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Bolt-grouting support is a commonly used method for stabilizing surrounding rock in underground engineering. Its effectiveness directly influences the safety and stability of deep underground engineering. Field monitoring showed that the maximum deformation of the pump chamber reached 751.0 mm. The maximum depth of the severely damaged zone was 7.0 m. It is planned to implement bolt-grouting support in the pump chamber to control surrounding rock deformation. In order to clarify the strength variation law of the grouting diffusion zone and guide the bolt-grouting scheme, grouting diffusion tests were conducted. Tests revealed that the compressive strength of the grouted specimens decreased with increasing diffusion distance. According to the compressive strength within different diffusion ranges, it can be classified into initial decline zone, gradual decline zone, and edge zone. Based on the established strength variation indicators, it is found that the aggregate size has a greater influence on the grouting diffusion range than the water-cement ratio. In tests A 1 to A 3 , the grouting diffusion range was increased from 800 mm to 1000 mm. The grouting diffusion range of tests B 1 , B 2 and B 3 was all 1000 mm. Based on the research of this paper, relevant suggestions for bolt-grouting support are put forward. After the implementation of bolt-grouting support in the pump chamber, the maximum surrounding rock deformation was 39.5 mm, indicating effective control of the deformation.

Objectives Recent research has demonstrated that platelet-rich fibrin (PRF) is an appropriate carrier for ampicillin/sulbactam. The aim of the study was to investigate whether PRF is also a suitable bio-carrier for clindamycin (CLI). Methods PRF membranes were produced from 36 patients receiving intravenous therapy with CLI (e.g. due to the diagnosis of an osteonecrosis of the jaw or infections). Concentrations of CLI in PRF membranes were measured with liquid chromatography-tandem mass spectrometry, and the antimicrobial effects were investigated in vitro in agar diffusion tests with fresh PRF and PRF stored for 24 h. Storage was performed in an incubator at 36 °C to simulate the in-vivo situation. Results The mean concentration of CLI in plasma was 1.0 ± 0.3 μg/100 mg plasma; in resulting PRF membranes 0.7 ± 0.4 μg/100 mg PRF. Agar diffusion tests were performed with Staphylococcus aureus , Streptococcus pneumoniae , Streptococcus mitis , Porphyromonas gingivalis,  and Fusobacterium nucleatum . Mean inhibition zones, in mm, for fresh PRF were 17.3, 12.2, 18.8, 17.1, 25.8 and 18.1, 12.7, 19.2, 17.3, and 26.3 for stored PRF, respectively. Conclusion The results demonstrate that PRF is a suitable bio-carrier for CLI when administered systemically to patients. The concentration in PRF generated from patients after infusion of 600 mg CLI dose suffices to target clinically relevant bacteria. Clinical relevance Using PRF as a carrier for local antibiotic application can prevent infections in oral and maxillofacial surgery. Within the study limitations, the findings could expand the scope of PRF application by adding CLI as a new antibiotic to the spectrum of PRF therapy.

ObjectivesMechanisms of wound healing are often impaired in patients with osteonecrosis of the jaw (ONJ). According to the guidelines for the treatment of this disease, early surgical intervention is indicated. However, surgery often faces complications such as wound healing disorders. The application of platelet-rich fibrin (PRF) after necrosectomy between bone and mucosa may constitute a promising approach to improve surgical results. An aspect that was not investigated until now is that PRF acts as a “bio-carrier” for antibiotics previously applied intravenously.Materials and methodsWe investigated the antimicrobial properties of PRF in 24 patients presenting ONJ undergoing systemic antibiosis with ampicillin/sulbactam. We measured the concentration of ampicillin/sulbactam in plasma and PRF and performed agar diffusion tests. Ampicillin/sulbactam was applied intravenously to the patient 10 minutes for blood sampling for PRF. No further incorporation of patients’ blood or PRF product with antibiotic drugs was obtained. Four healthy patients served as controls.ResultsOur results revealed that PRF is highly enriched with ampicillin/sulbactam that is released to the environment. The antibiotic concentration in PRF was comparable to the plasma concentration of ampicillin/sulbactam. The inhibition zone (IZ) of PRF was comparable to the standard ampicillin/sulbactam discs used in sensitivity testing.ConclusionsThe results of our study demonstrated that PRF is a reliable bio-carrier for systemic applied antibiotics and exhibits a large antimicrobial effect.Clinical relevanceWe describe a clinically useful feature of PRF as a bio-carrier for antibiotics. Especially when applied to poorly perfused tissues and bone such as in ONJ, the local release of antibiotics can reduce wound healing disorders like infections.

