Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major pathogens associated with life-threatening infections, showing resistance to various antibiotics. This study aimed to assess the influence of monolaurin on biofilm-forming MRSA.
Methods: The agar dilution method determined the minimum inhibitory concentration (MIC) of monolaurin against MRSA isolates and explored its impact on the resistance profile of selected antibiotics. The assessment of combined therapy involving monolaurin and antibiotics was conducted using fractional inhibitory concentration (FIC). The tissue culture plate strategy appraised monolaurin's antibiofilm activity and its inhibitory concentration (IC50), with assessment via scanning electron microscopy. Reverse transcription polymerase chain reaction (RT-PCR) discerned a monolaurin effect on the expression of the icaD gene.
Results: Monolaurin exhibited MIC values ranging from 500 to 2000 μg/mL. FIC index showed a synergistic effect of monolaurin with β-lactam antibiotics ranging from 0.0039 to 0.25 (p < 0.001). Among the 103 investigated MRSA isolates, 44 (44.7%) displayed moderate biofilm formation, while 59 (55.3%) were strong biofilm producers. Antibiofilm activity demonstrated concentration dependence, confirming monolaurin's capacity to inhibit biofilm formation and exhibited strong eradicating effects against preformed MRSA biofilms with IC50 values of 203.6 μg/mL and 379.3 μg/mL, respectively. Scanning electron microscope analysis revealed reduced cell attachments and diminished biofilm formation compared to the control. The expression levels of the icaD gene were remarkably reduced at monolaurin concentrations of 250 and 500 μg/mL.
Conclusion: Monolaurin had significant inhibitory effects on MRSA pre-existing biofilms as well as biofilm development. So, it can be employed in the treatment of severe infections, particularly those associated with biofilm formation including catheter-associated infections.
The escalating antibiotic resistance rates in Neisseria gonorrhoeae (N. gonorrhoeae) are now a grave concern. There is a critical need for alternative treatment options for infection since N. gonorrhoeae has developed resistance to multiple antibiotics used for treatment. In this study, plant nanoemulsions from Ocimum tenuiflorum, Moringa oleifera, and Azadirachta indica were tested for their antimicrobial properties against N. gonorrhoeae. The study also assessed the toxicity of these plant nanoemulsions using human erythrocytes. The plants were sourced from the Botanical Gardens in Durban, South Africa. Nanoemulsions were produced from the dried plants using established methods. The nanoemulsion-based plant extracts were tested against laboratory (World Health Organization (WHO) strains) and clinical isolates of N. gonorrhoeae using the disk diffusion method. All six isolates had zones of inhibition for the 1000 μM concentration for all three nanoemulsion-based plant extracts. No zones of inhibition were observed for 100 μM, 10 μM, and 1 μM nanoemulsion concentrations for five of the isolates. Isolate G176 had zones of inhibition at 1000 μM and 100 μM concentrations for the nanoemulsions of Ocimum tenuiflorum. Both the WHO strains had zones of inhibition appearing at the 1000 μM concentration. For the WHO Y strain, zones of inhibition for both 1000 μM and 100 μM concentrations were observed for the nanoemulsions of Ocimum tenuiflorum and Azadirachta indica. According to the analysis, there was 0% haemolytic activity observed which suggests the nontoxic nature of the extracts. This study showed that the nanoemulsion and plant mix may potentially be used as a safer alternative to treat gonorrhoea.
The goal of the study is to evaluate metabolic and morphological changes of the facultative alkaliphile Bacillus aequororis 5-DB and the weakly alkali-resistant B. subtilis ATCC 6633 in a wide pH range and at different NaCl concentrations. The alkaliphile B. aequororis 5-DB is shown to have a broader general resistance to adverse factors (wide pH range, 50 g/L NaCl) than a weakly alkali-tolerant strain of the same genus. This alkaliphile is also shown to have a significantly greater resistance not only to high pH but also to low pH in comparison with B. subtilis ATCC 6633. The resistance of B. aequororis 5-DB to low pH was expressed in higher metabolic activity, maintenance of ΔpH, and no significant cell damage. The selected set of methods (reduction of resazurin to resorufin by cell dehydrogenases, bioluminescent method for determining ATP, AFM, and measurement of intracellular pH) allows us to adequately assess the ability of microbial cells to withstand harsh environmental factors. Nonspecific resistance of B. aequororis 5-DB was proven using a complex of selected methods. Tolerance to a wide range of pH and high salt concentrations may be useful for biotechnological applications of the strain.
