxidase and catalase for strep ------ neg and neg (catalase neg differentiates them from staph which are cat +)
Describe the appearance of BH strep groups ACG on BAP and on slide ------ wide band BH, small colony, (A may be 'pushy') translucent; gpc pr, ch
Describe the appearance of BH strep group B on BAP and on slide ------ narrow band BH, lg colony, transl, may be orange; gpc pr, ch (string of pearls poss from broth)
Where are strep groups CG normally found? ------ as normal flora in URT, GIT
Is group A considered normal flora? ------ no, 'carrier' if it's present.
Where are strep group B usually found ------ as normal flora in GIT and female RT
Describe latex agglutination (acid) ------ acid + test isolate + neutralizer + ab-latex
pos if agglutin & background clearing; neg if cloudy; tests for ABCFG; fast
Describe latex agglutination (enzyme) ------ enzyme (pronase B) + test isolate; incubate; pos if agglut and bg clearing; can test for ABCDFG but must wait for incub.
List at least 2 drugs held in reserve to treat MRSA ------ Daptomycin, Linezolid, Synercid, Ortavancin
What are the 2 hemolysins that Group A strep can have? ------ Streptolysin O = oxygen labile (dies from O2 exposure)
Streptolysin S = oxygen stabile
What tests would you perform to ID a group A strep? and what is the organism's scientific name if IDed biochemically? ------ Catalase neg, (see wide band BH), bacitracin (S), PYR (+) or can do lancefield latex agglu at end to confirm; s. pyogenes
Name 5 mechanisms of pathogenicity of strep group A ------ toxins (hemolysins O,S; pyogenic - flesh eat, erythrogenic - scarlet fever); enzymes, adherence, capsule (hyaluronic acid), mimicry
Name some clinical manifestations as a result of strep gr A infection ------ pharyngitis, cellulitis, erysipelas, impetigo, necrotizing fascitis, 2 sequelae (rheumatic fever, acute glomerulonephritis)
What is the name of the test that can detect for a strep gr A infection (usually for post infection) ------ Antistreptolysin O
What class of abx are most strep gr A sensitive to. ------ penicillins
What is the (general) principle of the PYR test ------ detects an enzyme. if pos, see pink
How does bacitracin work (mechanism against bacteria)? how is it administered? ------ Works on cell wall; topical use only; too toxic for ingestion
How can you detect/grow gr A strep containing streptolysin O? ------ Stab media to provide anaerobic environment.
What tests would you run to ID a group C or G strep? ------ Cat neg, (wide band BH), bacitracin R, latex CG
What are the clinical implications of strep gr C and G? how is it similar to group A? how is it different? ------ same as group A but doesn't cause 2 sequelae; considered pathogenic when predominant in throat swab
Are group C/G strep pathogenic? If not what are they? ------ No, opportunistic
What tests would you run to ID a group B strep? ------ Cat neg, (narrow band BH), CAMP pos
Name 2 other tests that can be run to ID a group B strep ------ Hippurate
Columbia agar deep (pos if see orange pigment in stab lines; starch user)
Describe the CAMP test ------ CAMP produced by gr B strep interacts with staph hemolysin and causes hemolysis.
pos if see arrowhead pointing to staph streak.
Describe the hippurate test ------ Na-hippurate + isolate; incubate (gr B produces glycine); ninhydrin + glycine = purple = pos
What are the clinical manifestations of group B strep ------ Affects newborns; can cause pneumonia
What class of abx are strep gr B resistant to? ------ aminoglycosides

Side A ------ Side B
Describe the appearance of staphylococci on a smear? (gram +/- and what arrangement) ------ gpc, pr, cl
Describe the appearance of micrococci on a smear? (gram +/- and what arrangement, size) ------ gpc, TETRADS!!! (this distinguishes micrococci from staphylococci), they are also larger than staph.
Describe the appearance of staphylococci on BAP (poss colors, poss hemolyses) ------ cream, golden, white, BH or NH, op
Describe the appearance of micrococci on BAP (color) ------ stable pigment, can be carotenoid (yellow or red) esp at lower temps
What kind of atmosphere do staph. require? (ie. what are they in terms of oxygen/carbon tolerance/use) ------ Facultative ANAEROBE
What kind of atmosphere do micrococci require? (ie. what are they in terms of oxygen/carbon tolerance/use) ------ AEROBES
What are the results for staph when a lysostaphin and modified oxidase test are performed? ------ Lysostaphin = Sensitive
MO = Negative
What are the results for micrococci when a lysostaphin and modified oxidase test are performed? ------ Lysostaphin = Resistant
MO = Positive
Are staph considered pathogenic? Are micrococci considered pathogenic? ------ Staph are pathogenic.
