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Streptococcus spp
SCC microbiology
Question | Answer |
---|---|
What hemolytic pattern is demonstrated by the Enterococci spp. on a BAP plate? | Gamma hemolysis: no hemolysis or discoloration on BAP |
What is the clinical significance of the Streptococcus viridens organisms? | Commonly associated with being a blood culture contaminant |
After streaking a BAP for isolation, why is it good technique to "stab" it 2-3 times in the first quadrant? | To enhance hemolytic pattern being demonstrated by Streptococcus spp. on BAP. |
What hemolytic pattern is demonstrated by Strep. pneumoniae on a BAP plate? | Alpha hemolysis: partical or incomplete hemolysis |
Are the Enterococci spp. considered normal flora? If so, where can these organisms be found on the human body? | Yes. normal intestinal flora |
What is the gram stain reaction and morphology of the Streptococcus spp? | gram positive cocci |
Describe what a beta hemolytic pattern looks like on a BAP plate. | Complete hemolysis which means there is complete lysis of the RBCs in the BAP. |
What Lancefield antigen grouping does Streptococcus pneumoniae possess? | Strep. pneumoniae has no Lancefield antigen grouping |
Describe what an alpha hemolytic pattern looks like on a BAP plate. | Partial or incomplete hemolysis meaning a greenish discoloration on the BAP. |
Which group of Streptococci/Enterococci spp. are capable of growing well in increased concentrations of bile salts and NaCl, and are also becoming a major problem in the hospital environment? | Group D Enterococci spp. |
How are Streptococcus organisms grouped using the Lancefield antigens? | Grouped by having the same Lancefield antigens located on their surface. |
Grouped by having the same Lancefield antigens located on their surface. | Capsule formation |
What is the clinical significance of Streptococcus agalactiae? | pneumonia, sepsis, meningitis in infants, puerperal fever (childbirth fever) |
Beta hemolysis on a BAP plate is caused by two substances that cause the complete lysis of RBCs. These substances are known as "hemolysins". Name the two hemolysins. | Streptolysin S and Streptolysin O |
What is the purpose of knowing about the Lancefield antigens? | Used as a technique to identify Streptococcus spp. |
Which of the following organisms are commonly associated with community-acquired pneumonia, and exhibit an alpha hemolytic pattern on a BAP plate? Streptococcus pyogenes, Streptococcus agalactiae Streptococcus pneumoniae, Enterococci spp. | Which of the following organisms are commonly associated with community-acquired pneumonia, and exhibit an alpha hemolytic pattern on a BAP plate? Streptococcus pyogenes, Streptococcus agalactiae Streptococcus pneumoniae, Enterococci spp. |
What hemolytic pattern is demonstrated by the Other Group D Enterococci spp on a BAP plate? | Either alpha or gamma hemolysis |
What is the clinical significance of Streptococcus pneumoniae? | Association: pneumonia, sinusitis, mastoiditis, meningitis, and endocarditis |
Where are the Lancefield antigens located on an organism? | Located on surface of organism. |
which stret spp. shows following characteristics: gpc implicated in pneumonia of newborns, puerperal fever in post-partum women, beta-hemolytic on BAP plate, CAMP test (+)? S.pyogenes, S.agalactiae,S.pneumonia, or Enterococci spp. | Streptococcus agalactiae |
Which of the common plated media is used to determine the hemolytic patterns of the Streptococus spp.? | BAP plate ONLY! |
What is the clinical significance of the Enterococci spp.? | What is the clinical significance of the Enterococci spp.? |
What type of designation is used to group the Lancefield antigens? | Alphabet: Group A, Group B, Group C, etc. |
What hemolytic pattern is demonstrated by Streptococcus agalactiae on a BAP plate? | Beta hemolysis: complete hemolysis |
After determining you are dealing with a Streptococcus spp. What is the next logical step in determining the proper identification of the organism? | Look at the hemolytic pattern demonstrated on a BAP plate. |
Are Streptococcus spp. considered normal flora? If so, where can they be found on the human body? | Yes. Found in respiratory, genital, and intestinal tracts. |
Are the Other Group D Enterococci spp. considered normal flora? If so, where can these organisms be found on the human body? | Are the Other Group D Enterococci spp. considered normal flora? If so, where can these organisms be found on the human body? |
Compromised hosts are: | Individuals who are more susceptible to opportunistic infections. |
What Lancefield antigen grp Strept spp. is responsible for the infection, Necrotizing fasciitis (infects muscle/fat) high death rate quick diagnosis, wound bebrided w/ antibiotics necessary | Group A Streptococcus spp. |
What is the clinical significance of Streptococcus pyogenes? | pharyngitis, rheumatic fever, glomerulonephritis, TSS, necrotizing fasciitis |
What Lancefield antigen grouping does Streptococcus pyogenes possess? | Group A Lancefield antigen grouping |
Describe what a gamma hemolytic pattern looks like on a BAP plate. | No hemolysis or discoloration seen on BAP plate. |
This organism is the most virulent species in the genus Streptococcus and is responsible for suppurative sequelae such as rheumatic fever and glomerulonephritis. | Streptococcus pyogenes |
What is the catalase reaction of the Streptococcus spp.? | Catalase negative |
What hemolytic pattern is demonstrated by Streptococcus pyogenes on a BAP plate? | Beta hemolysis: complete hemolysis on BAP plate |
What virulence factor do some Streptococcus agalactiae possess that protects them from phagocytosis? | Capsule formation |
What Lancefield antigen grouping does Streptococcus agalactiae possess? | Group B Lancefield antigen grouping |
Is Streptococcus pneumoniae considered normal flora? If so, where can it be found on the human body? | Yes. Normally found in respiratory tract of humans. |
What are the incubation requirements for Streptococcus spp.? | Incubation: 37C under increased CO2 concentration |
What is the clinical significance of the Other Group D Enterococci spp.? | bacteremia, sepsis in newborns, endocarditis and meningitis |
Name the three types of hemolytic patterns demonstrated by the Streptococcus spp. | Beta, Alpha, and Gamma (BAG-->to remember the order) |
What Lancefield antigen grouping do the Enterococci possess? | What Lancefield antigen grouping do the Enterococci possess? |
What type of environmental conditions are the Group D Enterococci spp. able to survive? | Survive in extreme environmental conditions like high % of bile salts & NaCl. |
What virulence factor do some Streptococcus pyogenes possess that protects them from phagocytosis? | Capsule formation |