Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-02-13T12:08:13Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatis.pdf: 714575 bytes, checksum: 150b98376e7d5179deaf87cc15123665 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-04-16T14:00:20Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatis.pdf: 714575 bytes, checksum: 150b98376e7d5179deaf87cc15123665 (MD5) / Made available in DSpace on 2014-04-16T14:00:20Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatis.pdf: 714575 bytes, checksum: 150b98376e7d5179deaf87cc15123665 (MD5) Previous issue date: 2010 / As bactérias do gênero Chlamydia estão associadas à diversas doenças, como cegueira, infecções genitais e pneumonia. Existem poucos dados sobre como a Chlamydia e o Treponema pallidum afetam indígenas na Amazônia brasileira. Este estudo objetivou determinar a soroprevalência das infecções pela Chlamydia trachomatis, Chlamydia pneumoniae e Treponema pallidum nas aldeias indígenas Bakajá, Apyterewa, Xingu e Mrotdidjãm, no município de Altamira, Pará, Brasil. O estudo incluiu 270 amostras de sangue coletadas no ano de 2007. A detecção de anticorpos das classes IgM e IgG anti-Chlamydia foi realizada empregando-se o ensaio imunoenzimático (ELISA), e selecionada de forma aleatória amostragem de 36, entre os positivos, para determinar a sorotipagem pela microimunofluorescência. Para detecção de anticorpos anti-T. pallidum foi utilizado um teste treponêmico (ELISA) e as amostras positivas foram submetidas a um teste não treponêmico (RPR). A prevalência geral de anticorpos anti-Chlamydia foi de 26,7%, com prevalência de 100% para C. trachomatis entre as amostras testadas pela MIF. Para a C. pneumoniae a prevalência foi de 61,1% e a prevalência de anticorpos contra Treponema pallidum foi baixa. As bactérias do estudo circulam nas comunidades indígenas da Amazônia brasileira estudada, o que requer uma resposta urgente das autoridades de saúde pública, pois estas bactérias podem causar doenças graves, mas são sensíveis a tratamento específico, quando diagnosticadas adequadamente. / Bacteria from the genius Chlamydia are associated with several diseases including blindness, reproductive tract infections and pneumonias. There is little data about Chlamydia and Treponema pallidum affects on native Indian population in the Brazilian Amazon region. This study determined the prevalence of infections by Chlamydia trachomatis, Chlamydia pneumoniae and Treponema pallidum in Altamira, Para- Brazil among the native Indian populations Bakaja, Apyretewa, Mrotidjam, Xingu and included 270 plasma samples collected in 2007; they were tested using an enzyme immunoassay (ELISA) for the detection of IgM and IgG antibodies to Chlamydia and random samples (36) was chosen from the positives for serotyping through a microimmunofluorescence assay (MIF). Antibodies anti-Treponema were detected using a treponemal (ELISA) test and the positive samples were subjected to a non-treponemal test (RPR). The overall prevalence of antibodies to Chlamydia was 26.7% with a 100% prevalence of C. trachomatis tested through MIF. Prevalence of antibodies to C.pneumoniae was 61.1% and the prevalence of antibodies to T. pallidum was low. This study of bacteria circulating in the Brazilian Amazon indigenous communities confirms that it is necessary for an urgent response from public health authorities, because these bacteria’s can cause serious illness. With adequate diagnoses these bacteria’s can be treated because they are sensitive to specific treatment.

