Microbiology Research

21 pages, 3346 KiB

Open AccessReview

The Genus Clonostachys (Bionectria) as a Potential Tool Against Agricultural Pest and Other Biotechnological Applications: A Review

by Manuela Reyes-Estebanez and Pedro Mendoza-de Gives

Microbiol. Res. 2025, 16(4), 86; https://doi.org/10.3390/microbiolres16040086 - 19 Apr 2025

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Abstract

The Clonostachys genus is a saprophytic soil microfungus (Ascomycota). It exhibits significant ecological adaptability and plays a crucial role in maintaining the balance of soil microorganisms. Species within this genus are natural antagonists of insects and nematodes, and they also combat phytopathogenic fungi [...] Read more.

The Clonostachys genus is a saprophytic soil microfungus (Ascomycota). It exhibits significant ecological adaptability and plays a crucial role in maintaining the balance of soil microorganisms. Species within this genus are natural antagonists of insects and nematodes, and they also combat phytopathogenic fungi through mycoparasitism. This process involves producing lytic enzymes and competing for space and nutrients. Clonostachys species are effective biocontrol agents in agriculture and have been utilized to manage pests affecting many high-value commercial crops, acting as a natural biopesticide. They inhabit plant tissues, boosting plant defenses and activating genes for water and nutrient uptake, enhancing plant performance. Additionally, they produce enzymes and bioactive metabolites with antimicrobial, antifungal, nematocidal, anticancer, and antioxidant properties. Clonostachys species can degrade plastic waste and remove hydrocarbons from crude oil-contaminated sites when functioning as endophytes, positioning Clonostachys as a promising candidate for reducing environmental pollution. There are still challenges and limitations, such as the continuous surveillance of the safety of Clonostachys species on plants, the establishment of commercial applications, formulation viability, and variability due to field conditions. These issues will have to be addressed. This review provides an overview of Clonostachys ecology, morphology, classification, and biotechnological applications, emphasizing its significance in various fields. Full article

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17 pages, 883 KiB

Open AccessReview

The Complexities of Canine Monocytic Ehrlichiosis: Insights into Ehrlichia canis and Its Vector Rhipicephalus sanguineus

by Joana Ferrolho, Sandra Antunes, Hugo Vilhena, Sofia Anastácio, Sérgio Ramalho de Sousa, Gonçalo Frouco, Bárbara Ferreira and Ana Domingos

Microbiol. Res. 2025, 16(4), 85; https://doi.org/10.3390/microbiolres16040085 - 17 Apr 2025

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Abstract

Canine monocytic ehrlichiosis (CME) is a highly infectious disease with zoonotic potential. Ehrlichia canis, the causative agent, is primarily transmitted by Rhipicephalus sanguineus. Tick infestation and tick-borne diseases (TBDs) are serious human and veterinary health problems due to the lack of [...] Read more.

Canine monocytic ehrlichiosis (CME) is a highly infectious disease with zoonotic potential. Ehrlichia canis, the causative agent, is primarily transmitted by Rhipicephalus sanguineus. Tick infestation and tick-borne diseases (TBDs) are serious human and veterinary health problems due to the lack of efficient control measures. This review aims to provide information about CME, detailing epidemiology, pathogenesis, clinical manifestations, and current strategies for diagnosis, treatment, and prevention. The review delves into the biology of R. sanguineus, exploring its lifecycle, habitat, and mechanisms of E. canis transmission. Ehrlichia canis infection follows a three-phase transition: acute, subclinical, and chronic, with distinct clinical signs, from mild to severe and even life-threatening in some cases, with the potential for asymptomatic long-term carriers acting as reservoirs. Pathogenesis involves complex interactions between the pathogen and host immune responses, influencing disease severity and progression. Additionally, the review highlights challenges in controlling CME due to the widespread distribution of R. sanguineus. Genetic diversity within R. sanguineus populations and their varying vector competence further complicate control efforts. The role of environmental changes in tick distribution aligns the control of CME within the One Health concept, integrating approaches to improve outcomes for humans, animals, and the environment. Preventive measures on tick control and potential vaccine development are also reviewed. Full article

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13 pages, 1462 KiB

Open AccessArticle

YKL-40 and Lysosome-Associated Membrane Proteins as Potential Discriminative Biomarkers in Central Nervous System Infections

by Maria Kazakova, Yordan Kalchev, Valentin Dichev, Petya Argirova, Kiril Simitchiev, Mariana Murdjeva and Victoria Sarafian

Microbiol. Res. 2025, 16(4), 84; https://doi.org/10.3390/microbiolres16040084 - 11 Apr 2025

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Abstract

The aim of our study was to evaluate the discriminative value of gene and protein expression levels of the inflammatory marker (YKL-40) and lysosome-associated membrane protein 1 and 2 (LAMP-1 and LAMP-2) in patients with central nervous system (CNS) infections. Thirty hospitalized patients [...] Read more.

