Effect of exopolysaccharides from cariogenic bacteria on human gingival fibroblasts.

Bacterial biofilm (dental plaque) plays a key role in caries etiopathogenesis and chronic periodontitis in humans. Dental plaque formation is determined by exopolysaccharides (EPSs) produced by cariogenic and periopathogenic bacteria. The most frequent cariogenic bacteria include oral streptococci (in particular S. mutans) and lactobacilli (most frequently L. acidophilus). In turn, the dominant periopathogen in periodontitis is Porphyromonas gingivalis. Development of dental caries is often accompanied with gingivitis constituting the mildest form of periodontal disease. Basic cellular components of the gingiva tissue are fibroblasts the damage of which determines the progression of chronic periodontitis. Due to insufficient knowledge of the direct effect of dental plaque on metabolic activity of the fibroblasts, this work analyses the effect of EPSs produced by S. mutans and L. acidophilus strains (H2O2-producing and H2O2-not producing) on ATP levels in human gingival fibroblasts (HGF-1) and their viability. EPSs produced in 48-hours bacterial cultures were isolated by precipitation method and quantitatively determined by phenol - sulphuric acid assay. ATP levels in HGF-1 were evaluated using a luminescence test, and cell viability was estimated using fluorescence test. The tests have proven that EPS from S. mutans did not affect the levels of ATP in HGF-1. Whereas EPS derived from L. acidophilus strains, irrespective of the tested strain, significantly increased ATP levels in HGF-1. The analysed EPSs did not affect the viability of cells. The tests presented in this work show that EPSs from cariogenic bacteria have no cytotoxic effect on HGF-1. At the same time, the results provide new data indicating that EPSs from selected oral lactobacilli may have stimulating effect on the synthesis of ATP in gingival fibroblasts which increases their energetic potential and takes a protective effect.

MUC7 Level As A New Saliva Risk Factor For Dental Caries In Adult Patients.

Purpose: Data currently available indicate the significance of salivary mucins MUC5B and MUC7 in the protection of teeth against caries. Our study aimed to determine the relationship between dental caries in adults and levels of MUC5B and MUC7. Methods: The studies were conducted on 45 adult subjects selected on the basis of dental examination and calculation of the DMFT (Decayed, Missing, and Filled Teeth) index. Among these patients, two research groups were distinguished: group 1 included 19 caries-free subjects (DMFT = 0); and group 2 included 26 patients with severe caries (DMFT > 13.9). Samples of whole unstimulated saliva were collected and centrifuged. MUC5B and MUC7 content in saliva supernatant were estimated using an enzyme-linked immunosorbent sandwich assay (ELISA). Analysis of the obtained data receiver operating characteristic (ROC) curves was employed to define relationships between the contents of the studied mucins and the detected dental caries. Results: In subjects from group 1, the mean level of MUC5B amounted to 0.63 ± 0.35 ng/ml and this was significantly higher than the concentration of mucin in patients of group 2, which amounted to 0.38 ± 0.32 ng/ml (p = 0.023). The mean level of MUC7 amounted to 5.47 ± 1.18 ng/ml and this was significantly higher than the level of the mucin in group 2, which was 1.39 ± 0.86 ng/ml (p< 0.0001). In parallel, a relationship was detected between levels of the examined mucins and manifestation of dental caries. For MUC7, the optimal cut-off value was obtained (i.e. corresponding to 100% sensitivity and specificity), amounting to 2.5 ng/ml for the detection of dental caries risk. Conclusions: Development of dental caries is linked to reduced concentrations of MUC5B and MUC7. The level of MUC7 may represent a significant parameter clinically suitable for evaluation of disease risk.

Cowpox virus infection in a child after contact with a domestic cat: a case report.

