Log Colony-forming Units Research Articles

Evaluation of aloe vera gel as a local drug delivery agent in the treatment of chronic periodontitis: A clinical and microbiological study

Abstract Background: Local delivery of antibacterial agents into periodontal pockets provides a multitude of benefits over systemic antimicrobials resulting in the increased preference for such use among periodontal health-care providers. Aim: The study aims to determine the antimicrobial efficacy of adjunctive use of the herbal extract “aloe vera gel” (Aloe vera (L.) Burm. f.) along with scaling and root planing (SRP) in patients with chronic periodontitis. Materials and methods: This prospective, single-blind randomized split-mouth clinical trial was done among 22 subjects diagnosed with chronic periodontitis. Periodontal parameters and mean log counts of porphyromonas gingivalis (P. gingivalis) evaluated using real-time polymerase chain reaction were recorded. SRP was performed both at control and test sites. The evaluation of clinical and microbiological parameters was done at baseline and 3 months’ post-intervention. Data were analyzed using Statistical Package for Social Sciences (SPSS) V.20 software. Results: While significant improvement in both clinical and microbiological parameters from baseline to three months was observed in both the test and control sites, the mean reduction in plaque index, periodontal pocket depth, and mean log colony-forming unit counts of P. gingivalis were significantly higher in the test sites compared to the control sites. Conclusion: The results of this study reject the null hypothesis in favor of the alternative hypothesis that adjunctive application of locally delivered aloe vera gel for the treatment of chronic periodontitis enhances the beneficial effects of mechanical therapy.

The heme oxygenase-1 metalloporphyrin inhibitor stannsoporfin enhances the bactericidal activity of a novel regimen for multidrug-resistant tuberculosis in a murine model.

Multidrug-resistant (MDR) Mycobacterium tuberculosis (Mtb) poses significant challenges to global tuberculosis (TB) control efforts. Host-directed therapies (HDTs) offer a novel approach to TB treatment by enhancing immune-mediated clearance of Mtb. Prior preclinical studies found that the inhibition of heme oxygenase-1 (HO-1), an enzyme involved in heme metabolism, with tin-protoporphyrin IX (SnPP) significantly reduced mouse lung bacillary burden when co-administered with the first-line antitubercular regimen. Here, we evaluated the adjunctive HDT activity of a novel HO-1 inhibitor, stannsoporfin (SnMP), in combination with a novel MDR-TB regimen comprising a next-generation diarylquinoline, TBAJ-876 (S), pretomanid (Pa), and a new oxazolidinone, TBI-223 (O) (collectively, SPaO), in Mtb-infected BALB/c mice. After 4 weeks of treatment, SPaO + SnMP 5mg/kg reduced mean lung bacillary burden by an additional 0.69 log10 (P = 0.01) relative to SPaO alone. As early as 2 weeks post-treatment initiation, SnMP adjunctive therapy differentially altered the expression of pro-inflammatory cytokine genes and CD38, a marker of M1 macrophages. Next, we evaluated the sterilizing potential of SnMP adjunctive therapy in a mouse model of microbiological relapse. After 6 weeks of treatment, SPaO + SnMP 10mg/kg reduced lung bacterial burdens to 0.71 ± 0.23 log10 colony-forming units (CFUs), a 0.78 log-fold greater decrease in lung CFU compared to SpaO alone (P = 0.005). However, adjunctive SnMP did not reduce microbiological relapse rates after 5 or 6 weeks of treatment. SnMP was well tolerated and did not significantly alter gross or histological lung pathology. SnMP is a promising HDT candidate requiring further study in combination with regimens for drug-resistant TB.

Assessment of Microgap and Bacterial Leakage of Two Types of Internal Implant-Abutment Union.

The current research was done to assess microbial seepage of two types of internal implant-abutment connections. Twenty dental implants are categorized into two groups. Group A fixtures with an internal hexagonal geometry and group B fixtures with a tri-lobe internal connection. All implant-abutment assemblies underwent a three-week incubation period at 37°C in sterile tubes containing 5 mL of Staphylococcus aureus broth culture. Through the use of Gram stain and biochemical processes, the resultant colonies were recognized. The mean Log10 colony forming unit (CFU) in group A was 8.4 and in group B was 7.2. The variation between both groups was found to be considerable (P < 0.05). Microgap was more in group B compared to group A. Bacteria may infiltrate the small area between the implant and the abutment. Compared to dental implant fixtures with a tri-lobe internal connection, there was a noticeably higher Log10 CFU in dental implant fixtures with an internal hexagonal geometry.

