M. Del Piano

Chlamydia pneumoniae and atherosclerosis: current state and future prospectives.

Chlamydia pneumoniae, an intracellular bacterial pathogen, is known as a leading cause of human respiratory tract infections worldwide. Over the last decade, several reports in the literature have suggested that infection with C. pneumoniae may contribute to the pathogenesis of atherosclerosis. In order to play a causative role in chronic disease, C. pneumoniae would need to persist within infected tissue for extended periods of time, thereby stimulating a chronic inflammatory response. C. pneumoniae has been shown to disseminate systemically from the lungs through infected peripheral blood mononuclear cells and to localize in arteries where it may infect endothelial cells, vascular smooth muscle cells, monocytes/macrophages and promote inflammatory atherogenous process. The involvement of C. pneumoniae in atherosclerosis was investigated by seroepidemiological and pathological studies, in vivo and in vitro studies, and in clinical antibiotic treatment trials. This review will provide an update on the role of C. pneumoniae in atherosclerosis focusing on the recent insights and suggesting areas for future research.

Chlamydia pneumoniae induces T cell apoptosis through glutathione redox imbalance and secretion of TNF-α

Chlamydia pneumoniae persistent infection has been implicated in the pathogenesis of several chronic inflammatory diseases including atherosclerosis, and we hypothesized that modulation of the apoptosis of macrophages and/or T cells by C. pneumoniae infection may contribute to the development of such diseases. We therefore evaluated apoptosis, cytokine response, and redox status in human primary T cells and macrophages infected with C. pneumoniae. In addition, co-cultures of T cells and macrophages infected with C. pneumoniae were also carried out. Apoptosis, and levels of glutathione (GSH), glutathione disulfide (GSSG), and tumour necrosis factor (TNF)-α were measured by flow cytometry, high performance liquid chromatography and enzyme-linked immunosorbent assay. C. pneumoniae induced apoptosis in T cells as well as in co-cultures of T cells and infected macrophages by marked decrease in GSH/GSSG ratio and increased production of TNF-α, respectively. The results demonstrate that interaction of C. pneumoniae with T cells and/or macrophages characterized by interference with redox status, and secretion of tumour necrosis factor TNF-α culminates in the induction of T cell apoptosis and survival of infected macrophages. In conclusion, the inappropriate T cell response against C. pneumoniae and survival of infected macrophages could explain the persistence of this intracellular obligate pathogen in the host-organism; it may contribute to the development of chronic inflammatory diseases, although further studies are needed to clarify such a complex mechanism.

Detection of four Borrelia burgdorferi genospecies and first report of human granulocytic ehrlichiosis agent in Ixodes ricinus ticks collected in central Italy

The presence of Borrelia burgdorferi s.l. and of Ehrlichia phagocytophila group was sought by PCR in Ixodes ricinus collected in a protected area of central Italy. Nymphs (n = 1475, gathered in 295 pools of 5 nymphs each) and adult ticks (n = 28) were examined. B. burgdorferi s.l. was detected in 13.8% of the nymph pools; of these, 63.4% were infected by B. valaisiana, 26.8% by B. afzelii, 7.3% by B. garinii, and 2.5% by B. burgdorferi s.s. Only a single adult male tick proved to host B. afzelii. The agent of human granulocytic ehrlichiosis (HGE) was detected in 2.7% of the nymph pools. Two HGE agent-positive nymph pools were also found to be positive for B. garinii and for B. afzelii, respectively. This is the first report from central Italy of the finding of the HGE agent in ticks.

Prevalence of IgG Antibodies against Borrelia Burgdorferi S.L. and Ehrlichia Phagocytophila in Sera of Patients Presenting Symptoms of Lyme Disease in a Central Region of Italy

The aim of this study was to evaluate the prevalence (seroprevalence) of antibodies against Borrelia burgdorferi and Ehrlichia phagocytophila among patients resident in Lazio, a region of central Italy. Of a sample of 1,050 patients, which presented clinical manifestations related to Lyme disease, 34 (3.2%) were Borrelia-seropositive (Lyme index value ≥ 1.2). The sera of 25 out of the 34 patients that were Borrelia-positive were also analysed for the presence of antibodies against E. phagocytophila and 3 (12%) were found Ehrlichia-positive (titres >1:64). No Ehrlichia-positive samples were found among sera of 250 Borrelia-negative patients. Since both B. burgdorferi s.l. and Ehrlichia species share the same tick vector (Ixodes ricinus), our results indicate that concurrent transmission of these microbial pathogens might have been occurred among the patients included in this study.

Chlamydia pneumoniae and chronic diseases with a great impact on public health.

