Effect of hyperbaric oxygen on the growth and susceptibility of facultatively anaerobic bacteria and bacteria with oxidative metabolism to selected antibiotics.

Wild strains of Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were tested in an experimental hyperbaric chamber to determine the possible effect of hyperbaric oxygen on the susceptibility of these strains to the antibiotics ampicillin, ampicillin + sulbactam, cefazolin, cefuroxime, cefoxitin, gentamicin, sulfamethoxazole + trimethoprim, colistin, oxolinic acid, ofloxacin, tetracycline, and aztreonam during their cultivation at 23 °C and 36.5 °C. Ninety-six-well inoculated microplates with tested antibiotics in Mueller-Hinton broth were cultured under standard incubator conditions (normobaric normoxia) for 24 h or in an experimental hyperbaric chamber (HAUX, Germany) for 24 h at 2.8 ATA of 100% oxygen (hyperbaric hyperoxia). The hyperbaric chamber was pressurised with pure oxygen (100%). Both cultures (normoxic and hyperoxic) were carried out at 23 °C and 36.5 °C to study the possible effect of the cultivation temperature. No significant differences were observed between 23 and 36.5 °C cultivation with or without the 2-h lag phase in Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Cultivation in a hyperbaric chamber at 23 °C and 36.5 °C with or without a 2-h lag phase did not produce significant changes in the minimum inhibitory concentration (MIC) of Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. For the tested strains of Pseudomonas aeruginosa, the possible effect of hyperbaric oxygen on their antibiotic sensitivity could not be detected because the growth of these bacteria was completely inhibited by 100% hyperbaric oxygen at 2.8 ATA under all hyperbaric conditions tested at 23 °C and 36.5 °C. Subsequent tests with wild strains of pseudomonads, burkholderias, and stenotrophomonads not only confirmed the fact that these bacteria stop growing under hyperbaric conditions at a pressure of 2.8 ATA of 100% oxygen but also indicated that inhibition of growth of these bacteria under hyperbaric conditions is reversible.

Antibiotic resistance and biofilm-forming ability of α-toxin-positive Clostridium septicum isolates worsen patient prognosis.

A total of, 78 Clostridium septicum (CLSE) isolates were screened for genes encoding: α-toxin, flagellin, and resistance to vancomycin (VANg). The isolates were also tested for their ability to form biofilm and their antibiotic susceptibility. All isolates were positive for α-toxin and flagellin genes. However, only 19 isolates (24.3%) showed prevalence for VANg. We observed the strongest capacity to form a biofilm (100%) in isolates from patients with oncologic or septic and febrile diagnoses. This percentage was also very high in patients with colitis and gastrointestinal hemorrhage (72.7%). No less than 43 isolates showed antibiotic resistance, and 21 were multidrug-resistant (MDR). Interestingly, our studies showed a correlation between antibiotic resistance and biofilm formation. A statistically significant difference was observed between biofilm-forming MDR isolates and those with low/no biofilm-forming ability. However, the most impressive observation was the correlation with mortality rate. While the overall mortality rate for CLSE infections was 16.7% (13/78), the mortality rate for patients infected with MDR isolates forming biofilm moderately or strongly reached 38.1% (8/21). This number increased even further when only infections with the biofilm-forming VANg-positive isolates were considered (61.5%; 8/13). Therefore, the ability of a VANg-positive CLSE isolate to form a biofilm has been suggested as a biomarker of poor prognosis.

Detection and molecular characterization of VRE isolates in Slovakia from stool samples positive for Clostridioides difficile toxins.

