Detection of resistance genes and susceptibility patterns in Bacteroides and Parabacteroides strains

Susceptibility to five antimicrobials was determined for Bacteroides spp. (n = 52) and Parabacteroides distasonis (n = 8). All isolates were susceptible to metronidazole. The resistance rates to ampicillin, cefoxitin, tetracycline and clindamycin were 98%, 9.6%, 65.3% and 19.2% of the Bacteroides strains, respectively. The genes cepA, cfiA, cfxA, tetQ, ermF and nim were found in 69.2%, 17.3% 9.6%, 50%, 7.7% and 3.8% for these strains respectively. All P. distasonis strains were resistant to ampicilin. Cefoxitin, tetracycline and clindamycin resistance rates were 75%, 87.5% and 50%, respectively. The ermF and nim genes were absent and 37.5%, 12.5%, 12.5% and 87.5% of this strains possessed cepA, cfiA, cfxA and tetQ genes, respectively. Ten cfiA gene positive strains of Bacteroides and Parabacteroides were submitted to E-test with imipenem and amoxicillin–clavulanate. The resistance rate to imipenem was 4.1% and 8.3% to amoxicillin–clavulanate. This feature is for the first time described in Brazil.     

O-Glycosylation in Cell Wall Proteins in Scedosporium prolificans Is Critical for Phagocytosis and Inflammatory Cytokines Production by Macrophages

In this study, we analyze the importance of O-linked oligosaccharides present in peptidorhamnomannan (PRM) from the cell wall of the fungus Scedosporium prolificans for recognition and phagocytosis of conidia by macrophages. Adding PRM led to a dose-dependent inhibition of conidia phagocytosis, whereas de-O-glycosylated PRM did not show any effect. PRM induced the release of macrophage-derived antimicrobial compounds. However, O-linked oligosaccharides do not appear to be required for such induction. The effect of PRM on conidia-induced macrophage killing was examined using latex beads coated with PRM or de-O-glycosylated PRM. A decrease in macrophage viability similar to that caused by conidia was detected. However, macrophage killing was unaffected when beads coated with de-O-glycosylated PRM were used, indicating the toxic effect of O-linked oligosaccharides on macrophages. In addition, PRM triggered TNF-α release by macrophages. Chemical removal of O-linked oligosaccharides from PRM abolished cytokine induction, suggesting that the O-linked oligosaccharidic chains are important moieties involved in inflammatory responses through the induction of TNF-α secretion. In summary, we show that O-glycosylation plays a role in the recognition and uptake of S. prolificans by macrophages, killing of macrophages and production of pro- inflammatory cytokines.     

Pectate Lyase Pollen Allergens: Sensitization Profiles and Cross-Reactivity Pattern

BackgroundPollen released by allergenic members of the botanically unrelated families of Asteraceae and Cupressaceae represent potent elicitors of respiratory allergies in regions where these plants are present. As main allergen sources the Asteraceae species ragweed and mugwort, as well as the Cupressaceae species, cypress, mountain cedar, and Japanese cedar have been identified. The major allergens of all species belong to the pectate lyase enzyme family. Thus, we thought to investigate cross-reactivity pattern as well as sensitization capacities of pectate lyase pollen allergens in cohorts from distinct geographic regions.MethodsThe clinically relevant pectate lyase pollen allergens Amb a 1, Art v 6, Cup a 1, Jun a 1, and Cry j 1 were purified from aqueous pollen extracts, and patients´ sensitization pattern of cohorts from Austria, Canada, Italy, and Japan were determined by IgE ELISA and cross-inhibition experiments. Moreover, we performed microarray experiments and established a mouse model of sensitization.ResultsIn ELISA and ELISA inhibition experiments specific sensitization pattern were discovered for each geographic region, which reflected the natural allergen exposure of the patients. We found significant cross-reactivity within Asteraceae and Cupressaceae pectate lyase pollen allergens, which was however limited between the orders. Animal experiments showed that immunization with Asteraceae allergens mainly induced antibodies reactive within the order, the same was observed for the Cupressaceae allergens. Cross-reactivity between orders was minimal. Moreover, Amb a 1, Art v 6, and Cry j 1 showed in general higher immunogenicity.ConclusionWe could cluster pectate lyase allergens in four categories, Amb a 1, Art v 6, Cup a 1/Jun a 1, and Cry j 1, respectively, at which each category has the potential to sensitize predisposed individuals. The sensitization pattern of different cohorts correlated with pollen exposure, which should be considered for future allergy diagnosis and therapy.     

