Neisseria spp

• N. bacilliformis
• N. cinera
• N. elongata
• N. flavescens
• N. lactamica
• N. mucosa
• N. polysaccharea
• N. sicca
• N. subflava

Gram Stain

• Gram negative diplococci (except N. bacilliformis and N. elongata - bacilli) (aerobic)

Clinical Significance

These organisms are part of human commensal oropharyngeal flora.

They are considered low level pathogens but have been implicated in endocarditis (native and prosthetic valve), septicemia, meningitis, peritonitis, septic arthritis, osteomyelitis, pneumonia, and empyema typically in immunocompromised/predisposed individuals.

Usual Susceptibility Pattern

These organisms are generally susceptible to penicillins and cephalosporins, tetracyclines, quinolones, and TMP/SMX.

Penicillin resistance has rarely been described in N. lactamica, N. flavescens, and N. polysaccharea.