A gram-negative bacillus, Kingella denitrificans (K. denitrificans),
is a component of the normal upper respiratory and genitourinary
tract flora and sometimes causes severe infection [13e15]. Kingella
species are plump gram-negative bacilli and positive for cytochrome
c oxidase [16]. Unlike the related species, such as Neisseriae
and Moraxellae, Kingella species are catalase-negative similar to
Cardiobacterium hominis and Eikenella corrodens. However, strain
UB-75 of Kingella oralis and strain UB-204 of E. corrodens were
catalase positive [17]. The type-strain of K. denitrificans characteristically
produces acid from glucose and is positive for prolylaminopeptidase.
Different from other species in the genus,
K. denitrificans reduces nitrate to nitrite [16].