Chlamydia pneumoniae is recognised as a common cause of respiratory tract infections and has recently been implicated in several extrapulmonary chronic diseases, with great impact on public health, such as atherosclerosis, multiple sclerosis and Alzheimers disease. The involvement of C. pneumoniae in such diseases may be correlated to characteristic features of this pathogen, including intracellular growth and ability to induce persistent forms. C. pneumoniae persistent forms are inherently more suited to evade the host immune response and are more difficult to eradicate by antibiotics. Our preliminary experimental findings show that interaction of C. pneumoniae with macrophages and/or T cells characterized by interference with TNF-α production, and redox state, culminates in the induction of T cell apoptosis and survival of infected macrophages. Based on our evidence, the poor cooperation between T cells and macrophages could lead to an inappropriate immune response against C. pneumoniae that may therefore promote the development of extrapulmonary chronic diseases.

Study on tissue concentrations of antibiotics bacampicillin in gingiva and maxillary bones

21 patients, whose age ranged from 17 to 60 years and who had not been previously treated with antibiotics or other drugs, received bacampicillin as a perioperative prophylaxis for minor operations in the oral cavity. Four oral doses of bacampicillin were administered: each dose of 800 mg every 12 h, and the last dose was administered 2 h before surgery. To assess bacampicillin serum concentrations two blood samples were collected from each patient: the first sample was obtained 1 h before surgery and the second one during surgery. Together with the second blood sample, small quantities of gingiva and bone were obtained from each patient to also assess the antibiotic concentrations in these tissues (microbiological method). The results show that bacampicillin reaches high concentrations in both the blood and tissues studied by us, and that a direct correspondence exists between blood and gingival and bone tissue concentrations. Furthermore, it should be noted that no postoperative infections developed in our patients. These results lead to the conclusion that bacampicillin appears to be a suitable drug in the therapy of dental infections.

No evidence of involvement of Chlamydia pneumoniae in lung cancer by means of quantitative real-time polymerase chain reaction.

Chlamydia pneumoniae, an obligate intracellular pathogen, is well-known as etiological agent of acute respiratory infections; the repeated or prolonged exposure to chlamydial antigens may promote the persistence of C. pneumoniae in the respiratory tract leading to chronic diseases, such as chronic obstructive pulmonary disease and asthma. The predilection of C. pneumoniae to cause respiratory tract infections combined with its persistent nature suggest that it might play a role in lung cancer. The aim of our study is to evaluate the involvement of C. pneumoniae in pathogenesis of lung cancer. We therefore investigated the presence of C. pneumoniae DNA in tumor lung tissues by using real-time PCR assay. Simultaneously, tumor and healthy tissues from the same patient with primary carcinoma lung were analyzed. C. pneumoniae DNA was not detected in a single lung tumor tissue by means of an highly sensitive, and specific real-time PCR assay based on FRET hybridization probes. In conclusion, this study does not support the involvement of C. pneumoniae in the pathogenesis of lung cancer, suggesting that further investigations are needed to clarify other potential causative factors for the development of this malignancy.

Lyme Borreliosis Infection in Europe

Lyme borreliosis is the most common tick-borne disease in the United States and Europe. It is caused by spirochetes of the Borrelia burgdorferi species complex which are transmitted by ticks of the genus Ixodes. This paper presents a review of the studies published about Lyme borreliosis in Europe and in Italy. Seroepidemiologic studies have been conducted in various European countries concerning patients, groups at risk and general population. The distribution of LB in Europe is very variable and the risk is associated with occupational and recreational activities in forested areas and with residence in rural area. Taking the limitations of seroprevalence methods into account, it is evident that the prevalence of Lyme borreliosis varies considerably in different European countries, with an overall increasing prevalence from west to east in central-eastern Europe, a gradient of decreasing incidence in Spain and Greece and from north to south in Italy.

Asbestos hazards in the city of Rome, Italy

A review is made of asbestos as a health hazard, and attention is drawn to possible dangers due to exposure to asbestos in the city of Rome in and outside the work place. The exposure to asbestos of workers of the ATAC company (the public concern of urban passenger transport of Rome) is examined. This is particularly dangerous for workers who repair equipment with asbestos components, such as brake linings. Exposure to asbestos may also occur in inhabitants who live and work close to where asbestos fibres collect. The study evaluates the contamination of asbestos fibres in both work and urban environment among people directly or indirectly exposed to this pollutant.

Detection of different Borrelia burgdorferi genospecies in serum of people with different occupational risks: short report.

This study is aimed at applying a previously described PCR-based method to detect B. burgdorferi sensu lato and different Borrelia genospecies in total DNA preparations of serum samples collected from people with different occupational risks for tick bite and with serological evidence of borreliosis. Among the seropositive samples, the PCR for B. burgdorferi confirmed the positivity in 65% of the forestry workers and in 60% of the subjects living in the same area. None of the seronegative subjects belonging to the control group showed the presence of B. burgdorferi sensu lato DNA. Results on genospecies distribution show that B. afzelii was the predominant species, followed by B. garinii and finally by B. valaisiana.