Anti-Biofilm Activity of Oleacein and Oleocanthal from Extra-Virgin Olive Oil toward Pseudomonas aeruginosa

New antimicrobial molecules effective against Pseudomonas aeruginosa, known as an antibiotic-resistant "high-priority pathogen", are urgently required because of its ability to develop biofilms related to healthcare-acquired infections. In this study, for the first time, the anti-biofilm and anti-virulence activities of a polyphenolic extract of extra-virgin olive oil as well as purified oleocanthal and oleacein, toward P. aeruginosa clinical isolates were investigated. The main result of our study was the anti-virulence activity of the mixture of oleacein and oleocanthal toward multidrug-resistant and intermediately resistant strains of P. aeruginosa isolated from patients with ventilator-associated pneumonia or surgical site infection. Specifically, the mixture of oleacein (2.5 mM)/oleocanthal (2.5 mM) significantly inhibited biofilm formation, alginate and pyocyanin production, and motility in both P. aeruginosa strains (p < 0.05); scanning electron microscopy analysis further evidenced its ability to inhibit bacterial cell adhesion as well as the production of the extracellular matrix. In conclusion, our results suggest the potential application of the oleacein/oleocanthal mixture in the management of healthcare-associated P. aeruginosa infections, particularly in the era of increasing antimicrobial resistance.

Current progresses and challenges for microbiome research in human health: a perspective

It is becoming increasingly clear that the human microbiota, also known as "the hidden organ", possesses a pivotal role in numerous processes involved in maintaining the physiological functions of the host, such as nutrient extraction, biosynthesis of bioactive molecules, interplay with the immune, endocrine, and nervous systems, as well as resistance to the colonization of potential invading pathogens. In the last decade, the development of metagenomic approaches based on the sequencing of the bacterial 16s rRNA gene via Next Generation Sequencing, followed by whole genome sequencing via third generation sequencing technologies, has been one of the great advances in molecular biology, allowing a better profiling of the human microbiota composition and, hence, a deeper understanding of the importance of microbiota in the etiopathogenesis of different pathologies. In this scenario, it is of the utmost importance to comprehensively characterize the human microbiota in relation to disease pathogenesis, in order to develop novel potential treatment or preventive strategies by manipulating the microbiota. Therefore, this perspective will focus on the progress, challenges, and promises of the current and future technological approaches for microbiome profiling and analysis.

Editorial for the Special Issue "Antibacterial Activity of Drug-Resistant Strains"

Antimicrobial resistance is an urgent global public health threat, as approximately 700,000 deaths annually can be attributed to antibiotic-resistant bacterial infections, and this figure is expected to reach 10 million deaths/year by 2050, a number that greatly exceeds the number of deaths resulting from cancer [...].

Olea europaea L-derived secoiridoids: Beneficial health effects and potential therapeutic approaches

Over the years, health challenges have become increasingly complex and global and, at the beginning of the 21st century, chronic diseases, including cardiovascular, neurological, and chronic respiratory diseases, as well as cancer and diabetes, have been identified by World Health Organization as one of the biggest threats to human health. Recently, antimicrobial resistance has also emerged as a growing problem of public health for the management of infectious diseases. In this scenario, the exploration of natural products as supplementation or alternative therapeutic options is acquiring great importance, and, among them, the olive tree, Olea europaea L, specifically leaves, fruits, and oil, has been increasingly investigated for its health promoting properties. Traditionally, these properties have been largely attributed to the high concentration of monounsaturated fatty acids, although, in recent years, beneficial effects have also been associated to other components, particularly polyphenols. Among them, the most interesting group is represented by Olea europaea L secoiridoids, comprising oleuropein, oleocanthal, oleacein, and ligstroside, which display anti-inflammatory, antioxidant, cardioprotective, neuroprotective and anticancer activities. This review provides an overview of the multiple health beneficial effects, the molecular mechanisms, and the potential applications of secoiridoids from Olea europaea L.

Interferon-ε as potential inhibitor of Chlamydia trachomatis infection

Chlamydia trachomatis, the main cause of bacterial sexually transmitted diseases, is responsible for severe reproductive sequelae. Amongst all the cytokines involved in host immunity towards this pathogen, IFN-ε has recently acquired importance for its potential contribution to the female reproductive tract innate defenses. Herein, our study aimed to explore, for the first time, the activity of IFN-ε toward C. trachomatis in an in vitro infection model, by testing its effects on the different phases of chlamydial developmental cycle, as well as on the ultrastructural characteristics of chlamydial inclusions, via transmission electron microscopy. Main result is the capability of IFN-ε to alter C. trachomatis growth, as suggested by reduced infectious progenies, as well as a patchy distribution of bacteria and altered morphology of reticulate bodies within inclusions. In conclusion, our results suggest that IFN-ε could play a role in the innate and adaptive immune defenses against C. trachomatis; in the future, it will be needed to investigate its activity on an infection model more closely resembling the physiological environment of the female genital tract.

Extra Virgin Olive Oil-Based Formulations: A "Green" Strategy against Chlamydia trachomatis

In recent decades, antibiotic misuse has emerged as an important risk factor for the appearance of multi-drug-resistant bacteria, and, recently, antimicrobial resistance has also been described in Chlamydia trachomatis as the leading cause of bacterial sexually transmitted diseases worldwide. Herein, we investigated, for the first time, the antibacterial activity against C. trachomatis of a polyphenolic extract of extra virgin olive oil (EVOO), alongside purified oleocanthal and oleacein, two of its main components, in natural deep eutectic solvent (NaDES), a biocompatible solvent. The anti-chlamydial activity of olive-oil polyphenols (OOPs) was tested in the different phases of chlamydial developmental cycle by using an in vitro infection model. Transmission and scanning electron microscopy analysis were performed for investigating potential alterations of adhesion and invasion, as well as morphology, of chlamydial elementary bodies (EBs) to host cells. The main result of our study is the anti-bacterial activity of OOPs towards C. trachomatis EBs down to a total polyphenol concentration of 1.7 μg/mL, as shown by a statistically significant decrease (93.53%) of the total number of chlamydial-inclusion-forming units (p < 0.0001). Transmission and scanning electron microscopy analysis supported its anti-chlamydial effect, suggesting that OOP might damage the chlamydial outer layers, impairing their structural integrity and hindering EB capability to infect the host cell. In conclusion, OOPs may represent an interesting alternative therapeutic option toward C. trachomatis, although further studies are necessary for exploring its clinical applications.

SARS-CoV-2 Infection in Pregnancy: Clues and Proof of Adverse Outcomes

BACKGROUND

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) represents one of the most threatening viral infections in the last decade. Amongst susceptible individuals, infected pregnant women might be predisposed to severe complications. Despite the extensive interest in SARS-CoV-2 research, the clinical course of maternal infection, the vertical transmission and the neonatal outcomes have not been completely understood yet. The aim of our study was to investigate the association between SARS-CoV-2 infection, obstetric outcomes and vertical transmission.

