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Background: Pediatric dental crowns play an integral role as they maintain the form and function and prolong the life of the affected tooth. However, placing a crown in the oral cavity creates a new niche for the adhesion of microorganisms that can lead to plaque accumulation, gingival inflammation, and the development of secondary caries, which in the long term might determine the clinical success of the restored tooth. The present study allowed us to assess the changes caused by the full coverage restorations at a clinical, immunological, and microbiological level using enzyme-linked immunosorbent assay (ELISA) and microbial analysis. Materials and methods: The in vivo analysis consisted of a total of 26 children aged 3-10 years. They were divided into two groups, group I (n = 13) children receiving preformed zirconia crowns and group II receiving stainless steel crowns (SSCs). Plaque index (PI) scores, gingival index (GI) scores, and interleukin-6 (IL-6) levels were assessed at baseline and at 45 days of follow-up. The in vitro part of the study consisted of 13 preformed zirconia crowns and 13 SSCs which were immersed in artificial saliva containing strains of Lactobacillus casei which were then processed for their microbial analysis. Results: On mean comparison, preformed zirconia crowns performed superiorly both clinically and immunologically compared to SSCs. Microbial analysis using independent t-test revealed that the colony-forming units (CFU) per milliliter was statistically significantly higher for the SSCs, and the mean difference among the groups was statistically significant (p < 0.01). Conclusion: Preformed zirconia crowns can be a relative replacement for SSCs in primary teeth with the advantage of esthetics and superior periodontal health. How to cite this article: Saharia NP, Malik M, Jhingan P, et al. Assessment of Interleukin-6 Levels and Lactobacillus casei Counts in Pediatric Stainless Steel and Zirconia Crowns: A Comparative Study. Int J Clin Pediatr Dent 2024;17(4):395-403.

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The ability of Candida albicans to switch its morphology from yeast to filaments, known as polymorphism, may bias the methods used in microbial quantification. Here, we compared the quantification methods [cell/mL, colony forming units (CFU)/mL, and the number of nuclei estimated by viability polymerase chain reaction (vPCR)] of three strains of C. albicans (one reference strain and two clinical isolates) grown as yeast, filaments, and biofilms. Metabolic activity (XTT assay) was also used for biofilms. Comparisons between the methods were evaluated by agreement analyses [Intraclass and Concordance Correlation Coefficients (ICC and CCC, respectively) and Bland-Altman Plot] and Pearson Correlation (α = 0.05). Principal Component Analysis (PCA) was employed to visualize the similarities and differences between the methods. Results demonstrated a lack of agreement between all methods irrespective of fungal morphology/growth, even when a strong correlation was observed. Bland-Altman plot also demonstrated proportional bias between all methods for all morphologies/growth, except between CFU/mL X vPCR for yeasts and biofilms. For all morphologies, the correlation between the methods were strong, but without linear relationship between them, except for yeast where vPCR showed weak correlation with cells/mL and CFU/mL. XTT moderately correlated with CFU/mL and vPCR and weakly correlated with cells/mL. For all morphologies/growth, PCA showed that CFU/mL was similar to cells/mL and vPCR was distinct from them, but for biofilms vPCR became more similar to CFU/mL and cells/mL while XTT was the most distinct method. As conclusions, our investigation demonstrated that CFU/mL underestimated cells/mL, while vPCR overestimated both cells/mL and CFU/mL, and that the methods had poor agreement and lack of linear relationship, irrespective of C. albicans morphology/growth.1.

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Measuring the abundance of microbes in a sample is a common procedure with a long history, but best practices are not well-conserved across microbiological fields. Serial dilution methods are commonly used to dilute bacterial cultures to produce countable numbers of colonies, and from these counts, to infer bacterial concentrations measured in colony-forming units (CFUs). The most common methods to generate data for CFU point estimates involve plating bacteria on (or in) a solid growth medium and counting their resulting colonies or counting the number of tubes at a given dilution that have growth. Traditionally, these types of data have been analyzed separately using different analytic methods. Here, we build a direct correspondence between these approaches, which allows one to extend the use of the most probable number method from the liquid tubes experiments, for which it was developed, to the growth plates by viewing colony-sized patches of a plate as equivalent to individual tubes. We also discuss how to combine measurements taken at different dilutions, and we review several ways of analyzing colony counts, including the Poisson and truncated Poisson methods. We test all point estimate methods computationally using simulated data. For all methods, we discuss their relevant error bounds, assumptions, strengths, and weaknesses. We provide an online calculator for these estimators.Estimation of the number of microbes in a sample is an important problem with a long history. Yet common practices, such as combining results from different measurements, remain sub-optimal. We provide a comparison of methods for estimating abundance of microbes and detail a mapping between different methods, which allows to extend their range of applicability. This mapping enables higher precision estimates of colony-forming units (CFUs) using the same data already collected for traditional CFU estimation methods. Furthermore, we provide recommendations for how to combine measurements of colony counts taken across dilutions, correcting several misconceptions in the literature.

