Colony Counts Research Articles

Efficacy of graphene nanocomposites for air disinfection in dental clinics: A randomized controlled study.

Aerosols containing disease-causing microorganisms are produced during oral diagnosis and treatment can cause secondary contamination. To investigate the use of graphene material for air disinfection in dental clinics by leveraging its adsorption and antibacterial properties. Patients who received ultrasonic cleaning at our hospital from April 2023 to April 2024. They were randomly assigned to three groups (n = 20 each): Graphene nanocomposite material suction group (Group A), ordinary filter suction group (Group B), and no air suction device group (Group C). The air quality and air colony count in the clinic rooms were assessed before, during, and after the procedure. Additionally, bacterial colony counts were obtained from the air outlets of the suction devices and the filter screens in Groups A and B. Before ultrasonic cleaning, no significant differences in air quality PM2.5 and colony counts were observed among the three groups. However, significant differences in air quality PM2.5 and colony counts were noted among the three groups during ultrasonic cleaning and after ultrasonic treatment. Additionally, the number of colonies on the exhaust port of the suction device and the surface of the filter were significantly lower in Group A than in Group B (P = 0.000 and P = 0.000, respectively). Graphene nanocomposites can effectively sterilize the air in dental clinics by exerting their antimicrobial effects and may be used to reduce secondary pollution.

Assessment of the Efficacy of Indigenously Prepared Azadirachta Indica Mouthwash on P. Gingivalis in Chronic Periodontitis Patients: A Microbiological Study

Aim: The present study aimed to compare and evaluate the antimicrobial effect of Azadirachta Indica (Neem mouthwash) to chlorhexidine mouthwash on P. gingivalis. Materials ans Methods: The subjects were divided into 2 groups. Group I included 5 subjects who used self-prepared neem mouthwash, and Group II included 5 subjects who used 0.2% chlorhexidine mouthwash. Subgingival plaque samples were taken at baseline and the 15th day after using the mouthwash and subjected to microbiological evaluation. Results: The colony forming unit (CFU) of P. gingivalis was calculated at baseline and on the 15th day after using mouthwash using the digit colony counter. A comparison of the total CFU of both mouthwashes revealed that the neem mouth was effective in reducing the microbial colonies of P. gingivalis from baseline to the 15th day. Conclusion: It was concluded that the self-prepared neem mouthwash was effective in reducing the colony-forming unit of P. gingivalis in the sub-gingival plaque samples and showed better results than the commercially available chemical-based chlorhexidine mouthwash.

A-253 Antimicrobial Susceptibility Pattern in Escherichia coli Isolated From Community-Acquired Urinary Tract Infections in the era Post-Covid-19

Abstract Background Urinary tract infections (UTI) are one of the most common infectious diseases diagnosed in the community as well as in hospitals. Community-acquired urinary tract infections caused by Escherichia coli represent the largest proportion of infectious diseases affecting women and a significant amount of oral antibiotics are prescribed daily to treat UTI in community outpatient clinics. Having knowledge of regional susceptibility data regarding E. coli is very important for selecting an appropriate empirical antibiotic. This study aimed to report the frequency and antimicrobial susceptibility of E. coli isolated from community-acquired urinary tract infections post-Covid-19 pandemic. Methods This study was a retrospective analysis from January to December 2023 based on the analysis of 24,019 uropathogens isolated from 182 outpatient health centers located in several regions of São Paulo city, Brazil. The urine samples were cultivated onto ChromID™CPS® agar plates by semi-quantitative technique using 1µL disposable loop, incubated at 35-37°C and the colony counting were read after 24h and 48h of incubation. The bacteria identification was performed by MALDI-TOF mass spectrometry (Vitek-MS), and the minimal inhibitory concentrations of antibiotics were determined using the Vitek®2 system, according to the manufacture’s recommendations. Only positive results with one bacterial species and a colony count ≥105 CFU/mL was considered for descriptive analysis. Results Of the 24,019 urine samples tested, 71.44% (17,159/24,019) were identified as Escherichia coli. The major frequency of E. coli infection occurred among women (90.48%) and the main age range was over 60 years (38.57%), while 21-30 comprised 16.5% of cases. The antimicrobial resistance profile for E. coli isolates showed 39.9% (6852/17158) of resistance to ciprofloxacin (MIC, >0.5 mg/L), 34.7% (5,921/17,075) to trimethoprim/sulfamethoxazole (MIC, >0.5 mg/L), 37.5% (6,371/17,002) to Amoxicillin/clavulanate (MIC, >8 mg/L), 8.75% (1,501/17,592) to ceftriaxone (MIC, >1 mg/L), 4.88% (837/17,138) to cefepime (MIC, >4 mg/L), 3.64% (616/16,901) to piperacillin/tazobactam (MIC, >8 mg/L), 11.07% (1,900/17,156) of gentamicin (MIC, >2 mg/L), 0.43% (74/17,158) of amikacin (MIC, >8 mg/L) and 2.23% (377/16,909) of fosfomycin (MIC, >16 mg/L). High-level of susceptibility was detected to carbapenems with 99.94% (10/17159) to ertapenem (MIC, ≤0.5 mg/L) and 99.8% (4/17,159) to meropenem (MIC, ≤2 mg/L). The rate of Extended-spectrum beta-lactamase production was 8.1% (1391/17159). Conclusions This data could be used locally with other related samples, to properly interpret significant resistance patterns and choose the most appropriate antimicrobial for empirical treatment of patients with community-acquired urinary tract infections.

