Rapid detection of fosfomycin resistance in Escherichia coli and Klebsiella spp. strains isolated from urinary tract infections.

This study evaluates whether the rapid fosfomycin resistance (fosfomycin NP) method can be used for detecting fosfomycin resistance in routine laboratory work. Results from the disk diffusion and rapid fosfomycin NP methods were compared with the reference agar dilution method for Escherichia coli and Klebsiella spp. strains isolated from urinary tract infections. The study included 57 E. coli and 48 Klebsiella spp. isolates from urinary tract infections. The reference agar dilution and disk diffusion methods were performed in accordance with EUCAST recommendations, and the results were evaluated according to EUCAST V.10.0. The method developed by Nordmann et al. was used for rapid detection of fosfomycin resistance (Nordmann, P., Poirel, L., Mueller, L., 2019. Rapid Detection of Fosfomycin Resistance in Escherichia coli. J Clin Microbiol. 57(1), e01531-18. doi:https://doi.org/10.1128/JCM.01531-18). The acceptable categorical agreement (CA ≥ 90%) and the rates of major error (ME <3%) and very major error (VME < 3%) of the two methods were compared with the reference method according to the criteria of ISO 20776-1. Fosfomycin resistance was detected in 15.8% of E. coli and 75% of Klebsiella spp. isolates using the reference method. Disk diffusion method showed CA 89.5%, ME 12.5% in E. coli isolates, and CA 75%, ME 100% in Klebsiella spp. isolates. No VME was detected in both methods. The rapid fosfomycin NP method resulted in CA 96.4%, ME 0.0%, VME 22.2% in E. coli isolates, and CA 77.3%, ME 81.8%, and VME 3% in Klebsiella spp. isolates. We believe the results from both of disk diffusion assay and rapid fosfomycin NP for the E. coli and Klebsiella spp. isolates are incompatible with the reference method and should not be used as an alternative to the agar dilution method.

Comparison of arch width changes following orthodontic treatment with and without extraction using three-dimensional models.

OBJECTIVE: To compare the arch width changes in patients treated fixed orthodontic mechanics without extraction (Group 1), with upper and lower first premolar extractions (Group 2), and with upper first premolar extraction only (Group 3). MATERIALS AND METHODS: The study was conducted with pre- and post-treatment digital models from 240 patients. Anterior, middle, and posterior distances were measured on pre- and post-treatment models. At T1 measurements, the distance among the canine cusp tips, the second premolar buccal cusp tips, and the first molar mesiobuccal cusp tips were measured. In addition, the distance (D) between the intercanine and intermolar lines and the distance (D') between the interpremolar and intermolar lines were defined on the anatomic y-axis, and this distance was maintained in calculating posttreatment measurements (T2). Mandibular and maxillary arch width changes were evaluated within and between groups. RESULTS: Anterior, middle, and posterior arch widths increased significantly in Groups 1 and 3. Maxillary anterior and middle arch widths also increased in Group 2, but the increases were not statistically significant. Changes in maxillary anterior and middle arch widths were higher in Groups 1 and 3 when compared to Group 2. However, there was no statistically significant difference in mandibular arch changes between the groups. CONCLUSION: Extraction treatment mechanics did not cause narrow dental arches, but nonextraction treatment increased arch width in all 3 measurements. Treatments with only upper arch extraction showed similar results with nonextraction treatment.

Shear bond strength of orthodontic attachments bonded to impacted teeth under in vivo and in vitro conditions.

OBJECTIVES: To evaluate and compare the shear bond strength (SBS) of stainless steel and gold-plated attachments to impacted lower third molars in vivo and in vitro with a light-cured orthodontic resin. SETTING AND SAMPLE POPULATION: Sixteen patients with bilaterally full soft tissue impaction of lower third molars were recruited on a voluntary basis from an oral and maxillofacial surgery department. MATERIALS AND METHODS: A split-arch technique was used. Following surgical exposure of the crown, the tooth was luxated but not extracted. Then, two attachments (one stainless steel button and one gold-plated eyelet) were bonded to the labial enamel surface of the loosened tooth. Five minutes later, the luxated tooth was removed from its socket. In each patient, the impacted tooth on the other side was extracted, and attachments were bonded in vitro. The SBSs of the attachments were evaluated. For comparison, analysis of variance and multiple range tests were used (α = 0.05). RESULTS: Statistically significant differences were evident in attachment adhesion to the impacted tooth surfaces among the four groups (p < 0.001). Superior SBS values were obtained for stainless steel button groups bonded in vitro. The mean bond strengths of the groups bonded in vitro were better than those of the same groups bonded in vivo. CONCLUSIONS: Although the in vitro-bonded groups showed higher SBS values, adequate bond strength is possible with stainless steel buttons bonded in vivo.

Effects of sandblasting metal bracket base on the bond strength of a resin-modified glass ionomer cement: an in vitro study.

The introduction of air abrasion (sandblasting) technology to orthodontics may allow reaching optimum bond strength between the metal bracket and resin-modified glass ionomer cement. This study examined the effects of sandblasting metal bracket bases on the in vitro tensile bond strength of a resin-modified glass ionomer cement. Two-hundred foil-mesh based brackets were divided into ten groups and combinations of three sizes of aluminum oxide powder (25, 50 and 110 microm) and three sandblasting times (3, 6 and 9 seconds) were tested. One group was not sandblasted and used as control. Analysis of variance showed that bond strength was significantly affected by the sandblasting time (p < 0.001) and size of the aluminum oxide powder (p < 0.001). Only the group (SO(25)) sandblasted with 25 microm aluminum oxide powder for 3 seconds yielded higher mean bond strength than that of the control group. The bond strength values were also analyzed using a Weibull analysis, which showed the most favorable size (25 microm) and time combination (3 seconds), and the 5% and 90% probabilities of failures. This study suggests that sandblasting time and particle size have and important effect on the bond between the metal bracket and resin-modified glass ionomer cement.