Efficacy of an Immune Modulator in Experimental Chlamydia trachomatis Infection of the Female Genital Tract

Objective. The aim of this study was to determine if vaginal application of the immune response modifier imiquimod (Aldara cream, 3M Pharmaceuticals, St Paul, Minn) would alter the course and/or outcome of female genital tract infection with a human isolate of Chlamydia trachomatis in a murine model. Methods. Groups of CF-1 mice were treated with Aldara on three different schedules: (1) ongoing beginning 5 days prior to and continuing through day 5 of infection; (2) a single prophylactic dose 2 hours prior to infection; and (3) therapeutic from day 4 to day 14 of infection. Mice were infected vaginally with a serovar D strain of C trachomatis, and monitored by culture to determine the level of shedding and duration of infection. Results. We observed a significant reduction in both duration of infection and the level of shedding during the acute phase in mice treated on an ongoing basis commencing 5 days prior to infection. There was no effect with respect to the other regimens. Conclusion. These results demonstrate that ongoing Aldara treatment has efficacy and may enhance local innate immunity which reduces the duration of subsequent infection with human isolates of C trachomatis in a murine model of female genital tract infection

Slow Epidemic of Lymphogranuloma Venereum L2b Strain

We traced the Chlamydia trachomatis L2b variant in Amsterdam and San Francisco. All recent lymphogranuloma venereum cases in Amsterdam were caused by the L2b variant. This variant was also present in the 1980s in San Francisco. Thus, the current "outbreak" is most likely a slowly evolving epidemic

Multi locus sequence typing of Chlamydiales: clonal groupings within the obligate intracellular bacteria Chlamydia trachomatis

<p>Abstract</p> <p>Background</p> <p>The obligate intracellular growing bacterium <it>Chlamydia trachomatis </it>causes diseases like trachoma, urogenital infection and lymphogranuloma venereum with severe morbidity. Several serovars and genotypes have been identified, but these could not be linked to clinical disease or outcome. The related <it>Chlamydophila pneumoniae</it>, of which no subtypes are recognized, causes respiratory infections worldwide. We developed a multi locus sequence typing (MLST) scheme to understand the population genetic structure and diversity of these species and to evaluate the association between genotype and disease.</p> <p>Results</p> <p>A collection of 26 strains of <it>C. trachomatis </it>of different serovars and clinical presentation and 18 strains of <it>C. pneumoniae </it>were included in the study. For comparison, sequences of <it>C. abortus, C. psittaci</it>, <it>C. caviae</it>, <it>C. felis</it>, <it>C. pecorum </it>(<it>Chlamydophila</it>), <it>C. muridarum </it>(<it>Chlamydia</it>) and of <it>Candidatus protochlamydia </it>and <it>Simkania negevensis </it>were also included. Sequences of fragments (400 – 500 base pairs) from seven housekeeping genes (<it>enoA</it>, <it>fumC</it>, <it>gatA</it>, <it>gidA</it>, <it>hemN</it>, <it>hlfX</it>, <it>oppA</it>) were analysed. Analysis of allelic profiles by eBurst revealed three non-overlapping clonal complexes among the <it>C. trachomatis </it>strains, while the <it>C. pneumoniae </it>strains formed a single group. An UPGMA tree produced from the allelic profiles resulted in three groups of sequence types. The LGV strains grouped in a single cluster, while the urogenital strains were distributed over two separated groups, one consisted solely of strains with frequent occurring serovars (E, D and F). The distribution of the different serovars over the three groups was not consistent, suggesting exchange of serovar encoding <it>ompA </it>sequences. In one instance, exchange of <it>fumC </it>sequences between strains of different groups was observed. Cluster analyses of concatenated sequences of the Chlamydophila and Chlamydia species together with those of <it>Candidatus Protochlamydia amoebophila </it>and <it>Simkania negevensis </it>resulted in a tree identical to that obtained with 23S RNA gene sequences.</p> <p>Conclusion</p> <p>These data show that <it>C. trachomatis </it>and <it>C. pneumoniae </it>are highly uniform. The difference in genetic diversity between <it>C. trachomatis </it>and <it>C. pneumoniae </it>is in concordance with a later assimilation to the human host of the latter. Our data supports the taxonomy of the order of <it>Chlamydiales</it>.</p

Do host genetic traits in the bacterial sensing system play a role in the development of Chlamydia trachomatis-associated tubal pathology in subfertile women?

BACKGROUND: In women, Chlamydia (C.) trachomatis upper genital tract infection can cause distal tubal damage and occlusion, increasing the risk of tubal factor subfertility and ectopic pregnancy. Variations, like single nucleotide polymorphisms (SNPs), in immunologically important host genes are assumed to play a role in the course and outcome of a C. trachomatis infection. We studied whether genetic traits (carrying multiple SNPs in different genes) in the bacterial sensing system are associated with an aberrant immune response and subsequently with tubal pathology following a C. trachomatis infection. The genes studied all encode for pattern recognition receptors (PRRs) involved in sensing bacterial components. METHODS: Of 227 subfertile women, serum was available for C. trachomatis IgG antibody testing and genotyping (common versus rare allele) of the PRR genes TLR9, TLR4, CD14 and CARD15/NOD2. In all women, a laparoscopy was performed to assess the grade of tubal pathology. Tubal pathology was defined as extensive peri-adnexal adhesions and/or distal occlusion of at least one tube. RESULTS: Following a C. trachomatis infection (i.e. C. trachomatis IgG positive), subfertile women carrying two or more SNPs in C. trachomatis PRR genes were at increased risk of tubal pathology compared to women carrying less than two SNPs (73% vs 33% risk). The differences were not statistically significant (P = 0.15), but a trend was observed. CONCLUSION: Carrying multiple SNPs in C. trachomatis PRR genes tends to result in an aberrant immune response and a higher risk of tubal pathology following a C. trachomatis infection. Larger studies are needed to confirm our preliminary findings

