bluuebunny/crossref_metadata_2025 huggingface dataset:
New Insights into the Antimicrobial Potential of Polyalthia longifolia—Antibiofilm Activity and Synergistic Effect in Combination with Penicillin against Staphylococcus aureus
Authors: Savu Mihaela , Simo Marguerite Kamdem , Fopokam Gabriel Xavier , Olaru Stefan Mihaita , Cioanca Oana , Boyom Fabrice Fekam , Stefan Marius
Published: October 2022

Widespread antibiotic resistance has led to the urgent need for the identification of new antimicrobials. Plants are considered a valuable potential resource for new effective antimicrobial compounds. Therefore, in the present study, we focused on the antimicrobial activity of Polyalthia longifolia plants harvested from Cameroon using the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and time-kill assays. The mechanism of action was investigated by employing fluorescence and scanning electron microscopy. The anti-Staphylococcus aureus activity was studied using biofilm inhibition and checkerboard assays. Our results revealed that the tested extracts possess important antimicrobial activities, notably against Gram positive bacteria (MICs as low as 0.039 mg/mL). P. longifolia leaf extracts exhibited a significant bactericidal effect, with a total kill effect recorded after only 2 h of exposure at concentrations equivalent to MBC (0.078 and 0.156 mg/mL). The extracts showed a synergistic antibacterial activity in combination with penicillin against a MRSA clinical isolate and significantly inhibited S. aureus biofilm formation. The mechanism of action is related to the impairment of cell membrane integrity and cell lysis. All these findings suggest that P. longifolia could be an important source of reliable compounds used to develop new antimicrobials.
The Impact of Latent Toxoplasma gondii Infection on Spontaneous Abortion History and Pregnancy Outcomes: A Large-Scale Study
Authors: Mocanu Adelina Geanina , Stoian Dana Liana , Craciunescu Emanuela Lidia , Ciohat Ioana Mihaela , Motofelea Alexandru Catalin , Navolan Dan Bogdan , Vilibic-Cavlek Tatjana , Stevanovic Vladimir , Nemescu Dragos , Forga Marius , Daniluc Razvan , Ioana Alexandra-Magdalena , Craina Marius
Published: October 2022

Background: Toxoplasma gondii (TG), a zoonotic protozoan parasite, belongs to a group of TORCH infectious agents, which can cause severe damage to the fetus if a primary infection occurs during pregnancy. After primary infection, TG rests lifelong in human organisms causing a latent infection. Most studies have analyzed the consequences of acute, but not latent, TG infection. This study analyzed the impact of latent toxoplasmosis on spontaneous abortion history, pregnancy complication rate and neonatal outcome. Methods: IgG and IgM anti-TG antibodies were tested in 806 pregnant women who were consulted at the Timisoara Clinical Emergency Hospital between 2008 and 2010. Demographic data, obstetrical history, and data about the pregnancy complications, birth and neonate were collected for each woman and comparisons between the groups, with and without latent TG infection, were made. Results: This study did not show differences between groups regarding the history of spontaneous abortion (OR = 1.288, p = 0.333), cesarean section (OR = 1.021, p = 0.884), placental abruption (OR 0.995, p = 0.266), pregnancy-induced hypertension rate (OR 1.083, p = 0.846), secondary sex ratio (1.043, p = 0.776), 1′ APGAR score at birth (p = 0.544), gestational age at birth (p = 0.491) or birth weight (p = 0.257). Conclusions: The observed differences between the rate of pregnancy complications in the two groups of pregnant women with and without latent infection with TG, did not reach a statistical significance.
EbfC/YbaB: A Widely Distributed Nucleoid-Associated Protein in Prokaryotes
Authors: Cordeiro Tamires Fernanda Vilas Boas , Gontijo Marco Túlio Pardini , Jorge Genesy Perez , Brocchi Marcelo
Published: October 2022

Genomic compaction is an essential characteristic of living organisms. Nucleoid-associated proteins (NAPs) are a group of small proteins that play crucial roles in chromosome architecture and affect DNA replication, transcription, and recombination by imposing topological alterations in genomic DNA, thereby modulating global gene expression. EbfC/YbaB was first described as a DNA-binding protein of Borrelia burgdorferi that regulates the expression of surface lipoproteins with roles in virulence. Further studies indicated that this protein binds specifically and non-specifically to DNA and colocalises with nucleoids in this bacterium. The data showed that this protein binds to DNA as a homodimer, although it can form other organised structures. Crystallography analysis indicated that the protein possesses domains responsible for protein–protein interactions and forms a “tweezer” structure probably involved in DNA binding. Moreover, sequence analysis revealed conserved motifs that may be associated with dimerisation. Structural analysis also showed that the tridimensional structure of EbfC/YbaB is highly conserved within the bacterial domain. The DNA-binding activity was observed in different bacterial species, suggesting that this protein can protect DNA during stress conditions. These findings indicate that EbfC/YbaB is a broadly distributed NAP. Here, we present a review of the existing data on this NAP.
Emerging Research Topics in the Vibrionaceae and the Squid–Vibrio Symbiosis
Authors: Soto William
Published: October 2022

