Microbiology Research

31 pages, 5412 KiB

Open AccessReview

Tick-Borne Encephalitis Virus (TBEV): Epidemiology, Diagnosis, Therapeutic Approaches and Some Molecular Aspects—An Updated Review

by Valentina Mittova, Zurab R. Tsetskhladze, Catherine Motsonelidze, Rosanna Palumbo, Caterina Vicidomini and Giovanni N. Roviello

Microbiol. Res. 2024, 15(4), 2619-2649; https://doi.org/10.3390/microbiolres15040174 - 10 Dec 2024

Abstract

Tick-borne encephalitis virus (TBEV) is a significant public health concern, particularly in rural regions, like the Caucasus, where tick-borne diseases are prevalent. The review contains comprehensive data on TBEV circulation in the Caucasus region, demonstrating TBE cases in the North Caucasus and Georgia, [...] Read more.

Tick-borne encephalitis virus (TBEV) is a significant public health concern, particularly in rural regions, like the Caucasus, where tick-borne diseases are prevalent. The review contains comprehensive data on TBEV circulation in the Caucasus region, demonstrating TBE cases in the North Caucasus and Georgia, as well as the identification of new endemic foci in Armenia and Azerbaijan, highlighting the need for further epidemiological studies and surveillance in the region. This review provides an updated overview of TBEV, encompassing its status, subtypes, life cycle and circulation in nature, epidemiology, new approaches to TBE treatment and diagnostics, and recent insights into molecular aspects. Understanding the complexities of TBEV transmission, clinical manifestations, and advancements in diagnostic techniques is crucial for effective management and control strategies. Furthermore, exploring the molecular mechanisms underlying TBEV pathogenesis and host interactions can offer valuable insights for developing novel therapeutics and preventive measures. This comprehensive review aims to consolidate recent research findings and enhance our understanding of TBEV, ultimately contributing to improved public health interventions and patient outcomes. Full article

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12 pages, 1436 KiB

Open AccessArticle

Rhizobacterial Isolates from the Native Plant Ceanothus velutinus Promote Growth in Two Genotypes of Tall Fescue

by Ananta Raj Devkota, Sukhmanjot Kaur and Amita Kaundal

Microbiol. Res. 2024, 15(4), 2607-2618; https://doi.org/10.3390/microbiolres15040173 - 10 Dec 2024

Abstract

Global warming-induced climate change haunts the world, posing a critical threat to plant health and crop production. Overusing chemical fertilizers and pesticides poses a significant threat to soil health. Ceanothus velutinus (snowbrush) is a drought-tolerant, actinorhizal native plant found in the Intermountain West [...] Read more.

Global warming-induced climate change haunts the world, posing a critical threat to plant health and crop production. Overusing chemical fertilizers and pesticides poses a significant threat to soil health. Ceanothus velutinus (snowbrush) is a drought-tolerant, actinorhizal native plant found in the Intermountain West region of the US that harbors many plant growth-promoting rhizobacteria (PGPR). In this study, we evaluated the effects of PGPR CK-06, CK-22, CK-44, and CK-50 from C. velutinus on the growth and development of two tall fescue genotypes: (i) a lawn-type tall fescue blend and (ii) an endophyte-free forage-type tall fescue known as Armory. Tall fescue plants were grown in field soil and sand mix in pots and treated twice with 5 mL of bacterial inoculum. Two isolates, CK-06 and CK-22, significantly increased tiller numbers (p < 0.05) in the lawn-type tall fescue blend, and all isolates showed a significant increase in fresh and dry weight compared to the control. Isolate CK-22 significantly increased the tiller number and fresh and dry weight of the forage-type tall fescue Armory compared to the control. Isolates CK-44 and CK-50 tested positive for sulfur-oxidizing properties, and CK-44 was able to restore the sulfur content in sulfur-deficient soil compared to the control. Full article

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14 pages, 1335 KiB

Open AccessArticle

Analysis of Subtype, Molecular Clusters and Drug Resistance in Newly Diagnosed Individuals with HIV-1 Infection in Jiaxing City, Zhejiang Province, China in 2023

by Ganglin Ren, Xiaofei Zhang, Zhijian Ge, Yamei Zhou, Shencong Lv, Yin Song, Jimei Ji, Lina Li, Yong Yan and Guoying Zhu

Microbiol. Res. 2024, 15(4), 2593-2606; https://doi.org/10.3390/microbiolres15040172 - 10 Dec 2024

Abstract

The analysis of the molecular epidemiological characteristics of newly diagnosed HIV-infected patients in Jiaxing City is essential for developing effective HIV prevention. Blood samples were collected from newly diagnosed HIV-infected individuals in Jiaxing City from October 2022 to October 2023, and the HIV-1 [...] Read more.