METHODS

A prospective observational study was performed, enrolling unvaccinated pregnant patients positive for SARS-CoV-2 (cases) and matched with uninfected pregnant women (controls). Maternal and neonatal nasopharyngeal swabs, maternal and cord blood, amniotic fluid and placenta tissue samples were collected; blood samples were tested for anti-S and anti-N antibodies, and histologic examination of placental tissues was performed.

RESULTS

The cases showed a significant association with the development of some obstetric complications, such as intrauterine growth restriction and pregnancy-associated hypothyroidism and diabetes, as compared to controls; their newborns were more likely to have a low birth weight and an arterial umbilical pH less than 7. The viral genome was detected in maternal and cord blood and placental samples in six cases.

CONCLUSIONS

Pregnant women positive for SARS-CoV-2 infection are more likely to develop severe obstetric outcomes; their newborns could have a low birth weight and arterial pH. Vertical transmission seems a rare event, and further investigation is strongly needed.

In-Silico Functional Metabolic Pathways Associated to Chlamydia trachomatis Genital Infection

The advent of high-throughput technologies, such as 16s rDNA sequencing, has significantly contributed to expanding our knowledge of the microbiota composition of the genital tract during infections such as Chlamydia trachomatis. The growing body of metagenomic data can be further exploited to provide a functional characterization of microbial communities via several powerful computational approaches. Therefore, in this study, we investigated the predicted metabolic pathways of the cervicovaginal microbiota associated with C. trachomatis genital infection in relation to the different Community State Types (CSTs), via PICRUSt2 analysis. Our results showed a more rich and diverse mix of predicted metabolic pathways in women with a CST-IV microbiota as compared to all the other CSTs, independently from infection status. C. trachomatis genital infection further modified the metabolic profiles in women with a CST-IV microbiota and was characterized by increased prevalence of the pathways for the biosynthesis of precursor metabolites and energy, biogenic amino-acids, nucleotides, and tetrahydrofolate. Overall, predicted metabolic pathways might represent the starting point for more precisely designed future metabolomic studies, aiming to investigate the actual metabolic pathways characterizing C. trachomatis genital infection in the cervicovaginal microenvironment.

SARS-CoV-2 vertical transmission in a twin-pregnant woman: a case report

SARS-CoV-2 has affected millions of people around the world in recent years. Among susceptible patients, pregnant women seem to be prone to serious complications. The possibility of SARS-CoV-2 vertical transmission represents one of the most debated topics in the literature, providing inconclusive results. We present a case of a confirmed vertical transmission in a monochorial diamniotic twin pregnancy complicated by a selective intrauterine growth restriction and gestational diabetes mellitus. The analysis of different biological specimens identifies the presence of the SARS-CoV-2 genome in the umbilical cord blood of both twins, and the placental histologic examination confirmed indirect signs of viral infection, supporting the hypothesis that a transplacental infection can occur. Despite the devastating impact that SARS-CoV-2 has worldwide, neonatal infections have been infrequently reported, but they can occur under certain biologic conditions. Deep knowledge of the biological mechanisms underlying the risk of SARS-CoV-2 vertical transmission might be useful to understand the pathophysiological bases and the possible long-term implication of a mother-to-child vertical transmission.

Impact of Air Pollution on the Composition and Diversity of Human Gut Microbiota in General and Vulnerable Populations: A Systematic Review

Recently, growing attention has focused on the impact of air pollution on gut microbiota as a possible mechanism by which air pollutant exposure increased the risk for chronic diseases, as evidenced by in vivo studies demonstrating important exposure-induced alterations in the diversity and relative abundance of gut bacterial taxa. This systematic review provides updated state-of-art findings of studies examining the impact of air pollution on the human gut microbiota. Databases PubMed, Scopus, and Web of Science were searched with the following strategy: "air poll*" AND "gut micro*" OR "intestinal micro*"; moreover, a total of 10 studies were included. Overall, there is the evidence that short-term and long-term exposure to air pollutants have the potential to alter the composition and diversity of gut microbiota; some studies also correlated air pollution exposure to adverse health effects (impaired fasting glucose, adverse pregnancy outcomes, and asthma attacks) via alterations in the composition and/or function of the gut microbiota. However, the evidence on this topic is still scarce, and large cohort studies are needed globally.

What is the Hidden Biological Mechanism Underlying the Possible SARS-CoV-2 Vertical Transmission? A Mini Review

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS- CoV-2) represents an emerging infection that is spreading around the world. Among susceptible patients, pregnant women are more likely to develop serious complications and negative obstetric outcomes. Vertical transmission constitutes a debating issue which has not been completely understood. This review aims at describing the currently available evidence on SARS-CoV2 vertical transmission. We carried out a computerized literature search in the Cochrane Library, PubMed, Scopus and Web of Science, selecting the most relevant studies on vertical transmission from the outbreak onset until February 2022. The analysis of the available literature identifies the presence of SARS-CoV2 genome in different biological specimens, confirming the hypothesis that a transplacental infection can occur. In spite of the high number of infected people around the world, mother-to-child infections have been infrequently reported but it can be observed under certain biologic conditions. A deep knowledge of the underlying mechanisms of SARS-CoV2 vertical transmission is of paramount importance for planning an adequate management for the affected mothers and newborns.

Extra Virgin Olive Oil-Based Green Formulations With Promising Antimicrobial Activity Against Drug-Resistant Isolates

Extra virgin olive oil (EVOO) from Olea europaea L. drupes, a cornerstone in the Mediterranean diet, is well known for its nutritional and health properties, especially for prevention of cardiovascular diseases and metabolic disorders. Traditionally, beneficial health effects have been largely attributed to the high concentration of monounsaturated fatty acids, and in recent years, these have also been related to other components including oleacein and oleocanthal. Here, we evaluated, for the first time, the antimicrobial activity of different green extra virgin olive oil-based formulations in natural deep eutectic solvents (NaDESs) emerging as powerful and biocompatible solvents. Specifically, the antimicrobial activity of the EVOO extract, as well as purified oleocanthal and oleacein in two NaDESs (choline/glycerol and choline/propylene glycol), against several drug-resistant clinical isolates and standard microbial strains has been evaluated. The main result was the inhibitory activity of the EVOO extract in choline/glycerol as well as oleacein in choline/propylene glycol toward drug-resistant Gram-positive and -negative strains. Specifically, the EVOO extract in choline/glycerol showed the highest antibacterial activity against several clinical strains of Staphylococcus aureus, whereas oleacein in choline/propylene glycol was the most effective toward various clinical strains of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In addition, all the formulations tested were effective against Candida spp. In conclusion, our results suggest EVOO-based formulations in NaDESs as an interesting strategy that may help in reducing the risk of development of drug resistance. Under this perspective, the usage of NaDESs for the preparation of new antimicrobial formulations may represent a promising approach.

