09-09-2007, 11:39 AM
yes Bro, be careful
The correct answer is B.
Streptococcus agalactiae, the group B streptococcus, is the most common agent of meningitis in 5- to 30-day-olds. Most cases are due to capsule type III, which is very neurotropic. Identifying the organism can be difficult, but the CAMP test aids in
diagnosis. Alone, S. agalactiae strains produce a weak beta-hemolysis of sheep red blood cells. However, S.agalactiae produces a diffusible extracellular compound that, in conjunction with a specific beta-hemolysin of Staphylococcus aureus, will cause the complete lysis of
sheep red blood cells.
Bacitracin sensitivity (choice A) is used to distinguish Streptococcus pyogenes, the group A streptococcus, from other beta-hemolytic streptococci. S. pyogenes is sensitive to the antibiotic bacitracin. All other beta-hemolytic streptococci are resistant to the antibiotic.
The coagulase test (choice C) is used to distinguish between S. aureus and nonpathogenic staphylococci. A sample of the bacteria is inoculated into rabbit plasma. If the test is positive, a clot will form.
Growth on bile esculin agar (choice D) is used to identify the group D streptococci. Group D streptococci areable to grow in the presence of bile. They also have the ability to hydrolyze esculin.When esculin is hydrolyzed, it turns the media black. The other bacteria that are
capable of growing in the presence of bile cannot hydrolyze esculin.
Optochin sensitivity (choice E) is used to distinguish S.pneumoniae from other alpha-hemolytic streptococci. S. pneumoniae will lyse when it comes in contact with bile; the other alpha-hemolytic streptococci will not.
The correct answer is B.
Streptococcus agalactiae, the group B streptococcus, is the most common agent of meningitis in 5- to 30-day-olds. Most cases are due to capsule type III, which is very neurotropic. Identifying the organism can be difficult, but the CAMP test aids in
diagnosis. Alone, S. agalactiae strains produce a weak beta-hemolysis of sheep red blood cells. However, S.agalactiae produces a diffusible extracellular compound that, in conjunction with a specific beta-hemolysin of Staphylococcus aureus, will cause the complete lysis of
sheep red blood cells.
Bacitracin sensitivity (choice A) is used to distinguish Streptococcus pyogenes, the group A streptococcus, from other beta-hemolytic streptococci. S. pyogenes is sensitive to the antibiotic bacitracin. All other beta-hemolytic streptococci are resistant to the antibiotic.
The coagulase test (choice C) is used to distinguish between S. aureus and nonpathogenic staphylococci. A sample of the bacteria is inoculated into rabbit plasma. If the test is positive, a clot will form.
Growth on bile esculin agar (choice D) is used to identify the group D streptococci. Group D streptococci areable to grow in the presence of bile. They also have the ability to hydrolyze esculin.When esculin is hydrolyzed, it turns the media black. The other bacteria that are
capable of growing in the presence of bile cannot hydrolyze esculin.
Optochin sensitivity (choice E) is used to distinguish S.pneumoniae from other alpha-hemolytic streptococci. S. pneumoniae will lyse when it comes in contact with bile; the other alpha-hemolytic streptococci will not.