A-255 Microbiological Profile and Frequency Distribution of Uropathogens in Brazilian Public Hospitals. Data From a Clinical Laboratory (2018-2023)

Abstract Background Urinary tract infections (UTIs) are among the most common infectious diseases in humans and represent a critical health problem, especially due to a significant rise in global antibiotic use in recent years. The purpose of this study was to describe the main uropathogens and determine the antimicrobial resistance profiles among inpatients at public hospitals in the largest city in Brazil, comparing three different epidemiological periods: pre-Covid-19 (2018-2019), Covid-19 (2020-2021) and post-Covid-19 (2022-2023). Methods A 6-year retrospective review of laboratory data from 12 public hospitals of São Paulo city from January 2018 to December 2023. The urine samples were cultivated onto ChromID® CPS agar plates and then incubated at 35°C for 18-24 h. The bacteria identification was performed by MALDI-TOF mass spectrometry (Vitek-MS), and the minimal inhibitory concentrations of antibiotics were determined using the Vitek®2 system. Only positive results with one bacterial species and a colony count ≥ 105 CFU/mL was considered for descriptive analysis. Results In the 6-year period, a total of 58,738 microorganisms from hospitalized patients were included. The frequency of isolates detected during the period were: 33.9% (19,338/58,738) in pre-Covid-19, 30.1% (17,688/58,738) in Covid-19 and 36.9% (21,712/58,738) in post-Covid-19 period. The top ten microorganisms’ prevalence detected in pre-Covid-19, Covid-19 and post-Covid-19 periods were as follow: 23,951 Escherichia coli (47.5%; 37.1%; 37.7%), 9,247 Klebsiella pneumoniae (12.5%; 14.3%; 19.8%), 7,640 Candida spp. (8.8%; 19.2%; 11.7%), 5,476 Enterococcus spp. (8%; 10%; 9.9%), 3,101 Proteus mirabilis (5.56%; 4.9%; 5.4%), 2,166 Pseudomonas aeruginosa (3.3%; 3.5%; 4.1%), 1,252 Coagulase-Negative Staphylococcus (CoNS) (2.5%; 1.6%; 2.2%), 1,166 Enterobacter spp. (2.3%; 2.1%; 1.6%), 1,088 Streptococcus spp. (3.6%; 1.2%; 0.8%) and 758 Acinetobacter spp. (0.8%; 1.5%; 1.5%). Extended spectrum beta-lactamase rates for E. coli were 16.8% and 20.2% and for K. pneumoniae were 65.7% and 65.2% in Covid-19 and Post-Covid-19 periods, respectively. The resistance to carbapenems was observed mainly in Acinetobacter spp. (85.7%, 93.8% and 80.7%), K. pneumoniae (38.3%, 42.6% and 47.3%), Pseudomonas aeruginosa (22.3%, 23.1% and 25%), and Proteus spp. (0.2%, 1.9% and 5%). Between the Gram-positive cocci, the resistance to vancomycin was observed mainly in E. faecium (43.5%, 37.5%, 30.2%) and the resistance to methicillin was detected in S. aureus (30.1%, 35.8%, 34.1%) and CoNS (31.9%, 47.8%, 53.5%). Conclusions In this study, we observed an increase in the incidence of Candida spp. coinciding with the start of the pandemic period. Overall, the frequency of uropathogens isolated from hospital centers increased and exhibited high resistance to various classes of antimicrobial agents. ESBL-producing K. pneumoniae and Carbapenem-resistant Enterobacteriacea, and nonfermenters such as Acinetobacter spp. and P. aeruginosa constitute serious problems in Brazilian hospitals.

