Journal Description
Microbiology Research
Microbiology Research
is an international, scientific, peer-reviewed open access journal published quarterly online by MDPI (from Volume 11 Issue 2-2020).
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, ESCI (Web of Science), Embase, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.7 days after submission; acceptance to publication is undertaken in 3.5 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Impact Factor:
2.1 (2023);
5-Year Impact Factor:
2.0 (2023)
Latest Articles
Examining the Diversity of Rhizosphere Soil Bacterial Communities and Screening of Growth-Promoting Bacteria from the Rhizosphere Soil of Haloxylon ammodendron in Xinjiang
Microbiol. Res. 2024, 15(3), 1346-1358; https://doi.org/10.3390/microbiolres15030091 (registering DOI) - 27 Jul 2024
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The bacterial communities in rhizosphere soil interact with the roots of plants. This interaction is beneficial for both the bacteria and the plants, which makes it very important to identify the structure of these bacterial communities for plant growth and development. However, the
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The bacterial communities in rhizosphere soil interact with the roots of plants. This interaction is beneficial for both the bacteria and the plants, which makes it very important to identify the structure of these bacterial communities for plant growth and development. However, the composition characteristics of bacterial communities in rhizosphere soil of 2-year and 5-year Haloxylon ammodendron have not been clearly defined. The purpose of this study was to identify the diverse composition of 2-year and 5-year Haloxylon ammodendron in Turpan, Xinjiang. Thus, rhizosphere soil bacteria were analyzed by isolating, purifying, and identifying the species through high-throughput sequencing technology. The bacterial strains in the rhizosphere soil of Haloxylon ammodendron were isolated with the dilution coating method, resulting in 37 isolated strains. The selective media were used to screen the growth-promoting characteristics of the rhizosphere soil isolates of Haloxylon ammodendron. The results of high-throughput amplification sequencing showed that the rhizosphere bacteria in the 2-year rhizosphere soil belonged to 45 phyla, 109 classes, 288 orders, 451 families, 826 genera, and 404 species, and those in the 5-year rhizosphere soil belonged to 56 phyla, 148 classes, 369 orders, 601 families, 1062 genera, and 671 species. Among them, Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, Crenarchaeota, and so on are the dominant bacteria. There were 12206 and 14,053 OTUs in the 2-year-old and 5-year-old rhizosphere soil bacteria, respectively, and 3329 OTUs in the 2-year- and 5-year-old rhizosphere soil, accounting for 16.98% of the total number of OTUs. The results showed that three strains, sg16, sg21, and ss4, had the highest inorganic phosphorus solubility index (1.58). The isolated strain did not have the ability to dissolve organophosphorus and potassium, while the screened strain sg16 had the ability to fix nitrogen. Two strains with a good iron-bearing capacity, Sg9F and Sg1, were screened, among which Sg9F had the highest D/d value and Sg9F had the strongest iron-bearing capacity. The results showed that 37 strains of rhizosphere soil bacteria belonged to six genera. They are Bacillus, Corynebacterium, Phyllobacterium, Lysinibacillus, Sinorhizobium meliloti, and Streptomyces levis. Among them are sg21 (Bacillus sp.), sg1 (Bacillus sp.), sg9F (Streptomyces levis), sg16 (Phyllobacterium phragmitis), and ss4 (Sinorhizobium meliloti). This study provides a particular research basis for the influence of Haloxylon ammodendron rhizosphere bacteria on soil nutrient release and depicts a solution for improving the yield and quality of cistanche deserticola indirectly through isolating, screening, and identifying rhizosphere soil bacteria, including screening strains with growth-promoting functions and analyzing the population structure of rhizosphere bacteria in 2- and 5-year soil in combination with high-throughput sequencing technology.
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Open AccessArticle
Influence of Mutations on Physicochemical Properties of Spike Proteins from Prototypical SARS-CoV-2 Variants of Concern Detected in Amazonian Countries
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Adriana Conceição B. Silva and Carlos Alberto M. Carvalho
Microbiol. Res. 2024, 15(3), 1334-1345; https://doi.org/10.3390/microbiolres15030090 (registering DOI) - 27 Jul 2024
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Since the emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the viral spike protein (S) has become a target to describe appropriate epitopes for vaccine development and to carry out epidemiological surveillance, especially regarding the variants of concern (VOCs). This study aimed
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Since the emergence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the viral spike protein (S) has become a target to describe appropriate epitopes for vaccine development and to carry out epidemiological surveillance, especially regarding the variants of concern (VOCs). This study aimed to evaluate the influence of mutations on physicochemical properties of S proteins from prototypical SARS-CoV-2 VOCs detected in Amazonian countries. Using multiple computational tools, seven VOCs (B.1.1.7/P.1/B.1.617.2/BA.1/BA.2/BA.4/BA.5) were identified and compared to the ancestral lineage of the virus (B). In all variants, most amino acids were nonpolar; among the polar amino acids, B.1.617.2/BA.1/BA.2/BA.4/BA.5 presented a slightly higher proportion of basic residues and a lower proportion of neutral residues. Unlike B.1.1.7/P.1/B.1.617.2, BA.1/BA.2 had a greater content of secondary structures, such as α-helices and β-sheets. Regarding post-translational modifications, BA.2/BA.4/BA.5 presented fewer glycosylations and phosphorylations. Finally, a more prominent antigenic propensity in the N-terminal domain of BA.2/BA.4/BA.5 and in the receptor-binding domain of B.1.617.2/BA.4/BA.5 was observed. In conclusion, the omicron variants of SARS-CoV-2 presented greater sequence variability in S proteins compared to the other VOCs, influencing structural aspects that can potentially modulate its interaction with cellular receptors and recognition by the immune system.