The Vibrionaceae encompasses a cosmopolitan group that is mostly aquatic and possesses tremendous metabolic and genetic diversity. Given the importance of this taxon, it deserves continued and deeper research in a multitude of areas. This review outlines emerging topics of interest within the Vibrionaceae. Moreover, previously understudied research areas are highlighted that merit further exploration, including affiliations with marine plants (seagrasses), microbial predators, intracellular niches, and resistance to heavy metal toxicity. Agarases, phototrophy, phage shock protein response, and microbial experimental evolution are also fields discussed. The squid–Vibrio symbiosis is a stellar model system, which can be a useful guiding light on deeper expeditions and voyages traversing these “seas of interest”. Where appropriate, the squid–Vibrio mutualism is mentioned in how it has or could facilitate the illumination of these various subjects. Additional research is warranted on the topics specified herein, since they have critical relevance for biomedical science, pharmaceuticals, and health care. There are also practical applications in agriculture, zymology, food science, and culinary use. The tractability of microbial experimental evolution is explained. Examples are given of how microbial selection studies can be used to examine the roles of chance, contingency, and determinism (natural selection) in shaping Earth’s natural history.
Microencapsulation of Probiotics for Food Functionalization: An Update on Literature Reviews
Authors: Sbehat Maram , Mauriello Gianluigi , Altamimi Mohammad
Published: October 2022

Functional foods comprise the largest growing food category due to both consumer demands and health claims by manufacturers. Probiotics are considered one of the best choices for meeting these demands. Traditionally, the food vehicle for introducing probiotics to consumers was dairy products, and to expand the benefits of probiotics for a wider range of consumers, the need to use other food items was essential. To achieve this goal while maximising the benefits of probiotics, protection methods used during food processing were tackled. The microencapsulation of probiotics is a promising methodology for achieving this function. This review highlights the use of the microencapsulation of probiotics in order to functionalise food items that initially were not considered suitable for probiotication, such as baked products, or to increase their functionality such as dairy products. The co-microencapsulation of probiotics with other functional ingredients such polyphenol, prebiotics, or omega-3 is also highlighted.
Greek Remdesivir Cohort (GREC) Study: Effectiveness of Antiviral Drug Remdesivir in Hospitalized Patients with COVID-19 Pneumonia
Authors: Petrakis Vasilis , Rapti Vasiliki , Akinosoglou Karolina , Bonelis Constantinos , Athanasiou Kalomoira , Dimakopoulou Vasiliki , Syrigos Nikolaos K. , Spernovasilis Nikolaos , Trypsianis Grigoris , Marangos Markos , Gogos Charalambos , Papazoglou Dimitrios , Panagopoulos Periklis , Poulakou Garyfallia
Published: October 2022

In several randomized studies, remdesivir (RDV) has been reported to shorten the recovery period and improve clinical outcomes in COVID-19 patients, and thus, it is recommended as a standard of care. Nevertheless, controversial reports have been published. The aim of the present study is to evaluate the effectiveness of remdesivir in hospitalized patients with COVID-19 pneumonia at three Greek University Departments of Infectious Diseases with homogenous treatment protocols. From September 2020 to February 2021, we retrospectively analyzed adults hospitalized with confirmed SARS-CoV-2 infection and radiological findings of pneumonia, who received remdesivir once daily for five days. Exploratory end points were duration of hospitalization, time of intubation, and death. Overall, 551 patients were included in the study. The optimal cutoff point for the number of days needed after symptom initiation for drug administration associated with better clinical outcome was 7 days. Higher odds for discharge and lower for intubation were observed in patients with treatment initiation ≤7 days (p = 0.052 and p = 0.019, retrospectively) regardless of gender (p = 0.537), hypertension (p = 0.096), dyslipidemia (p = 0.221), diabetes mellitus (p = 0.306), and usage of immunomodulators (p = 0.408). Our study has demonstrated beneficial effects of early treatment with remdesivir (≤7 days from symptom onset) on rates of intubation and probability of discharge.
Response of Carbon Emissions and the Bacterial Community to Freeze–Thaw Cycles in a Permafrost-Affected Forest–Wetland Ecotone in Northeast China
Authors: Liu Chao , Dong Xingfeng , Wu Xiaodong , Ma Dalong , Wu Yufei , Man Haoran , Li Miao , Zang Shuying
Published: October 2022

Climate warming can affect freeze–thaw cycle (FTCs) patterns in northern high-latitude regions and may affect permafrost carbon emissions. The response of carbon release and microbial communities to FTCs has not been well characterized. Here, we conducted laboratory incubation experiments to investigate the relationships among carbon emissions, bacterial community, and soil variables in a permafrost-affected forest–wetland ecotone in Northeast China. The emission rates of CO2 and CH4 increased during the FTCs. FTC amplitude, FTC frequency, and patch type had significant effects on carbon emissions. FTCs increased the contents of soil DOC, NH4+-N, and NO3−-N but reduced bacterial alpha diversity. CO2 emissions were mainly affected by bacterial alpha diversity and composition, and the inorganic nitrogen content was the important factor affecting CH4 emissions. Our findings indicated that FTCs could significantly regulate CO2 and CH4 emissions by reducing bacterial community diversity and increasing the concentration of available soil substrates. Our findings shed new light on the microorganism-substrate mechanisms regulating the response patterns of the soil carbon cycle to FTCs in permafrost regions.
The Hidden World within Plants
Authors: Jeandet Philippe , Lahlali Rachid , Barka Essaid Ait
Published: October 2022

Plants offer an ecosystem for microorganisms from diverse phylogenetic domains and phyla as well as viruses and viroids [...]
First Detection of the SARS-CoV-2 Omicron BA.5/22B in Monaco
Authors: Colson Philippe , Lavagna Christian , Delerce Jérémy , Groshenry Guillaume , Yahi Nouara , Fantini Jacques , La Scola Bernard , Althaus Thomas
Published: October 2022