Human cowpox represents a seldom diagnosed zoonosis but this diagnosis should be considered more frequently as the number of cases has increased in recent years. We describe a case of cowpox in an 11-yearold boy following regular direct daily contact with a domestic cat. The 11-year-old patient, an otherwise healthy boy, demonstrated skin ulceration located at his chin, with enlargement of regional lymph nodes and fever reaching 39°C. The diagnosis of cowpox was made on the basis of PCR involving DNA isolated from a scab covering the skin lesion. Application of PCR involving DNA isolated from the scab covering the lesion with parallel use of OPXV-specific (ORF F4L) and CPXV-specific (ORF B9R) oligonucleotide primer sequences is recommended for rapid laboratory confirmation of the diagnosis.

The Participation of p53 and bcl-2 Proteins in Gastric Carcinomas Associated with Helicobacterpylori and/or Epstein-Barr Virus (EBV).

In the presented studies p53 and bcl-2 proteins expression were evaluated in samples of gastric carcinomas in patients with Helicobacter pylori or EBV or without H. pylori/EBV infection. The studies were conducted on 64 adult patients with gastric adenocarcinomas: 16 patients with H. pylori (cagA+)-positivity (group 1), 14 with EBV-positive tumours (group 2), 12 with H. pylori/EBV-positive tumours (group 3) and 22 patients with H. pylori/EBV-negative tumours (group 4). H. pylori presence in gastric tumour specimens was detected using Giemsa staining and bacterial culture technique. Moreover, cagA gene was detected using PCR. EBV infection was detected based on EBER presence in the tissue by RNA in situ hybridization. Expressions of p53 and bcl-2 proteins were analysed using immunohistochemistry. Expression of p53 was noted in 14 (84%) patients from group 1, 8 (57%) patients from group 2, 7 (58%) patients from group 3, and 19 (86%) patients from group 4, whereas expression of bcl-2 was noted in 12 (75%) patients from group 1, in 10 (71%) patients from group 2, 9 (75%) patients from group 3, and 6 (27%) patients from group 4. The obtained results allow the conclusion, that H. pylori (cagA+)-associated development of the gastric adenocarcinoma is determined by abnormalities in the p53 protein function and overexpression of anti-apoptotic bcl-2 protein, whereas EBV-associated adenocarcinomas seem to be related with apoptosis resistance associated with bcl-2 overexpression.

Opposite effect of supernatants from selected periopathogens and oral lactobacilli cultures on ATP levels in human gingival fibroblasts.

Studies were performed on the effects of supernatants obtained from bacterial cultures, including cultures of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Lactobacillus acidophilus strains on ATP levels in human gingival fibroblasts (HGF-1) and on their viability. ATP levels were evaluated using luminescence test and cell viability was estimated using a fluorescence test. In control cultures mean levels of ATP in HGF-1 amounted to 4.90±0.32 mln RLU. Supernatants of P. gingivalis and A. actinomycetemcomitans cultures were found to significantly reduce ATP production in HGF-1 (mean levels of ATP amounted to 3.41±0.33 and 3.55±0.3 mln RLU respectively), which was not accompanied by an increased proportion of dead fibroblasts. Supernatants of P. intermedia induced no significant alterations in ATP level in HGF-1. In turn, supernatants of L. acidophilus H2O2 (+) and H2O2 (-) cultures significantly increased ATP levels in HGF-1 (the mean levels amounted to 5.94±0.31 mln RLU and 5.88±0.28 mln RLU respectively). The results indicate that extracellular products of P. gingivalis and A. actinomycetemcomitans most probably represent mitochondria-targeted peptides, which reduce synthesis of ATP in HGF-1. In turn, extracellular products of L. acidophilus seem to represent exopolysaccharides (EPS) with pro-oxidant activity, which stimulate synthesis of ATP in HGF-1.

[Occurrence of Chlamydia trachomatis infections in infertile women in Poland]. / Wystepowanie zakaien Chlamydia trachomatis u kobiet z nieplodnoscia w Polsce.

