| 1. |
- Almståhl, Annica, 1973, et al.
(författare)
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Acid-producing capacity from sugars and sugar alcohols among Lactobacillus isolates collected in connection with radiation therapy
- 2017
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Ingår i: Archives of Oral Biology. - : Elsevier BV. - 0003-9969. ; 84, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- Objective To investigate the acid-producing capacity from sugars and sugar alcohols of oral Lactobacillus collected in connection with radiation therapy (RT) to the head and neck region. Design Lactobacillus were collected from the tongue, buccal mucosa and supragingival plaque in 24 patients before, during, and after RT. The acid-producing capacity of Lactobacillus isolates (n = 211) was analyzed using a colorimetric fermentation test in microtiter plates. Solutions containing 2% sugars (sucrose, glucose, fructose, lactose) or sugar-alcohols (sorbitol and xylitol) were used. After 24 h of incubation, bacterial acid-producing capacity was determined as strong (pH < 5), weak (pH ≥5–≤ 6) or low/absent (pH > 6). Data regarding intake frequency of sugar-rich products and products with sugar-alcohols was collected. Results The highest acid-producing capacity using the sugars was seen for isolates collected during RT. Sorbitol was fermented to a higher extent during and post RT, especially among isolates from plaque. Lactobacillus fermenting xylitol showed the highest acid-producing capacity during RT (p < 0.05). No statistically significant correlations between stimulated whole salivary secretion rate and acid-producing capacity, or between the intake frequency of sugar-rich products or sugar-alcohol containing products and Lactobacillus acid-producing capacity, were found. Conclusion The results suggest that Lactobacillus isolates, collected from the tongue, buccal mucosa and supragingival plaque, have a higher acid-producing capacity using sugars and sugar-alcohols during RT than one year post RT. © 2017 Elsevier Ltd
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| 2. |
- Basic, Amina, et al.
(författare)
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Antibiotic resistance among Aerobic Gram-Negative Bacilli isolated from patients with oral inflammatory dysbiotic conditions-a retrospective study
- 2024
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Ingår i: FRONTIERS IN DENTAL MEDICINE. - 2673-4915. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Aerobic Gram-Negative Bacilli (AGNB) are not part of the resident oral microflora but are occasionally found in high abundance under inflammatory dysbiotic conditions at various oral niches. The aim of the present study was to investigate the identity and antibiotic susceptibility of AGNB isolated from patients in Sweden with mucosal lesions, periodontitis, and peri-implantitis, with special attention to antibiotic resistance and on the presence of phenotypic Extended Spectrum Beta-Lactamase (ESBL) isolates. Materials and methods: Microbiolgical samples were harvested from 211 patients in total, experiencing mucosal lesions (N = 113), periodontitis (N = 62), or peri-implantitis (N = 36). The growth of AGNB's was semiquantified by selective and non-selective culture and the strains were isolated, identified, and tested for antibiotic susceptibility. A total of 251 AGNB strains, occurring in moderate to heavy growth (>100 CFU/ml sample), indicating a dysbiotic microbiota, were identified. The disc diffusion method was used for screening of the antibiotic susceptibility of the isolates. Phenotypic identification of ESBL isolates was based on resistance to ceftazidime and/or cefotaxime. Results: The most commonly detected AGNB isolates in oral inflammatory dysbiotic conditions were fermentative species belonging to Enterobacteriaceae e.g. Citrobacter spp., Enterobacter spp., Escherichia coli, Klebsiella spp, and the non-fermentative environmental Burkholderia cepacia, Pseudomonas spp., and Stenotrophomonas maltophilia. No clear trends were seen in frequency of the various species in samples from mucosal lesions, severe periodontitis, and peri-implantitis cases. The 138 Enterobacteriaceae isolates and 113 environmental AGNB isolated showed a high antibiotic resistance in general against antibiotics commonly used in dentistry (Amoxicillin, Amoxicillin + Clavulanic acid, Ampicillin, Clindamycin, Doxycycline, Erythromycin, Oxacillin, PenicillinV, and Tetracycline). The majority of these isolates were susceptible to ciprofloxacin. Ten isolates (4.1%) were phenotypically classified as ESBL positive. The ESBL isolates were predominantly found among isolates of S. maltophilia, while only one ESBL positive isolate was found among Enterobacteriaceae. Conclusions: Phenotypically identified ESBL isolates can occasionally be present among oral AGNB strains isolated in abundance from the dysbiotic microbiota occurring in cases with oral mucosal lesions, severe periodontitis, or peri-implantitis.