The Omicron BA.5/22B variant has been designated as a “variant of concern” by the World Health Organization. We describe, here, the first evidence in Monaco of infection with an Omicron BA.5/22B variant, probably imported from the Republic of Seychelles, harboring a rare combination of non-BA.5/22B signature amino acid changes. SARS-CoV-2 neutralizing antibodies were measured with a surrogate virus neutralization test. SARS-CoV-2 genotype screening was performed on nasopharyngeal samples with a multiplex qPCR assay. The SARS-CoV-2 genome was obtained by next-generation sequencing with the Illumina COVID-seq protocol, then assembly using bioinformatics pipelines and software was performed. The BA.5/22B spike protein structure was obtained by molecular modeling. Two spouses were SARS-CoV-2-diagnosed the day they returned from a one-week trip in the Republic of Seychelles. SARS-CoV-2 qPCR screening for variant-specific mutations identified an Omicron variant BA.1/21K, BA.4/22A, or BA.5/22B. A SARS-Co-2 BA.5/22B variant genome was recovered from one of the spouses. Aside from BA.5/22B-defining amino acid substitutions, four other amino acid changes were encoded including Q556K in ORF1a, K2557R in ORF1b, and A67V and A829T in spike; only 13 genomes in sequence databases harbored these four mutations concurrently. Structural analysis of this BA.5/22B variant predicted that A829T in spike may result in a compaction that may affect conformational plasticity. Overall, our findings warrant performing genome-based genotypic surveillance to survey accurately the emergence and circulation of SARS-CoV-2 variants worldwide and point out that their first occurrence in a country is often through international travel despite implemented countermeasures.
‘Candidatus Mycoplasma Haemoalbiventris’ and Tick-Borne Pathogens in Black-Eared Opossum (Didelphis aurita) from Southeastern Brazil
Authors: Orozco Andrés Maurício Ortega , Bento Lucas Drumond , Souto Pollyanna Cordeiro , Girardi Fabricia Modolo , Nogueira Bárbara Cristina Félix , Yamatogi Ricardo Seiti , Campos Artur Kanadani , Cray Carolyn , Montiani-Ferreira Fabiano , Collere Flávia Carolina Meira , Vieira Thállitha Samih Wischral Jayme , Vieira Rafael Felipe da Costa , Fonseca Leandro Abreu da
Published: October 2022

The black-eared opossum (Didelphis aurita) is a South American synanthropic marsupial. The presence of opossums in domestic spaces is relevant in the One-Health context since they are hosts of pathogens and ectoparasites that may affect the health of domestic animals and humans. In this study, we aim to determine the occurrence of hemoplasmas and selected tick-borne pathogens in free-ranging black-eared opossums, along with their molecular characterization, hematological and biochemical evaluation and factors associated with infection, in the municipality of Viçosa, State of Minas Gerais, southeastern Brazil. Thirty black-eared opossums were trapped between March 2021 and June 2022. Ectoparasites were collected. Hematological and biochemical analyses were performed. DNA from EDTA-blood samples were analyzed by PCR and qPCR assays. By molecular analyses, ‘Candidatus Mycoplasma haemoalbiventris’ was the most prevalent hemoparasite (73.3%), followed by Hepatozoon sp. (22.2%). Significant differences were observed in the number of platelets, and in the concentration of protein and globulins in the animals infected by ‘Ca. M. haemoalbiventris’ when compared with the negative group. This is the first report of ‘Ca. M. haemoalbiventris’ infection in D. aurita.
Detection of Tick-Borne Pathogens in Ticks from Cattle in Western Highlands of Cameroon
Authors: Ngnindji-Youdje Yannick , Diarra Adama Zan , Lontsi-Demano Michel , Tchuinkam Timoléon , Parola Philippe
Published: October 2022

This study aimed to detect and identify microorganisms in ticks collected in the Western Highlands of Cameroon. Quantitative real-time and standard PCR assays, coupled with sequencing, were used. A total of 944 ticks collected from cattle in five distinct sites in Cameroon were selected for the analyses. They belonged to five genera (Amblyomma, Hyalomma, Rhipicephalus, Haemaphysalis, and Ixodes) and twelve species. Real-time PCR revealed that 23% (n = 218) of the ticks were positive for Rickettsia spp., 15% (n = 141) for bacteria of the Anaplasmataceae family, 3% (n = 29) for Piroplasmida, 0.5% (n = 5) for Coxiella burnetii, 0.4% (n = 4) for Borrelia spp., and 0.2% (n = 2) for Bartonella spp. The co-infection rate (3.4%, n = 32) involved mainly Rickettsia spp. and Anaplasmataceae. Of the Rickettsia spp. positive ticks, the targeted PCR and sequencing yielded Rickettsia africae (78.9%), Rickettsia aeschlimannii (6.4%), Rickettsia massiliae (7.8%), Candidatus Rickettsia barbariae (0.9%), and Rickettsia sp. (0.9%). Anaplasmataceae included Anaplasma marginale (4.3%), Anaplasma platys (1.4%), Anaplasma centrale (0.7%), Ehrlichia ruminantium (0.7%), Wolbachia sp., Candidatus Ehrlichia rustica (13.5%), Candidatus Ehrlichia urmitei (7%), and an uncultured Ehrlichia sp. (4.2%). Borrelia theileri was identified in one Rhipicephalus microplus tick. Unfortunately, Piroplasmida could not be identified to the species level. This study demonstrates that in Cameroon, ticks harbour a wide variety of microorganisms and present a risk of zoonotic diseases.
Necrotic Enteritis in Broiler Chickens: A Review on the Pathogen, Pathogenesis, and Prevention
Authors: Fathima Shahna , Hakeem Walid Ghazi Al , Shanmugasundaram Revathi , Selvaraj Ramesh K.
Published: October 2022