INTRODUCTION: Chiamydia trachomatis represents a causal factor of sexually transmitted infections (STI), the course of which is frequently asymptomatic. Chronic and relapsing infections with Chlamydia trachomatis may result in a disturbed function of oviducts, resulting in infertility. OBJECTIVES: The aim of the study was to evaluate the relationship between manifestations of asymptomatic infections with Chlamydia trachomatis and infertility among Polish women. MATERIAL AND METHODS: The study was conducted between 2010-2013 on 543 women in two groups. Group 1 included 190 patients (aged 23-39 years), in whom control tests were performed before planned pregnancy Group 2 included 353 patients (aged 23-39 years), suffering from infertility (no pregnancy after 12 months of regular sexual intercourse). The study included all women presenting with infertility A smear was taken from the cervical canal and DNA of C. trachomatis was isolated and identified using nested-PCR. In the statistical analysis the Fisher's exact test was applied. RESULTS: Infection with C. trachomatis was detected in 18 (9.47%) controls (group 1) but as many as 81 (22.95%) patients with infertility (group 2). The obtained results were significantly different (p<0.0001) between the investigated groups. CONCLUSIONS: (1) The study indicates that chronic infection with C. trachomatis may represent a significant factor resulting in infertility of women. (2) A test for Chlamydia trachomatis infection should be routinely performed in every couple with diagnosed infertility and always before a scheduled in vitro procedure.

Towards a more effective strategy for COVID-19 prevention (Review).

At the end of 2019, a new disease, similar to severe acute respiratory syndrome (SARS) associated with SARS-CoV was reported in Wuhan, China. It was quickly discovered that the etiological factor of the new disease (COVID-19) was a previously unknown SARS coronavirus 2 (SARS-CoV-2). The global spread of of COVID-19 has lead to the declaration of a pandemic status in 2019-2020 as declared by the World Health Organization and Public Health Emergency of International Concern. SARS-CoV-2 characterizes with high epidemic potential and is effectively disseminated between humans. SARS-CoV and SARS-CoV-2 are closely related pathogens. Their prime route of distribution is air-droplet transmission. Combating infectious diseases disseminated by inhalation is very difficult, and mainly relies on the use of vaccines. However, despite the lack of an effective anti-SARS-CoV vaccine and specific antiviral drugs, the strict sanitary procedures proved to be sufficient to stop the SARS epidemic in June 2003. However, epidemic research has indicated that SARS-CoV-2 is transmitted in humans significantly more effectively than SARS-CoV; therefore, the COVID-19 pandemic continues to expand. This indicates that the so far anti-epidemic activities to control COVID-19 are insufficient. In the current review, the possibility of using interferon α (IFN-α) as a preventive agent of COVID-19 is discussed. The current data concerning anti-COVID-19 vaccines and specific drugs against SARS-CoV-2 are also discussed. The aim of the current review is to contribute to the introduction of a more efficient strategy in the protection of the human population against COVID-19.

Natural killer cell cytotoxicity and immunosuppressive cytokines (IL-10, TGF-beta1) in patients with gastric cancer.

Cytotoxic activity of NK cells was estimated as related to IL-10 and TGF-beta1 serum levels and Helicobacter pylori infection in gastric cancer patients. Moreover, we sought to determine whether human gastric adenocarcinoma cells in vitro release IL-10, TGF-beta1 or factor(s) affecting NK cytotoxicity. The studies were conducted on 42 patients with gastric cancer (14 with I-II stage-group 1; 28 with III-IV stage-group 2) and on 20 healthy volunteers. The cytotoxicity was tested on NK cells isolated from peripheral blood. IL-10 and TGF-beta1 levels were determined by ELISA. H. pylori was detected in cultures of gastric mucosa biopsies and in direct preparations. In 71.4% patients of group 1 NK cytotoxicity and IL-10 serum levels remained within a normal range while in 68% patients of group 2 a marked decrease was noted in cytotoxic function of NK cells, accompanied by increased levels of IL-10 in serum. In turn, in most patients of either group, independently of NK cytotoxicity and stage grouping in the patients, elevated serum levels of TGF-beta1 were detected. Presence of H. pylori infection manifested no relationship with NK cytotoxicity, IL-10, or the TGF-beta1 serum levels. In cultures of tumour cells presence of IL-10 and TGF-beta1 was demonstrated. Nevertheless, supernatants of the cultures did not change cytotoxic activity of NK cells. Development of gastric carcinoma is accompanied by markedly decreased cytotoxic function of NK cells and by elevated IL-10 and TGF-beta1 serum levels. Gastric carcinoma cells may release IL-10, the suppressive activity of which may in a secondary manner decrease NK cytotoxicity.

