Bacterial pathogens

Wed, 02/26/2020 - 03:36
ABSTRACT The temporal switching of serotypes from serotype Ogawa to Inaba and back to Ogawa was identified in Vibrio cholerae O1, which was responsible for seasonal outbreaks of cholera in Dhaka during the period 2015 to 2018. In order to delineate the factors responsible for this serotype transition, we performed whole-genome sequencing (WGS) of V. cholerae O1 multidrug-resistant strains...
Wed, 02/26/2020 - 03:36
ABSTRACT The Salmonella enterica subsp. enterica serovar Typhimurium PhoPQ two-component system is activated within the intracellular phagosome environment, where it promotes remodeling of the outer membrane and resistance to innate immune antimicrobial peptides. Maintenance of the PhoPQ-regulated outer membrane barrier requires PbgA, an inner membrane protein with a transmembrane domain...
Wed, 02/26/2020 - 03:36
ABSTRACT A major obstacle in infection biology is the limited ability to recapitulate human disease trajectories in traditional cell culture and animal models, which impedes the translation of basic research into clinics. Here, we introduce a three-dimensional (3D) intestinal tissue model to study human enteric infections at a level of detail that is not achieved by conventional two-dimensional...
Wed, 02/26/2020 - 03:36
ABSTRACT Staphylococcus epidermidis is a leading cause of nosocomial infections in patients with a compromised immune system and/or an implanted medical device. Seventy to 90% of S. epidermidis clinical isolates are methicillin resistant and carry the mecA gene, present in a mobile genetic element (MGE) called the staphylococcal cassette chromosome mec (SCCmec) element. Along with the presence of...
Wed, 02/26/2020 - 03:36
ABSTRACT Many patients with severe infections receive inappropriate empirical treatment, and rapid detection of bacterial antibiotic susceptibility can improve clinical outcome and reduce mortality. To this end, we have developed a multiplex fluidic chip for rapid phenotypic antibiotic susceptibility testing of bacteria. A total of 21 clinical isolates of Escherichia coli, Klebsiella pneumoniae,...
Wed, 02/26/2020 - 03:34
Author(s): Yibei Zhang, Huanhuan Liu, Dan Gu, Xingxu Lu, Xiaohui Zhou, Xiaodong XiaVibrio parahaemolyticus is a common foodborne pathogen in seafood and represents a major threat to human health worldwide. In this study, we identified that PhoR, a histidine kinase, is involved in the regulation of swarming and flagella assembly. RNA sequencing analysis showed that 1122 genes were differentially...
Wed, 02/26/2020 - 03:33
Author(s): Ningning Zhao, Junfeng Lv, Yaru Lu, Yingying Jiang, Hongmei Li, Yumin Liu, Xiao Zhang, Xiaomin ZhaoThe microneme adhesive repeats (MAR) of Eimeria tenella microneme protein 3 (EtMIC3) are associated with binding to and invasion of host cells. Adhesion and invasion-related proteins or domains are often strongly immunogenic, immune responses mounted against these factors that play a key...
Wed, 02/26/2020 - 03:29
Mycobacteria use type VII secretion systems (T7SSs) to translocate proteins across their diderm cell envelope. We previously showed that the Mycobacterium tuberculosis ESX‐5 T7SS is unable to complement secretion in a Mycobacterium marinum esx‐5 mutant, suggesting species‐specificity in secretion. In this study, we established that a specific domain, i.e. linker 2, of the membrane ATPase EccC5 is...
Wed, 02/26/2020 - 03:29
In Vibrio parahaemolyticus, the iron uptake regulator Fur represses genes involved in iron acquisition and swarming. The Fur regulon also includes a previously uncharacterized regulator fcrX. Overproduction of FcrX, which is a small tetratricopeptide repeat‐containing protein, affects phenotypes in multiple bacterial species. FcrX interacts with V. parahaemolyticus and Escherichia coli Fur....
Wed, 02/26/2020 - 03:27
Salmonella is an important pathogen and is a world-wide threat to food safety and public health. Surveillance of serotypes and fundamental biological and biochemical studies are supported by a wide variety of established and emerging bioanalytical techniques. These include classic serotyping based on the Kauffmann–White nomenclature and the emerging whole genome sequencing strategy. Another...
