Streptococcus, Enterococcus and Similar Organisms
Sodium desoxycholate
10% solution that induces autolytic process of S. pneumoniae, interacts with organisms amidase present in cells. (bile solubility)
Serologic Response in Rheumatic fever
ASO, anti-hylauronidase, and/or anti-DNase positive
M protein
Affect the pathogenesis of rheumatic fever and glomerulonephritis, not present in any other Lancefield group (B), highly variable with greater than 100 serotypes.
Serologic Response in Glomerulonephritis
Anti-hylauronidase, and/or anti-DNase positive (No ASO, oxygen labile, skin is exposed to air, most common following skin infections)
Lancefield Group
Beta-hemolytic streptococci are classified based on cell wall carbohydrates. Some are opportunistic pathogens where as others are clearly clinically significant.
Group D streptococcus
Bile esculin positive, will not grow in NaCl (enterococci are salt tolerant)
Bile Solubility Test
Bile or a solution of a bile salt (sodium deoxycholate) rapidly lyses pneumococcal colonies. Lysis depends on the presence of an intracellular autolytic enzyme, amidase.
CAMP Test
Christie, Atkins, Munch-Peterson test used to differentiate Group B, S. agalactiae from other streptococal species. Listeria monocytogenes also produces a positive CAMP reaction. The organisms produce a CAMP factor hemolytic protein that acts synergistically with the beta-lysin of S. aureus producing an enhanced arrowhead of hemolysis.
S. pneumoniae
Colonizer of the nasopharynx, person to person or contaminated respiratory secretions for transmission. Causes pneumoniae when accumulation occurs in the lower respiratory tract. Alpha hemolytic
SXT Agar
Common selective media for isolating Group A streptococci from throat swabs. 5% sheep blood supplemented with trimethoprim-sulfamethoxazole to suppress the growth of normal flora.
Phosphorylcholine
Contained in the cell wall of S. pneumoniae, binds the receptors of the platelet-activating factor in endothelial cells, WBC's, platelets and tissue cells of lungs and meninges, facilitating entry of the organism and spread.
BHI 6.5% Salt Tolerance
Differentiates Enterococcus species from viridans streptococcus. Enterococcus is positive for growth, viridans streptococcus are negative for growth.
Glomerulonephritis
Edema, hypertension, hematuria, and proteinuria, can follow either respiratory or cutaneous infections but more often the later. Results from antigen-antibody complexes deposited in the kidneys.
Incubation Conditions
Enriched CO2, 5-10% 35-37 degrees Celsius.
Alpha hemolytic, Bile esculin positive, Salt Tolerant, PYR Positive, mannitol positive
Enterococcus
Limitation of Bile Solubility
Enzyme activity may be reduced in old cultures, therefore negative results with colonies resembling S. pneumoniae should be confirmed with alternate methods.
Optochin (Taxo P)
Ethylhyrocupriene hydrochloride S. pneumoniae susceptible (positive) and S. pyogenes resistant (negative) Optochin interferes with the ATPase production of ATP in microorganisms. Zone of 14-16 mm is considered susceptible and presumptive identification of S. pneumoniae. May be considered confirmatory in the teaching lab when instructed to do a manual identification only.
CAMP Factor
Extracellular protein produced by S. agalactiae, acts synergistically with beta-lysin positive S. aureus producing enhanced hemolysis.
Rheumatic fever
Fever, endocarditis (cross reactivity with M protein in heart muscle), subcutaneous nodules and poly arthritis, usually follows respiratory infection.
Gram stain morphology
Gram positive cocci in chains or pairs. The cells only divide along the single axis. Typically round or oval, occassionally they will form elongated cells, especially following antibiotic treatment of a patient.
Hippurate hydrolysis
Group B, S. agalactiae and L. monocytogenes is hippuricase positive, hippuric acid is hydrolyzed (positive reaction is purple) visualized with the addition of ninhydrin
40% Bile
Inhibits most gram positive cocci except enterococci and group D streptococci
40% Bile
Inhibits most gram positive cocci except enterococci and group D streptococci.
