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Prevention of Pelvic Inflammatory Disease (PID): Screening for Chlamydia trachomitis and Neisseria gonorrhoeae

Prevention of Pelvic Inflammatory Disease (PID): Screening for Chlamydia trachomitis and Neisseria gonorrhoeae

Clinical Focus

Prevention of Pelvic Inflammatory Disease (PID)

Screening for Chlamydia trachomatis and Neisseria gonorrhoeae

  

Contents:

Clinical Background

Individuals Suitable for Testing

Test Availability

Test Selection

Test Interpretation

References
 

Clinical Background [return to contents]

Pelvic inflammatory disease (PID) is one of the most common complications of sexually transmitted infections in women. It affects various structures of the upper female genital tract, leading to disorders such as endometritis, salpingitis, tubo-ovarian abscess, and pelvic peritonitis.1 In the United States PID affects about 750,000 women each year, causing infertility in about 10% to 15% of affected women.2 It can lead to chronic pelvic pain and is also a major cause of ectopic pregnancy.2 PID presents with a wide clinical spectrum and often goes undetected because signs and symptoms are non-specific; therefore, a low threshold for diagnosis should be maintained.1

PID is often caused by sexually transmitted organisms, most commonly Chlamydia trachomatis and Neisseria gonorrhoeae. Other causative organisms include constituents of vaginal flora, such as anaerobic bacteria, Gardnerella vaginalis, Haemophilus influenzae, enteric gram-negative rods, and Streptococcus agalactiae.2,3 Cytomegalovirus, Mycoplasma hominis, Mycoplasma genitalium, and Ureaplasma urealyticum have also been implicated as causative agents.1-4

Chlamydia and gonorrhea are the 2 most common reportable sexually transmitted infections in the United States.5 Each year an estimated 2.9 million new C trachomatis infections occur among adolescents and adults in the United States6; N gonorrhoeae is responsible for an estimated 820,000 new infections annually.6 These diseases affect both men and women and are often spread unknowingly by asymptomatic individuals. Infection during pregnancy may result in neonatal transmission, leading to complications such as ophthalmia neonatorum and pneumonia.

Cure rates for chlamydial infection are about 97% to 98% with a 7-day, multidose regimen of doxycycline or a single dose of azithromycin.7 N gonorrhoeae also responds well to treatment, although resistance to beta-lactams, fluoroquinolones, and oral cephalosporins can complicate response. Fluoroquinolones are not recommended for treatment of gonorrhea, and oral cephalosporins are no longer recommended as a first-line therapy.8 Because chlamydia is common in patients with gonorrhea, cotreatment should be considered in individuals with diagnosed gonorrheal infection.8 See Centers for Disease Control and Prevention (CDC) guidelines for currently recommended treatment regimens.8

Current guidelines recommend N gonorrhoeae and C trachomatis testing, as well as HIV screening, for all women with PID.1 Conversely, screening for N gonorrhoeae and C trachomatis may also aid in detecting subclinical PID or avoiding progression to PID. Subclinical PID has been reported in >25% of women with gonorrhea or chlamydia9; some studies have indicated that up to 40% of women with untreated chlamydia develop PID.10 Because most people with C trachomatis infection are asymptomatic and are not aware of their infection, screening is important if these infections are to be adequately diagnosed and treated. Chlamydia screening among asymptomatic, sexually active women can decrease the incidence of PID11 and, possibly, the prevalence of chlamydial infection. Screening for cervical C trachomatis infection in asymptomatic women can be cost effective. Screening with a DNA amplification assay, coupled with a single dose of azithromycin in positive patients, was reported to be a cost-effective strategy when the prevalence is 6% or greater.12 Screening high-risk women and treating those infected was found to significantly lower the incidence of PID relative to a control population (9/1009 [0.9%] vs 33/1598 [2.1%], respectively).11 Similarly, an economic evaluation of a school-based sexually transmitted infection program in New Orleans revealed a savings of $1524 for each case of PID prevented.13 Thus, timely detection followed by effective therapy appears to be a cost-effective way of preventing complications and further spread of C trachomatis infection.