Micrococci are not usually.
Describe the appearance of staph. aureus on BAP (size, hemolysis, color) ------ med-lg, BH (NH) golden, cr, wh
What are the results for TC, SC, DNase and Novobiocin tests when run on staph. aureus; which is the most important test for this organism? ------ TC pos, SC pos, DNase pos, Novobiocin S
TC is the most important 'gold standard'
Describe the appearance of staph. epidermidis on BAP (hemolysis, size, color) ------ NH (BH), sm-med, wh-gr
Describe the appearance of staph. saprophyticus on BAP (hemolysis, size, color) ------ NH, lg, chalk-wt, possibly yellow or orange
What are the results for staph. epidermidis when TC, SC, DNase, and novobiocin tests are run? ------ TC neg, SC, neg, DNase neg, Novobiocin Sens
What are the results for staph. saprophyticus when TC, SC, Dnase, and novobiocin tests are run? ------ TC neg, SC neg, DNase neg, Novobiocin Resistant
Describe the principle of the TC test (and what positive and negative results appear as) ------ Detect primarily free coagulase. Coagulase binds w CRF. Complex reacts w fibrinogen forms fibrin clot.+ = clotted
Describe the principle of the SC test (and what + and - results appear as) ------ Detects bound coag. Coag interacts w fibrinogen forms fibrin clot.+ = agglut & background clearing; - = remains cloudy; rapid screen for aureus only
Describe the principle of the DNase test (toluidine blue) ------ Dye complex interacts with intact DNA. When DNA hydrolyzed, dye turns pink = +ve.
-ve if still blue
Describe the principle of the DNase test (HCl flood plate) ------ DNA in media when intact ppts (see cloudiness). If hydrolyzed, see clearing around organism.
What plates can you run a Novobiocin test on? ------ MH, or TS
Describe the latex agglutination test for s. aureus ------ Protein A of s. aureus binds with the IgG on the latex molecule.
Also can use to detect PbP2a (MRSA)
When do staph strains need to be typed (in what kind of cases)? (2) ------ Nosocomial infection or food poisoning
List 3 methods for epidemiological studies of s. aureus ------ PCR (molecular), bacteriophage/plasmid typing, antibiogram
Describe the main mechanisms of pathogenicity of staph. ------ Toxins: Hemolysins, enterotoxins
Enzymes: coagulase, fibrinolysin, thermonuclease; Adherence: biofilm
Drug resistance
Skin infections due to staph (5) ------ folliculitis, furuncle (boil), carbuncle, impetigo, abscess
Name 2 diseases of the respiratory system that staph. can cause ------ aspiration pneumonia (intubation) and hematogenous pneumonia
Name 3 diseases caused by disseminated toxins due to staph. ------ toxic shock syndrome (TSST-1), scalded skin syndrome (exfoliative toxin), food poisoning (heat stable enterotoxin)
Name 1 disease of the heart that staph can cause ------ Endocarditis (heart valves). can lead to DIC "bleeding out"
Are CNS pathogenic? If no, what are they and how do they gain entry? ------ No, opportunistic. Gain through medical indwelling devices.
Name 1 disease of the heart that CNS can cause ------ Prosthetic heart valve endocarditis
Name 1 disease of the brain/spinal cord that CNS can cause as a result of contamination during a specimen collection ------ Meningitis from CSF shunt
What diease is staph. saprophyticus most usually assoc with? ------ UTIs
What is the name of the enzyme that enables staph to become resistant to penicillins? ------ Penicillinase (type of B-lactamase)
If a staph tests 'S' to penicillin can you report this immediately? ------ no, must run another test to check for inducible resistance.
