Dictamnine Inhibits the Adhesion to and Invasion of Uropathogenic Escherichia Coli (UPEC) to Urothelial Cells

Uropathogenic Escherichia coli (UPEC) is the most common pathogenic bacteria associated with urinary tract infection (UTI). UPEC can cause UTI by adhering to and invading uroepithelial cells. Fimbriae is the most important virulence factor of UPEC, and a potentially promising target in developing novel antibacterial treatments. In this study, the antibacterial properties and effects of the compound dictamnine, extracted from the traditional Chinese medicine Cortex Dictamni, on the bacterial morphology, cell adhesion, and invasion of UPEC were studied. Dictamnine exhibited no obvious antibacterial activity against UPEC, but significantly impeded the ability of UPEC to adhere to and invade uroepithelial cells. RT-qPCR analysis showed that treatment downregulated the expression of type 1 fimbriae, P fimbriae, and curli fimbriae adhesion genes, and also downregulated adhesion-related receptor genes of uroepithelial cells. Transmission electron microscopy showed that dictamnine destroyed the structure of the fimbriae and the surface of the bacteria became smooth. These results suggest that dictamnine may help to prevent UTI by simultaneously targeting UPEC fimbriae and urothelial adhesin receptors, and may have a potential use as a new anti-UPEC drug.

Occurrence of Helicobacter Pylori in Specimens of Chronic Gastritis and Gastric Adenocarcinoma Patients: A Retrospective Study at University Teaching Hospital, Kigali, Rwanda

Introduction: Helicobacter pylori (H. pylori) infection is the major cause of gastroduodenal diseases in populations of different ages.We conducted aretrospective studyusing archived tissue samples to determine the prevalence of H. pylori infection among patients diagnosed with gastritis and gastric adenocarcinoma by histopathology cases in one hospital in Rwanda. Materials and methods: Cases of chronic gastritis and gastric adenocarcinoma histologically diagnosed in a tertiary hospital in Rwanda over the period of 2016-2018 were studied for the presence of H. pylori using immunohistochemistry. Diagnosis of positive cases considered immunoreactivity as well as bacterial morphology, including spiral, rod-shaped, angulated and coccoid forms. Results: Three hundred and seven cases were included in this study; chronic gastritis and gastric adenocarcinoma representing 39% and 61%, respectively. The overall frequency of H. pylori infection was 77.5% (80% among chronic gastritis cases versus 76% among gastric adenocarcinoma cases). Prevalence of H. pylori infection in chronic gastritis and adenocarcinoma did not significantly associate with age and sex. Conclusion: The prevalence of H. pylori was high among chronic gastritis and gastric adenocarcinoma cases in Rwanda. Pathologists should investigate the presence of H. pylori in gastric biopsies. Our data shows immunohistochemistry method is feasible and adequate to facilitate detection of H. pylori, which may guide timely treatment.

Cell Wall Biology of Vibrio cholerae

Most bacteria are protected from environmental offenses by a cell wall consisting of strong yet elastic peptidoglycan. The cell wall is essential for preserving bacterial morphology and viability, and thus the enzymes involved in the production and turnover of peptidoglycan have become preferred targets for many of our most successful antibiotics. In the past decades, Vibrio cholerae, the gram-negative pathogen causing the diarrheal disease cholera, has become a major model for understanding cell wall genetics, biochemistry, and physiology. More than 100 articles have shed light on novel cell wall genetic determinants, regulatory links, and adaptive mechanisms. Here we provide the first comprehensive review of V. cholerae’s cell wall biology and genetics. Special emphasis is placed on the similarities and differences with Escherichia coli, the paradigm for understanding cell wall metabolism and chemical structure in gram-negative bacteria.

Silica Particles Trigger the Exopolysaccharide Production of Harsh Environment Isolates of Growth-Promoting Rhizobacteria and Increase Their Ability to Enhance Wheat Biomass in Drought-Stressed Soils

In coming decades, drought is expected to expand globally owing to increased evaporation and reduced rainfall. Understanding, predicting, and controlling crop plants’ rhizosphere has the potential to manipulate its responses to environmental stress. Our plant growth-promoting rhizobacteria (PGPR) are isolated from a natural laboratory, ‘The Evolution Canyon’, Israel, (EC), from the wild progenitors of cereals, where they have been co-habituating with their hosts for long periods of time. The study revealed that commercial TM50 silica particles (SN) triggered the PGPR production of exopolysaccharides (EPS) containing D-glucuronate (D-GA). The increased EPS content increased the PGPR water-holding capacity (WHC) and osmotic pressure of the biofilm matrix, which led to enhanced plant biomass in drought-stressed growth environments. Light- and cryo-electron- microscopic studies showed that, in the presence of silica (SN) particles, bacterial morphology is changed, indicating that SNs are associated with significant reprogramming in bacteria. The findings encourage the development of large-scale methods for isolate formulation with natural silicas that ensure higher WHC and hyperosmolarity under field conditions. Osmotic pressure involvement of holobiont cohabitation is also discussed.