Novel lactoferrin-conjugated gallium complex to treat Pseudomonas aeruginosa wound infection

Pseudomonas aeruginosa is one of the leading causes of opportunistic infections such as chronic wound infection that could lead to multiple organ failure and death. Gallium (Ga3+) ions are known to inhibit P. aeruginosa growth and biofilm formation but require carrier for localized controlled delivery. Lactoferrin (LTf), a two-lobed protein, can deliver Ga3+ at sites of infection. This study aimed to develop a Ga-LTf complex for the treatment of wound infection. The characterisation of the Ga-LTf complex was conducted using differential scanning calorimetry (DSC), Infra-Red (FTIR) and Inductive Coupled Plasma Optical Emission Spectrometry (ICP-OES). The antibacterial activity was assessed by agar disc diffusion, liquid broth and biofilm inhibition assays using the colony forming units (CFUs). The healing capacity and biocompatibility were evaluated using a P.aeruginosa infected wound in a rat model. DSC analyses showed thermal transition consistent with apo-lactoferrin; FTIR confirmed the complexation of gallium to lactoferrin. ICP-OES confirmed the controlled local delivery of Ga3+. Ga-LTf showed a 0.57 log10 CFUs reduction at 24 h compared with untreated control in planktonic liquid broth assay. Ga-LTf showed the highest antibiofilm activity with a 2.24 log10 CFUs reduction at 24 h. Furthermore, Ga-LTf complex is biocompatible without any adverse effect on brain, kidney, liver and spleen of rats tested in this study. Ga-LTf can be potentially promising novel therapeutic agent to treat pathogenic bacterial infections.

Microbial communities of a variety of 75 homemade fermented vegetables.

Fermentation is an ancient practice of food preservation. Fermented vegetables are popular in Eastern European and Asian countries. They have received a growing interest in Western countries, where they are mainly manufactured at domestic and artisanal scales and poorly characterized. Our aim was to investigate the microbial communities and the safety of French homemade fermented vegetables, in the frame of a citizen science project. Fermented vegetables and the data associated with their manufacture were collected from citizens and characterized for pH, NaCl concentration, and microbiology by culturomics and 16S DNA metabarcoding analysis. Lactic acid bacteria (LAB) and yeast isolates were identified by 16S rRNA gene sequencing and D1/D2 domains of the large subunit of the rRNA gene, respectively. The 75 collected samples contained 23 types of vegetables, mainly cabbage, followed by carrots and beets, and many mixtures of vegetables. They were 2 weeks to 4 years old, and their median pH was 3.56, except for two samples with a pH over 4.5. LAB represented the dominant viable bacteria. LAB concentrations ranged from non-detectable values to 8.7 log colony-forming units (CFU)/g and only depended on the age of the samples, with the highest most frequently observed in the youngest samples (<100 days). The 93 LAB isolates identified belonged to 23 species, the two mains being Lactiplantibacillus pentosus/plantarum and Levilactobacillus brevis. The other microbial groups enumerated (total aerobic bacteria, halotolerant bacteria, Gram-negative bacteria, and acetic acid bacteria) generally showed lower concentrations compared to LAB concentrations. No pathogenic bacteria were detected. Viable yeasts were observed in nearly half the samples, at concentrations reaching up to 8.0 log CFU/g. The 33 yeast clones identified belonged to 16 species. Bacterial metabarcoding showed two main orders, namely, Lactobacillales (i.e., LAB, 79% of abundance, 177 of the 398 total ASVs) and Enterobacterales (19% of abundance, 191 ASVs). Fifteen LAB genera were identified, with Lactiplantibacillus and Levilactobacillus as the most abundant, with 41 and 12% of total reads, respectively. Enterobacterales members were mainly represented by Enterobacteriaceae and Yersiniaceae. This study is the first wide description of the microbiota of a large variety of homemade fermented vegetables and documents their safety.

Targeting Biomechanical Endurance of Dental-Implant Abutments Using a Diamond-Like Carbon Coating.