Profiling hypoxia signaling reveals a lncRNA signature contributing to immunosuppression in high-grade glioma.

Hypoxic conditions in glioma are linked to tumor aggressiveness, poor prognosis, and treatment resistance. Long non-coding RNAs (lncRNAs) play key roles in the hypoxic and immune microenvironment of cancers, but their link to hypoxia-induced immunosuppression in high-grade glioma (HGG) is not well-studied. Gene expression profiles from TCGA and CGGA, along with clinical and genomic data, were analyzed. Bioinformatics methods including Consensus Clustering, Pearson correlation, and Cox regression analyses were used. Cell proliferation was assessed using cell counting kit-8 and colony formation assays. Glioma-macrophage interactions were evaluated using a co-culture model. Hypoxia subtype clustering showed hypoxic stress correlates with worse HGG prognosis. Eight hypoxia-related lncRNAs (AP000695.4, OSMR-AS1, AC078883.3, RP11-545E17.3, LINC01057, LINC01503, TP73-AS1, and LINC00672) with prognostic value were identified, forming a risk signature that separated patients into distinct prognostic groups. Multivariate Cox regression confirmed the signature as an independent prognostic factor. High-risk patients had greater hypoxia, leading to an immunosuppressive environment and immunotherapy resistance via tumor-associated macrophages (TAMs). TP73-AS1 significantly influenced hypoxia-induced TAM infiltration and M2 polarization. We profiled hypoxic stress in HGG and developed an 8-lncRNA hypoxia-related signature predicting patient survival and immunotherapy response, emphasizing its role in hypoxia-induced immunosuppression.

Effect of pH on the microstructure and antibacterial properties of MgO nanoparticles by microwave-assisted solution combustion

The application of magnesium oxide (MgO) nanoparticles as a candidate material for antibacterial purposes has been limited by their relatively low antibacterial activity. In this study, antibacterial MgO nanoparticles were synthesised in one step using magnesium nitrate and citric acid as raw materials using an economical and environmentally friendly microwave-assisted solution combustion approach, while the effect of the pH of the reaction system (2, 4, and 7) on the structure and antimicrobial properties of the synthesised MgO nanoparticles was investigated. X-ray diffraction (XRD) analysis demonstrated the formation of cubic-phase MgO nanoparticles, and electron microscopy studies confirmed that MgO nanoparticles synthesised at a precursor solution pH of 4 had uniform size distribution with a small microcrystalline size (∼19 nm) and spherical granular morphology. In addition, the results of the plate colony counting method showed that the antibacterial rate of MgO-4 against Gram-negative Escherichia coli (106 CFU/mL) at a sample concentration of 100 μg/mL was as high as 99.86 %, which showed excellent antibacterial performance. These findings provide valuable insights into how to increase the degree of oxygen adsorption on the sample surface to participate in the reaction, as well as a potential method for constructing nanomaterials with high antimicrobial activity.

Lag Plot: A Novel Method to Determine Viable Bacterial Cell Number via a Single OD Measurement.

Bactericidal activity is a valuable parameter which is considered and measured for antimicrobial compounds. The available standard protocol to evaluate bactericidal activity is based on the direct colony count. Colony counting requires serial dilution, plating, overnight incubation, and direct counting, which is time-and labor-intensive. In regard to eliminate direct plate count, novel techniques were developed based on the real-time growth monitoring which can come with some limitations and drawbacks. These drawbacks encourage us to develop a novel technique with simple procedure to determine viable bacterial cell count. In this procedure, real-time growth monitoring is not required. In fact, after an incubation time, the number of viable bacteria can be determined with a single OD measurement and through an equation. In this regard, four standard bacterial strains, including Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), and Bacillus subtilis (ATCC 23857), were cultured with descending inoculum densities (1.5 × 107 to 15CFU/mL) and growth curves were drawn. As expected, growth in the samples with lower inoculum densities recorded with longer lag phase. Also, a direct relation was observed between the recorded turbidities and initial cell counts. A logarithmic curve (lag plot) was obtained by plotting the OD, after 12-18h incubation, against initial cell counts. In all examined strains, R2 was calculated in the range of 0.96-0.99 which is acceptable value for coefficient of determination. Equation corresponding to the lag plot was obtained and called lag equation. This equation is applicable to calculate the number of viable cells in unknown samples simply by inoculation, incubation, and single OD measurement. Developed technique can be introduced as a simple substitution for labor- and time-intensive direct colony counting.