Exploring the Gut Microbiome of Pregnant and Lactating Women from Antioquia-Colombia for Potential Biotherapeutics Enhancers of Choline Metabolism

Objectives To characterize the gut microbiome and build a collection of strains capable of metabolizing a specific dietary source rich in choline, from pregnant and lactating women of the region of Antioquia, Colombia Methods Fecal and blood samples were simultaneously collected from volunteers. Microbial cells were anaerobically isolated from fecal samples in an Egg Based Selective (EBS) medium, incubating at 37°C for 7 days. Afterwards, the colony-forming units per gram of fecal sample (CFU/g) were calculated for each volunteer, as the total biomass of culturable microorganisms capable of metabolizing a nutritional source rich in choline. Each bacterial morphology purified in EBS medium and Brain Heart Infusion (BHI) medium was cryopreserved at −80°C. Additionally, blood samples were analyzed by Abad Laboratorio obtaining the lipid profile of each volunteer. Data of CFU/g were analyzed using a non-parametric test. Correlation matrices of the total biomass and the physiological state of the volunteers, each of them with the lipid profile values, were performed in R software. Results Nineteen bacterial morphologies have been isolated, creating the first entries of the strains bank of choline metabolizing microorganisms. Total biomass values were between 1.89E + 08 and 2.10E + 10 CFU/g (± 6.96E + 09) and the Kruskal-Wallis test of total biomass in CFU/g denotes statistical significance among volunteers (P = 0,04). Besides, a significant correlation between the physiological state of volunteers and HDL was found, meaning that the lipid profile is affected during pregnancy and postpartum, as is widely recognized. Nevertheless, a non-previously reported correlation between total cholesterol, LDL and triglycerides with the total culturable choline-metabolizing microbial biomass from pregnant and lactating women was also found. Conclusions Total biomass of culturable choline-metabolizing microbiota is significantly variable among individuals and results suggest it being independent of the physiological state. Lactating and pregnancy states have an impact in the lipid profile, as has been previously reported. However, a novel finding in this study is that culturable microorganisms capable of metabolizing a nutritional source rich in choline as egg, impact the components of the lipidic profile. Funding Sources Universidad EAFIT Abad Laboratorio.

Comparison of Two Transmission Electron Microscopy Methods to Visualize Drug-Induced Alterations of Gram-Negative Bacterial Morphology

In this study, we optimized and compared different transmission electron microscopy (TEM) methods to visualize changes to Gram-negative bacterial morphology induced by treatment with a robenidine analogue (NCL195) and colistin combination. Aldehyde-fixed bacterial cells (untreated, treated with colistin or NCL195 + colistin) were prepared using conventional TEM methods and compared with ultrathin Tokuyasu cryo-sections. The results of this study indicate superiority of ultrathin cryo-sections in visualizing the membrane ultrastructure of Escherichia coli and Pseudomonas aeruginosa, with a clear delineation of the outer and inner membrane as well as the peptidoglycan layer. We suggest that the use of ultrathin cryo-sectioning can be used to better visualize and understand drug interaction mechanisms on the bacterial cell membrane.

DETERMINATION OF CONCENTRATION DEPENDENCE ON THE FORMATION OF FIBERS INDUCED BY Β-LACTAM IN GRAM-NEGATIVE BACTERIA

In this article, isolates of gram-negative bacteria producing extended-spectrum β-lactamases (ESBLs) were studied in a 4-hour incubation period under conditions of 5 concentrations of PbP-3 and PbP-1 dependent β-lactam antibiotics ceftazidime or сefotaxime. In the course of the study, modern research methods were used. It can be concluded that the relative degree of PBP binding, expressed in changes in bacterial morphology, may differ for each combination of an antibiotic and a bacterial species, group, or isolate. Since the resistance of gram-negative bacteria is a new problem in clinical practice, 14 isolates of E.coli and Klebsiella pneumoniae, which produce extended-spectrum beta-lactamases (ESBLs), were studied. Morphological changes after exposure to lactam antibiotics revealed certain patterns in various bacterial groups and isolators. In general, all Enterobacteriaceae isolates produced filaments in a relatively small concentration range. Filaments of Pseudomonas and Acinetobacter spp. they were produced in the presence of a clinically significant concentration of two antibiotics, which reaches 50 mg/l. Ceftazidime provoked the formation of filaments in a larger number of isolates and in greater concentrations than Cefotaxime. The number of bacteria the relationship between the formation of filaments and colony-forming units at concentrations of 0, 0.1, 5, 20, 30 mg/l in the presence of ceftazidime or cefotaxime E. coli was detected in an experiment using ATCC 25922. After incubation for 4 hours, the samples were sprinkled with blood agar. The article shows that 37 isolates of gram-negative bacteria collected during the experiment were detected using the Vitek 2 system and using Etests with a minimum inhibitory concentration (MIC). E.coli, C. pneumoniae and Klebsiella oxytoca, P. aeruginosa cells, infections caused by Acinetobacter baumannii, and Acinetobacter spp. other infections caused by cefotaxime and ceftazidime were tested to varying degrees resistance.