Guidelines from the CDC now recommend routine annual chlamydia screening for all sexually active women under 25 years of age and for all women at increased risk.1 Moreover, because repeat infection is common in women with chlamydia, retesting should be considered about 3 to 4 months after treatment.1 Targeted gonorrhea screening among sexually active women at high risk for infection is also recommended (see “Individuals Suitable for Testing” below).14

Individuals Suitable for Testing1,14,15 [return to contents]

Chlamydia

Gonorrhea

Symptomatic individuals Symptomatic individuals

Sex partners of infected individuals
(symptomatic and asymptomatic)

Sex partners of infected individuals
(symptomatic and asymptomatic)
All sexually active women 25 years of age;
women >25 years of age at high risk (see
below)
Women at high risk (see below)
All pregnant women (1st prenatal visit)
Pregnant women ≤25 years of age (3rd trimester)
Pregnant women at high risk (see below)
(3rd trimester)
Pregnant women at high risk (see below)
(1st prenatal visit with retesting in 3rd trimester)

Women at high risk include:

  women and teens attending STI, family

planning, or prenatal clinics

  women with a previously diagnosed STI

  women in high-prevalence settings

  women undergoing elective abortion

  women residing in detention facilities

  women with new or multiple sex partners

  women with inconsistent or incorrect use

of barrier protection

  women being evaluated for infertility

Women at high risk include:

  sexually active women 25 years of age with

2 or more sex partners in the past year

  women with a previously diagnosed STI

  women in high-prevalence settings

  commercial sex workers

  women with a history of repeated episodes

of gonorrhea

  intravenous drug users

 

STI, sexually transmitted infection.

Note: Screening strategy will vary depending on prevalence in the patient population.

Test Availability [return to contents]

Nucleic Acid Amplification Tests

  • Chlamydia trachomatis RNA, TMA: This test directly detects the presence of C trachomatis ribosomal RNA (rRNA). It is based on transcription-mediated amplification (TMA) and is highly sensitive and specific. The test can be performed on either swab or urine specimens from men and women.

  • Chlamydia trachomatis RNA, TMA Alternate Target: This test directly detects the presence of C trachomatis ribosomal RNA (rRNA) using an alternate molecular target than the routine Chlamydia trachomatis RNA, TMA assay. It can be ordered to confirm an initial positive result. It is based on TMA and is highly sensitive and specific. The test can be performed on either swab or urine specimens from men and women.

  • Chlamydia trachomatis DNA, SDA: This test directly detects the presence of C trachomatis DNA. It is based on strand displacement amplification (SDA) and is highly sensitive and specific. The test can be performed on either swab or urine specimens from men and women. The test can also be performed on endocervical specimens submitted in liquid-based Pap test vials.

  • Neisseria gonorrhoeae RNA, TMA Alternate Target: This test directly detects the presence of N gonorrhoeae rRNA using an alternate molecular target than the routine Neisseria gonorrhoeae RNA, TMA assay. It can be ordered to confirm an initial positive result. It is based on TMA and is highly sensitive and specific. The test can be performed on either swab or urine specimens from men and women.

  • Neisseria gonorrhoeae RNA, TMA: This test directly detects the presence of N gonorrhoeae rRNA. It is based on TMA and is highly sensitive and specific. The test can be performed on either swab or urine specimens from men and women.

  • Neisseria gonorrhoeae DNA, SDA: This test directly detects the presence of N gonorrhoeae DNA. It is based on SDA and is both sensitive and specific. The test can be performed on either swab or urine specimens from men and women. The test can also be performed on endocervical specimens submitted in liquid-based Pap test vials.

Non-nucleic Acid Tests

  • Chlamydia trachomatis Antigen, DFA: The direct fluorescence antibody assay (DFA) directly detects the presence of C trachomatis. This test is cleared for conjunctiva specimens. Specimens are incubated with fluorescein-labeled monoclonal antibody and examined microscopically for fluorescence of chlamydial elementary bodies. Specimen quality is assessed by checking for the presence of epithelial columnar cells.

  • Chlamydia trachomatis Antibodies: This immunofluorescence assay detects antibodies (IgM, IgG, and IgA) produced as an immune response to C trachomatis infection.

  • Chlamydia trachomatis Culture: This test detects the presence of C trachomatis. The organism is grown in cell culture and then identified via an immunofluorescence assay with monoclonal antibodies specific for the major outer membrane protein (MOMP), present in all 15 known serovars of C trachomatis but not C pneumoniae or C psittaci.

  • Neisseria gonorrhoeae Culture: This test detects the presence of N gonorrhoeae. Organisms are identified by biochemical characteristics and confirmed by a molecular assay. Culture and susceptibility should be performed in cases of suspected treatment failure.