Abutment components (i.e., fixtures associated with oral implants) are essentially made of titanium (Ti), which is continuously exposed to the hash oral environment, resulting in scratching. Thus, such components need to be protected, and surface treatments are viable methods for overcoming long-term damage. Diamond-like carbon (DLC), an excellent protective material, is an alternative surface-treatment material for Ti abutments. Here, we demonstrate that a silicon interlayer for DLC film growth and the pulsed-direct current plasma-enhanced chemical vapor deposition (DC-PECVD) method enables the deposition of an enhanced protective DLC film. As a result, the DLC film demonstrated a smooth topography with a compact surface. Furthermore, the DLC film enhanced the mechanical (load-displacement, hardness, and elastic modulus) and tribological properties of Ti as well as increased its corrosion resistance (16-fold), which surpassed that of a bare Ti substrate. The biofilm formed (Streptococcus sanguinis) after 24 h exhibited an equal bacterial load (∼7 Log colony-forming units) for both the groups (Ti and DLC). In addition, the DLC film exhibited good cytocompatibility, owing to its noncytotoxicity toward human gingival fibroblast cells. Therefore, DLC deposition via DC-PECVD can be considered to be a promising protective and cytocompatible alternative for developing implant abutments with enhanced mechanical, tribological, and electrochemical properties.

Fosfomycin activity in vitro against Escherichia coli strains isolated from urine specimens

Abstract Urinary tract infections are caused mostly by uropathogenic Escherichia coli strains. The aim of this paper was to assess the activity of fosfomycin in vitro against 74 E. coli strains isolated from urine samples of outpatients with acute cystitis. Minimum inhibitory concentration (MIC) was determined by the recommended method of serial drug dilution in Mueller-Hinton agar supplemented with glucose-6-phosphate (25 mg/L). The estimated MIC values were in the range of 1-32 mg/L. The prevalence of fosfomycin-sensitive strains was 45.9%, while that of fosfomycin-resistant strains – 54.1%. The time-kill assay was performed for a chosen clinical strain (MIC = 1 mg/L) in Mueller-Hinton broth also supplemented with glucose-6-phosphate in the presence of various concentrations of fosfomycin (0.5-64 mg/L). The bacterial population density was expressed as log CFU (colony forming units)/mL. The decrease of the bacterial population viability after 6h incubation was found with ∆log CFU/mL = 1.05-5.02, depending on fosfomycin concentration. However, bactericidal effect of this antibiotic (∆log CFU/mL &gt;3) was observed only at the highest concentrations (32-64 mg/L). Moreover, after prolonged incubation (24 h), the re-growth of bacterial population revealed as the increase of its viability (∆log CFU/mL = 1.03-3.03) was observed at fosfomycin concentration in the range 0.5-32 mg/L, but not at 64 mg/L. This phenomenon may be due the presence of subpopulations of spontaneous mutants sensitive only to higher concentrations of this antibiotic comparing to MIC. The presented data confirm a need to monitor the sensitivity of uropathogenic E. coli strains to fosfomycin.

Ceftriaxone Efficacy for Mycobacterium avium Complex Lung Disease in the Hollow Fiber and Translation to Sustained Sputum Culture Conversion in Patients.

Only 35.6%-50.8% of patients with Mycobacterium avium complex (MAC) pulmonary disease achieve sustained sputum culture conversion (SSCC) on treatment with the azithromycin-ethambutol-rifabutin standard of care (SOC). We tested the efficacy of ceftriaxone, a β-lactam with a lung-to-serum penetration ratio of 12.18-fold. We mimicked lung concentration-time profiles of 7 ceftriaxone once-daily doses for 28 days in the hollow fiber system model of intracellular MAC (HFS-MAC). Monte Carlo experiments were used for dose selection. We also compared once-daily ceftriaxone monotherapy to 3-drug SOC against 5 MAC clinical isolates in HFS-MAC using γ (kill) slopes, and translated to SSCC rates. Ceftriaxone killed 1.02-3.82 log10 colony-forming units (CFU)/mL, at optimal dose of 2 g once-daily. Ceftriaxone killed all 5 strains below day 0 versus 2 of 5 for SOC. The median γ (95% confidence interval [CI]) was 0.49 (.47-.52) log10 CFU/mL/day for ceftriaxone and 0.38 (.34-.43) log10 CFU/mL/day for SOC. In patients, the SOC was predicted to achieve SSCC rates (CI) of 39.3% (36%-42%) at 6 months. The SOC SSCC was 50% at 8.18 (3.64-27.66) months versus 3.58 (2.20-7.23) months for ceftriaxone, shortening time to SSCC 2.35-fold. Ceftriaxone is a promising agent for creation of short-course chemotherapy.