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Open AccessBrief Report
Germination and Culturability after UV Irradiation of Metarhizium anisopliae Native from Soils of Tropical Cattle Farms
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Miguel Ángel Alonso-Díaz, María de Lourdes Lozano-Velázquez, Iván Adrián García-Galicia and Agustín Fernández-Salas
Microbiol. Res. 2024, 15(3), 1326-1333; https://doi.org/10.3390/microbiolres15030089 - 25 Jul 2024
Abstract
The use of entomopathogenic fungi (EF) is a promising alternative for the control of Rhipicephalus microplus, an important tick affecting cattle globally. This study aimed to evaluate the effect of ultraviolet irradiation (UV) exposure on the percentage of conidia germination and number
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The use of entomopathogenic fungi (EF) is a promising alternative for the control of Rhipicephalus microplus, an important tick affecting cattle globally. This study aimed to evaluate the effect of ultraviolet irradiation (UV) exposure on the percentage of conidia germination and number of colony-forming units of eight strains of Metarhizium anisopliae (MaV55, MaV35, MaV31, MaV25, MaV13, Ma08, MaV05, and MaV02). The UV (UV-A and UV-A+B) irradiation was carried out with an ultraviolet radiation emission lamp. The conidia of each strain were exposed to the UV irradiation treatments for 3 h. MaV25, MaV08, MaV05, MaV13, and MaV31 showed higher tolerance to UV-A radiation exposure, as assessed by conidia germination. UV-A+B radiation decreased the germination percentage of all the M. anisopliae strains. The eight evaluated strains showed good tolerance to UV-A radiation, as assessed by the development of colony-forming units (CFU). UV-A+B radiation did not significantly affect (p > 0.05) the count of the CFU of six of the M. anisopliae strains evaluated (MaV35, MaV13, MaV08, MaV05, MaV31, and MaV02). The novel findings of the UV-tolerant M. anisopliae strains may potentially improve the effectiveness of EF under environmental conditions. Integral research under real tropical conditions is advised to evaluate the effectiveness of the EF strains.
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(This article belongs to the Special Issue Veterinary Microbiology and Diagnostics)
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Open AccessBrief Report
IL-26 Increases Sensing of Borrelia burgdorferi DNA by Human Toll-like Receptor 9
by
Andre Taylor, Chin Griffin, Kedzie Arrington, Jose Barragan and Jorge Cervantes
Microbiol. Res. 2024, 15(3), 1319-1325; https://doi.org/10.3390/microbiolres15030088 - 24 Jul 2024
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Background: IL-26 has demonstrated antimicrobial properties, as well as in the degradation of DNA from the Lyme disease spirochete Borrelia burgdorferi (Bb). Additionally, IL-26 can promote macrophage activation and enhance Bb phagocytotic activity. It is unclear if cell-mediated immune responses are modulated through
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Background: IL-26 has demonstrated antimicrobial properties, as well as in the degradation of DNA from the Lyme disease spirochete Borrelia burgdorferi (Bb). Additionally, IL-26 can promote macrophage activation and enhance Bb phagocytotic activity. It is unclear if cell-mediated immune responses are modulated through TLR9 signaling when exposed to IL-26 Bb DNA complexes in post-treatment Lyme disease syndrome (PTLDS). Objective: We here aim to explore the effect of IL-26 in human Toll-like receptor (TLR)-9’s activation upon the recognition of Bb DNA. Methods: We utilized a single-receptor cell system, HEK-Dual™ hTLR9 cells, which harbors two reporter plasmids for the NF-κB and IL-8 signaling pathways. Bb DNA was exposed to increasing concentrations of IL-26 in monomeric or dimeric form and then used to stimulate the cells for 4 h. The TLR-9 ligand CpG was used as a control. Results: We observed that NF-κB and IL-8 activation was maximal when the cells were stimulated with Bb DNA that had been treated with 5 µM of IL-26 monomer and 1 µM of IL-26 dimer. The same was observed for IL-8 activation upon CpG stimulation. We observed, however, a decrease in NF-κB activation when treated with either form of IL-26. An NF-κB activation increase did not occur with IL-26-treated TLR9 ligand CpG. Conclusions: Our study shows an enhancement in NF-κB and IL-8 activation upon the recognition of IL-26-treated Bb DNA by TLR9, which suggests an increase in sensing by the TLR9 of Bb DNA when it is in the form of an IL-26-Bb DNA complex. These findings will prompt further studies on the interaction between IL-26 and Bb DNA.
