Do women need screening for extragenital gonococcal and chlamydial infections?

Screening for rectal and pharyngeal infection due to Neisseria gonorrhoeae (GC) and Chlamydia trachomatis (CT) is crucial for sexually transmitted disease (STD) control in men who have sex with men (MSM). Extragenital infections account for most GC and CT cases among MSM and are almost always asymptomatic. Women who have receptive anal and oral sex with men can acquire extragenital infection just as MSM can, which raises the question of whether we should allocate public health resources to detecting extragenital infections in women. The report from Trebach and colleagues in this issue moves us closer to answering that question. The investigators studied the clinical epidemiology of extragenitalGC and CT infection among women, MSM, and men who have sex with women only in 2 public STD clinics in Baltimore, Maryland. The clinics implemented pharyngeal screening for all patients who reported exposure through oral sex and implemented rectal screening for all patients who reported receptive penile-anal sex, oral-anal sex, or shared sex toys in the preceding 3 months. The report focuses on patients with isolated extragenital infections, that is, rectal and pharyngeal infections without concurrent genital infection. This is the most relevant outcome for program planning because isolated extragenital infections in women would not be ascertained with standard urogenital testing. For 2 years, the Baltimore STD clinics screened 4402 women forGC or CT infection of the pharynx or rectum. Of these, 57 (approximately 2%) had isolated extragenital CTand 50 (approximately 1%) had isolated extragenitalGC. These infections accounted for 14% of the 412 totalCTand 30% of the 165 totalGC infections inwomen. During the same period, the clinics tested 769MSM, inwhom extragenital infections were substantially more common compared with women. Rectal CTwas the most common extragenital infection in women, and the prevalence of rectal CT was less disparate between women and MSM (9% vs. 14%) compared with rectal and pharyngeal GC. These results, taken together with previous studies summarized in a table in the article, indicate that 10% to 25% of all CT and 20% to 40% of all GC cases in women are missed with standard cervicovaginal or urine screening. The study by Trebach and colleagues enhances the literature on extragenital infections in women because it compares both pharyngeal and rectal infections due to both CT and GC in both women and MSM. Many previous studies on this topic did not directly compare infections in women and MSM, did not determine which extragenital infections were isolated, or limited testing to 1 pathogen or 1 anatomical site. With the addition of this article and 2 others recently published, the compendium of literature clearly demonstrates a few points. First, women contract extragenital GC and CT infections. Although investigators have raised the possibility of false positives or cross-contamination, several studies have found rectal and pharyngeal infections in women who did not have infection at another anatomical site, including what seems to be the earliest report of extragenital gonorrhea in women. Second, nongenital infections in women, particularly rectal chlamydia, are not rare. Although they are much less prevalent in women than MSM, they are sufficiently frequent to raise the question of whether routine screening is indicated. Third, systematic efforts to screen women for extragenital infection increase the detection of GC and CT. However, the mere presence of extragenital infection is not what impacts prevention strategies or clinical management. Rather, the key questions are what clinical harm women's extragenital infections cause, whether screening averts that morbidity, and whether the averted morbidity is worth the cost. In addition, how important are extragenital infections for sustained transmission at the population level?