The analysis of the molecular epidemiological characteristics of newly diagnosed HIV-infected patients in Jiaxing City is essential for developing effective HIV prevention. Blood samples were collected from newly diagnosed HIV-infected individuals in Jiaxing City from October 2022 to October 2023, and the HIV-1 pol region gene was amplified and sequenced. These sequences were used to construct a molecular transmission network and analyse transmitted drug resistance mutations. We identified 11 subtypes, of which CRF07_BC and CRF01_AE were the most prevalent. The rate of surveillance drug resistance mutation (SDRM) sites in newly diagnosed cases was 9%. A total of 37 molecular transmission clusters were identified, the largest of which was the CRF07_BC-1 cluster (13 nodes). This cluster has five probable high-risk transmitters. Two additional larger clusters in the molecular network were the heterosexual transmission clusters for middle-aged and older males, CRF08_BC-1 (eight nodes) and CRF85_BC-1 (eight nodes). The mean degree of the two clusters was high, and the patients were high-risk transmitters, indicating a higher risk of HIV transmission. The distribution of HIV-1 subtypes in Jiaxing City was widespread, with moderate levels of transmission resistance. Larger molecule clusters carry a high risk of transmission, indicating that we should strengthen monitoring and intervention. Full article

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18 pages, 1659 KiB

Open AccessArticle

Bioremediation of Oil-Contaminated Soils Using Biosurfactants Produced by Bacteria of the Genus Nocardiopsis sp.

by Liliya Biktasheva, Alexander Gordeev, Arina Usova, Anastasia Kirichenko, Polina Kuryntseva and Svetlana Selivanovskaya

Microbiol. Res. 2024, 15(4), 2575-2592; https://doi.org/10.3390/microbiolres15040171 - 9 Dec 2024

Abstract

One of the effective and safe methods of soil cleanup from oil pollution is bioremediation by introducing microorganisms or their metabolites. In this study, the effect of biosurfactants produced by Nocardiopsis sp. 3mo on the rate of bioremediation of oil-contaminated soils was assessed. [...] Read more.

One of the effective and safe methods of soil cleanup from oil pollution is bioremediation by introducing microorganisms or their metabolites. In this study, the effect of biosurfactants produced by Nocardiopsis sp. 3mo on the rate of bioremediation of oil-contaminated soils was assessed. Biosurfactants were introduced into soils contaminated with 2% oil at a concentration of 0.05 and 0.1%, and the degree of hydrocarbon degradation was estimated within 63 days. It was found that the studied biosurfactant belonged to the glycopeptide type. The aeration and irrigation of oil-contaminated soil (PSA) resulted in a 5% decrease in the number of hydrocarbons. The introduction of biosurfactants into oil-contaminated soil at a concentration of 0.5 (BS(0.5)) and 1 g kg⁻¹ (BS(1)) resulted in a 29 and 35% decrease in the content of hydrocarbons, respectively. The state of the soil microbiome was assessed by its metabolic activity. Thus, the respiratory activity of microorganisms on the first day after contamination increases by 5–7 times, and urease activity by 3–4 times. The introduction of oil into the soil during the first day reduces the activity of dehydrogenase by 2.3–1.6 times. In the process of bioremediation, the indicators of microbial activity returned to values close to the original. Thus, it was established that the use of biosurfactants produced by Nocardiopsis sp. 3mo increases the ability of the native soil community to degrade hydrocarbons. Full article

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21 pages, 2054 KiB

Open AccessReview

Bioinformatic Methodologies in Assessing Gut Microbiota

by James Douglas Fox, Austin Sims, Morgan Ross, Jeffery Bettag, Alexandra Wilder, Dylan Natrop, Alison Borsotti, Sree Kolli, Shaurya Mehta, Hema Verma, Kento Kurashima, Chandrashekhara Manithody, Arun Verma and Ajay Jain

Microbiol. Res. 2024, 15(4), 2554-2574; https://doi.org/10.3390/microbiolres15040170 - 3 Dec 2024

Abstract

Bioinformatic methodologies play a crucial role in the assessment of gut microbiota, offering advanced tools for analyzing complex microbial communities. These methodologies involve high-throughput sequencing technologies, such as 16S rRNA gene sequencing and metagenomics, which generate vast amounts of data on microbial diversity [...] Read more.

Bioinformatic methodologies play a crucial role in the assessment of gut microbiota, offering advanced tools for analyzing complex microbial communities. These methodologies involve high-throughput sequencing technologies, such as 16S rRNA gene sequencing and metagenomics, which generate vast amounts of data on microbial diversity and functional potential, as well as whole-genome sequencing, which, while being more costly, has a more expansive potential. Bioinformatics tools and algorithms process these data to identify microbial taxa and quantify and elucidate their roles within the microbiome. Advanced statistical and computational models further enable the identification of microbiota patterns associated with various diseases and health conditions. Overall, bioinformatic approaches are essential for deciphering the complexities of gut microbiota so that, in the future, we may be able to discover treatments and technologies aimed at restoring or optimizing the microbiome. The goal of this review is to describe the differences in methodology and utilization of 16S versus whole-genome sequencing to address the increased understanding of the role that the gut microbiome plays in human physiology and pathology. Full article

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19 pages, 2037 KiB

Open AccessArticle

Disruption of Biofilm Formation by Dead Sea Soil Extracts: A Novel Approach Against Diabetic Foot Wound Isolates

by Mohammad Zubair, Farha Fatima, Sumbul Rahman, Tariq Alrasheed, Roba Alatawy and M. Ahmed Mesaik

Microbiol. Res. 2024, 15(4), 2535-2553; https://doi.org/10.3390/microbiolres15040169 - 2 Dec 2024

Abstract

Bacterial biofilms are closely associated with the rising threat of antimicrobial resistance, which is becoming a global concern. Recently, there has been increased interest in natural extracts as potential antimicrobial agents. One such extract is Dead Sea mud. While there is some evidence [...] Read more.

