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In the age of AIDS, attention has tended to focus on that lethal and feared sexually transmitted disease. But for those caring for adolescents, infection by these two bacterial pathogens is still a daily and serious concern. Once they establish a foothold, the way to serious sequelae, including HIV infection, is open.

With the highest rate of sexually transmitted diseases (STDs) in the developed world, the United States is in the throes of a "hidden epidemic," according to a recent report from the Institute of Medicine.¹ In addition to the high human cost to the victims of these diseases and their families, the authors of the report estimate that the financial burden of this epidemic to US taxpayers is at least $10 billion per year - not including the costs of HIV infection. In 1995, of the 10 most frequently reported notifiable diseases, five were STDs, and these accounted for 87% of cases among the top 10 reportables.²

The epidemic comprises a variety of diseases and is the result of many factors: (1) changing sexual mores and patterns; (2) emergence and spread of viral diseases such as herpes, human papillomavirus (HPV), and HIV infection; (3) poor access to clinical health-care services among high-risk populations; (4) inadequate screening and public educational efforts; and (5) lack of a national program focusing on the STD problem. But one factor is common to all STDs and their complications: they are preventable. Yet, regrettably, public expenditures on prevention of STDs amount to only $1 for every $43 spent on treatment and other costs.¹

The disparity between preventive efforts and costs incurred by preventable disease is nowhere more evident than in adolescent medicine. Of the 12 million STD cases occurring in the US every year, 3 million are estimated to occur in teenagers,³ perhaps the most underserved of all population groups in the health-care system. Among those 3 million cases, significantly more than half are in girls and young women, who are more likely to acquire STDs from male partners than to transmit them. They are also more likely than boys and men to suffer long-term and severe consequences - pelvic inflammatory disease, cervical cancer, ectopic pregnancy, and infertility. In addition, unlike their male partners, they are able to transmit infection or its complications to offspring if, as is all too common, they compound STD infection with pregnancy.

To those of us engaged in adolescent gynecology - pediatricians, obstetrician-gynecologists, family physicians, adolescent medicine specialists, and others who provide care for adolescent girls and women - "hidden" is perhaps a misnomer for an epidemic we have been facing as front-line shock troops for some time. We welcome the Institute of Medicine's call for additional resources to confront this problem because it's obvious we can't win this battle alone. However, as primary providers of health services to adolescents, we are still in the best position to help prevent as well as manage these infections and their consequences.

In this article, the first in a series on STDs in adolescents, I will address the two most common bacterial STDs in the US: chlamydial infection and gonorrhea. These two infections are similar not only in many of their signs and symptoms but also in their frequent lack of them. They share other characteristics as well: both are not only preventable but readily curable - when found early; both can lead to serious consequences for young women if not diagnosed and treated appropriately; and, increasingly, both are more prevalent among teenagers than among any other age group.

Why are teens at high risk?
Compared with women of other age groups, adolescents exhibit the highest risk not only for chlamydial infection and gonorrhea but also for syphilis and HPV infection.⁴ While the teen years were never risk free, the emergence of adolescent age itself as a risk factor for STDs may be traced to the changes in teen sexual behavior that began with the so-called sexual revolution of the 1960s and continue today. The latest report from the CDC's Youth Risk Behavior Surveillance System (YRBSS) reveals that in 1995, nationwide, more than half (52.1%) of all high school girls were sexually experienced (Table 1).5 More specifically, the YRBSS data show that 66% of 12th-grade girls had had intercourse at least once and that 20.8% had had more than four sex partners. The same report indicates that 32.1% of 9th-grade girls had already had sexual intercourse and that 7.7% had their first experience before age 13.

