Chlamydia, caused by the bacterium Chlamydia trachomatis, is one of the most important sexually-transmitted infections globally. In addition to accounting for millions of cases every year, the disease causes numerous irreversible complications such as chronic pelvic pain, infertility in females and pelvic inflammatory disease. This thesis presents a number of mathematical models, of the form of deterministic systems of non-linear differential equations, for gaining qualitative insight into the transmission dynamics and control of Chlamydia within an infected host (in vivo) and in a population. The models designed address numerous important issues relating to the transmission dynamics of Chlamydia trachomatis, such as the roles of immune response, sex structure, time delay (in modelling the latency period) and risk structure (i.e., risk of acquiring or transmitting infection). The in-host model is shown to have a globally-asymptotically stable Chlamydia-free equilibrium whenever a certain biological threshold is less than unity. It has a unique Chlamydia-present equilibrium when the threshold exceeds unity. Unlike the in-host model, the two-group (males and females) population-level model undergoes a backward bifurcation, where a stable disease-free equilibrium co-exists with one or more stable endemic equilibria when the associated reproduction number is less than unity. This phenomenon, which is shown to be caused by the re-infection of recovered individuals, makes the effort to eliminate the disease from the population more difficult. Extending the two-group model to incorporate risk structure shows that the backward bifurcation phenomenon persists even when recovered individuals do not acquire re-infection. In other words, it is shown that stratifying the sexually-active population in terms of risk of acquiring or transmitting infection guarantees the presence of backward bifurcation in the transmission dynamics of Chlamydia in a population. Finally, it is shown (via numerical simulations) that a future Chlamydia vaccine that boosts cell-mediated immune response will be more effective in curtailing Chlamydia burden in vivo than a vaccine that enhances humoral immune response. The population-level impact of various targeted treatment strategies, in controlling the spread of Chlamydia in a population, are compared. In particular, it is shown that the use of treatment could have positive or negative population-level impact (depending on the sign of a certain epidemiological threshold).

Chlamydia trachomatis infections are among the most frequently reported causes of human sexually transmitted infection. In Australia, the reported rate of infection in 2004 reached 175 per 100,000 population, the highest rate since surveillance of the condition began in 1991. Severe adverse sequelae that commonly occur following progression of the infection from the lower to the upper genital tract include pelvic inflammatory disease, infertility and ectopic pregnancy. However the frequent prevalance of asymptomatic infection makes diagnosis and treatment often late and therefore ineffective against upper genital tract complications. Hence there is a great need to develop a vaccine to protect against the sexual transmission of C.trachomatis. Despite many years of research investigating potential vaccine strategies to prevent sexually transmitted C.trachomatis infections, there remains no commercially available C.trachomatis vaccine. Early research showed that the use of live, attenuated or inactivated whole Chlamydia as a vaccine was not a viable option due to adverse effects caused by immunopathogenic cellular components. The early human vaccine trials that utilized whole chlamydial cells and resulted in exacerbated disease when immunized individuals were re-exposed to Chlamydia have led to the investigation of chlamydial subunit components as potential vaccine antigens. The most widely investigated vaccine candidate antigen is the major outer membrane protein (MOMP) as it is known to be immunogenic and surface exposed. Much research using this antigen has been undertaken with the antigen being delivered as a protein, peptide or DNA, via many mucosal and systemic routes of immunization, and in combination with various vaccine adjuvants. However, at best only partial protection against a chlamydial genital tract infection has been achieved. Only a few alternative candidate antigens have been investigated as potential vaccine targets to protect against chlamydial infections. These include the outer membrane porin PorB, the large cysteine rich outer membrane protein Omp2 and the heat shock proteins DnaK and GroEL. Although other candidate antigens have been predicted in various models of chlamydial infection (Finco et al., 2005; Stemke-Hale et al., 2005; Li et al., 2006), few have been tested for their protective efficacy. The aim of this study was to use expression library immunization to screen the whole C.muridarum genome for novel vaccine candidates capable of protecting against a chlamydial genital tract infection. C.muridarum was selected as the disease model for chlamydial genital tract infection as it has similarities to C.trachomatis in pathogenesis, immune response to infection and gene content and order. Once protective antigens had been isolated from an expression library, these were screened individually