Opportunistic Pathogenic Bacteria Research Articles

PREVENTION OF INTESTINAL INFECTIONS OF BACTERIAL ETIOLOGY IN PIGS

Intestinal infections of bacterial etiology are among the most common diseases in pigs of different age groups. Healthy gastrointestinal tract is the basis for successful pig farming. Therefore, the prevention and control of major gastrointestinal infections is a key to farm profitability. Intestinal infections are caused by both pathogenic and opportunistic pathogenic bacteria. The most common diseases caused by pathogenic microorganisms include dysentery, ileitis and salmonellosis. Their causative agents are the bacteria Brachyspira spp., Lawsonia spp. and Salmonella spp. respectively. The most common opportunistic pathogenic bacteria are: Escherichia coli, Clostridium spp. and Proteus spp. Bacterial intestinal infections are diverse and widespread, and therefore cause significant economic losses for livestock farms. They suffer significant losses due to animal mortality, reduced productivity and, as a result, increased treatment costs. Therefore, the efforts of scientists should be aimed at creating innovative approaches and effective therapeutic agents that would not only treat but also prevent bacterial intestinal infections. The article presents data on traditional and innovative approaches to the prevention of bacterial intestinal infections in pigs. The advantages of using feed additives for the prevention and treatment of bacterial intestinal infections in pigs are described.

Quorum sensing related activities of beneficial and pathogenic bacteria have important implications for plant and human health.

Eukaryotic organisms co-evolved with microbes from the environment forming holobiotic meta-genomic units. Members of host-associated microbiomes have commensalic, benefical / symbiotic or pathogenic phenotypes. More than 100 years ago, Lorenz Hiltner, pioneer of soil microbiology, introduced the term "Rhizosphere" to characterize the observation that a high density of saprophytic, beneficial and pathogenic microbes are attracted by root exudates. The balance between these types of microbes decide about the health of the host. Nowadays we know, that for the interaction of microbes with all eukaryotic hosts similar principles and processes of cooperative and competitive functions are in action. Small diffusible molecules like (phyto)hormones, volatiles and quorum sensing signals are examples for mediators of interspecies and cross-kingdom interactions. Quorum sensing (QS) of bacteria is mediated by different auto-inducible metabolites in a density dependent manner. In this perspective publication, the role of QS-related activities for the health of hosts will be discussed focussing mostly on N-acyl-homoserine lactones (AHL). It is also considered that in some cases very close phylogenetic relations exist between plant beneficial and opportunistic human pathogenic bacteria. Based on a genome and system-targeted new understanding, sociomicrobiological solutions are possible for the biocontrol of diseases and the health improvement of eukaryotic hosts.

Antimicrobial spiroketal macrolides and dichloro-diketopiperazine from Micromonospora sp. FIMYZ51

Four compounds (1–4) featuring with an L-rhodinose and spiroketal, possess uncommon continuous hydroxy groups in the macrolide skeleton, and a dichloro-diketopiperazine (5) were isolated from a marine derived Micromonospora sp. FIMYZ51. The determination of the relative and absolute configurations of all isolates was achieved by extensive spectroscopic analyses, single-crystal X-ray diffraction analysis, and ECD calculations. According to structural characteristic and genomic sequences, a plausible biosynthetic pathway for compound 1-4 was proposed and a spirocyclase was inferred to be responsible for the formation of the rare spirocyclic moiety. Compounds 1-4 exhibited potent antifungal activities which is equal to itraconazole against Aspergillus niger. Compounds 1-5 exhibited different degree of inhibitory activities against opportunistic pathogenic bacteria of endocarditis (Micrococcus luteus) with MIC values ranging from 0.0625 μg/mL to 32 μg/mL. Compounds 2 and 3 showed moderate cytotoxicity against drug-resistant tumor cell lines (Namalwa and U266). The result not only provides active lead-compounds, but also reveal the potential of the spirocyclase gene resources from Micromonospora sp., which highlights the promising potential of the strain for biomedical applications.