Cellulolytic microorganisms secrete cellulase, which plays a crucial role in the conversion of lignocellulosic biomass into value-added products with diverse applications in industries, such as biofuel, healthcare, and agriculture. As the world transitions to a bioenergy future, cellulase demand is likely to expand. However, the high cost and low catalytic activity of cellulase hinder the commercialization of biorefineries. Searching for cellulase-producing microorganisms in different environments through bioprospecting can aid in broadening the range of cellulases that are currently available. Meanwhile, the cellulolytic activity of marine microorganisms remains largely unexplored, making it difficult to compare the cellulolytic activity of terrestrial and marine environments. Thus, this study aimed to investigate the diversity and activity of culturable cellulolytic microorganisms in four terrestrial and three marine sites within Panay Island, Philippines. The results showed that the cellulolytic microbial load was tenfold higher in the terrestrial sites than in the marine sites, possibly due to the dynamic mangrove environment. Out of the 42 isolates with a high cellulolytic index (CI) of ≥3.0, 36 were from terrestrial and 6 from marine habitats. The CMCase, Avicelase, and FPase activities were then tested on the 18 isolates with the highest CI. It was observed that many isolates had a high CI, but few exhibited high enzyme activities. Marine isolates showed higher CMCase and Avicelase activities, with comparable FPase activity to their terrestrial counterparts. Isolates S1ACP6B from a sugarcane field and MS1OMP2A from a mangrove site exhibited the highest cellulase activities at 0.41 and 0.29 U/mg, respectively, and were identified as Enterobacter roggenkampii and Rhodococcus erythropolis, respectively. Among the 18 identified isolates, three are resistant to chloramphenicol and three isolates are potentially new species of Halomonas sp. MS1ACP1B, Albirhodobacter sp. MP2ACP3B, and Saccharomycetaceae sp. B1CZP10A. Overall, this study provides an insight on the composition of cellulolytic microbial load and their activities among various habitats.
The fungus Phyllosticta citricarpa is a quarantine phytopathogen responsible for causing citrus black spot (CBS) disease. To export fruits to CBS-free countries, they must undergo a sanitation process to ensure disease control. In this study, neem essential oil (NEO) was tested against P. citricarpa for the first time as an alternative sanitizer. In vitro experiments were conducted to determine the inhibition concentration of NEO for P. citricarpa, and the mode of action of the essential oil was evaluated. In vivo assays were performed to simulate the sanitization process used in packinghouses. NEO was characterized by GC-MS/MS. The results revealed that NEO at 100 μL·mL-1 exhibited a similar inhibitory effect as copper oxychloride, suppressing 89.68 ± 1.14% of fungal mycelium growth. Fluorescence microscopy experiments demonstrated that NEO functions by disrupting the cytoplasmic membrane of fungal hyphae, leading to their death within 30 minutes of contact with NEO. GC-MS/MS characterization revealed a high presence of phenolic compounds, which serve as the primary antifungal agents responsible for the action against fungal hyphae. In vivo assays showed that NEO at 100 μL·mL-1 also reduced microorganisms (CFU mL-1) by 93.00 ± 3.88% compared to the negative control. Overall, the results demonstrate that NEO can effectively serve as an alternative sanitizer against P. citricarpa in citrus packinghouses. Our findings allow future studies to explore the use of NEO for sanitizing other fruits and combating different phytopathogens to broaden its potential application in fruit sanitation for export.
Background: Type 2 diabetes is a condition in which the body becomes resistant to the effects of insulin, leading to reduced insulin production in the pancreas. It has genetic- and family-related risk factors that cannot be changed, along with modifiable lifestyle factors. The precise genetic causes of type 2 diabetes are still unknown. However, individuals can potentially slow or stop the progression of the condition by making dietary adjustments and increasing physical activity levels. Material and Methods. Forty-five type II diabetic patients in the study included participants between 40 and 60 years old, with a minimum duration of one year, as well as 45 healthy control subjects who were matched in terms of age and sex, and had no underlying systemic diseases. Oral examination is done for the symptoms including burning sensation, candidiasis, and a reduction in the production of saliva. The rate of saliva flow (in milliliters per minute) was measured in samples of saliva that were not stimulated. The salivary trace elements and levels of adipocytokines were evaluated using colorimetric and Ethylenediaminetetraacetic acid (ELISA) testing. The quantification of Candida colony numbers, an enrichment and culture approach, was used to achieve a concentration of 100,000 colony-forming units per milliliter (CFU/ml). The ShowNovo WG1 halimeter was used to measure volatile sulfur compounds in breath. The salivary glucose oxidase assay was conducted using a colorimetric technique, while the determination of trace elements was also performed using a colorimetric assay method.
Result: The diabetic group exhibited a significant increase in the number of Candida spp colonies due to elevated levels of glucose in the saliva (p > 0.05). However, the variables being examined, such as body mass index (BMI), burning mouth syndrome (BMS), salivary flow rate (SFR), salivary leptin, salivary copper, and salivary magnesium, did not exhibit any significant variations in quantities between the diabetic and healthy groups (p > 0.05).