The aim of our study was to evaluate the discriminative value of gene and protein expression levels of the inflammatory marker (YKL-40) and lysosome-associated membrane protein 1 and 2 (LAMP-1 and LAMP-2) in patients with central nervous system (CNS) infections. Thirty hospitalized patients with CNS infections and undefined etiology, and 22 healthy subjects as a control group, were included in the study. Gene expression levels of YKL-40, LAMP-1 and LAMP-2 were determined by qPCR. Plasma and CSF concentrations of the tree proteins of interest were detected by ELISA. Our results showed that mRNA levels of YKL-40 were significantly downregulated in WBCs of patients compared to controls, while plasma YKL-40 concentrations were higher. LAMP-1 significantly increased in patients’ plasma and CSF was found. Patients were subdivided depending on the confirmed or presumed etiological agent into two subgroups groups—patients with bacterial or with viral neuroinfection. Differences between plasma levels of YKL-40 in the subgroups when matched with controls were detected. The concentrations of the glycoprotein were higher in patients with bacterial infections compared to those with the viral ones. We revealed that LAMP-1 plasma levels were also significantly increased in patients with viral infections in comparison to healthy individuals. We could speculate that YKL-40 plasma levels might serve as a fast discriminative tool to support the presence of viral or bacterial CNS infections. Full article

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14 pages, 2912 KiB

Open AccessArticle

Antimicrobial Resistance in Swine and Cattle Farms

by Bruna F. Pinto, Sara A. M. Silva, Inês C. Rodrigues, J. M. Lopes-Jorge, J. Niza-Ribeiro, Joana C. Prata and Paulo Martins da Costa

Microbiol. Res. 2025, 16(4), 83; https://doi.org/10.3390/microbiolres16040083 - 9 Apr 2025

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Abstract

Antimicrobial resistance is increasingly becoming a serious public health issue. There is scientific evidence linking the use of antibiotics in livestock production to the emergence and spread of resistance in bacteria that are important for human health. To assess the prevalence of antimicrobial [...] Read more.

Antimicrobial resistance is increasingly becoming a serious public health issue. There is scientific evidence linking the use of antibiotics in livestock production to the emergence and spread of resistance in bacteria that are important for human health. To assess the prevalence of antimicrobial resistance in Escherichia coli and Enterococcus spp., fecal and slurry wastewater samples were collected from various cattle and swine farms, mainly located in the northern and central regions of Portugal. Samples from each farm were pooled for microbiological processing to isolate Escherichia coli and Enterococcus spp., followed by specific antibiotic susceptibility testing for each species using the disk diffusion method. The results of these analyses indicated a significant issue with tetracycline resistance in E. coli and Enterococcus spp. Furthermore, a notably higher frequency in resistant strains was observed in the majority of slurry samples compared to those derived from swine feces. This observation led to the hypothesis that slurry may provide a comprehensive historical perspective for studying the antibiotic resistance patterns present on a farm. Full article

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12 pages, 1180 KiB

Open AccessArticle

Epidemiological, Clinical and Phylogenetic Characteristics of West Nile Virus in Bulgaria, 2024

by Kim Ngoc, Ivan Stoikov, Ivelina Trifonova, Elitsa Panayotova, Iva Trifonova and Iva Christova

Microbiol. Res. 2025, 16(4), 82; https://doi.org/10.3390/microbiolres16040082 - 4 Apr 2025

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Abstract

West Nile Virus (WNV), a mosquito-borne pathogen, is a growing public health challenge across Europe. Environmental and anthropogenic factors have led to the spread of the virus to higher geographic latitudes, as well as to increased viral circulation and genetic diversity. Aims: This [...] Read more.