Bacterial biofilms are closely associated with the rising threat of antimicrobial resistance, which is becoming a global concern. Recently, there has been increased interest in natural extracts as potential antimicrobial agents. One such extract is Dead Sea mud. While there is some evidence of its antimicrobial properties, it has not been extensively studied. Therefore, we designed a study to evaluate the potential of Dead Sea soil as an antimicrobial agent. For this purpose, three bacterial species (Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus) were isolated from the ulcerated foot of a patient in a hospital in Tabuk. P. aeruginosa exhibited significant antibiotic resistance, particularly to Levofloxacin (90%) and Tobramycin (80%), while S. aureus showed 70% resistance to Levofloxacin but no vancomycin resistance. Biofilm activity varied among bacterial strains, with P. aeruginosa showing 30% strong biofilm production. MIC values indicated resistance levels, with P. aeruginosa strain PA8 having the highest MIC at 650 µL/mL. All strains showed significant differences in exopolysaccharide (EPS) production at 0.25 × MIC (p ≤ 0.05) and 0.5 × MIC (p ≤ 0.005). Similarly, alginate production was significantly reduced at 0.25 × MIC (p ≤ 0.05), with even greater inhibition at 0.5 × MIC for combinations such as EC7 + SA5 (p ≤ 0.001). Hydrophobicity significantly changed at 0.25 × MIC (p ≤ 0.05), and combinations revealed highly significant reductions at 0.5 × MIC (p ≤ 0.001). Additionally, significant differences in outer membrane disruption were observed (p ≤ 0.05) with greater effects at 0.5 × MIC (p ≤ 0.005). Swarming motility was notably reduced for SA5 at 0.25 × MIC (p ≤ 0.05) and for PA2 at 0.5 × MIC (p ≤ 0.001). Chitinase activity showed greater reductions at 0.5 × MIC, with EC7 exhibiting the highest decrease. Lastly, sub-MIC concentrations enhanced reactive oxygen species (ROS) production, particularly for strains PA2 and SA5. Our results demonstrate the excellent potential of Dead Sea soil extract as an antimicrobial compound. Future studies should incorporate in vivo models to validate these findings clinically. Full article

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13 pages, 3846 KiB

Open AccessArticle

Paper Towel Method: In Vitro Inoculation Technique for Rapid and Robust Assessment of Clusterbean and Cowpea Genotypes Against Macrophomina phaseolina

by Krupal V. Prajapati, Mitesh R. Prajapati, B. Megala Devi, Jyotika Purohit, Bindu Panickar, Sivasudha Thilakar, Manoj Choudhary, A. Abdul Kader Jailani and Anirudha Chattopadhyay

Microbiol. Res. 2024, 15(4), 2522-2534; https://doi.org/10.3390/microbiolres15040168 - 2 Dec 2024

Abstract

The development and standardization of an effective inoculation technique are essential for reliable screening of crop genotypes. In this study, three inoculation methods—in vitro paper towel, in vitro agar, and soil inoculation in pots—were tested to evaluate the pathogenic potential of Macrophomina phaseolina [...] Read more.

The development and standardization of an effective inoculation technique are essential for reliable screening of crop genotypes. In this study, three inoculation methods—in vitro paper towel, in vitro agar, and soil inoculation in pots—were tested to evaluate the pathogenic potential of Macrophomina phaseolina, the causative agent of dry root rot (DRR). Since the pathogenicity of M. phaseolina is influenced by environmental factors, identifying a robust inoculation method is critical. Among the three techniques, the paper towel inoculation method resulted in the highest seedling mortality of 66.66% in cluster beans and 86.67% in cowpeas within just ten days, demonstrating its effectiveness. The agar inoculation technique, while successful, required 15 days to confirm pathogenicity, with seedling mortality rates of 63.33% for cowpeas and 53.33% for cluster beans. In contrast, the soil inoculation method showed comparatively lower mortality rates, with 36.66% for cluster beans and 26.67% for cowpeas. Based on these findings, the paper towel method emerged as the most efficient technique for inducing rapid pathogenicity in M. phaseolina in both cowpeas and cluster beans. Its suitability was further validated through the screening of released varieties of these crops compared against the soil inoculation method. Notably, genotypes that appeared moderately resistant under the soil inoculation method were found to range from susceptible to highly susceptible when evaluated using the paper towel technique. These results underscore the reliability of the paper towel method as a rapid and robust screening tool for identifying resistant genotypes of cowpea and cluster bean on a larger scale. Full article