Antimicrobial resistance of Helicobacter pylori clinical strains in the last 10 years.

In the present work primary antimicrobial resistance was analyzed in clinical H. pylori strain isolates from adult patients from Polish Wielkopolska region within the last 10 years. Drug sensitivity was evaluated in a total of 142 H. pylori isolates, with 66 strains originating from years 1997/1998 forming group 1 and 76 strains isolated in 2007/2008 forming group 2. Sensitivity to amoxicillin, tetracycline, metronidazole and clarithromycin was determined by E-test. All strains were susceptible to amoxicillin and tetracycline. On the other hand, a high proportion of strains resistant to metronidazole was determined (36.4% in group 1 and 44.7% in group 2). In parallel, a growing tendency was discovered for resistance to clarithromycin (9.1% strains resistant in group 1 and 18.4% isolates resistant in group 2). The studies confirm the need for monitoring the drug resistance of Helicobacter pylori strains.

[Evaluation of the antagonistic effect of Lactobacillus acidophilus on clinical strains of Helicobacter pylori]. / Antagonistyczne oddzialywanie Lactobacillus acidophilus wobec klinicznych szczepów Helicobacter pylori.

The purpose of the study was to determine the antagonistic effect of Lactobacillus strains, isolated from saliva of healthy people on clinical strains of H. pylori. Two kinds of Lactobacillus strains were used in the tests i.e. strains producing hydrogen peroxide as well as strains not producing the metabolite. Clinical isolates of H. pylori were taken from the patients with confirmed duodenal and gastric ulcers. The evaluation of antagonistic effect between microorganisms was performed by using agar slab method. It was observed that Lactobacillus acidophilus had an antagonistic effect on growth of all strains of H. pylori tested. However, the particular Lactobacillus strains differed with respect to their inhibitory properties. Hydrogen peroxide did not have any significant impact on the inhibition of the growth of Helicobacter pylori.

[Mycobacterium avium subsp. paratuberculosis in inflammatory bowel diseases]. / Mycobacterium avium subsp. paratuberculosis w nieswoistych chorobach zapalnych jelit.

In the paper results were presented of a study on manifestation of infection with Mycobacterium avium subsp.paratuberculosis in 16 patients aged 15-42 years with Lesniowski-Crohn disease (group 1), in 20 patients aged 21-50 years with ulcerative colitis (group 2) and in 12 healthy individuals aged 23-60 years (group 3, control). All the ill patients were subjected to surgery, involving partial or total resection of large intestine, while individuals in group 3 (control) were subjected to colonoscopy with sampling of large intestine. Using mechanical/enzymatic technique DNA was extracted from the tissue material and was identified using PCR-ELISA technique (Mycobacterium paratuberculosis PCR; Institut Pourquier-France). Colour reaction was evoked using the TMB substrate. In the studies presence of Mycobacterium avium subsp. paratuberculosis was noted in 10 (62.5%) patients with Lesniowski-Crohn disease, in 5 (25%) patients with ulcerative colitis and in 1 patient 1 (8.3%) patient of the control group. The obtained results permit to suggest that Mycobacterium avium subsp. paratuberculosis bacteria participate in etiopathogenesis of Lesniowski-Crohn disease.

Epstein-Barr virus (EBV) infection and p53 protein expression in gastric carcinoma.

In the presented studies p53 protein expression was evaluated in samples of gastric carcinoma originating from 32 selected adult patients (with documented diagnosis of adenocarcinoma of the stomach and without the presence of Helicobacter pylori infection). Among the patients 14 individuals carried EBV-positive gastric carcinoma (group 1) while the 18 remaining patients carried EBV-negative gastric carcinoma (group 2). EBV infection was detected testing the tissue material for the presence of EBER by RNA in situ hybridization (ISH) and testing sera of the patients for EBV-specific antibodies. Expression of p53 protein was analysed using immunohistochemistry. Presence of p53 protein was noted in 9 (64.3%) cases of EBV-positive gastric cancer (group 1) and in 10 (55.5%) cases of EBV-negative gastric cancer (group 2). No significant differences were detected in the frequencies of p53 protein expression in the two studied groups. The results permit to conclude that abnormalities in p53 in gastric cancer are independent of EBV infection, even if EBV may participate in development of the tumour.