Clostridium perfringens type A and C are the primary etiological agents associated with necrotic enteritis (NE) in poultry. The predisposing factors implicated in the incidence of NE changes the physical properties of the gut, immunological status of birds, and disrupt the gut microbial homeostasis, causing an over-proliferation of C. perfringens. The principal virulence factors contributing to the pathogenesis of NE are the α-toxin, β-toxin, and NetB toxin. The immune response to NE in poultry is mediated by the Th1 pathway or cytotoxic T-lymphocytes. C. perfringens type A and C are also pathogenic in humans, and hence are of public health significance. C. perfringens intoxications are the third most common bacterial foodborne disease after Salmonella and Campylobacter. The restrictions on the use of antibiotics led to an increased incidence of NE in poultry. Hence, it is essential to develop alternative strategies to keep the prevalence of NE under check. The control strategies rely principally on the positive modulation of host immune response, nutritional manipulation, and pathogen reduction. Current knowledge on the etiology, pathogenesis, predisposing factors, immune response, effect on the gut microbial homeostasis, and preventative strategies of NE in this post-antibiotic era is addressed in this review.
Discovery, Biosynthesis and Biological Activity of a Succinylated Myxochelin from the Myxobacterial Strain MSr12020
Authors: Okoth Dorothy A. , Hug Joachim J. , Garcia Ronald , Müller Rolf
Published: October 2022

Myxobacteria feature unique biological characteristics, including their capability to glide on the surface, undergo different multicellular developmental stages and produce structurally unique natural products such as the catecholate-type siderophores myxochelins A and B. Herein, we report the isolation, structure elucidation and a proposed biosynthesis of the new congener myxochelin B-succinate from the terrestrial myxobacterial strain MSr12020, featuring a succinyl decoration at its primary amine group. Myxochelin-B-succinate exhibited antibacterial growth inhibition and moderate cytotoxic activity against selected human cancer cell lines. This unique chemical modification of myxochelin B might provide interesting insights for future microbiological studies to understand the biological function and biosynthesis of secondary metabolite succinylation.
A Comparative Study of the Dynamics and Diversity of Bdellovibrio and Like Organisms in Lakes Annecy and Geneva
Authors: Ezzedine Jade A. , Scheifler Mathilde , Desdevises Yves , Jacquet Stéphan
Published: October 2022

Bdellovibrio and like organisms (BALOs) are obligate bacterial predators of other Gram-negative bacteria. Here, we used quantitative PCR (qPCR) and recently developed specific primers which target the 16S rRNA gene to explore the abundance and distribution of three families of BALO belonging to the Oligoflexia class (i.e., Bdellovibrionaceae, Peredibacteraceae and Bacteriovoracaceae) over one year in the epilimnion and hypolimnion of Lakes Annecy and Geneva. Peredibacteraceae was the dominant group at all sampling points except at the bottom of Lake Geneva, where Bdellovibrionaceae was found in higher number. In addition, the abundance of BALOs increased significantly during the warmer months. Using high-throughput sequencing (Illumina Miseq), hundreds of OTUs were identified for Bdellovibrionaceae and Peredibacteraceae. Phylogenetic analysis suggests that Bdellovibrionaceae are more diverse than Peredibacteraceae and that some OTUs belong to new species of Bdellovibrionaceae. We also found that dominant OTUs were present simultaneously in the two lakes, while some others were specific to each lake, suggesting an adaptive pattern. Finally, both abundance and diversity of BALOs were poorly associated with abiotic factors except temperature, suggesting the importance of studying biotic relationships, assumed to play a greater role than physico-chemical variables in BALOs’ dynamics and distribution.
Beyond Basic Diversity Estimates—Analytical Tools for Mechanistic Interpretations of Amplicon Sequencing Data
Authors: Trego Anna , Keating Ciara , Nzeteu Corine , Graham Alison , O’Flaherty Vincent , Ijaz Umer Zeeshan
Published: October 2022

Understanding microbial ecology through amplifying short read regions, typically 16S rRNA for prokaryotic species or 18S rRNA for eukaryotic species, remains a popular, economical choice. These methods provide relative abundances of key microbial taxa, which, depending on the experimental design, can be used to infer mechanistic ecological underpinnings. In this review, we discuss recent advancements in in situ analytical tools that have the power to elucidate ecological phenomena, unveil the metabolic potential of microbial communities, identify complex multidimensional interactions between species, and compare stability and complexity under different conditions. Additionally, we highlight methods that incorporate various modalities and additional information, which in combination with abundance data, can help us understand how microbial communities respond to change in a typical ecosystem. Whilst the field of microbial informatics continues to progress substantially, our emphasis is on popular methods that are applicable to a broad range of study designs. The application of these methods can increase our mechanistic understanding of the ongoing dynamics of complex microbial communities.
Mycoplasma hominis Causes DNA Damage and Cell Death in Primary Human Keratinocytes
Authors: Amorim Aline Teixeira , Lino Vanesca de Souza , Marques Lucas Miranda , Martins Davi Jardim , Braga Junior Antonio Carlos Ricardo , Campos Guilherme Barreto , Oliveira Caline Novais Teixeira , Boccardo Enrique , Timenetsky Jorge
Published: October 2022

Mycoplasma hominis can be isolated from the human urogenital tract. However, its interaction with the host remains poorly understood. In this study, we aimed to assess the effects of M. hominis infection on primary human keratinocytes (PHKs). Cells were quantified at different phases of the cell cycle. Proteins involved in cell cycle regulation and apoptosis progression were evaluated. The expression of genes encoding proteins that are associated with the DNA damage response and Toll-like receptor pathways was evaluated, and the cytokines involved in inflammatory responses were quantified. A greater number of keratinocytes were observed in the Sub-G0/G1 phase after infection with M. hominis. In the viable keratinocytes, infection resulted in G2/M-phase arrest; GADD45A expression was increased, as was the expression of proteins such as p53, p27, and p21 and others involved in apoptosis regulation and oxidative stress. In infected PHKs, the expression of genes associated with the Toll-like receptor pathways showed a change, and the production of IFN-γ, interleukin (IL) 1β, IL-18, IL-6, and tumour necrosis factor alpha increased. The infection of PHKs by M. hominis causes cellular damage that can affect the cell cycle by activating the response pathways to cellular damage, oxidative stress, and Toll-like receptors. Overall, this response culminated in the reduction of cell proliferation/viability in vitro.
Interactions between Medications and the Gut Microbiome in Inflammatory Bowel Disease
Authors: Eckenberger Julia , Butler James C. , Bernstein Charles N. , Shanahan Fergus , Claesson Marcus J.
Published: October 2022