Microbial Quality of Halawet Eljibn, an Arabic Sweet Sold in the Retail Market in Jordan

Background: Halawet eljibn is a popular Ready-to-Eat sweet in the Levant region. However, its non-machinery preparation and lack of final heating increase the risk of contamination by microorganisms that can cause food-borne illnesses. The study aimed to investigate the numbers of microorganisms present in commercially produced halawet eljibn in Jordan.&#x0D; Methods: Sixty samples of halawet eljibn were collected from 15 sweet shops in Amman, Jordan at two intervals. Two sample units were taken from each sweet shop, and two reference samples were prepared under hygienic conditions for comparison purposes. The study evaluated the chemical properties of the samples, including moisture content, pH, and titratable acidity, and also assessed their microbiological quality through Aerobic Plate Count, Coliform Count, Lactic Acid Bacteria count, Staphylococcus aureus count, and yeast and mold count analyses.&#x0D; Results: In this study, the samples exhibited a moisture content ranging from 40.9 to 49.8%, a pH range of 5.7 to 6.7, and acidity levels varying between 0.14 and 0.45%. The average Aerobic Plate Count and the counts of coliforms, Lactic Acid Bacteria, yeast and mold and S. aureus for halawet eljibn market samples were 6.6, 4.1, 6.8, 3.2, and 2.0 log Colony Forming Unit (CFU)/g, respectively. Counts of interval I (10th October-12th December) samples were significantly higher than those of interval II (19th December-10th January). The same average counts of the reference samples were significantly lower (2.3, &lt;10, 1.6, 1.4, and &lt;10 log CFU/g, respectively).&#x0D; Conclusion: The study findings indicate that halawet eljibn provides an appropriate environment for microbial growth. The observed non-adherence to optimal hygienic practices during the production and handling of halawet eljibn underscores the need for more rigorous regulations to ensure its microbiological quality and safety.

1419. Evaluation of a vaporized hydrogen peroxide sterilization technology for duodenoscopes

Abstract Background Current methods for reprocessing duodenoscopes, including double high-level disinfection, are not effective in eliminating bacterial contamination. Thus, there is a need to develop effective and safe sterilization technologies for duodenoscopes. Methods We examined the effectiveness of a new hydrogen peroxide gas plasma sterilizer designed for terminal sterilization of flexible endoscopes. The technology directs vaporized hydrogen peroxide into all internal endoscope channels with a short exposure time and includes a sterilization container that facilitates sterile storage after processing. Test organisms included Bacillus atrophaeus and Clostridioides difficile spores, Escherichia coli, Enterococcus faecium, and Candida auris inoculated on steel wires or dispersed throughout the internal channels with 5% fetal calf serum. Results The technology reduced &amp;gt;108 colony-forming units (CFU) of the vegetative organisms to undetectable levels. B. atrophaeus and C. difficile spores on steel wires were eliminated by the technology ( &amp;gt;6 log10 CFU reduction) and spores disperse throughout the channels were reduced by &amp;gt;5 log10 CFU. No damage to the endoscopes was observed. Conclusion The sterilization technology was highly effective in reducing contamination of duodenoscopes in laboratory testing. Our results support further investigation of this technology in reducing contamination of in-use endoscopes. Disclosures William Rutala, MS, MPH, PhD, Ideate Medical: Advisor/Consultant|Ideate Medical: Stocks/Bonds|Kinnos: Advisor/Consultant|Kinnos: Stocks/Bonds|PDI: Advisor/Consultant|PDI: Honoraria

Effect of Lactiplantibacillus plantarum on the Conversion of Linoleic Acid of Vegetable Oil to Conjugated Linoleic Acid, Lipolysis, and Sensory Properties of Cheddar Cheese.

Conjugated linoleic acid (CLA) is perceived to protect the body from metabolic diseases. This study was conducted to determine the effect of Lactiplantibacillus plantarum (Lp. plantarum) on CLA production and sensory characteristics of cheddar cheese. Lp. plantarum can convert linoleic acid (LA) to CLA. To increase CLA in cheddar cheese and monitor the conversion of LA to CLA by Lp. plantarum, the LA content of cheese milk (3.4% fat) was increased by partially replacing fat with safflower oil (85% LA of oil) at 0, 3, 6, and 9% concentrations (T1, T2, T3, and T4). Furthermore, Lp. plantarum 108 colony-forming units (CFU)/mL (8 log CFU mL-1) was added in all treatments along with traditional cheddar cheese culture (Lactococcus lactis ssp. lactis and L. lactis ssp. cremoris). After 30 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.75, 6.72, 6.65, and 6.55 log CFU g-1. After 60 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.35, 6.27, 6.19, and 6.32 log CFU g-1. After 60 days of ripening, Lp. plantarum in T1, T2, T3, and T4 was 6.41, 6.25, 6.69, and 6.65 log CFU g-1. GC-MS analysis showed that concentrations of CLA in the 90 days' control, T1, T2, T3, and T4 were 1.18, 2.73, 4.44, 6.24, and 9.57 mg/100 g, respectively. HPLC analysis revealed that treatments containing Lp. plantarum and LA presented higher concentrations of organic acids than the control sample. The addition of safflower oil at all concentrations did not affect cheese composition, free fatty acids (FFA), and the peroxide value (POV) of cheddar cheese. Color flavor and texture scores of experimental cheeses were not different from the control cheese. It was concluded that Lp. plantarum and safflower oil can be used to increase CLA production in cheddar cheese.

