Lead Discovery Strategies for Identification of Chlamydia pneumoniae Inhibitors

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 [...].

A platform for studying the transfer of Chlamydia pneumoniae infection between respiratory epithelium and phagocytes

The obligate intracellular bacterium, Chlamydia pneumoniae, has been identified as a risk factor for several chronic inflammatory diseases in addition to respiratory tract infections. The dissemination of C. pneumoniae from respiratory tract to secondary sites of infection occurs via infected monocyte / macrophage line cells, in which C. pneumoniae can persist as an antibiotic-refractory phenotype. To allow more detailed studies on the epithelium-monocyte/macrophage transition of the infection, new in vitro bioassays are needed. To this end, a coculture system with human continuous cell lines was established. Respiratory epithelial HL cells were infected with C. pneumoniae and THP-1 monocytes were added into the cultures at 67 h post infection. After a 5 h coculture, THP-1 cells were collected with a biotinylated HLA antibody and streptavidin-coated magnetic beads and C. pneumoniae genome copy numbers in THP-1 determined by quantitative PCR. The assay was optimized for cell densities, incubation time, THP-1 separation technique and buffer composition, and its robustness was demonstrated by a Z' value of 0.6. The mitogen-activated protein kinase (MAPK) inhibitors: SP600125 (JNK inhibitor), SB203580 (p38 inhibitor) and FR180204 (ERK inhibitor) suppressed the transfer of C. pneumoniae from HL to THP-1 cells, making them suitable positive controls for the assay. Based on analysis of separate steps of the process, the MAPK inhibitors suppress the bacterial entry to THP-1 cells. The transfer of C. pneumoniae from epithelium to phagocytes represents a crucial step in the establishment of persistent infections by this pathogen, and the presented methods enables future studies to block this process by therapeutic means.

Prevalence of Ureaplasma urealyticum, Chlamydia trachomatis, and Neisseria gonorrhoeae in gynecological outpatients, Taizhou, China

OBJECTIVES

Ureaplasma urealyticum (UU), Chlamydia trachomatis (CT), and Neisseria gonorrhoeae (NG) are highly prevalent worldwide and may lead to some genital diseases. The objective of this large-scale study was to estimate the prevalence characteristics of UU, CT, and NG among women in Taizhou, Zhejiang Province, China.

METHODS

A total of 13 303 women who visited the gynecologic outpatient service of Taizhou First People's Hospital in Taizhou from 2013 to 2018 were analyzed. The testing of UU, CT, and NG was performed on the collected vaginal swabs using real-time fluorescence quantitative polymerase chain reaction (RT-PCR) method.

RESULTS

The overall infection rates of UU, CT, and NG were 62.04%, 10.20%, and 4.09% in the Taizhou-based population, respectively. The age-specific prevalence showed that younger women (age <25 years) were the preferred period for the positive detection of UU or CT, while elder women (age ≥40 years) had the highest prevalence of NG. In addition, the UU-CT co-infection pattern (7.32%) predominated in the study population, and CT was significantly associated with UU and NG.

CONCLUSIONS

Our novel data demonstrated that UU, CT, and NG infection are prevalent among women in Taizhou, and comprehensive UU, CT, and NG screening guidelines and treatment policies for this population are warranted.

Impact of dibenzocyclooctadiene lignans from Schisandra chinensis on the redox status and activation of human innate immune system cells

Redox signaling has been established as an essential component of inflammatory responses, and redox active compounds are of interest as potential immunomodulatory agents. Dibenzocyclooctadiene lignans isolated from Schisandra chinensis, a medicinal plant with widespread use in oriental medicine, have been implicated to possess immunomodulatory properties but their effects on the human innate immune system cells have not been described. In this contribution, data are presented on the impact of schisandrin, schisandrin B and schisandrin C on human monocytic cell redox status, as well as their impact on dendritic cell maturation and T cell activation capacity and cytokine production. In THP-1 cells, levels of intracellular reactive oxygen species (ROS) were elevated after 1 h exposure to schisandrin. Schisandrin B and schisandrin C decreased cellular glutathione pools, which is a phenotype previously reported to promote anti-inflammatory functions. Treatment of human primary monocytes with the lignans during their maturation to dendritic cells did not have any effect on the appearance of surface markers HLA-DR and CD86 but schisandrin B and schisandrin C suppressed the secretion of cytokines interleukin (IL)-6, IL-10 and IL-12 by the mature dendritic cells. Dendritic cells maturated in presence of schisandrin C were further cocultured with naïve CD4+ T cells, resulting in reduced IL-12 production. In THP-1 cells, schisandrin B and schisandrin C reduced the IL-6 and IL-12 production triggered by E. coli lipopolysaccharide and IL-12 production induced by an infection with Chlamydia pneumoniae. In conclusion, the studied lignans act as immunomodulatory agents by altering the cytokine secretion, but do not interfere with dendritic cell maturation. And the observed effects may be associated with the ability of the lignans to alter cellular redox status.

A PRISMA systematic review and meta-analysis on Chlamydia trachomatis infections in Iranian women (1986-2015)

BACKGROUND

Chlamydia trachomatis (CT) is the cause of genital tract infections in women. Some evidence has shown the role of this infection with CT in spontaneous abortions. The purpose of this study is to study the frequency of CT infection in Iranian women.

METHODS

This study was performed based on PRISMA guidelines. A total of 75 articles published in Google Scholar, PubMed, ISI Web of Science, Biological abs, Iranmedex, SID, and Scopus databases were found (1986-2015) using the following keywords: CT in women, CT and Iranian women, CT and infection in Iran, CT and pregnancy in Iran, CT and preterm delivery in Iran, CT and preterm labor in Iran, CT and fertility in Iran, CT and infertility in Iran, and CT and abortion in Iran. Finally, 40 studies from different regions of Iran were included. Statistical analyses were performed using R3 and STATA 12.

RESULTS

From 1986 to 2015, the lowest rate of prevalence was from 2010 to 2011 (3.9%) and the highest prevalence rate was in 2009 (69.39%) in northern Iran. Fixed effects for different parts of Iran (North, South, East, and West) were Pooled proportion: 0.13 (95% confidence interval [CI] = 0.12-0.14) and for samples (cervical, vaginal, urine, and blood) the pooled proportion was = 0.14 (95% CI = 0.12-0.14).

CONCLUSION

CT infection in this study was prevalent in urine samples and the rate of CT was observed from culture methods in comparison to other methods. Because women with CT play an important role because of sexual activity for transmission and untreated women are at risk of developing sequels. Also, most studies in Iran use sensitive polymerase chain reaction tests for the detection of genital CT infections.