The study aimed to identify colonized patients as a possible source of eventual VRE (vancomycin-resistant enterococci) infection from stool samples positive for glutamate dehydrogenase antigen, as well as for Clostridioides difficile toxins A and B. The study was carried out from 7/2020 to 9/2021. Stool samples were grown in a brain heart infusion medium with a gram-positive non-spore-forming bacteria supplement under aerobic conditions. The samples for VRE identification were grown on CHROMID® VRE agar, and the MICs for vancomycin and teicoplanin were also estimated. The presence of the vanA/vanB genes was tested using the PCR method. The total number of 113 stool samples positive for Clostridioides difficile toxins was analyzed. Of these samples, 44 isolates with VRE characters were identified. The most prevalent isolates in our set of isolates were Enterococcus faecium (27 isolates, 62%), Enterococcus faecalis (9 isolates, 21%), Enterococcus solitarius (4 isolates, 9%), Enterococcus durans (2 isolates, 4%), 1 isolate Enterococcus sulfurous (2%), and Enterococcus raffinosus (2%). In total, 26 isolates were detected in the study in the presence of vanA genes (24 isolates E. faecium, 2 isolates E. faecalis) and 18 isolates detected in the presence of vanB genes (7 isolates E. faecalis, 4 isolates E. solitarius, 3 isolates E. faecium, 2 isolates E. durans, 1 isolate E. sulfurous, and E. raffinosus). The results of this study showed the local dominance character of the vanA gene of hospital VRE isolates that were carriers of genes associated with high resistance to vancomycin, teicoplanin, and occasionally linezolid.

The role of intestinal microbiota in the pathogenesis of colorectal carcinoma.

The symbiotic relationship between intestinal microbiota and the host is a major mechanism of prevention against the development of chronic and metabolic diseases. The intestinal microbiota provides several physiological functions of the organism from the creation of a natural functional barrier with a subsequent immunostimulatory activity up to affecting the energy metabolism of the host. Disruption of physiological intestinal microbiota is reported as one of the major etiological factors of initiation and progression of colorectal carcinoma (CRC). Chronic low-grade inflammation is associated with the development of CRC, through the production of inflammatory cytokines and reactive oxygen species. CRC occurs in association with high-protein and high-fat diets in combination with low-fiber intake. The problem of intestinal dysbiosis and oncological diseases is a multidisciplinary problem and it is necessary to focus on several fields of medicine such as public health, clinical pharmacology, and internal medicine. The aim of this review is describing the role of gut dysbiosis in pathogenesis of colorectal carcinoma.

Elevated Circulating PCSK9 Concentrations Predict Subclinical Atherosclerotic Changes in Low Risk Obese and Non-Obese Patients.

INTRODUCTION: Many studies have highlighted the important role of PCSK9 in the development of cardiometabolic changes and its possible function as a biomarker of myocardial infarction or ischemic heart disease. This study aimed to determine the relationship between circulating PCSK9 levels and subclinical vascular changes in the group of low risk patients without manifest cardiovascular diseases. METHODS: In this study, 120 healthy patients, free of manifest cardiovascular diseases, diabetes mellitus, and without lipid-lowering therapy, were divided into three groups based on BMI: normal weight (N = 50), overweight (N = 30), and obese (N = 40). Biochemical parameters, including basic lipid and non-lipid ones, were analyzed. PCSK9 levels were measured by ELISA, vascular changes were quantified by carotid ultrasound (carotid artery intima-media thickness, cIMT), and arterial stiffness parameters (pulse wave velocity, PWV; augmentation index, AI; stiffness parameter, ß) were measured by an echo-tracking method. RESULTS: Plasma levels of PCSK9 significantly increased in obese (172.78 ± 51.67 ng/mL) in comparison with overweight (120.14 ± 37.64, p < 0.001) and normal weight groups (114.92 ± 35.87, p < 0.001). Differences between the overweight and normal weight groups were not significant (p = 0.85). The level of PCSK9 significantly correlated with values of BMI (p < 0.001, r = 0.38). In addition to increase in laboratory parameters associated with moderate metabolic changes, significant increase in cIMT and parameters of vascular changes (ß, AI, PWV) were detected in groups with elevated BMI. Significant positive linear correlation of PCSK9 concentrations and cIMT (p < 0.001, r = 0.39), PWV (p < 0.001, r = 0.31), and ß (p < 0.001, r = 0.3) were found. In multivariable regression analysis after adjusting for gender, age, BMI, and LDL, the impact of PCSK9 on cIMT, ß, and PWV remained significant (p = 0.006, 0.03, and 0.002, respectively). CONCLUSION: PCSK9 plasma levels significantly correlated with subclinical vascular changes and their values were significantly elevated in obese subjects. We assume that PCSK9 could be used as a predictor of early vascular involvement, prior to the existence of manifest atherosclerosis. These results also highlight the role of anti-PCSK9 treatment in primary prevention.

