Namiot Db

Salivary mucins inhibit antibacterial activity of the cathelicidin-derived LL-37 peptide but not the cationic steroid CSA-13

OBJECTIVES Cationic antimicrobial peptides (CAPs) are the effector molecules of innate immunity, similar in potency to classic antibiotics that function in the first-line of defence against infectious agents. The purpose of this study was to investigate the effects of negatively charged mucins on the antibacterial activity of the positively charged cathelicidin LL-37 peptide, its synthetic analogue WLBU2 and the antimicrobial cationic steroid CSA-13. METHODS Mucin, DNA, F-actin and hCAP-18/LL-37 in saliva samples were evaluated by microscopy or immunoblotting. Bacterial killing assays and determination of MICs were used to determine bactericidal activity. Binding of rhodamine-B-labelled LL-37 peptide to mucin was fluorimetrically assessed. RESULTS Microscopic evaluation of saliva after addition of rhodamine-B-labelled LL-37 showed localization similar to that observed after the addition of a specific mucin-binding lectin. Immunoblotting confirmed the presence of hCAP-18/LL-37 in saliva samples and LL-37 peptide bound to isolated submaxillary gland mucin-coated plates. Mucin/LL-37 binding was partially prevented by treatment of mucin with neuraminidase, indicating involvement of sialic acid moieties. Decreased LL-37 and WLBU2 antibacterial activity was observed in the presence of mucin or dialysed human saliva, whereas CSA-13 antibacterial activity was significantly resistant to inhibition by mucins. CONCLUSIONS This study shows that the antibacterial LL-37 peptide and its synthetic analogue WLBU2 are inhibited by salivary mucin and that the cationic steroid CSA-13 retains most of its function in the presence of an equal amount of mucin or saliva.

Antibacterial activity of the human host defence peptide LL-37 and selected synthetic cationic lipids against bacteria associated with oral and upper respiratory tract infections

OBJECTIVES We aim to develop antibacterial peptide mimics resistant to protease degradation, with broad-spectrum activity at sites of infection. METHODS The bactericidal activities of LL-37, ceragenins CSA-13, CSA-90 and CSA-92 and the spermine-conjugated dexamethasone derivative D2S were evaluated using MIC and MBC measurements. Gingival fibroblast counting, interleukin-8 (IL-8) and lactate dehydrogenase (LDH) release from keratinocytes (HaCat) were used to determine effects on cell growth, pro-inflammatory response and toxicity. RESULTS All tested cationic lipids showed stronger bactericidal activity than LL-37. Incubation of Staphylococcus aureus with half the MIC of LL-37 led to the appearance of bacteria resistant to its bactericidal effects, but identical incubations with CSA-13 or D2S did not produce resistant bacteria. Cathelicidin LL-37 significantly increased the total number of gingival fibroblasts, but ceragenins and D2S did not alter gingival fibroblast growth. Cationic lipids showed no toxicity to HaCat cells at concentrations resulting in bacterial killing. CONCLUSIONS These data suggest that cationic lipids such as ceragenins warrant further testing as potential novel antibacterial agents.

The occurrence of Helicobacter pylori antigens in dental plaque; an association with oral health status and oral hygiene practices

PURPOSE Helicobacter pylori present in the oral cavity can be a source of gastric infection. Since in the oral cavity H. pylori is mostly found in dental plaque, the aim of the study was to determine whether the oral health status and oral hygiene practices affect the incidence of H. pylori antigens in dental plaque. MATERIALS AND METHODS The study was performed in 155 patients aged 19-78 years. Patients who had taken antibiotics within 4 weeks preceding the study and those with a past history of H. pylori eradication were excluded. Each patient filled out a questionnaire on the procedures of dental plaque removal from natural teeth and dentures, and underwent oral examination. H. pylori antigens in supragingival plaque were determined by the immunological method with the use of a kit for detection of H. pylori antigens in stool samples. RESULTS The presence of H. pylori antigens in dental plaque was found in 65.6% of the study subjects. The oral health status, frequency of dentist visits as well as the number and technique of dental plaque removal from natural teeth and dentures did not differ significantly between patients with infected and non-infected dental plaque. CONCLUSIONS The occurrence of H. pylori antigens in dental plaque of natural teeth is not associated with oral health status or dental plaque removal practices from both natural teeth and removable dentures.

Smoking and drinking habits are important predictors of Helicobacter pylori eradication.

PURPOSE The aim of the study was to evaluate the effect of smoking and drinking habits, in separate and joint analyses, on the efficacy of H. pylori eradication. MATERIALS AND METHODS A total of 250 patients were recruited. They were treated with a 7-day course of omeprazole, amoxicillin, tinidazole (OAT), omeprazole amoxicillin, clarithromycin (OAC) or omeprazole, clarithromycin, tinidazole (OCT). The efficacy of H. pylori eradication was tested with a CLO-test and histology 4 weeks after the completion of antibacterial therapy. RESULTS Drinking was found not to affect the efficacy of H. pylori eradication in any therapeutic group, while smoking decreased it in the OAC group (smokers 69.6%, non-smokers 94.3%, p=0.006). In the OAT treated group H. pylori eradication rate was lower in smokers-non-drinkers than in smokers-drinkers and non-smokers-non-drinkers (38.9% vs 83.2% and 70.0%, p=0.002 and p=0.034, respectively), while in the OAC treated group, smokers-non-drinkers had lower eradication efficacy than non-smokers-drinkers and non-smokers-non-drinkers (59.1% vs 100% and 91.3%, p=0.01 and p=0.012, respectively). In the OCT treated group, differences between subgroups were not significant. CONCLUSIONS Smoking and drinking habits when analyzed jointly are more useful to predict the outcome of H. pylori eradication than when analyzed separately.