The Potential Role of Hypochlorhydria in the Development of Duodenal Dysbiosis: A Preliminary Report

In recent years, the role of gastric and duodenal microbiota has acquired increasing importance in the homeostasis of the host, although, to date, most evidence concern the faecal microbiota. Indeed, the gastric, and duodenal microbiota are challenging to study, due to gastric acid, bile, digestive enzymes, and rapid transit time. Specifically, the gastric acid environment may influence their bacterial composition since the acid barrier protects against orally ingested microorganisms and leads to their inactivation before reaching the intestine. The aim of this study was to assess a correlation between intragastric pH and gastric as well as intestinal microbiota of patients with histologic gastric alterations. pH was measured in the gastric juice and the bacterial composition in gastric and duodenal biopsies and faecal samples, was investigated via 16s rRNA gene sequencing. The main result is the direct correlation of duodenal microbiota biodiversity, via alpha diversity measures, with intragastric pH values. In particular, patients with hypochlorhydria showed increased duodenal microbiota biodiversity, higher intragastric pH values being prevalent in patients with chronic atrophic gastritis. Lastly, the latter was also strongly associated to the presence of oral bacteria, like Rothia mucilaginosa, Streptococcus salivarius and Granulicatella adiacens, in the duodenal microbiota. In conclusions, our results suggest a low-acid gastric environment as a contributive factor for duodenal dysbiosis, potentially leading to the development of pathological conditions of the gastrointestinal tract.

Towards a Deeper Understanding of Chlamydia trachomatis Pathogenetic Mechanisms: Editorial to the Special Issue "Chlamydia trachomatis Pathogenicity and Disease"

Chlamydia trachomatis, an obligate intracellular Gram-negative bacterium, is characterized by a wide range of different serotypes responsible for several local or systemic human diseases, including genital tract manifestations (D-K), trachoma (A-C), and lymphogranuloma venereum (L1-3) [...].

In Vitro Modelling of Chlamydia trachomatis Infection in the Etiopathogenesis of Male Infertility and Reactive Arthritis

Chlamydia trachomatis is an obligate, intracellular bacterium responsible for a range of diseases of public health importance, since C. trachomatis infection is often asymptomatic and, hence, untreated, leading to chronic complications, including prostatitis, infertility, and reactive arthritis. The ample spectrum of diseases caused by C. trachomatis infection is reflected in its ability to infect and multiply within a wide range of different cell types. Cervical epithelial cells, to date, have been the most studied cellular infection model, highlighting the peculiar features of the host-cell inflammatory and immune responses to the infection. Herein, we provide the up-to-date evidence on the interaction between C. trachomatis and human prostate epithelial, Sertoli and synovial cells.

Oxidative Stress and Inflammation in SARS-CoV-2- and Chlamydia pneumoniae-Associated Cardiovascular Diseases

Throughout the years, a growing number of studies have provided evidence that oxidative stress and inflammation may be involved in the pathogenesis of infectious agent-related cardiovascular diseases. Amongst the numerous respiratory pathogens, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus responsible for the global ongoing pandemic, and Chlamydia pneumoniae, a widely known intracellular obligate bacteria, seem to have an essential role in promoting reactive oxygen species and cytokine production. The present review highlights the common oxidative and inflammatory molecular pathways underlying the cardiovascular diseases associated with SARS-CoV-2 or C. pneumoniae infections. The main therapeutic and preventive approaches using natural antioxidant compounds will be also discussed.

In-cell western assay as a high-throughput approach for Chlamydia trachomatis quantification and susceptibility testing to antimicrobials

Chlamydia trachomatis, the leading cause of bacterial sexually transmitted diseases in developed countries, with around 127 million new cases per year, is mainly responsible for urethritis and cervicitis in women, and urethritis and epididymitis in men. Most C. trachomatis infections remain asymptomatic (>50%) and, hence, untreated, leading to severe reproductive complications in both women and men, like infertility. Therefore, the detection of C. trachomatis as well as the antimicrobial susceptibility testing becomes a priority, and, along the years, several methods have been recommended, like cell culture and direct immunofluorescence (DFA) on cell cultures. Herein, we described the application of In-Cell Western assay (ICW) via Odyssey CLx as a fast, more accessible, and high-throughput platform for the quantification of C. trachomatis and the screening of anti-chlamydial drugs. As a first step, we set up a standard curve by infecting cell monolayers with 2-fold serial dilutions of C. trachomatis Elementary Body (EB) suspension. Then, different unknown C. trachomatis EB suspensions were quantified and the chlamydial susceptibility testing to erythromycin was performed, using the DFA as comparison. Our results showed a very high concordance between these two assays, as evidenced by the enumeration of chlamydial IFUs as well as the determination of erythromycin Minimum Inhibitory Concentration (MIC). In conclusion, the ICW assay may be a promising candidate as an accurate and accessible methodology for C. trachomatis antimicrobial susceptibility testing.

Chlamydia trachomatis elicits TLR3 expression but disrupts the inflammatory signaling down-modulating NFκB and IRF3 transcription factors in human Sertoli cells

Chlamydia trachomatis, the leading cause of bacterial sexually transmitted diseases worldwide, can disseminate and localize to the upper genital tract impairing reproductive function. Specifically, ascending C. trachomatis genital infection has been demonstrated to cause epididymitis or epididymo-orchitis, well-known risk factors for male infertility. C. trachomatis possesses the ability to infect primary human Sertoli cells, key elements for the spermatogenetic process and the immune protection of germ cells. Therefore, herein, we investigated the innate immune response in Sertoli cells following C. trachomatis infection, as well as its indirect effects on human spermatozoa. Specifically, we evaluated C. trachomatis mediated induction of Toll-like Receptors (TLR) 2, 3 and 4 as well as of downstream intracellular signaling molecules (NFκB and IRF3) and the levels of the related inflammatory mediators (IL-1α, IL-6, IFN-α, IFN-β and IFN-γ), in an in vitro infection model of primary human Sertoli cells. The main result of our study shows that C. trachomatis induced TLR3-mediated recognition in human Sertoli cells, accompanied by the down-modulation of NFκB and IRF3-dependent signaling pathways followed by no production of pro-inflammatory cytokines. In conclusion, our findings suggest that C. trachomatis can disrupt the innate immune response in Sertoli cells and evade intracellular killing, potentially giving rise to a long-term infection that may exert negative effects on the male reproductive system.

Therapeutic potential of resveratrol against emerging respiratory viral infections

Resveratrol has been widely studied for its therapeutic potential due to its antioxidant, anti-inflammatory and anti-microbial properties. In particular, resveratrol has shown promising antiviral activity against numerous viruses responsible for severe respiratory infections. Amongst these, influenza virus, respiratory syncytial virus and the emerging SARS-cov-2 are known to cause pneumonia, acute respiratory distress syndrome or multi-organ failure, especially, in vulnerable individuals like immunocompromised patients or the elderly, leading to a considerable economic burden worldwide. In this context, resveratrol may have potential value for its anti-inflammatory activity, since most of the severe virus-associated complications are related to the overactivation of the host-immune response, leading to lung damage. Herein, we present an overview of the antiviral activity and potential mechanisms of resveratrol against the respiratory tract viruses considered as a public threat for their rapid transmission and high morbidity and mortality in the general population.