Microbiological stability of Hermetia illucens meal subjected to two different heat treatments

The use of processed insect proteins for poultry and pig feed has been authorized since August 2021 (Regulation EU, 2021/1372). It has been already authorized for aquaculture since 2017 (Regulation EU, 2017/893). The adoption of this Regulation has boosted the European insect industry. However, there is currently little information regarding the evaluation of the shelf-life of insect-based feeds. The present work analyzed meals of Hermetia illucens that underwent two different treatments. The first treatment involved pre-sterilization at 80 °C for 2 h, and after that the larvae were subjected to treatment at 65 °C. The second treatment consisting in a heat treatment at 65 °C without pre-sterilization. The analysis performed for specific microbiological parameters, such as presence of β-glucuronidase positive Escherichia coli, Enterobacteriaceae, colony count at 30 °C, Salmonella spp., Listeria monocytogenes, Bacillus cereus, Clostridium perfringens, coagulase-positive Staphylococcus, yeasts and moulds, did not reveal any concerns about bacteria counts or pathogen presence.

Bio-based polylactic acid labware as a sustainable alternative for microbial cultivation in life science laboratories

Single-use plastics (SUPs) in life science laboratories account for approximately 5.5 million tonnes of waste per year globally. Of SUPs used in life science laboratories, Petri dishes, centrifuge tubes, and inoculation loops are some of the most common. In order to reduce the reliance on petrochemical-based SUPs in the life science research laboratory and minimize the negative environmental impacts associated with SUPs, this research investigates the applicability of polylactic acid (PLA) in single-use labware as a replacement for petrochemical-based plastics. PLA is one of the most well-studied biodegradable plastics that can be produced from sustainable resources. Commercially available PLA was used to 3D print a select range of labware to test the suitability of PLA-based material for routine microbiology work. An injection moulded PLA-based Petri dish was also designed and produced, for increased optical clarity. The biocompatibility was tested against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus epidermidis) strains of bacteria. The PLA-based labware did not negatively impact the cell growth, viability, and metabolic activity of the bacterial cultures. The injection moulded PLA Petri dish showed a reduced colony forming unit count for the Gram-negative E. coli strain compared to the polystyrene Petri dish, ∼1.5 × 109 CFU/mL and ∼3.0 × 109 CFU/mL respectively, during late-exponential growth. The colony counts were, however, in the same order of magnitude. This observed difference may be due to the internal environment inside the Petri dish, hence the internal O2 concentration, humidity, and temperature during bacterial growth were investigated. This work demonstrates, for the first time, a full successful workflow of bacterial growth using a sustainable bioplastic, providing a pathway to reducing the environmental impacts of SUPs in life science laboratories.

The Impact of an Extended Bleed-to-evisceration Interval on the Microbiological Quality of On-farm Slaughtered Cattle Carcasses

The uncertainties surrounding the microbiological risks of an extended exsanguination-to-evisceration interval have limited the implementation of on-farm slaughter in Europe. On-farm slaughter is increasingly advocated by farmers, consumers, and policymakers as a humane alternative to traditional slaughterhouse operations. However, concerns about hygiene and food safety, particularly bacterial contamination, have led to stringent time limits imposed by Member States on the interval between bleeding and evisceration. Microbiological standards for bovine carcasses in the European Union are governed by Commission Regulation (EC) No 2073/2005, which sets process hygiene criteria for aerobic colony count and Enterobacteriaceae. To investigate whether extending the bleed-to-evisceration interval compromises meat safety, five Holstein dairy cattle were slaughtered on-farm, with samples collected from the internal paralumbar area in contact with the intestines for up to four hours postmortem. The samples were analyzed for Enterobacteriaceae, aerobic colony count, and Escherichia coli. None of the samples exceeded the established thresholds of 1.5 and 3.5 log CFU/cm2 for aerobic colony count and Enterobacteriaceae, respectively, as defined by Belgian health authorities for the nondestructive sampling method. These preliminary findings suggest that on-farm slaughter with evisceration occurring up to four hours postmortem does not pose increased microbiological risks to human health. However, further research is necessary, particularly under warmer environmental conditions and with a larger sample size, to confirm these results and to explore additional factors that may influence bacterial translocation and digestive tract wall integrity.