Submitted by Cleide Dantas (cleidedantas@ufpa.br) on 2014-02-13T12:18:42Z No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatisChlamydia.pdf: 2065401 bytes, checksum: 1da33c9028340a826d8e01d04fe2f763 (MD5) / Approved for entry into archive by Ana Rosa Silva (arosa@ufpa.br) on 2014-04-22T13:32:53Z (GMT) No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatisChlamydia.pdf: 2065401 bytes, checksum: 1da33c9028340a826d8e01d04fe2f763 (MD5) / Made available in DSpace on 2014-04-22T13:32:54Z (GMT). No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_SoroepidemiologiaChlamydiaTrachomatisChlamydia.pdf: 2065401 bytes, checksum: 1da33c9028340a826d8e01d04fe2f763 (MD5) Previous issue date: 2009 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A Chlamydia trachomatis e o Treponema pallidum compartilham com o HIV uma importante forma de transmissão: a via sexual. Por conta do comprometimento imunológico dos portadores de HIV, a C. pneumoniae pode apresentar um papel potencial em infecções respiratórias. Este trabalho objetivou a descrição da soroprevalência destes três agentes em portadores de HIV do Estado do Pará, Brasil. Entre setembro de 2007 a junho de 2008, foram coletadas 430 amostras de portadores de HIV em Belém, Pará. Estas foram submetidas a um ELISA para detecção de anticorpo IgG e IgM anti-Chlamydia e, dentre os positivos, uma amostragem aleatória foi escolhida e submetida à microimunofluorescência para sorotipagem. Para a detecção de anticorpos anti-Treponema pallidum foi feito um teste não treponêmico (RPR) e um teste treponêmico (ELISA). Os resultados obtidos foram analisados pelo teste do χ2. A prevalência geral de anticorpos anti-Chlamydia foi 64,2% (51,6% para IgG e 4% para IgM). A sorotipagem mostrou uma alta prevalência de C. trachomatis (100% tanto para IgG como IgM), e C. pneumoniae (73,5% IgG e 70,5% IgM), sendo que houve uma larga disseminação dos sorotipos que causam infecções genitais da Chlamydia trachomatis. A prevalência geral de anticorpos contra o Treponema pallidum foi de 34,9%, sendo que 7,3% apresentaram resultado laboratorial indicativo de sífilis. As variáveis que apresentaram associação com a infecção por Chlamydia e Treponema pallidum foram: o gênero masculino, maior idade, baixa escolaridade, número de parceiros por semana, a prática de sexo anal, homossexualismo/bissexualismo, uso de droga não-endovenosa, histórico de IST. Faz-se necessário tanto a conscientização como o monitoramento da população, para impedir a transmissão destes agentes e para a melhoria da qualidade de vida dos indivíduos portadores de HIV. / Chlamydia trachomatis and Treponema pallidum share the sexual route of transmission with HIV-1. In consequence of the compromise of the immune response among HIV-1 carriers, C. pneumoniae is a potential harassment in respiratory infections. The present study intended the description of the seroprevalence of those three agents among 430 HIV-1 infected persons residing in the State of Para, Brazil, attended at the State Reference Unit (URE-DIPE), between September 2007 to June 2008. Plasma samples were tested using an enzyme immuno assay for the detection of IgM and IgG antibodies to Chlamydia and those which elicited positive results were ramdomly selected for serotyping through a microimmunofluorescence assay. Antibodies to T. pallidum were detected using a flocculation reaction (RPR) and an enzyme immunoassay. Results were compared statistically using the Chi square test (χ2). The general prevalence to Chlamydia was 64.2% (51.6% IgG reactivity and 4% to IgM). Serotyping showed 100% reactivity to C. trachomatis (for both IgG and IgM), a high prevalence to C. pneumoniae (73.5% IgG and 70.5% to IgM) and a large distribution of reactivity to strains of C. trachomatis which cause genital infections. Prevalence of antibodies to T. pallidum was 34.9% and 7.3% showed laboratory evidence of syphilis. Infection with both pathogens were associated to several characteristics which included: higher prevalence among males, high age, low number of study years, high number of sexual partners, anal sexual relations, homosexual/bisexual habits, use of non injecting drugs and the history of sti. It is necessary not only the individual attention for prevention, but also the continuous monitoring to block transmission and the improvement of the well being of HIV-1 infected persons.