Bacitracin sensitive
Micrococcus and Streptococcus pyogenes
Streptococcus dysgalactiae subsp. equisimilis
Mimics S. pyogenes and has been associated with the development of rheumatic fever
Streptococcus dysgalactiae subsp. equisimilis
Mimics S. pyogenes and has been associated with the development of rheumatic fever.
Enterococcus spp.
Normal microbiota of humans, animals and birds. Both E. facium and E. faecalis are normal flora of the human gastrointestinal tract and female genitourinary tract. Endogenous, person to person transmission or contaminated medical equipment. Gamma, alpha or rarely beta-hemolytic.
S. agalactiae
Normal microbiota of the female genital tract and the lower gastrointestinal tract; endogenous, person to person transmission or unwashed hands and direct contact. Narrow zone beta hemolysis
Viridans streptococci
Normal microbiota of the oral cavity, gastrointestinal tract, female genital tract. Endogenous gain access to sterile sites often from dental manipulations. Alpha hemolytic but may be beta-hemolytic
S. pyogenes
Not considered normal microbiota, nasal carriage, pharangeal, almost always clinically significant, person to person or aersolized droplet transmission. Beta-hemolytic
Ethylhydrocuperine hydrochloride
Optochin
Groups C, F, G
Other beta-hemolytic streptococci that are normal microbiota of the skin, nasopharynx, gastrointestinal and genital tract. Endogenous, person to person transmission
Bile Esculin
Presumptive identification of Enterococcus spp. Gram positive bacteria other than some streptococci and enterococci are inhibited by the bile salts in this media. The biochemical is the hydrolysis of esculin to esculetin that reacts with Fe3+ to form a black precipitate.
Ferric ammonium citrate
Produces black/brown precipitate when esculin is hydrolyzed
Ferric ammonium citrate
Produces black/brown precipitate when esculin is hydrolyzed.
Hippurate Hydrolysis
Production of hippuricase hydrolyzes hippuric acid producing glycine and benzoic acid. The glycine is then deaminated by the addition of ninhydrin and then the ninhydrin is oxidized producing a purple product. Differentiates S. agalactiae (positive) from S. pyogenes (negative)
Beta hemolytic, PYR negative, VP negative Resistant to bacitracin and CAMP positive
S. agalactiae
Neonatal Infection
S. agalactiae infection occurs during or before birthing process. May cause septicemia, pneumonia and meningitis in newborns.
Alpha hemolytic, mannitol positive, PYR negative, urease negative
S. mutans (Viridans streptococci)
Alpha hemolytic, bile solubility positive, optochin sensitive
S. pneumoniae
D Zone
S. pneumoniae or other beta hemolytic streptococci that are resistant to erythromycin and either susceptible or intermediately resistant to clindamycin should be examined for inducible clindamycin resistance. 5% Sheep blood agar is required for the media.
PYR positive
S. pyogenes, (y)Enterococcus spp., and S. (r)lugdunensis.
PYR positive
S.lugdunensis, Enterococcus spp., S. pyogenes
Beta hemolytic, PYR positive Bacitracin sensitive, VP negative
S.pyogenes (Group A)
Streptococcal pyrogenic exotoxins
SPES produce scarlet fever, maifested in streptococcal pharyngitis, rash on the face and upper trunk. Erythorgenic toxins produced by lysogenic strains (Bacteriophage containing)
Enterococcosel agar
Selective and differential medium based on the esculin hydrolysis and selective by the incorporation of bile salts to inhibit the growth of other gram positive organisms, with the exception of Group D streptococci.
Catalase negative Gram positive cocci
Streptococcus and Enterococcus species
Catalase negative gram positive cocci
Streptococcus and Enterococcus species
Other Gram positive cocci test methods
These were all described and included in the staphylococci chapter quizlet.
LIM Broth
Todd Hewitt broth with CNA, selective enrichment for Group B, S. agalactiae
LIM Broth
Todd-Hewitt Broth with Colistin and Nalidixic Acid inhibits the growth of gram negative bacteria and normal vaginal flora. Selectively used to isolate group B streptococci from clinical specimens.