Obviously, more and earlier sexual encounters create more opportunity for exposure to STDs. But, as several authors have pointed out, the fact of sexual experience in teens does not necessarily put them at higher risk for consequences such as STDs or unwanted pregnancy. In fact, European adolescents have similar levels of sexual activity and debut but much lower rates of both pregnancy and STDs.^6,7 That is true for the general populations of these countries as well. In Sweden, the reported rate of gonorrhea is about 2% of the US rate; in Canada it is about 12% of the US rate.¹

What makes US teens—and young adults—different is their high frequency of unprotected intercourse. For sexually active adolescents, effective condom use is the best if not the sole hope for avoiding exposure to STDs. Even though there is evidence that teen condom use has increased somewhat over the past decade (Table 2)^5,8—most likely as a result of fear of HIV infection - it is still sporadic and often poorly or incorrectly managed. According to the YRBSS report, only 48.6% of high-school girls could report condom use during their most recent sexual encounter.⁵ Another author notes that most teens are sexually active for up to a year before starting to use any kind of protection.⁹

Why would a young girl or woman risk her health, future fertility, and even her life by failing to apply a method that is easy to use, readily available, and highly effective? Here are some of the reasons:

(1) Ignorance of consequences. Unlike parents in countries where STD rates are much lower, American parents tend not to discuss the specifics of sexual behavior with their children. A 1995 survey showed that only about 11% of US teens get most of their information about STDs from parents and other family members (Figure 1).¹⁰ As a result, teens often get their sexual directions - and misdirections - from friends. Television is another prime source, and not a good one: a recent study found that of every 25 instances of sexual encounters portrayed on prime-time television, only one showed protective behavior.¹¹ Of course, much more reliable information is available from sex education programs in the public schools. However, despite existence of sex education in many schools and availability of condoms in some, such programs are lacking or poorly presented in many parts of the country, particularly the inner cities.

(2) Poor access to health care. Health care providers should be a main source of good sexual information, including condom use, for teens. But adolescents typically make their first visit for gynecologic care when they already have a sex-related problem: disease or pregnancy. About 20% of those 15- to 19-year olds who might have consulted a doctor earlier are uninsured. Even those who have insurance are likely to be covered only by Medicaid or plans that do not provide payment for preventive care.¹

(3) No choice. Adolescent girls, particularly younger ones, may be victims of rape or sexual abuse.

(4) Power imbalance. A woman, particularly a young and inexperienced one, cannot force her male partner to use a condom. Negotiating skills are often needed, and these need to be learned

(5) Circumstances. At the precise moment when she needs one, a girl or her partner may not have a condom, the money to buy one, or a place to buy one.

(6) Low self-esteem. Many studies have traced the origins of high-risk behavior such as unprotected intercourse in teens to a poor sense of self-worth or even a desire to punish themselves or their families. At the other end of the scale are teens who feel their youth and vigor or "street smarts" make them invulnerable to harm or that the warnings of adults aren't to be taken seriously.

(7) Impaired judgment. Use of alcohol, marijuana, and crack cocaine - highly associated with risky behaviors such as having sex with multiple partners or with high-risk partners - makes a rational decision about condom use much less likely. The YRBSS report shows that in 1995 49.9% of high-school girls were currently using alcohol and that 28.6% admitted to periodic heavy drinking. About 22% were currently using marijuana and 5% had used cocaine.⁵

Diagnosis. Culture of endocervical cells is still considered the gold standard for identification of C trachomatis, but culture is relatively expensive and requires careful handling and transport of specimens. In the near future, nucleic acid amplification methods, such as polymerase chain reaction (PCR) and ligase chain reaction (LCR) tests, or transcription-mediated amplification (TMA) tests may replace culture as the new gold standard. These tests will be easier for patients because they can be performed on first-catch urine samples rather than cervical specimens. They also promise results equal or superior to culture in sensitivity and specificity.^17-20

In the meantime, a variety of other nonculture tests are now commercially available and are accepted by the CDC as alternatives to culture provided their limitations are understood. They are less specific than culture tests and, particularly in lower-prevalence areas, may produce false-positive results. Nevertheless, because they are cheaper, easier to use, and reasonably accurate, these tests have an important role in aggressive preventive strategies.

Commercial nonculture tests include the following:

(1) Direct fluorescent antibody (DFA) tests. These tests work by adding fluorescent monoclonal antibodies to a slide containing endocervical material. Antibody binds to chlamydial elementary bodies that can then be identified by fluorescence microscopy. Total processing time is 30 to 40 minutes, but processing must be done by an experienced professional laboratory

(2) Enzyme immunoassay (EIA) tests. In this type of test, monoclonal or polyclonal antibody labeled with a color-signaling enzyme attaches to chlamydial antigen; the result is analyzed with a spectrophotometer. Lab processing is required for these tests as well.