Chlamydia trachomatis serovars D-K are the leading cause of bacterially-acquired sexually transmitted infections in the United States. As an obligate intracellular pathogen, C. trachomatis infects columnar epithelial cells of the genital mucosae and can cause deleterious sequelae such as pelvic inflammatory disease, infertility, and ectopic pregnancy. Several chlamydial antigens reach the host cell cytosol prior to the natural release of chlamydiae at the end of the developmental cycle. While some of these extra-inclusion antigens traffic to the host cell surface, others remain intracellular where they are proposed to influence vital host cell functions and antigen trafficking and presentation. The research herein examines the escape and trafficking of the immunodominant chlamydial antigens MOMP, LPS, and cHsp60 within C. trachomatis serovar E-infected polarized human endometrial epithelial cells. Studies using high-resolution transmission electron microscopy (TEM) and immuno-TEM report the novel escape mechanism of chlamydial antigens via vesicles everted/pinched off from the inclusion membrane, an occurrence observed both in the presence and absence of the antibiotic azithromycin. These extra-inclusion vesicles were differentiated from Golgi vesicles and were shown to deliver chlamydial heat shock protein 60 (cHsp60)-homologs 2 and 3, but not homolog 1, to the infected cell surface. Examination of the iron-responsiveness of the three cHsp60 homologs by immuno-TEM revealed a significant increase in cHsp60-2 following iron deprivation. Further investigation of the trafficking of chlamydial MOMP and LPS antigens enveloped within the protective everted inclusion membrane vesicles within host cells involved density gradient centrifugation for the separation of epithelial secretory pathway components followed by SDS-PAGE and Western blot to determine whether the chlamydial antigen-containing vesicles could fuse with and deliver the antigens to host cell organelles. Coupled with immuno-TEM, these data confirmed the presence of major chlamydial antigens within the endoplasmic reticulum of infected host cells. Additionally, chlamydial lipopolysaccharide (LPS) was co-localized with CD1d, a lipid antigen-presenting molecule. Collectively, these studies (i) establish a novel escape mechanism for chlamydial antigens, (ii) identify cHsp60-2 as a marker of iron stress response in C. trachomatis, and (iii) define for the first time the host cell ER as a destination for selected chlamydial antigens during infection.

<p>In recent years molecular biology has become an integral part of the clinical laboratory. With an ever increasing number of methodologies and applications being presented each year it has increased our knowledge of how bacteria cause disease as well as our ability to predict disease outcome. </p><p>The main focus of this thesis has been to develop methods for identifying biomarkers and prediction methods for bacterial infectious diseases by taking advantage of the ever increasing possibilities of molecular biology. We applied cutting edge techniques in order to establish novel platforms for identifying and characterizing biomarkers of disease. </p><p>In paper one we describe a novel approach to measure levels of antibiotic resistance and viability of C. trachomatis, a method that is a clear improvement over existing techniques. In the second paper we describe the development of two assays designed to type pertussis toxin subunit 1 in circulating strains, in order to facilitate multi center studies for vaccine escape surveillance. In paper three we develop a novel microarray application designed to identify a large number of bacterial traits of H. pylori simultaneously with human genetic polymorphisms in order to identify a collection of risk factors that could be used as a prediction tool for gastric cancer risk. In the last paper we define the “antigenome” of H. pylori and identified 14 promising, previously unreported antigens as well as a number of potential biomarkers.</p><p>The platform technologies described in this collection of papers will hopefully help us identifying novel ways of fighting and predicting bacterial disease in future studies. </p>

In recent years molecular biology has become an integral part of the clinical laboratory. With an ever increasing number of methodologies and applications being presented each year it has increased our knowledge of how bacteria cause disease as well as our ability to predict disease outcome. The main focus of this thesis has been to develop methods for identifying biomarkers and prediction methods for bacterial infectious diseases by taking advantage of the ever increasing possibilities of molecular biology. We applied cutting edge techniques in order to establish novel platforms for identifying and characterizing biomarkers of disease. In paper one we describe a novel approach to measure levels of antibiotic resistance and viability of C. trachomatis, a method that is a clear improvement over existing techniques. In the second paper we describe the development of two assays designed to type pertussis toxin subunit 1 in circulating strains, in order to facilitate multi center studies for vaccine escape surveillance. In paper three we develop a novel microarray application designed to identify a large number of bacterial traits of H. pylori simultaneously with human genetic polymorphisms in order to identify a collection of risk factors that could be used as a prediction tool for gastric cancer risk. In the last paper we define the “antigenome” of H. pylori and identified 14 promising, previously unreported antigens as well as a number of potential biomarkers. The platform technologies described in this collection of papers will hopefully help us identifying novel ways of fighting and predicting bacterial disease in future studies.