Interferon-γ Possesses Anti-Microbial and Immunomodulatory Activity on a Chlamydia Trachomatis Infection Model of Primary Human Synovial Fibroblasts

Chlamydia trachomatis, an obligate intracellular pathogen, is the most common cause of bacterial sexually transmitted diseases, and it is potentially responsible for severe chronic sequelae, such as reactive arthritis. To date, details of the mechanisms by which Chlamydiae induce innate antimicrobial pathways in synovial fibroblasts, are not well characterized; therefore, herein, we investigated the effects of interferon (IFN)α, IFNβ, and IFNγ on the infection, and replication phases of the C. trachomatis developmental cycle, as well as on the induction of pattern recognition receptors (PRRs) and IFN-related pathways. To do so, we set up an in vitro chlamydial-infection model of primary human synovial cells treated with IFNs before or after the infection. We then determined the number of chlamydial inclusion forming units and inclusion size, as well as the expression of toll like receptor (TLR)2, TLR3, TLR4, cyclic GMP-AMP synthase (cGAS), stimulator of IFN gene (STING), IRF9, ISG56, and GBP1. The main result of our study is the significant inhibition of C. trachomatis infection and replication in human synovial cells following the treatment with IFNγ, whereas IFN-I proved to be ineffective. Furthermore, IFNγ greatly upregulated all the PRRs and ISGs examined. In conclusion, IFNγ exhibited a potent anti-Chlamydia activity in human synovial cells as well as the ability to induce a strong increase of innate immune pathways.

A simple, fast and reliable scan-based technique as a novel approach to quantify intracellular bacteria

Background

Quantification of intracellular bacteria is fundamental in many areas of cellular and clinical microbiology to study acute and chronic infections. Therefore, rapid, accurate and low-cost methods represent valuable tools in determining bacterial ability to persist and proliferate within eukaryotic cells.

Results

Herein, we present the first application of the immunofluorescence In-Cell Western (ICW) assay aimed at quantifying intracellular bacteria in in vitro infection models. The performance of this new approach was evaluated in cell culture infection models using three microorganisms with different lifestyles. Two facultative intracellular bacteria, the fast-growing Shigella flexneri and a persistent strain of Escherichia coli, as well as the obligate intracellular bacterium Chlamydia trachomatis were chosen as bacterial models. The ICW assay was performed in parallel with conventional quantification methods, i.e. colony forming units (CFUs) and inclusion forming units (IFUs). The fluorescence signal intensity values from the ICW assay were highly correlated to CFU/IFUs counting and showed coefficients of determination (R²), ranging from 0,92 to 0,99.

Conclusions

The ICW assay offers several advantages including sensitivity, reproducibility, high speed, operator-independent data acquisition and overtime stability of fluorescence signals. All these features, together with the simplicity in performance, make this assay particularly suitable for high-throughput screening and diagnostic approaches.

Chlamydia trachomatis and Chlamydia pneumoniae Interaction with the Host: Latest Advances and Future Prospective

Research in Chlamydia trachomatis and Chlamydia pneumoniae has gained new traction due to recent advances in molecular biology, namely the widespread use of the metagenomic analysis and the development of a stable genomic transformation system, resulting in a better understanding of Chlamydia pathogenesis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is responsible of cervicitis and urethritis, and C. pneumoniae, a widespread respiratory pathogen, has long been associated with several chronic inflammatory diseases with great impact on public health. The present review summarizes the current evidence regarding the complex interplay between C. trachomatis and host defense factors in the genital micro-environment as well as the key findings in chronic inflammatory diseases associated to C. pneumoniae.

Chlamydia Pneumoniae in Asymptomatic Carotid Atherosclerosis

We evaluated, in 415 patients with asymptomatic carotid atherosclerosis: (i) the prevalence of C. pneumoniae DNA in atherosclerotic carotid plaques and peripheral blood mononuclear cells (PBMC); (ii) the distribution of C. pneumoniae in atherosclerotic carotid plaques and PBMC from the same patients; (iii) the correlation between circulating anti-chlamydial antibodies and the presence of C. pneumoniae DNA. Overall, 160 atherosclerotic carotid plaques and 174 PBMC specimens from patients with asymptomatic carotid atherosclerosis were examined by ompA nested touchdown PCR for presence of C. pneumoniae. In addition, C. pneumoniae DNA was detected in 81 specimens of atherosclerotic carotid plaque and PBMC obtained from the same patients. C. pneumoniae DNA was found in 36.9% of atherosclerotic carotid plaques and in 40.2% of PBMC specimens examined (P=NS). With regard to 81 patients, C. pneumoniae DNA was detected in 27.2% of atherosclerotic carotid plaques and in 44.4% of PBMC specimens (P=0.05). In 18 patients, the presence of C. pneumoniae DNA in PBMC specimens and atherosclerotic carotid plaques coincided (P=0.005). No statistically significant association was found between anti-C pneumoniae antibodies (IgG and IgA) and positive PCR results. In conclusion, our results suggest that the detection of C. pneumoniae DNA in PBMC specimens seems to be a first-choice method to identify the patients at risk for endovascular chlamydial infection.

Lactobacilli-lactoferrin interplay in Chlamydia trachomatis infection

In the cervicovaginal microenvironment, lactobacilli are known to protect against genital infections and, amongst the host defence compounds, lactoferrin has recently acquired importance for its anti-microbial and anti-inflammatory properties. An abnormal genital microenvironment facilitates the acquisition of pathogens like Chlamydia trachomatis, the leading cause of bacterial sexually transmitted infections worldwide. The aim of our study is to investigate the effects of Lactobacillus crispatus, Lactobacillus brevis and bovine lactoferrin on chlamydial infection, in order to shed light on the complex interplay between host defence mechanisms and C. trachomatis. We have also evaluated the effect of these defence factors to modulate the chlamydia-mediated inflammatory state. To this purpose, we have determined the infectivity and progeny production of C. trachomatis as well as interleukin-8 and interleukin-6 synthesis. The main result of our study is that the combination of L. brevis and bovine lactoferrin is the most effective in inhibiting the early phases (adhesion and invasion) of C. trachomatis infection of cervical epithelial cells and in decreasing the levels of both cytokines. In conclusion, the interaction between L. brevis and lactoferrin seems to play a role in the protection against C. trachomatis, reducing the infection and regulating the immunomodulatory activity, thus decreasing the risk of severe complications.