Влияние антибактериального рассола на качество и микробиологическую безопасность продуктов из мяса

Nomad livestock farming is an extra raw material resource for regions with harsh climate. Foods based on meat of indigenous animals expand the range of products with high consumer properties. The quality and safety of meat products usually depend on the brine. The present research featured the effect of brine with Island moss (Cetrária islándica (L.) Ach.) on the sensory profile and microbiological safety of meat products.
 The study involved meat of two-year-old indigenous cows, as well as multicomponent antibacterial and standard extrusion brines. The brine was injected with a syringe-injector with a hollow perforated needle at a 20 mm pitch. The tenderization took place in a universal express tenderizer with a rotation speed of 16 rpm and lasted for 10 h. The shelf-life was determined based the on microbiological, chemical, and sensory indicators.
 By the end of the reserve shelf-life, the total microbial count was 1.2×103 CFU/g in the control and 1.0×103 CFU/g in the experimental sample. No opportunistic pathogenic bacteria or microorganisms were detected. No opportunistic pathogenic microorganisms were revealed when the microbiological parameters were studied in standard quantities and in quantities increased by an order of magnitude.
 The changes in acid and peroxide numbers during storage indicated a stable oxidation of the fat component in the experimental sample. Its sensory evaluation exceeded the control sample by 0.9 points in terms color, texture, and smell. The meat marinated with C. islándica compiled with the quality standard and had a shelf-life which exceeded that of the traditionally-marinated meat by 5 days.

Severe Acute Hepatitis of Unknown Etiology in Pediatric Patients: Multidisciplinary Clinical Approach

Introduction: In mid-2022, the World Health Organization (WHO) declared a moderate-risk outbreak due to an increase in severe acute hepatitis cases of unknown etiology in children. Several reports suggested a viral infection link, with the outbreak spanning over 35 countries. By June 2022, Mexico reported 69 probable cases across 5 entities to the WHO. Case Presentation: A 4-year-old boy presented with vomiting, jaundice, choluria, and hepatomegaly. A multidisciplinary approach was employed, using an algorithm developed exclusively for clinical, epidemiological, and biochemical follow-up. Despite the negative identification of any associated microorganism and the absence of antibodies, liver function tests remained elevated. A fine needle liver biopsy was performed for diagnostic support, followed by histopathological study and sequencing and analysis of the complete high-depth transcriptome. Transcriptome analysis identified dysbiosis-related intestinal microbiota, including increased enterogenic and opportunistic pathogenic bacteria of the genus Clostridium, as well as HERV-K113, implicated in autoimmune disease development. Conclusions: The study's findings suggest possible immune-mediated mechanisms involving dysbiosis of the gut microbiota and the potential role of HERV-K113. Management and control of acute liver disease depend on specific causes, with the main challenge being early determination and implementation of optimal management strategies. The exact pathological mechanisms underlying pediatric acute hepatitis of unknown etiology remain elusive, warranting further studies to confirm or refute these hypotheses and elucidate the underlying pathological mechanisms

Study the Phenotypic and Antimicrobial Susceptibility of Pseudomonas aeruginosa Isolated Clinically from Baghdad Hospitals

Pseudomonas aeruginosa, is negative to gram stain, take the rod shape and considered as strictly aerobic. the most affect bacteria in nosocomial infection. P.aeruginosa is an opportunistic pathogen bacterium that can made serious infections in human who are immune compromised, such as urinary tract infection, skin and ear infection, and others. One hundred twenty one sample were taken from patients in different sites of infections (ear, wound, UTI , burn) from AL-Yarmouk, Ghazi Al-Hariri hospitals in Baghdad during the period from November 2016 to February 2017. Fifty seven isolates were diagnoses as P. aeruginosa by characteristic in culture media, tests and API 20E. forty isolates involved in our study ten from each source. Antibiotic susceptibility test performed for forty clinically isolates of P. aeruginosa by the disk diffusion method against some antibiotics belong to different group and the results revealed that bacteria is multi-drug resistance (MRD) as well, revealed the most compound that have activity against Pseudomonas. aeruginosa were Imipenem, Pipracillin, and Ceftazidime. Biofilms are currently estimated and the P. aeruginosa reflect high ability to produce biofilm. All isolates used in this study formed biofilm with differences in thickness of formed layer. In this study, we concluded P. aeruginosa is one of the most common gram-negative bacteria involved in hospital infections causing opportunistic infection because they have intrinsically and acquired resistant to a number of antimicrobial agents and produces a number of exoproducts which are implicated in the pathogenesis of P. aeruginosa infections.