Arginine decarboxylase is a key enzyme involved in the polyamine pathway of organisms. Pyruvoyl-dependent arginine decarboxylases are expressed in the form of proenzymes that self-cleave to form N-terminal [beta] and C-terminal [alpha] subunits generating an active pyruvoyl group at the [alpha] terminus. We have identified an archaeal homolog of a pyruvoyl-dependent arginine decarboxylase in Chlamydophila pneumoniae that could play a role in the persistence of the organism in the host. The recombinant enzyme showed highest activity at pH 3.4, which is the lowest optimum pH ever reported for a pyruvoyl dependent arginine decarboxylase. The proton-consuming decarboxylation raises intracellular pH, and thereby plays a role in acid-resistance. It could inhibit the pro-inflammatory nitric oxide synthase resulting in asymptomatic infection. A variant protein Thr⁵²Ser at the predicted cleavage site showed less pro-enzyme cleavage and activity compared to the wild-type. The homologs of arginine decarboxylase and flanking arginine-agmatine antiporter were also found in different biovariants of Chlamydia trachomatis. In the invasive L2 strain of C. trachomatis, the presence of a nonsense codon in the gene encoding arginine decarboxylase enzyme prevented the expression of an active enzyme. The variant protein with tryptophan replacing nonsense codon restored arginine decarboxylase activity. The non-invasive D strain of C. trachomatis had an intact arginine decarboxylase gene, but it was recombinantly expressed as a proenzyme that was uncleaved. The arginine-agmatine antiporters from both the strains were active and transported tritiated arginine into their cells. The polyamine pathway of the crenarchaeon Sulfolobus solfataricus uses arginine to make putrescine, but the organism lacks homologs of arginine decarboxylase. However, it has two paralogs of pyruvoyl dependent S-adenosylmethionine decarboxylase − SSO0536 and SSO0585. These enzymes were recombinantly expressed as pro-enzymes that self-cleaved into [beta] and [alpha] subunits. Even with a 47% amino acid sequence identity, the SSO0536 protein exhibited significant arginine decarboxylase activity whereas SSO0585 protein had significant S-adenosylmethionine decarboxylase activity. This is the first report of an S-adenosylmethionine decarboxylase enzyme showing alternative decarboxylase activity. The chimeric protein with the [alpha]-subunit of SSO0585 and [beta]-subunit of SSO0536 had arginine decarboxylase activity, suggesting that the residues responsible for substrate recognition are located in the amino terminus. / text

Chlamydia trachomatis (CT) can cause infertility and is the most common sexually transmitted infection (STI) of bacterial origin in Europe. Surveys in seven countries estimated a population prevalence of 1.4-3.0 % in people 18 to 44 years. Approximately 87% of those diagnosed in Sweden are 15-29 years. Since 1997, with the exception of 2009-2010, despite all efforts, CT has increased steadily in many European countries including Sweden. That made us investigate risk factors associated with catching STIs, especially CT. In Sweden partner notification is mandatory by law when a patient is diagnosed with CT. Centralised partner notification, performed by a few experienced counsellors, and evaluation of the sexual history for at least 12 months back in time, shows superior results compared to other studies. Phone-interviews are a good option in remote areas. “The Västerbotten model” for partner notification fulfils these criteria and our evaluation has functioned as a model for changing recommendations of partner notification in Sweden. Preventing CT by primary prevention such as information and counselling is, however, still of great importance. We investigated whether it was necessary to test for CT in the throat. We found that patients testing positive for pharyngeal CT neither had more symptoms or signs nor a sexual history that differed from others. We therefore believe that we will find most or all of these patients by conventional testing of urine and cervical/vaginal samples. We wanted to further identify risk factors among patients attending a clinic for sexually transmitted infections to enable individualized care depending on risk. None or inconsistent use of condoms with new/temporary partners in combination with having at least one new/temporary partner within the past 6 months could identify persons with risk behaviour and at increased risk of CT (re)infection. Additional information about whether the condom was used during the whole intercourse did not add any risk of infection. A drop-in reception is a good contribution to an opportunistic screening approach. The rate of CT infected is high and the clinic attracts men and individuals ≥25 years old at risk of infection, groups which usually have a reduced test rate. The mean age was 28 years and 58% of the patients were men. The figure of correct condom usage is very low indicating the need for risk reducing counselling also in this grown-population. Among adult STI patients anxiety was common and depression uncommon. Neither was linked to high risk sexual behaviour nor ongoing CT infection. Hazardous alcohol consumption, however, was common and linked to anxiety and high risk sex. We conclude that preventive work can not only focus on STI prevention, but must consider the high frequency of hazardous alcohol consumption, which probably is contributing to sexual risk behaviour.