for immunogenicity and protective efficacy in the C.muridarum model of infection. An expression library containing over 21,000 recombinant C.muridarum clones was constructed and divided into pools of clones. DNA was extracted from these pools and used to immunize mice through gene gun technology, delivering 1μg of DNA to the abdomen of mice. Following the immunization regime, mice were challenged intra-vaginally with live C.muridarum as this route of infection best resembles the natural route of infection that is responsible for the sexual transmission of C.trachomatis in humans. Four in vivo screens of the C.muridarum expression library, each time using reduced numbers of clones, resulted in the identification of seven novel vaccine antigens that conferred protection against a genital tract challenge infection in mice. These warrant further investigation as vaccine antigens in the development of a vaccine against C.trachomatis infection. The identified antigens include antigens not conventionally believed to be potential vaccine candidates such as hypothetical proteins and housekeeping genes, including a DNA gyrase subunit, TC0462, and the ATP-dependent Clp protease, ATP-binding subunit ClpC, TC0559. Other antigens identified were more traditional, surface exposed vaccine targets that have not been previously investigated as vaccine targets, including a novel outer membrane protein, TC0512, a polymorphic membrane protein, TC0693, and TC0850, a protein of the type three secretion system, a family of proteins that allow gram-negative bacteria to inject virulence related proteins into the cytoplasm of a host cell. All antigens were shown to be partially protective with the putative outer membrane protein TC0512 showing an overall reduction in chlamydial burden of 55% and other antigens showing overall reductions in chlamydial burden of 26 - 44%. These antigens were also either capable of stimulating an immune response, or predicted to contain epitopes that may stimulate strong immune responses and so warrant further investigation as vaccine antigens to protect against chlamydial genital tract infections. The results of this research demonstrate that it is possible to identify novel vaccine targets through screening an expression library in a disease model. This study has identified several novel vaccine targets that are partially-protective against a C.muridarum infection and that are thought to be capable of stimulating strong immune responses. These antigens have high homology with C.trachomatis sequences, indicating that they have potential as vaccine candidates capable of protecting against the serovars of C.trachomatis that cause sexually transmitted infections in humans. Although the protection observed in this study was only partial, the immunization strategy utilised only fragments of the genes, an immunization mechanism known to elicit Th2 type immune responses, and no adjuvant to enhance the immunogenicity of the antigens. Through different immunization routes and in conjunction with adjuvants that stimulate Th1 type immune responses, complete protection against chlamydial genital tract infections may be achieved.

Chlamydia trachomatis is a human pathogen of the genital tract and ocular epithelium. It is an obligate intracellular parasite with a unique biphasic development cycle. C.trachomatis infection is the most common bacterial sexually transmitted disease in industrialized nations. Its ability to cause chronic disease makes it a serious economic burden and health threat to developed and developing countries. Although treatable, approximately 70% of C.trachomatis infections are asymptomatic, potentially leading to the development of chronic sequelae. Furthermore, chlamydial genital tract infection has been associated with an increased risk of cervical cancer and human immunodeficiency virus infection. Consequently, the development of an efficacious vaccine is the most convenient, potentially reliable and cost effective option to control chlamydial infection and disease complications. Anti-chlamydial protective immunity is essentially mediated by a T helper, type 1 (Th1), response that is dependent upon the presentation of antigen via major histocompatibility (MHC) class II molecules. While antibody secreting cells are not critical components of the primary effector response, they have been shown to be important for clearance of re-infection. Thus an ideal vaccine would be one capable of inducing both a strong Th1 T cell response and a strong mucosal antibody response. Currently there are very few efficacious vaccine candidates that have been identified and characterized. More specifically, there is only a limited number of known T cell antigens processed and presented by the human leukocyte antigen (HLA) class II molecules. This type of antigen is going to be essential to the development of an efficacious chlamydial vaccine. In this study we have identified a number of unique vaccine candidates using a novel in silico approach. In an attempt to overcome HLA polymorphism the whole chlamydial genome was screened for proteins containing epitopes predicted to bind multiple HLA class II molecules (i.e. predicted ‘promiscuous’ T cell epitopes). A wide range of HLA class II molecules were used in this screen to identify vaccine antigens that could potentially offer broad and