Assessment of airborne bacteria in the indoor of public-use facilities concentrated on influencing factors and opportunistic pathogenic bacteria

AbstractFor public-use facilities in urban centers with high occupancy, it is imperative to effectively manage opportunistic pathogenic bacteria due to the diverse range of users, including the immunocompromised population, such as the elderly, children. Therefore, we investigated the concentration of airborne bacteria at several public-use facilities in urban centers in South Korea. The level of total airborne bacteria in the facilities was positively correlated with user density and CO2 levels. Notably, subway compartments demonstrated particularly high levels of airborne bacteria. Subway compartments and daycare centers contained opportunistic pathogenic bacteria associated with antibiotic resistance. The relative abundance of genera associated with these species showed minor differences by season and facility; the genera Klebsiella and Staphylococcus showed high relative abundance in subway compartments and daycare centers, respectively. Based on our findings, we recommend enhancing management strategies targeting opportunistic pathogenic bacteria related to antibiotic resistance in the air of subway compartments and daycare centers.

Characterization of pathogenic microbiome on removable prostheses with different levels of cleanliness using 2bRAD-M metagenomic sequencing

ABSTRACT Background The microbiomes on the surface of unclean removable prostheses are complex and yet largely underexplored using metagenomic sequencing technology. Objectives To characterize the microbiome of removable prostheses with different levels of cleanliness using Type IIB Restriction-site Associated DNA for Microbiome (2bRAD-M) sequencing and compare the Microbial Index of Pathogenic Bacteria (MIP) between clean and unclean prostheses. Materials and Methods Ninety-seven removable prostheses were classified into ‘clean’ and ‘unclean’ groups. All prosthesis plaque samples underwent 2bRAD metagenomic sequencing to characterize the species-resolved microbial composition. MIPs for clean and unclean prostheses were calculated based on the sum of the relative abundance of pathogenic bacteria in a microbiome using a reference database that contains opportunistic pathogenic bacteria and disease-associated information. Results Beta diversity analyses based on Jaccard qualitative and Bray-Curtis quantitative distance matrices identified significant differences between the two groups (p < 0.05). There was a significant enrichment of many pathogenic bacteria in the unclean prosthesis group. The MIP for unclean prostheses (0.47 ± 0.25) was significantly higher than for clean prostheses (0.37 ± 0.29), p = 0.029. Conclusions The microbial community of plaque samples from ‘unclean’ prostheses demonstrated compositional differences compared with ‘clean’ prostheses. In addition, the pathogenic microbiome in the ‘unclean’ versus ‘clean’ group differed.

Microbial Composition and Diversity of High-demand Street-vended Foods in Ecuador

Developing countries such as Ecuador carry a heavy food safety burden but reports on the microbiological quality of their foods are scarce. In this investigation, the microbial diversity of 10 high-risk and mass-consumption street-vended foods including bolones, encebollado, food dressings, ceviche, chopped fruits, fruit juices, fruit salads, cheese, raw chicken, and ground beef in Quito, Guayaquil, and Cuenca, three major population centers in Ecuador, were evaluated using 16S rRNA gene High Throughput Sequencing. In total, 1,840 amplicon sequence variants (ASVs) were classified into 23 phyla, 253 families, 645 genera, and 829 species. In the tested food samples, Proteobacteria and Firmicutes were the most abundant phyla accounting for 97.41% of relative abundance (RA). At genus level, 10 dominant genera were identified: Acinetobacter (12.61% RA), Lactococcus (12.08% RA), Vibrio (8.23% RA), Weissella (7.43% RA), Aeromonas (6.18% RA), Photobacterium (6.32% RA), Pseudomonas (3.92% RA), Leuconostoc (3.51% RA), Klebsiella (3.49% RA), and Cupriavidus (2.86% RA). The highest microbial diversity indices were found in raw chicken, encebollados, fruit salads, and fruit juices from Guayaquil and Cuenca. From sampled foods, 29 species were classified as food spoilage bacteria and 24 as opportunistic pathogenic bacteria. Two groups associated with human diseases were identified, including 11 enteric species and 26 species of fecal bacteria. The occurrence of recognized and opportunistic pathogenic bacteria, as well as enteric and fecal microorganisms, in the street-vended foods indicated extensive risks for the consumers’ health. This study demonstrated the application of culture-independent amplicon sequencing in providing a more comprehensive view of microbial safety for street-vended food, which could be a useful tool to facilitate the control of foodborne diseases.