Although Sweden invests a great deal of money and effort in prevention work, STIs are a major problem in our society. Young people are at high risk both when it comes to unwanted pregnancies and STIs and several studies have revealed that the condom use is quite low. Condom use is a complex issue. There are often several factors that interact and affect the decision to use or not use condom. The result in this thesis shows that young people have behavioral expectation to use condom, especially for anal sex and vaginal sex with a casual partner (both known and unknown). At the same time, the condom use is low irrespective of type of partner and type of sex. Approximately 20 % of the participants never used a condom during the preceding 12 months. Most of the participants said that reason for their use or non-use was based on partner evaluation. However, our participants indicate that there often is a deeper reason why they do not use condoms. Women talk about their male partner’s resistance against condom use. Men in the other hand mention the problem with fit and feel especially problems related to erection problems when they have been drinking alcohol. One of the most interesting findings is that the participants’ view of sex affected their condom use. Those with a relaxed view (e.g., did not connect love with sex and had had more sexual partners during the past 12 months) had fewer occasions of unprotected vaginal intercourse compared with the participants with a traditional view (e.g., often associated sex with vaginal penetration).The most important thing we need to do is increase ’men’s sense of responsibility and involve them in the prevention work. It is also important that the condom counseling is individualized. It is not enough to simply speak about condom use in general; instead we need to relate condom use to sexual practice and partner type but also to the individuals’ specific condom problem. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Epub ahead of print. Paper 2: Manuscript. Paper 3: Manuscript.</p>

Chlamydia trachomatis is an obligate intracellular bacterium of major human health concern, causing urogential chlamydia infections, lymphogranuloma venereum (LGV) and trachoma. Chlamydia is one of the most common sexually transmitted infections worldwide and can cause infertility. In the first four papers described herein we used a high resolution multilocus sequence typing (MLST) system to investigate the epidemiology of C. trachomatis, and showed that MLST is superior to conventional ompA genotyping with respect to resolution. In the fifth paper we simplified the methodology by developing and validating a multilocus typing (MLT) DNA microarray based on the MLST system. In more detail, MLST analysis of consecutive specimens from 2006 in Örebro County in Sweden, and comparison to specimens from 1999-2000, showed that the new variant C. trachomatis (nvCT) is monoclonal and likely has appeared in recent years. MLST analysis of LGV specimens from men who have sex with men (MSM) showed that the increase of LGV in Europe in the last decade indeed was a clonal outbreak, contrary to the USA where LGV might have been present all along. In the third paper, clinical symptoms could not be correlated with the MLST genotypes, suggesting, together with the combined results of all previous studies, that bacterial factors, if important, need to be understood in the context of host factors. MLST analysis of specimens from a high incidence C. trachomatis area in North Norway revealed interesting epidemiological details concerning unusual genetic variants, the nvCT and MSM, but found no significant difference in genetic diversity compared to two other geographic areas in Norway. Lastly, we developed a MLT array that provides high resolution while being rapid and cost-effective, which makes it an interesting alternative for C. trachomatis genotyping. In conclusion, the MLST system and the MLT array have proven to be useful tools and should now be applied in further investigations to improve our understanding of C. trachomatis epidemiology.