HPV/Chlamydia trachomatis co-infection: metagenomic analysis of cervical microbiota in asymptomatic women

HPV and Chlamydia trachomatis are the most common causes of sexually transmitted diseases worldwide. Most infections are asymptomatic and left untreated lead to severe reproductive tract sequelae such as cervical cancer and infertility. Interestingly, C. trachomatis may also increase the susceptibility to HPV infection as well as contribute to viral persistence. Recently, a growing body of evidence has suggested that the composition of the cervico-vaginal microbiota plays a key role in the susceptibility and outcome of genital infections caused by several pathogens, including HPV and C. trachomatis. The aim of our study was to undertake a metagenomic analysis of sequenced 16s rRNA gene amplicons to characterize the cervical microbiota from asymptomatic women with HPV/C. trachomatis co-infection. The composition of the cervical microbiota from HPV-positive or C. trachomatis-positive women was also analysed. The main finding of our study showed that the cervical microbiota in HPV/C. trachomatis co-infected women had a higher microbial diversity than the cervical microbiota in healthy controls (p<0.05). In addition, Aerococcus christensenii was associated with C. trachomatis infection. In conclusion, the increased cervical microbial diversity observed in HPV/C. trachomatis co-infected women and the detection of potential microbiological biomarkers of C. trachomatis infection will open the way to innovative approaches that may be helpful to identify women at risk of co-infection.

Chlamydia Pneumoniae Infection in Patients with Acute Coronary Syndrome: A Clinical and Serological 1-Year Follow-Up

The role of Chlamydia pneumoniae infection in pathogenesis and prognostic stratification of patients with acute coronary syndromes is still unclear. However, a limitation of many studies is the evaluation of the long-term prognostic role of a sample obtained during the acute phase, whereas the assessment of the temporal trend of antibody titers could be more useful. One-hundred and fourteen consecutive patients with acute coronary syndromes (71 with acute myocardial infarction and 43 with unstable angina) were studied. Blood samples were obtained immediately after hospital admission and 1, 3, 6 and 12 months after the acute event. The microimmunofluorescence test was used to detect C. pneumoniae specific antibodies. The incidence of new coronary events (death, myocardial infarction, recurrent angina) was recorded during the 1-year follow-up period. No significant difference was found between patients with (n = 35) or without (n = 79) new coronary events (N.C.E.) regarding baseline and serial values of C. pneumoniae antibodies. The rate of high titers at any time of follow-up was also similar in the two groups: IgG ≥1:512 were present in 52%, 64%, 55% and 32% of N.C.E.+ patients, and in 48%, 54%, 52% and 36% of N.C.E.- patients at 1, 3, 6 and 12 months respectively; IgA ≥ 1:256 were present in 26%, 23%, 30% and 23% of N.C.E.+ patients and in 20%, 30%, 25% and 19% of N.C.E.- patients at 1, 3, 6 and 12 months respectively. Our data indicate that elevated titers of C. pneumoniae antibodies, even with a serial 1-year evaluation, are not a predictor of future coronary events in patients with acute myocardial infarction or unstable angina.

Diversity of Cervical Microbiota in Asymptomatic Chlamydia trachomatis Genital Infection: A Pilot Study

Chlamydia trachomatis genital infection continues to be an important public health problem worldwide due to its increasing incidence. C. trachomatis infection can lead to severe sequelae, such as pelvic inflammatory disease, obstructive infertility, and preterm birth. Recently, it has been suggested that the cervico-vaginal microbiota may be an important defense factor toward C. trachomatis infection as well as the development of chronic sequelae. Therefore, the investigation of microbial profiles associated to chlamydial infection is of the utmost importance. Here we present a pilot study aiming to characterize, through the metagenomic analysis of sequenced 16s rRNA gene amplicons, the cervical microbiota from reproductive age women positive to C. trachomatis infection. The main finding of our study showed a marked increase in bacterial diversity in asymptomatic C. trachomatis positive women as compared to healthy controls in terms of Shannon's diversity and Shannon's evenness (P = 0.031 and P = 0.026, respectively). More importantly, the cervical microbiota from C. trachomatis positive women and from healthy controls significantly separated into two clusters in the weighted UniFrac analysis (P = 0.0027), suggesting that differences between the two groups depended entirely on the relative abundance of bacterial taxa rather than on the types of bacterial taxa present. Furthermore, C. trachomatis positive women showed an overall decrease in Lactobacillus spp. and an increase in anaerobes. These findings are part of an ongoing larger epidemiological study that will evaluate the potential role of distinct bacterial communities of the cervical microbiota in C. trachomatis infection.

Lack of association of Chlamydia pneumoniae with cardiovascular diseases in virologically suppressed HIV patients

Cardiovascular disease (CVD) is a major public health problem in developed countries with over 17 million deaths per year. In the last decade, several infectious agents rather than any single pathogen, including Chlamydia pneumoniae and human immunodeficiency virus (HIV), have been shown to contribute to the development of atherosclerosis and subsequent cardiovascular events by inducing systemic inflammation and/or acting directly on the vascular wall. For the first time, we evaluated C. pneumonia DNA in peripheral blood mononuclear cells from HIV patients by real-time polymerase chain reaction in order to shed light on C. pneumonia as a co-factor with HIV in the development of CVDs. C. pneumonia DNA was not detected in our virologically suppressed HIV patients (<37 copies/mL). This finding may be related to high CD4+T cell count (>500 cells/μl) found in HIV patients suggesting functional cell-mediated immunity as a fundamental mechanism for the clearance of chlamydial infection in this population. Larger studies are needed to confirm this hypothesis.

Effect of bovine lactoferrin on Chlamydia trachomatis infection and inflammation

Chlamydia trachomatis is an obligate, intracellular pathogen responsible for the most common sexually transmitted bacterial disease worldwide, causing acute and chronic infections. The acute infection is susceptible to antibiotics, whereas the chronic one needs prolonged therapies, thus increasing the risk of developing antibiotic resistance. Novel alternative therapies are needed. The intracellular development of C. trachomatis requires essential nutrients, including iron. Iron-chelating drugs inhibit C. trachomatis developmental cycle. Lactoferrin (Lf), a pleiotropic iron binding glycoprotein, could be a promising candidate against C. trachomatis infection. Similarly to the efficacy against other intracellular pathogens, bovine Lf (bLf) could both interfere with C. trachomatis entry into epithelial cells and exert an anti-inflammatory activity. In vitro and in vivo effects of bLf against C. trachomatis infectious and inflammatory process has been investigated. BLf inhibits C. trachomatis entry into host cells when incubated with cell monolayers before or at the moment of the infection and down-regulates IL-6/IL-8 synthesized by infected cells. Six out of 7 pregnant women asymptomatically infected by C. trachomatis, after 30 days of bLf intravaginal administration, were negative for C. trachomatis and showed a decrease of cervical IL-6 levels. This is the first time that the bLf protective effect against C. trachomatis infection has been demonstrated.

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.

Chlamydia Pneumoniae in PBMC: Reproducibility of the OMPA Nested Touchdown PCR

The aim of our study was to evaluate whether the replicate PCR testing may provide more accurate estimates of C. pneumoniae DNA prevalence in PBMC of patients undergoing carotid endarterectomy. Clinical sensitivity and reproducibility of ompA nested touchdown PCR was also performed. Clinical sensitivity and reproducibility was examined by testing C. pneumoniae-negative PBMC spiked with serial dilutions of semipurified C. pneumoniae elementary bodies (from 8 to 0.002 IFU/ml). Detection of C. pneumoniae DNA was performed by ompA nested touchdown PCR. Each clinical and spiked PBMC DNA specimen was analyzed in replicates of 1,3,5 and 10. PCR results of serial dilutions of C. pneumoniae DNA performed in replicates of 10 were analysed by probit analysis.

