Bile Esculin Agar Positive. The test is primarily used to differentiate bile soluble Streptococcus pneumoniae from bile insoluble alpha-hemolytic streptococci. Streptococcus pneumoniae is an oval diplococcus that is optochin sensitive, a- hemolytic and causes pneumonia, wound infections, meningitis, septicemia, and otitis media in children. Streptococcus pneumoniae (pneumococcus) Alpha Hemolysis on Blood Agar Optochin Negative. Enterococci is a significant cause of endocarditis with a high degree of mortality. Chuard C, Reller LB. Le T, Bhushan V. First Aid for the USMLE Step 1 2015. Bile esculin disk is used for the rapid detection of esculin hydrolysis in presence of bile for differentiating group D Streptococci from non-group D Streptococci. Bile esculin test. Principle Bile esculin test is based on the hydrolysis of esculin into glucose and esculetin (6, 7-dihydroxy-coumarin) by a micro-organism that produce an enzyme esculinase. S pneumoniae are non-beta-hemolytic streptococci that are optochin-positive, bile-soluble, and bile esculin-negative. Bile esculin azide agar uses sodium azide to inhibit Gram-negative bacteria, but we … The bile solubility test causes the lysis of: Optochin disk test, 5 μg/mL or less. Group B Streptococcus (S. agalactiae) Alpha Hemolysis on Blood Agar Optochin Sensitive. Streptococcus bovis. All strains of group D streptococci were bile-esculin positive. Streptococcus, viridans group. J. Clin. On solid media, pneumococci form alpha-hemolytic colonies with a depression in the center of the colony. This test along with Bile-Esculin test, is used in many laboratories to distinguish Enterococcus species from the group D streptococci, Streptococcus bovis and Streptococcus lactis. The bile solubility test has been used as an essential test for the differentiation of S. pneumoniae as it allows the distinction between the two species S. pneumoniae and Streptococcus pseudopneumoniae, which is a challenging task. The ability to hemolyze red blood cells varies among the species in the Streptococcus genus, and it is the first feature observed in species classification. PRINCIPLE Bile esculin medium contains esculin and peptone for nutrition and bile to inhibit Gram-positive bacteria other than Group D streptococci and enterococci. SeroSTAT reactions were falsely positive with 2 strains of S. sanguisII and 1 strain of Streptococcus MG (4.6% of all viridans streptococci tested) and falsely negative with 10 S. bovis, 8 S. faecalis, 1 S. durans, and 6 S. faecium strains (22.7% of all group D streptococci tested). Microbiol. ... Gamma Hemolysis on Blood Agar. The bile solubility test is a qualitative procedure for determining the ability of bacterial cells to lyse in the presence of bile salts under specific conditions of time and temperature. Bile solubility test is a biochemical test used for the differentiation and confirmation of Streptococcus pneumoniae from other alpha-hemolytic Streptococci.. Bile-Esculin Test for Presumptive Identification of Enterococci and Streptococci: Effects of Bile Concentration, Inoculation Technique, and Incubation Time. No Growth in BHI Broth with 6.5% NaCl. McGraw-Hill Education ; 2014 The plate below was streaked with Streptococcus pyogenes ; notice the large zone of inhibition surrounding the disk. Test used to differentiate the viridans streptococci from the group D streptococci and enterococci: Streptococcus pneumoniae colonies on a blood agar plate. This test is commonly used to distinguish between the b-hemolytic streptococci: Streptococcus agalactiae (bacitracin resistant) and Streptococcus pyogenes (bacitracin sensitive). 1998; 36 (4): p.1135-1136. In liquid media, S pneumoniae replicates in chains. CAMP Test Positive.