A Sarcina bacterium linked to lethal disease in sanctuary chimpanzees in Sierra Leone

Human and animal infections with bacteria of the genus Sarcina (family Clostridiaceae) are associated with gastric dilation and emphysematous gastritis. However, the potential roles of sarcinae as commensals or pathogens remain unclear. Here, we investigate a lethal disease of unknown etiology that affects sanctuary chimpanzees (Pan troglodytes verus) in Sierra Leone. The disease, which we have named “epizootic neurologic and gastroenteric syndrome” (ENGS), is characterized by neurologic and gastrointestinal signs and results in death of the animals, even after medical treatment. Using a case-control study design, we show that ENGS is strongly associated with Sarcina infection. The microorganism is distinct from Sarcina ventriculi and other known members of its genus, based on bacterial morphology and growth characteristics. Whole-genome sequencing confirms this distinction and reveals the presence of genetic features that may account for the unusual virulence of the bacterium. Therefore, we propose that this organism be considered the representative of a new species, named “Candidatus Sarcina troglodytae”. Our results suggest that a heretofore unrecognized complex of related sarcinae likely exists, some of which may be highly virulent. However, the potential role of “Ca. S. troglodytae” in the etiology of ENGS, alone or in combination with other factors, remains a topic for future research.

The role of Zur-regulated lipoprotein A in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles in Acinetobacter baumannii

Background Zinc uptake-regulator (Zur)-regulated lipoprotein A (ZrlA) plays a role in bacterial fitness and overcoming antimicrobial exposure in Acinetobacter baumannii. This study further characterized the zrlA gene and its encoded protein and investigated the roles of the zrlA gene in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles (OMVs) in A. baumannii ATCC 17978. Results In silico and polymerase chain reaction analyses showed that the zrlA gene was conserved among A. baumannii strains with 97–100% sequence homology. Recombinant ZrlA protein exhibited a specific enzymatic activity of D-alanine-D-alanine carboxypeptidase. Wild-type A. baumannii exhibited more morphological heterogeneity than a ΔzrlA mutant strain during stationary phase. The ΔzrlA mutant strain was more susceptible to gentamicin than the wild-type strain. Sizes and protein profiles of OMVs were similar between the wild-type and ΔzrlA mutant strains, but the ΔzrlA mutant strain produced 9.7 times more OMV particles than the wild-type strain. OMVs from the ΔzrlA mutant were more cytotoxic in cultured epithelial cells than OMVs from the wild-type strain. Conclusions The present study demonstrated that A. baumannii ZrlA contributes to bacterial morphogenesis and antimicrobial resistance, but its deletion increases OMV production and OMV-mediated host cell cytotoxicity.

Potential of Bacterial Cellulose Chemisorbed with Anti-Metabolites, 3-Bromopyruvate or Sertraline, to Fight against Helicobacter pylori Lawn Biofilm

Helicobacter pylori is a bacterium known mainly of its ability to cause persistent inflammations of the human stomach, resulting in peptic ulcer diseases and gastric cancers. Continuous exposure of this bacterium to antibiotics has resulted in high detection of multidrug-resistant strains and difficulties in obtaining a therapeutic effect. The purpose of the present study was to determine the usability of bacterial cellulose (BC) chemisorbed with 3-bromopyruvate (3-BP) or sertraline (SER) to act against lawn H. pylori biofilms. The characterization of BC carriers was made using a N2 adsorption/desorption analysis, tensile strength test, and scanning electron microscopy (SEM) observations. Determination of an antimicrobial activity was performed using a modified disk-diffusion method and a self-designed method of testing antibacterial activity against biofilm microbial forms. In addition, bacterial morphology was checked by SEM. It was found that BC disks were characterized by a high cross-linking and shear/stretch resistance. Growth inhibition zones for BC disks chemisorbed with 2 mg of SER or 3-BP were equal to 26.5–27.5 mm and 27–30 mm, respectively. The viability of lawn biofilm H. pylori cells after a 4-h incubation with 2 mg SER or 3-BP chemisorbed on BC disks was ≥4 log lower, suggesting their antibacterial effect. SEM observations showed a number of morphostructural changes in H. pylori cells exposed to these substances. Concluding, SER and 3-BP chemisorbed on BC carriers presented a promising antibacterial activity against biofilm H. pylori cells in in vitro conditions.