<prompt> Which stain is used for Corynebacterium diphtheriae ?GeimsaAlbePASIndia ink  <response>: Ans. is b i.e., AlbeThe diphtheria bacillus was first observed and described by Klebs 1883 but was first cultivated by Loeffler 1884.Therefore, it is known as Klebs - Loeffler bacillus KLB.Corynebacterium diphtheria is gram positive slender rod bacilli which is noncapsulated and non-motile.The bacilli are arranged in a characteristic fashion in smears, being at various angles to each other, resembling the letter V or L Chinese letter or .nneiform arrangement. There is chracteristic Clubbed appearance.Characteristic feature is irregular staining due to presence of granules, called Babes Ernest or volutin granules. These granules are also called metachromatic granules or polar bodies. 