(3) Nucleic acid hybridization tests (DNA probe). This technique employs a chemiluminescent-labeled probe complementary to a particular sequence of chlamydial ribosomal RNA (rRNA). The probe hybridizes with rRNA present in the specimen, and the result is detected with a luminometer. Lab processing is required.

(4) Rapid (stat) tests. These test kits, packaged as single units, operate much like EIA tests in using antibodies to detect antigens of chlamydial species. They may be somewhat less sensitive and specific than tests performed by professional laboratories, but they require less equipment and can be done in the office.

Sensitivities of nonculture tests, measured against culture, must exceed 70% to be adequate for screening, according to the CDC, and most appear to meet this standard.13 Isolation of C trachomatis by culture is diagnostic. A positive result from a nonculture test in an adolescent, particularly if she is from a high-prevalence population, is not considered diagnostic but is usually reason enough for presumptive treatment, since side effects from the antibiotics used are uncommon and mild. The CDC recommends using culture or a second, different nonculture test for verification of chlamydial infection when a false-positive result may have adverse social or psychological consequences or when the patient is from a low-prevalence population.

Even in patients treated presumptively, the CDC recommends testing and verification to ensure appropriate medical care should symptoms persist. Verification also facilitates counseling, provides a basis for partner notification, and enhances compliance.

Treatment.^13,21 Prompt treatment of identified or presumed chlamydial infection in adolescent girls and women is imperative not only to relieve any cervical and urethral symptoms they may have but also to prevent transmission to partners and consequent reinfection. Even more important is eradicating the organism before it has a chance to ascend into the upper reproductive tract, where it has the potential to cause pelvic inflammatory disease and other serious problems.

The CDC's recommendations for uncomplicated endocervical, urethral, or rectal chlamydial infections in nonpregnant girls and women were updated in 1993 and no longer include tetracycline. The preferred regimens now are:

Doxycycline, 100 mg orally, twice a day for 7 days
or
Azithromycin, 1 g orally in a single dose.

Of these two options, the CDC leans toward azithromycin for use in adolescents, since the single-dose treatment can be provided during the patient's visit, eliminating problems of compliance. Results of a recent study from Sweden support this logic, though azithromycin does carry a higher price tag (approximately $30/dose vs. $2 for doxycycline).²² As alternatives for adolescents, the CDC lists these additional options:

Erythromycin base, 500 mg orally four times a day for 7 days
or
Erythromycin ethylsuccinate, 800 mg orally four times a day for 7 days.

The CDC guidelines also mention sulfisoxazole, 500 mg orally, four times daily for 10 days, as a possible though less effective regimen. Ofloxacin, 300 mg orally twice daily for 7 days, is an option for adults but not for pregnant women or adolescents under age 17 because evidence from animal studies suggests it may impair development of cartilage. For pregnant adolescents, doxycycline and azithromycin are also contraindicated, but either of the erythromycin regimens can be given. Amoxicillin, 500 mg orally three times daily for 7 to 10 days, is suggested for pregnant girls and women who can't tolerate erythromycin.

Sequelae. Pelvic inflammatory disease (PID) is the most common serious acute illness stemming from chlamydial infection. It can occur in girls and young women who have never exhibited cervical or urethral symptoms, as can lower abdominal pain and menstrual irregularities. PID can be caused by other organisms or be multifactorial, but C trachomatis has been found in 5% to 50% of those with a complaint of PID. Annually, PID accounts for some 2.5 million office visits, 275,000 hospitalizations, and 100,000 surgical procedures, according to the CDC.¹³ Even when treated, PID can lead to infertility, chronic pelvic pain, or ectopic pregnancy, but the dangers of these consequences are compounded by nontreatment - a result of the often-silent nature of chlamydial infection. One review estimates one fourth of young women will have long-standing sequelae from PID.²³

Endometritis, salpingitis, bartholinitis, and pelvic peritonitis are other manifestations. Chlamydial salpingitis can progress to perihepatitis (Fitz-Hugh-Curtis syndrome), with pain caused by adhesions strung between the liver and the peritoneum. Reiter's syndrome, with arthritis-like symptoms, is more likely to be seen in infected men but can occur in young women. Chronic conjunctivitis should also be part of the differential diagnosis of chlamydial infection in young women. Chlamydial conjunctivitis and pneumonia are concerns for offspring of infected mothers.