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Straw biochar is a commonly recognized agricultural amendment that can improve soil quality and reduce carbon emissions while sequestering soil carbon. However, the mechanisms underlying biochar's effects on annual soil carbon emissions in seasonally frozen soil areas and intrinsic drivers have not been clarified. Here, a 2-y field experiment was conducted to investigate the effects of different biochar dosages (0, 15, and 30, t ha-1; B0 (CK), B15, and B30, respectively) on carbon emissions (CO2 and CH4) microbial colony count, and soil-environment factors. The study period was the full annual cycle, including the freeze-thaw period (FTP) and the crop growth period (CP). Structural equation modeling (SEM) was developed to reveal the key drivers and potential mechanisms of biochar on carbon emissions. Biochar application reduced soil carbon emissions, with the reduction rate positively related to the biochar application rate (B30 best). During FTP, the reduction rate was 11.5% for CO2 and 48.2% for CH4. During CP, the reduction rate was 17.9% for CO2 and 34.5% for CH4. Overall, compared with CK, B30 treatment had a significant effect on reducing total soil carbon emissions (P < 0.05), with an average decrease of 16.7% during the two-year test period. The study also showed that for soils with continuous annual cycles (FTP and CP), carbon emissions were best observed from 10:00-13:00. After two years of freeze-thaw cycling, biochar continued to improve soil physical and chemical properties, thereby increasing soil microbial colony count. Compared with B0, the B30 treatment significantly increased the total colony count by 74.3% and 263.8% during FTP and CP (P < 0.05). Structural equation modeling (SEM) indicated that, with or without biochar application, the soil physicochemical properties directly or indirectly affected soil CO2 and CH4 emission fluxes through microbial colony count. The total effects of biochar application on CO2 emission fluxes were 0.50 (P < 0.05) and 0.64 (P < 0.01), respectively, but there was no significant effect on CH4 emission fluxes (P > 0.05). Among them, soil water content (SWC), soil temperature (ST) and soil organic carbon (SOC) were the main environmental determinants of CO2 emission fluxes during the FTP and CP. The total effects were 0.57, 0.65, and 0.53, respectively. For CH4, SWC, soil salinity (SS) and actinomycete colony count were the main environmental factors affecting its emission. The total effects were 0.50, 0.45, 0.44, respectively. For freeze-thaw alternating soils, the application of biochar is a feasible option for addressing climate change through soil carbon sequestration and greenhouse gas emissions mitigation. Soil water-heat-salt-fertilization and microbial communities are important for soil carbon emissions as the reaction matrix and main participants of soil carbon and nitrogen biochemical transformation.

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Saccharomycopsis fibuligera, which produces enzymes like amylase and protease as well as flavor substances like ß-phenyl ethanol and phenyl acetate, plays a crucial role in traditional fermented foods. However, this strain still lacks a high-density fermentation culture, which has had an impact on the strain's industrial application process. Therefore, this study investigated the optimization of medium ingredients and fermentation conditions for high-density fermentation of S. fibuligera Y1402 through single-factor design, Plackett-Burman design, steepest ascent test, and response surface analysis. The study found that glucose at 360.61 g/L, peptone at 50 g/L, yeast extract at 14.65 g/L, KH2PO4 at 5.49 g/L, MgSO4 at 0.40 g/L, and CuSO4 at 0.01 g/L were the best medium ingredients for S. fibuligera Y1402. Under these conditions, after three days of fermentation, the total colony count reached 1.79 × 108 CFU/mL. The optimal fermentation conditions were determined to be an initial pH of 6.0, an inoculum size of 1.10%, a liquid volume of 12.5 mL/250 mL, a rotation speed of 120 r/min, a fermentation temperature of 21 °C and a fermentation time of 53.50 h. When fermentation was conducted using the optimized medium and conditions, the total colony count achieved a remarkable value of 5.50 × 109 CFU/mL, exhibiting a substantial increase of nearly 31 times the original value in the optimal culture medium. This significant advancement offers valuable insights and a reference for the industrial-scale production of S. fibuligera.

