This chapter covers the bacterial genera that are taxonomically diverse and belong to the families
Cardiobacteriaceae
,
Flavobacteriaceae
,
Leptotrichiaceae
,
Neisseriaceae
,
Pasteurellaceae
, and
Porphyromonadaceae
; common traits justify their discussion as a group. The taxonomy of the family
Pasteurellaceae
has undergone important changes; the family consists of over 100 named species distributed in over 25 genera, of which 4 include human pathogens:
Actinobacillus
,
Aggregatibacter
,
Haemophilus
, and
Pasteurella
. The chapter focuses on species commonly isolated from humans. Direct microscopy of specimens or of positive blood cultures supported by clinical information may help identify the corresponding bacteria, e.g., the typical morphology of spindle‐shaped cells in the Gram stain in the context of a dog bite allows the presumptive identification of
C. canimorsus
. Phenotypic identification of fastidious Gram‐negative rods presents several challenges.