(This article belongs to the Special Issue Antifungal Activities of Plant Extracts)

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15 pages, 2867 KiB

Open AccessArticle

Bacterial Microbiota of the Brown Dog Tick (Rhipicephalus sanguineus), a Broad Starting Point to Establish Potential Pathogens in Northern Mexico

by Cristina García-De la Peña, Annely Zamudio-López, Sergio I. Barraza-Guerrero, Ernesto Martínez-Aranda, Josué M. De la Cruz-Ramos, Anehlvy Acosta-Ayala, Quetzaly K. Siller-Rodríguez, María G. Torres-Delgado, Verónica Ávila-Rodríguez, Jesús Vásquez-Arroyo, Luis M. Valenzuela-Núñez and Juan Carlos Herrera-Salazar

Microbiol. Res. 2024, 15(4), 2507-2521; https://doi.org/10.3390/microbiolres15040167 - 30 Nov 2024

Abstract

Ticks are important vectors of pathogenic bacteria that cause diseases in both humans and animals. Analysis of tick microbiota via massive sequencing allows rapid and comprehensive identification of almost all bacteria inhabiting ticks. This has improved the detection of emerging pathogens and has [...] Read more.

Ticks are important vectors of pathogenic bacteria that cause diseases in both humans and animals. Analysis of tick microbiota via massive sequencing allows rapid and comprehensive identification of almost all bacteria inhabiting ticks. This has improved the detection of emerging pathogens and has helped define their relationship with public health. In Mexico, the brown dog tick (Rhipicephalus sanguineus sensu lato) is a public health problem, especially in northeast Durango. In the present study, the bacterial microbiota of this tick was determined using third-generation massive sequencing (PacBio, V1–V9 region of the 16S rRNA gene); bacteria with pathogenic potential that are transmitted by salivation and those that can be transmitted by accidental regurgitation of the parasite were also identified. In 2024, 60 dogs were searched for unfed ticks; then, 15 groups of female ticks and 15 groups of male ticks were formed, with each group consisting of 30 individuals. DNA was extracted from each tick pool, and the complete 16S rRNA gene was amplified (PacBio). Bioinformatics analysis was performed in QIIME2 (Quantitative Insights into Microbial Ecology) to obtain amplicon sequence variants (ASVs). Alpha and beta diversity metrics, as well as statistical analyses, were performed to test for differences between the microbiota of females and males. The bacterial taxa were classified into 21 phyla, 24 classes, 81 orders, 137 families, 339 genera, and 565 species. The male microbiota presented a significantly greater number of ASVs and a greater phylogenetic diversity index (FaithPD). Additionally, the unweighted UniFrac metric was significantly different between the sexes. The endosymbiont Coxiella mudrowiae was significantly more abundant in females, and Ehrlichia canis was more abundant in males. The pathogens E. canis and Anaplasma platys (transmitted by salivation) were detected, as well as 75 species of potential pathogens recorded in this tick that could enter the host in case of accidental regurgitation of the parasite (e.g., Staphylococcus, Streptococcus, Acinetobacter, Corynebacterium, Proteus, Clostridum, Klebsiella, Bacillus, Escherichia, Fusobacterium, and Pasteurella). It is necessary to continue analyzing the microbiota of ticks through massive sequencing for the benefit of public health and to establish new alternatives for controlling these parasites. Full article

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14 pages, 4477 KiB

Open AccessArticle

Trends in Bacterial and Candida Infections Before and Throughout the COVID-19 Pandemic

by Hassan Al Mana, Hashim Alhussain, Godwin Wilson, Hamad Abdel Hadi, Emad Ibrahim and Nahla O. Eltai

Microbiol. Res. 2024, 15(4), 2493-2506; https://doi.org/10.3390/microbiolres15040166 - 29 Nov 2024

Abstract

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)virus, resulted in significant global health consequences. The interventions introduced to limit the spread of the virus had a significant impact on the course of the pandemic, but they might also involve [...] Read more.

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)virus, resulted in significant global health consequences. The interventions introduced to limit the spread of the virus had a significant impact on the course of the pandemic, but they might also involve other pathogens besides SARS-CoV-2. This study investigates the epidemiological variations for major bacterial and common fungal pathogens represented by Candida species infection in Qatar through retrospective hospital records. Retrospective data were collected on all bacterial and Candida infections from Hamad General Hospital between January 2019 and December 2021. Statistical analyses were performed using R (Version 4.1.0). Infection count comparisons were performed using chi-square goodness of fit tests. Differences in patient numbers were tested with one-way ANOVA followed by post hoc Tukey HSD. The number of infections and measures were correlated using Spearman rank correlation. The significance level was set at 0.05, and where applicable, the Holm–Bonferroni method was used to correct for multiple testing. The general trend for bacterial and Candida infections showed a significant decrease (p < 0.05) following the imposed restrictions and increases during restriction lifting periods. The number of bacterial infections correlated with the number of international visitors (ρ = 0.61, p < 0.01), while the number of Candida infections correlated with hospital admissions of COVID-19 patients (ρ = 0.59, p = 0.013). The results provide a general overview of the infection trends in Qatar during the COVID-19 pandemic and illustrate some of the pandemic interventions’ effects on bacterial and Candida infections. However, further research is needed to better understand the underlying trend dynamics. Full article