Wed, 02/26/2020 - 03:27
In this study we compared nine Shiga toxin (Stx)-producing Escherichia coli O157:H7 patient isolates for Stx levels, stx-phage insertion site(s), and pathogenicity in a streptomycin (Str)-treated mouse model. The strains encoded stx2a, stx1a and stx2a, or stx2a and stx2c. All of the strains elaborated 105-106 cytotoxic doses 50% (CD50) into the supernatant after growth in vitro as measured on...
Tue, 02/25/2020 - 03:42
by Michele Lunelli, Antje Kamprad, Jörg Bürger, Thorsten Mielke, Christian M. T. Spahn, Michael Kolbe The Type III Secretion Systems (T3SS) needle complex is a conserved syringe-shaped protein translocation nanomachine with a mass of about 3.5 MDa essential for the survival and virulence of many Gram-negative bacterial pathogens. This system is composed of a membrane-embedded basal body and an...
Tue, 02/25/2020 - 03:41
Escherichia coli serogroups O157, O26, O45, O103, O111, O121, and O145, when carrying major virulence genes, the Shiga toxin genes stx1 and stx2 and the intimin gene eae, are important foodborne pathogens. They are referred to as the "top 7" Shiga toxin-producing E. coli (STEC) serogroups and were declared by the USDA as adulterants to human health. Since top 7 serogroup-positive cattle feces and...
Tue, 02/25/2020 - 03:41
In Listeria monocytogenes the full details of how stress signals are integrated into the B regulatory pathway are not yet available. To help shed light on this question we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (B). These mutants were tested for acid tolerance, a trait that is known to be under B...
Tue, 02/25/2020 - 03:37
Author(s): Seok Hyeon Na, Dong Chan Moon, Hee Young Kang, Hyun-Ju Song, Su-Jeong Kim, Ji-Hyun Choi, Jang Won Yoon, Soon-Seek Yoon, Suk-Kyung LimAbstractGlobal dissemination of non-typhoidal Salmonella producing extended-spectrum β-lactamase (ESBL) is a public-health concern. Recently, the prevalence of Salmonella spp. resistant to third-generation cephalosporins has been increasing in food-...
Tue, 02/25/2020 - 03:30
The genus Brucella comprises major pathogenic species causing disease in livestock and humans, e.g. B. melitensis. In the past few years, the genus has been significantly expanded by the discovery of phylogenetically more distant lineages comprising strains from diverse wildlife animal species, including amphibians and fish. The strains represent several potential new species, with B. inopinata...
Tue, 02/25/2020 - 03:30
Tuberculosis remains one of the leading causes of death from a single pathogen globally. It is estimated that 1/4 of the world’s population harbors latent tuberculosis, but only a 5–10% of patients will develop active disease. During latent infection, Mycobacterium tuberculosis can persist unaffected by drugs for years in a non-replicating state with low metabolic activity. The rate of the...
Tue, 02/25/2020 - 03:30
It is well-established that the spread of many multidrug-resistant (MDR) bacteria is predominantly clonal. Interestingly the international clones/sequence types (STs) of most pathogens emerged and disseminated during the last three decades. Strong experimental evidence from multiple laboratories indicate that diverse fitness cost associated with high-level resistance to fluoroquinolones...
Tue, 02/25/2020 - 03:30
This study measured total serum immunoglobulin A (IgA), immunoglobulin G (IgG)1, IgG2a response against whole cell antigen (WCA), outer membrane protein (OMP), periplasmic protein (PP), cytoplasmic protein (CP), and crude Brucella protein (CBP) of Brucella abortus in experimental brucellosis induced with B. abortus biotype 1 in Sprague Dawley (SD) rats during a 17-week infection period. Six- to 8...
Mon, 02/24/2020 - 04:11
Author(s): Bowen Chen, Jiaming Huang, Huihui Li, Qiao-Hui Zeng, Jing Jing Wang, Haiquan Liu, Yingjie Pan, Yong ZhaoAbstractVibrio parahaemolyticus is the leading pathogen in seafoods. This study established the efficient blue light-emitting diode (LED) photodynamic inactivation (PDI) to eradicate Vibrio parahaemolyticus and its biofilm with photosensitizer curcumin, and the antibacterial and...