ObjectivesDifferent platelet-rich fibrin (PRF) protocols exist and are known to differ in resulting mechanical and bioactive properties. Centrifugation parameters may also influence drug release, in particular antibiotics, when using PRF as a bio-carrier. We thus evaluated three common protocols regarding effects on the bio-carrier properties.Materials and methodsIn a prospective trial comprising 33 patients, we compared different protocols for PRF as a bio-carrier for ampicillin/sulbactam (SAM). Blood samples were taken shortly after a single dose of ampicillin/sulbactam (2 g/1 g) was administered to patients intravenously. PRF was obtained by centrifugation and three protocols were used: protocol A (1300 rpm, 8 min, RCF-max = 208 g), B (2300 rpm, 12 min, RCF-max = 652 g), and C (1500 rpm, 14 min, RCF-max = 276 g). The antibacterial activity of PRF was investigated against five oral species in vitro, based on agar diffusion methodology.ResultsThe study demonstrates that a single dose of SAM is sufficient to reach high concentrations in PRF in all protocols (150 µg/ml), which is comparable to the plasma SAM concentration. Antibacterial activity was inferred from the diameter of inhibition zones seen in agar diffusion tests using PRF discs. Protocol B resulted in the largest inhibition zones. One-way ANOVA revealed statistically improved results for protocol B for some bacteria.ConclusionsThe study provides valuable data on PRF antibiotic enrichment, notably SAM. A single dose of SAM is sufficient to reach clinically relevant concentrations in PRF.Clinical relevanceThese findings potentially extend the application of PRF, for example in patients with osteonecrosis of the jaw or in oral surgery (e.g., stick bone).

Injectable ceftriaxone and oral cefixime are the last agents effective against . In vitro antimicrobial-susceptibility testing (AST) is done to identify the most efficacious antibiotic needed to combat the infection in that particular individual. The objective of this study was to evaluate whether Kirby-Bauer (KB) disk-diffusion tests can detect isolates that have decreased susceptibility to ceftriaxone and cefixime for appropriate clinical management. A total of 1,633 consecutive clinical isolates of were collected from January 1, 2013 to December 31, 2017 from seven dermatology clinics located in five provinces in China. Consistency between KB disk-diffusion tests and the agar-dilution method, as well as sensitivity of the KB test for detecting isolates with decreased susceptibility to ceftriaxone and cefixime, were determined using 1,306 clinical isolates that had been recovered to complete agar-dilution AST. The prevalence of isolates with decreased susceptibility to ceftriaxone and cefixime was 12.1% (198 of 1,633) and 12.7% (208 of 1,633), respectively, using KB disk-diffusion tests. The prevalence of isolates with decreased susceptibility was 9.9% (129 of 1,306) for ceftriaxone and 9.9% (129 of 1,305) for cefixime using agar-dilution AST. The categorical agreement of these two methods was 80.9% for both ceftriaxone and cefixime. Compared to agar-dilution AST, the sensitivity of the KB test for detecting isolates with decreased susceptibility was 22.5% (29 of 129) for ceftriaxone and 29.5% (38 of 129) for cefixime, and its specificity 87.3% (1,028 of 1,177) for ceftriaxone and 86.7% (1,018 of 1,176) for cefixime. Although KB tests are easy to carry out in clinical practice, their ability to detect cephalosporin-resistant gonorrhoea strains is limited. This method is not an appropriate selection for screening cephalosporin-resistant gonorrhoea strains in clinical practice in China.

Carbapenemase-producing Enterobacterales (CPE) are considered among the highest threats to global health by WHO. Their detection is difficult and time-consuming. We developed a random-forest machine learning (ML) model, CarbaDetector, to predict carbapenemase production from inhibition zone diameters of eight antibiotics, using 385 isolates for training with whole genome sequencing as reference. Validation on two external datasets (A = 282, B = 518 isolates) shows high performance: sensitivity/specificity are 96.6%/84.4% (training), 96.3%/86.1% (A), and 91.2%/87.0% (B, five antibiotics). In contrast, the algorithms of EUCAST and the Antibiogram Committee of the French Society of Microbiology (CA-SFM) exhibit lower specificity (8.2% and 40.1%, respectively on the training dataset). In this work, we show that CarbaDetector, available as a web-app, reduces unnecessary confirmatory testing and accelerates the time to result. This approach offers high sensitivity and improved specificity compared to standard algorithms and has the potential to improve CPE detection, especially in resource-limited settings. Carbapenems are last-resort antibiotics, but resistance is rising due to hydrolyzing enzymes called carbapenemases. The authors present a machine learning algorithm and web-app to rapidly predict carbapenemase-production in Enterobacterales .