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38 pages, 1573 KiB

Open AccessReview

Sex- and Gender-Specific Considerations in Mycotoxin Screening: Assessing Differential Exposure, Health Impacts, and Mitigation Strategies

by Gayathree Thenuwara, Bilal Javed, Baljit Singh, Hugh J. Byrne and Furong Tian

Microbiol. Res. 2024, 15(4), 2455-2492; https://doi.org/10.3390/microbiolres15040165 - 29 Nov 2024

Abstract

Mycotoxins, toxic secondary metabolites produced by fungi, present significant health risks through contaminated food and feed. Despite broad documentation of their general impacts, emerging research highlights the requirement of addressing both sex- and gender-specific differences in the risk of exposure, susceptibility, and health [...] Read more.

Mycotoxins, toxic secondary metabolites produced by fungi, present significant health risks through contaminated food and feed. Despite broad documentation of their general impacts, emerging research highlights the requirement of addressing both sex- and gender-specific differences in the risk of exposure, susceptibility, and health outcomes in mycotoxin screening and mitigation strategies. Distinct biological (sex-based) and sociocultural (gender-based) factors can influence the risk of mycotoxin exposure and subsequent health impacts; women may for example exhibit specific exposures to certain mycotoxins due to physiological and hormonal differences, with increased risks during critical life stages such as pregnancy and lactation. Conversely, men may demonstrate distinct metabolic and immune responses to these toxins. Socioeconomic and cultural factors also contribute to gender-specific exposure risks, including occupational exposures, dietary habits, and healthcare access. Current mycotoxin screening methodologies and regulatory frameworks often disregard these sex and gender disparities, resulting in incomplete risk assessments and suboptimal public health interventions. This review addresses the incorporation of sex- and gender-specific data into mycotoxin research, the development of advanced screening techniques, and the implementation of targeted mitigation strategies. Addressing these sex and gender differences is crucial for enhancing the efficacy of mycotoxin management policies and safeguarding public health. Future research directions and policy recommendations are discussed to promote a more comprehensive and practical approach to mycotoxin risk assessment and control. Full article

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20 pages, 810 KiB

Open AccessReview

Sensitivity of Collagenolytic Periopathogenic Microorganisms to Chlorhexidine Solution: A Comprehensive Review of In Vitro Studies

by Bruno Barbosa, Filipe Castro, Jorge Pereira, Maria Catarino, Jaime Guimarães and Gustavo Vicentis Oliveira Fernandes

Microbiol. Res. 2024, 15(4), 2435-2454; https://doi.org/10.3390/microbiolres15040164 - 27 Nov 2024

Abstract

Objective: This review evaluated chlorhexidine (CHX)’s beneficial effect as an antibacterial substance on periodontopathogenic bacteria, which can influence the preservation of periodontal tissues and biomaterials. Methods: A search was performed in the PubMed/MedLine, B-On, ScienceDirect, and Cochrane Library databases. In vitro studies published [...] Read more.

Objective: This review evaluated chlorhexidine (CHX)’s beneficial effect as an antibacterial substance on periodontopathogenic bacteria, which can influence the preservation of periodontal tissues and biomaterials. Methods: A search was performed in the PubMed/MedLine, B-On, ScienceDirect, and Cochrane Library databases. In vitro studies published between 1 January 2000 and 31 December 2023 in the English language were included; studies that did not correlate the sensitivity of collagenolytic microorganisms to CHX and observational and in vivo studies were excluded. The Quality Assessment Tool for In Vitro Studies (QUIN) evaluated the risk of bias. Results: Eight studies were included; six assessed the inhibitory effect of CHX on the activity of various bacteria associated with periodontitis and collagen degradation; two studies evaluated the same effect only for P. gingivalis. All the studies had an evaluation percentage above 70%, representing a low bias risk. Conclusions: There is a relationship between collagen degradation and the microorganisms in periodontal diseases. CHX showed efficacy against various microorganisms, inhibiting their growth and cell viability. CHX demonstrated significant implications for preventing and treating infections associated with collagen degradation. Full article

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10 pages, 1125 KiB

Open AccessArticle

Comparison of Gut Microbiota in Overwintering Bees: Apis cerana vs. Apis mellifera

by Heng Chen, Lijiao Gao, Jialin Liu, Conghui Ji, Xiaoqun Dang, Zeyang Zhou and Wenhua Luo

Microbiol. Res. 2024, 15(4), 2425-2434; https://doi.org/10.3390/microbiolres15040163 - 26 Nov 2024

Abstract

Bees play important roles in socio-economic development, biodiversity conservation, and ecosystem stability. However, during the cold season, resources become limited, leading to significant losses in bee colonies. Although many studies have described the characteristics of winter bees and demonstrated that notable changes occur [...] Read more.