6.5% NaCl
Used to determine salt tolerance, Enterococci are able to grow, most other streptococci and Group D enterococci (previously streptococci) are unable to grow.
Pneumolysin
Virulence factor produced by S. pneumoniae, that activates classic complement pathway. Suppresses oxidative burst in phagocytes, provding evasion of the immune system.
CAMP Factor
extracellular protein produced by S. agalactiae, acts synergistically with beta-lysin positive S. aureus producing enhanced hemolysis (CAMP fire)
Streptolysin O
oxygen labile, immunogenic, capable of lysing same cell types of Streptolysin O. S. pyogenes. Also inhibited by cholesterol in skin lipids, which also accounts for the reason skin infections do not result in the production of antistreptolysin O antibodies
Streptolysin S
oxygen stable, non-immunogenic hemolysin capable of lysing RBC's, WBC's and platelets in room air. S. pyogenes
Streptococcus pseudopneumoniae
treptococcus pseudopneumoniae is a recently described member of the Streptococcus mitis/oralis group of viridans Streptococci that shares some characteristics with S. pneumoniae1. Key features of S. pseudopneumoniae are the absence of pneumococcal capsule, insolubility in bile, resistance or indeterminate susceptibility to optochin when incubated in 5 per cent CO2 but susceptibility to optochin when incubated in ambient air, positive reactions in DNA probe hybridization and antigen detection
Group D streptococcus
►+ Bile esculin positive ►- Will not grow in NaCl (enterococci are salt tolerant).
Bile solubility (sodium deoxycholate)
►10% solution that induces autolytic process of S. pneumoniae. ►Interacts with organisms amidase present in cells.
Serologic Response in Rheumatic fever
►ASO. ►Anti-hyaluronidase and/or anti-DNase positive.
M protein
►Affect the pathogenesis of rheumatic fever and glomerulonephritis, not present in any other Lancefield group (B). ►Highly variable with greater than 100 serotypes.
Streptococcus mutans (Viridans streptococci)
►Alpha hemolytic. ►Gram POSITIVE cocci in chains. ►Lancefield non-groupable. ►+ Mannitol POSITIVE. ►- PYR negative. ►- Urease negative.
Serologic Response in Glomerulonephritis
►Anti-hyaluronidase, and/or anti-DNase positive. ►Most common following skin infections. ►NO ASO, oxygen labile, skin is exposed to air.
Lancefield Group
►Beta-hemolytic streptococci are classified based on cell wall carbohydrates. ►Some are opportunistic pathogens whereas others are clearly clinically significant.
Streptococcus pneumoniae
►Colonizer of the nasopharynx. ►Person to person or contaminated respiratory secretions for transmission. ►Causes pneumoniae when accumulation occurs in the lower respiratory tract; rust colored sputum. ►Alpha hemolytic. ►Gram POSITIVE lancet-shaped diplococci. ►+ Bile solubility POSITIVE. ►S Optochin sensitive.
SXT Agar
►Common selective media for isolating Group A streptococci from throat swabs. ►5% sheep blood supplemented with trimethoprim-sulfamethoxazole to suppress the growth of normal flora.
Phosphorylcholine
►Contained in the cell wall of S. pneumoniae. ►Binds the receptors of the platelet-activating factor in endothelial cells, WBCs, platelets and tissue cells of lungs and meninges, facilitating entry of the organism and spread.
Acute (Post-streptococcal) Glomerulonephritis
►Edema, hypertension, hematuria, and proteinuria. ►Can follow either respiratory or cutaneous infections but more often the later. ►Results from antigen-antibody complexes deposited in the kidneys.
Streptococcus Incubation Conditions
►Enriched CO2: 5-10%. ►35-37 degrees Celsius.
Rheumatic fever
►Fever, endocarditis (cross reactivity with M protein in heart muscle), subcutaneous nodules and polyarthritis. ►Usually follows respiratory infection.
Streptococcus Gram stain morphology
►Gram positive cocci in chains or pairs. ►Cells only divide along the single axis. ►Typically round or oval, occasionally they will form elongated cells, especially following antibiotic treatment of a patient.