ethnically balanced population coverage. This analysis identified a number of novel targets and was validated by the identification of a known chlamydial T cell epitope. A selection of these target proteins was cloned, expressed and purified. Recombinant protein was screened against serum samples from patients with both acute and chronic chlamydial infections. Two novel targets, hypothetical protein CT425 and ribonucleotide reductase small chain protein (NrdB) were identified as being immunoreactive. The in vivo protective efficacy of NrdB was analyzed using a mouse model. CD4+ T cells were harvested from NrdB immunized mice and adoptively transferred to naïve mice, which were subsequently infected at the genital site. NrdB immunization was found to confer a CD4+ T cell driven degree of protection similar to that seen with CD4+ T cells primed from a live challenge. The adjuvants and route of immunization used ensured immunological responses were initiated at both the systemic and local sites of infection. Immunization elicited a predominant Th1 response with primed T cells producing high levels of interferon gamma, an essential requirement for the development of an efficacious chlamydial vaccine. Furthermore, high titres of antigen specific IgG and IgA were produced following immunization, with sera derived antibodies demonstrating neutralization properties. NrdB is a highly conserved chlamydial protein with an essential role in the replication of chlamydiae and could play a central role in a multi-subunit vaccine against chlamydial genital tract infections.

The asymptomatic nature of chlamydial infection renders the differential diagnosis of acute and chronic infection difficult. An untreated Chlamydia trachomatis infection can become chronic, result in disease sequelae such as salpingitis and pelvic inflammatory disease (PID), and ultimately culminate in tubal occlusion and infertility. Diagnostic tests for C. trachomatis such as nucleic acid amplification testing (PCR), antigen detection and serological methods have variable performance capabilities with respect to sensitivity, specificity and stage of infection. The use of PCR as a diagnostic tool is somewhat limited, as specimen collection is routinely sampled from the lower genital tract; hence, infections in the fallopian tube where inflammatory damage is most significant, escape detection. Furthermore, PCR can only detect selected Chlamydia DNA sequences from readily accessible sites of the genital tract, and therefore cannot differentiate between acute and chronic infection. Other serological assays aim to discriminate the various stages of C. trachomatis infection through identification of key antigens. The efficacy of these assays however is impeded due to cross-reactivity between chlamydial species and the subsequent antibody response against the target antigen is not restricted to patients with a specific stage of infection. To identify antibody responses capable of differentiating various states of chlamydial infection, samples were collected from both men and women given the variability of immune responses between the two genders. Samples were assigned to a patient group according to infection status and then probed against protein extracts of HEp-2 cells infected with C. trachomatis serovar L2 and HEp-2 cells pre-treated with IFN-γ and infected with C. trachomatis serovar L2. (persistence cell culture) Serological analysis revealed the presence of five antigens (denoted bands A, B, C, D and M) which were shown to be differential between patient groups. Identification of bands B and C by N-terminal sequencing provided two possible candidates for each antigen, ie. CT727 and CT396 (band B) and CT157 and CT423 (band C). In contrast, band M which was unique to males was a PmpB (probable outer membrane protein B) fragment. The four target antigens (CT157, CT423, CT727 and CT396) were expressed as recombinant proteins using autoinduction media and were subsequently probed by both male and female sera to evaluate their diagnostic potential. Results showed that two chlamydial antigenic targets (CT157 and CT727) have the potential to discriminate between acute and chronic C. trachomatis infection. However, since only a small number of samples (n = 3) were used for this aspect of the study, the findings should simply be viewed as preliminary. In females, sensitivity and specificity values were derived using various combinations of the four target antigens into a panel format for the purpose of detecting chronic C. trachomatis infections. The preferred format was B + C with a sensitivity and specificity of 80% and 84% respectively. Using the IFN-γ-mediated persistence model, only two of the five antigenic targets were shown to be differentially expressed. PmpB in males and CT157 (the most likely band C candidate) in females were shown to be up-regulated to varying degrees in samples across the patient groups. We also demonstrated that no other chlamydial antigens are up-regulated during a persistent C. trachomatis infection. In conclusion, although combinations of bands A, B, C, D and M differentiate between male and female patient groups under normal chlamydial growth conditions, during IFN-γ-induced persistence, only bands C (CT157) and M (CT413 - PmpB) are up-regulated thus suggesting a potential role in chronic C. trachomatis infection.