C. pneumoniae DNA was detected in 14 of the 30 (46.7%) PBMC clinical specimens examined when 10 replicates were tested. When we analyzed 1, 3 and 5 replicates, 4 (13.3%), 7(23.3%), 12(40%) of the 30 specimens were positive, respectively. The limit of detection of ompA nested PCR touchdown was 0.008 IFU/ml when 10 replicates were tested. The ompA nested PCR had reproducibility scores of 10 for 10 from 8 to 4 IFU/ml concentration, but scores decreased for smaller numbers of IFU/ml. Our results showed that repeat testing of the same specimen increased clinical sensitivity as well as reproducibility of the ompA nested touchdown PCR. In conclusion the replicate PCR testing improves the performance of ompA nested touchdown PCR and provides a more accurate estimates of the prevalence of C. pneumoniae in PBMC of patients with atherosclerotic cardiovascular disease.

In Vitro Susceptibility of Isolates of Borrelia Burgdorferi S.L. to Antimicrobial Agents

In the present study, we investigate the in vitro antimicrobial activity of macrolides, β-lactams and tetracycline against Borrelia burgdorferi s.l. clinical and tick isolates. Minimal inhibitory concentrations (MICs) were determined in normal growth condition and after pre-exposure of the strains to sub-MIC of the founder of each drug family. All the classes of tested antibiotics showed good antibacterial activity against all the borreliae isolates and there were no significant susceptibility differences among clinical and tick isolates. After pre-exposure of the strains to sub-MIC of erythromycin, cefoxitin and tetracycline, we observed that some strains of B. burgdorferi s.l. showed higher MIC values to both the pre-exposed drug and drugs of the same family. The less susceptibility of borreliae, in the last growth condition in vitro, could be one of the justifications of clinical results indicating the limited efficacy of these antibiotics in treatment of B. burgdoferi infections.

Chlamydia pneumoniae Clinical Isolate from Gingival Crevicular Fluid: A Potential Atherogenic Strain

Chlamydia pneumoniae has been associated to atherosclerotic cardiovascular diseases. The aim of our study was to characterize, for the first time, a C. pneumoniae strain isolated from the gingival crevicular fluid of a patient with chronic periodontitis, described as a risk factor for cardiovascular diseases. C. pneumoniae isolate was characterized and compared to the respiratory AR-39 strain by VD4-ompA genotyping and by investigating the intracellular growth in epithelial and macrophage cell lines and its ability to induce macrophage-derived foam cells. Inflammatory cytokine levels were determined in the gingival crevicular fluid sample. C. pneumoniae isolate showed a 99% similarity with the AR-39 strain in the VD4-ompA gene sequence and shared a comparable growth kinetic in epithelial cells and macrophages, as evidenced by the infectious progeny and by the number of chlamydial genomic copies. C. pneumoniae isolate significantly increased the number of foam cells as compared to uninfected and LDL-treated macrophages (45 vs. 6%, P = 0.0065) and to the AR-39 strain (45 vs. 30%, P = 0.0065). Significantly increased levels of interleukin 1-β (2.1 ± 0.3 pg/μL) and interleukin 6 (0.6 ± 0.08 pg/μL) were found. Our results suggest that C. pneumoniae may harbor inside oral cavity and potentially be atherogenic, even though further studies will be needed to clarify the involvement of C. pneumoniae in chronic periodontitis as a risk factor for cardiovascular diseases.

Chlamydia pneumoniae and oxidative stress in cardiovascular disease: state of the art and prevention strategies

Chlamydia pneumoniae, a pathogenic bacteria responsible for respiratory tract infections, is known as the most implicated infectious agent in atherosclerotic cardiovascular diseases (CVDs). Accumulating evidence suggests that C. pneumoniae-induced oxidative stress may play a critical role in the pathogenesis of CVDs. Indeed, the overproduction of reactive oxygen species (ROS) within macrophages, endothelial cells, platelets and vascular smooth muscle cells (VSMCs) after C. pneumoniae exposure, has been shown to cause low density lipoprotein oxidation, foam cell formation, endothelial dysfunction, platelet adhesion and aggregation, and VSMC proliferation and migration, all responsible for the typical pathological changes of atherosclerotic plaque. The aim of this review is to improve our insight into C. pneumoniae-induced oxidative stress in order to suggest potential strategies for CVD prevention. Several antioxidants, acting on multi-enzymatic targets related to ROS production induced by C. pneumoniae, have been discussed. A future strategy for the prevention of C. pneumoniae-associated CVDs will be to target chlamydial HSP60, involved in oxidative stress.

Infectious burden and atherosclerosis: A clinical issue

Atherosclerotic cardiovascular diseases, chronic inflammatory diseases of multifactorial etiology, are the leading cause of death worldwide. In the last decade, more infectious agents, labeled as “infectious burden”, rather than any single pathogen, have been showed to contribute to the development of atherosclerosis through different mechanisms. Some microorganisms, such as Chlamydia pneumoniae (C. pneumoniae), human cytomegalovirus, etc. may act directly on the arterial wall contributing to endothelial dysfunction, foam cell formation, smooth muscle cell proliferation, platelet aggregation as well as cytokine, reactive oxygen specie, growth factor, and cellular adhesion molecule production. Others, such as Helicobacter pylori (H. pylori), influenza virus, etc. may induce a systemic inflammation which in turn may damage the vascular wall (e.g., by cytokines and proteases). Moreover, another indirect mechanism by which some infectious agents (such as H. pylori, C. pneumoniae, periodontal pathogens, etc.) may play a role in the pathogenesis of atherosclerosis is molecular mimicry. Given the complexity of the mechanisms by which each microorganism may contribute to atherosclerosis, defining the interplay of more infectious agents is far more difficult because the pro-atherogenic effect of each pathogen might be amplified. Clearly, continued research and a greater awareness will be helpful to improve our knowledge on the complex interaction between the infectious burden and atherosclerosis.