In view of the increasing evidence that commonly prescribed, non-antibiotic drugs interact with the gut microbiome, we re-examined the microbiota variance in inflammatory bowel disease (IBD) to determine the degree to which medication and supplement intake might account for compositional differences between disease subtypes and geographic location. We assessed the confounding effects of various treatments on the faecal microbiota composition (16S rRNA gene sequencing) in persons with Crohn’s disease (CD; n = 188) or ulcerative colitis (UC; n = 161) from either Cork (Ireland) or Manitoba (Canada) sampled at three time points. The medication profiles between persons with UC and CD and from different countries varied in number and type of drugs taken. Among Canadian participants with CD, surgical resection and overall medication and supplement usage is significantly more common than for their Irish counterparts. Treatments explained more microbiota variance (3.5%) than all other factors combined (2.4%) and 40 of the 78 tested medications and supplements showed significant associations with at least one taxon in the gut microbiota. However, while treatments accounted for a relatively small proportion of the geographic contribution to microbiome variance between Irish and Canadian participants, additive effects from multiple medications contributed significantly to microbiome differences between UC and CD.
Haemophilus influenzae Carriage among Healthy Children in Portugal, 2015–2019
Authors: Bajanca-Lavado Maria Paula , Cavaco Luís , Fernandes Mariana , Touret Tiago , Candeias Catarina , Simões Alexandra S. , Sá-Leão Raquel
Published: October 2022

Haemophilus influenzae is an important cause of mucosal and invasive infections and a common colonizer of the upper respiratory tract. As there are no recent data on H. influenzae carriage in Portugal, we aimed to characterize carriage samples and investigate possible parallelisms with disease isolates. Between 2016–2019, 1524 nasopharyngeal samples were obtained from children (0–6 years) attending day-care. H. influenzae were serotyped and screened for β-lactamase production. Strains producing β-lactamase and/or those that were encapsulated were further characterized by antibiotype; encapsulated strains were also investigated for MLST and the presence of antimicrobial resistance and virulence genes (extracted from whole genome sequencing). The overall carriage rate was 84.1%. Most isolates (96.7%) were nonencapsulated. Encapsulated strains were of serotypes f (1.8%), e (1.1%), a (0.3%), and b (0.1%). MLST showed clonality within serotypes. Although the lineages were the same as those that were described among disease isolates, colonization isolates had fewer virulence determinants. Overall, 7.5% of the isolates were β-lactamase positive; one isolate had blaTEM-82, which has not been previously described in H. influenzae. A single isolate, which was identified as H. parainfluenzae, had an incomplete f-like cap locus. In conclusion, circulation of serotype b is residual. The few encapsulated strains are genetically related to disease-causing isolates. Thus, surveillance of H. influenzae carriage should be maintained.
Marine Bioprospecting, Biocatalysis and Process Development
Authors: Rodrigues Carlos J. C. , de Carvalho Carla C. C. R.
Published: October 2022

Oceans possess tremendous diversity in microbial life. The enzymatic machinery that marine bacteria present is the result of extensive evolution to assist cell survival under the harsh and continuously changing conditions found in the marine environment. Several bacterial cells and enzymes are already used at an industrial scale, but novel biocatalysts are still needed for sustainable industrial applications, with benefits for both public health and the environment. Metagenomic techniques have enabled the discovery of novel biocatalysts, biosynthetic pathways, and microbial identification without their cultivation. However, a key stage for application of novel biocatalysts is the need for rapid evaluation of the feasibility of the bioprocess. Cultivation of not-yet-cultured bacteria is challenging and requires new methodologies to enable growth of the bacteria present in collected environmental samples, but, once a bacterium is isolated, its enzyme activities are easily measured. High-throughput screening techniques have also been used successfully, and innovative in vitro screening platforms to rapidly identify relevant enzymatic activities continue to improve. Small-scale approaches and process integration could improve the study and development of new bioprocesses to produce commercially interesting products. In this work, the latest studies related to (i) the growth of marine bacteria under laboratorial conditions, (ii) screening techniques for bioprospecting, and (iii) bioprocess development using microreactors and miniaturized systems are reviewed and discussed.
Targeting the Bet-Hedging Strategy with an Inhibitor of Bacterial Efflux Capacity Enhances Antibiotic Efficiency and Ameliorates Bacterial Persistence In Vitro
Authors: Morales Demosthenes , Micheva-Viteva Sofiya , Adikari Samantha , Werner James , Wolinsky Murray , Hong-Geller Elizabeth , Kim Jinwoo , Ojima Iwao
Published: October 2022