West Nile Virus (WNV), a mosquito-borne pathogen, is a growing public health challenge across Europe. Environmental and anthropogenic factors have led to the spread of the virus to higher geographic latitudes, as well as to increased viral circulation and genetic diversity. Aims: This study aimed to describe the epidemiological, clinical, and laboratory characteristics of WNV cases in Bulgaria during 2024 and to investigate WNV phylogenetics. Epidemiological, clinical and laboratory data from 32 patients with confirmed or probable WNV infections were collected and analysed. Complete viral genomes were obtained from two samples using whole genome sequencing (WGS). Phylogenetic analysis was performed using the Nextstrain WNV analysis pipeline. Severe disease was observed in 21 patients, with three fatalities reported in older males with comorbidities. Phylogenetic analysis revealed that Bulgarian strains clustered within the Central/Southern European clade of lineage 2, closely related to Greek strains. Evidence suggested localised viral evolution following cross-border introduction from Greece. Our study provides a detailed clinical and laboratory characterization of the human WNV cases detected in Bulgaria in 2024. Improved diagnostic workflows, expanded laboratory resources and increased molecular surveillance are essential to better understand the burden of WNV infections in Bulgaria, as well as to follow the evolution and spread of the virus. Full article

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15 pages, 2612 KiB

Open AccessArticle

Molecular and Epidemiological Analysis of Carbapenem-Resistant Klebsiella pneumoniae in a Greek Tertiary Hospital: A Retrospective Study

by Alexandra Myari, Petros Bozidis, Efthalia Priavali, Eleni Kapsali, Vasilios Koulouras, Georgia Vrioni and Konstantina Gartzonika

Microbiol. Res. 2025, 16(4), 81; https://doi.org/10.3390/microbiolres16040081 - 4 Apr 2025

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Abstract

Carbapenemase-producing Klebsiella pneumoniae is responsible for multiple serious infections with high mortality rates. K. pneumoniae carbapenemases (KPCs) are the most commonly isolated carbapenemases worldwide. To study the epidemiological and molecular characteristics of KPC-producing K. pneumoniae (KPC-KP), we conducted a retrospective study at the [...] Read more.

Carbapenemase-producing Klebsiella pneumoniae is responsible for multiple serious infections with high mortality rates. K. pneumoniae carbapenemases (KPCs) are the most commonly isolated carbapenemases worldwide. To study the epidemiological and molecular characteristics of KPC-producing K. pneumoniae (KPC-KP), we conducted a retrospective study at the University General Hospital of Ioannina, Greece. A total of 177 K. pneumoniae clinical strains from the period 2014–2015 were confirmed as KPC producers by polymerase chain reaction (PCR) and were further examined for the presence of bla_VIM, bla_NDM, bla_TEM, bla_SHV, and bla_CTX-M genes. Using the amplification refractory mutation system (ARMS) method, we identified the presence of the KPC-2 allele in 130 strains and the KPC-9 allele in 47. Strains from both allele groups belonged to the sequence type 258 (ST258). KPC-9 was responsible for a distinct outbreak, considered part of the broader KPC-2 outbreak. Molecular characterization of selected KPC-KP isolates from the period 2021–2022 revealed their continued presence in our hospital. Comparison of the antimicrobial susceptibility profiles of the two alleles showed a statistically significant increase in minimum inhibitory concentration (MIC) for ceftazidime (p = 0.03) and higher resistance to amikacin (p = 0.012) and colistin (p < 0.001) for KPC-9 compared to the KPC-2 allele. The two KPC alleles had similar mortality rates. This study demonstrates the heterogeneity of resistance genes in carbapenem-resistant K. pneumoniae (CR-KP) within a single-hospital setting and underscores the need for immediate containment measures. Full article

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16 pages, 1659 KiB

Open AccessArticle

Enhancing Diagnostic Resilience: Evaluation of Extraction Platforms and IndiMag Pathogen Kits for Rapid Animal Disease Detection

by Anne Vandenburg-Carroll, Douglas G. Marthaler and Ailam Lim

Microbiol. Res. 2025, 16(4), 80; https://doi.org/10.3390/microbiolres16040080 - 3 Apr 2025

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Abstract

The United States is facing outbreaks of highly pathogenic avian influenza H5N1 in birds and dairy cattle, along with threats of African swine fever, classical swine fever, and foot-and-mouth disease. While the National Animal Health Laboratory Network (NAHLN) depends on high-throughput testing, the [...] Read more.