Effects of vaginal lactobacilli in Chlamydia trachomatis infection

Increasing evidence indicates that abnormal vaginal flora lacking lactobacilli facilitates the acquisition of several sexually transmitted diseases including Chlamydia trachomatis. C. trachomatis, the most common bacterial agent of genital infections worldwide, can progress from the lower to upper reproductive tract and induce severe sequelae. The ability of C. trachomatis to develop into a persistent form has been suggested as key pathogenetic mechanism underlying chronic infections and sequelae. The aim of our study was to investigate the C. trachomatis interaction with vaginal microbiota analyzing the effects of Lactobacillus strains (L. brevis and L. salivarius) on the different phases of C. trachomatis developmental cycle. In addition, the effect of lactobacilli on persistent chlamydial forms induced by HSV-2 coinfection has also been evaluated. Our results demonstrated significant inhibition of C. trachomatis multiplication by vaginal lactobacilli. L. brevis was significantly more effective than L. salivarius (p<0.05) on all the steps of chlamydial infection cycle suggesting that the ability of lactobacilli to protect from infection is strain-dependent. Lactobacilli had an adverse effect on elementary chlamydial bodies (p<0.05), on chlamydial adsorption to epithelial cells (p<0.001) and on intracellular phases of chlamydial replication (p<0.0001). Our study also demonstrated a protective effect of lactobacilli toward persistent C. trachomatis forms induced by HSV-2 coinfection. A significant increase in the production of C. trachomatis infectious progeny was observed in C. trachomatis/HSV-2 coinfection in the presence of L. brevis (p=0.01) despite a significant inhibition of C. trachomatis multiplication (p=0.028). Our data suggest that a healthy vaginal microbiota can reduce the risk of acquiring C. trachomatis infection and counteract the development of persistent chlamydial forms.

New insights into Chlamydiae persistence: an energy metabolism strategy?

Chlamydiaceae is a family of obligate intracellular bacteria generally considered energy parasites. Several studies have suggested that Chlamydiae are capable of independently producing energy and, more importantly, several genes involved in the energy metabolism are up-regulated during the persistent state. Thus, it has been suggested that chlamydial persistence could be a complex and flexible metabolic strategy designed to favor a lengthy survival in the host cell by evading the immune response. In conclusion, more detailed studies on the shift in the chlamydial energy metabolism, from the active to the persistent form, may be helpful in future to determine whether chlamydial persistence observed in vitro does occur in vivo and whether chronic sequelae of chlamydial diseases may be related to the persistence.

Human colonic myogenic dysfunction induced by mucosal lipopolysaccharide translocation and oxidative stress

BACKGROUND

Impairment of gastrointestinal motility is frequently observed in patients with severe infection.

AIM

To assess whether exposure of human colonic mucosa to pathogenic lipopolysaccharide affects smooth muscle contractility.

METHODS

Human colonic mucosa and submucosa were sealed between two chambers, with the luminal side facing upwards and covered with Krebs solution, with or without lipopolysaccharide from a pathogenic strain of Escherichia coli (O111:B4; 1,000 ng/mL), and with the submucosal side facing downwards into Krebs. The solution on the submucosal side was collected following 30-min mucosal exposure to Krebs without (N-undernatant) or with lipopolysaccharide (lipopolysaccharide undernatant). Undernatants were tested for lipopolysaccharide and hydrogen peroxide levels and for their effects on smooth muscle cells in the presence of catalase, indomethacin or MG132.

RESULTS

Smooth muscle cells incubated with N-undernatant had a maximal contraction of 32 ± 5% that was reduced by 62.9 ± 12% when exposed to lipopolysaccharide undernatant. Inhibition of contraction was reversed by catalase, indomethacin and MG132. Lipopolysaccharide levels were higher in the lipopolysaccharide undernatant (2.7 ± 0.7 ng/mL) than in N-undernatant (0.45 ± 0.06 ng/mL) as well as hydrogen peroxide levels (133.75 ± 15.9 vs 82 ± 7.5 nM respectively).

CONCLUSIONS

Acute exposure of colonic mucosa to pathogenic lipopolysaccharide impairs muscle cell contractility owing to both lipopolysaccharide mucosal translocation and production of free radicals.

Chlamydia pneumoniae infection in atherosclerotic lesion development through oxidative stress: a brief overview

Chlamydia pneumoniae, an obligate intracellular pathogen, is known as a leading cause of respiratory tract infections and, in the last two decades, has been widely associated with atherosclerosis by seroepidemiological studies, and direct detection of the microorganism within atheroma. C. pneumoniae is presumed to play a role in atherosclerosis for its ability to disseminate via peripheral blood mononuclear cells, to replicate and persist within vascular cells, and for its pro-inflammatory and angiogenic effects. Once inside the vascular tissue, C. pneumoniae infection has been shown to induce the production of reactive oxygen species in all the cells involved in atherosclerotic process such as macrophages, platelets, endothelial cells, and vascular smooth muscle cells, leading to oxidative stress. The aim of this review is to summarize the data linking C. pneumoniae-induced oxidative stress to atherosclerotic lesion development.

Chlamydia pneumoniae and osteoporosis-associated bone loss: a new risk factor?

We found an association between the presence of Chlamydia pneumoniae DNA both in osteoporotic bone tissue and peripheral blood mononuclear cells (PBMCs) and the increase in circulating resorptive cytokines.

INTRODUCTION

Our study was designed to determine whether C. pneumoniae infection may be involved in osteoporosis-associated bone loss.

METHODS

The study included 59 women undergoing hip joint replacement surgery for femoral neck fracture: 32 with osteoporosis and 27 with osteoarthritis. A total of 118 tissue specimens (59 bone tissues, 59 PBMCs) were examined for C. pneumoniae DNA by real-time polymerase chain reaction (PCR). Serum levels of soluble receptor activator of nuclear factor kappa B ligand (sRANKL), osteoprotegerin (OPG), interleukin (IL)-1β, tumor necrosis factor-α, and IL-6 were also measured.

RESULTS

C. pneumoniae DNA was detected in osteoporotic bone tissue whereas it was not found in non-osteoporotic bone tissue (p < 0.05). A significantly higher rate of C. pneumoniae DNA (p < 0.05) was found in PBMCs of osteoporotic patients than in those of osteoarthritis patients. Among osteoporotic patients, serum sRANKL, IL-1, and IL-6 concentrations as well as sRANKL/OPG ratio significantly differ between patients with bone tissue and PBMCs positive to C. pneumoniae and C. pneumoniae-negative patients.

CONCLUSION

The association between the presence of C. pneumoniae DNA, both in bone tissue and PBMCs, and the increase in sRANKL/OPG ratio as well as in IL-1β and IL-6 levels observed in osteoporotic patients suggests C. pneumoniae infection as a new risk factor for osteoporosis.

Resveratrol in Chlamydia pneumoniae-induced foam cell formation and interleukin-17A synthesis

The involvement of Chlamydia pneumoniae in the pathogenesis of atherosclerosis has been suggested by numerous seroepidemiological, in vivo and in vitro studies. In particular, it has been shown that C. pneumoniae is able to promote the accumulation of low-density lipoproteins into macrophages, thus facilitating foam cell formation. The aim of our study was to investigate the effects of resveratrol on macrophage derived foam cell formation induced by C. pneumoniae, examining its underlying biochemical mechanisms. Our results showed a relevant decrease in the number of foam cells, in the production of thiobarbituric acid reactive substances, superoxide anion and IL 17A while treating C. pneumoniae infected macrophages with resveratrol. Furthermore, the inhibition of Peroxisome Proliferator-Activated Receptors gamma by a specific antagonist (GW 9662), in presence of resveratrol and C. pneumoniae, enhanced intracellular lipid and cholesterol accumulation and the subsequent foam cell formation. In conclusion, the main result of our study is the evidence of an antiatherogenic effect of resveratrol on macrophage-derived foam cell formation and IL-17A production induced by C. pneumoniae.