Diss. (sammanfattning) Stockholm : Karol inst., 2004. / Härtill 4 uppsatser.

Thesis (M.Med.Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 35-42). Also available in print.

Made available in DSpace on 2013-08-07T19:04:49Z (GMT). No. of bitstreams: 1 000422377-Texto+Completo-0.pdf: 884424 bytes, checksum: 00e9c69f02bdc012c466f39cf67939e7 (MD5) Previous issue date: 2010 / The metabolic syndrome (MS) comprises a cluster of risk factors for atherosclerotic disease. Pathogens such as Chlamydia pneumoniae and Helycobacter pylori may be involved on triggering and perpetuation of atherogenesis, but their relationship with MS is rather unknown. Exposition to Chlamydia trachomatis (CT) in patients with MS has been unexplored in the literature up to date. Objective: to evaluate the association, if any, of IgA and IgG anti-CT antibodies and occurrence of MS. Methods: in this cross-sectional study, patients with MS with and without previous cardiovascular disease and age and age and sex-matched controls were evaluated. MS diagnosis was based on NCEP criteria. IgA and IgG anti-CT antibodies were detected by immunoenzymatic assay; titers above 1. 1 units were considered as positive. The chi-squared test was utilized for comparison of categoric variables, and the t test for continuous variables. To estimate the association of anti-CT antibodies and MS, odds ratios were calculated. Logistic regression was utilized for adjustment of age and sex. Results. The total survey included 238 individuals: 101 patients (42. 5%) with MS without cardiac events; 47 (19. 7%) with MS and previous cardiac events; and 90 (37. 8%) healthy controls. Females predominated in the 3 groups of patients. The global mean age was 59. 7 years. The prevalence of a positive test for IgA anti-CT was higher in patients with MS (17%) than in controls (6%) (P=0. 015). Elevated levels of IgA anti-CT associated significantly with occurrence of MS in comparison to healthy controls after adjustment for sex and age (OR=3. 4; CI95% 1. 2-9,4; P=0. 015). In the subgroup analysis, elevated levels of IgA anti-CT were more prevalent in non-complicated MS than in controls (P=0. 013). After adjustment for age and sex, the association of IgA anti-CT with non-complicated MS remained defined (OR=3. 6; CI95% 1. 32-10,2; P=0. 015). Conclusions: IgA anti-CT antibodies, possibly of acute phase, were more prevalent in MS than in healthy controls. A positive test for IgA anti-CT associated particularly to noncomplicated MS. The role of such IgA response in patients with MS should be detailed in forecoming studies. / A síndrome metabólica (SM) compreende um conjunto de fatores de risco para doença aterosclerótica. Patógenos como Chlamydia pneumoniae e Helicobacter pylori podem estar envolvidos no deflagramento e perpetuação da aterogênese, mas sua relação com a SM é desconhecida. A exposição à Chlamydia trachomatis (CT) em pacientes com SM não foi explorada na literatura até o momento. Objetivo: Avaliar a associação, se existente, entre anticorpos IgA e IgG anti-CT e ocorrência de SM. Métodos: Neste estudo transversal, foram avaliados pacientes com SM com e sem eventos cardíacos prévios e controles sadios pareados por sexo e idade. O diagnóstico de SM se fundamentou nos critérios do NCEP. Anticorpos IgA e IgG anti-CT foram detectados por ensaio imunoenzimático; títulos acima de 1,1 unidades foram considerados positivos para ambos os isotipos. O teste do qui-quadrado foi utilizado para comparação das variáveis categóricas, e o teste t para comparação de variáveis contínuas. Para estimar a associação entre anticorpos anti-CT e SM, odds ratios (OR) foram calculados. Regressão logística foi utilizada para o ajuste das variáveis sexo e idade. Resultados: O número total da amostra foi de 238 indivíduos: 101 pacientes (42,5%) com SM sem eventos cardíacos; 47 (19,7%) com SM e eventos cardíacos