Mon, 02/24/2020 - 03:59
Copper is an essential element but in excess is highly toxic and therefore cytoplasmic levels must be tightly controlled. Member of the genus Burkholderia are highly resistant to various heavy metals and are often isolated from acidic soils where copper bioavailability is high. In this study, we employed transposon sequencing (Tn‐Seq) to identify copper resistance genes in Burkholderia...
Mon, 02/24/2020 - 03:59
Efficacy of pulsed ultraviolet (PUV) to inactivate Salmonella pure culture and on inoculated black peppercorns was evaluated. Black peppercorns inoculated with Salmonella were subjected to PUV treatment (0.28 J/cm2/pulse) using two different sample holders, on a traditional flat surface or on a wave‐shaped surface to increase surface exposure of peppercorns to PUV through light reflection. The...
Mon, 02/24/2020 - 03:57
A model for growth of Salmonella Newport on Romaine lettuce as a function of time and temperature was developed and validated in Excel using Neural Tools and @Risk. The model simulates growth of a chicken isolate of Salmonella Newport on Romaine lettuce following cross‐contamination from raw chicken during meal preparation. The model fills an important data gap in risk assessments for Salmonella...
Sun, 02/23/2020 - 03:37
Author(s): Retno Murwani, Andri Cahyo Kumoro, Ambariyanto Ambariyanto, Elena N. NaumovaAbstractFish roes are consumed globally as a delicacy and an important seafood-based source of macro and micro-nutrients that is intensively produced in Indonesia. The connective material holding the roes i.e. the skeins are also high in protein and therefore could be utilized as nutritious protein supplement...
Sun, 02/23/2020 - 03:35
Author(s): M. Hilliar, C. Keerqin, C.K. Girish, R. Barekatain, S.-B. Wu, R.A. SwickAbstractNecrotic enteritis (NE) is an infection of the gastrointestinal tract and is estimated to cost the global poultry industry billions of dollars annually. A study was conducted to examine whether reducing the crude protein might offset the severity of NE in broilers experimentally challenged with Eimeria spp...
Sun, 02/23/2020 - 03:31
Aims This experimental study focuses on survival and consistence of Vibrio parahaemolyticus in cold water sediments and how increasing temperature and nutritional availability can affect growth. Methods and Results A pathogenic strain of V. parahaemolyticus was inoculated in seawater microcosms containing bottom sediment. Gradually, during 14 days, the temperature was upregulated from 8 to 21°C....
Sat, 02/22/2020 - 03:39
Antibiotic tolerance is an underappreciated antibiotic escape strategy that is associated with recurrent and relapsing infections, as well as acting as a precursor to resistance. Tolerance describes the ability of a bacterial population to survive transient exposure to an otherwise lethal concentration of antibiotic without exhibiting an elevated MIC. It is detected in time-kill assays as a lower...
Sat, 02/22/2020 - 03:39
The Mycobacterium tuberculosis β-lactamase BlaC is a broad-spectrum β-lactamase that can convert a range of β-lactam antibiotics. Enzymes with low specificity are expected to exhibit active-site flexibility. To probe the motions in BlaC, we studied the dynamic behavior in solution using nuclear magnetic resonance (NMR) spectroscopy. 15N relaxation experiments show that BlaC is...
Sat, 02/22/2020 - 03:39
Oral fosfomycin trometamol is licensed as a single oral dose for the treatment of uncomplicated urinary tract infections, with activity against multidrug-resistant uropathogens. The impact of interindividual variability in urinary concentrations on antimicrobial efficacy, and any benefit of giving multiple doses, is uncertain. We therefore performed pharmacodynamic profiling of oral fosfomycin,...
Sat, 02/22/2020 - 03:39
The threat of diminished antibiotic discovery has global health care in crisis. In the United States, it is estimated each year that over 2 million bacterial infections are resistant to first-line antibiotic treatments and cost in excess of 20 billion dollars. Many of these cases result from infection with the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae,...
