Nonactivated titanium-dioxide nanoparticles promote the growth of Chlamydia trachomatis and decrease the antimicrobial activity of silver nanoparticles.

AIMS: Chlamydia trachomatis and herpes simplex virus (HSV) are the most prevalent bacterial and viral sexually transmitted infections. Due to the chronic nature of their infections, they are able to interact with titanium-dioxide (TiO2 ) nanoparticles (NPs) applied as food additives or drug delivery vehicles. The aim of this study was to describe the interactions of these two prevalent pathogens with the TiO2 NPs. METHODS AND RESULTS: Chlamydia trachomatis and HSV-2 were treated with nonactivated TiO2 NPs, silver NPs and silver decorated TiO2 NPs before infection of HeLa and Vero cells. Their intracellular growth was monitored by quantitative PCR. Unexpectedly, the TiO2 NPs (100 µg ml-1 ) increased the growth of C. trachomatis by approximately fourfold, while the HSV-2 replication was not affected. Addition of TiO2 to silver NPs decreased their antimicrobial activity against C. trachomatis up to 27·92-fold. CONCLUSION: In summary, nonactivated TiO2 NPs could increase the replication of C. trachomatis and decrease the antimicrobial activity of silver NPs. SIGNIFICANCE AND IMPACT OF THE STUDY: The food industry or drug delivery use of TiO2 NPs could enhance the growth of certain intracellular pathogens and potentially worsen disease symptoms, a feature that should be further investigated.

Impact of antiseptics on Chlamydia trachomatis growth.

UNLABELLED: Bacterial vaginosis is a frequent dysbiosis, where the normal lactobacillus-dominated flora is replaced by an anaerob/aerob polymicrobial flora. Bacterial vaginosis increases the risk of acquiring sexually transmitted infections (STI) including the most frequent Chlamydia trachomatis infections. Intravaginal antiseptics are part of the bacterial vaginosis treatment, and ideally they should also inhibit the bacterial vaginosis-related STI. Therefore, we tested the antichlamydial activity of four antiseptics: iodine aqueous solution, povidone-iodine, chlorhexidine and borax. First, we measured the impact of antiseptics on the viability of the HeLa cervical epithelial cells, and calculated the maximum nontoxic concentrations. Next, we infected the cells with C. trachomatis preincubated for 1 h with the particular antiseptic. The chlamydial growth was measured by direct quantitative PCR (qPCR) of the infected cells. The minimal inhibitory concentrations (MIC) of chlorhexidine and povidone-iodine were 3·91 and 97 µg ml(-1) respectively; however, the MIC of chlorhexidine was close to its maximum nontoxic concentration. The iodine aqueous solution and the borax showed no antichlamydial activity. Our in vitro studies showed that chlorhexidine and particularly povidone-iodine are potentially able to limit the bacterial vaginosis-related C. trachomatis infection. SIGNIFICANCE AND IMPACT OF THE STUDY: We measured the antichlamydial effects of various antiseptics. These antiseptics are being used for the treatment of bacterial vaginosis, but their effect on the bacterial vaginosis-related sexually transmitted infections, particularly the most frequent Chlamydia trachomatis (C. trachomatis) infections has not been investigated. We showed that povidone-iodine (Betadine) inhibited the chlamydial growth in concentrations that was not toxic to the epithelial cells. We concluded that due to its additional antichlamydial effect, povidone-iodine could be a preferable antiseptic in bacterial vaginosis treatment.

Chlamydophila pneumoniae and human cytomegalovirus in atherosclerotic carotid plaques--combined presence and possible interactions.

The aim of our study was to investigate the combination of Chlamydophila pneumoniae and human cytomegalovirus (HCMV) as a pathogenic factor in atherosclerosis. Accordingly, we tested by means of PCR and immunohistochemistry the presence of these pathogens in the same atherosclerotic carotid specimen. The histology of the samples and the patients' antibodies against these pathogens were evaluated. Further, we examined the impact of C. pneumoniae and HCMV infection on the gene expression of the human monocytic cell line U937. Six of the 22 samples contained only C. pneumoniae, 4 contained only HCMV, 7 contained both C. pneumoniae DNA and/or antigens of both pathogens, and 5 samples were negative. No correlation was found between the presence of these microbes and either the cellular structure of the plaques, or the serostatus of the patients. The infection of U937 cells with HCMV and especially C. pneumoniae induced inflammation and atherosclerosis-related genes. Furthermore, the doubly-infected cells produced higher levels of the mRNA of pro-platelet basic protein and fatty acid binding protein 4. In conclusion, C. pneumoniae is often present in combination with HCMV in atherosclerotic carotid lesions. The in vitro coinfection model reveals that the doubly-infected monocytes are potent expressors of proatherosclerotic genes, suggesting that this coinfected population may accelerate the process of atherosclerosis.