prévios; e 90 (37,8%) controles sadios. O sexo feminino predominou nos 3 grupos. A média global de idade foi 59,7 anos. A prevalência de teste positivo para IgA anti-CT foi maior em pacientes com SM (17%) do que em controles (6%) (P=0,015). Níveis elevados de IgA anti-CT se associaram significativamente com ocorrência de SM na comparação com controles sadios após ajuste para sexo e idade (OR=3,4; IC95% 1,2-9,4; P=0,015). Na análise de subgrupos, níveis elevados de IgA anti-CT foram mais prevalentes na SM não-complicada do que nos controles (P=0,013). Após ajuste para sexo a idade, a associação entre IgA anti-CT e SM nãocomplicada se manteve definida (OR=3,6; IC95% 1,32-10,2; P=0,015). Conclusões: Anticorpos IgA anti-CT, possivelmente de fase aguda, foram mais prevalentes na SM do que em controles sadios. Um teste positivo para IgA anti-CT se associou particularmente à ocorrência de SM não-complicada. O papel da resposta IgA anti- CT em pacientes com SM deve ser detalhado em estudos futuros.

Orientador: Cristina Maria Garcia de Lima Parada / Coorientador: Márcia Guimarães da Silva / Banca: Maria Antonieta de Barros Leite Carvalhaes / Banca: Marli Terezinha Cassamassimo Duarte / Banca: Sandra Marisa Pelloso / Banca: Flávia Gomes-Sponhoz / Resumo: O objetivo geral deste estudo foi analisar o resultado perinatal de gestantes submetidas a busca ativa de infecção genital inferior. Para alcance deste objetivo foram realizados três subprojetos, apresentados em capítulos. Capítulo I- Infecção do trato genital inferior e repercussões perinatais: revisão integrativa da literatura, teve por objetivo identificar, na produção científica dos últimos 10 anos, evidências sobre as condições dos neonatos ao nascimento, quando a mãe apresentou infecção do trato genital inferior na gravidez. Os resultados foram variados, sendo que os estudos apontaram associação de determinado tipo de infecção a alguns desfechos e não a outros. A associação mais frequentemente buscada foi entre vaginose bacteriana e prematuridade, tendo sido apontada associação em seis estudos e ausência em três. Capítulo II - Resultado perinatal de gestantes submetidas à busca ativa de infecção do trato genital inferior: estudo observacional e analítico, teve por objetivo analisar o resultado perinatal de gestantes de baixo risco submetidas à busca ativa de infecção genital. Observou-se que a chance do índice de Apgar de primeiro minuto ser inferior a sete pontos foi significativamente menor entre as gestantes que passaram pela busca ativa e esse grupo teve recém-nascidos com peso ao nascer em média 350 gramas maior. Capítulo III: Resultado perinatal de mulheres com história de trabalho de parto prematuro e submetidas à busca ativa de infecção do trato genital inferior, objetivou comparar a frequência de prematuridade e de índice de Apgar de primeiro minuto de vida inferior a sete em gestantes submetidas ou não a busca ativa de infecções do trato genital inferior e tratamento etiológico. Estudo controlado, não randomizado, não encontrou relação significativa entre busca ativa e menores taxas de prematuridade e melhores índices de Apgar. Conclui-se que, pela relevância do tema para ... / Abstract: This paper aimed at evaluate perinatal results of pregnant women who were submitted to an active search of inferior genital infection. Three sub-projects were developed in chapters in order to reach this objective. Chapter 1 - Infection of the lower genital tract and perinatal outcomes: a literature review. The purpose was to identify in 10 years scientific production, evidences of neonatal conditions at birth when the mother presented genital tract infection during pregnancy. The results differed. The studies showed an association of certain types of infection in some outcomes and not in others. The most frequently searched association was among bacterial vaginitis and