Investigation of Chlamydia pneumoniae infection in Moroccan patients suffering from cardiovascular diseases

An overview of genes and mutations associated with Chlamydiae species' resistance to antibiotics

Background

Chlamydiae are intracellular bacteria that cause various severe diseases in humans and animals. The common treatment for chlamydia infections are antibiotics. However, when antibiotics are misused (overuse or self-medication), this may lead to resistance of a number of chlamydia species, causing a real public health problem worldwide.

Materials and methods

In the present work, a comprehensive literature search was conducted in the following databases: PubMed, Google Scholar, Cochrane Library, Science direct and Web of Science. The primary purpose is to analyse a set of data describing the genes and mutations involved in Chlamydiae resistance to antibiotic mechanisms. In addition, we proceeded to a filtration process among 704 retrieved articles, then finished by focusing on 24 studies to extract data that met our requirements.

Results

The present study revealed that Chlamydia trachomatis may develop resistance to macrolides via mutations in the 23S rRNA, rplD, rplV genes, to rifamycins via mutations in the rpoB gene, to fluoroquinolones via mutations in the gyrA, parC and ygeD genes, to tetracyclines via mutations in the rpoB gene, to fosfomycin via mutations in the murA gene, to MDQA via mutations in the secY gene. Whereas, Chlamydia pneumoniae may develop resistance to rifamycins via mutations in the rpoB gene, to fluoroquinolones via mutations in the gyrA gene. Furthermore, the extracted data revealed that Chlamydia psittaci may develop resistance to aminoglycosides via mutations in the 16S rRNA and rpoB genes, to macrolides via mutations in the 23S rRNA gene. Moreover, Chlamydia suis can become resistance to tetracyclines via mutations in the tet(C) gene. In addition, Chlamydia caviae may develop resistance to macrolides via variations in the 23S rRNA gene. The associated mechanisms of resistance are generally: the inhibition of bacteria’s protein synthesis, the inhibition of bacterial enzymes’ action and the inhibition of bacterial transcription process.

Conclusion

This literature review revealed the existence of diverse mutations associated with resistance to antibiotics using molecular tools and targeting chlamydia species’ genes. Furthermore, these mutations were shown to be associated with different mechanisms that led to resistance. In that regards, more mutations and information can be shown by a deep investigation using the whole genome sequencing. Certainly, this can help improving to handle chlamydia infections and healthcare improvement by decreasing diseases complications and medical costs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12941-021-00465-4.

Reliable and Sensitive Nested PCR for the Detection of Chlamydia in Sputum

Chlamydia are Gram-negative, intracellular pathogens colonizing epithelial mucosa. They cause primarily atypical pneumonia and have recently been associated with chronic diseases. Diagnostics relies almost exclusively on serological methods; PCR tests are used rarely because in patients with positive ELISA, it is nearly impossible to identify chlamydial DNA. This paradox is associated with DNA degradation in sputum samples, low abundance, and low sensitivity of PCR systems. In a newly designed and validated “nested” PCR (NPCR) assay, it was possible to amplify DNA of Chlamydia known to infect humans in 31% samples. The reliability of the assay was confirmed by DNA sequencing, and all PCR products belonged exclusively to the Chlamydiales, mainly recognized as Chlamydia pneumoniae. Three samples were related to Ca. Rhabdochlamydia porcellionis and Ca. Renichlamydia lutjani, which infect arthropods. In one case, samples were taken from sick individual, indicating the potential as a human pathogen.

Analysis of maslinic acid and gallic acid compounds as xanthine oxidase inhibitors in isoprenaline administered myocardial necrotic rats

OBJECTIVE

This research designed to analyze the in vivo and in silico ameliorative action of maslinic acid (MA) and gallic acid (GA) on reactive oxygen species generating enzyme xanthine oxidase (XO) in isoprenaline or isoproterenol (ISO) induced myocardial infarcted rats.

METHODS

Albino Wistar rats were categorized into four groups with eight rats in each group. A dose of 15 mg/kg of MA and GA were pretreated to each MA and GA groups for seven days. A dose of 85 mg/kg of ISO administered to the ISO group along with MA and GA groups except normal group on two consecutive days of pretreatment. All animals sacrificed and the heart tissues were collected for the analysis of XO. The in silico molecular docking analysis of the compounds MA and GA with XO was analyzed by using Gold 3.0.1 software.

RESULTS

XO enzyme levels were significantly increased in the heart homogenate of ISO administered rats when compared to normal rats. Pretreatment of MA and GA to ISO treated rats significantly brought XO enzyme to the near normal levels which indicate the protective action of MA and GA against myocardial necrosis. The in vivo results were further supported by the in silico molecular docking study which revealed the inhibition of XO enzyme by the formation of enzyme and ligand complex with the compounds MA and GA.

