Deep neck spaces are regions of loose connective tissue filling areas between the 3 layers of deep cervical fascia, namely, superficial, middle, and deep layers. The superficial layer is the investing layer, The pretracheal layer is the intermediate layer and the prevertebral layer is the deepest layer. Deep neck space infection (DNI) is defined as an infection in the potential spaces and actual fascial planes of the neck. Once the natural resistance of fascial planes is overcome, spread of infection occurs along communicating fascial boundaries. More recent trends include the increasing prevalence of resistant bacterial strains, a decline in DNIs caused by pharyngitis or tonsillitis, and a relative increase in DNIs of odontogenic origin. Most DNIs are polymicrobial. Only 5% are purely aerobic and 25% with isolated anaerobes. The epidemiology of DNIs needs to be monitored for changing trends and the impact of underlying host immunity and developing microbial multidrug resistance is established. Surveillance at laboratory level should include mandatory susceptibility testing of all empiric antibiotics against microbes commonly identified in adult DNI microscopy, culture, and sensitivity (MC&S) specimens. The role of susceptibility testing of microbes not commonly identified in adult DNI MC&S specimens needs further review, on a clinical case-by-case basis.