Hippurate hydrolysis positive
►Group B, S. agalactiae, and L. monocytogenes is hippuricase positive. ►Hippuric acid is hydrolyzed (positive reaction is purple) visualized with the addition of ninhydrin.
Enterococcus spp.
►Normal microbiota of humans, animals and birds. ►Both E. faecium and E. faecalis are normal flora of the human gastrointestinal tract and female genitourinary tract. ►Endogenous, person to person transmission or contaminated medical equipment. ►Gamma, alpha or rarely beta-hemolytic. ►+ Bile esculin POSITIVE ►Growth 6.5% NaCl ►+ PYR Positive. ►+ Mannitol POSITIVE.
Streptococcus agalactiae
►Normal microbiota of the female genital tract and the lower gastrointestinal tract. ►Endogenous, person to person transmission or unwashed hands and direct contact. ►Narrow zone beta hemolysis. ►- PYR negative. ►- VP negative ►R Bacitracin Resistant ►+ CAMP positive
Viridans streptococci
►Normal microbiota of the oral cavity, gastrointestinal tract, female genital tract. ►Endogenous gain access to sterile sites often from dental manipulations. ►Alpha hemolytic but may be beta-hemolytic.
Streptococcus pyogenes (Group A Strep)
►Not considered normal microbiota. ►Nasal carriage, pharyngeal, almost always clinically significant. ►Person to person or aerosolized droplet transmission. ►Beta-hemolytic. ►- Catalase negative ►+ PYR positive ►S BAcitracin Susceptible ►- VP negative
Groups C, F, G
►Other beta-hemolytic streptococci that are normal microbiota of the skin, nasopharynx, gastrointestinal and genital tract. ►Endogenous, person to person transmission.
Streptolysin O
►Oxygen labile, immunogenic hemolysin, capable of lysing RBCs, WBCs and platelets in anaerobic environments. ►S. pyogenes. ►Also inhibited by cholesterol in skin lipids, which also accounts for the reason skin infections do not result in the production of antibodies to this hemolysin.
Streptolysin S
►Oxygen stable, non-immunogenic hemolysin capable of lysing RBCs, WBCs and platelets in room air. ►S. pyogenes.
Streptococcal Pyrogenic Exotoxins (SPEs)
►Produce scarlet fever. ►Manifested in streptococcal pharyngitis, rash on the face and upper trunk. ►Erythrogenic toxins produced by lysogenic, bacteriophage containing, strains.
Streptococcus pseudopneumoniae
►Recently described member of the Streptococcus mitis/oralis group of viridans Streptococci that shares some characteristics with S. pneumoniae. ►Key features are: ○Absence of pneumococcal capsule. ○Insolubility in bile. ○Resistance or indeterminate susceptibility to optochin when incubated in 5% CO2 but susceptibility to optochin when incubated in ambient air. ►Positive reactions in DNA probe hybridization and antigen detection.
Group B Strep Neonatal Infection
►S. agalactiae infection occurs during or before birthing process. ►May cause septicemia, pneumonia and meningitis in newborns.
D-zone test
►S. pneumoniae or other beta hemolytic streptococci that are resistant to erythromycin and either susceptible or intermediately resistant to clindamycin. ►Should be examined for inducible clindamycin resistance. ►5% Sheep blood agar is required for the media.
Enterococcosel agar
►Selective and differential medium based on the esculin hydrolysis. ►Selective by the incorporation of bile salts to inhibit the growth of other gram positive organisms, with the exception of Group D streptococci.
LIM Broth
►Todd-Hewitt Broth with Colistin and Nalidixic Acid. ►Inhibits the growth of gram negative bacteria and normal vaginal flora. ►Selective enrichment used to isolate Group B streptococci from clinical specimens.
6.5% NaCl
►Used to determine salt tolerance. ►Enterococci are able to grow. ►Most other streptococci and Group D enterococci (previously streptococci) are unable to grow.
Pneumolysin
►Virulence factor produced by S. pneumoniae, that activates classical complement pathway. ►Suppresses oxidative burst in phagocytes, providing evasion of the immune system.