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Poultry is a common reservoir for Campylobacter and a main source for human campylobacteriosis. With broiler being the predominant poultry for food production, most food safety related research is conducted for this species, for turkey, few studies are available. Although animals are typically colonized at the farm level, the slaughtering process is considered an important factor in re- and cross-contamination. We examined the development of Campylobacter, E. coli and total colony counts (TCC) after several processing steps in three broiler and one turkey slaughterhouses. Whole carcass rinsing and neck skin sampling was applied for broilers resulting in 486 samples in total, while 126 neck skin samples were collected for turkeys. A decrease in the loads of the different bacterial groups along the broiler slaughtering process was observed. Campylobacter mean counts dropped from 4.5 ± 1.7 log10 CFU/ml after killing to 1.6 ± 0.4 log10 CFU/ml after chilling. However, an increase in Campylobacter counts was evident after evisceration before the values again decreased by the final processing step. Although the Campylobacter prevalence in the turkey samples showed a similar development, the bacterial loads were much lower with 1.7 ± 0.3 log10 CFU/g after killing and 1.7 ± 0.4 log10 CFU/g after chilling compared to those of broilers. The loads of E. coli and total colony count of turkey were higher after killing, were reduced by scalding and remained stable until after chilling. This study highlights trends during the slaughtering process in reducing the levels of Campylobacter, E. coli, and total colony counts for broiler and turkey carcasses, from the initial step to after chilling. These results contribute to our understanding of microbial dynamics during meat processing.

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Objective:To investigate the application value of ultrasound-guided multimodal examinations in the diagnosis of lymph node mycobacterial infection.Methods:The clinical data of 42 patients with suspected lymph node mycobacterial infection who were initially diagnosed at the Affiliated Hospital of Shaoxing University from January 2019 to December 2020 were retrospectively analyzed. All patients underwent an ultrasound-guided lymph node-negative pressure puncture. Acid-fast staining, bacterial culture, pathological examination or their combination were used to screen lymph nodes for mycobacterial infection. The results were compared with those of acid-fast staining and bacterial culture of sputum and bronchoalveolar lavage fluid smears.Results:The combined application of acid fast staining, bacterial culture, and pathological examination for the puncture fluid smear showed a positive rate of 71.4% (30/42), which was significantly higher than the positive rate [26.2% (11/42)] for acid fast staining of the puncture fluid smear, the positive rate [42.9% (18/42)] for bacterial culture of the puncture fluid, and the positive rate [50.0% (21/42)] of pathological examination ( χ2 = 17.20, 7.00, 4.04, P < 0.001, P < 0.01, P = 0.040). The positive rate for sputum smear and bacterial culture was 21.4% (9/33). The positive rate for acid fast staining and bacterial culture of the bronchoalveolar lavage fluid was 28.6% (12/30). The differences were statistically significant ( χ2 = 21.11, 15.43, both P < 0.001). Conclusion:Ultrasound-guided negative pressure aspiration and puncture biopsy of lymph nodes combined with acid fast staining, bacterial culture, and pathological examinations can markedly increase the detection rate and diagnostic rate of mycobacterial infection.

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Background: Chronic periodontitis is the most common dental disease reported globally as well as in India. Periodontal pathogens are usually seen in samples of gingival tissues, crevicular blood, GCF (gingival crevicular fluid), and dental plaque. Apart from the conventional mechanical treatment, laser disinfection is a recent advancement that change shows greater efficacy in reducing the disease progression and changing the bacterial flora. Aim: The present study aimed to assess the Immediate response of diode laser on the microbial load in subjects with chronic Periodontitis as assessed in saliva, crevicular blood, and GCF (gingival crevicular fluid) samples. Materials and Methods: The study recruited 90 subjects with chronic periodontitis. For split-mouth fashion, the mouth, of each participant was divided into two halves and was divided into two groups randomly. Group I (test group) subjects underwent laser disinfection (970 ± 15 nm). Group II subjects served as controls and underwent saline irrigation. For all participants, crevicular blood, saliva, and GCF samples were collected before and immediately following disinfection for microbial analysis. Results: Microbial load reduction was seen in both groups following treatment. However, a significantly higher reduction was seen in the test group with laser disinfection. Compared to the crevicular blood sample, a greater reduction was seen in saliva and GCF samples. Conclusion: The present study concludes that Diode Laser (970 ± 15 nm) application shows an immediate reduction of the bacterial load in subjects with chronic periodontitis.