Dynamic evolution of volatile compounds during cold storage of sturgeon fillets analyzed by gas chromatography-ion mobility spectrometry and chemometric methods

This study investigated the changes in quality and volatile flavoring compounds in sturgeon fillets during refrigeration. Potential flavor compounds were identified using orthogonal partial least squares discriminant analysis (OPLS-DA) and gas chromatography–mass spectrometry (GC-IMS). The results showed that TVB-N content, TBARS values, total colony counts, and K-value increased with prolonged refrigeration, reaching spoilage thresholds after approximately eight days. A total of 33 volatile compounds (including monomers and dimers) were detected in sturgeon fillets during different refrigeration periods, including aldehydes, alcohols, ketones, acids, esters, ethers, and other compounds. OPLS-DA further revealed flavor differences in sturgeon fillets across different refrigeration stages, identifying 18 distinct volatile compounds. Correlation analysis showed that trans-2-Pentenal, 2-methylpropanal, and glutaraldehyde were associated with pleasant odor to the frozen sturgeon fillets in the early stage, while hexane nitrile and thiazole were the main substances that caused unpleasant odors.

The mechanism of L1 cell adhesion molecule interacting with protein tyrosine kinase 2 to regulate the focal adhesion kinase–growth factor receptor-bound protein 2–son of sevenless–rat sarcoma pathway in the identification and treatment of type I high-risk endometrial cancer

Objective: The objective of this study was to investigate how L1 cell adhesion molecule (L1CAM) interacting with protein tyrosine kinase 2 (PTK2) affects endometrial cancer (EC) progression and determine its association with the focal adhesion kinase (FAK)–growth factor receptor-bound protein 2 (GRB2)–son of sevenless (SOS)–rat sarcoma (RAS) pathway. EC is a female cancer of major concern in the world, and its incidence has increased rapidly in recent years. L1CAM is considered a reliable marker of poor prognosis in patients with EC. Material and Methods: A single-center and prospective study was conducted using data from the Cancer Genome Atlas and samples from normal and EC tissues to explore the differential expression of L1CAM. Additional experimental models included human immortalized endometrial epithelium cells (hEECs) and EC cell lines such as KLE, RL95-2, and Ishikawa. L1CAM expression was regulated using lentiviruses designed for either overexpression or interference, and PTK2/focal adhesion kinase (FAK) signaling was inhibited with PF431396. Transfected KLE cells were injected into mice, and tumor growth was monitored over 14 days. Cellular proliferation and survival were assessed using cell counting kit, colony formation, and terminal deoxynucleotidyl transferase-mediated 2’-deoxyuridine 5’-triphosphate (dUTP) nick-end labeling assays. Metastatic behavior was evaluated through Transwell assays for cell migration and invasion. The expression levels of matrix metallopeptidase (MMP) 2 and MMP9 were determined by Western blot. In addition, the activation of the FAK–GRB2–SOS–RAS pathway was examined by assessing the protein levels of FAK, GRB2, SOS, and RAS. Results: There was a significant difference in L1CAM expression between EC tumor tissues and normal tissues, and L1CAM messenger RNA (1.85-fold) and L1CAM protein (2.59-fold) were significantly more expressed in EC tissues (P < 0.01) than in normal tissues. The tumor growth of L1CAM overexpressing EC cells was faster than that of negative control EC cells (6.43 fold; P < 0.001). L1CAM promoted the expression of FAK (1.43-2.72-fold; P < 0.001); enhanced EC cell proliferation (P < 0.01), survival and motility (P < 0.001), migration (P < 0.001), and invasion (P < 0.001); and activated the FAK–GRB2–SOS–RAS pathway, all of which were reversed when FAK expression was not upregulated (P < 0.001). Conclusion: By upregulating PTK2 and its encoded protein FAK, L1CAM was found to promote tumor progression and increase the activation of the FAK–GRB2–SOS–RAS pathway. These findings establish L1CAM and PTK2 as reference genes for poor prognostic prediction in EC and as targets for EC therapy, providing a valuable basis for distinguishing between benign and malignant endometrial conditions and justifying the necessity of targeted therapeutic approaches.