prematurity, present in six cases and absent in three of them. Chapter II - Perinatal outcome of pregnant women submitted to an active search of the lower genital tract infection; observational and analytical study. The purpose was to evaluate the perinatal result of low risk pregnant women submitted to an active search of genital infection. In this case, the chance of first minute Agpar score to be less than 7 points was significantly smaller among pregnant women who underwent an active search. Newborns in this group weighed 350 grams more. Chapter III - Perinatal results of women who experienced premature labor and were submitted to an active search of inferior genital tract infection. The purpose was to compare prematurity frequency and first minute Apgar score, inferior to seven, in pregnant women submitted or not to an active search of the inferior genital tract and etiological treatment. The study was controlled and non randomized. A significative relationship between an active search and lower prematurity indexes and better Agpar scores was found. The study leads to the conclusion that considering the relevance of the subject for public health, the results should be seen as a first approach. Further investigations on special controlled studies with larger ... / Doutor

Made available in DSpace on 2015-05-14T16:53:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-05-29Bitstream added on 2015-05-14T16:59:05Z : No. of bitstreams: 1 000816181.pdf: 1313890 bytes, checksum: 785f61dc5b28f498e5dd5476b29eaed5 (MD5) / O objetivo geral deste estudo foi analisar o resultado perinatal de gestantes submetidas a busca ativa de infecção genital inferior. Para alcance deste objetivo foram realizados três subprojetos, apresentados em capítulos. Capítulo I- Infecção do trato genital inferior e repercussões perinatais: revisão integrativa da literatura, teve por objetivo identificar, na produção científica dos últimos 10 anos, evidências sobre as condições dos neonatos ao nascimento, quando a mãe apresentou infecção do trato genital inferior na gravidez. Os resultados foram variados, sendo que os estudos apontaram associação de determinado tipo de infecção a alguns desfechos e não a outros. A associação mais frequentemente buscada foi entre vaginose bacteriana e prematuridade, tendo sido apontada associação em seis estudos e ausência em três. Capítulo II - Resultado perinatal de gestantes submetidas à busca ativa de infecção do trato genital inferior: estudo observacional e analítico, teve por objetivo analisar o resultado perinatal de gestantes de baixo risco submetidas à busca ativa de infecção genital. Observou-se que a chance do índice de Apgar de primeiro minuto ser inferior a sete pontos foi significativamente menor entre as gestantes que passaram pela busca ativa e esse grupo teve recém-nascidos com peso ao nascer em média 350 gramas maior. Capítulo III: Resultado perinatal de mulheres com história de trabalho de parto prematuro e submetidas à busca ativa de infecção do trato genital inferior, objetivou comparar a frequência de prematuridade e de índice de Apgar de primeiro minuto de vida inferior a sete em gestantes submetidas ou não a busca ativa de infecções do trato genital inferior e tratamento etiológico. Estudo controlado, não randomizado, não encontrou relação significativa entre busca ativa e menores taxas de prematuridade e melhores índices de Apgar. Conclui-se que, pela relevância do tema para ... / This paper aimed at evaluate perinatal results of pregnant women who were submitted to an active search of inferior genital infection. Three sub-projects were developed in chapters in order to reach this objective. Chapter 1 - Infection of the lower genital tract and perinatal outcomes: a literature review. The purpose was to identify in 10 years scientific production, evidences of neonatal conditions at birth