Persistence is a bet-hedging strategy in bacterial populations that increases antibiotic tolerance and leads to the establishment of latent infections. In this study, we demonstrated that a synthetic non-toxic taxane-based reversal agent (tRA), developed as an inhibitor of ABC transporter systems in mammalian cancer cells, enhanced antibiotic killing of persister populations from different pathogens, including Burkholderia, Pseudomonas, Francisella, and Yersinia. Acting as an inhibitor of bacterial efflux at 100 nM, tRA99020 enhanced antibiotic efficiency and suppressed the production of natural products of Burkholderia species polyketide synthase (PKS) function. We demonstrate that the metabolites produced by PKS in response to stress by different antibiotics act as inhibitors of mammalian histone deacetylase activity and stimulate cell death. Applying a single-molecule fluorescence in situ hybridization (smFISH) assay, we analyzed on a single-cell level the activation profiles of the persistence regulating pks gene in Burkholderia thailandensis treated with tRA99020 and antibiotics. We posit that a multi-pronged approach encompassing antibiotic therapies and inhibition of efflux systems and fatty acid catabolism will be required for efficient eradication of persistent bacterial populations.
Ecological Importance of Viral Lysis as a Loss Factor of Phytoplankton in the Amundsen Sea
Authors: Eich Charlotte , Biggs Tristan E. G. , van de Poll Willem H. , van Manen Mathijs , Tian Hung-An , Jung Jinyoung , Lee Youngju , Middag Rob , Brussaard Corina P. D.
Published: October 2022

Whether phytoplankton mortality is caused by grazing or viral lysis has important implications for phytoplankton dynamics and biogeochemical cycling. The ecological relevance of viral lysis for Antarctic phytoplankton is still under-studied. The Amundsen Sea is highly productive in spring and summer, especially in the Amundsen Sea Polynya (ASP), and very sensitive to global warming-induced ice-melt. This study reports on the importance of the viral lysis, compared to grazing, of pico- and nanophytoplankton, using the modified dilution method (based on apparent growth rates) in combination with flow cytometry and size fractionation. Considerable viral lysis was shown for all phytoplankton populations, independent of sampling location and cell size. In contrast, the average grazing rate was 116% higher for the larger nanophytoplankton, and grazing was also higher in the ASP (0.45 d−1 vs. 0.30 d−1 outside). Despite average specific viral lysis rates being lower than grazing rates (0.17 d−1 vs. 0.29 d−1), the average amount of phytoplankton carbon lost was similar (0.6 µg C L−1 d−1 each). The viral lysis of the larger-sized phytoplankton populations (including diatoms) and the high lysis rates of the abundant P. antarctica contributed substantially to the carbon lost. Our results demonstrate that viral lysis is a principal loss factor to consider for Southern Ocean phytoplankton communities and ecosystem production.
Longitudinal Study on Extended-Spectrum Beta-Lactamase-E. coli in Sentinel Mallard Ducks in an Important Baltic Stop-Over Site for Migratory Ducks in Germany
Authors: Dreyer Sylvia , Globig Anja , Bachmann Lisa , Schütz Anne K. , Schaufler Katharina , Homeier-Bachmann Timo
Published: October 2022

Antimicrobial resistance (AMR) is a serious global health threat with extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales as the most critical ones. Studies on AMR in wild birds imply a possible dissemination function and indicate their potential role as sentinel animals. This study aimed to gain a deeper insight into the AMR burden of wild waterfowl by sampling semi-wild mallard ducks used as sentinels and to identify if AMR bacteria could be recommended to be added to the pathogens of public health risks to be screened for. In total, 376 cloacal and pooled fecal samples were collected from the sentinel plant over a period of two years. Samples were screened for ESBL-carrying E. coli and isolates found further analyzed using antimicrobial susceptibility testing and whole-genome sequencing. Over the sampling period, 4.26% (16/376) of the samples were positive for ESBL-producing E. coli. BlaCTX-M-1 and blaCTX-M-32 were the most abundant CTX-M types. Although none of the top global sequence types (ST) could be detected, poultry-derived ST115 and non-poultry-related STs were found and could be followed over time. The current study revealed low cases of ESBL-producing E. coli in semi-wild mallard ducks, which proves the suitability of sentinel surveillance for AMR detection in water-associated wildlife.
Spatio-Temporal Distribution of Brucellosis in European Terrestrial and Marine Wildlife Species and Its Regional Implications
Authors: Jamil Tariq , Akar Kadir , Erdenlig Sevil , Murugaiyan Jayaseelan , Sandalakis Vassilios , Boukouvala Evridiki , Psaroulaki Anna , Melzer Falk , Neubauer Heinrich , Wareth Gamal
Published: October 2022

Brucellosis is an important bacterial zoonosis of domestic and wildlife species. This disease has a significant public health concern and is characterized by reproductive failure resulting in economic losses in the livestock industry. Among thirteen known species, B. abortus, B. melitensis, B. suis, and B. canis are human pathogens. Brucellosis has been extensively investigated in humans and domestic animals. However, the situation in wildlife is still not completely reported and studied. Therefore, a systematic literature search and screening were done to clarify the situation of brucellosis in wildlife in Europe. Sixty-five articles from a total of 13,424 reports published between 1991 and 2021 were selected, applying defined inclusion criteria. Wild boars and brown hares were the most often studied terrestrial wildlife species, whereas seals and porpoises were the most often investigated marine wildlife. Poland, Croatia, and Belgium showed the highest seroprevalences of wild boars caused by B. suis biovar 2. In marine wildlife, brucellosis was mainly caused by B. ceti and B. pinnipedialis. Most samples were from carcasses. Thus, sera could not be collected. It is worrisome that B.abortus and B. melitensis were reported from both terrestrial and marine wild animals, posing a zoonotic threat to people exposed to wild animals. Currently, there is no approved vaccine available for wild animals. The main challenges are the development of specific diagnostics and their validation for use in wildlife.
Performance of MALDI-TOF Mass Spectrometry (VITEK MS) in the Identification of Salmonella Species
Authors: Kim Gyu Ri , Kim Si Hyun , Kim Eun-Young , Park Eun Hee , Hwang In Yeong , Jeong Seok Hoon , Kim Hyun Soo , Kim Young Ah , Uh Young , Shin Kyeong Seob , Kim Young Ree , Ryoo Namhee , Shin Jong Hee , Shin Jeong Hwan
Published: October 2022