Ability of Lactobacillus plantarum LS/07 to modify intestinal enzymes activity in chronic diseases prevention.

The ability of probiotic strain Lactobacillus plantarum LS/07 to modify the activity of intestinal bacterial enzymes - ß-glucuronidase (ß-GLUCUR), ß-galactosidase (ß-GAL), and ß-glucosidase (ß-GLU) in prevention of chronic diseases - cancer, atherosclerosis and dysbiosis was investigated. The male Sprague-Dawley rats were randomly divided into 12 experimental groups: controls groups - C (control), AT (atherosclerotic), CC (carcinogenic), dysbiotic groups - each group in combination with antibiotics (ATB), probiotics groups - in combinatioan with probiotic (PRO) alone, and each group with combination of antibiotic and probiotic (ATB+PRO). In the control group the ß-glucuronidase activity did not change throughout the experiment. High fat diet in atherosclerotic group significantly increased the activity of ß-glucuronidase (P<0.001) and ß-glucosidase (P<0.01). Azoxymethane application in carcinogenic group significantly increased ß-glucuronidase (P<0.01), but reduced ß-glucosidase (P<0.01) activity. Daily application of probiotics alone and in combination with antibiotic increased ß-galactosidase, of ß-glucosidase, and decreased ß-glucuronidase activity. In control antibiotic group we observed significant increase in ß-glucuronidase (P<0.05) and decreased ß-glucosidase (P<0.01) activity which can be caused by the change of microflora in favor of coliform bacteria. These findings indicate the positive effects of probiotic Lactobacillus plantarum LS/07 and suggest its use in disease prevention in human medicine and some animal species.

Preventive use of Lactobacillus plantarum LS/07 and inulin to relieve symptoms of acute colitis.

The aim of presented study was to investigate the influence of Lactobacillus plantarum LS/07 and inulin on the activity of ß-glucuronidase enzyme, and counts of coliform and lactobacilli in fresh caecal digesta, cytokine levels (IL-6, IL-8), and trancription nuclear factor kappa beta (NFκB) activities in colon tissue and blood samples of rats with dextran sulphate sodium (DSS) induced acute colitis. The rats were randomly divided into four groups - CG, AC, AC+PRE and AC+PRO. Colitis was induced using of 5% DSS in drinking water for 7d. DSS application increased activity of ß-glucuronidase (P < 0.001), increased counts of coliforms, and decreased lactobacilli counts (P < 0.05) in comparison to control group. Serum and tissue levels of IL-6 and IL-8 as well as tissue NFκB activities showed increased expression in acute colitis group. Inulin diet modified counts of microorganims and decreased ß-glucuronidase activity, suppressed NFκB activities (P < 0.001) and down regulate synthesis of IL-6 (P < 0.01) in serum and colon tissue and tissue IL-8 (P < 0.05). Lactobacillus plantarum LS/07 decreased ß-glucuronidase activity (P < 0.05), levels of IL-6 and IL-8 (P < 0.001). These results were consistent with the addition of histological findings. Our results indicate that dietary intake of Lactobacillus plantarum LS/07 and inulin suppressed expression observed markers, which play an important role in the inflammatory process, which predisposes their use in prevention or treatment of acute colitis.