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Open AccessArticle
Exploring the Antimicrobial and Probiotic Potential of Microorganisms Derived from Kazakh Dairy Products
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Sandugash Anuarbekova, Zhandarbek Bekshin, Serik Shaikhin, Gulzhan Alzhanova, Azamat Sadykov, Aslan Temirkhanov, Zinigul Sarmurzina and Yerkanat N. Kanafin
Microbiol. Res. 2024, 15(3), 1298-1318; https://doi.org/10.3390/microbiolres15030087 - 23 Jul 2024
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The emergence of antibiotic-resistant pathogens in clinical settings has intensified the search for new probiotic strains with both health benefits and technological utility. This study aims to identify and characterize promising antimicrobial cultures derived from milk and dairy products, capable of inhibiting opportunistic
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The emergence of antibiotic-resistant pathogens in clinical settings has intensified the search for new probiotic strains with both health benefits and technological utility. This study aims to identify and characterize promising antimicrobial cultures derived from milk and dairy products, capable of inhibiting opportunistic pathogens. The samples of dairy products were collected from various markets across Kazakhstan. Microorganisms isolated from these samples underwent identification through 16S rRNA and ITS gene sequencing, using the BLAST algorithm. Their antimicrobial activity was assessed using the delayed antagonism method against pathogenic microorganisms including E. coli, S. aureus, Pseudomonas sp., Candida sp., and B. subtilis. Additionally, the isolates were evaluated for resistance to environmental stress factors such as temperature, pH, salt, ethanol, glucose, and peroxide. From 24 distinct samples, 33 isolates were purified, with 15 demonstrating high viability (108–109 CFU/mL) and stress resistance. Notably, Lacticaseibacillus casei AK and Enterococcus faecium KS exhibited resistance to all tested stress conditions. Antimicrobial screening revealed strong activity by strains LP, LB, and S-2 against multiple pathogens. Genotyping and carbohydrate fermentation tests identified these effective isolates as belonging to the genera Lactobacillus, Lactococcus, Enterococcus, Lactiplantibacillus, Streptococcus, and the yeast genus Pichia. This study underscores the industrial and health potential of the identified microorganisms. Prominent among the strains, Lactiplantibacillus pentosus LP, Lacticaseibacillus casei AK, Lactiplantibacillus argentoratensis LB, Lactiplantibacillus plantarum S-2, and Enterococcus faecium KS have been recognized as potent probiotics. These strains exhibit broad-spectrum antimicrobial activity coupled with robust stress tolerance, making them suitable candidates for probiotic applications.
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Open AccessArticle
In Vitro and In Vivo Wide-Spectrum Dual Antimycetomal Activity of Eight Essential Oils Coupled with Chemical Composition and Metabolomic Profiling
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Shereen O. Abd Algaffar, Prabodh Satyal, Naglaa S. Ashmawy, Annelies Verbon, Wendy W. J. van de Sande and Sami A. Khalid
Microbiol. Res. 2024, 15(3), 1280-1297; https://doi.org/10.3390/microbiolres15030086 - 22 Jul 2024
Abstract
Mycetoma, a neglected infection of subcutaneous tissues, poses a significant health burden, especially in tropical regions. It is caused by fungal (eumycetoma) and bacterial (actinomycetoma) pathogens, with current treatments often providing unsatisfactory outcomes. This study aims to discover novel broad-spectrum antimicrobial agents to
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Mycetoma, a neglected infection of subcutaneous tissues, poses a significant health burden, especially in tropical regions. It is caused by fungal (eumycetoma) and bacterial (actinomycetoma) pathogens, with current treatments often providing unsatisfactory outcomes. This study aims to discover novel broad-spectrum antimicrobial agents to circumvent the lengthy and costly diagnostic procedures. Eight essential oils (EOs) from the roots and aerial parts of Geigeria alata, Lavandula angustifolia, Melaleuca alternifolia, Myristica fragrans, Pimpinella anisum, Syzigum aromaticum, and Thymus vulgaris were prepared using steam distillation. The in vitro antimycetomal activity against Madurella mycetomatis and Actinomadura madurae strains was assessed using resazurin assays. The chemical compositions of the EOs were analyzed using gas chromatography and mass spectrometry (GC–MS). Promising EOs underwent further in vivo toxicity and efficacy testing in Galleria mellonella larvae models. EOs of G. alata roots, M. fragrans, P. anisum, S. aromaticum, and T. vulgaris showed wide-spectrum dual in vitro antimycetomal activity against all tested strains, with minimum inhibitory concentrations (MICs) ranging from 0.004 to 0.125% v/v. G. alata aerial parts and L. angustifolia EOs demonstrated activity predominantly against A. madurae, while M. alternifolia EO did not inhibit any tested strains. M. fragrans and P. anisum EOs significantly enhanced the survival of M. mycetomatis-infected larvae without inducing toxicity in uninfected larvae. Notably, P. anisum EO tended to enhance the survival of A. madurae-infected larvae, ranking it as the most promising EO among those tested. The investigated EOs, particularly P. anisum, exhibited promising broad-spectrum antimycetomal activity against fungal and bacterial pathogens responsible for mycetoma. These findings highlight the potential of essential oils as a basis for developing novel antimycetomal agents, offering hope for improved treatment strategies for this neglected disease.
Full article
(This article belongs to the Special Issue Antifungal Activities of Plant Extracts)
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Open AccessArticle
Exploring the Antibacterial Potential of Bile Salts: Inhibition of Biofilm Formation and Cell Growth in Pseudomonas aeruginosa and Staphylococcus aureus
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Anuradha Tyagi, Vinay Kumar, Navneet Joshi and Harish Kumar Dhingra
Microbiol. Res. 2024, 15(3), 1269-1279; https://doi.org/10.3390/microbiolres15030085 - 21 Jul 2024
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Chronic infections often involve notorious pathogens like Pseudomonas aeruginosa and Staphylococcus aureus, demanding innovative antimicrobial strategies due to escalating resistance. This investigation scrutinized the antibacterial prowess of bile salts, notably taurocholic acid (TCA), ursodeoxycholic acid (UDCA), and ox bile salt (OBS), against
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Chronic infections often involve notorious pathogens like Pseudomonas aeruginosa and Staphylococcus aureus, demanding innovative antimicrobial strategies due to escalating resistance. This investigation scrutinized the antibacterial prowess of bile salts, notably taurocholic acid (TCA), ursodeoxycholic acid (UDCA), and ox bile salt (OBS), against these pathogens. Evaluations encompassed minimum inhibitory concentration (MIC) determination, scrutiny of their impact on biofilm formation, and anti-virulence mechanisms. UDCA exhibited the highest efficacy, suppressing S. aureus and P. aeruginosa biofilms by 83.5% and 78%, respectively, at peak concentration. TCA also significantly reduced biofilm development by 81% for S. aureus and 75% for P. aeruginosa. Microscopic analysis revealed substantial disruption of biofilm architecture by UDCA and TCA. Conversely, OBS demonstrated ineffectiveness against both pathogens. Mechanistic assays elucidated UDCA and TCA’s detrimental impact on the cell membrane, prompting the release of macromolecular compounds. Additionally, UDCA and TCA inhibited protease and elastase synthesis in P. aeruginosa and staphyloxanthin and lipase production in S. aureus. These results underscore the potential of UDCA and TCA in impeding biofilm formation and mitigating the pathogenicity of S. aureus and P. aeruginosa.