Assessment of microbial contamination in various processing rooms using culture-dependent and 16S rRNA methods in a commercial kitchen in eastern China

Commercial kitchens, frequently implicated in foodborne illness outbreaks, underscore the importance of studying bacterial communities in these settings. This study analyzed bacterial communities of two cooked food samples and 49 food contact surface samples in a commercial kitchen in eastern China, utilizing traditional bacterial cultivation methods and 16S rRNA sequencing. The cutting room exhibited the highest microbial contamination, with elevated bacterial colony counts on cutting boards and containers, suggesting it as the primary site for potential cross-contamination risks between different foods. Regarding bacterial communities, Coliform levels in refrigerators ranged from 1.0 to 3.0 log10 CFU/cm2, which is below sanitary standards. However, E. coli levels on food contact surfaces and cooked foods exceeded microbial limits set by GB1903 and GB 2726 in China. Proteobacteria were predominant at the phylum level across processing rooms, with Moraxellaceae notably prevalent and Pseudomonadaceae dominant in cooked foods at the family level. Source tracking identified food contact surfaces, including countertops, containers in the cutting room, and refrigerators in the cooking room, as primary sources of bacterial contamination in the final cooked foods, contributing 61.62% of contamination. These findings suggest that effective measures should be developed to control bacterial contamination on kitchen food contact surfaces to prevent cross-contamination among different cooked foods.

Effects of Metribuzin on Soil Microbiome and Weed Management Under Varying Planting Practices and Potato Seed Dormancy

AbstractWeed infestation in potato field has become a major concern to smallholder farmers and environment, requiring sustainable intervention. This study aimed to determine (i) whether metribuzin application rate (0, 0.5, 1 (standard), 1.5, and 2 kg ai ha−1) has effects on soil microbes and soil nutrients in the short term using potted soil and (ii) the influence of potato seed dormancy (short; Shangi variety and long; Unica variety) and planting technique (surface, ridge, or furrow planting) on the efficacy of weed management practice (metribuzin (480 g L−1) herbicide and hoeing) in the field. Bacterial colony counts were recorded upon isolation from the potted soil. Soil nutrients were also analysed before and after metribuzin treatment. Data on crop growth (height and stem count), weed abundance, yield, costs, and revenues were recorded from a field experiment. Morphologically distinct bacterial strains were tested for Gram reaction and response to carbon utilization using analytical profile index kits (API 50 CH and 20 NE). In total, nine distinct bacterial strains were isolated and all were Gram positive, with variation in response to carbon substrates. Concentration of 2.0 kg a.i ha−1 significantly (p ≤ 0.05) reduced bacterial count in the first day, followed by an increase in the subsequent incubation days, while 1.0 and 1.5 kg a.i ha−1 concentrations had the highest colony development index and species richness. Significant effects of metribuzin on soil pH, total N, and total organic C in the short term were revealed. Notably, weedy plots had the highest Shannon weed index. Weeds reduced stem count and height growth by 57% and 62% respectively. Plots with Shangi had 9.8% lower weed count than those with Unica and hence higher yield was recorded from the former. While surface planting had the lowest weed control efficacy, crop growth attributes, and yield, furrow and ridge planting were not significantly different. Weed abundance and crop growth attributes in metribuzin and hand-hoed plots did not differ significantly, yet hoeing resulted in 5.30 t ha−1 above that obtained from plots managed using metribuzin. Higher dry matter and tuber yield were observed from hoed plots with Shangi planted in furrow or ridge. Use of metribuzin resulted in higher net benefit ratio and marginal rate of return than hand hoeing. The results reveal that use of metribuzin early and later in the potato growing phase can minimize weed infestation, but the efficacy depends on planting method and seed dormancy.

Risk investigation and diversity of microbial contamination during slaughter processing of yellow-feathered broiler

The cleanliness of slaughter process is very pivotal to ensure the safety of broiler products, and slaughter process is prone to cause microbial contamination since it involves a highly collaborative system including different operations. The procedures in slaughter processing are primary sources of bacterial contamination, and it is crucial for poultry industry to maximize product safety and quality by understanding the connection between bacterial diversity on chicken carcasses. The commercial yellow-feathered broiler plant was investigated to analysis the risk of microbial contamination. In this study, 16S rRNA sequencing was used to evaluate microbial diversity and microbial contamination was investigated by collecting 910 samples from different processing steps. Generally, total count of bacteria colonies ranged from 3.14 log CFU/cm2 to 5.68 log CFU/cm2, and the microbial load at yellow-feathered broiler carcass samples was significantly higher than that at environmental samples; moreover, the cutting areas were the high-risk areas of cross-contamination. In addition, the relative abundance of Actinobacteria (9.61%) at water samples was significantly higher than that at contact surfaces samples. This paper provides a valuable theoretical insight into the diversity and changes in the bacterial community during slaughter beneficial for enterprise managers further enhancing yellow-feathered chicken quality.