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The high incidence of demineralization around orthodontic brackets has led to the development of preventive measures. Incorporation of antibacterial or remineralizing agents into orthodontic adhesives is an attractive method. This single-center, split-mouth, randomized controlled clinical trial was conducted to assess the effect of a modified composite containing TiO2 nanoparticles on the Streptococcus mutans population and to prevent demineralization around orthodontic brackets. Each participant was assigned a random sequence (AB or BA). During the bonding session, the control lateral incisor was bonded with a conventional composite and the contralateral incisor was bonded with a composite containing nano TiO2 particles (1%weight). The eligibility criteria included the presence of S. mutans in the dental plaque and absence of active caries, fractures or cracks. The S. mutans count in the dental plaque immediately around the brackets was evaluated at baseline and 1, 3, and 6 months after bonding. The specificity of the colonies was determined by PCR. The DIAGNOdent score was assessed at baseline and re-assessed every month up to the sixth month. Salivary samples were collected at T0, T1, and T3 to assess the amount of Ti released from the composite. The cytotoxicity of the modified composites was evaluated using an MTT assay. Participants, examiners, and data analyzers were blinded to the test and intervention groups. Forty-two patients ranging from 12 to 25 years were enrolled in this study. The amount of Ti released into saliva was insignificant and far below the toxic level. There was no significant difference between the S. mutans counts of the studied tooth S. mutans counts at any time point evaluated. DIAGNOdent scores on both sides increased significantly after the first month. However, this increase was higher on the test side (p < 0.001), and a significant difference of 2.6 scores remained throughout the study period. No severe adverse events were observed. Orthodontic composites containing TiO2 nanoparticles may prevent demineralization induced around brackets during orthodontic treatment. However, the antibacterial effects were not statistically significant.Registration: The protocol was registered with the IRCT.ir (IRCT20140215016582N6).

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AIM: Determine the utility of the Periodic Environmental Biosecurity Assessment Program (PEBAP) in achieving clean air as measured by the number of colony-forming units (CFU) of fungi and bacteria in the air. BACKGROUND: There is no international consensus on the sampling frequency, the recommended limits for microorganisms in the air nor on the usefulness of routine microbiological air monitoring of hospitals. METHODS: During the PEBAP, data were recollected between 2010 and 2017 in eight hospitals in southeast Spain. Air samples were collected in very high risk rooms (VHRRs) and high risk rooms (HRRs), unoccupied, using active sampling methods. Temperature, relative humidity, air changes per hour (ACH), and differential pressure were measured. When limits of CFU of opportunistic fungi and bacteria established in the PEBAP were exceeded, corrective measures were adopted. RESULTS: We found a reduction (p < .01) of percentage of air samples with fungi growth throughout the years of PEBAP in all rooms. Aspergillus was the most frequent opportunistic fungus. We found a high compliance of the standards of CFU of bacteria in HRR, and the percentage of compliance in VHRR was lower than in HRR in all years. Differences in environmental and design parameters were statistically significant (p < .05) between rooms, except for ACH. CONCLUSIONS: PEBAP resulted in a useful tool to maintain and improve air quality in hospitals. The control of environmental biosecurity requires a multidisciplinary approach from preventive medicine, engineering, and cleaning services. Aspergillus is the most frequent opportunistic fungus in southeast Spain.