Expression of cagA, virB/D Complex and/or vacA Genes in Helicobacter pylori Strains Originating from Patients with Gastric Diseases.

In order to better understand pathogenicity of Helicobacter pylori, particularly in the context of its carcinogenic activity, we analysed expression of virulence genes: cagA, virB/D complex (virB4, virB7, virB8, virB9, virB10, virB11, virD4) and vacA in strains of the pathogen originating from persons with gastric diseases. The studies were conducted on 42 strains of H. pylori isolated from patients with histological diagnosis of non-atrophic gastritis-NAG (group 1, including subgroup 1 containing cagA+ isolates and subgroup 2 containing cagA- strains), multifocal atrophic gastritis-MAG (group 2) and gastric adenocarcinoma-GC (group 3). Expression of H. pylori genes was studied using microarray technology. In group 1, in all strains of H. pylori cagA+ (subgroup 1) high expression of the gene as well as of virB/D was disclosed, accompanied by moderate expression of vacA. In strains of subgroup 2 a moderate expression of vacA was detected. All strains in groups 2 and 3 carried cagA gene but they differed in its expression: a high expression was detected in isolates of group 2 and its hyperexpression in strains of group 3 (hypervirulent strains). In both groups high expression of virB/D and vacA was disclosed. Our results indicate that chronic active gastritis may be induced by both cagA+ strains of H. pylori, manifesting high expression of virB/D complex but moderate activity of vacA, and cagA- strains with moderate expression of vacA gene. On the other hand, in progression of gastric pathology and carcinogenesis linked to H. pylori a significant role was played by hypervirulent strains, manifesting a very high expression of cagA and high activity of virB/D and vacA genes.

Selected Factors of Innate Immunity in Healthy Individuals with S. aureus Nasal Carriage.

Nasal carriage of Staphylococcus aureus represents a well-defined factor of risk involving community and hospital-acquired infections. Recently a significance of several host factors has been pointed out and, in particular, of immune determinants in nasal S. aureus colonization. Therefore, this study aimed at analysis of manifestation involving manifestation in the nasal secretions of important components of the host innate immunity - human beta-defensin-2 (HBD-2), lysozyme (Ly), and interferon-gamma (IFN-γ) in healthy individuals and in persons with persistent carriage of S. aureus. The studies were conducted in two groups of healthy volunteers, encompassing non-carriers (group 1) or persistent carriers of S. aureus (group 2). Elisa assays were employed to evaluate levels of HBD-2, Ly, and IFN-γ in nasal secretions of the examined donors. In S. aureus carriers a significant variability of HBD-2 levels was detected, corresponding to, respectively, the high (averaging at 1.46 ng/ml) and the low (averaging at 0.13 ng/ml) secretory response of the defensin. The level of Ly in S. aureus carriers averaged at 1.46 µg/ml and it manifested no significant difference as compared to that noted in non-carriers. In turn, concentrations of IFN-γ in nasal secretions in the group of carriers of S. aureus amounted on the average to 81.7 pg/ml and they were 1.3-fold higher that in the group of non-carriers. The obtained results allow to conclude that IFN-γ secretion by the nasal cavity-colonizing S. aureus remains quantitatively insufficient to eliminate the pathogen. Nevertheless, a significant increase in levels of this host factor may be important for restriction of the staphylococcal colonization and protection against development of an invasive infection. In turn, the role of HBD-2 and Ly in inactivation of the colonizing S. aureus remains doubtful.

Effects of IL-12 and IL-18 on HBcAg-specific cytokine production by CD4 T lymphocytes of children with chronic hepatitis B infection.