CONCLUSION

MA and GA compounds manifested the ameliorative effect against ISO administrated myocardial necrosis by inhibiting the free radical generating enzyme XO which is evidenced by both in vivo and in silico studies.

The association of Chlamydia pneumoniae infection with atherosclerosis: Review and update of in vitro and animal studies

Previous studies have tended to relate Chlamydia pneumoniae (Cpn) infection to atherosclerosis. However, while serological studies have mostly reinforced this hypothesis, inconsistent and even contradictory findings have been reported in various researches. Recent papers have pointed to the significance of Cpn in atherosclerotic lesions, which are regarded as the initiator and cause of chronic inflammation. This bacterium develops atherosclerosis by phenotypic changes in vascular smooth muscle cells, dysregulation of endothelin-1 in the vascular wall, and releasing pro-inflammatory cytokines from Toll-like receptor-2 (TLR2). Furthermore, Cpn infection, particularly under hyperlipidemic conditions, enhances monocyte adhesion to endothelium; changes the physiology of the host, e.g., cholesterol homeostasis; and activates the Low-density lipoprotein (LDL) receptor, which is the initial step in atherogenesis. On the other hand, it has been reported that Cpn, even without the immune system of the host, has the ability to stimulate arterial thickening. Moreover, there is evidence that Cpn can increase the impact of the classical risk factors such as hyperlipidemia, pro-inflammatory cytokines, and smoking for atherosclerosis. Furthermore, animal studies have shown that Cpn infection can induce atherosclerotic, which alongside hyperlipidemia is a co-risk factor for cardiovascular disease. Although the exact link between Cpn and atherosclerosis has not been determined yet, previous studies have reported possible mechanisms of pathogenesis for this bacterium. Accordingly, investigating the exact role of this infection in causing atherosclerosis may be helpful in controlling the disease.

Mechanism of salidroside relieving the acute hypoxia-induced myocardial injury through the PI3K/Akt pathway

OBJECTIVE

The objective was to investigate the anti-inflammatory effects of salidroside through the PI3K/Akt signaling pathway and its protective effects on acute hypoxia-induced myocardial injury in rats.

METHODS

A total of 24 healthy Sprague-Dawley male rats were selected as the experimental subjects. All rats were divided into 4 groups by using the random number table method, with 6 rats in each group. The groups included the normal control group, the salidroside group, the hypobaric hypoxia group, and the hypobaric hypoxia + salidroside group. Rats in the salidroside group were fed in the original animal laboratory and were intragastrically administered with salidroside every morning at a dosage of 35 mg/kg. Rats in the normal control group were intragastrically administered with an equal dosage of saline. Rats in the hypobaric hypoxia + salidroside group were intragastrically administered with salidroside every morning at a dosage of 35 mg/kg, who were fed in the hypoxic experiment module for animals. The altitude was increased to 4000 m, and the rats were kept in the module for 24 h. Rats in the hypobaric hypoxia group were intragastrically administered with an equal dosage of saline in the same environment, and the altitude was increased to 4000 m after administration. Parameters of blood gas analysis, histopathological changes in cardiac tissues, cardiac indexes, and inflammatory factors IL-6 and TNF-α levels of rats in groups were compared.

RESULTS

1. The cardiac indexes of rats in groups were compared. The differences between the hypobaric hypoxia group and the hypobaric hypoxia + salidroside group were statistically significant (P < 0.05). 2. The results of blood gas analysis of rats in groups were compared. The differences between the hypobaric hypoxia group and the hypobaric hypoxia + salidroside group were significantly different (P < 0.05). 3. In the hypobaric hypoxia group, the myocardial cells of rats were arranged disorderly and shaped differently, with cases such as edema, degeneration, necrosis, nucleus pyknosis, and massive infiltration of inflammatory cells. In the hypobaric hypoxia + salidroside group, the above-mentioned pathological changes in myocardial cells were relieved. 4. Compared with the hypobaric hypoxia group, in the hypobaric hypoxia + salidroside group, the concentrations of IL-6 and TNF-α in rats decreased apparently, and the differences were statistically significant (P < 0.05).

CONCLUSION

Salidroside had the repairing and protective effects on the hypobaric hypoxia-induced myocardial injuries in rats. The application of salidroside could reduce the inflammatory responses of rats with hypobaric hypoxia-induced myocardial injuries through PI3K/Akt signaling pathway, thereby protecting the myocardial cells.