Ulcerative STDs like syphilis, herpes, and chancroid have more often been linked as cofactors to HIV infection, but HIV shares with C trachomatis a predilection for cervical ectopy. One recent analysis suggests chlamydial infection may increase HIV susceptibility as much as fivefold.²⁴ Other studies have shown that HIV infectivity decreases with treatment of concurrent STDs.²⁵ This possibility makes the case for early diagnosis and treatment of chlamydial infection even more compelling.

Follow-up.¹³ Treatment failures are uncommon with the CDC's recommended regimens and even with earlier regimens based on tetracycline. For that reason, the CDC does not recommend immediate, routine test-of-cure visits but suggests retesting previously infected women some weeks to months after therapy. That should be particularly true with adolescent patients. For this group, previous infection can be considered a risk factor for future reinfection. A British study of adolescents found a 39% rate of reinfection 2 years after treatment.²⁶

Clearly, the surest way to avoid reinfection and spread of infection is to identify all sexual contacts and see that they are treated. Adolescents' reluctance to name partners, and the limited resources available for contact tracing even when they do, make this a daunting task. One study of contact tracing in an urban non-STD clinic showed that only about 20% ended up being treated.²⁷ Another identified age under 15 as the strongest independent predictor of reinfection by C trachomatis.²⁸ As compared with women over 30, the risk of this group was eightfold, and the risk for 15- to 19-year-olds was fivefold. Difficult as it may be, it's vital to make the effort to see that partners of such young women are identified and treated.

Gonorrhea: down but not out
Neisseria gonorrhoeae, like Chlamydia trachomatis, is an intracellular bacterium that invades the female body by way of the vaginal canal but is much more damaging when it ascends to the upper reproductive tract and pelvic cavity. Until chlamydial infection began to be tracked nationally, gonorrhea was the most frequently reported STD in the US, reaching recorded levels of more than a million cases per year in the late 1970s, with actual cases estimated to be at least three to four times that number.¹² Gonorrhea numbers began to decline in the mid-1980s and continued to decline by about 8% per year until 1993, when they leveled off somewhat.

Even so, based on the nearly 400,000 cases reported in 1995, the CDC estimates actual cases still to be occurring at a rate of 1 million per year in the US (Table 3). Though one would expect about half of these cases to be in women, rates for female adolescents actually have consistently been higher than for their male age mates, and the rate for 10- to 14-year-old girls rose 51.2% between 1981 and 1991 while it was declining for most other groups.²⁹ Moreover, the overall decline in gonorrhea has been less sharp for women under 20; between 1993 and 1994, there was even a slight increase in the rate for 10- to 19-year-olds,²⁹ though the rate resumed its decline in 1995. Rates for minority adolescents remain exceptionally high, especially in inner-city populations.

The message is that even though gonorrhea is a disease in overall decline in the US, we cannot assume that this trend will continue. The disease is still highly prevalent, especially in adolescent girls and women. The modest improvements in condom use and safer sex practices in the 1990s following publicity about AIDS has probably helped keep gonorrhea rates in check in this group. The fact that the disease is somewhat less occult than chlamydial infection in women - and much less so in their male partners - probably has also helped. After all, gonorrhea, unlike Chlamydia, is a word most teens at least recognize and fear.

Screening. As with chlamydial infection, primary prevention of gonorrhea in adolescents requires screening of all sexually active adolescents and young adults at least annually, following a careful sexual history, whether or not they have symptoms.²¹ Also, as with chlamydial infection, suspicion should be highest in girls who have had multiple sex partners, recent new partners, history or current use of drugs, poor or nonuse of condoms, and any suggestion of physical or sexual abuse. The CDC also recommends blood test screening for syphilis when gonorrhea is first detected.

