An 8-Month Old Infant Has Been Brought to the ER

Multiple Choice

An 8-month old infant has been brought to the ER with a high fever.Her parents indicate that she has not been eating or drinking well and has been very irritable until the last few hours during which she has been only minimally responsive.Suspecting meningitis, a spinal tap is done and the CSF sample is sent to the lab for analysis.The white blood cell count on the sample is profoundly elevated, the protein content is elevated, and the glucose level is depressed.The Gram stained smear shows gram-positive cocci in pairs.Cultures are done and after overnight incubation, alpha hemolytic colonies are observed on the blood plate.These colonies contain gram-positive cocci, which are catalase negative.An optochin susceptibility test is done and there is a large zone of inhibition around the disk.What is the identification of this isolate?

A) Streptococcus pneumoniae
B) viridans Streptococci
C) Enterococcus faecalis
D) Neisseria meningitidis
E) Streptococcus agalactiae