Salmonella is a major pathogen causing foodborne infections in humans. Salmonella isolates are identified using biochemical and serological tests, including automated systems such as the VITEK2 system. However, there are few reports on Salmonella identification using VITEK MS. Therefore, we aimed to evaluate the usefulness of MALDI-TOF VITEK MS for Salmonella identification. A total of 1389 Salmonella isolates were identified using VITEK MS ver3.0 or ver3.2. All Salmonella isolates were confirmed by serotyping using the Kauffmann-White scheme, and the results were compared with the VITEK MS results. A total of 1389 Salmonella isolates, including 66 serotypes, were correctly identified at the genus level by VITEK MS. However, these systems failed to correctly identify typhoidal Salmonella. Among the five Salmonella enterica ssp. diarizonae isolates, only one was correctly identified, whereas one and three isolates were partially identified and misidentified, respectively. On the other hand, the VITEK2 system successfully identified all typhoidal Salmonella (Typhi and Paratyphi A) and Salmonella enterica ssp. diarizonae isolates. VITEK MS was useful for identifying Salmonella species isolated from clinical specimens; however, additional biochemical tests, such as the VITEK2 System, should be considered to accurately identify Salmonella ser. Typhi, and Salmonella ser. Paratyphi A.
Detection of β-Lactamase Resistance and Biofilm Genes in Pseudomonas Species Isolated from Chickens
Authors: Mohamed Hams M. A. , Alnasser Sulaiman Mohammed , Abd-Elhafeez Hanan H. , Alotaibi Meshal , Batiha Gaber El-Saber , Younis Waleed
Published: October 2022

Bacteria of the genus Pseudomonas are pathogens in both humans and animals. The most prevalent nosocomial pathogen is P. aeruginosa, particularly strains with elevated antibiotic resistance. In this study, a total of eighteen previously identified Pseudomonas species strains, were isolated from chicken. These strains were screened for biofilm formation and antibiotic resistance. In addition, we evaluated clove oil’s effectiveness against Pseudomonas isolates as an antibiofilm agent. The results showed that Pseudomonas species isolates were resistant to most antibiotics tested, particularly those from the β-lactamase family. A significant correlation (p < 0.05) between the development of multidrug-resistant isolates and biofilms is too informal. After amplifying the AmpC-plasmid-mediated genes (blaCMY, blaMIR, DHA, and FOX) and biofilm-related genes (psld, rhlA, and pelA) in most of our isolates, PCR confirmed this relationship. Clove oil has a potent antibiofilm effect against Pseudomonas isolates, and may provide a treatment for bacteria that form biofilms and are resistant to antimicrobials.
Silencing of Salmonella typhimurium Pathogenesis: Atenolol Acquires Efficient Anti-Virulence Activities
Authors: Thabit Abrar K. , Eljaaly Khalid , Zawawi Ayat , Ibrahim Tarek S. , Eissa Ahmed G. , Elbaramawi Samar S. , Hegazy Wael A. H. , Elfaky Mahmoud A.
Published: October 2022

The targeting of bacterial virulence is proposed as a promising approach to overcoming the bacterial resistance development to antibiotics. Salmonella enterica is one of the most important gut pathogens that cause a wide diversity of local and systemic illnesses. The Salmonella virulence is controlled by interplayed systems namely Quorum sensing (QS) and type three secretion system (T3SS). Furthermore, the Salmonella spy on the host cell via sensing the adrenergic hormones enhancing its virulence. The current study explores the possible anti-virulence activities of β-adrenoreceptor blocker atenolol against S. enterica serovar Typhimurium in vitro, in silico, and in vivo. The present findings revealed a significant atenolol ability to diminish the S. typhimurium biofilm formation, invasion into HeLa cells, and intracellular replication inside macrophages. Atenolol significantly downregulated the encoding genes of the T3SS-type II, QS receptor Lux analogs sdiA, and norepinephrine membranal sensors qseC and qseE. Moreover, atenolol significantly protected mice against S. typhimurium. For testing the possible mechanisms for atenolol anti-virulence activities, an in silico molecular docking study was conducted to assess the atenolol binding ability to QS receptor SdiA and norepinephrine membranal sensors QseC. Atenolol showed the ability to compete on the S. typhimurium targets. In conclusion, atenolol is a promising anti-virulence candidate to alleviate the S. typhimurium pathogenesis by targeting its QS and T3SS systems besides diminishing the eavesdropping on the host cells.
Prevalence of Bacterial Pathogens among Symptomatic–SARS-CoV-2 PCR-Negative Patients
Authors: Ahmed Naveed , Habib Saman , Muzzammil Moazza , Rabaan Ali A. , Turkistani Safaa A. , Garout Mohammed , Halwani Muhammad A. , Aljeldah Mohammed , Al Shammari Basim R. , Sabour Amal A. , Alshiekheid Maha A. , Abdalla Areeg N. K. , Alestad Jeehan H. , Alhumaid Saad , Lopes Bruno Silvester , Yean Chan Yean
Published: October 2022

