China
Africa
Explore chapters and articles related to this topic
Biology of Acinetobacter spp.
Published in E. Bergogne-Bénézin, M.L. Joly-Guillou, K.J. Towner, Acinetobacter, 2020
Bergey’s Manual of Systematic Bacteriology classified the genus Acinetobacter in the family Neisseriaceae (Juni, 1984), with one species, A. calcoaceticus, comprising two varieties, var. anitratus (formerly Herellea vaginicola) and var. Iwoffii (formerly Mima polymorpha). More recent taxonomic developments have resulted in the proposal that members of the genus should be classified in the new family Moraxellaceae, which includes Moraxella, Acinetobacter, Psychrobacter and related organisms (Rossau et al., 1991), and which constitutes a discrete phylometric branch in superfamily II of the Proteobacteria on the basis of 16S rRNA studies and rRNA:DNA hybridisation assays (van Landschoot et al., 1986; Rossau et al., 1989).
Biological behavior of titanium, zirconia or PEEK dental implant-abutments
Published in J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares, Biodental Engineering V, 2019
M.B. Sordi, S.N.D. Sarwer-Foner, F.H. Schünemann, K. Apaza-Bedoya, G.M.P. Juanito, B. Henriques, B. Henriques, R.S. Magini, C.A.M. Benfatti
Usually, when comparing different materials, the variable roughness is eliminated to maintain the homogeneity of the groups at a Ra of about 0.2 mm (Avila et al. 2016, Esfahanizadeh et al. 2016). Ti and Zr are hydrophobic materials. Hydro-phobic attractive forces and electrostatic charge interactions between surfaces and bacteria play a key role in biofilm formation. Most bacteria have many ionizable groups on their surfaces, which confer a negative charge, particularly during the early stationary phase of bacterial growth. However, the charge that is present on the surface of some types of bacteria can create a hydrophobic effect via nonpolar molecules and result in an affinity for other hydrophobic surfaces, such as Ti and Zr. This characteristic explains why some bacterial species preferentially interact with certain materials and why the findings reported in the literature are inconsistent depending on the type of bacterial species assessed (Avila et al. 2016b). Interestingly, an in vitro study suggested that roughness and surface free energy did not influence the bacterial adhesion on Ti and Zr disks. Moreover, the rough surfaces provided favorable properties in terms of cell adhesion of fibroblasts—but not of epithelial cells, especially on Zr than on Ti disks (Rigolin et al. 2017). A clinical study evaluated individuals with Ti or Zr implant-abutments. In both materials, the most prevalent species were Gram-negative bacteria belonging mainly to the phylum Proteobacteira, which includes the Neisseriaceae and Campylobacteraceae families, followed by the phyla Firmicutes and Actinobacteria and Bacteroidetes. Pathogenic and non-pathogenic species were detected colonizing oral sites in both materials. Titanium-related sites presented the highest total microbial count and higher counts of pathogenic species (Nascimento et al. 2016). Clinically, mean probing depths around Ti abutments were slightly deeper than around Zr abutments after 3 months (van Brakel et al. 2011).
Initiation and progression of Early-Stage microbial-driven membrane fouling in membrane bioreactors: a review
Published in Biofouling, 2023
Yuya Takimoto, Toru Miwa, Masashi Hatamoto
Neisseriaceae, Parachlamydia, and Arcobacter were more abundant in the initial biofilm than in the bulk sludge (Hansen et al. 2021; Miwa et al. 2021). Although these bacteria were not abundant in the bulk sludge, they were abundant in the biofilm communities and followed a parasitic or symbiotic lifestyle. In particular, the abundance of planktonic Arcobacter was high in municipal wastewater and could not be reduced by activated sludge processes (Kristensen et al. 2020). Therefore, free-living or planktonic bacteria, which originate from the influent and detach from bulk sludge, may play significant roles as ‘true pioneers’ in initial biofilm formation. Additionally, because many studies have applied 16S rRNA gene sequencing, further research should focus on the remaining DNA in dead cells in biofilm samples to identify pioneers. Thus, in future studies, RNA or live cell-probed DNA should be extracted and applied for the analysis of microbial communities in the initial biofilm to select active cells in the biofilm. In addition, future studies should focus on the hidden effects of bacterial cells in SMP and EPS fractions. The bacterial cells accounted for SMP and EPSs may be attached to the membrane surface, forming early-stage biofilms.
Feasibility of oral microbiome profiles associated with oral squamous cell carcinoma
Published in Journal of Oral Microbiology, 2022
Kengo Hashimoto, Dai Shimizu, Sei Ueda, Satoru Miyabe, Ichiro Oh-Iwa, Toru Nagao, Kazuo Shimozato, Shuji Nomoto
Sequence data of bacterial DNA from saliva samples corresponded to a total of 11 phyla, 29 class, 51 order, 94 family and 130 genera. The predominant phyla were Bacteroidetes (29.5%), Firmicutes (28.9%), Proteobacteria (23.7%), Fusobacteria (10.5%) and Actinobacteria (5.1%). The predominant class were Bacteroidia (27.7%), Bacilli (16.9%), Gammaproteobacteria (12.3%), Fusobacteriia (10.5%) and Betaproteobacteria (9.4%). The predominant order were Bacteroidetes (27.7%), Lactobacillales (13.9%), Pasteurellales (13.6%), Fusobacteriales (10.5%) and Neisseriales (9.2%). The predominant family were Prevotellaceae (23.0%), Steptococcaceae (11.8%), Pasteurellaceae (11.4%), Neisseriaceae (9.2%) and Fusobacteriaceae (9.0%). The predominant genera were Prevotella (19.3%), Streptococcus (11.8%), Haemophilus (11.0%), Fusobacterium (9.0%) and Neisseria (8.9%). Significant differences were observed among the abundance of the genus Streptococcus, Aggregatibacter and Alloprevotella in saliva samples when compared among the OSCC, OLK and post groups (Table 2).
Gut microbiota in mucosa and feces of newly diagnosed, treatment-naïve adult inflammatory bowel disease and irritable bowel syndrome patients
Published in Gut Microbes, 2022
Hana Čipčić Paljetak, Anja Barešić, Marina Panek, Mihaela Perić, Mario Matijašić, Ivana Lojkić, Ana Barišić, Darija Vranešić Bender, Dina Ljubas Kelečić, Marko Brinar, Mirjana Kalauz, Marija Miličević, Dora Grgić, Nikša Turk, Irena Karas, Silvija Čuković-Čavka, Željko Krznarić, Donatella Verbanac
The abundance of individual taxa, presented in Table 2, revealed families and genera driving the difference between patient groups based on the effect size (>0.400). Compared to IBS, Dialister, Propionibacterium and Haemophilus were significantly enriched in IBD (p < .05), owing to an increase in UC patients. UC samples had a marked increase in Enterobacteriaceae, Neisseriaceae, S24-7, and decrease in Coriobacteriaceae (particularly in comparison to CD). Higher abundance of Lachnospiraceae and Erysipelotrichaceae was a marker of CD, reaching statistical significance when compared to the UC group. Compared to IBS, CD samples were significantly depleted in Alcaligenaceae, Desulfovibrionaceae, Phascolarctobacterium, and Oscillospira, with indicative reduction in Verrucomicrobiaceae and Adlercreutzia. Oscillospira, with indicative reduction in Verrucomicrobiaceae and Adlercreutzia.