Chapter 8: Neisseria

Neisseria gonorrhoeae receives extensive coverage, with particular emphasis on the organism's ability to establish infection across diverse anatomical sites and its distinct presentations depending on host sex and age. The chapter details gonococcal urethritis and cervicitis as common manifestations, explores the serious complications of pelvic inflammatory disease that can develop in infected women, and addresses the distinct clinical picture of ophthalmia neonatorum in neonates exposed during delivery. Disseminated gonococcal infection represents a particularly severe systemic manifestation that warrants specific clinical attention. Throughout the analysis of both Neisseria species, the chapter emphasizes virulence mechanisms that enable these organisms to evade immune defenses, establish infection, and cause tissue damage. The final section transitions to Moraxella catarrhalis, characterizing this Gram-negative diplococcus as an opportunistic respiratory pathogen with its own complement of virulence determinants and toxin production capabilities. Diagnostic methodologies appropriate for identifying each organism are presented alongside current treatment protocols, including considerations for antimicrobial resistance patterns that increasingly impact therapeutic decision-making. The chapter integrates morphological and metabolic properties of these organisms with their clinical manifestations, providing students with a comprehensive framework for understanding how bacterial structure and physiology relate to disease mechanisms and laboratory identification strategies.