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Open AccessArticle
Comparative Genome-Wide Analysis Underscores the Rapid Expansion of Cytochrome P450s for Secondary Metabolism in the Mycoparasite Pezizomycetes
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Puleng Rosinah Syed, Tiara Padayachee, Philasande Gamede, Bridget Valeria Zinhle Nkosi, David R. Nelson, Rajshekhar Karpoormath and Khajamohiddin Syed
Microbiol. Res. 2024, 15(3), 1251-1268; https://doi.org/10.3390/microbiolres15030084 - 20 Jul 2024
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Mycoparasite secondary metabolites control fungal infections or diseases in agriculture and human health. Among genes involved in synthesizing secondary metabolites, cytochrome P450 monooxygenases (CYPs/P450s) play a key role in synthesizing and attributing diversity to the secondary metabolites. Despite the importance of P450s, a
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Mycoparasite secondary metabolites control fungal infections or diseases in agriculture and human health. Among genes involved in synthesizing secondary metabolites, cytochrome P450 monooxygenases (CYPs/P450s) play a key role in synthesizing and attributing diversity to the secondary metabolites. Despite the importance of P450s, a comparative analysis of P450s in mycoparasites has yet to be reported. This study is aimed at addressing this research gap. Genome-wide analysis of P450s in 43 fungi representing six fungal phyla and three distinct lifestyles, such as mycoparasitic (24 species), saprophytic (5 species), and ectomycorrhizal (14 species), revealed the expansion of P450s in Pezizomycete mycoparasites for the synthesis of secondary metabolites. The number of P450s and their families and subfamilies, the number of secondary-metabolite biosynthetic gene clusters (SMBGCs), and the number of P450s that are part of these SMBGCs were found to be highest in Pezizomycete mycoparasites compared to their counterparts of saprophytes and ectomycorrhiza, indicating P450s also play a key role in mycoparasitism. An analysis of P450 location as part of SMBGCs and the available literature on Pezizomycete P450s revealed that P450s play a key role in the synthesis of anti-fungal secondary metabolites such as trichothecene sesquiterpene, harzianum A, heptelidic acid, and gliotoxin. The mycoparasite Trichoderma virens Tv29.8 P450 CYP68Q3 is found to be a bifunctional enzyme with epoxidation and oxidation capability, and CYP5117A3 performs a Baeyer–Villiger oxidation reaction with regioselectivity. This study serves as a reference for future annotation of P450s in mycoparasites.
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Open AccessArticle
Modulation of the Toll-like Receptor 3-Mediated Intestinal Immune Response by Water Kefir
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Stefania Dentice Maidana, Ramiro Ortiz Moyano, Mariano Elean, Yoshiya Imamura, Leonardo Albarracín, Fu Namai, Yoshihito Suda, Keita Nishiyama, Julio Villena and Haruki Kitazawa
Microbiol. Res. 2024, 15(3), 1239-1250; https://doi.org/10.3390/microbiolres15030083 - 20 Jul 2024
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Kefir has been associated with beneficial effects on its host’s health. The previous works examining the impact of kefir on the immune system focused on milk kefir or the exopolysaccharides and bacterial strains derived from it, while water kefir has not been evaluated.
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Kefir has been associated with beneficial effects on its host’s health. The previous works examining the impact of kefir on the immune system focused on milk kefir or the exopolysaccharides and bacterial strains derived from it, while water kefir has not been evaluated. Furthermore, studies have focused on kefir’s ability to modulate immune system hemostasis and exert anti-inflammatory effects, while its specific action on antiviral immunity has not been investigated. Thus, the aim of this work was to examine the potential immunomodulatory effects of water kefir on the intestinal innate antiviral immunity mediated by Toll-like receptor-3 (TLR3). Adult BALB/c mice fed water kefir ad libitum, diluted 1:5, 1:10, or 1:20 in the drinking water, for 6 consecutive days. On day 7, the treated groups and the untreated control mice received an intraperitoneal injection of the TLR3 agonist poly(I:C). Two days after the TLR3 activation, the intestinal damage and the innate immune response were studied. The intraperitoneal administration of poly(I:C) induced inflammatory-mediated intestinal tissue damage, characterized by the upregulation of interferons (IFNs), pro-inflammatory mediators (TNF-α, IL-15, IL-6), and factors involved in epithelial destruction (RAE-1 and NKG2D). The histological analysis of small intestinal samples showed that mice receiving water kefir 1:5 exhibited reduced edema and a lower inflammatory cell infiltration. Kefir-treated mice had significantly lower levels of serum LDH, AST, and ALT as well as intestinal TNF-α, IL-15, IL-6, RAE-1, and NKG2D. This group also showed higher concentrations of intestinal IFN-β, IFN-γ, and IL-10. The treatment with 1:10 of water kefir reduced intestinal damage and modulated cytokines but its effect was significantly lower than the 1:5 treatment, while the water kefir 1:20 did not modify the parameters evaluated compared to control mice. The results indicate that water kefir exerts its immunomodulatory effects in a dose-dependent manner. The in vivo studies allow us to speculate that water kefir can induce two beneficial effects on the intestinal TLR3-mediated immune response: the enhancement of antiviral defenses and the protection against the inflammatory-mediated tissue damage. These protective effects of water kefir require further exploration to understand how water kefir, or its specific molecules/strains, can influence the immune response and to determine the extent of its protection against a real viral challenge.