What drug was developed to 'beat out' the resistance to penicillins; is this effective on MRSA ------ Oxacillins; no MRSA are resistant
How are MRSA penicillin resistant ------ They have an altered PBP site (PBP2a)
What is the drug of choice for treating MRSA? ------ Vancomycin
What does heteroresistance mean? Which bacteria (scientific name) exhibit this trait? ------ Sensitive and resistant cells within the same culture; MRSA
What can be done to enhance the recovery of MRSA (enable it's detection in the lab) - 3 things ------ Increase salt, lower temperature, increase incubation time
Staph. lugdunensis can be found where on the body? What are the results for SC and PYR? ------ groin, PYR pos, SC pos
Staph. schleiferi is becoming a problem for what type of infection? What are the results for SC and PYR? ------ Nosocomial (from medical indwelling devices) SC pos, PYR pos
How are strep different than staph? (appearance) ------ Strep are smaller, translucent
What type of atmosphere do strept require (oxygen/carbon usage/tolerance) ------ Facultative anaerobe, also fermentative
What are the results for oxidase and catalase for strep ------ neg and neg (catalase neg differentiates them from staph which are cat +)
Describe the appearance of BH strep groups ACG on BAP and on slide ------ wide band BH, small colony, (A may be 'pushy') translucent; gpc pr, ch
Describe the appearance of BH strep group B on BAP and on slide ------ narrow band BH, lg colony, transl, may be orange; gpc pr, ch (string of pearls poss from broth)
Where are strep groups CG normally found? ------ as normal flora in URT, GIT
Is group A considered normal flora? ------ no, 'carrier' if it's present.
Where are strep group B usually found ------ as normal flora in GIT and female RT
Describe latex agglutination (acid) ------ acid + test isolate + neutralizer + ab-latex
pos if agglutin & background clearing; neg if cloudy; tests for ABCFG; fast
Describe latex agglutination (enzyme) ------ enzyme (pronase B) + test isolate; incubate; pos if agglut and bg clearing; can test for ABCDFG but must wait for incub.
List at least 2 drugs held in reserve to treat MRSA ------ Daptomycin, Linezolid, Synercid, Ortavancin
What are the 2 hemolysins that Group A strep can have? ------ Streptolysin O = oxygen labile (dies from O2 exposure)
Streptolysin S = oxygen stabile
What tests would you perform to ID a group A strep? and what is the organism's scientific name if IDed biochemically? ------ Catalase neg, (see wide band BH), bacitracin (S), PYR (+) or can do lancefield latex agglu at end to confirm; s. pyogenes
Name 5 mechanisms of pathogenicity of strep group A ------ toxins (hemolysins O,S; pyogenic - flesh eat, erythrogenic - scarlet fever); enzymes, adherence, capsule (hyaluronic acid), mimicry
Name some clinical manifestations as a result of strep gr A infection ------ pharyngitis, cellulitis, erysipelas, impetigo, necrotizing fascitis, 2 sequelae (rheumatic fever, acute glomerulonephritis)
What is the name of the test that can detect for a strep gr A infection (usually for post infection) ------ Antistreptolysin O
What class of abx are most strep gr A sensitive to. ------ penicillins
What is the (general) principle of the PYR test ------ detects an enzyme. if pos, see pink
How does bacitracin work (mechanism against bacteria)? how is it administered? ------ Works on cell wall; topical use only; too toxic for ingestion
How can you detect/grow gr A strep containing streptolysin O? ------ Stab media to provide anaerobic environment.
What tests would you run to ID a group C or G strep? ------ Cat neg, (wide band BH), bacitracin R, latex CG
What are the clinical implications of strep gr C and G? how is it similar to group A? how is it different? ------ same as group A but doesn't cause 2 sequelae; considered pathogenic when predominant in throat swab
Are group C/G strep pathogenic? If not what are they? ------ No, opportunistic
What tests would you run to ID a group B strep? ------ Cat neg, (narrow band BH), CAMP pos
Name 2 other tests that can be run to ID a group B strep ------ Hippurate
Columbia agar deep (pos if see orange pigment in stab lines; starch user)
Describe the CAMP test ------ CAMP produced by gr B strep interacts with staph hemolysin and causes hemolysis.
pos if see arrowhead pointing to staph streak.
Describe the hippurate test ------ Na-hippurate + isolate; incubate (gr B produces glycine); ninhydrin + glycine = purple = pos
What are the clinical manifestations of group B strep ------ Affects newborns; can cause pneumonia
What class of abx are strep gr B resistant to? ------ aminoglycosides