INFLUENCE OF DISINFECTANTS ON THE TOTAL BACTERIAL CONTAMINATION OF DUCK EGGSHELLS

The role of the total viable microbial count on eggshells is of significant interest, as it relates to egg safety and product shelf life.The aim of this study was to assess the influence of various disinfectants on the overall bacterial contamination of duck eggshells. For this purpose, fresh high-quality duck eggs were obtained from a farm, and solutions of disinfectants were prepared: 6% hydrogen peroxide, 4% calcium hydroxide, 4% sodium carbonate, and 3% acetic acid. When disinfecting duck or goose eggs, the dosage of substances is doubled compared to chicken eggs. The eggs were treated with prepared disinfectant solutions, with varying exposure times. The exposure times for hydrogen peroxide were 4 and 8 minutes, for calcium hypochlorite – 2 and 5 minutes, for sodium carbonate – 10 and 30 minutes, and for acetic acid – 5 and 15 minutes. Samples of washings from the eggshells were collected both before and after disinfection. Dilutions were prepared and subsequently plated on Petri dishes with non-selective media, followed by incubation at 30°C for 72 hours. As a result of colony counting, the number of mesophilic aerobic and facultatively anaerobic microorganisms (CFU/egg) was determined.The results of the study showed a direct correlation between the inactivation of microorganisms and exposure time when using acetic acid, hydrogen peroxide, and calcium hypochlorite. A longer contact period of the eggs with sodium carbonate did not result in a measurable reduction in the number of viable microorganisms. It was also found that 4% calcium hypochlorite could completely inactivate microbes on the eggshell within 5 minutes. With a 2-minute exposure, the total microbial contamination was 9.2*10¹±0.7 CFU/egg.Thus, in this study, solutions of calcium hypochlorite, hydrogen peroxide, and acetic acid demonstrated high bactericidal properties and can be considered effective agents for disinfecting duck eggshells.Most scientific articles are devoted to the study of chicken eggs. In this work, the object of research is duck eggs, the best disinfectants for processing eggshells have been identified, which is an urgent task in poultry farming.The obtained results can help farmers implement more effective strategies for combating foodborne infections.

The Evaluation of 660, 810, and 940nm Laser Wavelengths on Nystatin-Resistant Candida albicans: An In-Vitro Study

Background: Candida albicans is the primary pathogen responsible for oral candidiasis. The emerging resistance of fungi to antifungal agents has led to the development of new fungicidal treatments. Objectives: This study aimed to analyze the effects of 660, 810, and 940 nm laser wavelengths on nystatin-resistant C. albicans. Methods: In this in vitro study, a standard strain of C. albicans and eight nystatin-resistant isolates were irradiated with 660, 810, and 940 nm diode lasers for 40 and 80 seconds (s) and compared with nystatin. Colony numbers and nystatin susceptibility were evaluated using the minimum inhibitory concentration (MIC). Results: All laser wavelengths significantly decreased the colony count of the standard strain of C. albicans, with 40s of 810 nm laser irradiation causing the maximum reduction in colony count (P810 nm < 0.001). Similarly, all laser wavelengths significantly reduced the colony count of nystatin-resistant isolates, and they were more effective than nystatin (unlike with the standard strain) (P < 0.05). The 810 nm laser irradiation for 40s demonstrated the greatest effect on MIC among the laser groups. Conclusions: The 810 nm laser for 40s was the most effective in reducing the colony count of nystatin-resistant C. albicans, and it eliminated resistance in all clinical isolates.

Effects of Platycodon grandiflorus on doxorubicin resistance and epithelial-mesenchymal transition of breast cancer cells via the p38 mitogen-activated protein kinase pathway.