Chlamydia pneumoniae exacerbates aortic inflammatory foci caused by murine cytomegalovirus infection in normocholesterolemic mice.

Inflammatory foci induced by murine cytomegalovirus infection in normocholesterolemic mice were present temporarily in the aortic wall, but some of these foci developed into advanced lesions that persisted late after infection. The early foci induced by virus infection were significantly exacerbated following a single inoculation with Chlamydia pneumoniae.

Chlamydia pneumoniae in atherosclerotic middle cerebral artery.

BACKGROUND AND PURPOSE: Atherosclerotic middle cerebral arteries are frequent sites of thrombosis, leading to stroke. Previous studies have suggested a role for Chlamydia pneumoniae in the pathogenesis of atherosclerosis. However, the presence of this pathogen in atherosclerotic middle cerebral arteries has heretofore not been documented. In the present study, we analyzed atheromatous plaques from middle cerebral arteries for the presence of C pneumoniae. METHODS: Atherosclerotic middle cerebral arteries from 15 cadavers who died of natural causes and corresponding nonatherosclerotic arteries from 4 otherwise healthy trauma victims were examined. Assays for C pneumoniae DNA were carried out by nested polymerase chain reaction (nPCR) specific for the C pneumoniae ompA gene. The presence of the bacterium was assessed by transmission electron microscopy. RESULTS: Five of the 15 atherosclerotic arterial samples and none of the control tissues were positive for C pneumoniae by nPCR. Particles similar in morphology and size to C pneumoniae elementary bodies were detected by transmission electron microscopy in 4 of the 5 nPCR-positive atherosclerotic samples. CONCLUSIONS: The demonstration of C pneumoniae in atherosclerotic middle cerebral arteries is consistent with the hypothesis that this bacterium is involved in acute and chronic cerebrovascular diseases.

Optimization of DNA immunization against human cytomegalovirus.

The immune responses of mice injected with plasmids VR-gB and VR-gB Delta tm expressing the full-length membrane-anchored, or secreted forms of human cytomegalovirus (HCMV)-glycoprotein B (gB), respectively, and VR-pp65 expressing the HCMV-phosphoprotein 65 (pp65) were analyzed. Pretreatment of mice with the local anesthetic bupivacaine did not enhance antibody production, and IFN-alpha co-expressed with the immunizing plasmids induced a moderate increase in the antibody response. However, antibody response was higher in mice inoculated at three sites in the musculus quadriceps than in mice inoculated at one site with the same dose and in the same muscle. pVR-gB Delta tm induced significantly higher antibody titers than the construct expressing the membrane-anchored form of gB, and priming with pVR-gB Delta tm followed by boosting with the gB subunit resulted in high-titer antibody responses. Immunization with VR-pp65 induced dose-dependent CTL responses in about 50% of the mice at a dose of 50 microg. Co-expression of IFN-alpha did not affect the number of responding mice. These findings might be important for optimization of humoral and cellular immune responses to HCMV after DNA vaccination.

Independent and joint effects of antibodies to human heat-shock protein 60 and Chlamydia pneumoniae infection in the development of coronary atherosclerosis.

BACKGROUND: Studies have suggested that the prevalence of antibodies against heat-shock proteins (HSPs), Chlamydia pneumoniae (CPN), and cytomegalovirus (CMV) is associated with coronary artery disease (CAD), but the independent or joint effects of human (h) HSP60 antibodies and these pathogens in patients have not been fully elucidated. METHODS AND RESULTS: A total of 405 subjects (276 patients with CAD and 129 control individuals) were tested for serum antibodies to hHSP60, CPN, and CMV immediate-early-1 (IE1) antigens. Patients were also assessed for serum cholesterol, triglyceride levels, and smoking habit. Significantly elevated levels of antibodies to hHSP60 and CPN but not to CMV-IE1 antigens were documented in CAD patients. Multiple logistic regression analysis and subanalyses of selected subjects showed that these associations were independent of age, sex, smoking, and serum lipid levels. Antibodies to hHSP60 and CPN did not correlate quantitatively; however, the relative risk of disease development was substantially increased in subjects with high antibody levels to both hHSP60 and CPN:, reaching an odds ratio of 82.0 (95% CI 10.6 to 625.0). CONCLUSIONS: High levels of antibodies to hHSP60 and CPN: are independent risk factors for coronary atherosclerosis, but their simultaneous presence substantially increases the risk for disease development.

Chronic infections and atherosclerosis.

The inability of traditional risk factors such as hypercholesterolemia, hypertension, and smoking to explain the incidence of atherosclerosis (AT) in about 50% of the cases prompted a search for additional putative risk factors involved in the development of the disease. Infectious agents have long been suspected to initiate/contribute to the process of AT. It has also been suggested that inflammation, either related to infectious agents or independent from infection, may mediate the atherogenic process [1, 2].