What tests should be performed to identify B-hemolytic colonies of gram-positive cocci from a newborn with skin eruptions?

The identification of B-hemolytic colonies of gram-positive cocci, particularly in the context of a newborn presenting with skin eruptions, typically indicates the possible presence of Streptococcus agalactiae (Group B Streptococcus, or GBS). The most appropriate tests would assist in confirming the identity of the bacteria.

Primarily, coagulase testing is utilized to differentiate between Staphylococcus species rather than for streptococci, which makes this option less relevant in the context of B-hemolytic streptococci. Glucose fermentation is a metabolic test that showcases the ability of an organism to ferment glucose, which, while informative for various bacteria, does not specifically identify or confirm B-hemolytic streptococci effectively. DNase testing also serves a similar broad purpose but doesn't narrow down to the identification of Group B Streptococcus.

A more precise selection of tests such as bacitracin sensitivity for Group A Streptococcus or CAMP test for identifying Group B Streptococcus would yield better results. The CAMP test, for example, is essential because it shows a synergistic effect that differentiates Group B Streptococcus from other hemolytic streptococci. Therefore, a combination of tests focused