Chlamydial infections have been associated with several chronic human diseases, including trachoma, pelvic inflammatory disease, chronic obstructive pulmonary disease and atherosclerotic cardiovascular disease. In Chlamydia-associated disease, the organisms are believed to exist in an atypical, persistent phase that is not well understood at the genetic level. The research presented in this thesis investigated chlamydial gene expression in in vitro cell culture models of persistence. The first set of studies analysed a continuous-infection model of persistence that has been recently developed for two C. pneumoniae isolates (TW-183 and CM-1). The spontaneous establishment and unique cyclical nature of continuous infections could be particularly relevant to in vivo events. An initial analysis using a semi-quantitative reverse transcriptase PCR (sqRT-PCR) approach provided evidence of differential gene expression in C. pneumoniae TW-183 continuous infections relative to acute control infections. Using a subsequently established fully quantitative real-time reverse transcriptase PCR (rtRT-PCR) assay, up-regulated expression profiles were confirmed for five genes (CPn0483, nlpD, ompA, pmp1 and porB) in the continuous C. pneumoniae TW-183 infections. The omcB, pmp1 and porB genes, all of which encode membrane proteins, showed similar patterns of expression over both the acute and continuous time courses tested. Gene expression data for a second C. pneumoniae isolate, CM-1, revealed similar overall expression trends to those seen for C. pneumoniae TW-183 but also supported previous observations of different growth characteristics between the two isolates in the continuous-infection model. The rtRT-PCR assay was further optimised for use in gene expression studies of the gamma interferon (IFN-γ)-mediated model of C. pneumoniae A-03 persistence, in which altered growth and morphological traits typical of chlamydial persistence have been well characterised. Meanwhile, chlamydial genes such as euo, ftsK and hctB were emerging from the literature as reliable genetic markers of persistence. Therefore, a preliminary rtRT-PCR analysis of marker gene expression was used to assess the likely extent of persistence in individual IFN-γ-treated C. pneumoniae A-03 infections from a series of experiments that had been prepared for this persistence model. In this way, an appropriate pair of duplicate experiments was selected for further studies based on strong genetic evidence of persistence in IFN-γ-treated samples at 48 h post-infection (PI) in those experiments. Using rtRT-PCR, 14 genes of interest from the related peptidoglycan, aminosugars and lipopolysaccharide (LPS) biosynthetic pathways were analysed in the validated experiments of the IFN-γ-mediated C. pneumoniae A-03 persistence model. Selective up- and down-regulated expression trends were associated with IFN-γ-treatment at 48 h PI for genes encoding products that are located at specific enzymatic points in these pathways. Most strikingly, the expression of glmU, the product of which controls the amount of an essential precursor metabolite that enters both peptidoglycan and LPS biosynthesis, was strongly and reproducibly down-regulated in the 48-h PI IFN-γ-treated samples. This expression profile may contribute to a reduced rate of peptidoglycan biosynthesis in this persistence model and may therefore be related to the inhibited cell division and RB-to-EB differentiation that characterise chlamydial persistence. While most other genes in these pathways showed unchanged expression associated with IFN-γ treatment, murA and kdsB (from peptidoglycan and LPS biosynthesis, respectively) were selectively up-regulated in the 48-h PI IFN-γ-treated samples. Taken together, these data supported the concept of a persistence stimulon in C. pneumoniae that is regulated at key points in various metabolic pathways. In addition to the analysis of biosynthetic genes, the up-regulated gene set from continuous C. pneumoniae TW-183 infections was also analysed in the validated IFN-γ-mediated C. pneumoniae A-03 persistence experiments. The data revealed similarities and differences in gene expression patterns between these two in vitro persistence models. Furthermore, the profiles obtained for genes such as pmp1 and porB provided insights into the widely predicted phenomenon of late developmental gene shut-down during chlamydial persistence. A final investigation into an analogous IFN-γ-mediated persistence system for C. trachomatis serovar L2 focussed on one up-regulated (murA) and one down-regulated (glmU) gene from the validated IFN-γ-mediated persistent C. pneumoniae A-03 data set. Both genes were significantly down-regulated in persistent C. trachomatis, adding to a growing body of evidence for key differences among chlamydial species in their persistent gene expression patterns. This project has contributed significantly to our understanding of the molecular basis of the important persistent phase of chlamydial development.