Signs and symptoms. In men, gonorrheal infections usually cause symptoms within a week or two of exposure, impelling them to seek treatment soon enough to prevent serious sequelae. Since the transmission rate from men to women is virtually 100% (it is only about 25% in the opposite direction), infection in a partner after unprotected intercourse is reason enough for a young woman to be evaluated, whether or not she has symptoms. If symptomatic, she will have a presentation very much like that of chlamydial disease, with vaginal or urinary symptoms 2 to 7 days after intercourse.¹⁶ Yellowish green mucopurulent endocervical discharge is the classic sign, but dysfunctional uterine bleeding, dysuria, and dyspareunia are common. Pharyngitis or proctitis may also be part of the clinical picture if there has been oral or anal sex.

Diagnosis.¹⁶ For gonorrhea, culture is still both the gold standard and the common method of identification. Self-contained culture packages are commercially available. Throat or rectal cultures should be taken if there has been oral or anal sex. (These cultures are not yet recommended by the CDC for chlamydial evaluation but are probably not a bad idea.) Gram staining of cervical secretions will often visualize neisserial diplococci, but in women it is not sensitive enough to be used alone for diagnosis.

Rapid techniques are also commercially available for gonorrhea detection and can be useful in high-prevalence populations, though subject to the problem of false-positives in low-prevalence populations. As with chlamydial detection, PCR and LCR urine tests may make diagnosis easier and less invasive in the near future.

Treatment. Antimicrobial therapies for gonorrhea have been in use virtually since their discovery, and the unsurprising result is the widespread appearance of gonococcal strains resistant to penicillin, ampicillin, and tetracycline. Fortunately, other antibiotics are available and are effective against gonorrhea, but since N gonorrhoeae seems to be an adaptable organism, resistance will always be a concern. Resistance to quinolones is already being reported.³⁰

Four single-dose regimens are currently the first-line recommendations of the CDC for treatment of uncomplicated anal and genital gonococcal infections²¹:

Ceftriaxone, 125 mg IM;
Cefixime, 400 mg orally;
Ciprofloxacin, 500 mg orally;
or
Ofloxacin, 400 mg orally.

However, since ciprofloxacin and ofloxacin are quinolones and therefore contraindicated for patients under 17 as well as pregnant and nursing mothers, the choice narrows to IM ceftriaxone or oral cefixime for most adolescents. Of these two treatments, the CDC prefers ceftriaxone when pharyngeal infection is also suspected.

Because coinfection by C trachomatis is common, the CDC recommends adolescents being treated for gonorrhea be treated presumptively for chlamydial infection as well. Because of costs, the 1993 guidelines list only doxycycline (100 mg orally twice daily for 7 days) for this cotherapy, but if suspicion of chlamydial involvement is high and confidence in compliance low, azithromycin might be considered instead, despite its higher cost.

As additional alternatives for gonorrheal infection in adolescents, the CDC also lists the following single-dose IM treatments: spectinomycin, 2 g; ceftizoxime or cefotaxime, 500 mg; cefotetan; or cefoxitin, 2 g. Two single-dose oral cephalosporins are also mentioned -cefuroxime axetil, 1 g, and cefpodoxime proxetil, 200 mg - but are said to be less active against gonococci than cefixime.

Sequelae. Left untreated, gonorrhea is likely to lead to acute PID, with all the associated problems mentioned earlier for ascending chlamydial infection: chronic pelvic pain, tubal scarring with resultant infertility, and life-threatening ectopic pregnancy. Conjunctivitis and perihepatitis may also be seen, and offspring of infected mothers are susceptible to gonococcal ophthalmia neonatorum, a serious condition that can result in blindness

Systemic spread has been recognized under the heading of disseminated gonococcal infection (DGI), a result of gonococcal bacteremia. Manifestations include petechial or pustular acral skin lesions, asymmetrical arthralgias, tenosynovitis, and septic arthritis - occasionally complicated by hepatitis and, rarely, by endocarditis or meningitis. Strains of N gonorrhoeae that cause DGI usually do not provide the warning signal of earlier genital symptoms, but fortunately these strains are uncommon in the US.

