Inhibition of the futalosine pathway for menaquinone biosynthesis suppresses Chlamydia trachomatis infection.

Chlamydia trachomatis, an obligate intracellular bacterium with limited metabolic capabilities, possesses the futalosine pathway for menaquinone biosynthesis. Futalosine pathway enzymes have promise as narrow-spectrum antibiotic targets, but the activity and essentiality of chlamydial menaquinone biosynthesis have yet to be established. In this work, menaquinone-7 (MK-7) was identified as a C. trachomatis-produced quinone through liquid chromatography-tandem mass spectrometry. An immunofluorescence-based assay revealed that treatment of C. trachomatis-infected HeLa cells with the futalosine pathway inhibitor docosahexaenoic acid (DHA) reduced inclusion number, inclusion size, and infectious progeny. Supplementation with MK-7 nanoparticles rescued the effect of DHA on inclusion number, indicating that the futalosine pathway is a target of DHA in this system. These results open the door for menaquinone biosynthesis inhibitors to be pursued in antichlamydial development.

Environmental factors and hygiene behaviors associated with facial cleanliness and trachoma in Kongwa, Tanzania.

BACKGROUND: Having a clean face is protective against trachoma. In the past, long distances to water were associated with unclean faces and increased trachoma. Other environmental factors have not been extensively explored. We need improved clarity on the environmental factors associated with facial cleanliness and trachoma prevalence, especially when the disease burden is low. METHODOLOGY/PRINCIPLE FINDINGS: A cross-sectional survey focusing on household environments was conducted in all 92 villages in Kongwa, Tanzania, in a random selection of 1798 households. Children aged 0-5 years in these households were examined for facial cleanliness. In each of the 50 randomly-selected villages, 50 children aged 1-9 years were randomly selected and examined for trachoma. In a multivariate model adjusting for child age, we found that children were more likely to have clean faces if the house had a clean yard (OR 1.62, 95% CI 1.37-1.91), an improved latrine (OR 1.11, 95% CI 1.01-1.22), and greater water storage capacity (OR 1.02, 95% CI 1.00-1.04), and if there were clothes washed and drying around the house (OR 1.30, 95% CI 1.09-1.54). However, measures of crowding, wealth, time spent on obtaining water, or the availability of piped water was not associated with clean faces. Using a cleanliness index (clean yard, improved latrine, washing clothes, ≥1 child in the household having a clean face), the community prevalence of trachoma decreased with an increase in the average value of the index (OR 2.28, 95% CI 1.17-4.80). CONCLUSIONS/SIGNIFICANCE: Access to water is no longer a significant limiting factor in children's facial cleanliness in Kongwa. Instead, water storage capacity and the way that water is utilized are more important in facial cleanliness. A household cleanliness index with a holistic measure of household environment is associated with reduced community prevalence of trachoma.

Antichlamydial Dimeric Indole Derivatives from Marine Actinomycete Rubrobacter radiotolerans.

Chlamydiae are widely distributed pathogens of human populations, which can lead to serious reproductive and other health problems. In our search for novel antichlamydial metabolites from marine derived-microorganisms, one new (1) and two known (2, 3) dimeric indole derivatives were isolated from the sponge-derived actinomycete Rubrobacter radiotolerans. The chemical structures of these metabolites were elucidated by NMR spectroscopic data as well as CD calculations. All three metabolites suppressed chlamydial growth in a concentration-dependent manner. Among them, compound 1 exhibited the most effective antichlamydial activity with IC50 values of 46.6 ~ 96.4 µM in the production of infectious progeny. Compounds appeared to target the mid-stage of the chlamydial developmental cycle by interfering with reticular body replication, but not directly inactivating the infectious elementary body.

An optimized, fast-to-perform mouse lung infection model with the human pathogen Chlamydia trachomatis for in vivo screening of antibiotics, vaccine candidates and modified host-pathogen interactions.