The United States is facing outbreaks of highly pathogenic avian influenza H5N1 in birds and dairy cattle, along with threats of African swine fever, classical swine fever, and foot-and-mouth disease. While the National Animal Health Laboratory Network (NAHLN) depends on high-throughput testing, the KingFisher Duo Prime, IndiMag 48s, and IndiMag 2 are viable alternatives to aid in outbreak assessments. This study evaluates extraction platforms and the IndiMag Pathogen Kit for detecting the previous listed pathogens. Samples and reference materials were extracted using the MagMAX Viral RNA Isolation Kit, MagMAX CORE Nucleic Acid Purification Kit, and IndiMag Pathogen Kit. Real-time RT-PCR was performed following NAHLN protocols to assess analytical and diagnostic performance. Comparable limits of detection across extraction chemistries, instrumentation, and pathogens were demonstrated, with PCR efficiency ranging between 82.5% and 107.6%. The precision variability was low, with the coefficient of variation ranging from 0.16% to 1.76%. Diagnostic sensitivity and specificity were 100%, with a kappa coefficient of 1.0, indicating strong agreement between methods. These findings support the KingFisher Duo Prime, IndiMag 48s, IndiMag 2, and IndiMag Pathogen Kits as reliable options for NAHLN-approved testing, increasing equipment and reagent alternatives to enhance diagnostic resilience and improve response capabilities to emerging animal health threats. Full article

(This article belongs to the Special Issue Veterinary Microbiology and Diagnostics)

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14 pages, 1578 KiB

Open AccessArticle

Bacterial Profile and Antimicrobial Resistance Pattern from Different Clinical Specimens at Uttara Adhunik Medical College Hospital, Dhaka

by Mahfuza Nasrin, Fahmida Begum, Mohammad Julhas Sujan, Hridika Talukder Barua, Zakir Hossain Habib, S M Shahriar Rizvi, Aninda Rahman, Alina Shaw, Abul Hasnat, Soo Young Kwon, Rezina Karim, Md. Shah Alam, Noshin Nawal, Mohammad Moniruzzaman Bhuiyan, Ahmed Taha Aboushady, Adam Clark, John Stelling, Sanjay Gautam, Florian Marks and Nimesh Poudyal

Microbiol. Res. 2025, 16(4), 79; https://doi.org/10.3390/microbiolres16040079 - 2 Apr 2025

Viewed by 273

Abstract

Introduction: Antimicrobial resistance (AMR) is a critical global public health issue, leading to prolonged illness, increased morbidity and mortality, and rising healthcare costs. The effectiveness of antibiotics is diminishing due to the emergence of resistant bacterial strains. This study aimed to determine the [...] Read more.

Introduction: Antimicrobial resistance (AMR) is a critical global public health issue, leading to prolonged illness, increased morbidity and mortality, and rising healthcare costs. The effectiveness of antibiotics is diminishing due to the emergence of resistant bacterial strains. This study aimed to determine the bacterial profile and AMR patterns of clinical isolates at Uttara Adhunik Medical College Hospital (UAMCH), Dhaka. Methods: A retrospective study was conducted at UAMCH from January 2017 to December 2019. A total of 32,187 clinical specimens (urine, blood, stool, wound swabs/pus, and sputum) were processed, of which 4232 yielded positive cultures. Bacterial identification followed standard bacteriological methods, and antibiotic susceptibility was assessed using the Kirby–Bauer disc diffusion method per CLSI guidelines. Data analysis was conducted using WHONET and QAAPT. Results: The highest proportion of positive cultures was from urine (47.5%), followed by blood (35.0%) and wound swabs/pus (10.1%). The most common isolates were Escherichia coli (37.2%), Salmonella typhi (25.7%), and Klebsiella sp. (11.5%). Gram-negative bacteria showed high resistance to commonly used antibiotics such as amoxicillin/clavulanic acid, cefixime, and ceftriaxone, while the resistance rates were lower for gentamicin, amikacin, and meropenem. However, Acinetobacter sp. exhibited alarming resistance to all tested antibiotics. Conclusions: This study highlights concerning resistance patterns among bacterial isolates, emphasizing the need for ongoing AMR surveillance to inform treatment strategies and improve patient care in Bangladesh. Full article

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23 pages, 3863 KiB

Open AccessReview

Bacterial Foodborne Diseases in Central America and the Caribbean: A Systematic Review

by Nicole Severino, Claudia Reyes, Yumeris Fernandez, Vasco Azevedo, Luis Enrique De Francisco, Rommel T. Ramos, Luis Orlando Maroto-Martín and Edian F. Franco

Microbiol. Res. 2025, 16(4), 78; https://doi.org/10.3390/microbiolres16040078 - 1 Apr 2025

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Abstract

Foodborne diseases (FBDs) represent a significant public health concern, particularly in regions like Central America and the Caribbean (CAC), where surveillance gaps due to a lack of resources, knowledge, and technical abilities hinder control over outbreaks. This review investigates the bacterial pathogens responsible [...] Read more.