Microbial assessment of poultry farm biosecurity. Proceeding of The First International Avian Influenza Summit, University of Arkansas- October 16-17, 2023”

Biosecurity may be defined as protection from pathogens or disease. This may include the separation of the flock from living vectors or inanimate objects called fomites. While prevention of host-specific and zoonotic diseases is important, the commercial poultry industry is already preoccupied with the challenges of day-to-day operations. The purpose of this project was to illustrate how surfaces that may seem clean are heavily contaminated with microorganisms that may be responsible for human and avian diseases. We also evaluated three common intervention strategies, including disposable boot covers, foot baths, and tire disinfection. Poultry environmental samples were collected at the Texas A\&amp;M University Poultry Science Research Center, including fan shrouds, side air inlets, cool cell reservoirs, truck tires, truck floor mats, doorknobs, controller panels, a bioaerosol air sampler, and an impactor air sampler. A total of 30 samples were collected per sample type, which was homogenized, serially diluted, and spread plated onto agar media to culture total aerobes, Staphylococci, and coliform bacteria. 6.6 log10 colony-forming units cfu/cm2 of aerobic bacteria were found at the greatest concentration, followed by Staphylococci (5.6 log10 colony-forming units cfu/cm2) and coliforms (2 log10 colony-forming units cfu/cm2). This pattern was observed in most of the samples. Boot covers, foot baths, and tire disinfection were tested for efficacy. While disposable boot covers significantly reduced the number of aerobes, Staphylococci, and coliforms, as many as 300 microorganisms per cm2 still made it through to the inner boot cover. Disinfectants are commonly misused due to not properly clearing the surface prior to application or allowing the proper contact time. We found that while disinfection significantly reduced these indicator organisms, that reductions were only 10 to 100-fold, leaving many viable bacteria behind. Increased contact time from 3 seconds to 10 minutes resulted in significant reductions of aerobes and Staphylococcus. The tire wash data mirrored our foot bath data. Data was shared from previous laboratory and field trials. Less than 1% sterile poultry litter significantly reduced disinfectant efficacy across four product categories. Extended storage time of 30 weeks reduced product efficacy as well. We shared electron micrographs to illustrate how visually clean and smooth surfaces provide many hiding places for microbes, reducing disinfectant efficacy. While risk can never be reduced to zero, it may be reduced and controlled with good management practices. Cleaning and disinfection should follow a five-step process of dry cleaning, soap wash, rinse, drying, and finally disinfection. Labels should be read closely so that the product is used safely and effectively. While there are many viable products on the market, disinfecting a clean surface and following recommendations for contact time are very important to get the best results. Following best management practices such as reducing pest (insect/rodent) harborage and following your integrated pest management program will help reduce risk significantly.

Comparative Evaluation of Antimicrobial Activity of Herbal and Nonherbal Root Canal Irrigants on Enterococcus faecalis: An in vitro Study

Introduction: Enterococcus faecalis is one of the most prevalent pathogens in infected root canals. Even though the role of irrigants in controlling pathogens is well established, there is a chance for drug resistance and cytotoxicity in using chemical irrigants, Therefore newer researches have forced the man to look the herbal way. Aim of the Study: This study aims to evaluate and compare the anti-bacterial effects of nonherbal and herbal root canal irrigants on E. faecalis. Methodology: The study was conducted on 110 permanent extracted human teeth each root canal was inoculated with a culture suspension of E. faecalis and then randomly assigned into groups, (i) Herbal group (QMix™ 2 in 1, Endoseptone, Biopure MTAD) and (ii) Nonherbal group (Morinda citrifolia juice, Triphala juice, Coconut milk), and control group (Sodium hypochlorite and Distilled water). Colony forming units (CFUs) were evaluated and counted at baseline (S0), immediatedly after irrigation (S1) and after 3 days (S2). The Friedman two-way ANOVA was used to compare the obtained mean of log CFU. Results: Both the herbal and nonherbal groups had a significant reduction in the number of CFUs. The greatest anti-microbial effects were observed in nonherbal group against E. faecalis. Conclusion: While the herbal group also demonstrated significant reductions, the nonherbal group experienced the greatest overall anti-microbial effects of the various irrigants. Research into the herbal irrigants is necessary since they have the potential to be effective irrigants.