Study protocol: The Dutch 20|30 Postmeningitis study: a cross-sectional follow-up of two historical childhood bacterial meningitis cohorts on long-term outcomes

BACKGROUND: Bacterial meningitis (BM) is a serious, life-threatening infectious disease of the central nervous system that often occurs in young children. The most common severe to moderate sequelae following BM are sensorineural hearing loss, neuromotor disabilities and mental retardation, while subtle sequelae include academic and behavioral disabilities. It is largely unknown whether these more subtle sequelae persist into adolescence and adulthood. Therefore, this study will investigate the very long-term effects of childhood BM in later life. Better understanding of long-term effects and early identification of adverse outcomes after BM are essential for more timely interventions. Additionally, certain single nucleotide polymorphisms (SNPs) are associated with disease severity and might predict adverse sequelae. These include SNPs in genes encoding for pathogen recognition and immune response upon infection. Accordingly, a secondary objective of this study is to investigate the role of genetic variation in BM and use any insights to predict short- and long-term outcomes. METHODS: In the Dutch 20|30 Postmeningitis study, adolescents and young adults (n = 947) from two historical cohorts with a prior episode of BM during childhood will be enrolled into a cross-sectional follow-up investigation using mainly questionnaires that examine executive and behavioral functioning, health-related quality of life, subjective hearing, mood and sleeping disorders, academic performance, and economic self-sufficiency. The results will be compared to normative data by one-sample t-tests. Multivariable regression analysis will be used to assess for any associations with causative pathogens and severity of BM. Participants that complete the questionnaires will be approached to provide a swab for buccal DNA and subsequent sequencing analyses. Logistic regression models will be used to predict sequelae. DISCUSSION: The unique follow-up duration of this cohort will enable us to gain insights into the possible very long-term adverse effects of childhood BM and how these might impact on quality of life. The investigation of host genetic factors will contribute to the development of prediction models which will serve as prognostic tools to identify children who are at high risk of adverse outcome after BM. TRIAL REGISTRATION: Dutch Trial Register NTR-6891. Retrospectively registered 28 December 2017

Chlamydia trachomatis Test-of-Cure Cannot Be Based on a Single Highly Sensitive Laboratory Test Taken at Least 3 Weeks after Treatment

Current test-of-cure practice in patients with Chlamydia trachomatis (Ct) infection is to confirm cure with a single test taken at least 3 weeks after treatment. Effectiveness of single-time-point testing however lacks a scientific evidence basis and the high sensitivity of laboratory assays nowadays in use for this purpose may compromise the clinical significance of their results. Prospectively following 59 treated Ct infections, administering care as usual, the presence of Ct plasmid DNA and rRNA was systematically assessed by multiple time-sequential measurements, i.e. on 18 samples taken per patient during 8 weeks following treatment with a single dose of 1000 mg Azythromycin. A high proportion (42%) of Ct infections tested positive on at least one of the samples taken after 3 weeks. Patients' test results showed substantial inter-individual and intra-individual variation over time and by type of NAAT used. We demonstrated frequent intermittent positive patterns in Ct test results over time, and strongly argue against current test-of-cure practice

Single Nucleotide Polymorphisms in TLR9 Are Highly Associated with Susceptibility to Bacterial Meningitis in Children

Background. Bacterial meningitis (BM) is a severe infection mainly caused by Streptococcus pneumoniae and Neisseria meningitidis (NM). However, genetically determined susceptibility to develop severe infections by these microorganisms is variable between individuals. Toll-like receptor 9 (TLR9) recognizes bacterial DNA leading to intracellular inflammatory signaling. Single nucleotide polymorphisms (SNPs) within the TLR9 gene are associated with susceptibility to several diseases, no such association with meningitis has been described. Methods. We studied the role of TLR9 SNPs in host defense against BM. Two TLR9 SNPs and 4 TLR9 haplotypes were determined in 472 survivors of BM and compared to 392 healthy controls. Results. Carriage of the TLR912848-A mutant was significantly decreased in meningococcal meningitis (MM) patients compared with controls (p: .0098, odds ratio [OR]: .6, 95% confidence interval [CI]: .4-.9). TLR9 haplotype I was associated with an increased susceptibility to MM (p: .0237, OR 1.3, 95% CI: 1.0-1.5). In silico analysis shows a very strong immunoinhibitory potential for DNA of NM upon recognition by TLR9 (CpG index of -106.8). Conclusions. We report an association of TLR9 SNPs with susceptibility to BM, specifically MM indicating a protective effect for the TLR912848-A allele. We hypothesize that the TLR912848-A mutant results in an upregulation of TLR9 induced immune response compensating the strong inhibitory potential of NM CpG DNA. BACKGROUN