Cytotoxicity and enzymatic activity inhibition in cell lines treated with novel iminosugar derivatives

Iminosugars are monosaccharide analogues that have been demonstrated to be specific inhibitors for glycosidases and are currently used therapeutically in several human disorders. N-alkylated derivatives of d-fagomine and (2R,3S,4R,5S)-2-(hydroxymethyl)-5-methylpyrrolidine-3,4-diol with aliphatic chains were tested in eight human cancer cell lines to analyze their cytotoxicity and the inhibitory effect in the activities of specific glycosidases. Results indicate that these compounds were more cytotoxic as the length of the alkyl chain increases. N-dodecyl-d-fagomine inhibited specifically the α-d-glucosidase activity in cell lysates, whereas no effect was detected in other glycosidases. The N-dodecyl derivative of (2R,3S,4R,5S)-2-(Hydroxymethyl)-5-methylpyrrolidine-3,4-diol induced specific inhibition against α-l-fucosidase in cell lysates. Our results indicated that the length of the alkyl chain linked to the iminosugars determine their cytotoxicity as well as the inhibitory effect on the enzymatic activities of specific glycosidases, in human cancer cell lines.     

Total low-molecular-weight antioxidants as a summary parameter, quantified in biological samples by a chemiluminescence inhibition assay

Aerobic metabolism requires a complex antioxidative system to balance reactive oxygen species (ROS). When in excess, ROS disrupt cellular activities and molecular structures. Owing to the variety of ROS, there are different antioxidative activities that require various tests for their detection. The so-called 'total antioxidative capacity' inhibition assay presented in this paper can be used to quantify the overall activity of low-molecular-weight antioxidants (AOs) in biological samples. The assay is based on enhanced horseradish peroxidase-catalyzed luminol chemiluminescence. It can be fine-tuned so that the biological samples meet the requirements of the light detector. A detailed protocol describing all relevant parameters is provided. The procedure is quick, inexpensive and reproducible. The assay can be used with diverse biological materials such as plant extracts and blood plasma. Hence, it is applicable to fields as diverse as crop breeding, medical diagnostics or food sciences. The time needed for the assay depends on the number of samples and their AO content. The protocol takes one working day to complete when five samples with five replicates are measured sequentially.     

Oral manifestations in chikungunya patients: A systematic review

BackgroundChikungunya fever is considered an abrupt onset arbovirus transmitted by mosquitoes, mainly Aedes aegypti and Aedes albopictus. The disease has a significant impact on the quality of life of affected persons, and many of its numerous symptoms have not yet been properly clarified, such as the manifestations that can occur in the oral cavity. The aim of this study was to identify the main oral manifestations related to chikungunya fever, as well as describe the demographic characteristics of patients, by conducting a systematic review of the literature.Methods and findingsSearches were performed in MEDLINE (PubMed), Embase (Elsevier), LILACS (VHL), Cochrane Library, Scopus, and CAPES electronic databases for theses and dissertations published up to January 16, 2021 without language and date restrictions. Additional manual searches of gray literature, reference list, and Google Scholar were carried out. We included 27 studies highlighting mainly oral manifestations that cause masticatory discomfort such as ulcers and oral thrush, gingival bleeding, pain and burning of the oral mucous membranes, temporomandibular joint (TMJ) arthralgia, opportunistic infections, and changes in taste.ConclusionsThere seems to be a predominance of oral manifestations that cause discomfort when chewing, such as ulcerations in the acute phase of the disease, with complete remission within 3 to 10 days after the onset, apparently mostly affecting women and older persons. These oral manifestations can be compatible with basic viral infections related to inflammatory response and transitory immunosuppression.