With the increase of chemotherapy frequency for breast cancer, the drug resistance rate of patients is rising, accompanied by cell invasion and metastasis, thus causing mortality. We aimed to explore the mechanism by which Platycodon grandiflorus affects breast cancer cells in terms of the doxorubicin (Dox) resistance and epithelial-mesenchymal transition (EMT) via the p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway. MCF-7/R cell lines with resistance to Dox were established. After 24h of culture with DMEM (blank group), they were divided into Platycodon grandiflorus, Platycodon grandiflorus + Ophiopogon japonicus, Platycodon grandiflorus + Curcumae Rhizoma, Platycodon grandiflorus + Curcumae Rhizoma + U46619 groups. Flow cytometry, colony formation assay, as well as Transwell assay were performed to examine the cells for apoptosis, proliferation, and invasion, respectively. Western blotting was performed to measure the phosphorylated (p)-p38 MAPK-to-p38 MAPK ratio together with N-cadherin, vimentin, β-catenin, and E-cadherin protein expressions. Compared with the blank group, the half maximal inhibitory concentration (IC50), number of cell colonies, number of invading cells and expressions of proteins related to EMT (i.e. N-cadherin, vimentin, and β-catenin) significantly reduced, but increases in apoptosis rate, p-p38 MAPK/p38 MAPK ratio and E-cadherin protein expression were observed in different groups (P < 0.05). Compared with the Platycodon grandiflorus + Curcumae Rhizoma group, the Platycodon grandiflorus + Curcumae Rhizoma + U46619 group had significantly decreased IC50, cell colony count, invading cell count and β-catenin, N-cadherin, and vimentin expressions, in addition to elevated E-cadherin protein expression, apoptosis rate, and p-p38 MAPK/p38 MAPK ratio (P < 0.05). Platycodon grandiflorus can reverse the resistance of breast cancer cells to Dox and regulate their biological activities by activating the p38 MAPK signaling pathway.

Effect of zinc oxide-eugenol endodontic paste on planktonic aggregates and biofilm of Enterococcus faecalis - An atomic force microscopy evaluation

ObjectiveThis work aimed to evaluate the in vitro effect of zinc oxide-eugenol paste (ZOE) on planktonic aggregates (EfPA) and biofilm (EfBio) of Enterococcus faecalis, focusing on their morphological aspects observed and analyzed using atomic force microscopy (AFM). DesignThe eugenol and paste were characterized by Gas Chromatography coupled with Mass Spectrometry (GC-MS) and Fourier Transform Infrared Spectroscopy (FTIR), respectively. The effect of ZOE on EfPA and EfBio was evaluated by a direct-contact test through colony counting and crystal violet staining protocol. AFM images of untreated and treated EfPA and EfBio growth on bovine dentin were obtained to analyze the morphological damage caused by the treatments. ResultsThe characterization showed high purity in the eugenol composition and chemical interaction between the components of the paste. A bactericidal effect on aggregates was observed after 6 h of exposure, and on biofilm after 24 h of treatment (p < 0.001). A disruptive effect on the biofilm was also evident. AFM images revealed the formation of EfPA, with a notable presence of an exopolysaccharide matrix. After 6 h of ZOE treatment, there was a significant increase in the size and surface roughness profile of treated cells (p < 0.05). Loss of typical cell morphology was observed after 24 h. The effect on the biofilm showed a tendency towards a less condensed biofilm pattern in the treated group, with no differences in surface roughness. ConclusionZOE presents bactericidal action on EfPA and EfBio, promoting significant morphological changes after treatment, especially in the aggregates.

Synthesis and antibacterial activity of silver doped zinc sulfide/chitosan bionanocomposites: A new frontier in biomedical applications

Numerous microbial species have caused infectious diseases worldwide, which have become a social burden and a menace to the community. So, there is a need to develop antimicrobial materials and specialized materials for biomedical applications. In the present investigation, we report the simple synthesis, the physicochemical, and antibacterial activity of Silver doped zinc sulfide (ZnS: Ag) capped with Chitosan (CS) to produce ZnS: Ag/CS bionanocomposites (BNCs). The prepared BNCs was evaluated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and UV–Vis spectroscopy. According to the XRD results, ZnS: Ag/CS particles with semicrystalline chitosan/hexagonal ZnS phase structures and an average crystallite size in the range of 30–40 nm was formed. According to FESEM images, a spherical/hexagonal shape of ZnS: Ag particles embedded in the polymeric chitosan matrix. The colony counting method was employed to investigate the antibacterial activity on Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. The results revealed that ZnS: Ag particles and ZnS: Ag/CS BNCs have stronger antibacterial activities than pure CS and ZnS. The reduction percentage of ZnS: Ag/CS BNCs against S. aureus and E. coli after 6 h of treatment was >99.9 % and 70 % respectively. These findings suggest that ZnS: Ag/CS BCs not only offer superior antimicrobial properties compared to individual ZnS and CS but also have great potential for advancing biomedical applications due to their enhanced antibacterial performance. The simplicity of the synthesis method and the use of non-toxic materials like chitosan make this a sustainable approach for developing antimicrobial agents, which is a key advantage of this study.