CAMLPR Microbiology Practice Test

Carbohydrate utilization patterns distinguish Neisseria species. When testing sugar fermentation, Neisseria meningitidis typically ferments both glucose and maltose, giving positive results for both sugars. In contrast, Neisseria gonorrhoeae ferments glucose but not maltose, which helps separate the two pathogens in clinical samples. Moraxella catarrhalis is a Gram-negative diplococcus as well, but it does not consistently ferment glucose or maltose in these tests, so it doesn’t match the pattern described. Haemophilus influenzae is not a Neisseria species and has different growth and identification characteristics (it’s a small Gram-negative coccobacillus that requires X and V factors), so it wouldn’t be identified by these sugar fermentation results. Therefore, the organism that shows Gram-negative diplococci and ferments both glucose and maltose is Neisseria meningitidis.