Naked-Eye Enumeration of Single Chlamydia pneumoniae Based on Light Scattering of Gold Nanoparticle Probe

Chlamydia pneumoniae is a spherical zoonotic pathogen with a diameter of ∼200 nm, which can lead to a wide range of acute and chronic diseases in human body. Early and reliable on-site detection of C. pneumoniae is the key step to control the spread of the pathogen. However, the lack of a current technology with advantages of rapidity, ultrasensitivity, and convenience limits the implementation of traditional techniques for on-site detection of C. pneumoniae. Herein, we developed a naked-eye counting of C. pneumoniae based on the light scattering properties of gold nanoparticle (GNP) under dark-field microscopy (termed "GNP-labeled dark-field counting strategy"). The recognition of single C. pneumoniae by anti-C. pneumoniae antibodies-functionalized GNP probes with size of 15 nm leads to the formation of wreath-like structure due to the strong scattered light resulted from hundreds of GNP probes binding on one C. pneumoniae under dark-field microscopy. Hundreds of GNP probes can bind to the surface of C. pneumoniae due to the high stability and specificity of the nucleic acid immuno-GNP probes, which generates by the hybridization of DNA-modified GNP with DNA-functionalized antibodies. The limit of detection (LOD) of the GNP-labeled dark-field counting strategy for C. pneumoniae detection in spiked samples or real samples is down to four C. pneumoniae per microliter, which is about 4 times more sensitive than that of quantitative polymerase chain reaction (qPCR). Together with the advantages of the strong light scattering characteristic of aggregated GNPs under dark-field microscopy and the specific identification of functionalized GNP probes, we can detect C. pneumoniae in less than 30 min using a cheap and portable microscope even if the sample contains only a few targets of interest and other species at high concentration. The GNP-labeled dark-field counting strategy meets the demands of rapid detection, low cost, easy to operate, and on-site detection, which paves the way for early and on-site detection of infectious pathogens.

Changes in serum inflammatory factor interleukin-6 levels and pathology of carotid vessel walls of rats with chronic periodontitis and diabetes mellitus after the periodontal intervention

Objective

The effects of the periodontal intervention on rats with type-II diabetes mellitus (T2DM) and chronic periodontitis (CP) were explored through observing the changes in carotid artery pathology and interleukin-6 (IL-6) levels.

Methods

The rats were randomly divided into 5 groups, i.e. group A (the normal control group), group B (the T2DM control group), group C (the CP control group), group D (the T2DM + CP group), and group E (the periodontal intervention T2DM + CP group). Blood samples of rats were collected from angular veins respectively at the following 5 time nodes: 1 week before the intervention (T1), 1 week after the intervention (T2), 3 weeks after the intervention (T3), 5 weeks after the intervention (T4), and 7 weeks after the intervention (T5); IL-6 concentrations before and after the intervention were determined by the enzyme-linked immunosorbent assay (ELISA), and the pathology of carotid arteries were observed by the Hematoxylin-Eosin (HE) stain.

Results

The pathological results of carotid arteries showed that the blood vessels of rats in group A were normal in morphology; most of the carotid artery vessel walls of rats in groups B, C, and D were significantly thickened and the fibers were disorderly arranged; the increased thickness of vessel walls of rats in group E was reduced, a small number of foam cells and inflammatory cells were observed, and the irregular arrangement of fibers was improved. In terms of the IL-6 concentrations, during the period of T1-T5, in groups B, C, and D, the IL-6 concentrations in rats were increased (P < 0.05); after the periodontal intervention, in group E, the IL-6 concentrations in rats were first increased then decreased (P < 0.05).

Conclusion

In terms of the long-term effects, periodontal intervention may reduce the inflammations of patients with diabetes mellitus and periodontitis and improve the lesions of carotid arteries.

Chronic Inflammatory Diseases at Secondary Sites Ensuing Urogenital or Pulmonary Chlamydia Infections

Chlamydia trachomatis and C. pneumoniae are members of the Chlamydiaceae family of obligate intracellular bacteria. The former causes diseases predominantly at the mucosal epithelial layer of the urogenital or eye, leading to pelvic inflammatory diseases or blindness; while the latter is a major causative agent for pulmonary infection. On top of these well-described diseases at the respective primary infection sites, Chlamydia are notoriously known to migrate and cause pathologies at remote sites of a host. One such example is the sexually acquired reactive arthritis that often occurs at few weeks after genital C. trachomatis infection. C. pneumoniae, on the other hand, has been implicated in an extensive list of chronic inflammatory diseases which include atherosclerosis, multiple sclerosis, Alzheimer’s disease, asthma, and primary biliary cirrhosis. This review summarizes the Chlamydia infection associated diseases at the secondary sites of infection, and describes the potential mechanisms involved in the disease migration and pathogenesis.