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Open AccessArticle
Transcriptional Regulation of the Genes Encoding Branched-Chain Aminotransferases in Kluyveromyces lactis and Lachancea kluyveri Is Independent of Chromatin Remodeling
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James González, Héctor Quezada, Jose Carlos Campero-Basaldua, Édgar Ramirez-González, Lina Riego-Ruiz and Alicia González
Microbiol. Res. 2024, 15(3), 1225-1238; https://doi.org/10.3390/microbiolres15030082 - 19 Jul 2024
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In yeasts, the Leu3 transcriptional factor regulates the expression of genes encoding enzymes of the leucine biosynthetic pathway, in which the first committed step is catalyzed by α-isopropylmalate synthase (α-IPMS). This enzyme is feedback inhibited by leucine, and its product, α-isopropylmalate (α-IPM), constitutes
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In yeasts, the Leu3 transcriptional factor regulates the expression of genes encoding enzymes of the leucine biosynthetic pathway, in which the first committed step is catalyzed by α-isopropylmalate synthase (α-IPMS). This enzyme is feedback inhibited by leucine, and its product, α-isopropylmalate (α-IPM), constitutes a Leu3 co-activator. In S. cerevisiae, the ScBAT1 and ScBAT2 genes encode branched-chain aminotransferase isozymes. ScBAT1 transcriptional activation is dependent on the α-IPM concentration and independent of chromatin organization, while that of ScBAT2 is α-IPM-independent but dependent on chromatin organization. This study aimed at understanding whether chromatin remodeling determines the transcriptional regulation of orthologous KlBAT1 and LkBAT1 genes in Kluyveromyces lactis and Lachancea kluyveri under conditions in which the branched-chain amino acids are synthesized or degraded. The results indicate that, in K. lactis, KlBAT1 expression is reduced under catabolic conditions, while in L. kluyveri, LkBAT1 displays a constitutive expression profile. The chromatin organization of KlBAT1 and LkBAT1 promoters did not change, maintaining the Leu3-binding sites free of nucleosomes. Comparison of the α-IPMS sensitivities to feedback inhibition suggested that the main determinant of transcriptional activation of the KlBAT1 and LkBAT1 genes might be the availability of the α-IPM co-activator, as reported previously for the ScBAT1 gene of S. cerevisiae.
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Open AccessArticle
New Insights into Molecular Characterization, Antimicrobial Resistance and Virulence Factors of Methicillin-Sensitive Coagulase-Positive Staphylococcus spp. from Dogs with Pyoderma and Otitis Externa
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Faten Ben Chehida, Wafa Tombari, Haythem Gharsa, Youssef Rabia, Sana Ferhi, Maha Jrad and Lilia Messadi
Microbiol. Res. 2024, 15(3), 1208-1224; https://doi.org/10.3390/microbiolres15030081 - 12 Jul 2024
Abstract
The first Tunisian national molecular survey of coagulase-positive staphylococci (CoPS) isolated from dogs with pyoderma and otitis externa was conducted to evaluate the prevalence of CoPS and identify its phenotypic and genotypic diversities. A total of 99 out of the 195 samples collected
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The first Tunisian national molecular survey of coagulase-positive staphylococci (CoPS) isolated from dogs with pyoderma and otitis externa was conducted to evaluate the prevalence of CoPS and identify its phenotypic and genotypic diversities. A total of 99 out of the 195 samples collected from 39 sick dogs were identified across multiple sites as methicillin-susceptible CoPS belonging to the species S. pseudintermedius (64.4%), S. aureus (20.2%), S. coagulans (10.1%), and S. hyicus (5%). Fifteen sampled dogs carried more than one Staphylococcus species. Their antibiotic resistance and virulence factors were determined using conventional and molecular methods. Of the S. pseudintermedius isolates found, 17.4% were multidrug-resistant, whereas high rates of virulence genes were observed among the S. aureus isolates. On polystyrene surfaces, 75% of S. aureus isolates were biofilm producers, of which 15% were classified as strong producers. The capsular polysaccharide cap8 genotype was predominant among them. A MultiLocus Sequence Typing (MLST) analysis clustered the S.aureus isolates into five distinct sequence types (STs), with four assigned for the first time. Our findings highlight the spread of CoPS among diseased dogs and, especially, the emergence of S. hyicus, S. coagulans, multidrug-resistant S. pseudintermedius and S. aureus isolates with high genetic variability. The precise characterization of these strains, as well as their continuous monitoring, is necessary for the implementation of preventive strategies given the significant public health risk.
