Final answer:
To differentiate Moraxella catarrhalis from Neisseria, laboratory tests such as sugar fermentation, the oxidase test, and colony morphology on agar plates are used. Neisseria requires specific growth conditions and metabolizes glucose and maltose, while Moraxella catarrhalis does not ferment sugars and is DNase positive.
Step-by-step explanation:
To differentiate Moraxella catarrhalis from Neisseria species, a few key laboratory tests can be utilized. First, while both are gram-negative diplococci, Neisseria shows a coffee bean shape under microscopic examination and is often more demanding to culture, requiring a high level of moisture, carbon dioxide, and nutrient supplements. Neisseria species are also microaerophilic and thus need low levels of oxygen, favoring growth on chocolate agar made with partially hemolyzed red blood cells.
Moraxella catarrhalis is also oxidase positive like Neisseria. However, one biochemical difference is in sugar fermentation tests. Neisseria can metabolize glucose and maltose, while Moraxella does not ferment sugars. Additionally, Moraxella catarrhalis produces DNase and has distinctive morphology on agar plates, often appearing as grey, nonhemolytic colonies. The oxidase test followed by analysis of sugar utilization is commonly employed to discern between the two bacterial species.