Neisseria gonorrheae Gonorrhea

Morphology and culture. Gonococci are Gram-negative, coffee-bean-shaped cocci that are usually paired and have a diameter of approximately 1 im (Fig. 4.16). Attachment pili on the bacterial cell surface are responsible for their adhesion to mucosal cells.

Gonococci can be grown on moist culture mediums enriched with protein (blood). The atmosphere for primary culturing must contain 5-10% CO2.

Pathogenesis and clinical picture. Gonorrhea is a sexually transmitted disease. The pathogens penetrate into the urogenital mucosa, causing a local purulent infection. In men, the prostate and epididymis can also become infected. In women, the gonococci can also cause salpingitis, oophoritis, or even peritonitis. Gonococci reaching the conjunctival membrane may cause a purulent conjunctivitis, seen mainly in newborn children. Gonococci can also infect the rectal or pharyngeal mucosa. Hematogenously disseminated gonococci may also cause arthritis or even endocarditis.

Determinants of the Pathogenicity of Gonococci

Attachment pili on the surface and the outer membrane protein Opa are responsible for adhesion to cells of the urogenital tract. Opa also directs the invasion process by means of endocytosis. Immune defenses against granulocytes are based on the outer membrane porin Por that prevents the phagosome from fusing with lyso-somes, resulting in the survival—and proliferation—of phagocytosed gonococci in granulocytes. The lipo-oligosaccharide (LOS) in the outer membrane is responsible for resistance to complement (serum resistance) as well as for the inflammatory tissue reaction in a manner analogous to the more complexly structured LPS of enterobacteria. Gonococci can capture iron from the siderophilic proteins lactofer-rin and transferrin, accumulating it inside the bacterial cells to facilitate their rapid proliferation. An IgA1 protease produced by the gonococci hydrolyzes secretory antibodies in the mucosal secretions. The pronounced antigen variability of the attachment pili (p. 14) and the Opa protein make it possible for gonococci to thwart specific immune defense mechanisms repeatedly.

— Neisseria gonorrhoeae and Neisseria meningitidis

— Neisseria gonorrhoeae and Neisseria meningitidis

Neisseria Meningitidis And Gonorrhea
a N. gonorrheae: gram staining of a preparation of urethral secretion: coffee-bean-shaped di-plococci, grouped within a granulocyte. Clinical diagnosis: gonorrhea. b N. meningitidis: gram staining of a preparation of cerebrospinal fluid sediment. Clinical diagnosis: acute purulent meningitis.

Was this article helpful?

0 0
Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

Get My Free Ebook

Post a comment