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(This article belongs to the Special Issue Veterinary Microbiology and Diagnostics)
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Open AccessArticle
Predictive Modeling of UV-C Inactivation of Microorganisms in Glass, Titanium, and Polyether Ether Ketone
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Amira Chroudi, Talita Nicolau, Narayan Sahoo, Óscar Carvalho, Andrea Zille, Samir Hamza and Jorge Padrão
Microbiol. Res. 2024, 15(3), 1189-1207; https://doi.org/10.3390/microbiolres15030080 - 5 Jul 2024
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Biomaterials consist of both natural and synthetic components, such as polymers, tissues, living cells, metals, and ceramics. Their purpose is focused on repairing or replacing malfunctioning living tissues and organs. Therefore, it is imperative to ensure the safety and sterility of biomaterials before
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Biomaterials consist of both natural and synthetic components, such as polymers, tissues, living cells, metals, and ceramics. Their purpose is focused on repairing or replacing malfunctioning living tissues and organs. Therefore, it is imperative to ensure the safety and sterility of biomaterials before any contact with living tissue. Ultraviolet (UV)-C irradiation for biomaterial disinfection has been considered due to the high recurrence rate of bacterial infections and to prevent resistance. Physical composition and surface properties and UV-C sensitivity of microorganisms can alter its efficacy. The main objective of this study was to evaluate the efficacy of UV-C in terms of microbial lethality and additional underlying factors contributing to its performance, namely the surface properties. For this purpose, twelve different strains were first screened, from which four microorganism species known to have the ability to cause nosocomial infections were further tested, namely Escherichia coli, Pseudomonas aeruginosa, Candida albicans, and Candida glabrata. These microorganisms were inoculated onto slides and disks of various bio contact surfaces, including glass (GLS), titanium (Ti), and poly ether etherketone (PEEK), and exposed to UV-C. The results demonstrate that bacterial pathogens on biomaterial surfaces respond differently to UV-C light exposure, and the bactericidal effect decreased in this order: glass, PEEK, and Ti (0.5 to 2.0 log reduction differences). P. aeruginosa ATCC 27853 on glass surfaces was reduced to an undetectable level after being exposed to 6.31 J.cm−2 of UV-C, displaying the highest reduction rate observed among all the tested microorganisms, 2.90 J−1.cm−3, compared to Ti and PEEK. Similarly, a higher reduction in C. glabrata ATCC 2001 was observed on glass; the modeled inhibition displayed a rate of 1.30 J−1.cm−3, the highest observed rate among yeast, compared to Ti and PEEK, displaying rates of 0.10 J−1.cm−3 and 0.04 J−1.cm−3, respectively. The inactivation rates were higher for less hydrophobic materials with smoother surfaces as compared to biomaterials with rougher surfaces.
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Open AccessArticle
Limosilactobacillus reuteri and Its Probiotic Potential against Cariogenic Bacteria
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Brianda Karina Félix-Sicairos, Rita Elizabeth Martinez-Martinez, Saray Aranda-Romo, Roberto Gonzalez-Amaro, Mariana Salgado-Bustamante, Norma Verónica Zavala-Alonso and Ángel Gabriel Alpuche-Solís
Microbiol. Res. 2024, 15(3), 1178-1188; https://doi.org/10.3390/microbiolres15030079 - 3 Jul 2024
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Bacteriotherapy is a promising option in addressing dental caries, a persistent global public health challenge with multifactorial origin, including dysbiosis. Despite the exploration of various probiotics, outcomes remain inconclusive. Objective: This study aimed to assess the inhibitory potential of L. reuteri and other
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Bacteriotherapy is a promising option in addressing dental caries, a persistent global public health challenge with multifactorial origin, including dysbiosis. Despite the exploration of various probiotics, outcomes remain inconclusive. Objective: This study aimed to assess the inhibitory potential of L. reuteri and other potential probiotics like S. salivarius and S. oralis on the growth, adhesion, colonization, and viability of major cariogenic pathogens, comparing their probiotic efficacy. Methods: An in vitro experimental study was conducted, encompassing direct competition assays in solid and liquid co-culture tests and the characterization of adhesion to dental enamel and cell viability by life or death assay. Results: L. reuteri exhibited the significant inhibition of S. sobrinus and S. mutans growth in both solid and liquid cultures, with statistically notable differences. Scanning electron microscopy and confocal microscopy demonstrated reduced cariogenic biofilm formation when combined with L. reuteri, corroborated by diminished bacterial viability and decreased dental enamel coverage. These findings underscore L. reuteri’s potential as an effective agent in caries prevention. Conclusion: The study suggests L. reuteri could serve as an effective probiotic in bacteriotherapy against dental caries. It displayed substantial inhibitory activity in vitro against cariogenic bacteria, impeding biofilm formation and adhesion, thereby impacting cell viability.
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Open AccessArticle
Comparative High-Throughput Sequencing Analysis of the Bacterial Community Associated with the Rhizosphere of Date Palm (Phoenix dactyllifera L.) Irrigated with Treated Wastewater and Groundwater
by
Fayza Kouadri
Microbiol. Res. 2024, 15(3), 1163-1177; https://doi.org/10.3390/microbiolres15030078 - 2 Jul 2024
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Water scarcity is a major agricultural issue in most arid and semi-arid regions of the world. Alternative water supplies, such as the reuse of wastewater for agricultural irrigation, have been introduced. However, little is known about their impact on the soil and rhizosphere
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Water scarcity is a major agricultural issue in most arid and semi-arid regions of the world. Alternative water supplies, such as the reuse of wastewater for agricultural irrigation, have been introduced. However, little is known about their impact on the soil and rhizosphere microbiomes that receive irrigation. Therefore, this work evaluates the impact of treated wastewater (TWW) irrigation on the soil and rhizosphere bacterial communities of date palms in Al Madinah, Saudi Arabia. In this study, metagenomic DNA from the rhizosphere of the date palm was sequenced using Illumina high-throughput sequencing. According to the observed OTUs, Chao1 richness estimations, and Shannon diversity values, soils from groundwater-irrigated date palms showed higher microbial diversity than did soils from TWW-irrigated date palms. A total of 569 OTUs were generated; most of them (97.3%) were assigned into 15 different phyla, whereas 2.7% were marked as unclassified. DNA sequence analysis of the WWT-irrigated rhizosphere showed that the most abundant phyla were Firmicutes (43.6%), Bacteroidetes (17.3%), Proteobacteria (15.2%), and Actinobacteria (14.6%), representing more than 90.7% of the total community, while the soil of the rhizosphere irrigated with GW was dominated by Actinobacteria (44.1%), Proteobacteria (23.4%), Firmicutes (15.5%), and Gemmatimonadetes (4.9%). The most frequently observed species in the two soils were also different. The dominant species in TWW-irrigated soil was Planococcus plakortidis, which is prevalent in saline and moderately saline habitats and can play an important ecological role. The GW-irrigated rhizosphere exhibited higher levels of biocontrol bacteria, particularly Nocardioides mesophilus. These results provide a comprehensive understanding and insights into the population dynamics and microbiome of date palm rhizosphere. The findings show that the irrigation water quality has a significant impact on the microbiome composition. Identifying the microbial diversity is the first step toward determining the best way to use TWW in irrigation.