Bees play important roles in socio-economic development, biodiversity conservation, and ecosystem stability. However, during the cold season, resources become limited, leading to significant losses in bee colonies. Although many studies have described the characteristics of winter bees and demonstrated that notable changes occur in their gut microflora, the underlying mechanisms remain yet to be fully elucidated. Therefore, this study was conducted to compare the gut microbiota dynamics of overwintering bees. Sample acquisition involved randomly selecting ten colonies each from three bee farms containing Apis cerana (AC) and Apis mellifera (AM), followed by dissection for further analysis. DNA was extracted, and 16S rDNA sequencing, along with various bioinformatics tools, was used to assess microbial diversity, functional differences, and species comparisons between AC and AM gut microbiota. AC exhibited lower β diversity in the gut microbiota than AM during winter. Moreover, Gilliamella and Apibacter were relatively more abundant in AC. Regarding microbial functions, key pathways included the phosphotransferase system, galactose metabolism, the pentose phosphate pathway, and carbohydrate transport and metabolism. These results suggest the presence of microbial diversity differences between AC and AM, with the differential microbial functions mainly enriched in metabolic pathways that facilitate adaptation to cold environmental stress. Full article

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11 pages, 2068 KiB

Open AccessArticle

The Fungus Phlebiopsis flavidoalba’s Pathogenicity and Virulence Toward the Fluted Scale (Praelongorthezia acapulcoa) Pest of Rice and Sugarcane Crops

by Silvia Hernández-Hernández, Facundo Muñiz-Paredes, Guadalupe Peña-Chora and Víctor Manuel Hernández-Velázquez

Microbiol. Res. 2024, 15(4), 2414-2424; https://doi.org/10.3390/microbiolres15040162 - 26 Nov 2024

Abstract

Sugarcane is one of the main crops in Morelos State, Mexico. The presence of the insect pest Praelongorthezia acapulcoa (Morrison), commonly known as the fluted scale insect, was observed in sugarcane and rice crops, causing losses of up to 30% of production in [...] Read more.

Sugarcane is one of the main crops in Morelos State, Mexico. The presence of the insect pest Praelongorthezia acapulcoa (Morrison), commonly known as the fluted scale insect, was observed in sugarcane and rice crops, causing losses of up to 30% of production in both crops. In this work, a fungus isolated from the mycosic cadavers of P. acapulcoa was identified as the basidiomycete Phlebiopsis flavidoalba (Cooke) Hjortstam via morphological and molecular identification using the ITS, tef 1, and 28S regions. Its pathogenicity toward P. acapulcoa was verified in laboratory tests, causing a mortality rate higher than 60%. Its virulence toward P. acapulcoa, estimated as the mean lethal concentration (LC₅₀), was 9.7 × 10⁶ conidia mL⁻¹. This work constitutes the first report about a basidiomycete with direct entomopathogenic activity and biological control of the fluted scale insect, P. acapulcoa. Full article

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20 pages, 839 KiB

Open AccessArticle

Bacterial Agents for Biocontrol of American Foulbrood (AFB) of Larvae Honey Bee

by Piotr Nowotnik, Paweł Chorbiński, Paweł Migdał and Bogusław Górski

Microbiol. Res. 2024, 15(4), 2394-2413; https://doi.org/10.3390/microbiolres15040161 - 24 Nov 2024

Abstract

Bee colonies are constantly threatened by a bacterial larvae disease called American foulbrood, caused by the Gram-positive bacterium Paenibacillus larvae. This is a highly specialized pathogen with only one established host, the honey bee larvae. The current state of legislation throughout the [...] Read more.

Bee colonies are constantly threatened by a bacterial larvae disease called American foulbrood, caused by the Gram-positive bacterium Paenibacillus larvae. This is a highly specialized pathogen with only one established host, the honey bee larvae. The current state of legislation throughout the European Union prevents the inclusion of pharmacotherapy treatment, and the only control is based on the physical elimination of infected colonies upon veterinary orders. The purpose of this study was to investigate the antimicrobial activity of selected bacteria with proven probiotic potential with typical characteristics meeting the definition of a probiotic that could reduce the American foulbrood pressure by promoting the development of the larvae microbiome that competes with and blocks the excessive proliferation and production of P. larvae endospores. The antimicrobial activity of inoculants of the following selected strains was studied: Bacillus pumilus, Bacillus licheniformis, Streptomyces narbonensis, Lysinibacillus fusiformis, Levilactobacillus brevis, Bacillus megaterium against Paenibacillus larvae ATCC 9545 (formerly Paenibacillus larvae sub sp. larvae), and Paenibacillus larvae CCUG 48973. Analyses were performed by the well diffusion method according to EUCAST standards (clinical breakpoints and dosing of antibiotics) with modifications due to the specificity of the bacteria used. The largest zone of growth inhibition of P. larvae was confirmed with S. narbonensis, B. licheniformis, and B. megaterium, and medium activity was observed with L. brevis and B. pumilus. Negligible activity was shown by L. fusiformis. Differences were noticed in the resistance of indicator strains of P. larvae and between the media and carriers used. Full article