Isolation, antibacterial characterization, and alternating tangential flow–based preparation of viable cells of Lacticaseibacillus paracasei XLK 401: Potential application in milk preservation

It is desirable to obtain high levels of viable Lacticaseibacillus paracasei, a widely used food probiotic whose antibacterial activity and potential application in milk remain largely uninvestigated. Here, we isolated and purified the L. paracasei strain XLK 401 from food-grade blueberry ferments and found that it exhibited strong antibacterial activity against both gram-positive and gram-negative foodborne pathogens, including Staphylococcus aureus, Salmonella paratyphi B, Escherichia coli O157, and Shigella flexneri. Then, we applied alternating tangential flow (ATF) technology to produce viable L. paracasei XLK 401 cells and its cell-free supernatant (CFS). Compared with the conventional fed-batch method, 22 h of ATF-based processing markedly increased the number of viable cells of L. paracasei XLK 401 to 12.14 ± 0.13 log cfu/mL. Additionally, the CFS exhibited good thermal stability and pH tolerance, inhibiting biofilm formation in the abovementioned foodborne pathogens. According to liquid chromatography-mass spectrometry analysis, organic acids were the main antibacterial components of XLK 401 CFS, accounting for its inhibition activity. Moreover, the CFS of L. paracasei XLK 401 effectively inhibited the growth of multidrug-resistant gram-positive Staph. aureus and gram-negative E. coli O157 pathogens in milk, and caused a reduction in the pathogenic cell counts by 6 to 7 log cfu/mL compared with untreated control, thus considerably maintaining the safety of milk samples. For the first time to our knowledge, ATF-based technology was employed to obtain viable L. paracasei on a large scale, and its CFS could serve as a broad-spectrum biopreservative for potential application against foodborne pathogens in milk products.

Effects of Fumigation on the Reduction of Salmonella enterica in Soil.

Due to the phaseout of methyl bromide (MeBr), there is a need for broad-spectrum soil fumigation alternatives for pest management. Little is known about the impact of fumigation alternatives on foodborne pathogens, such as Salmonella, in agricultural soils. This study investigated the effect of MeBr alternative fumigants on Salmonella reduction in soil. Sandy loam soil was collected from a conventional farmed vegetable field and inoculated with either Salmonella Newport J1892 or Typhimurium ATCC 14028 (5.9 ± 0.3 log10 colony-forming unit [CFU]/g). Each of the four fumigants labeled for pest management (1,3-dichloropropene, chloropicrin, dimethyl disulfide, and metam sodium) was applied at labeled maximum application field levels to soil in pots and stored for a 2-week period. Sterile water was used as a control. Following the 2-week period, Salmonella concentrations in soil samples were enumerated at 1, 7, 14, and 21 days postfumigation. The mean concentration of Salmonella Newport was significantly higher than that of Salmonella Typhimurium 1 day after fumigation (p = 0.015). Fumigation using 1,3-dichloropropene or dimethyl disulfide significantly reduced Salmonella Newport and Salmonella Typhimurium concentrations, compared with the sterile water control. The rate of Salmonella reduction in soil treated with dimethyl disulfide was higher (0.17 ± 0.02 log10 CFU/g/day), compared with soil treated with the other fumigants (0.10-0.12 log10 CFU/g/day). Due to the reduction of Salmonella, alternative fumigation treatments may mitigate potential Salmonella contamination in soil within farm environments.

The Anti-Caries Effects of a Novel Peptide on Dentine Caries: An In Vitro Study.