Finally, some studies have suggested that gonorrhea, like chlamydial infection, may be a cofactor facilitating transmission of or susceptibility to HIV infection.^31,32

Follow-up. Women treated for uncomplicated gonorrhea with any of the recommended regimens do not need to return for a test of cure, according to the CDC.21 However, those whose symptoms persist need to be reevaluated by culture, with any gonococcal isolates tested for antimicrobial susceptibility. As with chlamydial infection, resumption of symptoms more often indicates reinfection than treatment failure. To avoid infecting partners, young women should be instructed to avoid sexual intercourse until therapy is concluded and symptoms are gone.

As with chlamydial infection, follow-up must include the patient's partner or partners. For women with gonorrheal symptoms, the CDC advises evaluation of all sex contacts within 30 days of the onset of symptoms. For asymptomatic women, the inquiry should extend out to 60 days of onset.

Strategies: toward prevention and eradication
High prevalence of preventable and curable diseases such as chlamydial infection and gonorrhea may be a consequence of trends in American life today, but it is neither inevitable nor acceptable. Though their populations and circumstances are not always comparable to ours, various other developed countries have had better success in checking these infections. In any event, the pain and suffering these diseases cause to our young people is reason enough to increase our efforts to prevent and eradicate them. Their possible implication in the spread of a lethal STD like AIDS makes these efforts all the more vital.

In its recent report The Hidden Epidemic: Confronting Sexually Transmitted Disease, the Institute of Medicine has spelled out the problems comprehensively and dramatically (Figure 2). As the authors point out, a key stumbling block to putting together an effective national system to deal with STDs is that "many Americans are reluctant to address sexual health issues in an open way." That is unfortunate, but it underscores that the issues to be addressed are probably as much social, moral, and political as biological and epidemiological.

As the report authors recognize, establishment of an effective national system for STD prevention will take time and require intermediate steps. But as a start, here are 10 steps I think would help, particularly from the standpoint of protecting adolescent girls and women:

(1) Recognizing the impact of STDs on HIV transmission.
(2) Streamlining partner notification and treatment.
(3) Promoting public knowledge and awareness of STD prevention with more balanced media messages.
(4) Sharpening professional skills in dealing with adolescent sexuality and behavior.
(5) Supporting and expanding health behavior research.
(6) Enlisting and promoting support from the private sector - particularly managed care organizations.
(7) Improving school-based and local community sex education programs.
(8) Improving surveillance and reporting systems, particularly at the local level.
(9) Developing effective female-controlled methods for protecting against STDs. And, most important, ensuring access to care.