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13 pages, 1421 KiB

Open AccessArticle

Antibiotic-Producing Bacteria Collected from Seawater

by Khadijah M. Dashti, Leila Vali, Norya Almaraghi, Hussain Ebrahim, Hassan Abul and Ali A. Dashti

Microbiol. Res. 2024, 15(4), 2381-2393; https://doi.org/10.3390/microbiolres15040160 - 23 Nov 2024

Abstract

Background: Microorganisms are a known source of antibiotics. The study aimed to identify and screen antibiotic-producing microbes isolated from seawater. Method: Three of the fifty (50) bacteria isolated from seawater showed positive for antibiotic activity. The antimicrobial activity of Pseudomonas guguanensis (KD1) was screened [...] Read more.

Background: Microorganisms are a known source of antibiotics. The study aimed to identify and screen antibiotic-producing microbes isolated from seawater. Method: Three of the fifty (50) bacteria isolated from seawater showed positive for antibiotic activity. The antimicrobial activity of Pseudomonas guguanensis (KD1) was screened against the ESKAPE pathogens using agar-well diffusion assays. P. guguanensis (KD1) was selected for the fermentation and extraction of antimicrobial compounds using solvent extraction assays. Results: P. guguanensis (KD1) produced the highest antibacterial activity after 36 h of cultivation, inhibiting S. aureus, E. faecium, A. baumannii and E. cloacae. According to sensitization assay, K. pneumoniae was impermeable to all the cell-free supernatants of P. guguanensis (KD1). Using agar-well diffusion assays, ethyl acetate extracts from the supernatant recorded zones of inhibition against S. aureus, E. faecium, and E. cloacae, producing zones of 20.1 ± 0.432, 17.8 ± 0.121 and 16 ± 0.162 mm, respectively. Acetonitrile extract from the supernatant inhibited A. baumannii and S. aureus, forming zones of inhibition 18.2 ± 0.323 mm and 18 ± 0.234. The minimum inhibitory concentration and minimum bactericidal concentration recorded for the ethyl acetate extract and acetonitrile extract ranged from 1.56 to 6.25 mg/mL and 12.5–25 mg/mL, respectively. Conclusions: P. guguanensis (KD1) offers a potential source of antibiotics for infections caused by multidrug-resistant bacteria. Full article

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12 pages, 8474 KiB

Open AccessCommunication

Biological Traits of Vertically Seed-Transmitted Bacillus mojavensis in Triticum aestivum L.

by Roderic Gilles Claret Diabankana, Daniel Mawuena Afordoanyi, Maria Nikolaevna Filimonova, Shamil Zavdatovich Validov and Radik Ilyasovich Safin

Microbiol. Res. 2024, 15(4), 2369-2380; https://doi.org/10.3390/microbiolres15040159 - 22 Nov 2024

Abstract

Seed-borne endophytic bacteria can influence host responses to biotic and abiotic stress conditions. Their presence in seeds is related to their ability to colonize plant tissues and to pass from parent plants to offspring. In this study, we investigated the ability of Bacillus [...] Read more.

Seed-borne endophytic bacteria can influence host responses to biotic and abiotic stress conditions. Their presence in seeds is related to their ability to colonize plant tissues and to pass from parent plants to offspring. In this study, we investigated the ability of Bacillus mojavensis PS17 to pass into the next generation of spring wheat plants via seeds and the effect of the transmission mode on the functional traits of seed-transmitted colonies of PS17. The rifampicin-resistant PS17 strain at 100 µg/mL was used to track PS17 effectively throughout the wheat growth cycle. The results demonstrated the successful colonization of B. mojavensis PS17 and its ability to pass into the next plant generation through seeds. During plant development, the PS17 cell population was almost higher in the rhizosphere than in the aboveground parts of plants, including seeds at the grain-filling stage. The seed-transmitted B. mojavensis PS17 colonies exhibited identical biological traits to those of the parental PS17 strain. Bacillus mojavensis PS17 retained its ability to suppress the growth of pathogens, such as Fusarium oxysporum and Alternaria alternata, and produce hydrolases, including protease, lipase, amylase, and cellulase. These results highlight the potential of vertical transmission through seeds as a mode of spreading bacterial biocontrol agents in future plants. Full article

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11 pages, 9223 KiB

Open AccessCommunication

Scanning Electron Microscopy Analysis of Biofilm-Encased Bacteria Exposed to Cuprous Oxide-Impregnated Wound Dressings

by Tohar Roth, Einat Zelinger, Tally Kossovsky and Gadi Borkow

Microbiol. Res. 2024, 15(4), 2358-2368; https://doi.org/10.3390/microbiolres15040158 - 22 Nov 2024

Abstract

Microbial infections in wounds can significantly delay the healing process, with bacteria often forming protective biofilms that shield them from external threats. In this study, we evaluated the impact of copper oxide-impregnated wound dressings (referred to as COD) on a bacterial mixture comprising [...] Read more.