This study aimed to investigate the antibiofilm and remineralising effects of peptide GAPI on artificial dentin caries. After creating artificial carious lesions, eighty dentine blocks were randomly assigned for treatment twice daily with GAPI (GAPI group) or deionised water (control group). Both groups underwent a 7-day biochemical cycle. Scanning electron microscopy (SEM) showed S. mutans with damaged structures that partially covered the dentine in the GAPI group. The dead-live ratios for the GAPI and control groups were 0.77 ± 0.13 and 0.37 ± 0.09 (p < 0.001). The log colony-forming units for the GAPI and control groups were 7.45 ± 0.32 and 8.74 ± 0.50 (p < 0.001), respectively. The lesion depths for the GAPI and control groups were 151 ± 18 µm and 214 ± 15 µm (p < 0.001), respectively. The mineral losses for the GAPI and control groups were 0.91 ± 0.07 gHAcm-3 and 1.01 ± 0.07 gHAcm-3 (p = 0.01), respectively. The hydrogen-to-amide I ratios for the GAPI and control groups were 2.92 ± 0.82 and 1.83 ± 0.73 (p = 0.014), respectively. SEM micrographs revealed fewer exposed dentine collagen fibres in the GAPI group compared to those in the control group. Furthermore, X-ray diffraction (XRD) patterns indicated that the hydroxyapatite in the GAPI group was more crystallised than that in the control group. This study demonstrated GAPI's antibiofilm and remineralising effects on artificial dentin caries.

Colistin Resistance in Multidrug-Resistant Escherichia coli Isolated from Retail Broiler Meat in Bangladesh.

The emergence of colistin resistance in Escherichia coli is a global public health concern. Contaminated food can accelerate the spread of colistin-resistant E. coli to humans. This study aimed to detect and characterize colistin-resistant E. coli from broiler meat in Bangladesh. We analyzed 136 pooled broiler meat samples from 240 carcasses collected from 40 live bird markets in urban and rural areas and 8 metropolitan supermarkets. The mean count of E. coli in broiler meat samples collected from rural retail shops, metropolitan supermarkets, and urban retail shops was 5.3 ± 1.1, 4.1 ± 1.4, and 3.9 ± 0.8 log10 colony-forming unit per gram, respectively. Colistin-resistant E. coli (minimum inhibitory concentration >2 mg/L) was found in 78% (95% confidence interval 70.2-84.1%) of the samples. All colistin-resistant isolates harbored the mcr-1 gene, while the rest of the mcr genes (mcr-2 to mcr-9) were not detected. Most colistin-resistant E. coli isolates (98%) showed coresistance to tetracycline, sulfamethoxazole/trimethoprim followed by ciprofloxacin (95%). Alarmingly, all of the colistin-resistant isolates were found to be multidrug resistant. Phylogenetic analysis showed close similarities of the mcr-1 gene sequences of this study with many strains of Enterobacterales isolated from humans, animals, and the environment. This study detected colistin-resistant E. coli contamination in broiler meat, which can pose a serious public health threat.

A comparative study on the antifungal effect of potassium sorbate, chitosan, and nano-chitosan against Rhodotorula mucilaginosa and Candida albicans in skim milk acid-coagulated (Karish) cheese.

Yeasts are common contaminants in the cheese industry, which frequently arise from raw milk, the surrounding environment, and equipment, resulting in economic losses in addition to health hazards. This study aimed to compare the antifungal effect of chitosan and nano-chitosan as natural preservatives with a commonly used chemical preservative (potassium sorbate) against Rhodotorula mucilaginosa and Candida albicans. Laboratory Karish cheese was manufactured with the addition of potassium sorbate, chitosan, nano-chitosan, and their combinations at different concentrations. The survival of R. mucilaginosa and C. albicans was monitored in different treatments (CR, PR1, PR2, CR1, CR2, NR1, NR2, MR, CC, PC1, PC2, CC1, CC2, NC1, NC2, MC) during storage in a refrigerator with continuous measurement of pH. The impact of using these antifungal agents on the organoleptic parameters of Karish cheese during storage was also evaluated. There was a significant decrease in the count of yeasts in all treatments from the 3rd day of storage, while the mixture of 0.1% potassium sorbate (MR) and 2% chitosan (MC) improved the antifungal effect of chitosan with a lower potassium sorbate concentration and showed the best antifungal effects against both R. mucilaginosa and C. albicans. This combination reduced the yeast count from 8.92 and 9.57 log10 colony-forming unit (CFU)/g in MR and MC treatments, respectively, until it became undetectable on the 9th day of storage, which was earlier than for all other treatments. It was noted that the addition of chitosan nanoparticles (ChNPs) at either 0.25% (NR1 and NC1) or 0.5% (NR2 and NC2) during the manufacturing of Karish cheese significantly lowered the counts of R. mucilaginosa and C. albicans compared with chitosan with a higher molecular weight, but significantly lower than potassium sorbate until 6th day of storage as all treatments of chitosan nanoparticles became significantly higher than potassium sorbate treatments. After 9 days of storage, NR2 and NC2 treatments showed the most significant decreases in count (3.78 and 4.93 log10 CFU/g, respectively), indicating better stability of ChNPs. At the end of the storage period, PR2, PC2, CR2, and CC2 showed significantly high pH values among the groups of 4.8, 5.0, 4.8, and 5.1, respectively. The overall acceptability was significantly higher in treated Karish cheese samples than in the control group, especially at the end of the storage period. Potassium sorbate, chitosan, and ChNPs are effective antifungal preservatives against R. mucilaginosa and C. albicans. In addition, the combination of chitosan with potassium sorbate showed synergistic antifungal activity. These additives also preserve the sensorial criteria longer than for cheese without preservatives.