Sat, 02/22/2020 - 03:34
Author(s): Daniele Martinelli, Sebastiano Arceri, Livio Tronconi, Cristina TassorelliAbstractMigraine is a highly prevalent and disabling disorder accounted among the primary headaches. It is the expression of a complex, and not yet fully understood, pathophysiology involving the sensitization of peripheral and central nociceptive pathways. In this review we succinctly illustrate the molecular,...
Sat, 02/22/2020 - 03:30
This study investigated the effect of xylanase supplementation of a plant protein‐enriched diet on the growth performance and intestinal immune function of grass carp grow‐out (Ctenopharyngodon idella). Five hundred forty healthy grass carp grow‐out (232.74 ± 0.12 g) were fed diets containing graded levels of xylanase for 60 days. The fish were then challenged with Aeromonas hydrophila for 14 ...
Sat, 02/22/2020 - 03:28
In Rhizobium-legume symbiosis, the bacteria are converted into nitrogen-fixing bacteroids. In many legume species, differentiation of the endosymbiotic bacteria is irreversible, culminating in definitive loss of their cell division ability. This terminal differentiation is mediated by plant peptides produced in the symbiotic cells. In Medicago truncatula more than ∼700 nodule-specific cysteine-...
Sat, 02/22/2020 - 03:28
Accumulating evidence has indicated that the multiple drug resistant Vibrio parahaemolyticus may pose a serious threat to public health and economic concerns for humans globally. Here, two lytic bacteriophages, namely vB_VpS_BA3 and vB_VpS_CA8, were isolated from sewage collected in Guangzhou, China. Electron microscopy studies revealed both virions taxonomically belonged to the Siphoviridae...
Sat, 02/22/2020 - 03:28
Tubercular Mycobacteria and Legionella pneumophila are the causative agents of potentially fatal respiratory diseases due to their intrinsic pathogenesis but also due to the emergence of antibiotic resistance that limits treatment options. The aim of our study was to explore the antimicrobial activity of a small ligand-based chemical library of 1255 structurally diverse compounds. These compounds...
Sat, 02/22/2020 - 03:28
Listeria monocytogenes (LM) is a gram-positive facultative intracellular pathogen that could stimulate host to produce inflammatory response, cell-mediated immunity, and humoral immunity. In this study, an attenuated live vector vaccine for Aeromonas hydrophila (AH) named EGDeABdd-dat-ompW was successfully constructed using an attenuated vector named EGDeABdd, in which dal, dat, actA, and inlB...
Fri, 02/21/2020 - 04:19
Like many other pathogens, Vibrio cholerae, the causative agent of cholera, can modulate its gene expression to combat stresses encountered in both aquatic and host environments, including stress posed by reactive oxygen species (ROS). We previously reported that the virulence activator AphB in V. cholerae is involved in ROS resistance. In this study, we found that another key virulence regulator...
Fri, 02/21/2020 - 04:19
Multidrug efflux systems belonging to the resistance-nodulation-division (RND) superfamily are ubiquitous in Gram-negative bacteria. RND efflux systems are often associated with multiple antimicrobial resistance and also contribute to the expression of diverse bacterial phenotypes including virulence, as documented in the intestinal pathogen Vibrio cholerae, the causative agent of the severe...
Fri, 02/21/2020 - 04:19
The twin-arginine translocation (Tat) system is involved in not only a wide array of cellular processes but also pathogenesis in many bacterial pathogens; thus, this system is expected to become a novel therapeutic target to treat infections. To the best of our knowledge, involvement of the Tat system has not been reported in the gut infection caused by Citrobacter rodentium. Here, we studied the...
Fri, 02/21/2020 - 04:19
Salmonella enterica serovar Pullorum is the pathogen of pullorum disease, which leads to severe economic losses in many developing countries. In contrast to the strong inflammatory response induced by Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis, S. Pullorum causes systemic infection with little inflammation. The effector proteins secreted by Salmonella...