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Mouse α-defensins, better known as cryptdins, are host protective antimicrobial peptides produced in the intestinal crypt by Paneth cells. To date, more than 20 cryptdin mRNAs have been identified from mouse small intestine, of which the first six cryptdins (Crp1 to Crp6) have been isolated and characterized at the peptide level. We quantified bactericidal activities against Escherichia coli and Staphylococcus aureus of the 17 cryptdin isoforms identified by Ouellette and colleagues from a single jejunal crypt (A. J. Ouellette et al., Infect Immun 62:5040-5047, 1994), along with linearized analogs of Crp1, Crp4, and Crp14. In addition, we analyzed the most potent and weakest cryptdins in the panel with respect to their ability to self-associate in solution. Finally, we solved, for the first time, the high-resolution crystal structure of a cryptdin, Crp14, and performed molecular dynamics simulation on Crp14 and a hypothetical mutant, T14K-Crp14. Our results indicate that mutational effects are highly dependent on cryptdin sequence, residue position, and bacterial strain. Crp14 adopts a disulfide-stabilized, three-stranded ß-sheet core structure and forms a noncanonical dimer stabilized by asymmetrical interactions between the two ß1 strands in parallel. The killing of E. coli by cryptdins is generally independent of their tertiary and quaternary structures that are important for the killing of S. aureus, which is indicative of two distinct mechanisms of action. Importantly, sequence variations impact the bactericidal activity of cryptdins by influencing their ability to self-associate in solution. This study expands our current understanding of how cryptdins function at the molecular level.

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BACKGROUND: Due to the benefits of blenderized tube feeding (BTF) diets, the interest in using them is increasing. This study aimed to design BTFs for children and investigate their physicochemical and microbial properties, as well as Dietary Inflammatory Index (DII). METHODS: Five BTF diets were formulated mainly with fresh foods; their DII, physical (viscosity), and chemical (moisture, ash, protein, fat, energy, and micronutrients) characteristics were assessed. Also, the Hazard Analysis and Critical Control Points (HACCP) system was implemented for quality assurance of preparation, storage, and delivery of BTFs to patients in hospital. The microbial contamination (total count, Salmonella, Escherichia coli, Bacillus cereus, Listeria monocytogenes, coliforms, Staphylococcus aureus coagulase positive, mold, and yeast) was analyzed. RESULTS: Energy and percentages of protein, fat, and carbohydrate in BTFs were in the range of 103-112 kcal/100 ml, 16%-22%, 28%-34%, and 48%-52%, respectively. The viscosity of the five developed BTFs was between 29 and 64 centipoises, which allows the formulas to flow without syringe pressure. The DII of all BTFs was between -0.73 and -2.24. Due to the implementation of HACCP, monitoring the production line of BTFs, and performance of corrective measures, no microbial contamination was observed by indicator pathogenic microorganisms. CONCLUSION: A planned BTF diet can be an excellent selection for children using enteral nutrition with tube feeding especially when they are made from fresh and anti-inflammatory foods such as recipes prepared in this study.

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As one of the most widely used assays in biological research, an enumeration of the bacterial cell colonies is an important but time-consuming and labor-intensive process. To speed up the colony counting, a machine learning method is presented for counting the colony forming units (CFUs), which is referred to as CFUCounter. This cell-counting program processes digital images and segments bacterial colonies. The algorithm combines unsupervised machine learning, iterative adaptive thresholding, and local-minima-based watershed segmentation to enable an accurate and robust cell counting. Compared to a manual counting method, CFUCounter supports color-based CFU classification, allows plates containing heterologous colonies to be counted individually, and demonstrates overall performance (slope 0.996, SD 0.013, 95%CI: 0.97-1.02, p value < 1e-11, r = 0.999) indistinguishable from the gold standard of point-and-click counting. This CFUCounter application is open-source and easy to use as a unique addition to the arsenal of colony-counting tools.

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Objective: To investigate compatibility, stability, and microbiologic risk of omadacycline 1 mg/mL when prepared in an elastomeric infusion pump and stored under refrigeration for 9 days based upon requests for information from healthcare providers. Methods: Omadacycline was reconstituted to 1 mg/mL with sodium chloride 0.9% w/v or dextrose 5% w/v in SMARTeZ® elastomeric infusion pumps and refrigerated for up to 9 days. Samples were taken daily and tested for appearance, pH, osmolality, chemical composition, and particulate matter. For a microbial challenge study, the pumps were spiked with a challenge microorganism (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, or Aspergillus brasiliensis) and samples were plated daily for 9 days to assess microbial survival. Results: Appearance, pH, osmolality, percent label claim, and particulate matter results remained essentially unchanged for omadacycline solutions in either diluent over the 9-day study. No > 0.5-log day-to-day increases in the challenge-microorganism populations were measured in diluted omadacycline pumps or positive controls. With omadacycline, no growth was seen for S. aureus or E. coli in either diluent, nor for P. aeruginosa in dextrose 5% w/v. Reduction of C. albicans and A. brasiliensis populations over time was similar between omadacycline solutions and positive controls. Conclusion: After reconstitution, omadacycline for injection was stable and remained within specifications for use for up to 9 days when refrigerated.