when the mother presented genital tract infection during pregnancy. The results differed. The studies showed an association of certain types of infection in some outcomes and not in others. The most frequently searched association was among bacterial vaginitis and prematurity, present in six cases and absent in three of them. Chapter II - Perinatal outcome of pregnant women submitted to an active search of the lower genital tract infection; observational and analytical study. The purpose was to evaluate the perinatal result of low risk pregnant women submitted to an active search of genital infection. In this case, the chance of first minute Agpar score to be less than 7 points was significantly smaller among pregnant women who underwent an active search. Newborns in this group weighed 350 grams more. Chapter III - Perinatal results of women who experienced premature labor and were submitted to an active search of inferior genital tract infection. The purpose was to compare prematurity frequency and first minute Apgar score, inferior to seven, in pregnant women submitted or not to an active search of the inferior genital tract and etiological treatment. The study was controlled and non randomized. A significative relationship between an active search and lower prematurity indexes and better Agpar scores was found. The study leads to the conclusion that considering the relevance of the subject for public health, the results should be seen as a first approach. Further investigations on special controlled studies with larger ...

Made available in DSpace on 2014-12-17T14:13:52Z (GMT). No. of bitstreams: 1 MariaJPMAS_DISSERT.pdf: 273368 bytes, checksum: c02a1aa6459a551cbcb0946cc1cab047 (MD5) Previous issue date: 2011-05-06 / Universidade Federal do Rio Grande do Norte / Introdu??o: As doen?as sexualmente transmiss?veis (DSTs) tem sido um alvo importante das pol?ticas p?blicas de sa?de. O aumento crescente destas enfermidades em diferentes popula??es denuncia as limita??es e falhas dos programas de rastreamento e controle destas enfermidades. Entre as DSTs, destaca-se a infec??o clamidiana por ser a DST bacteriana mais prevalente em todo o mundo, acometendo principalmente mulheres na fase reprodutiva e cursando freq?entemente com importantes seq?elas no trato genital, que adquirem especial import?ncia durante o per?odo gestacional. Por outro lado, a morbidade desta infec??o durante a gesta??o tem sido apresentada na literatura com dados divergentes e n?o conclusivos, havendo assim a necessidade de esclarecimentos quanto ao real impacto desta infec??o durante este per?odo. Objetivo: Avaliar o efeito da infec??o por Chlamydia trachomatis na gesta??o sob a morbimortalidade perinatal. M?todos: Foi realizada revis?o sistem?tica com metan?lise, em base de dados eletr?nica e manual, combinando descritores espec?ficos buscando alta sensibilidade para responder o objetivo da pesquisa. Os artigos considerados de alta qualidade metodol?gica (pontua??o superior a 6 na escala de Newcastle-Ottawa) foram avaliados por metan?lise. Resultados: Foram inclu?dos 12 estudos para c?lculo de estimativa-sum?rio por Mantel Haenszel com intervalo de confian?a 95%. Observou-se que a infec??o por clam?dia na gesta??o aumentou o risco de trabalho de parto prematuro (RR= 1.35 [1.11-1.63]), rotura prematura de membranas (RR= 1.13 [0.95- 1.34]), baixo peso ao nascimento (RR= 1.52 [1.2-, 1.87]) e mortalidade perinatal (RR= 1.84 [1.15- 2.94]). N?o se evidenciou aumento de risco associado ? infec??o por clam?dia no que tange a abortamento ou endometrite p?s-parto com RR= 1.20 [0.65- 2.20] e 0.89 [0.49- 1.61] respectivamente. Conclus?o: O diagn?stico e tratamento da endocervicite por chlamydia trachomatis durante a gesta??o pode reduzir a morbimortalidade perinatal associada a esta infec??o, por?m ensaios cl?nicos s?o necess?rios para confirma??o destes dados