Test Selection [return to contents]

Chlamydia Screening and Diagnosis

Culture is no longer the standard for diagnosis of C trachomatis infection. With the advent of nucleic acid amplification and detection methods, culture is used infrequently because of higher cost, specimen viability requirements during collection and transport, and slow turnaround time (3–7 days). Culture continues to be the most specific method (~100%), followed closely by nucleic acid amplification assays. The remaining methods range from 97% to 99% specific, depending on the study. The CDC recommends nucleic acid amplification tests for detecting infection of the reproductive tract in both men and women, regardless of symptoms.1

Non-culture tests for C trachomatis are more rapid and standardized and have less stringent specimen handling requirements. Nucleic acid amplification tests such as SDA and TMA are the most sensitive methods for detecting C trachomatis.1 Compared with amplification methods, culture is only 70% to 85% sensitive.16,17 The remaining tests are all less sensitive than culture (sensitivity roughly 70%7–97% that of culture, depending on reagent manufacturer and specimen type).

Chlamydia Test-of-Cure

Routine test-of-cure is not recommended for chlamydia when first-line regimens are used.1 When test-of-cure is indicated, as in the case of chlamydial infection during pregnancy, nucleic acid amplification testing should be performed 3 weeks post-therapy.1 Non-culture detection methods should not be used <3 weeks after treatment is completed.1

Gonorrhea

Nucleic acid amplification testing of endocervical, vaginal, male urethral, or urine specimens can be used to detect of gonorrhea affecting the genitourinary system.1 Culture and antimicrobial susceptibility testing should also be performed when treatment failure is suspected.1

As with chlamydia testing, nucleic acid amplification assays for gonorrhea offer convenience and high sensitivity. The difference in sensitivity between culture and nucleic acid amplification methods is less pronounced than with chlamydia, although inappropriate storage and transport conditions can lessen the sensitivity of culture. SDA has shown specificity similar to that of culture and greater sensitivity).18 TMA also exhibits excellent specificity (99% in swabs and urine) and sensitivity (99% in swabs, 91% in urine).19

Test Interpretation [return to contents]

Positive results are considered evidence of infection. Because of the high specificity of available molecular tests, confirmatory testing is generally not necessary.20 However, in low prevalence populations or in a case where a positive may have severe socio-legal ramifications, testing with an alternate method or target is recommended. Individuals positive for one STI should be tested for others.

Chlamydia

Antibody tests: C trachomatis infection confers little immunity against reinfection, although secretory IgA may provide some protection. A positive IgM antibody result may indicate recent infection with C trachomatis; a negative result, however, does not indicate absence of C trachomatis since IgM antibodies are frequently absent in infected individuals. The presence of IgG indicates active or resolved infection. High IgG titers often point to recent infection, whereas intermediate or low titers may be due to early infection, resolved infection, or cross-reaction with other Chlamydia species. When comparing antibody tests, a 4-fold rise in titer best indicates active infection. Serologic tests are not recommended for chlamydia screening.3

Culture: A positive culture result is highly specific for C trachomatis. A negative result may indicate absence of C trachomatis infection or a false-negative due to lack of organism viability or improper specimen collection.

DFA: A positive DFA result indicates the presence of C trachomatis infection, whereas a negative result implies absence of infection or a false-negative due to lack of assay sensitivity.

RNA, TMA: A positive TMA result is highly indicative of C trachomatis infection, while a negative result is highly indicative of lack of infection. False-positive results may be obtained due to laboratory contamination (rare in an experienced lab) or sampling too soon after cessation of therapy (ie, <3 weeks post-therapy).

DNA, SDA: A positive DNA result is highly indicative of C trachomatis infection. False-positive results may be obtained due to laboratory contamination (rare in an experienced lab) or sampling too soon after cessation of therapy (ie, <3 weeks post-therapy). Negative results are highly specific for lack of C trachomatis infection but may be caused by interfering substances.

Gonorrhea

Culture: A positive culture result is highly specific for N gonorrhoeae. A negative result may indicate absence of infection or a false-negative due to lack of organism viability or improper specimen collection.

DNA, SDA: A positive test result strongly suggests N gonorrhoeae infection. False-positive results may be obtained due to laboratory contamination (rare in an experienced lab) or sampling too soon after cessation of therapy (ie, <3 weeks post-therapy). Negative results are highly specific for absence of N gonorrhoeae infection but may be caused by interfering substances.

RNA, TMA: A positive TMA result is highly indicative of N gonorrhoeae infection, while a negative result is highly indicative of lack of infection. False-positive results may be obtained due to laboratory contamination (rare in an experienced lab) or sampling too soon after cessation of therapy (ie, <3 weeks post-therapy).