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| 3. |
- Basic, Amina, et al.
(författare)
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Estimation of bacterial hydrogen sulfide production in vitro.
- 2015
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Ingår i: Journal of oral microbiology. - : Informa UK Limited. - 2000-2297. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Oral bacterial hydrogen sulfide (H2S) production was estimated comparing two different colorimetric methods in microtiter plate format. High H2S production was seen for Fusobacterium spp., Treponema denticola, and Prevotella tannerae, associated with periodontal disease. The production differed between the methods indicating that H2S production may follow different pathways.
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| 4. |
- Basic, Amina, et al.
(författare)
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H2S mediates increased interleukin (IL)-1β and IL-18 production in leukocytes from patients with periodontitis
- 2019
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Ingår i: Journal of Oral Microbiology. - : Informa UK Limited. - 2000-2297. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- - Background: The mechanisms involved in the interplay between the bacteria and the host cells in periodontitis are not fully understood. Aim: To investigate the effect of the bacterial metabolite H2S on the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 from periodontitis patients and healthy controls, and to evaluate the composition of the subgingival microbiota with its capacity to produce H2S. Methods: Subgingival bacterial samples from patients with periodontitis (N=32) and healthy controls (N=32) were investigated for H2S production and bacterial composition. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence/absence of 1mM H2S for 24h and cytokine concentrations were measured. Results: Subgingival plaque from periodontitis patients had more H2S producing bacteria and produced more H2S, than healthy controls. PBMCs exposed to H2S secreted significantly more IL-1ß and IL-18 (p<0.0001) than untreated control PBMCs from both groups. PBMCs from the periodontitis patients secreted higher levels of the cytokines, both spontaneously (IL-1ß p=0.0001; IL-18 p=0.09) and after exposure to H2S (IL-1ß p=0.03; IL-18 p=0.04), which is a new finding not previously reported. Conclusions: H2S, from the subgingival microbiota, can contribute to a host inflammatory response through secretion of the pro-inflammatory cytokines IL-1β and IL-18. Since this response differs between individuals, it may also reflect the susceptibility of the host to develop periodontitis. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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| 5. |
- Basic, Amina, et al.
(författare)
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Hydrogen sulfide exposure induces NLRP3 inflammasomedependent IL-1 beta and IL-18 secretion in human mononuclear leukocytes in vitro
- 2017
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Ingår i: Clinical and Experimental Dental Research. - : Wiley. - 2057-4347. ; 3:3, s. 115-120
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to investigate if hydrogen sulfide (H2S) induces the formation of the NLRP3 inflammasome and subsequent IL-1 beta and IL-18 secretion in human peripheral blood mononuclear cells (PBMCs) and in the human monocyte cell line THP1. Bacterial production of H2S has been suggested to participate in the inflammatory host response in periodontitis pathogenesis. H2S is a toxic gas with pro-inflammatory properties. It is produced by bacterial degradation of sulfur-containing amino acids, for example, cysteine. We hypothesize that H2S affects the inflammatory host response by inducing formation of the NLRP3 inflammasome and thereby causes the secretion of IL-1 beta and IL-18. PBMCs from eight healthy blood donors, the human monocyte cell line THP1 Null, and two variants of the THP1 cell line unable to form the NLRP3 inflammasome were cultured in the presence or absence of 1 mM sodium hydrosulfide (NaHS) in 24-well plates at 37 degrees C for 24 hr. Supernatants were collected and the IL-1 beta and IL-18 concentrations were measured with DuoSet ELISA Development kit. PBMCs exposed to NaHS produced more IL-1 beta and IL-18 than unexposed control cells (p = .023 and p = .008, respectively). An increase of extracellular potassium ions (K+) inhibited the secretion of IL-1 beta and IL-18 (p = .008). Further, NaHS triggered the secretion of IL-1 beta and IL-18 in human THP1-Null monocytes (p = .0006 and p = .002, respectively), while the NaHS-dependent secretion was reduced in the monocyte cell lines unable to form the NLRP3 inflammasome. Hence, the results suggest that NaHS induces the formation of the NLRP3 inflammasome and thus the secretion of IL-1 beta and IL-18. Enhanced NLRP3 inflammasome-dependent secretion of IL-1 beta and IL-18 in human mononuclear leukocytes exposed to NaHS in vitro is reported. This may be a mode for H2S to contribute to the inflammatory host response and pathogenesis of periodontal disease.