The influence of IL-12 and IL-18 was evaluated on hepatitis B core antigen (HBcAg)-specific cytokine production (IFN-gamma, IL-4, IL-5 and IL-10) by CD4 T lymphocytes isolated from peripheral blood of children with chronic hepatitis B. CD4 T cells were isolated from peripheral blood of 20 children with chronic active hepatitis B, cultured for 48h in presence of rHBcAg and of co-stimulators, IL-12 or IL-18 or IL-12+IL-18 or in their absence (control). Production of studied cytokines was examined using the ELISPOT assay. Co-stimulation with IL-12 or IL-18 was found to significantly augment the HBcAg-specific secretion of IFN-gamma. However, the most pronounced stimulatory effect was observed in the presence of IL-12+IL-18 and resulted in peak levels of IFN-gamma production. The obtained results allowed concluding that the anti-HBV activity of Th1 lymphocytes is strongly induced by IL-12+IL-18 and may contribute to viral clearance in children with chronic hepatitis B infection.

Evaluation of antimicrobial resistance of Helicobacter pylori in the last 15 years in West Poland.

Increasing resistance to drugs represents a serious problem in treatment of infections with Helicobacter pylori, providing cause of frequent therapeutic failures. Present study aimed at analysis of changes in resistance of H. pylori to antibiotics in West Poland within the recent 15 years. 108 strains of H. pylori were analysed, isolated from gastric mucosa of adult patients. Group 1 involved 66 strains isolated in years of 1998/1999. Group 2 comprised 42 isolates obtained in years of 2013/2014. Susceptibility to amoxicillin (AMX), clarithromycin (CL), tetracycline (TC) and metronidazole (MTZ) was determined by E-test (AB Biodisc). All strains on both studied groups were susceptible to AMX. In group 1 all strains proved to be susceptible to TC, while 9% and 36% of tested strains were resistant to CL and MTZ, respectively. By contrast, in group 2, 31% and 83% of strains were resistant to CL and MTZ, respectively. In parallel, 14% strains were found to be resistant to TC (according to EUCAST interpretations). In West Poland, within recent 15 years a dramatic increase was noted in H. pylori strains resistant to metronidazole. In parallel, a significant increase was noted in proportion of strains resistant to clarithromycin.

HBcAg-specific cytokine production by CD4 T lymphocytes of children with acute and chronic hepatitis B.

In the presented studies HBcAg-specific cytokine production (IFN-gamma, IL-2, IL-4, IL-5 and IL-10) was evaluated, by Th lymphocytes isolated from peripheral blood of children with acute or chronic B hepatitis. Moreover, effect of IL-10 neutralization was examined on HBcAg-induced secretory response of Th lymphocytes obtained from children with chronic B hepatitis. The studies were performed on 12 children with acute self-limited B hepatitis and 20 children with chronic active B hepatitis. CD4 T cells were isolated from peripheral blood of the patients, cultured for 48h in presence of rHBcAg or in its absence (control). Production of studied cytokines was monitored using ELISPOT and ELISE assays. The course of acute self-limited B hepatitis was associated with preferential Th1-type response, manifested by elevated production of IFN-gamma and IL-2. On the other hand, in chronic B hepatitis a diminished response to HBcAg of both Th1 and Th2 types was disclosed, characterized by very low secretion of IFN-gamma, IL-2, IL-4 and IL-5. In parallel, preferential antigen-specific production of IL-10 was noted and its suppressive effect on HBcAg-induced response of Th1 cells. The results permitted to conclude that in children with acute self-limited B hepatitis preferential HBcAg-specific activation of Th1 lymphocytes may be of significance for efficient anti-HBV immune response. On the other hand, development of chronic B infection in children seems to be determined by disturbed HBcAg-specific functions of both Th1 and Th2 cells whereas activity of the disease may be controlled by anti-inflammatory response of antigen-presenting cells and/or of regulatory CD4 T lymphocytes, involving IL-10 production.

Human papillomavirus (HPV) and Epstein-Barr virus (EBV) cervical infections in women with normal and abnormal cytology.

