GONOCOCCAL INFECTION: AN OVERVIEW
Gonorrhea remains the second most commonly reported communicable disease in the United States, with an estimated incidence of 120.9/100,000.1 The gram-negative, nonmotile, non–spore-forming diplococci N gonorrhoeae are seen frequently within phagocytes in the Gram stain of clinical specimens (Figure 3). Humans are the only reservoir for gonococci. The main mode of transmission is through contact with the exudates or secretions from infected mucosal surfaces during sexual acts or vaginal birth and, rarely, from household surfaces in prepubertal children.2 The incubation period is usually 2 to 7 days.
Figure 3. This photomicrograph depicts the gram-negative bacteria Neisseria gonorrhoeae. (Courtesy of the CDC/Joe Miller.)
Rates of infection are highest among young women 15 to 19 years of age1—such as this patient’s mother. Lower socioeconomic status, unmarried status, sexual activity at a young age, prostitution, injection drug use, and past gonococcal infections are risk factors for gonococcal infection.3,4 Inherited or acquired terminal complement deficiencies predispose patients to disseminated gonococcal infection.5 The rate of congenital gonococcal infection in neonates directly relates to that in the mothers and is highest in adolescent pregnancies. Among pregnant women with gonococcal infection, 13% experience septic abortion, 29% have premature rupture of membranes, and 20% deliver prematurely.6 Neonatal infection occurs via ascending infection, possibly secondary to chorioamnionitis; with ruptured membranes before delivery; or during passage through the birth canal. The most common infection in the neonatal period is gonococcal ophthalmia neonatorum (GON)—as in this patient. Other gonococcal infections in neonates include scalp abscesses, meningitis, and sepsis.
POST-EXPOSURE PROPHYLAXIS FOR GONOCOCCAL INFECTION
A single dose of parenteral ceftriaxone (Drug information on ceftriaxone) is recommended as postexposure prophylaxis to prevent disseminated infection in infants born to mothers with untreated gonorrhea. Prophylaxis for GON is required by law for all infants within 1 hour after birth. One percent silver nitrate(Drug information on silver nitrate) solution, 1% tetracycline(Drug information on tetracycline) ointment, and 0.5% erythromycin(Drug information on erythromycin) ointment are considered equally effective—but not completely protective. A conjunctival infection develops in up to 10% of exposed infants who receive silver nitrate prophylaxis, compared with 2% to 48% of exposed infants who do not receive ocular prophylaxis.6 Erythromycin ointment is currently used in most hospitals.
GONOCOCCAL OPHTHALMIA NEONATORUM
Clinical characteristics. GON typically develops 2 to 5 days after birth; however, it may present as late as 2 to 3 weeks after delivery because of partial protection from prophylactic eyedrops. Hyperacute conjunctivitis with copious purulent discharge and significant lid swelling is characteristic. Infection is usually bilateral and associated with significant chemosis. GON is considered to be a medical emergency because corneal ulceration, perforation of the globe, and panophthalmitis with loss of vision can occur if treatment is delayed.
Diagnosis. The differential diagnosis for neonatal conjunctivitis includes chemical conjunctivitis and conjunctivitis caused by other organisms (such as C trachomatis; herpes simplex virus; Streptococcus pneumoniae; nontypeable Haemophilus influenzae; Staphylococcus aureus; and, rarely, enteric organisms, such as Klebsiella pneumoniae and enterococci).7 Chemical conjunctivitis usually appears within 6 to 24 hours of administration of prophylactic eyedrops and resolves within 24 to 48 hours; it is most commonly associated with silver nitrate drops. GON may be distinguished from other types of conjunctivitis by its severity and rapid progression, although there is some clinical overlap. Chlamydia conjunctivitis, for instance, has a longer incubation and manifests between 5 and 14 days after birth.
Order a Gram stain immediately for a neonate with purulent conjunctivitis. If risk factors for gonococcal infection are present, start therapy for GON while awaiting culture results. Testing for Chlamydia and other bacteria is also indicated. Giemsa staining that is positive for Chlamydia does not rule out concomitant gonorrheal infection. Nucleic acid amplification tests are as sensitive as cultures, have a high specificity, and can be used for screening.8 Culture of fluid from the infected eye remains the gold standard for GON diagnosis. Cultures of blood and CSF are also recommended when systemic gonococcal infection is suspected or proved in a neonate,2,6 although some experts maintain that evaluation for meningitis is unnecessary in a well-appearing infant.
Treatment. Neonates with suspected GON require hospitalization and an ophthalmology consultation. A single parenteral dose of a third-generation cephalosporin should be given. Hourly ocular lavage with saline decreases the organism load that has access to the cornea. The addition of erythromycin ointment is helpful in treating possible Chlamydia conjunctivitis.
When Chlamydia is detected, a 14- to 21-day course of oral erythromycin is indicated to eradicate the nasopharyngeal carriage of this pathogen and to prevent Chlamydia pneumonia.
Dr Tigchelaar is clinical associate professor of pediatrics and Dr Kannikeswaran is assistant professor of pediatrics in the Carman and Ann Adams Department of Pediatrics, division of emergency medicine, at the Children’s Hospital of Michigan in Detroit. Dr Kamat is professor of pediatrics at Wayne State University in Detroit. He is also director of the Institute of Medical Education in Detroit and vice chair of education at Children’s Hospital of Michigan.
- Centers for Disease Control and Prevention. Sexually Transmitted Disease Surveillance 2006. Gonorrhea. Atlanta: US Dept of Health and Human Services; 2007. http://www.cdc.gov/std/stats/gonorrhea.htm. Accessed February 20, 2008.
- American Academy of Pediatrics. Gonococcal infections. In: Pickering LK, Baker CJ, Long SS, eds. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th ed. Elk Grove Village, IL: APA; 2006:301-309.
- Barnes RC, Holmes KK. Epidemiology of gonorrhea: current perspectives. Epidemiol Rev. 1984;6:1-30.
- Brooks GF, Darrow WW, Day JA. Repeated gonorrhea: an analysis of importance and risk factors. J Infect Dis. 1978;137:161-169.
- Ellison RT III, Curd JG, Kohler PF, et al. Underlying complement deficiency in patients with disseminated gonococcal infection. Sex Transm Dis. 1987;14: 201-204.
- Woods CR. Gonococcal infections in neonates and young children. Semin Pediatr Infect Dis. 2005; 16:258-270.
- Di Bartolomeo S, Mirta DH, Janer M, et al. Incidence of Chlamydia trachomatis and other potential pathogens in neonatal conjunctivitis. Int J Infect Dis. 2001;5:139-143.
- Whiley DM, Tapsall JW, Sloots TP. Nucleic acid amplification testing for Neisseria gonorrhoeae: an ongoing challenge. J Mol Diagn. 2006;8:3-15.