Porphyromonas gingivalis Lipopolysaccharide Induces a Pro-inflammatory Human Gingival Fibroblast Phenotype.

Human gingival fibroblasts (HGFs) are the major constituents of the gingival tissues responsible for the synthesis and degradation of the connective tissue while actively participating in immune reactions and inflammation. The aim of this study was to test the impact of lipopolysaccharide (LPS) from Porphyromonas gingivalis (P. gingivalis) on human gingival fibroblasts. Human gingival fibroblasts were treated with different P. gingivalis LPS concentrations. Cell survival rate was evaluated with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) after 24 h. Cell proliferation was determined by counting cells on days 3 and 12. Expression of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMPs), and pro-inflammatory cytokine transcripts in HGFs was determined by quantitative PCR (Q-PCR) analysis on days 3 and 8. P. gingivalis LPS decreased cell proliferation on day 3 (p < 0.05) compared to the control group without significantly impacting the cell survival (p > 0.05).The experiments showed that P. gingivalis LPS dose-dependently and differentially modulated the expression of MMP-1, 2, and 3 and TIMP-1 and 2 on days 3 and 8. TIMP-1 expression was significantly induced in P. gingivalis LPS-treated cells while TIMP-2 was increased in response to 10 and 30 ng/ml of LPS on day 3. P. gingivalis LPS induced up-regulation of MMP-1/TIMP-1 ratio on day 3 and increased MMP-2/TIMP-2 ratio on day 8 dose-dependently. Expression of interleukin (IL)-6 and IL-8 was stimulated at higher concentrations (1000 and 3000 ng/ml) of LPS. These findings demonstrate that P. gingivalis LPS suppresses cell proliferation and leads to increased pro-inflammatory changes in HGFs, suggesting that P. gingivalis LPS-induced modification of phenotypic and inflammatory characteristics in HGF could potentially be a pathogenic mechanism underlying the tissue destruction.

Assessment of antimutagenic action of Celtis glabrata Steven ex Planch. (Cannabaceae) extracts against base pair exchange and frame shift mutations on Salmonella typhimurium TA98 and TA100 strains by Ames test.

CONTEXT: Celtis glabrata is used in Turkey for the treatment of various health disorders. OBJECTIVE: The acetone, chloroform, ethanol, and methanol extracts of C. glabrata leaf, fruit, and seed were investigated to evaluate their antimutagenic activities. MATERIAL AND METHODS: The antimutagenicity of these extracts was determined by Ames test against mutagens (4-nitro-O-phenylenediamine, 2-aminofluorene (2-AF), and sodium azide (SA)). The extracts were used at concentrations between 5 and 0.005 mg/plate. RESULTS: The ethanol extracts of leaves exhibited strong antimutagenicity (70%) against 2-AF with S9 at 5 mg/plate on TA98. But methanol (61%, 53%) and acetone (53%, 52%) also revealed strong inhibition rates at concentrations of ≥ 0.5 mg/plate. Among the extracts, the highest activity (96%) was obtained from acetone extract against SA without S9, followed by chloroform extract (91%) at a dose of 5 mg/plate on TA100 with S9. Ethanol (without S9) and chloroform (with S9) extracts showed strong antimutagenicity at all doses. Exception of chloroform and acetone (without S9), all fruit extracts (with/without S9) manifested strong antimutagenicity at doses of ≥ 0.5 mg/plate on TA98 strain. Ethanol extracts revealed 68% inhibition against 2-AF on TA98. Acetone and ethanol extracts manifested 84% and 82% inhibition against SA on TA100, respectively. All the extracts of seeds revealed strong inhibition against 2-AF at ≥ 0.5 mg/plate doses on TA98, but acetone extract showed excellent antimutagenicity (94%). Moreover, the chloroform (74, 73, 63, 54%), acetone (74, 72, 70, 65%) and methanol (74, 67, 63, 61%) extracts of seeds revealed strong antimutagenic activity on TA100 against SA with S9. DISCUSSION AND CONCLUSION: This plant may be natural source of antimutagenic agents.

Characterization of Klebsiella pneumoniae strains isolated from urinary tract infections: detection of ESBL characteristics, antibiotic susceptibility and RAPD genotyping.

In this study, a hundred Klebsiella pneumoniae strains isolated from urinary tract infections were evaluated in terms of genotyping, susceptibility to certain antibiotics and detection of extended spectrum of beta lactamase (ESBL) production. The random amplified polymorphic DNA (RAPD-PCR) method was used to identify the genetic differentiation of K. pneumoniae isolates. A total of 26 different DNA bands ranging between 334 bp and 28033 bp were detected among the strains. It was found that 100 K. pneumoniae strains revealed 11 different RAPD profiles. Antibiotic susceptibility tests were conducted using a disc diffusion method against 16 antibiotics. Fifty-five different resistance profiles were determined among the strains. ESBL-productions of the strains were determined by the double disc synergy test (DDST) and ESBL E-test methods. ESBL production rates among the strains were found to be 55% by E-test method and 45% by DDST method. While ESBL-producing K. pneumoniae strains showed the greatest resistance to penicillin G (100%), followed by piperacillin (92.7%) and erythromycin (85.4%),the resistance rates of non ESBLproducing strains to those antibiotics were determined as 97.8%, 88.8% and 88.8%, respectively. Both groups of strains showed the highest sensitivity to meropenem. Based on the results obtained from the study, it was concluded that the detection of ESBL-producing strains by the E-test method was more sensitive than by the DDST method. Phenotypic and genotypic identification methods should be used together to detect ESBL presence. The RAPD-PCR method alone will not be adequate in the genotyping of the strains and alternative DNA-based methods should be used.

Pulsed-field gel electrophoresis typing, antibiotic resistance, and plasmid profiles of Escherichia coli strains isolated from foods.

Bacterial contamination in foods and antimicrobial resistance levels of common pathogenic strains causing food-borne disease are important in human health. Thus, typing technologies are important tools to determine primary sources of bacterial contamination. In this study, 40 Escherichia coli strains isolated from 85 food samples were evaluated in terms of genetic diversity, susceptibility to certain antibiotics, and plasmid profiles. Pulsed-field gel electrophoresis was used to identify the genetic relations of E. coli isolates. It was determined that the 40 E. coli strains revealed 32 different pulsotypes represented by 6 subtypes. Antibiotic susceptibility tests conducted by using a disc diffusion method against 15 antibiotics showed that although the isolates revealed 14 different types of resistance profiles, the strains showed the greatest resistance to ampicillin (77.5%), followed by ticarcillin-clavulanic acid (30%), tetracycline (22.5%), and cephalothin (14.5%). Plasmid isolations studies of the strains conducted by the method of alkaline lysis revealed that 18 (45%) of 40 E. coli strains contain 31 different plasmid bands ranging between 64.4 and 1 kb. The results showed that PFGE was a powerful method in tracking sources of food contamination and that the antibiotic resistance levels of food isolates were high and should be monitored.