Could past Chlamydial vascular infection promote the dissemination of Chlamydia pneumoniae to the brain?

Chlamydia pneumoniae, a pathogen responsible for respiratory tract infections, has been associated with atherosclerosis which, along with hypertension, hyperlipidemia, cardiovascular and/or cerebrovascular ischemia and stroke, is a risk factor for chronic neurological disorders. Several studies have demonstrated the ability of C. pneumoniae to disseminate from lungs to arteries through peripheral blood mononuclear cells. Once inside the vascular tissue, C. pneumoniae infection may disseminate via peripheral monocytes to the brain over the intact blood-brain barrier, and contribute to the development of chronic neurological disorders. The aim of our study was to evaluate whether past C. pneumoniae vascular infection may promote the dissemination of this microorganism to the brain, therefore we investigated the presence of C. pneumoniae in post-mortem brain tissue specimens of patients with past chlamydial vascular infection. Seventy six post-mortem brain tissue specimens from 19 patients with past chlamydial vascular infection were investigated for the presence of C. pneumoniae by immunohistochemistry, polymerase chain reaction, in situ polymerase chain reaction and in situ reverse transcription polymerase chain reaction. As control, 28 brain tissue specimens were taken from 7 age and sex matched subjects without chlamydial infection. C. pneumoniae was detected in 16 (84.2&#37;) out of 19 patients with chlamydial vascular infection whereas it was not detected in control subjects (p= 0.0002). In conclusion, the main result of our study is the evidence that a chlamydial vascular infection can disseminate to the brain. It will be important for current and future researches to perform large-scale prospective studies on cardiovascular patients with chlamydial vascular infection in order to evaluate the long-term pathological alterations of the brain.

The Elusive but Pathogenic Peptidoglycan of Chlamydiae

Chlamydia species cause a broad spectrum of diseases in humans including severe chronic sequelae related to persistent forms. Despite the lack of detectable amounts of peptidoglycan, several studies suggest the presence of small quantities of peptidoglycan or its derivative at least in some stages of the growth cycle. Based on recent discovery in Chlamydiae of the aminotransferase pathway for biosynthesis of meso-diaminopimelic acid, we demonstrated the up-regulation of the gene (cp0259) encoding L,L-diaminopimelate aminotransferase in chlamydial persistent forms. This finding may be important in the search for target molecules to diagnose and treat Chlamydia-associated chronic diseases.

Analysis of gene expression in penicillin G induced persistence of Chlamydia pneumoniae

Chlamydia pneumoniae is responsible for respiratory tract infections and has been associated to chronic diseases such as atherosclerosis. The involvement of C. pneumoniae in chronic diseases may be correlated to its ability to induce persistent forms in which Chlamydiae remain viable but are not cultivable. The aim of our study is to investigate C. pneumoniae specific gene activities associated with the development of Chlamydial persistence in a cell culture system in the presence of penicillin G. Chlamydia-infected HEp 2 cells were incubated with or without penicillin G for up to 72 hours. The relative mRNA expression levels of early and late genes in treated and untreated cell cultures were determined by Real-time RT-PCR. Our results revealed a consistent down-regulation of Chlamydial hctA and hctB genes (p=0.012 and p=0.003 respectively) in association with up-regulation of htrA gene (p=0.002) during penicillin G-induced persistence suggesting these gene sets as leading candidate for in vivo investigation of the development of persistent Chlamydial infection. In conclusion, the Chlamydial expression pattern of hctA, hctB, and htrA genes may be helpful to identify target molecules to diagnose and treat Chlamydia-associated chronic diseases.

Cutaneous Infection of Nocardia Altamirensis: The First Case Report

We report the first case of Nocardia altamirensis cutaneous infection in an immunocompetent host. A 53-year-old male, with no predisposing factors, presented with a suppurative papular nodule on the dorsum of his left foot. N. altamirensis was identified by sequencing the 16S ribosomal RNA (rRNA), and treatment with amikacin led to complete resolution of the clinical picture. We believe that cutaneous nocardiosis should be kept in mind as a possible cause of serious complications also in immunocompetent hosts considering a nonspecific clinical picture and misdiagnosis of the infection as well as the poor response to empirical antimicrobial therapy.

Chlamydia pneumoniae infection as a risk factor for accelerated atherosclerosis in hemodialysis patients

Atherosclerotic cardiovascular disease is the main cause of morbidity and mortality for end-stage renal disease patients undergoing chronic haemodialysis (HD). Several studies in recent years have identified Chlamydia pneumoniae, a respiratory pathogen, as risk factor for cardiovascular diseases in the general population. The aim of our study is to evaluate chlamydial load, in peripheral blood mononuclear cells (PBMC) of HD patients. Furthermore, the correlation between DNA chlamydial load and markers of inflammation was also examined. PBMC specimens isolated from 49 HD patients and 46 blood donors were analyzed for the presence of C. pneumoniae DNA by real-time PCR and ompA nested touchdown PCR. In HD patients, plasma levels of several inflammatory markers were also determined. A significantly higher rate of C. pneumoniae DNA was found in HD patients (44.9 percent) than in blood donors (19.6 percent) (p=0.016); HD patients were also more likely to have a significantly high chlamydial load (p=0.0004). HD patients with atherosclerotic cardiovascular diseases have a significantly greater chlamydial load than HD patients without cardiovascular diseases (p= 0.006). A significantly higher value of C-reactive protein, IL-6 and advanced oxidative protein products was found in HD patients with a greater chlamydial load (p less than 0.05). Likewise, a significantly lower monocyte HLA-DR percentage (p=0.011) as well as a lower monocyte HLA-DR expression were found in such patients (p= 0.007). In conclusion, our results show that HD patients are at high risk of C. pneumoniae infection correlated with chronic inflammatory response which in turn can lead to accelerated atherosclerosis and other long-term clinical complications such as myocardial infarction and stroke.

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

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)-alpha 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-alpha, 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-alpha 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.

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 and atherosclerosis: the role of mast cells

Chlamydia pneumoniae (C. pneumoniae), a respiratory pathogen, has been implicated in the pathogenesis of atherosclerosis, an inflammatory progressive disease, characterized by the formation of atherosclerotic plaques. Among several types of inflammatory cells involved in the atherogenesis process, recently particular attention has been directed toward the mast cells. Experimental studies have provided several mechanisms by which C. pneumoniae and mast cells could play a role in all stages of atherosclerosis, from initial inflammatory lesions to plaque rupture. C. pneumoniae, as well as mast cells, may actively participate both through the production of cytokines and matrix-degrading metalloproteinases and by provoking apoptosis of atheroma-associated vascular cells, key events in plaque rupture. This mini-review provides a brief overview on adventitial inflammatory effects of C. pneumoniae and mast cells and their potential role in plaque instability. In addition, in this paper we review the role of mast cells in innate immunity.