Chlamydia pneumoniae sero-prevalence in Moroccan patients with cardiovascular diseases

BACKGROUND

Chlamydia pneumoniae is a pathogen associated with human respiratory tract infection, its viable presence in atherosclerotic plaques is also assumed to play significant function in cardiac diseases. Our study's main objective is to evaluate Chlamydia pneumoniae sero-prevalence in Moroccan patients with cardiovascular diseases using and comparing two serological methods.

METHODS

Two hundred eighteen patients were enrolled; serums were tested by microimmunofluorescence to explore the sero-prevalence. Simultaneously 74 serums were analyzed by both immunoblot and micro-immunofluorescence to evaluate recombinant proteins diagnosis value.

RESULTS

MIF results revealed 81% male and 84.5% female positive cases. The comparative study among 74 patients showed 78% men and 89% women positive cases by immunoblot, whereas MIF showed respectively 80% and 72%, a significant concordance between these methods was revealed. However, this comparison showed also two types of discrepancies, which may be related to difficulties in antigens detection by micro-immunofluorescence resulting from their structure complexity, or the antibodies reactivity with species' common antigens.

CONCLUSIONS

The study revealed a high sero-prevalence of Chlamydia pneumoniae in the studied population, a big interest of recombinant protein was also revealed in the diagnosis accuracy. We suggest therefore using immunoblot for diagnosis confirmation because it provides additional useful information.

A retrospective seroepidemiologic survey of Chlamydia pneumoniae infection in patients in Beijing between 2008 and 2017

Background

Chlamydia pneumoniae (C. pneumoniae) is an obligate intracellular bacterium and a human pathogen that causes respiratory infectious diseases. More than 50% of the adult population worldwide was once infected with C. pneumoniae, but investigations into this topic are insufficient in mainland China.

Methods

Anti-C. pneumoniae IgG and IgM antibodies were detected using micro-immunofluorescence test in serum samples of patients visiting Peking Union Medical College Hospital between 2008 and 2017 for routine medical purposes, and the aim of this retrospective study was to analyze the test results.

Results

Among 12,050 serum specimens tested for anti-C. pneumoniae IgG and IgM antibodies, the overall prevalence of anti-C. pneumoniae IgG antibodies was 86.6%, 87.2% for men and 86.0% for women. Adult men (>20 years) were found to have a significantly higher prevalence of anti-C. pneumoniae IgG than women (χ² = 30.32, P = 0.000). 3 to 5 years old patients were observed to have the lowest prevalence of anti-C. pneumoniae IgG, 42.8%, then increased with age, reaching the highest level of 98.6% in patients over 70 years of age. In the 10,434 specimens with C. pneumoniae IgG antibodies, the total geometric mean titer (GMT) for C. pneumoniae IgG was 45.71. Although GMTs were found to be significantly higher among all men than among all women (t = 5.916, P = 0.000), sex difference actually began in patients over 40 years of age and increased in the elderly. In the total 12,050 specimens, 1.2% had anti-C. pneumoniae IgM, 3.3% had anti-C. pneumoniae IgG with titers equal to or greater than 1:512; 0.39% had ≥4-fold increasing titers of antibodies in acute and convalescent phase paired samples, and 4.4% were finally confirmed to have acute antibodies against C. pneumoniae. 6 to 10 years old patients were found to have the highest rate of both IgM antibodies (3.9%) and acute antibodies (6.2%) against C. pneumoniae. Acute antibodies against C. pneumoniae were found to be more frequent in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD, 14.0%, χ² = 20.43, P = 0.000), patients with pneumonia (7.8%, χ² = 51.87, P = 0.000) and patients with acute respiratory tract infection (12.3%, χ² = 60.91, P = 0.000) than among all patients (4.4%). Both anti-C. pneumoniae IgG and IgM antibodies should be tested for acute antibodies against C. pneumoniae as testing for either alone will underestimate by a maximum of two-thirds the incidence of acute antibodies against C. pneumoniae.

Conclusions

More than 86% of Chinese patients on an average were once infected with C. pneumoniae. Adult men had both a higher prevalence and higher levels of antibodies than women. 6 to10 year old patients were found to have the most frequent acute infection of C. pneumoniae. C. pneumoniae is associated with AECOPD, pneumonia and acute respiratory tract infection. Anti-C. pneumoniae IgG and IgM should be tested simultaneously to avoid underestimation of acute antibodies against C. pneumoniae.