Foodborne diseases (FBDs) represent a significant public health concern, particularly in regions like Central America and the Caribbean (CAC), where surveillance gaps due to a lack of resources, knowledge, and technical abilities hinder control over outbreaks. This review investigates the bacterial pathogens responsible for FBDs, their prevalence, management challenges, and prevention strategies. This systematic review followed PRISMA guidelines, focusing on bacterial FBDs in CAC from 2000 to 2024. PubMed and Google Scholar were used as primary databases, supported by other sources to identify relevant studies. Inclusion criteria encompassed studies focusing on bacterial pathogens, prevalence, risk factors, and surveillance practices. Out of the 509 studies initially identified, 35 met the inclusion criteria. The most prevalent pathogens were Salmonella spp., Escherichia coli, Campylobacter spp., and Aliarcobacter spp., with contamination often associated with poultry, eggs, and vegetables. Key challenges included inadequate surveillance systems, limited resources, and inconsistent reporting practices. A more significant investment in pathogen monitoring, documentation, and education, along with technologies like whole-genome sequencing (WGS), is crucial. Institutional and governmental funding is vital to improve surveillance and strengthen regional risk analysis. Full article

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13 pages, 3458 KiB

Open AccessArticle

Antiprotozoal Activity and Selectivity Index of Organic Salts of Albendazole and Mebendazole

by Miriam Guadalupe Barón-Pichardo, Janeth Gómez-García, David Durán-Martínez, Oscar Torres-Angeles, Jesús Rivera-Islas and Blanca Estela Duque-Montaño

Microbiol. Res. 2025, 16(4), 77; https://doi.org/10.3390/microbiolres16040077 - 27 Mar 2025

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Abstract

Infections from the protozoa Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), and Trichomonas vaginalis (T. vaginalis) pose a public health issue, with albendazole and mebendazole serving as the second-line medications for treating these parasitic infections. However, [...] Read more.

Infections from the protozoa Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), and Trichomonas vaginalis (T. vaginalis) pose a public health issue, with albendazole and mebendazole serving as the second-line medications for treating these parasitic infections. However, the low aqueous solubility of these compounds has led to the exploration of new strategies to enhance their solubility, with the formation of salts being a commonly employed strategy. The sulfonates A1, A2, and A3 of albendazole, along with M1, M2, and M3 of mebendazole, were synthesized. The antiparasitic activity in vitro was assessed against the trophozoites of E. histolytica, G. lamblia, and T. vaginalis. The salts A2, A3, M2, and M3 demonstrated a greater antiparasitic effect (IC₅₀ 37.95–125.53 µM) compared to the positive controls albendazole and mebendazole. The salts A1, A3, M2, and M3 do not exhibit cytotoxic effects at concentrations of 500 µM on the Vero cell line. Taken together, these findings indicate that the formation of these new solid saline phases enhances the antiparasitic effects in vitro, which is crucial in the current search for improved, safe, and effective antiparasitic agents. Full article

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17 pages, 582 KiB

Open AccessReview

Rabbit Models for Infectious Diseases Caused by Staphylococcus aureus

by Minghang Zeng, Yadong Wang, Fang Liu, Jinzhao Long and Haiyan Yang

Microbiol. Res. 2025, 16(4), 76; https://doi.org/10.3390/microbiolres16040076 - 27 Mar 2025

Viewed by 278

Abstract

Staphylococcus aureus (S. aureus) is a disreputable symbiotic bacterium that is responsible for a range of diseases, including life-threatening pneumonia, endocarditis, septicemia, and others, which has led to an immense loss in both public health and economy, imposing a significant burden [...] Read more.