Intracellular bacterial eradication using a novel peptide in vitro.

To determine the effect of a novel antimicrobial peptide (AMP; OP145) and cell-penetrating peptide (Octa-arginine/R8) conjugate on the killing of intracellular Enterococcus faecalis, compared to OP145 and an antibiotic combination recommended for regenerative endodontic procedures. The biocompatible concentrations of OP145 and OP145-R8 were determined by assessing their cytotoxicity against human macrophages and red blood cells. Spatiotemporal internalization of the peptides into macrophages was investigated qualitatively and quantitatively by confocal laser scanning microscopy and flow cytometry respectively. Killing of extracellular and intracellular E. faecalis OG1RF by the peptides was determined by counting the colony-forming units (CFU). Intracellular antibacterial activity of the peptides was compared to a double antibiotic combination. Confocal microscopy was used to confirm the intracellular bacterial eradication. Significant differences between the different test groups were analysed using one-way analysis of variance. p < .05 was considered to be statistically significant. Peptides at a concentration of 7.5 μmol/L were chosen for subsequent experiments based on the results of the alamarBlue™ cell viability assay and haemolytic assay. OP145-R8 selectively internalized into lysosomal compartments and the cytosol of macrophages. Conjugation with R8 improved the internalization of OP145 into macrophages in a temporal manner (70.53% at 1 h to 77.13% at 2 h), while no temporal increase was observed for OP145 alone (60.53% at 1 h with no increase at 2 h). OP145-R8 demonstrated significantly greater extracellular and intracellular antibacterial activity compared to OP145 at all investigated time-points and concentrations (p < .05). OP145-R8 at 7.5 μmol/L eradicated intracellular E. faecalis after 2 h (3.5 log reduction compared to the control; p < .05), while the antibiotics could not reduce more than 0.5 log CFU compared to the control (p > .05). Confocal microscopy showed complete absence of E. faecalis within the OP145-R8 treated macrophages. The results of this study demonstrated that the conjugation of an AMP OP145 to a cell-penetrating peptide R8 eradicated extracellular and intracellular E. faecalis OG1RF without toxic effects on the host cells.

Hydrogel capsules as new approach for increasing drying survival of plant biostimulant gram-negative consortium

Several plant growth–promoting bacteria (PGPB) are gram-negative, and their cell viability is affected during the bio-inoculant production. Hence, formulation-drying processes provide challenges that limit the adoption of these beneficial microorganisms in sustainable agricultural production. Among delivery system strategies for gram-negative PGPB, the encapsulating cells in biopolymeric materials are emerging as a promising alternative. This research aims to evaluate the effect of additives and crosslinking agents on the survival of the consortium of Herbaspirillum frisingense AP21, Azospirillum brasilense D7, and Rhizobium leguminosarum T88 in hydrogel capsules. Three crosslinkers and diverse potential drying protectors were tested. Calcium gluconate provides notable consortium survival advantages regarding colony-forming units (CFUs) (losses of up to 4 log CFU) compared to calcium lactate and calcium chloride (up to 6 log CFU). Additives such as skimmed milk, whey protein, and Gelita® EC improve the recovery of viable cells after the drying process, demonstrating an increase in cell survival of the three bacteria by up to 4 log CFU. The combination of these substances into a capsule prototype extends the storage stability of bacterial consortium up to 3 months at 18 ± 2 °C. This study expands the knowledge for formulating gram-negative PGPB consortium, regarding the crosslinker and drying protector relationship on encapsulation processes with drying survival and further storage stability performance.Key points• Hydrogel immobilization formulation approach for PGPB consortium• Enhancing drying survival of gram-negative PGPB consortium• Increasing storage stability of PGPB consortium at 18 °C