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Interventions from lairage to the chilling stage of the pig slaughter process are important to reduce microbial contamination of carcasses. The aim of this systematic review and meta-analysis was to assess the effectiveness of abattoir interventions in reducing aerobic colony count (ACC), Enterobacteriaceae, generic Escherichia coli, and Yersinia spp. on pig carcasses. The database searches spanned a 30 year period from 1990 to 2021. Following a structured, predefined protocol, 22 articles, which were judged as having a low risk of bias, were used for detailed data extraction and meta-analysis. The meta-analysis included data on lairage interventions for live pigs, standard processing procedures for pig carcasses, prechilling interventions, multiple carcass interventions, and carcass chilling. Risk ratios (RRs) for prevalence studies and mean log differences (MDs) for concentration outcomes were calculated using random effects models. The meta-analysis found that scalding under commercial abattoir conditions effectively reduced the prevalence of Enterobacteriaceae (RR: 0.05, 95% CI: 0.02 to 0.12, I2 = 87%) and ACC (MD: -2.84, 95% CI: -3.50 to -2.18, I2 = 99%) on pig carcasses. Similarly, significant reductions of these two groups of bacteria on carcasses were also found after singeing (RR: 0.25, 95% CI: 0.14 to 0.44, I2 = 90% and MD: -1.95, 95% CI: -2.40 to -1.50, I2 = 96%, respectively). Rectum sealing effectively reduces the prevalence of Y. enterocolitica on pig carcasses (RR: 0.60, 95% CI: 0.41 to 0.89, I2 = 0%). Under commercial abattoir conditions, hot water washing significantly reduced ACC (MD: -1.32, 95% CI: -1.93 to -0.71, I2 = 93%) and generic E. coli counts (MD: -1.23, 95% CI: -1.89 to -0.57, I2 = 61%) on pig carcasses. Conventional dry chilling reduced Enterobacteriaceae prevalence on pig carcasses (RR: 0.32, 95% CI: 0.21 to 0.48, I2 = 81%). Multiple carcass interventions significantly reduced Enterobacteriaceae prevalence (RR: 0.11, 95% CI: 0.05 to 0.23, I2 = 94%) and ACC on carcasses (MD: -2.85, 95% CI: -3.33 to -2.37, I2 = 97%). The results clearly show that standard processing procedures of scalding and singeing and the hazard-based intervention of hot water washing are effective in reducing indicator bacteria on pig carcasses. The prevalence of Y. enterocolitica on pig carcasses was effectively reduced by the standard procedure of rectum sealing; nevertheless, this was the only intervention for Yersinia investigated under commercial conditions. High heterogeneity among studies and trials investigating interventions and overall lack of large, controlled trials conducted under commercial conditions suggest that more in-depth research is needed.

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The presence of a microgap along an implant-abutment connection (IAC) is considered the main disadvantage of two-piece implant systems. Its existence may lead to mechanical and biological complications. Different IAC designs have been developed to minimise microleakage through the microgap and to increase the stability of prosthodontic abutments. Furthermore, different sealing materials have appeared on the market to seal the gap at the IAC. The purpose of this study was to evaluate the antimicrobial efficacy and permeability of different materials designed to seal the microgap, and their behaviour in conical and straight types of internal IACs. One hundred dental implants with original prosthodontic abutments were divided into two groups of fifty implants according to the type of IAC. Three different sealing materials (GapSeal, Flow.sil, and Oxysafe gel) were applied in the test subgroups. The contamination of implant-abutment assemblies was performed by a joint suspension containing Candida albicans and Staphylococcus aureus. It was concluded that the IAC type had no significant influence on microleakage regarding microbial infection. No significant difference was found between the various sealing agents. Only one sealing agent (GapSeal) was found to significantly prevent microleakage. A complete hermetic seal was not achieved with any of the sealing agents tested in this study.

