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?

Question

Quizplus · Accepted Answer

The presence of gram-positive cocci in pairs, elevated white blood cell count, elevated protein content and depressed glucose level in the CSF, and alpha hemolytic colonies on the blood plate are all consistent with a diagnosis of pneumococcal meningitis. Additionally, the optochin susceptibility test showing a large zone of inhibition around the disk is characteristic of Streptococcus pneumoniae. The other choices, while potentially causing meningitis, do not match all of the clinical and laboratory findings mentioned.

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