Microbial infections in wounds can significantly delay the healing process, with bacteria often forming protective biofilms that shield them from external threats. In this study, we evaluated the impact of copper oxide-impregnated wound dressings (referred to as COD) on a bacterial mixture comprising common Gram-positive and Gram-negative wound pathogens encased in biofilm. The bacterial mix was exposed to COD or control dressings for 0, 1, 2, and 3 h, and the effects were analyzed using scanning electron microscopy. After just 1 h of exposure to COD, notable leakage of bacterial cytoplasmic contents was observed. By the 3 h mark, the Gram-negative bacteria exhibited a formation of holes in their cell walls, while Gram-positive bacteria showed a reduction in cell width. These findings demonstrate the ability of COD to effectively kill bacteria even when protected by biofilm, supporting clinical observations of its efficacy in managing infected wounds. Full article

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17 pages, 2864 KiB

Open AccessArticle

A Metabarcoding Approach for Investigating the Stomach Microbiota of the Corallivorous Snail Coralliophila meyendorffii (Muricidae, Coralliophilinae) and Its Venomous Host, the Sea-Anemone Parazoanthus axinellae (Zoanthidea, Parazoanthidae)

by Chiara Benvenuti, Giulia Fassio, Valeria Russini, Maria Vittoria Modica, Marco Oliverio, Domenico Davolos and Elisa Nocella

Microbiol. Res. 2024, 15(4), 2341-2357; https://doi.org/10.3390/microbiolres15040157 - 21 Nov 2024

Abstract

The corallivorous snails Coralliophila meyendorffii and its coral host Parazoanthus axinellae are appealing candidates for studying symbiotic interactions at the microbiome level. In this study, we investigated for the first time the microbial community in the stomach of C. meyendorffii and in the [...] Read more.

The corallivorous snails Coralliophila meyendorffii and its coral host Parazoanthus axinellae are appealing candidates for studying symbiotic interactions at the microbiome level. In this study, we investigated for the first time the microbial community in the stomach of C. meyendorffii and in the polyps of its coral host P. axinellae using as markers multiple regions of the 16S rRNA gene. The bacterial community in the stomach of another corallivorous snail, Babelomurex cariniferus, that feeds on Cladocora hexacorals, was also investigated for comparison. The obtained results indicated the phylum Proteobacteria as the most abundant among the analysed samples, with Alphaproteobacteria and Gammaproteobacteria as the main classes. Among the investigated communities, some bacterial taxa were recognised in line with previous findings in the microbiota of marine invertebrates. As both organisms are exposed to the same bacteria in their habitats, this might suggest shared environmental influences for their microbiota composition. Most of the detected taxa found exclusively or predominantly in P. axinellae samples suggest the presence of holobiont components within the microbial community of this coral, mirroring those identified in other corals, while the stomach microbiome of C. meyendorffii did not indicate a primary role in parasitism. Finally, we provide evidence that many of these bacterial taxa are horizontally transferred between Parazohantus and Corallliophila. Full article

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11 pages, 386 KiB

Open AccessArticle

Effect of an Add-On Multi-Strain Probiotic Formulation in the Prevention of Recurrent Urinary Tract Infections: A Double-Blind Randomized Placebo-Controlled Trial

by Archana Mishra, Saubhagya Kumar Jena, Anand Srinivasan, Amruta Tripathy, Rituparna Maiti and Debasish Hota

Microbiol. Res. 2024, 15(4), 2330-2340; https://doi.org/10.3390/microbiolres15040156 - 16 Nov 2024

Abstract

Urinary tract infections (UTIs) present a significant health challenge for women globally, particularly due to high recurrence rates. This randomized, double-blinded, placebo-controlled study conducted at AIIMS Bhubaneswar, India, evaluated the effectiveness of a multi-strain lactobacilli probiotic formulation as an adjunct to standard antibiotic [...] Read more.

Urinary tract infections (UTIs) present a significant health challenge for women globally, particularly due to high recurrence rates. This randomized, double-blinded, placebo-controlled study conducted at AIIMS Bhubaneswar, India, evaluated the effectiveness of a multi-strain lactobacilli probiotic formulation as an adjunct to standard antibiotic therapy in preventing recurrent UTIs. Fifty-one adult women (18–50 years) with recurrent UTIs received either the probiotic or a placebo for 24 weeks. The primary outcome was UTI recurrence, while secondary outcomes included the number of UTI episodes and changes in urinary nerve growth factor (NGF) and serum macrophage colony-stimulating factor (M-CSF) levels. The results showed a significant reduction in UTI recurrence in the probiotic group, with 75% remaining recurrence-free, compared to 33% in the placebo group (p = 0.007). The relative risk for recurrence absence was 2.67 (95% CI: 1.19–5.99). Although the mean number of UTI episodes decreased in the probiotic group, the difference was not statistically significant (p = 0.379). The urinary NGF and serum M-CSF levels significantly decreased from baseline in both groups, but there were no significant differences between them. This study suggests probiotics may be a valuable adjunct therapy for preventing recurrent UTIs. Full article

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