Chlamydia trachomatis causes sexually transmitted diseases with infertility, pelvic inflammatory disease and neonatal pneumonia as complications. The duration of urogenital mouse models with the strict mouse pathogen C. muridarum addressing vaginal shedding, pathological changes of the upper genital tract or infertility is rather long. Moreover, vaginal C. trachomatis application usually does not lead to the complications feared in women. A fast-to-perform mouse model is urgently needed to analyze new antibiotics, vaccine candidates, immune responses (in gene knockout animals) or mutants of C. trachomatis. To complement the valuable urogenital model with a much faster and quantifiable screening method, we established an optimized lung infection model for the human intracellular bacterium C. trachomatis serovar D (and L2) in immunocompetent C57BL/6J mice. We demonstrated its usefulness by sensitive determination of antibiotic effects characterizing advantages and limitations achievable by early or delayed short tetracycline treatment and single-dose azithromycin application. Moreover, we achieved partial acquired protection in reinfection with serovar D indicating usability for vaccine studies, and showed a different course of disease in absence of complement factor C3. Sensitive monitoring parameters were survival rate, body weight, clinical score, bacterial load, histological score, the granulocyte marker myeloperoxidase, IFN-γ, TNF-α, MCP-1 and IL-6.

Activation of epidermal growth factor receptor is required for Chlamydia trachomatis development.

BACKGROUND: Chlamydia trachomatis (C. trachomatis) is a clinically significant human pathogen and one of the leading causative agents of sexually transmitted diseases. As obligate intracellular bacteria, C. trachomatis has evolved strategies to redirect the host's signaling and resources for its own survival and propagation. Despite the clinical notoriety of Chlamydia infections, the molecular interactions between C. trachomatis and its host cell proteins remain elusive. RESULTS: In this study, we focused on the involvement of the host cell epidermal growth factor receptor (EGFR) in C. trachomatis attachment and development. A combination of molecular approaches, pharmacological agents and cell lines were used to demonstrate distinct functional requirements of EGFR in C. trachomatis infection. We show that C. trachomatis increases the phosphorylation of EGFR and of its downstream effectors PLCγ1, Akt and STAT5. While both EGFR and platelet-derived growth factor receptor-ß (PDGFRß) are partially involved in bacterial attachment to the host cell surface, it is only the knockdown of EGFR and not PDGFRß that affects the formation of C. trachomatis inclusions in the host cells. Inhibition of EGFR results in small immature inclusions, and prevents C. trachomatis-induced intracellular calcium mobilization and the assembly of the characteristic F-actin ring at the inclusion periphery. By using complementary approaches, we demonstrate that the coordinated regulation of both calcium mobilization and F-actin assembly by EGFR are necessary for maturation of chlamydial inclusion within the host cells. A particularly important finding of this study is the co-localization of EGFR with the F-actin at the periphery of C. trachomatis inclusion where it may function to nucleate the assembly of signaling protein complexes for cytoskeletal remodeling required for C. trachomatis development. CONCLUSION: Cumulatively, the data reported here connect the function of EGFR to C. trachomatis attachment and development in the host cells, and this could lead to new venues for targeting C. trachomatis infections and associated diseases.

The added value of water, sanitation, and hygiene interventions to mass drug administration for reducing the prevalence of trachoma: a systematic review examining.

Trachoma is the leading cause of infectious blindness worldwide. The SAFE strategy, the World Health Organization-recommended method to eliminate blinding trachoma, combines developments in water, sanitation, surgery, and antibiotic treatment. Current literature does not focus on the comprehensive effect these components have on one another. The present systematic review analyzes the added benefit of water, sanitation, and hygiene education interventions to preventive mass drug administration of azithromycin for trachoma. Trials were identified from the PubMed database using a series of search terms. Three studies met the complete criteria for inclusion. Though all studies found a significant change in reduction of active trachoma prevalence, the research is still too limited to suggest the impact of the "F" and "E" components on trachoma prevalence and ultimately its effects on blindness.

Higher expression of ferritin protects Chlamydia trachomatis infected HeLa 229 cells from reactive oxygen species mediated cell death.

Apoptosis plays an important role in modulating the pathogenesis of a variety of infectious diseases. Chlamydial infection protects cells against different forms of apoptosis: extrinsic, intrinsic, and granzyme B mediated. Redox reactions are central to the life and death decision of cells and pathogens and an intimate relationship exists between oxidative stress and iron metabolism. The link between redox status and ferritin was largely unexplored in chlamydia-infected cells. In the present study, we showed that Chlamydia trachomatis (CT) infection induced FHC protein in HeLa cells. FHC induction by CT-infected cells stably expressing FHC blunted ROS production compared with mock infected cells, and the infected cells were relatively resistant to apoptosis induced by H2O2. We also demonstrated that endogenous FHC overexpression correlates well with the stabilization of the mitochondrial membrane potential in CT-infected cells. Increased expression of FHC is independent of iron supplementation (FAC) and depletion (DFO) in CT-infected cells. These data suggest that FHC up-regulation is an acute response of HeLa cells against CT infection and that FHC exerts anti-apoptotic activity against oxidative stress.