In 48 adult women, subdivided into group 1 with no cervical intraepithelial neoplasia (CIN-negative) and group 2 (CIN-positive), endocervical scrapes were tested for the presence EBV DNA and HPV DNA using PCR-ELISA. In addition, attempts were made to detect HPV 16 and HPV 18 using other PCR amplification techniques. In parallel, in biopsies of uterine cervix obtained from group 2 patients, presence of EBER was documented by RNA in situ hybridization (ISH). Sera of all patients were tested for anti-EBV antibodies. In group 1, presence of EBV DNA was noted in the material obtained from 8 women (30.8%), while HPV DNA was detected in 2 women (7.7%). In group 2, EBV DNA was present in the material obtained from 11 patients (50%), including 7 (31.8%) with HPV DNA also identified. In 5 women (22.7%) of group 2 only HPV DNA was detected. The identifical HPV DNA in all cases belonged to HPV 16 type. Both in group 1 and in group 2, all patients were found to carry serum IgG-anti-VCA and IgG-anti-EBNA antibodies. The results allow to conclude that, co-infection with EBV and HPV 16 may be of cervical significance in etiopathogenesis of uterine cervical cancer.

[Detection of the expression of extended-spectrum beta-lactamases (ESBL) in clinical strains of Klebsiella pneumoniae and Escherichia coli: comparison of E-test and two-disc methods]. / Wykrywanie ekspresji beta-laktamaz o rozszerzonym spektrum substratowym (ESBL) wsród klinicznych szczepów Klebsiella pneumoniae i Escherichia coli; porównanie E-testu i dwóch testów krazkowych.

The aim of this study was to compare the effectiveness of E-test and two disc methods applied for the detection of extended spectrum beta-lactamases. All strains were tested by E-test, by double-disc synergy test (DDST) according to Jarlier (cefotaxim, ceftazidim, aztreonam and clavulanic acid) and also by disc test according to Appleton (cefpodoxime and cefpodoxime with clavulanic acid, CPD and CD01 disc). We tested 148 clinical strains of E. coli and 78 strains of K. Pneumoniae. In case of K. pneumoniae, the activity of the ESBLs was detected among 30 strains--both in E-test, Jarlier test and Appleton test. Among E. coli, four strains were found ESBL-positive in the test according to Jarlier but only three strain of these when E-test and Appleton test was used. The results of investigations performed suggest, that E-test and disc methods according both Jarlier and Appleton have the same effectiveness in detection ESBLs among K. pneumoniae strains. However, in case of E. coli, interpretation of results may present a problem.

Effect of novobiocin on the viability of human gingival fibroblasts (HGF-1).

BACKGROUND: Novobiocin is a coumarin antibiotic, which affects also eukaryotic cells inhibiting activity of Heat shock protein 90 (Hsp90). The Hsp90 represents a molecular chaperone critical for stabilization and activation of many proteins, particularly oncoproteins that drive cancer progression. Currently, Hsp90 inhibitors focus a significant attention since they form a potentially new class of drugs in therapy of cancer. However, in the process of tumorigenesis a significant role is played also by the microenvironment of the tumour, and, in particular, by cancer-associated fibroblasts (CAFs). This study aimed at examination of the effect played by novobiocin on viability of human gingival fibroblasts (HGF-1). METHODS: The studies were conducted using 24 h cultures of human gingival fibroblasts - HGF-1 (CRL-2014) in Chamber Slides, in presence of 0.1, 0.5, 1.0, 2.5 or 5.0 mM novobiocin. Cell viability was evaluated using fluorescence test, ATP assay and LDH release. RESULTS: Viability of HGF-1 was drastically reduced after 5 hour treatment with novobiocin in concentrations of 1 mM or higher. In turn, the percentage of LDH-releasing cells after 5 h did not differ from control value although it significantly increased after 10 h incubation with 1 mM and continued to increase till the 20th hour. CONCLUSIONS: The obtained data indicate that novobiocin may induce death of human gingival fibroblasts. Therefore, application of the Hsp90 inhibitor in neoplastic therapy seems controversial: on one hand novobiocin reduces tumour-associated CAFs but, on the other, it may induce a significant destruction of periodontium.