Staphylococcus aureus (S. aureus) is a disreputable symbiotic bacterium that is responsible for a range of diseases, including life-threatening pneumonia, endocarditis, septicemia, and others, which has led to an immense loss in both public health and economy, imposing a significant burden on society. To investigate the pathogenic mechanism of S. aureus and develop new treatment methods for infectious diseases caused by S. aureus, various rabbit models have been developed to simulate different infections by S. aureus, such as pneumonia models, meningitis models, and endocarditis models, etc. In this review, we summarized the application of rabbit models in S. aureus-induced infectious diseases. Full article

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37 pages, 2942 KiB

Open AccessReview

The Role of Microbial Dynamics, Sensorial Compounds, and Producing Regions in Cocoa Fermentation

by Sofia de M. Campos, Walter J. Martínez-Burgos, Guilherme Anacleto dos Reis, Diego Yamir Ocán-Torres, Gabriela dos Santos Costa, Fernando Rosas Vega, Beatriz Alvarez Badel, Liliana Sotelo Coronado, Josilene Lima Serra and Carlos Ricardo Soccol

Microbiol. Res. 2025, 16(4), 75; https://doi.org/10.3390/microbiolres16040075 - 26 Mar 2025

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Abstract

Cocoa fermentation is a critical step in chocolate production, influencing the flavor, aroma, and overall quality of the final product. This review focuses on the microbial dynamics of cocoa fermentation, emphasizing the roles of yeasts, lactic acid bacteria (LAB), and acetic acid bacteria [...] Read more.

Cocoa fermentation is a critical step in chocolate production, influencing the flavor, aroma, and overall quality of the final product. This review focuses on the microbial dynamics of cocoa fermentation, emphasizing the roles of yeasts, lactic acid bacteria (LAB), and acetic acid bacteria (AAB). These microorganisms interact in a well-defined succession, producing organoleptic compounds such as alcohols, organic acids, and esters, which are key to the sensory profile of cocoa. This article examines the impact of different fermentation methods, including spontaneous fermentation and the use of starter cultures, on microbial communities and flavor development. Advances in starter culture technology are highlighted, demonstrating how microbial control can enhance fermentation efficiency, reduce fermentation time, and improve the consistency of chocolate flavor. Patents related to cocoa fermentation further emphasize the growing interest in microbial management to meet market demands for high-quality, distinct chocolate. This review also outlines future research directions, including the identification of new microbial strains, optimization of fermentation conditions, and the potential of biotechnological advancements to improve the fermentation process. Understanding microbial dynamics in cocoa fermentation offers significant potential for enhancing chocolate quality, sustainability, and the development of new, region-specific flavor profiles. Full article

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14 pages, 10950 KiB

Open AccessArticle

Frequency, Resistance Patterns, and Serotypes of Salmonella Identified in Samples from Pigs of Colombia Collected from 2022 to 2023

by Stefany Barrientos-Villegas, Juana L. Vidal, Nidia Gomez, Fernando L. Leite, Sara López-Osorio and Jenny J. Chaparro-Gutiérrez

Microbiol. Res. 2025, 16(4), 74; https://doi.org/10.3390/microbiolres16040074 - 25 Mar 2025

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Abstract

The objective of this study was to determine the frequency of Salmonella in pig samples analyzed at the Veterinary Diagnostic Unit of the Faculty of Agricultural Sciences of the University of Antioquia, Colombia, between 2022 and 2023. Out of 5820 serum samples analyzed [...] Read more.

The objective of this study was to determine the frequency of Salmonella in pig samples analyzed at the Veterinary Diagnostic Unit of the Faculty of Agricultural Sciences of the University of Antioquia, Colombia, between 2022 and 2023. Out of 5820 serum samples analyzed using indirect enzyme-linked immunosorbent assay, 63.76% were positive. Additionally, Salmonella was isolated and identified in a separate group of 848 samples (feces, tissues, etc.) with a positivity rate of 23.47%. Eight serotypes were identified, with the most common being Salmonella enterica subsp. enterica serotype Typhimurium (49.2%), followed by its monophasic variant I 4,[5],12:i:- (23%), and serotype Choleraesuis (18%). Antimicrobial susceptibility profiles of 105 isolates were evaluated using the Kirby–Bauer method, which demonstrated higher resistance (100%) to ampicillin, tiamulin, penicillin, tylosin, and erythromycin (these were the least tested), followed by florfenicol (44/54), doxycycline (4/5), spectinomycin (18/25), amoxicillin (32/46), chloramphenicol (2/3), tetracycline (2/3), and enrofloxacin (34/64), with lower resistance observed for fosfomycin (2/38) and ceftiofur (5/35). Multi-drug resistance was observed in 59% (62/105) of the isolates. The high proportion of Salmonella and the levels of resistance to various drugs raise significant concerns, indicating potential deficiencies in responsible antimicrobial use and management practices on pig farms in the region. Full article