References [return to contents]

  1. Centers for Disease Control and Prevention. Recommendations and Reports: Sexually transmitted diseases treatment guidelines 2010. MMWR. 2010:59(RR-12).

  2. Centers for Disease Control and Prevention. Pelvic inflammatory disease (PID) - CDC Fact Sheet. http://www.cdc.gov/std/PID/STDFact-PID.htm. Accessed June 23, 2013.

  3. Sweet RL. Treatment of acute pelvic inflammatory disease. Infect Dis Obstet Gynecol. 2011;2011:561909.

  4. Centers for Disease Control and Prevention (CDC). Summary of notifiable diseases—United States, 2010. MMWR Morb Mortal Wkly Rep. 2012;59:1-111. Erratum in: MMWR Morb Mortal Wkly Rep. 2012 Jul 27;61:562.

  5. McGowin CL, Anderson-Smits C. Mycoplasma genitalium: an emerging cause of sexually transmitted disease in women. PLoS Pathog. 2011;7:e1001324. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3102684. Accessed June 23, 2013.

  6. Satterwhite CL, Torrone E, Meites E, et al. Sexually transmitted infections among US women and men: prevalence and incidence estimates, 2008. Sex Transm Dis. 2013;40:187-193.

  7. Lau CY, Qureshi AK. Azithromycin versus doxycycline for genital chlamydial infections: a meta-analysis of randomized clinical trials. Sex Transm Dis. 2002;29:497-502.

  8. Centers for Disease Control and Prevention (CDC). Update to CDC’s Sexually transmitted diseases treatment guidelines, 2010: oral cephalosporins no longer a recommended treatment for gonococcal infections. MMWR Morb Mortal Wkly Rep. 2012;61:590-594.

  9. Wiesenfeld HC, Hillier SL, Krohn MA, et al. Lower genital tract infection and endometritis: insight into subclinical pelvic inflammatory disease. Obstet Gynecol. 2002;100:456-463.

  10. Stamm WE, Guinan ME, Johnson C, et al. Effect of treatment regimens for Neisseria gonorrhoeae on simultaneous infection with Chlamydia trachomatis. N Engl J Med. 1984;310:545-549.

  11. Scholes D, Stergaghis A, Heidrich F, et al. Prevention of pelvic inflammatory disease by screening for cervical chlamydial infection. N Engl J Med. 1996;334:1362-1366.

  12. Genc M, Mardh P. A cost-effectiveness analysis of screening and treatment for Chlamydia trachomatis infection in asymptomatic women. Ann Intern Med. 1996;124:1-7.

  13. Wang LY, Burstein GR, Cohen DA. An economic evaluation of a school-based sexually transmitted disease screening program. Sex Transm Dis. 2002;29:737-745.

  14. US Preventive Services Task Force. Screening for gonorrhea. http://www.uspreventiveservicestaskforce.org/
    uspstf/uspsgono.htm. Accessed May 22, 2013.

  15. Nelson HD, Helfand M. Screening for chlamydial infection. Am J Prev Med. 2001;20(Suppl 3):95-107.

  16. Black CM. Current methods of laboratory diagnosis of Chlamydia trachomatis infections. Clin Microbiol Rev. 1997;10:160-184.

  17. Puolakkainen M, Hiltunen-Back E, Reunala T, et al. Comparison of performances of two commercially available tests, a PCR assay and a ligase chain reaction test, in detection of urogenital Chlamydia trachomatis infection. J Clin Microbiol. 1998;36:1489-1493.

  18. Van Dyck E, Ieven M, Pattyn S, et al. Detection of Chlamydia trachomatis and Neisseria gonorrhoeae by enzyme immunoassay, culture, and three nucleic acid amplification tests. J Clin Microbiol. 2001;39:1751-1756.

  19. Gaydos CA, Quinn TC, Willis D, et al. Performance of the APTIMA Combo 2 assay for detection of Chlamydia trachomatis and Neisseria gonorrhoeae in female urine and endocervical swab specimens. J Clin Microbiol. 2003;41:304-309.

  20. Association of Public Health Laboratories. Laboratory Diagnostic Testing for Chlamydia trachomatis and Neisseria gonorrhoeae. Expert Consultation Meeting Summary Report; January 13–15, 2009, Atlanta, GA. http://www.aphl.org/aphlprograms/infectious/std/Documents/ID_2009Jan_CTGCLab-Guidelines-Meeting-Report.pdf. Accessed June 23, 2013.
     

07/2013

 
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