The epidemiological and clinical aspects of coronavirus disease-2019 (COVID-19) have been subjected to several investigations, but little is known about symptomatic patients with negative SARS-CoV-2 PCR results. The current study investigated patients who presented to the hospital with respiratory symptoms (but negative SARS-CoV-2 RT-PCR results) to determine the prevalence of bacterial pathogens among these patients. A total of 1246 different samples were collected and 453 species of bacterial pathogens were identified by culture. Antibiotic susceptibility testing was performed via the Kirby Bauer disc diffusion test. Patients showed symptoms, such as fever (100%), cough (83%), tiredness (77%), loss of taste and smell (23%), rigors (93%), sweating (62%), and nausea (81%), but all tested negative for COVID-19 by PCR tests. Further examinations revealed additional and severe symptoms, such as sore throats (27%), body aches and pain (83%), diarrhea (11%), skin rashes (5%), eye irritation (21%), vomiting (42%), difficulty breathing (32%), and chest pain (67%). The sum of n = 1246 included the following: males, 289 were between 5 and 14 years, 183 (15–24 years), 157 (25–34 years), 113 (35–49 years), and 43 were 50+ years. Females: 138 were between 5 and 14 years, 93 (15–24 years), 72 (25–34 years), 89 (35–49 years), and 68 were 50+ years. The Gram-positive organisms isolated were Staphylococcus aureus (n = 111, 80.43%, MRSA 16.6%), E. faecalis (n = 20, 14.49%, VRE: 9.4%), and Streptococcus agalactiae (n = 7, 5.07%), while, Gram-negative organisms, such as E. coli (n = 135, 42.85%, CRE: 3.49%), K. pneumoniae (n = 93, 29.52%, CRE: 1.58%), P. aeruginosa (n = 43, 13.65%), C. freundii (n = 21, 6.66%), Serratia spp. (n = 8, 2.53%), and Proteus spp. (n = 15, 4.76%) were identified.
Polycyclic Aromatic Hydrocarbon-Degrading Bacteria in Three Different Functional Zones of the Cities of Moscow and Murmansk
Authors: Sazonova Olesya I. , Gavrichkova Olga , Ivanova Anastasia A. , Petrikov Kirill V. , Streletskii Rostislav A. , Sarzhanov Dmitriy A. , Korneykova Maria V. , Novikov Andrey I. , Vasenev Viacheslav I. , Ivashchenko Kristina V. , Slukovskaya Marina V. , Vetrova Anna A.
Published: October 2022

We performed a comparative study of the total bacterial communities and communities of cultivable polycyclic aromatic hydrocarbons (PAH)-degrading bacteria in different functional zones of Moscow and Murmansk that were formed under the influence of the PAH composition in road and leaf dust. The PAHs were determined by high-performance liquid chromatography (HPLC); the bacterial communities’ diversity was assessed by metabarcoding. The degraders were isolated by their direct plating on a medium with the PAHs. The PAH total quantity declined in the leaf dust from the traffic to the recreational zone. For the road dust, a negative gradient with pollution was observed for Rhodococcus and Acinetobacter degraders and for their relative abundance in the microbiome for the functional zones of Moscow. The opposite effect was observed in the Murmansk leaf dust for the Rothia and Pseudomonas degraders and in the Moscow road dust for Microbacterium. The PCA and linear regression analyses showed that the Micrococcus degraders in the dust were sensitive to anthropogenic pollution, so they can be used as a tool for monitoring anthropogenic changes in the biosphere. The data on the degraders’ and microbial communities’ diversity suggest that minor degrading strains can play a key role in PAH degradation.
Microbial Effectors: Key Determinants in Plant Health and Disease
Authors: Todd Jewel Nicole Anna , Carreón-Anguiano Karla Gisel , Islas-Flores Ignacio , Canto-Canché Blondy
Published: October 2022

Effectors are small, secreted molecules that alter host cell structure and function, thereby facilitating infection or triggering a defense response. Effectoromics studies have focused on effectors in plant–pathogen interactions, where their contributions to virulence are determined in the plant host, i.e., whether the effector induces resistance or susceptibility to plant disease. Effector molecules from plant pathogenic microorganisms such as fungi, oomycetes and bacteria are major disease determinants. Interestingly, the effectors of non-pathogenic plant organisms such as endophytes display similar functions but have different outcomes for plant health. Endophyte effectors commonly aid in the establishment of mutualistic interactions with the plant and contribute to plant health through the induction of systemic resistance against pathogens, while pathogenic effectors mainly debilitate the plant’s immune response, resulting in the establishment of disease. Effectors of plant pathogens as well as plant endophytes are tools to be considered in effectoromics for the development of novel strategies for disease management. This review aims to present effectors in their roles as promotors of health or disease for the plant host.
Emerging Evidence on Tenebrio molitor Immunity: A Focus on Gene Expression Involved in Microbial Infection for Host-Pathogen Interaction Studies
Authors: Petronio Petronio Giulio , Pietrangelo Laura , Cutuli Marco Alfio , Magnifico Irene , Venditti Noemi , Guarnieri Antonio , Abate Getnet Atinafu , Yewhalaw Delenasaw , Davinelli Sergio , Di Marco Roberto
Published: October 2022

In recent years, the scientific community’s interest in T. molitor as an insect model to investigate immunity and host-pathogen interactions has considerably increased. The reasons for this growing interest could be explained by the peculiar features of this beetle, which offers various advantages compared to other invertebrates models commonly used in laboratory studies. Thus, this review aimed at providing a broad view of the T. molitor immune system in light of the new scientific evidence on the developmental/tissue-specific gene expression studies related to microbial infection. In addition to the well-known cellular component and humoral response process, several studies investigating the factors associated with T. molitor immune response or deepening of those already known have been reported. However, various aspects remain still less understood, namely the possible crosstalk between the immune deficiency protein and Toll pathways and the role exerted by T. molitor apolipoprotein III in the expression of the antimicrobial peptides. Therefore, further research is required for T. molitor to be recommended as an alternative insect model for pathogen-host interaction and immunity studies.