Oral Health Status and Oral Hygiene Practices of Patients with Peptic Ulcer and How These Affect Helicobacter pylori Eradication from the Stomach

Background:  Helicobacter pylori eradication from the oral cavity is more difficult than from the stomach. Thus, if the bacterium survives the antibacterial therapy in the oral cavity, it would be able to re‐infect the stomach within a few weeks. Since oral health status could correspond to oral infection with H. pylori, the aim of the study was to determine whether oral health and oral hygiene practices affect the efficacy of H. pylori eradication from the stomach.

Application of immunoassay for detection of Helicobacter pylori antigens in the dental plaque.

PURPOSE The aim of this study was to determine the viability of the commercial test currently used for detection of H. pylori antigens in the stool for detection of H. pylori antigens in dental plaque. MATERIALS AND METHODS A total of 164 dyspeptic patients entered the study; 95 H. pylori infected (positive result of at least 4 of 5 diagnostic tests: Campylobacter-like organisms test (CLO test), histology, culture, stool antigens, serology) and 69 noninfected (negative results of 4 diagnostic tests: CLO test, histology, culture, stool antigens). Dental plaque was collected from natural teeth of the patients and incubated in microaerophilic conditions for 72 hours before immunoassay. RESULTS Experimental findings included that optimal dental plaque weight to perform the examination was over 2 mg and that preliminary incubation increased significantly the number of positive results (p<0.002). It was also found that H. pylori antigens in the dental plaque were positive in 81.2% of infected and only 17.7% of non-infected subjects (p<0.001), while the reproducibility of results was 95%. CONCLUSIONS The immunoassay for detection of H. pylori antigens in the stool may be used, after minor adaptations (specifically pre-incubation in microaerophilic conditions) for H. pylori antigen detection in dental plaque.

Patient factors affecting culture of Helicobacter pylori isolated from gastric mucosal specimens

PURPOSE Culture is one of the methods used for detecting Helicobacter pylori in the stomach. However, since it is costly, labor-consuming, and in a number of infected subjects gives a false negative result, the procedure is not routinely used. The aim of the study was to analyze some of the factors that may affect the outcome of H. pylori culture from endoscopic gastric mucosal specimens. MATERIAL AND METHODS The study was conducted in a group of 265 subjects. The culture of gastric mucosal specimens was verified by urease test and histological examination. If the culture result was not consistent with one or two verifying tests, an additional two tests were used, i.e. H. pylori antigens in stool samples and anti-H. pylori antibodies in blood serum. RESULTS In patients infected with H. pylori (at least two positive diagnostic tests), the analysis of factors that may affect the culture outcome revealed that neither age, gender, smoking, history of eradication, endoscopic diagnosis, use of proton pump inhibitors, ultrasonography of the abdomen or chest radiology performed the day before or on the day of gastroscopy, nor preparation for colonoscopy using osmotic fluids 1-2 days prior to gastroscopy had an effect on the culture outcome. Only high activity of gastritis (neutrophil infiltration) and low bacterial load in gastric mucosal specimens as well as drinking alcohol and the use of histamine H₂ receptor blockers reduced culture efficacy in infected subjects. CONCLUSIONS High activity of gastritis, low bacterial load, drinking alcohol and the use of histamine H₂ receptor blockers can be the cause of failed H. pylori culture from gastric mucosa in the infected subjects. These factors should be taken into consideration when qualifying patients for the test and interpreting the results.

Secretion of epidermal growth factor in saliva of duodenal ulcer patients; an association with Helicobacter pylori eradication and erosive esophagitis

PURPOSE Erosive esophagitis frequently develops after successful Helicobacter pylori eradication. Since salivary secretion of epidermal growth factor (EGF) plays a crucial role in the pathogenesis of gastroesophageal reflux disease, the current study objective was to find out whether erosive esophagitis development after Helicobacter pylori eradication is associated with the secretion of EGF in saliva. MATERIALS AND METHODS A total of 115 H. pylori infected patients (positive results of CLO-test, histology and serology) with a duodenal ulcer were recruited for the study. Gastroscopic examinations and saliva collections were performed twice, prior to H. pylori eradication and one year after its cessation. The salivary EGF was determined using a radioimmunological method. RESULTS Salivary EGF secretion was lower in H. pylori infected subjects with erosive esophagitis than without (0.82+/-0.66 vs 1.70+/-3.49 ng/min, p=0.021). However, a year after successful H. pylori eradication, salivary EGF did not differ between the groups (2.17+/-2.06 vs 1.79+/-2.06 ng/min); the lack of difference was due to high peptide secretion in patients who developed erosive esophagitis after eradication. CONCLUSION Erosive esophagitis development following H. pylori eradication is not the result of decreased salivary EGF secretion.

The use of immunological method for identification of helicobacter pylori in culture

The aim of the study was to establish whether the immune method detecting Helicobacter pylori antigens can be used for the identification of H. pylori from a culture. Bacteria were cultured from endoscopic specimens of gastric mucosa from 378 patients. A positive result of H. pylori culture was obtained in 166 patients (43.9%), while the presence of H. pylori antigens was obtained in 164 (98.8%). The classical method for H. pylori identification from a culture is characterized by high accuracy. Therefore, a positive result of the test for the presence of H. pylori antigens from the culture could only be additional evidence confirming the culture results in selected cases.