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Open AccessArticle
Plant Growth-Promoting and Tequila Vinasse-Resistant Bacterial Strains
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Alberto J. Valencia-Botín, Ismael F. Chávez-Díaz, Florentina Zurita-Martínez, Allan Tejeda-Ortega and Lily X. Zelaya-Molina
Microbiol. Res. 2024, 15(3), 1144-1162; https://doi.org/10.3390/microbiolres15030077 - 2 Jul 2024
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Tequila vinasse, a byproduct of the tequila industry, is frequently discharged into water bodies or agricultural fields, posing significant ecological and human health risks. Bacterial communities that inhabit these agricultural fields have developed mechanisms to utilize tequila vinasse as a potential nutrient source
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Tequila vinasse, a byproduct of the tequila industry, is frequently discharged into water bodies or agricultural fields, posing significant ecological and human health risks. Bacterial communities that inhabit these agricultural fields have developed mechanisms to utilize tequila vinasse as a potential nutrient source and to promote plant growth. In this study, strains from the phyla Actinomycetota and Pseudomonadota were isolated from agricultural fields irrigated with tequila vinasse for 2, 10, and 14 years in Jalisco, Mexico. The results showed that strains of Terrabacter, Azotobacter, Agromyces, Prescottella, and Leifsonia tolerate high concentrations of tequila vinasse and promote maize seedling growth in the presence of tequila vinasse. Additionally, some of the strains solubilize potassium and produce siderophores, cellulase, protease, lipase, and esterase. The strains Terrabacter sp. WCNS1C, Azotobacter sp. WCNS1D, and Azotobacter sp. WCNS2A have potential applications in the bioremediation of tequila vinasse in agricultural fields discharged with tequila vinasse.
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Open AccessBrief Report
Factors Influencing Central Venous Catheter-Associated Bloodstream Infections in COVID-19 Patients
by
Adriana Lemos de Sousa Neto, Thalita Campos, Clesnan Mendes-Rodrigues, Reginaldo dos Santos Pedroso and Denise Von Dolinger de Brito Röder
Microbiol. Res. 2024, 15(3), 1134-1143; https://doi.org/10.3390/microbiolres15030076 - 2 Jul 2024
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During the pandemic of COVID-19, the rates of bloodstream infection associated with venous catheter in patients infected with the disease admitted to an intensive care unit rose significantly. In this study, we evaluated the occurrence of bloodstream infections in patients with SARS-CoV-2 and
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During the pandemic of COVID-19, the rates of bloodstream infection associated with venous catheter in patients infected with the disease admitted to an intensive care unit rose significantly. In this study, we evaluated the occurrence of bloodstream infections in patients with SARS-CoV-2 and the variables that made the patients more susceptible to the catheter-associated bloodstream infection (CABSI). Blood culture results from patients interned between March 2020 and December 2021 (n= 109) were collected electronically from the hospital information system and then analyzed. The following variables presented statistical relevance after an adjusted model as follows: obesity (p = 0.003) and time of use of catheter before infection (p = 0.019). In conclusion, patients with shorter catheter use time and obesity had higher incidence of CABSI.
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Open AccessArticle
Characterization of Extended-Spectrum β-Lactamase Producing- and Carbapenem–Resistant Escherichia coli Isolated from Diarrheic Dogs in Tunisia: First Report of blaIMP Gene in Companion Animals
by
Asma Ben Haj Yahia, Ghassan Tayh, Sarrah Landolsi, Ala Maazaoui, Faten Ben Chehida, Aymen Mamlouk, Monia Dâaloul-Jedidi and Lilia Messadi
Microbiol. Res. 2024, 15(3), 1119-1133; https://doi.org/10.3390/microbiolres15030075 - 30 Jun 2024
Abstract
Escherichia coli is an important opportunistic pathogen, causing several infections in dogs. The antimicrobial resistance of E. coli occurring in companion animals becomes an emerging problem. This study aimed to estimate the prevalence of ESBL-producing E. coli in diarrheic dogs, investigate the occurrence
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Escherichia coli is an important opportunistic pathogen, causing several infections in dogs. The antimicrobial resistance of E. coli occurring in companion animals becomes an emerging problem. This study aimed to estimate the prevalence of ESBL-producing E. coli in diarrheic dogs, investigate the occurrence and molecular characterization of carbapenem-resistant isolates, and determine their virulence genes. Fecal samples were collected from 150 diarrheic dogs in Tunisia. E. coli isolates were screened for antimicrobial resistance against 21 antibiotics by the disk diffusion method. The characterization of β-lactamase genes, associated resistance genes, and virulence genes was studied using PCR. Among 95 E. coli strains, 25 were ESBL-producing, and most of them were multidrug-resistant. The most prevalent β-lactamase genes were blaCTX-M1 (n = 14), blaTEM (n = 3), and blaCMY (n = 2). The blaIMP carbapenemase gene was found in two carbapenem-resistant isolates, which showed that carbapenemase-producing E. coli spread to companion animals in Tunisia. Different virulence genes associated with extraintestinal pathogenic E. coli were detected. This is the first report of the characterization of carbapenem resistance and virulence genes in dogs in North Africa. Our study showed that diarrheic dogs in Tunisia can be a potential reservoir of ESBL- or carbapenemase-producing E. coli with a possible risk of transmission to humans.