Background: Coffee is a major dietary source of polyphenols. Previous research found that coffee had a protective effect on periodontal disease. In this study, we aimed to investigate whether coffee extract and its primary phenolic acid, chlorogenic acid, affect the growth and protease activity of a periodontopathogen Porphyromonas gingivalis (P. gingivalis). Methods: Coffee extract and chlorogenic acid were prepared by a two-fold serial dilution. The turbid metric test and plate count method were used to examine the inhibitory effects of chlorogenic acid on P. gingivalis. The time-kill assay was used to measure changes in the viability of P. gingivalis after exposure to chlorogenic acid for 0–24 h. The protease activity of P. gingivalis was analyzed using the optical density of a chromogenic substrate. Results: As a result, the minimum inhibitory concentration (MIC) of chlorogenic acid was 4 mg/mL, and the minimum bactericidal concentration was 16 mg/mL. Chlorogenic acid at concentrations above MIC resulted in a longer-lasting inhibitory effect on P. gingivalis viability and significantly reduced associated protease activity. The coffee extract showed antibacterial activity as observed by the disk diffusion test, whereas these inhibitory effects were not affected by different roast degrees of coffee. Conclusions: Collectively, our novel findings indicate that chlorogenic acid not only has antimicrobial activity but also reduced the protease activity of P. gingivalis. In addition, coffee extract inhibits the proliferation of P. gingivalis, which may partly be attributed to the effect of chlorogenic acid.

Aim: The purpose of this study was to evaluate the efficacy of 3% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), and chitosan nanoparticles against Candida albicans using the agar disc-diffusion test. Materials and Methods: Strain of C. albicans was cultivated in Sabouraud Dextrose Agar. Chitosan nanoparticles were synthesized using an ionic gelation method. Four groups were made according to the irrigants used. Group 1: 3% NaOCl, Group 2: 2% CHX, Group 3: chitosan nanoparticles, and Group 4: saline as control. Discs were added with the different irrigants and placed in a dish containing C. albicans. The plates were incubated at 37°C for 24h. The zone of inhibition was measured in millimeter. Results: Statistical analysis was performed using the test of one-way variance (ANOVA) and post hoc Tukey. Group 1 showed significantly higher zone of inhibition compared to Groups 2 and 3 (P < 0.05). There were no significant differences between the zones of inhibition of Groups 2 and 3 (P < 0.05). Conclusion: Chitosan nanoparticles and 2% CHX have similar efficacy against C. albicans, whereas 3% NaOCl was significantly better than both chitosan nanoparticles and CHX.

Antimicrobial susceptibility testing (AST) is essential for determining the in vitro activity of antimicrobial agents against specific microorganisms. Reliable data from AST is needed for the detection of resistance mechanisms which are crucial to ensure appropriate treatment of patients in healthcare settings or in the community. Automated AST readers of the inhibition zone provide valuable tools for standardizing the testing process in microbiology laboratories, enabling faster and more reliable interpretation of results. The aim of this study was to evaluate AntibiHórus, an in-house developed automated disc diffusion AST reader, by comparing its performance against manual reading of the inhibition zones using a ruler. A total of 500 ASTs, including both Gram-negative and Gram-positive bacteria, were evaluated using 22 different antimicrobial discs, resulting in 4,709 inhibition zone measurements. Manual readings with a ruler were compared with the automated readings from AntibiHórus. The overall categorical agreement (CA) between AntibiHórus and manual reading was 96.86%, with minimal error rates, 2.08% for Very Major Errors (VME), 0.30% for Major Errors (ME), and 0.76% for Minor Errors (MiE). Statistical analysis showed a strong correlation between methods (Pearson correlation coefficient R ≥ .95). The findings demonstrate that AntibiHórus is a reliable tool for routine microbiology laboratory work, enhancing the efficiency, standardization, and accuracy of AST analysis by automating inhibition zone measurement and interpretation.

In a study of 39 isolates of Edwardsiella piscicida made from Korean aquaculture sites, sul genes were detected in 16 isolates and dfr genes in 19. Ten isolates were shown to contain both sul and dfr genes. MIC and disc diffusion zones assays were performed to measure the phenotypic susceptibilities of the 39 isolates. Normalized resistance interpretation was applied to these data to categorize isolates as either fully susceptible or as manifesting reduced susceptibility. The standard CLSI protocols specify the use of a mixture of sulfamethoxazole/trimethoprim (20:1) in both MIC and disc diffusion tests. Using the CLSI MIC protocol, 100% of the isolates containing dfr genes, but only 75% of the isolates containing sul genes, were categorized as manifesting reduced susceptibility. Using the CLSI disc diffusion protocol, only 58% of the isolates containing dfr genes and 69% of those containing sul genes were categorized as manifesting reduced susceptibility. When the single agent trimethoprim was substituted for the combined mixture in both the MIC and disc diffusion protocols, 100% of the dfr- positive isolates were categorized as NWT. When the single-agent sulfamethoxazole was substituted, the analysis of the MIC characterized 100% and the disc zone data 94% of the sul -positive isolates as manifesting reduced susceptibility. It is argued that the use of trimethoprim and sulfamethoxazole as single agents in phenotypic susceptibility tests would provide more meaningful data than the currently recommended use of these two agents combined.