Neisseria gonorrhoeae: mechanisms of immune evasion, antimicrobial resistance, and vaccine development challenges.

Neisseria gonorrhoeae is a strictly human-adapted Gram-negative bacterium and the causative agent of gonorrhoea, a sexually transmitted infection of major global health importance. Disease control is increasingly compromised by the rapid emergence of resistance to multiple antimicrobial classes and by the failure of natural infection to induce durable protective immunity. The ability of N. gonorrhoeae to persist within the host is driven by genetic and phenotypic adaptation strategies, including extensive antigenic and phase variation of surface-exposed components and a diverse array of immune evasion strategies. These include resistance to complement-mediated killing, manipulation of phagocytic cell function, suppression of adaptive immune responses, and mechanisms that overlap with antimicrobial resistance pathways. Experimental infection models have provided important insights into gonococcal pathogenesis and host immunity. Advances in vaccine research, including evidence of partial protection conferred by N. meningitidis group B outer membrane vesicle-based vaccines, have renewed interest in conserved gonococcal antigens and their use in multicomponent vaccine platforms. Identification of target antigens and immune pathways that confer protective immunity remain central to the development of effective vaccines against gonorrhoea and associated antimicrobial resistance.