Chlamydia trachomatis Sexually Transmitted Infections Funmi Adewale MLS 205 - Microbiology

Objectives After the presentation, the audience will be able to: Summarize the natural history of the sexually transmitted infection Chlamydia Outline the life cycle of the bacterial species Chlamydia trachomatis Determine which serotypes of Chlamydia trachomatis are most associated with STIs Propose explanations for the recent trends in Chlamydia prevalence Discriminate between the various diagnostic methods for Chlamydia trachomatis according to their targets, specificities and sensitivities Assess which specimens are acceptable and which diagnostic methods are recommended given the patient circumstances Describe treatment options for patients diagnosed with Chlamydia trachomatis STIs Predict future trends in prevalence based on public health prevention efforts

Chlamydia 2nd most common sexually transmitted infection (STI) in US after HPV; most common bacterial STI Caused by infection with Chlamydia trachomatis Obligate intracellular parasite (cannot make ATP) Infects non-ciliated columnar cells (conjunctiva, urogenital tract, rectum, pharynx) Transmitted through sexual intercourse Most initial infections are asymptomatic; last for months to years Repeat infections are common Easily treated Retrieved from Mahon, C., Lehman, D. & Manuselis, G. (2015). Textbook of diagnostic microbiology. Maryland Heights, Missouri: Elsevier/Saunders.

Risk Factors Age (< 25) Race (infection 5 times greater in blacks compared to whites) Sexual Activity # of partners new partners Men who have sex with men (MSM)* Retrieved from Torrone, E., Papp, J., & Weinstock, H. (2014). Prevalence of Chlamydia trachomatis Genital Infection Among Persons Aged 14-39 Years - United States, 2007-2012. MMWR: Morbidity & Mortality Weekly Report, 63(38), 834-838. *not much known (~6% positivity rate as of CDC’s monitoring in 2005)

Clinical Presentation Retrieved from http://www.drugs.com/mcd/cervicitis Clinical Presentation Majority of infections are asymptomatic Primary symptoms Cervicitis in women Nongonococcal urethritis in men (progresses to epididymitis) Sequelae include: Pelvic inflammatory disease (infection/inflammation of uterus, fallopian tubes, ovaries, peritoneal cavity) Ectopic pregnancy Tubal infertility Lymphogranuloma venerium (a more severe disease caused by L1-3 serovars, rarely seen in the US) In neonates, can lead to: Pneumonia Conjunctivitis Retrieved from http://www.riversideonline.com/health_reference/Mens-Health/DS00603.cfm Mucopurulent discharge Upper tract infection; Most common cause of epididymitis LGV is invasive (lymphatics) and rarely seen in US

Life Cycle of C. trachomatis Retrieved from Mahon, C., Lehman, D. & Manuselis, G. (2015). Textbook of diagnostic microbiology. Maryland Heights, Missouri: Elsevier/Saunders. Elementary body (EB): infectious, metabolically inactive, extracellular and enveloped (Gram-negative elements = LPS) Reticulate body (RB): non-infectious, metabolically active, intracellular Diagnostic text

Structural & Genetic Features Serotyping based on: Major outer membrane protein (MOMP), species specific Serovars D-K responsible for non-LGV STIs Lipopolysaccharide (LPS), genus specific Genetics Cryptic plasmid (>99% of C. trachomatis) Retrieved from Land, J. A., Van Bergen, J. E., Morre, S. A., & Postma, M. J. (2010). Epidemiology of chlamydia trachomatis infection in women and the cost-effectiveness of screening. Human Reproduction Update, 16(2), 189-204. Unknown purpose

Diagnosis: Methods Culture Non-culture Recommended method for diagnosis and legal investigation of code 600 in children Culture Shell vial method 96-well microtiter plate method Non-culture Surface Antigens (MOMP or LPS) Direct fluorescent antibody (DFA) tests Enzyme immunoassays Nucleic Acid Nucleic acid probe tests Nucleic acid amplification testing Recommended method for screening/diagnosis (code 600 in adults) Shell vial is more accurate than 96-well b/c it requires more inoculum and has less risk of cross-contamination Blind pass: 1st incubation monolayer is disturbed and used to reinoculate 2nd monolayer to improve sensitivity Analysis: light microscopy visualization for cytopathic effect, stain w/ fluorescein-conjugated mAb for visualization Issues w/ culture: turnaround time, poor standardization, labor intensive, requires technical skill, highly-dependent on specimen quality DFA: specimen rolled onto slide, flooded with a stain of fluorescein-labeled mAb that react with either MOMP or LPS (cross-reactivity!) antigens EIA: antibodies react with LPS (cross-reactivity!), then detected through enzyme assay (e.g. HRP)

