Article

Duration of Untreated, Uncomplicated Chlamydia trachomatis Genital Infection and Factors Associated with Chlamydia Resolution: A Review of Human Studies

Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, AL 35294-0007, USA.
The Journal of Infectious Diseases (Impact Factor: 5.78). 06/2010; 201 Suppl 2(supplement 2):S104-13. DOI: 10.1086/652402
Source: PubMed

ABSTRACT The majority of Chlamydia trachomatis genital infections in humans are asymptomatic and without clinical evidence of complications at the time of diagnosis. The natural history of chlamydial infection in humans, including the duration of infection and factors influencing resolution of infection, is not yet completely understood. This is in part attributable to the inherent challenges and ethical considerations in studying untreated chlamydia in humans. An improved understanding of the natural history of chlamydia in humans has implications for chlamydia screening and treatment recommendations. In April 2008, the Centers for Disease Control and Prevention convened an advisory group for the Chlamydia Immunology and Control Expert Advisory Meeting, in which studies related to chlamydia natural history, pathogenesis, and immunobiology were reviewed and gaps in our knowledge that would have implications for prevention and control of C. trachomatis infection were identified. This article summarizes the key questions posed and the evidence reviewed on the duration of untreated, uncomplicated genital chlamydial infection in humans and the factors associated with chlamydia resolution.

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    • "Chlamydia was reported within 12 years for over 20% of all women and over 36% of black women in Florida who were aged 15e17 years in 2000. This underestimates the risk of infection for all women because many women were not screened every year, and therefore many infections could resolve without being detected or reported [27]. We further underestimated the risk for black women because race/ethnicity was missing for 18.4% of reported cases. "
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    ABSTRACT: Chlamydia trachomatis is a very common infection among young women in the United States; information on cumulative risk of infection is limited. We sought to estimate the cumulative risk of chlamydial infection for young women. We measured cumulative risk of reported chlamydial infection for 14- to 34-year-old women in Florida between 2000 and 2011 using surveillance records and census estimates. We calculated reported infections per woman, analyzed first infections to get cumulative risk, and calculated risk of repeat infection over the 12-year period. There were 457,595 infections reported among 15- to 34-year-old women. Reports increased annually from 25,390 to 51,536. Nineteen-year-olds were at highest risk with 5.1 infections reported per 100 women in 2011. There were 341,671 different women infected. Among women aged 14-17 years in 2000, over 20% had at least one infection reported within 12 years, and among blacks, this risk was over 36%, and that underestimates risk because 18% of cases were missing race/ethnicity information. Repeat infections were common. Among 53,109 with chlamydia at the age of 15-20 years during 2000-2003, 36.7% had additional infections reported by 2011. More than one out of five women in Florida was reported as having chlamydia during her young-adult years; risk was highest for black women. True infection risks were likely much higher because many infections were not diagnosed or reported. Young women who had chlamydia were very likely to get reinfected. Rates of infection remain high despite years of screening. More information is needed on how to prevent chlamydial infection.
    Journal of Adolescent Health 08/2014; 55(2):241-246. DOI:10.1016/j.jadohealth.2014.02.006 · 2.75 Impact Factor
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    • "Chlamydia was reported within 12 years for over 20% of all women and over 36% of black women in Florida who were aged 15e17 years in 2000. This underestimates the risk of infection for all women because many women were not screened every year, and therefore many infections could resolve without being detected or reported [27]. We further underestimated the risk for black women because race/ethnicity was missing for 18.4% of reported cases. "
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    ABSTRACT: Purpose Chlamydia trachomatis is a very common infection among young women in the United States; information on cumulative risk of infection is limited. We sought to estimate the cumulative risk of chlamydial infection for young women. Methods We measured cumulative risk of reported chlamydial infection for 14- to 34-year-old women in Florida between 2000 and 2011 using surveillance records and census estimates. We calculated reported infections per woman, analyzed first infections to get cumulative risk, and calculated risk of repeat infection over the 12-year period. Results There were 457,595 infections reported among 15- to 34-year-old women. Reports increased annually from 25,390 to 51,536. Nineteen-year-olds were at highest risk with 5.1 infections reported per 100 women in 2011. There were 341,671 different women infected. Among women aged 14–17 years in 2000, over 20% had at least one infection reported within 12 years, and among blacks, this risk was over 36%, and that underestimates risk because 18% of cases were missing race/ethnicity information. Repeat infections were common. Among 53,109 with chlamydia at the age of 15–20 years during 2000–2003, 36.7% had additional infections reported by 2011. Conclusions More than one out of five women in Florida was reported as having chlamydia during her young-adult years; risk was highest for black women. True infection risks were likely much higher because many infections were not diagnosed or reported. Young women who had chlamydia were very likely to get reinfected. Rates of infection remain high despite years of screening. More information is needed on how to prevent chlamydial infection.
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    • "Several lines of evidence indicate genital C. trachomatis infection induces human immunity and that this immunity is variably protective, as reviewed recently (Batteiger et al., 2010). These include: (a) young age as a significant risk factor for infection acquisition (Arno et al., 1994); (b) reduced organism load with repeat infections (Barnes et al., 1990); (c) natural history studies documenting spontaneous resolution of infection (Parks et al., 1997; Golden et al., 2000; Joyner et al., 2002; Morre et al., 2002; Molano et al., 2005; Centers for Disease Control, 2010; Geisler, 2010); and (d) association of spontaneous resolution of infection with subsequent protection from incident disease (Geisler et al., 2013). Immunity in humans appears to develop slowly and protection from infection is generally thought to be robust only after multiple exposures and can be as short as several months (Katz et al., 1987; Molano et al., 2005), a finding corroborated in animal models (Rank and Whittum-Hudson, 2010). "
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    ABSTRACT: The natural history of genital Chlamydia trachomatis infections can vary widely; infections can spontaneously resolve but can also last from months to years, potentially progressing to cause significant pathology. The host and bacterial factors underlying this wide variation are not completely understood, but emphasize the bacterium's capacity to evade/adapt to the genital immune response, and/or exploit local environmental conditions to survive this immune response. IFNγ is considered to be a primary host protective cytokine against endocervical C. trachomatis infections. IFNγ acts by inducing the host enzyme indoleamine 2,3-dioxgenase, which catabolizes tryptophan, thereby depriving the bacterium of this essential amino acid. In vitro studies have revealed that tryptophan deprivation causes Chlamydia to enter a viable but non-infectious growth pattern that is termed a persistent growth form, characterized by a unique morphology and gene expression pattern. Provision of tryptophan can reactivate the bacterium to the normal developmental cycle. There is a significant difference in the capacity of ocular and genital C. trachomatis serovars to counter tryptophan deprivation. The latter uniquely encode a functional tryptophan synthase to synthesize tryptophan via indole salvage, should indole be available in the infection microenvironment. In vitro studies have confirmed the capacity of indole to mitigate the effects of IFNγ; it has been suggested that a perturbed vaginal microbiome may provide a source of indole in vivo. Consistent with this hypothesis, the microbiome associated with bacterial vaginosis includes species that encode a tryptophanase to produce indole. In this review, we discuss the natural history of genital chlamydial infections, morphological and molecular changes imposed by IFNγ on Chlamydia, and finally, the microenvironmental conditions associated with vaginal co-infections that can ameliorate the effects of IFNγ on C. trachomatis.
    Frontiers in Cellular and Infection Microbiology 06/2014; 4:72. DOI:10.3389/fcimb.2014.00072 · 2.62 Impact Factor
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