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| 6. |
- Basic, Amina, et al.
(författare)
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Hydrogen sulfide production from subgingival plaque samples.
- 2015
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Ingår i: Anaerobe. - : Elsevier BV. - 1095-8274 .- 1075-9964. ; 35:Part A, s. 21-27
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Tidskriftsartikel (refereegranskat)abstract
- Periodontitis is a polymicrobial anaerobe infection. Little is known about the dysbiotic microbiota and the role of bacterial metabolites in the disease process. It is suggested that the production of certain waste products in the proteolytic metabolism may work as markers for disease severity. Hydrogen sulfide (H2S) is a gas produced by degradation of proteins in the subgingival pocket. It is highly toxic and believed to have pro-inflammatory properties. We aimed to study H2S production from subgingival plaque samples in relation to disease severity in subjects with natural development of the disease, using a colorimetric method based on bismuth precipitation. In remote areas of northern Thailand, adults with poor oral hygiene habits and a natural development of periodontal disease were examined for their oral health status. H2S production was measured with the bismuth method and subgingival plaque samples were analyzed for the presence of 20 bacterial species with the checkerboard DNA-DNA hybridization technique. In total, 43 subjects were examined (age 40-60 years, mean PI 95±6.6%). Fifty-six percent had moderate periodontal breakdown (CAL>3<7mm) and 35% had severe periodontal breakdown (CAL>7mm) on at least one site. Parvimonas micra, Filifactor alocis, Porphyromonas endodontalis and Fusobacterium nucleatum were frequently detected. H2S production could not be correlated to periodontal disease severity (PPD or CAL at sampled sites) or to a specific bacterial composition. Site 21 had statistically lower production of H2S (p=0.02) compared to 16 and 46. Betel nut chewers had statistically significant lower H2S production (p=0.01) than non-chewers. Rapid detection and estimation of subgingival H2S production capacity was easily and reliably tested by the colorimetric bismuth sulfide precipitation method. H2S may be a valuable clinical marker for degradation of proteins in the subgingival pocket.
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| 7. |
- Basic, Amina
(författare)
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Importance of bacterial hydrogen sulfide in the pathogenesis of periodontal diseases
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Hydrogen sulfide (H2S) is one of many end-products of the proteolytic activities in the subgingival microbiota in patients with periodontal diseases, such as gingivitis and periodontitis. Although H2S is generally regarded as toxic, the mechanisms that underlie its production and its effects on human cells and tissues are poorly understood. Therefore, the role of H2S in the pathogenesis of periodontal diseases was investigated. Two colorimetric methods, the bismuth test (BT) and the methylene blue (MB) method, were used to estimate the amounts of H2S produced by the bacteria in vitro and ex vivo (Papers I, II and V). Oral bacteria, e.g., Fusobacterium spp., Porphyromonas gingivalis and Treponema denticola, were found to have strong capacities to degrade cysteine and produce H2S in vitro (Paper I). The Fusobacterium spp. were found to express several enzymes that are involved in the production of H2S. The expression patterns of the different enzymes varied among Fusobacterium subspecies and strains (Paper III). In an ex vivo experiment using BT, we showed that the subgingival plaques of subjects (N=43) with poor oral hygiene had the capacity to produce H2S (Paper II). High levels of periodontitis-associated bacteria were detected, and the BT values reflected the proteolytic activities of the bacteria and gingival inflammation rather than disease progression and periodontitis. A correlation between a positive BT and gingival inflammation was confirmed in Paper V, where H2S-producing bacteria were significantly more prevalent in the subgingival pockets of periodontitis patients (N=32) than of healthy controls (N=32), which indicates potent bacterial proteolytic activities in the untreated deep periodontal pockets. Paper IV described how the peripheral blood mononuclear cells (PBMCs) of blood donors and a monocytic cell line increased their secretion of the pro-inflammatory cytokines IL-1β and IL-18 in vitro when exposed to the H2S-donor sodium hydrosulfide (NaHS). This secretion was shown to be mediated by the NLRP3 inflammasome. These results were verified in Paper V, where the PBMCs of periodontitis patients and healthy controls secreted significantly higher levels of IL-1β and IL-18 when exposed to NaHS. In addition, both unexposed and exposed PBMCs of the periodontitis patients secreted higher levels of the two cytokines than the corresponding cells of healthy controls. These results suggest that the susceptibility of the host to develop disease can be attributed in part to enhanced secretion of pro-inflammatory cytokines following exposure to bacterial metabolites, such as H2S. In summary, toxic bacterial metabolites, such as H2S, may play an important role by affecting the cells of the host immune system, thereby inducing and sustaining gingival inflammation.
