Performance ofChlamydia trachomatisOmcB Enzyme-Linked Immunosorbent Assay in Serodiagnosis ofChlamydia trachomatisInfection in Women

ABSTRACTChlamydia trachomatisserological assays with improved sensitivity over commercially available assays are needed to evaluate the burden ofC. trachomatisinfection and the effectiveness of prevention efforts. We evaluated the performance of aC. trachomatisouter membrane complex protein B (OmcB) enzyme-linked immunosorbent assay (ELISA) in the detection of anti-C. trachomatisantibody responses inC. trachomatis-infected women. OmcB ELISA was less sensitive than ourC. trachomatiselementary body (EB) ELISA, but it was highly specific. The magnitude of the antibody response was higher in African-Americans and those with priorC. trachomatisinfection. Unlike EB ELISA, the IgG1 response toC. trachomatisOmcB was short-lived and was not maintained by repeatC. trachomatisinfection.

Pyocyanin InhibitsChlamydiaInfection by Disabling Infectivity of the Elementary Body and Disrupting Intracellular Growth

ABSTRACTThe obligate intracellular bacteriumChlamydiais a widespread human pathogen that causes serious problems, including (but not limited to) infertility and blindness. Our search for novel antichlamydial metabolites from marine-derived microorganisms led to the isolation of pyocyanin, a small compound fromPseudomonas aeruginosa. Pyocyanin is an effective antichlamydial for all threeChlamydiaspp. tested. It has a 50% inhibitory concentration (IC50) of 0.019 to 0.028 μM, which is comparable to the IC50of tetracycline. At concentrations as low as 0.0039 μM, pyocyanin disables infectivity of the chlamydial elementary body (EB). At 0.5 μM or higher concentrations, the continuous presence of pyocyanin also inhibits chlamydial growth in the inclusion during later stages of the developmental cycle. Oxidative stress, a major known antimicrobial mechanism of pyocyanin, appears to be responsible only for the inhibition of bacterial growth and not for the disinfection of EBs. Pyocyanin is well-tolerated by probiotic vaginalLactobacillusspp. Our findings suggest that pyocyanin is of therapeutic value for chlamydial infections and can serve as a valuable chemical probe for studying chlamydial biology.

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.

Mechanisms of Intracellular Chlamydiae Survival

Chlamydiae are Gram-negative, non-motile, obligate intracellular, and spherically shaped bacteria with a diameter of 0.2-1.5 μm. Chlamydiae are present in several different morphological forms: the elementary body, the reticular body, and in the last several years, there has been the observation of a third form known as the persistent or atypical form. The intracellular localization of Chlamydia provides a unique replication cycle that occurs inside a membrane-surrounded vacuole in the host cell cytoplasm and is significantly different from the method of multiplication of other microorganisms. Chlamydiae are capable of manipulating different signalling pathways inside the infected cell, thus avoiding the host immune response. This ensures intracellular multiplication, survival, and long-term persistence of Chlamydiae. There are two basic means of achieving this persistence: inhibition of apoptosis and manipulation of NF-κB (nuclear factor kappa B)-mediated signals in the host.

Effects ofMentha suaveolensEssential Oil onChlamydia trachomatis

Chlamydia trachomatis, the most common cause of sexually transmitted bacterial infection worldwide, has a unique biphasic developmental cycle alternating between the infectious elementary body and the replicative reticulate body.C. trachomatisis responsible for severe reproductive complications including pelvic inflammatory disease, ectopic pregnancy, and obstructive infertility. The aim of our study was to evaluate whetherMentha suaveolensessential oil (EOMS) can be considered as a promising candidate for preventingC. trachomatisinfection. Specifically, we investigated thein vitroeffects of EOMS towardsC. trachomatisanalysing the different phases of chlamydial developmental cycle. Our results demonstrated that EOMS was effective towardsC. trachomatis, whereby it not only inactivated infectious elementary bodies but also inhibited chlamydial replication. Our study also revealed the effectiveness of EOMS, in combination with erythromycin, towardsC. trachomatiswith a substantial reduction in the minimum effect dose of antibiotic. In conclusion, EOMS treatment may represent a preventative strategy since it may reduceC. trachomatistransmission in the population and, thereby, reduce the number of new chlamydial infections and risk of developing of severe sequelae.