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13 pages, 434 KiB

Open AccessReview

Molecular Epidemiology and Antimicrobial Resistance in Uropathogenic Escherichia coli in Saudi Arabian Healthcare Facilities

by Mateq Ali Alreshidi

Microbiol. Res. 2025, 16(4), 73; https://doi.org/10.3390/microbiolres16040073 - 22 Mar 2025

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Abstract

Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are a major healthcare challenge, necessitating effective antimicrobial therapy for treatment. However, the prevalence of antimicrobial resistance among UPEC strains is escalating, particularly among patients experiencing recurrent infection. The rise in UPEC strains [...] Read more.

Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) are a major healthcare challenge, necessitating effective antimicrobial therapy for treatment. However, the prevalence of antimicrobial resistance among UPEC strains is escalating, particularly among patients experiencing recurrent infection. The rise in UPEC strains that exhibit resistance to multiple antimicrobial agents, including the spread of extended-spectrum beta-lactamase (ESBL)-producing UPEC, intensifies the complexity of managing UTIs. Genetic variations within UPEC strains play a major role in their ability to resist antimicrobial agents and adapt to changing environments. Unveiling and understanding the genomic landscape of emerging UPEC strains is essential for comprehending the genetic basis of their resilience. Moreover, monitoring these genetic strains is crucial for identifying patterns of resistance dissemination, guiding infection control measures, and informing the development of targeted therapeutics. Full article

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16 pages, 2450 KiB

Open AccessArticle

Inducing and Enhancing Antimicrobial Activity of Mining-Soil-Derived Actinomycetes Through Component Modification of Bennett’s Culture Medium

by Soumia Ait Assou, Jaouad Anissi, Laurent Dufossé, Mireille Fouillaud and Mohammed EL Hassouni

Microbiol. Res. 2025, 16(4), 72; https://doi.org/10.3390/microbiolres16040072 - 22 Mar 2025

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Abstract

This study investigated the effect of different culture agar media, derived from Bennett’s medium, on the antimicrobial activity of 15 Streptomyces sp. and 1 Lentzea sp. strains isolated from mining environments. The media were prepared from the standard Bennett’s medium by suppressing one, [...] Read more.

This study investigated the effect of different culture agar media, derived from Bennett’s medium, on the antimicrobial activity of 15 Streptomyces sp. and 1 Lentzea sp. strains isolated from mining environments. The media were prepared from the standard Bennett’s medium by suppressing one, two, or three ingredients—yeast extract (YE), beef extract (BE), or casein (Cas)—while maintaining glucose (Gluc) or by substituting it with fructose (Fruc) or galactose (Gal) and keeping the same suppressions. The antimicrobial activity was investigated against Candida albicans ATCC 10231, Staphylococcus aureus ATCC 29213, Bacillus subtilis ATCC 6633, and Escherichia coli K12. The antimicrobial activity of actinomycete strains was positively influenced by media modifications, though the response was actinomycete strain and target pathogen-dependent. Unexpectedly, thirteen strains exhibited poor growth on a pure agar-agar medium, including six Streptomyces strains (AS34, AS3, BS59, BS68, BS69, and DAS104) that showed notable antimicrobial activity, with inhibition zone diameters ranging from 10.75 ± 1.06 to 18.00 ± 0.00 mm. Modifications of Bennett’s medium, including replacing glucose with fructose or galactose and maintaining yeast extract or both yeast extract and beef extract, induced and enhanced the antimicrobial activity of several actinomycete strains. Notably, the new media induced antimicrobial activity in strains that showed no activity in Bennett’s medium. They led, compared to Bennett’s medium, to the detection of eight additional active strains against S. aureus, eight against B. subtilis, six against E. coli, and four against C. albicans. This study is the first to explore the modification of Bennett’s medium, either by subtraction or substitution, in order to investigate the effect on antimicrobial activity of actinomycete strains. These results highlight the importance of the composition of culture media on inducing or boosting antimicrobial activity in Streptomyces and Lentzea. Full article

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Microbiol. Res., Volume 16, Issue 4 (April 2025) – 15 articles

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