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| 8. |
- Basic, Amina, et al.
(författare)
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Microbial metabolites in the pathogenesis of periodontal diseases: a narrative review
- 2023
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Ingår i: Frontiers in Oral Health. - 2673-4842. ; 4
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Forskningsöversikt (refereegranskat)abstract
- The purpose of this narrative review is to highlight the importance of microbial metabolites in the pathogenesis of periodontal diseases. These diseases, involving gingivitis and periodontitis are inflammatory conditions initiated and maintained by the polymicrobial dental plaque/biofilm. Gingivitis is a reversible inflammatory condition while periodontitis involves also irreversible destruction of the periodontal tissues including the alveolar bone. The inflammatory response of the host is a natural reaction to the formation of plaque and the continuous release of metabolic waste products. The microorganisms grow in a nutritious and shielded niche in the periodontal pocket, protected from natural cleaning forces such as saliva. It is a paradox that the consequences of the enhanced inflammatory reaction also enable more slow-growing, fastidious, anaerobic bacteria, with often complex metabolic pathways, to colonize and thrive. Based on complex food chains, nutrient networks and bacterial interactions, a diverse microbial community is formed and established in the gingival pocket. This microbiota is dominated by anaerobic, often motile, Gram-negatives with proteolytic metabolism. Although this alternation in bacterial composition often is considered pathologic, it is a natural development that is promoted by ecological factors and not necessarily a true "dysbiosis". Normal commensals are adapting to the gingival crevice when tooth cleaning procedures are absent. The proteolytic metabolism is highly complex and involves a number of metabolic pathways with production of a cascade of metabolites in an unspecific manner. The metabolites involve short chain fatty acids (SCFAs; formic, acetic, propionic, butyric, and valeric acid), amines (indole, scatole, cadaverine, putrescine, spermine, spermidine) and gases (NH3, CO, NO, H2S, H-2). A homeostatic condition is often present between the colonizers and the host response, where continuous metabolic fluctuations are balanced by the inflammatory response. While it is well established that the effect of the dental biofilm on the host response and tissue repair is mediated by microbial metabolites, the mechanisms behind the tissue destruction (loss of clinical attachment and bone) are still poorly understood. Studies addressing the functions of the microbiota, the metabolites, and how they interplay with host tissues and cells, are therefore warranted.
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| 9. |
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| 10. |
- Basic, Amina, et al.
(författare)
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The proteins of Fusobacterium spp. involved in hydrogen sulfide production from L-cysteine
- 2017
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Ingår i: Bmc Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 17:61
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Tidskriftsartikel (refereegranskat)abstract
- Background: Hydrogen sulfide (H2S) is a toxic foul-smelling gas produced by subgingival biofilms in patients with periodontal disease and is suggested to be part of the pathogenesis of the disease. We studied the H2S-producing protein expression of bacterial strains associated with periodontal disease. Further, we examined the effect of a cysteine-rich growth environment on the synthesis of intracellular enzymes in F. nucleatum polymorphum ATCC 10953. The proteins were subjected to one-dimensional (1DE) and two-dimensional (2DE) gel electrophoresis An in-gel activity assay was used to detect the H2S-producing enzymes; Sulfide from H2S, produced by the enzymes in the gel, reacted with bismuth forming bismuth sulfide, illustrated as brown bands (1D) or spots (2D) in the gel. The discovered proteins were identified with liquid chromatography - tandem mass spectrometry (LC-MS/MS). Results: Cysteine synthase and proteins involved in the production of the coenzyme pyridoxal 5'phosphate (that catalyzes the production of H2S) were frequently found among the discovered enzymes. Interestingly, a higher expression of H2S-producing enzymes was detected from bacteria incubated without cysteine prior to the experiment. Conclusions: Numerous enzymes, identified as cysteine synthase, were involved in the production of H2S from cysteine and the expression varied among Fusobacterium spp. and strains. No enzymes were detected with the in-gel activity assay among the other periodontitis-associated bacteria tested. The expression of the H2S-producing enzymes was dependent on environmental conditions such as cysteine concentration and pH but less dependent on the presence of serum and hemin.
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