Fri, 02/21/2020 - 04:19
RNA thermometers are cis-acting riboregulators that mediate the posttranscriptional regulation of gene expression in response to environmental temperature. Such regulation is conferred by temperature-responsive structural changes within the RNA thermometer that directly result in differential ribosomal binding to the regulated transcript. The significance of RNA thermometers in controlling...
Fri, 02/21/2020 - 04:19
Modeling host-pathogen interactions with human intestinal epithelia using enteroid monolayers on permeable supports (such as Transwells) represents an alternative to animal studies or use of colon cancer-derived cell lines. However, the static monolayer model does not expose epithelial cells to mechanical forces normally present in the intestine, including luminal flow and serosal blood flow (...
Fri, 02/21/2020 - 04:19
To understand the role of major histocompatibility complex class I (MHC-I) and MHC-II in vaccine-mediated protection against Coxiella burnetii, we evaluated the protective efficacy of a formalin-inactivated C. burnetii Nine Mile phase I vaccine (PIV) in β2-microglobulin-deficient (B2m KO) and MHC-II-deficient (MHC-II KO) mice. Vaccination reduced disease severity in wild-type (WT) and B2m KO...
Fri, 02/21/2020 - 04:19
Coxiella burnetii is an obligate intracellular bacterial pathogen that replicates inside the lysosome-derived Coxiella-containing vacuole (CCV). To establish this unique niche, C. burnetii requires the Dot/Icm type IV secretion system (T4SS) to translocate a cohort of effector proteins into the host cell, which modulate multiple cellular processes. To characterize the host-pathogen interactions...
Fri, 02/21/2020 - 04:17
Author(s): Zhitao Wang, Yanbing Zhang, Leyi Wang, Jianchao Wei, Ke Liu, Donghua Shao, Beibei Li, Lihong Liu, Frederik Widén, Zhiyong Ma, Yafeng QiuAbstractBackgroundBordetella bronchiseptica (B. bronchiseptica), as an opportunistic pathogen, can cause respiratory diseases in a variety of animals, including humans. In additional to being involved in porcine atrophic rhinitis through coinfection...
Fri, 02/21/2020 - 04:14
Author(s): Inês Azevedo, Joana Barbosa, Helena Albano, Paula TeixeiraAbstractIn response to nutritional and health concerns, the food industry has begun to offer a wider variety of products that reflect changing consumer preferences. In addition to traditional alheiras, made with pork and/or poultry meats, other varieties of alheiras (“innovative”) made from codfish, mushrooms, tofu, soy and...
Fri, 02/21/2020 - 04:14
Author(s): John Burnett, Sophie Tongyu Wu, Henk C. den Bakker, Peter W. Cook, Deklin R. Veenhuizen, Susan R. Hammons, Manpreet Singh, Haley F. OliverAbstractThe purpose of this study was to determine the prevalence of Listeria monocytogenes and Salmonella enterica in retail produce environments and to elucidate possible ecological niches. Thirty environmental samples per store were collected...
Fri, 02/21/2020 - 04:14
Author(s): Martina Darmanin, Dmytro Kozak, Jefferson de Oliveira Mallia, Renald Blundell, Ruben Gatt, Vasilis P. ValdramidisAbstractChemical methods are still considered as mainstay in the agro-food sector to improve the safety of seeds and reduce crop losses. Atmospheric plasma to produce functionalised water is emerging as a sustainable alternative for this. Microbial contamination of food...
Fri, 02/21/2020 - 04:06
LWT
Author(s): Pochanart Kanjan, Phat SakpetchAbstractThe objective of this study was to examine the safety and functional properties of Staphylococcus simulans PMRS35 isolated from Budu. This strain possessed good lipase activity and moderate protease activity, tolerated 25% of salt, and did not exhibit decarboxylase activity. In addition, this strain displayed not only negative results towards...
Fri, 02/21/2020 - 04:00
A key unmet food safety need remains the objective assessment of human milk spoilage. Experiments were conducted using a simplified human milk spoilage model based on goat's milk as a human milk surrogate, spiked with a single bacterial strain (S. epidermidis), in which pH and carbon dioxide (CO2) concentration were measured along with bacteria count over 160 hr. Bacteria count correlated highly...

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