A commonly reported infectious disease in the United States, gonorrhea is sexually transmitted and principally affects adolescents and young adults. Infants can be infected by passage through an infected birth canal. Children can acquire the disease through sexual play, molestation, and sexual abuse. The principal manifestation of the uncomplicated infection is a urethral or vaginal discharge; however, localized infections of the fallopian tubes, joints, conjunctiva, pharynx, and anus, as well as disseminated infection, can occur.
PATHOGENESIS AND EPIDEMIOLOGY
The gonococcus is a gram-negative kidney bean–shaped diplococcus, nonmotile and nonencapsulated, and fastidious in its nutritional requirements. It grows best aerobically in carbon dioxide with increased humidity on a medium of chocolate agar with antibiotics (Thayer-Martin medium) that suppress the growth of other microorganisms. Gonococci grow in small colonies that are easily identified; they elaborate indophenoloxidase—the basis for identification by an oxidase test. However, definitive identification (required in more complicated clinical settings and for medicolegal purposes) requires the use of specific fluorescein-conjugated antibody staining or sugar fermentation.
Neisseria gonorrhoeae infects nonciliated columnar and transitional epithelial cells. Attachment to the cells is mediated by pili and the outer-membrane opacity proteins. Within 24 to 48 hours after attachment, the organism synthesizes enzymes to facilitate penetration to submucosal tissues. The host produces a neutrophil response, which results in sloughing of the epithelium, submucosal abscesses, and a purulent exudate. N gonorrhoeae is capable of invading the bloodstream and disseminating to other sites, such as the joints and meninges. Bacteremic spread is also more likely to occur in conjunction with menstruation, which facilitates spread to the upper genital tract (salpingitis). Deficiency of one of the terminal components of the complement system (especially factors 5, 6, 7, or 8) places the patient at increased risk of disseminated, chronic, or recurrent gonococcal disease.
Gonococcal infections are limited to humans, and transmission is almost always sexual (genital, anal, or oral). The US rate of reported gonorrhea cases reached a historic low of 98.1 cases per 100,000 people in 2009. However, the rates of gonorrhea infections have been increasing slightly each year since then, to a rate of 110.7 cases per 100,000 people in 2014 (a total of 350,062 cases were reported to the Centers for Disease Control and Prevention [CDC] in 2014). The increase in gonorrhea has been observed primarily among men. Rates increased among individuals age 20 to 24 years and in older age groups, but decreased among younger age groups. Gonorrhea infections have increased in South and West United States but have decreased in the Northeast and Midwest. Sexual transmission and risk factors for gonococcal infection are further discussed in Chapter 228.
The incubation period of gonorrheal infection is 2 to 7 days. Infection may occur in the newborn period, in prepubertal children, and in sexually active adolescents and adults. The majority of infected males present with ...