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(This article belongs to the Special Issue Zoonotic Bacteria: Infection, Pathogenesis and Drugs)
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Open AccessCommunication
Clonality Analysis of Streptococcus pneumoniae in Clinical Specimens
by
Delly Chipta Lestari, Pranee Somboonthum, Daisuke Motooka, Eiji Ishii, Shigeaki Matsuda, Anis Karuniawati and Tetsuya Iida
Microbiol. Res. 2024, 15(3), 1110-1118; https://doi.org/10.3390/microbiolres15030074 - 29 Jun 2024
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Pneumococcal pneumonia is a significant cause of illness and death globally, particularly among young children and the elderly. The cpsB gene is involved in the biosynthesis of the capsule polysaccharide, and polymorphisms in the cpsB gene are the basis for sequetyping, a molecular
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Pneumococcal pneumonia is a significant cause of illness and death globally, particularly among young children and the elderly. The cpsB gene is involved in the biosynthesis of the capsule polysaccharide, and polymorphisms in the cpsB gene are the basis for sequetyping, a molecular biology-based approach to serotyping. In this study, we attempted the sequetyping of pneumococci directly from clinical sputum specimens collected from adult patients diagnosed with community-acquired pneumonia (CAP). We performed conventional PCR for the cpsB gene, followed by TA cloning and Sanger sequencing of the amplicon. The results showed the status of clonality of pneumococci in each specimen. We also performed real-time PCR targeting pneumococci for each specimen. It revealed a significant association between the Ct value of the real-time PCR and the clonality status of pneumococci among the specimens (p-value 0.0007 by Fisher’s exact test analysis). Specifically, when the Ct value was below 22, there was a high probability that pneumococcus existed as a single clone. Thus, this study demonstrates the possible correlation between pneumococcal clonality and bacterial load in clinical specimens, which might indicate the infection status.
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Open AccessCommunication
Effect of Buffer Room Configuration on Isolation of Bacteriophage phi6 and Micrococcus Luteus Emissions
by
Radosław Wróbel, Monika Andrych-Zalewska, Jędrzej Matla, Justyna Molska, Gustaw Sierzputowski, Agnieszka Szulak, Radosław Włostowski, Adriana Włóka and Małgorzata Rutkowska-Gorczyca
Microbiol. Res. 2024, 15(3), 1099-1109; https://doi.org/10.3390/microbiolres15030073 - 27 Jun 2024
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In light of the growing need to mitigate viral infections, such as SARS-CoV-2, which has caused over 770 million infections and 7 million deaths worldwide, the role of architectural design in reducing pathogen spread has become paramount. This study explores how different buffer
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In light of the growing need to mitigate viral infections, such as SARS-CoV-2, which has caused over 770 million infections and 7 million deaths worldwide, the role of architectural design in reducing pathogen spread has become paramount. This study explores how different buffer room configurations impact microbial isolation using the bacterium Micrococcus luteus and bacteriophage phi6 as test organisms. Through a comprehensive approach integrating architecture, technology, and scientific methodologies, we developed strategies to optimise safe buffer environments. Comparative analyses of various isolation systems highlighted significant variations in their effectiveness at reducing bioaerosol concentrations, directly influenced by the design and layout of buffer rooms. These findings are crucial for the effective design of medical and public spaces, particularly during pandemics, where preventing virus transmission is critical for public health.
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Open AccessArticle
First Seroepidemiological Study of Toxoplasma gondii Infection in Dromedaries (Camelus dromedarius) in Southern Tunisia
by
Afef Jeljli, Syrine Rekik, Boubaker Ben Smida, Walid Chandoul, Limam Sassi and Mohamed Gharbi
Microbiol. Res. 2024, 15(3), 1091-1098; https://doi.org/10.3390/microbiolres15030072 - 25 Jun 2024
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Toxoplasma gondii is one of the most common zoonotic parasites worldwide, with infections in humans as well as in all mammals, including dromedaries, that affect reproductive health, leading to malformations and abortions. In the current study, we estimated, for the first time in
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Toxoplasma gondii is one of the most common zoonotic parasites worldwide, with infections in humans as well as in all mammals, including dromedaries, that affect reproductive health, leading to malformations and abortions. In the current study, we estimated, for the first time in Tunisia, the seroprevalence of T. gondii antibodies and its associated risk factors in dromedaries (Camelus dromedarius) using the enzyme-linked immunosorbent assay (ELISA) technique. A total of 248 sera samples were collected from dromedaries living in Médenine and Tataouine governorates, South Tunisia. The overall seroprevalence of T. gondii was estimated to be 29.8 ± 2.9% (74/248) with a significantly higher seroprevalence rate in dromedaries from Médenine (52.5 ± 7.9%; 21/40) compared to Tataouine (25.5 ± 3%; 53/208); it was also higher in dromedaries kept in intensive farming systems (55 ± 11.1%; 11/20) compared to extensive systems (27.6 ± 3%; 63/228), in non-pregnant females (39 ± 4%; 57/146) compared to pregnant ones (16.7 ± 3.7%; 17/102), and in those in contact with cats (66.7 ± 8.6%; 20/30) compared to those with no contact with cats (24.8 ± 2.9%; 54/218). The present study should be followed by others to explore the role of dromedaries in the epidemiological cycle of T. gondii in Southern Tunisia.
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