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BACKGROUND: Guidelines for the reuse of enteral tube feeding (ETF) equipment guidelines are limited to manufacturer recommendations. ETF equipment reuse studies are needed as the enteral population has increased, along with blenderized tube feeding (BTF). METHODS: This experiment tested microbial contamination of a reusable gravity feeding bag and syringe after 15 BTF reuses and cleanings. Eight bags and syringes were filled with the BTF, held at room temperature for 20 min, and then emptied, washed, and air dried. After the last air drying, the inner surfaces of the bag and syringe were swabbed, and aerobic microbial counts were performed using serial dilutions and plate counts. RESULTS: The microbial counts for all syringes and six bags were <1 colony-forming unit (CFU)/cm2 ; one bag was <5 CFU/cm2 and one bag was 12.5 CFU/cm2 . No legal guidelines for surface cleanliness exist for the food sector. Several studies propose a safe microbial level to be <2.5 CFU/cm2 , and the European Commission recommended <10 CFU/cm2 . Based on these proposed guidelines, microbial counts of all syringes and seven bags were within the proposed guidelines, except for one bag just above 10 CFU/cm2 . CONCLUSION: The feeding bag used in this study may be used multiple times for BTF with a reduced risk of microbial contamination when manufacturer's cleaning guidelines are followed. Although bolus tube feeding is an off-label use for syringes, they are frequently used for BTF, and in this study the cleaning after 15 uses over 5 days was effective to reduce microbial counts.

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Implant-abutment connection (IAC) is a key factor for the long-term success and stability of implant-supported prosthodontic restoration and its surrounding tissues. Misfit between prosthodontic abutment and implant at the IAC leads to technical and biological complications. Two kinds of prosthodontic abutments are currently available on the market: original and third-party abutments. The aim of this pilot study was to test and compare the internal fit (gap) at the implant-abutment interface depending on the abutment fabrication method based on microbial leakage in static conditions and the need for the use of gap sealing material. Two groups of 40 implants were formed on the basis of the type of abutment. In each of the groups of two implant systems, two subgroups of 10 implants were formed. The tested subgroups consisted of 10 implants with sealing material and a negative control subgroups consisting of 10 implants without any sealing material. The test material, GapSeal (Hager and Werken, Duisburg, Germany) was applied in the test subgroups. The implant-abutment assemblies were contaminated with a solution containing Staphylococcus aureus and Candida albicans for 14 days under aerobic conditions. Results showed that there was no statistically significant difference regarding the microbial leakage between the original and third-party custom-made abutments, regardless of the use of sealing material. It can be concluded that the abutment fabrication method has no significant influence on sealing efficacy regarding the bacterial and fungal leakage in static conditions.

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Groundwater is an important water source to consider when ensuring the safety of urban water supply. Groundwater contaminated by bacteria poses a potential health risk to the drinking water supply. This study focuses on the water supply of Liuzhou City, a famous industrial city in China. Analyses of the concentrations, spatial distribution, and pollution sources of bacteria in the groundwater were conducted based on samples collected from 27 wells during the wet and dry seasons in 2018. The total colony counts and total coliform were high during both the wet and dry seasons, posing a severe threat to the emergency water supply security for more than one million people in the city. The groundwater in Liuzhou City is generally contaminated by bacteria, with higher pollution levels in the northern urban-rural fringe and central urban areas. Domestic pollution is the main sources of groundwater bacteria. In addition, bacterially contaminated rivers (Liujiang River) passing through the urban area likely transfer bacteria to the groundwater due to the circulation of the groundwater and surface river water. Controlling the bacterial pollution of groundwater in this region requires adherence to a long-term management plan.

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The gold standard for quantifying bacteria both in routine diagnostics and in research is plating followed by count of colony-forming units (CFU). But, manual CFU counting on plates is time-consuming and subjective. We evaluated fractal dimension as a new methodology for evaluating CFU. Twenty fragments of expanded polytetrafluoroethylene (ePTFE) synthetic vascular prosthesis and 20 silicone prostheses were embedded in bacterial suspensions and incubated. The prostheses were then sown in solid culture medium and incubated for 48 h. Petri dishes were photographed and analyzed by fractal dimension. There was correlation between the number of CFU in manual counting and the fractal dimension analysis (p = 0.0001). We demonstrated that fractal dimension is a useful method for microbiological analyses in researches. It makes CFU analysis easier and faster and can be used regardless of the culture medium.•Petri dishes with different bacterial colonies were photographed with a digital camera under natural light.•The images were binarized and analyzed with ImageJⓇ's "fractal dimension" tool.•Fractal dimension analysis showed to be a good tool for evaluating the amount of colony-forming unit.