Neglected diseases caused by bacterial infections.

Bacterial infections represent a major health problem, especially in third world countries. In endemic regions, large populations of people are greatly affected, but the medical care is very limited. In this review, the neglected diseases buruli ulcer and trachoma are elucidated. Buruli ulcer is caused by Mycobacterium ulcerans which produces an outstanding immunosuppressive toxin mycolactone that induces an ulcerative, necrotic skin disease. Until today, only the combination of rifampin/streptomycin is used to treat buruli ulcer. However, this therapy is ineffective and expensive. Here, we report new findings that suggest pharmaceutical formulations such as rifapentine, in combination with clarithromycin or moxifloxacin that have shown promising results in mice footpad trials. Moreover, alternative treatment options such as heat therapy, nitric oxide cremes and French clay show bactericidal effects. The genotyping of M. ulcerans also promises new ways of finding drug targets and vaccines. Trachoma, induced by the bacterium Chlamydia trachomatis, is the primary infectious cause of blindness worldwide. Recurrent infections lead to chronic inflammation of the upper tarsal conjunctiva. As a consequence, scarring and distortion of the eye lids occur, eventually resulting in blindness. First-line medications for trachoma treatment are bacteriostatic agents such as topically applied tetracylines and systematically administered azithromycin. Surgery, environmental improvements and personal hygiene are further crucial factors in controlling trachoma. Moreover, efforts are being undertaken towards the development of vaccine systems, with the major outer membrane protein and the polymorphic membrane protein acting as attractive candidates.

The pig-tailed macaque rectal model: microflora and chlamydial infection.

BACKGROUND: A topical microbicide should protect against acquisition of sexually transmitted infection during both vaginal and rectal intercourse. The rectal microflora of the Macaca nemestrina (pig-tailed macaque) and humans were examined, as well as the histopathology of rectal tissues. In a subset of macaques, a human rectal isolate of Chlamydia trachomatis was inoculated into the rectum to establish rectal chlamydial infection. GOAL: To evaluate the comparability of the pig-tailed macaque rectal model with humans. STUDY DESIGN: Rectal swabs were collected for microbiologic analysis to characterize normal microflora in pig-tailed macaques and humans. Subsequently, 10 macaques received a rectal inoculation with C trachomatis, serovar D, prepared from a clinical rectal isolate. RESULTS: The rectal microflora of pig-tailed macaques (n = 80) were found to be comparable with the rectal flora of humans (n = 40). The prevalence of Lactobacillus in the rectum was higher in the macaques than in humans. Coliform and Enterococcus were decreased in the macaques, as compared with those of humans. In 9 of 10 macaques, rectal chlamydial infection was confirmed by culture or ligase chain reaction on days 2, 7, and 14 after inoculation. The test results were positive for rectal chlamydial infection by ligase chain reaction only for the remaining animal on day 14 after inoculation. CONCLUSIONS: The findings demonstrate that the rectal environment of the pig-tailed macaque is a useful model for further evaluation of newly developed topical microbicides for rectal use. Furthermore, such products can be evaluated for protection against rectal chlamydial infection in this model.

Pathogenetic role of Chlamydia, Yersinia and Borrelia in undifferentiated oligoarthritis.

We studied the cellular and humoral immune response to Chlamydia trachomatis, Yersinia enterocolitica and Borrelia burgdorferi in paired samples of peripheral blood and synovial fluid (SF) in undifferentiated oligoarthritis, reactive arthritis (ReA) and rheumatoid arthritis. Antigen specific lymphocyte proliferation was found in SF of 43% of patients with ReA and 34% of patients with undifferentiated oligoarthritis. C. trachomatis was the most frequent single agent. HLA-B27 was positive in 83% of patients with ReA and in 62% of patients with undifferentiated oligoarthritis with antigen specific lymphocyte proliferation. Antigen specific lymphocyte proliferation correlated poorly with the specific antibody response. Only chlamydial antigen was detected in SF cells using monoclonal antibodies. We conclude that some patients with undifferentiated oligoarthritis may have a forme fruste of ReA. This finding is important in view of recent evidence supporting the efficacy of antibiotic therapy in ReA.