Conclusion: The data collected in this research aid in the creation of a preventative program for oral fungal infections in individuals with type 2 diabetes. The program utilizes saliva and its constituents.
Background: Bacterial bloodstream infections (BSIs) are the leading cause of sepsis-related morbidity and mortality worldwide. The emergence and spread of antimicrobial resistance (AMR) in bacteria is also a growing global concern. As a result, data on bacterial profile and their antibiogram are essential for strategies to contain drug resistance, improve the quality of patient care, and strengthen health systems.
Methods: Retrospective data from bacteriological results of blood samples of BSI-suspected patients from 2018 to 2021 were collected using a data collection sheet. Standard bacteriological techniques were followed during sample collection, culture preparation, bacterial identification, and antibiotic susceptibility testing (AST). We used Epi Info version 7 to enter and clean the data and then exported it to SPSS version 26 for analysis. Logistic regression models were used to measure the association between variables. A p value <0.05 with a 95% confidence interval was considered as statistically significant.
Result: Of the total 2,795 blood culture records, 455 (16.3%) were culture positive for bacteria, with Klebsiella pneumoniae (26%) and Staphylococcus aureus (24.6%) being the leading isolates. The isolates were highly resistant to common antibiotics, with more than 80% of them being resistant to ceftriaxone and penicillin. Moreover, about 43% of isolates were multidrug resistant (MDR), with Klebsiella pneumoniae (65.5%), Acinetobacter species (56.7%), and Citrobacter species (53.8%) being the most common MDR isolates. Age and diagnosis year were significantly associated with the presence of bacterial BSIs (p value <0.05).
Conclusion: Bacterial BSI and AMR were growing concerns in the study area. Bacteremia was more common in children under the age of five, and it decreased as the patient's age increased. The alarming rate of AMR, such as MDR blood isolates, calls for periodic and continuous monitoring of antibiotic usage in the study area.
Pseudomonas aeruginosa is an opportunistic pathogen in HAIs with two facets: the most studied is the high rate of antimicrobial resistance, and the less explored is the long list of virulence factors it possesses. This study aimed to characterize the virulence genes carried by strains as well as the profile of cytokines related to inflammation, according to the resistance profile presented. This study aims to identify the virulence factors associated with MDR strains, particularly those resistant to carbapenems, and assess whether there is a cytokine profile that correlates with these characteristics. As methodology species were identified by classical microbiological techniques and confirmed by molecular biology, resistance levels were determined by the minimum inhibitory concentration and identification of MDR strains. Virulence factor genotyping was performed using PCR. In addition, biofilm production was assessed using crystal violet staining. Finally, the strains were cocultured with PBMC, and cell survival and the cytokines IL-1β, IL-6, IL-10, IL-8, and TNF-α were quantified using flow cytometry. Bacteremia and nosocomial pneumonia in adults are the most frequent types of infection. In the toxigenic aspect, genes corresponding to the type III secretion system were present in at least 50% of cases. In addition, PBMC exposed to strains of four different categories according to their resistance and toxicity showed a differential pattern of cytokine expression, a decrease in IL-10, IL-6, and IL-8, and an over-secretion of IL-1b. In conclusion, the virulence genes showed a differentiated appearance for the two most aggressive exotoxins of T3SS (exoU and exoS) in multidrug-resistant strains. Moreover, the cytokine profile displays a low expression of cytokines with anti-inflammatory and proinflammatory effects in strains carrying the exoU gene.
The common bean (Phaseolus vulgaris L.) is a yearly herbaceous plant grown for its edible dry seeds. Despite that, pests and diseases have contributed to the decline of common bean production in Kenya. Therefore, the study aimed to identify bacteria from Lake Bogoria, assess the pathogenicity of Rhizoctonia solani Kühn, screen for effective antifungal agents, and determine secondary metabolites for the biocontrol of R. solani. A total of 49 bacteria were isolated, of which 10 isolates had varied mycelial inhibition rates of R. solani in the co-culture technique. The efficacy of volatile compounds of the three selected bacterial strains had varied mycelial growth and percent reduction against R. solani. The pathogenicity assay showed varied plant parameters and biomass of R. solani on common bean plantlets. The molecular characterization based on 16 S ribosomal RNA confirmed the selected bacterial strains' identity with a diversity similar to the Bacillus genus. Gas chromatography-mass spectrometry analysis of secondary metabolites showed different antimicrobial compounds produced by Bacillus subtilis strain TW21. In conclusion, Lake Bogoria harbors useful microbes as biocontrol agents against plant pathogens. The current study discovers the potential biocontrol bacteria isolates from Lake Bogoria as alternative bioagents against R. solani. Therefore, the isolate Bacillus subtilis strain TW21 can be assessed further for toxicological and ecotoxicological studies and registered by the Pest Control Products Board (PCPB), Kenya, as a biocontrol product against common diseases affecting common beans' production.
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