Diagnosis: Methods Retrieved from Mahon, C., Lehman, D. & Manuselis, G. (2015). Textbook of diagnostic microbiology. Maryland Heights, Missouri: Elsevier/Saunders. Culture has poor sensitivity (missing a lot of infections), but excellent specificity (gold standard)

Diagnosis: Specimens Specimen of choice (according to CDC recommendations) Men: urine (as good as or superior to urethral swabs) Women: vaginal swab (as good as endocervical swabs) In women, urine is acceptable for screening, but may reduce sensitivity (up to 10 percent of infections missed) Extragenital sites: rectal and oropharyngeal (not much research, but amplification tests recommended) Collection, transport and storage Transport media for swabs varies depending on diagnostic method Regardless of method, should be refrigerated (4°C) immediately Long-term storage ranges from -10°C to -30°C for varying durations And less invasive

Prognosis & Treatment Excellent prognosis, given of treatment compliance Single-dose oral azithromycin OR 1-week course of doxycycline Expedited partner therapy: prescribing medication for sexual partner of diagnosed patient without examining partner Proven to reduce repeat infections in females Sanctioned by the CDC As of 2010, only legal in 27 states

Prevention: Screening CDC recommends annual screening for: ALL sexually-active women under the age of 25 Sexually-active women 25 and over IF determined to be at increased risk (e.g. new or multiple sexual partners) Men who have sex with men (MSM) CDC also recommends screening for repeat infection 3-12 months after initial diagnosis No screening recommended for heterosexual men UNLESS: High prevalence settings (e.g. correctional facilities) Partners of infected women Barriers to screening: insurance (young adults), privacy (adolescents), awareness, provider-failure to offer screening BYOP (bring your own partner; when patients are called and informed of positive results, advised to bring partner with them during follow-up)

Chlamydia trachomatis STIs: Summary Most prevalent bacterial STI in United States Obligate intracellular parasite of columnar epithelium Serovars D-K cause most of the infections seen in US Nucleic acid amplification testing is recommended diagnostic method (except in children) Theoretically easy to reduce prevalence Easy to prevent transmission (safe sex practices e.g. free condoms by mail in CA) Easy to minimize spread (sensitive diagnostic methods => less invasive specimen collection => increased screening/more accurate diagnostic testing) Easily treated Areas that need improvement Increasing initial screening rates, especially in at-risk populations (under age of 25, blacks, MSM) Free, at home test-kits by mail in Los Angeles Increasing reinfection testing by providers 3-12 months after initial infection CA Health Dept (Family Health Council) LA Health Dept

References Abram, S. (2014, July 22). Rise in chlamydia, gonorrhea cases renew call for std home test kits for women. LA Daily News. Retrieved from http://www.dailynews.com/health/20140722/rise-in-chlamydia-gonorrhea-cases-renew-call-for-std-home-test-kits-for-women CDC Grand Rounds: Chlamydia Prevention: Challenges and Strategies for Reducing Disease Burden and Sequelae. (2011). MMWR: Morbidity & Mortality Weekly Report, 60(12), 370-373. Holmes, K. (2008). Sexually transmitted diseases. New York: McGraw-Hill Medical. Land, J. A., Van Bergen, J. E., Morre, S. A., & Postma, M. J. (2010). Epidemiology of chlamydia trachomatis infection in women and the cost-effectiveness of screening. Human Reproduction Update, 16(2), 189-204. Mahon, C., Lehman, D. & Manuselis, G. (2015). Textbook of diagnostic microbiology. Maryland Heights, Missouri: Elsevier/Saunders. Papp, J. R., Schachter, J., Gaydos, C. A., & Van Der Pol, B. (2014). Recommendations for the Laboratory-Based Detection of Chlamydia trachomatis and Neisseria gonorrhoeae -- 2014. MMWR Recommendations & Reports, 63(2), 1-19. Steinberg, J. (2015, February 18). Free condom-by-mail program set for san bernardino county. San Bernardino County Sun. Retrieved from http://www.sbsun.com/health/20150218/free-condom-by-mail-program-set-for-san-bernardino-county/1 Torrone, E., Papp, J., & Weinstock, H. (2014). Prevalence of Chlamydia trachomatis Genital Infection Among Persons Aged 14-39 Years - United States, 2007-2012. MMWR: Morbidity & Mortality Weekly Report, 63(38), 834-838.