REFERENCES

1. Committee on Prevention and Control of Sexually Transmitted Diseases, Institute of Medicine; Eng TR, Butler WT (eds): The Hidden Epidemic: Confronting Sexually Transmitted Diseases. National Academy Press, Washington, DC, 1996
2. Centers for Disease Control and Prevention: Ten leading nationally notifiable infectious diseases - U.S. MMWR 1996;45(41):883
3. Division of STD/HIV Prevention, Centers for Disease Control and Prevention: Annual report, 1994. U.S. Department of Health and Human Services, Public Health Service, Atlanta, 1995
4. Schydlower M, Shafer MA: State of the Art Reviews: AIDS and Other Sexually Transmitted Diseases. Philadelphia, Hanley-Belfus, 1990
5. Centers for Disease Control and Prevention: Youth Risk Behavior Surveillance - United States, 1995. MMWR 1996;45(SS-4):16
6. Alan Guttmacher Institute: Teenage Pregnancy in Developed Countries. New Haven, Yale University Press, 1986
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8. Centers for Disease Control and Prevention: Trends in sexual risk behavior among high school students - United States, 1990, 1991, and 1993. MMWR 1995;44:124
9. Vatin M: Barrier and chemical contraceptives, in Rivlin ME, Martin RW (eds): Manual of Clinical Problems in Obstetrics and Gynecology. 4th ed. Boston, Little, Brown and Co., 1990, pp 385- 410
10. American Social Health Association: Teenagers know more than adults about STDs, but knowledge among both groups is low. STD News 1996;3:1
11. Lowry DR, Schidlet JA: Prime time TV portrayals of sex, "safe sex," and AIDS: A longitudinal analysis. Journalism Q 1993;70:628
12. Centers for Disease Control and Prevention: Summary of notifiable diseases, United States, 1995. MMWR 1995;44(53):3
13. Centers for Disease Control and Prevention: Recommendations for the prevention and management of Chlamydia trachomatis infections, 1993. MMWR 1993;42(RR-12):1
14. McGregor JA: Chlamydial infection in women. Obstet Gynecol North Am 1989;16:565
15. Finelli L, Nakashima AK, Hillis S, et al: Selective screening versus presumptive treatment criteria for identification of women with chlamydial infection in public clinics - New Jersey. Am J Obstet Gynecol 1996;174(5):1527
16. Strasberger VC, Brown RT: Adolescent Medicine: A Practical Guide. Boston, Little, Brown and Co., 1991, pp 265 - 325
17. Schachter J, Moncada J, Whidden R, et al: Noninvasive tests for diagnosis of Chlamydia trachomatis infection. J Infect Dis 1995;172(5):1411
18. Buimer M, Vandoornum GJJ, Ching S, et al: Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by ligase-chain reaction-based assays with clinical specimens from various sites - implications for diagnostic testing and screening. J Clin Microbiol 1996;34(10):2395
19. Toye B, Peeling RW, Jessamine P, et al: Diagnosis of Chlamydia trachomatis infections in asymptomatic men and women by PCR assay. J Clin Microbiol 1996;34(6):1396
20. Quinn TC, Welsh L, Lentz A, et al: Diagnosis by Amplicor PCR of Chlamydia trachomatis infection in urine samples from women and men attending sexually transmitted disease clinics. J Clin Microbiol 1996;34(6);1401
21. Centers for Disease Control and Prevention: 1993 Sexually Transmitted Diseases Treatment Guidelines. MMWR 1993;42(RR-14):50
22. Genc M, Mardh PA: Cost-effectiveness analysis of screening and treatment for Chlamydia trachomatis infection in asymptomatic women. Ann Intern Med 1996;124(1,Part 1):1
23. Shafer MA, Sweet RL: Pelvic inflammatory disease in adolescent females. Pediatr Clin North Am 1989;36:513
24. Boily MC, Anderson RM: Human immunodeficiency virus transmission and the role of other sexually transmitted diseases: Measures of association and study design. Sex Transm Dis 1996;23:312
25. STDs as cofactors for the acquisition of HIV infection. Contraception Rep 1996;3(2):9
26. Jones RB: Treatment of Chlamydia trachomatis infections in the urogenital tract, in Bowie WR, Caldwell HD, Jones RP, et al (eds): Chlamydial Infections: Proceedings of the Seventh International Symposium on Human Chlamydial Infections. Cambridge, Cambridge University Press, 1990, pp 509 - 518
27. Oh MK, Boker JR, Genuardi FJ, et al: Sexual contact tracing in adolescent chlamydial and gonococcal cervicitis cases. J Adolesc Health 1996;18(1):4
28. Hillis SD, Nakashima A, Marchbanks PA, et al: Risk factors for recurrent Chlamydia trachomatis infections in women. Am J Obstet Gynecol 1994;170(3):801
29. Webster LA, Berman SM, Greenspan JR: Surveillance for gonorrhea and primary and secondary syphilis among adolescents, United States - 1981 -1991. MMWR 1993;42(SS-3):1
30. Centers for Disease Control and Prevention:Fluoroquinolone resistance in Neisseria gonorrhoeae - Colorado and Washington, 1995. MMWR 1995;44(41):761
31. Cates W: The epidemiology and control of sexually transmitted diseases in adolescents in Schydlower M, Shafer MA (eds): AIDS and Other Sexually Transmitted Diseases. Philadelphia, Hanley and Belfus, 1990, pp 409 - 427
32. Wasserheit JN: Epidemiological synergy. Interrelationships between human immunodeficiency virus infection and other sexually transmitted diseases. Sex Trans Dis 1992;19:61

Dr. Goldfarb is professor of obstetrics and gynecology, Thomas Jefferson School of Medicine, and former executive director of NASPAG.

Copyright © 1999 Medical Economics Company. Reprinted from Contemporary Adolescent Gynecology Magazine.