Chapter 137. Gonococcal Infections (Part 7)

Gonococcal Infections in HIV-Infected PersonsThe association between gonorrhea and the acquisition of HIV has been demonstrated in several well-controlled studies, mainly in Kenya and Zaire. The nonulcerative STIs enhance the transmission of HIV by three- to fivefold, possibly because of increased viral shedding by persons with urethritis or cervicitis (Chap. 182). HIV has been detected by polymerase chain reaction (PCR) more commonly in ejaculates from HIV-positive men with gonococcal urethritis than in those from HIV-positive men with nongonococcal urethritis. PCR positivity diminishes twofold after appropriate therapy for urethritis. Not only does gonorrhea enhance the transmission of HIV; it may...
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Chapter 137. Gonococcal Infections (Part 7) Chapter 137. Gonococcal Infections (Part 7) Gonococcal Infections in HIV-Infected Persons The association between gonorrhea and the acquisition of HIV has beendemonstrated in several well-controlled studies, mainly in Kenya and Zaire. Thenonulcerative STIs enhance the transmission of HIV by three- to fivefold, possiblybecause of increased viral shedding by persons with urethritis or cervicitis (Chap.182). HIV has been detected by polymerase chain reaction (PCR) more commonlyin ejaculates from HIV-positive men with gonococcal urethritis than in those fromHIV-positive men with nongonococcal urethritis. PCR positivity diminishestwofold after appropriate therapy for urethritis. Not only does gonorrhea enhancethe transmission of HIV; it may also increase the individuals risk for acquisitionof HIV. A proposed mechanism is the significantly greater number of CD4+ Tlymphocytes and dendritic cells that can be infected by HIV in endocervicalsecretions of women with nonulcerative STIs than in those of women withulcerative STIs. Laboratory Diagnosis A rapid diagnosis of gonococcal infection in men may be obtained byGrams staining of urethral exudates (Fig. 137-1). The detection of gram-negativeintracellular monococci and diplococci is usually highly specific and sensitive indiagnosing gonococcal urethritis in symptomatic males but is only ~50% sensitivein diagnosing gonococcal cervicitis. Samples should be collected with Dacron orrayon swabs. Part of the sample should be inoculated onto a plate of modifiedThayer-Martin or other gonococcal selective medium for culture. It is important toprocess all samples immediately because gonococci do not tolerate drying. Ifplates cannot be incubated immediately, they can be held safely for several hoursat room temperature in candle extinction jars prior to incubation. If processing isto occur within 6 h, transport of specimens may be facilitated by the use ofnonnutritive swab transport systems such as Stuart or Amies medium. For longerholding periods (e.g., when specimens for culture are to be mailed), culture mediawith self-contained CO2-generating systems (such as the JEMBEC or Gono-Paksystems) may be used. Specimens should also be obtained for the diagnosis ofchlamydial infection. PMNs are often seen in the endocervix on a Grams stain, and anabnormally increased number (≥30 PMNs per field in five 1000x oil-immersionmicroscopic fields) establishes the presence of an inflammatory discharge.Unfortunately, the presence or absence of gram-negative intracellular monococcior diplococci in cervical smears does not accurately predict which patients havegonorrhea, and the diagnosis in this setting should be made by culture or anothersuitable nonculture diagnostic method. The sensitivity of a single endocervicalculture is ~80–90%. If a history of rectal sex is elicited, a rectal wall swab(uncontaminated with feces) should be cultured. A presumptive diagnosis ofgonorrhea cannot be made on the basis of gram-negative diplococci in smearsfrom the pharynx, where other Neisseria species are components of the normalflora. Nucleic acid probe tests are sometimes substituted for culture for the directdetection of N. gonorrhoeae in urogenital specimens. A common assay employs anonisotopic chemiluminescent DNA probe that hybridizes specifically withgonococcal 16S ribosomal RNA; this assay is as sensitive as conventional culturetechniques. A disadvantage of non-culture-based assays is that N. gonorrhoeaecannot be grown from the transport systems. Thus a culture-confirmatory test andformal antimicrobial susceptibility testing, if needed, cannot be performed.Nucleic acid amplification tests (NAATs), including Roche Amplicor, Gen-ProbeAPTIMA Combo2 (which also detects Chlamydia), and BD ProbeTec ET, offer anadvantage: urine samples can be tested with a sensitivity similar to that obtainedwhen urethral or cervical swab samples are assessed by culture and other non-NAATs. Because of the legal implications, the preferred method for the diagnosis ofgonococcal infection in children is a standardized culture. Two positive NAATs,each targeting a different nucleic acid sequence, may be substituted for culture ofthe cervix or the urethra as legal evidence of infection; however, cervicalspecimens are not recommended for prepubertal girls. Nonculture tests forgonococcal infection have not been approved by the U.S. Food and DrugAdministration for use with specimens obtained from the pharynx and rectum ofinfected children. Cultures should be obtained from the pharynx and anus of bothgirls and boys, the vagina of girls, and the urethra of boys. For boys with a urethraldischarge, a meatal specimen of the discharge ...