Microbiological risk assessment and resistome analysis from shotgun metagenomics of bovine colostrum microbiome

Colostrum is known for its nutraceutical qualities, probiotic attributes, and health benefits. The aim of this study was to profile colostrum microbiome from bovine in rural sites of a developing country. The focus was on microbiological safety assessments and antimicrobial resistance, taking into account the risks linked with the consumption of raw colostrum. Shotgun sequencing was employed to analyze microbiome in raw buffalo and cow colostrum. Alpha and beta diversity analyses revealed increased inter and intra-variability within colostrum samples' microbiome from both livestock species. The colostrum microbiome was mainly comprised of bacteria, with over 90% abundance, whereas fungi and viruses were found in minor abundance. Known probiotic species, such as Leuconostoc mesenteroides, Lactococcus lactis, Streptococcus thermophilus, and Lactobacillus paracasei, were found in the colostrum samples. A relatively higher number of pathogenic and opportunistic pathogenic bacteria were identified in colostrum from both animals, including clinically significant bacteria like Clostridium botulinum, Pseudomonas aeruginosa, Escherichia coli, and Listeria monocytogenes. Binning retrieved 11 high-quality metagenome-assembled genomes (MAGs), with three MAGs potentially representing novel species from the genera Psychrobacter and Pantoea. Notably, 175 antimicrobial resistance genes (ARGs) and variants were detected, with 55 of them common to both buffalo and cow colostrum metagenomes. These ARGs confer resistance against aminoglycoside, fluoroquinolone, tetracycline, sulfonamide, and peptide antibiotics. In conclusion, this study describes a thorough overview of microbial communities in buffalo and cow colostrum samples. It emphasizes the importance of hygienic processing and pasteurization in minimizing the potential transmission of harmful microorganisms linked to the consumption of colostrum.

First Report of Pseudomonas oryzihabitans Causing Walnut Leaf Spot Disease in China.

China ranks first in the production and harvest area of walnut (Juglans regia L.) worldwide. Currently, the poor health and low yield of walnut caused by pathogen infection is of concern. In 2022, severe walnut leaf spot disease was observed on the seedlings of four walnut nurseries (0.08 to 0.23 ha) in Liaocheng, Shandong, China, with an average incidence of 48.6% (from 34.6% to 65.3% on the cultivar Xiangling). From August to October, leaf spots mainly appeared on the edges of the leaflets, and occasionally between veins. The lesions were initially soft and rotten, and then light brown, round to semi-circular. Subsequently, the adjacent lesions fused, and the edges of the leaflets and entire leaflets showed symptoms of browning and wilting. For pathogen isolation, five leaflets with representative symptoms from one of the nurseries were collected and wiped three times with sterile absorbent cotton dipped in 75% alcohol and washed with distilled water. Leaflet pieces at the junction of the lesion and healthy tissues were removed, crushed in a sterile mortar, and soaked in a small amount of distilled water for 10 min. The diseased tissue suspension was streaked on a nutrient agar medium (NA) with a sterile inoculation ring and incubated at 28°C for 24 to 72 h. The bacterial colonies obtained were further cultured on NA. The purified colonies were uniform in shape, round, and yellow, with a raised, shiny surface and smooth margin. The isolates were Gram-negative, and the electron microscope analysis showed that the pathogens were short rods (0.35 to 0.52 × 0.90 to 1.24 μm, average = 0.44 ± 0.05 × 1.08 ± 0.11 μm, n = 25). For bacterial species identification, a single-colony culture was subjected to genomic DNA extraction and gene amplification and sequencing of 16S rRNA, rpoD, and gyrB. The universal primers 27F/1492R (Lane 1991) were used to amplify the 16S rRNA gene and the specific primers 70F/70R and UP-1E/APrU (Yamamoto et al. 2000) were used to amplify the rpoD and gyrB genes, respectively. In the BLAST analysis, the 16S rRNA sequence (GenBank OR195734) of the isolate shared 99% similarity (1409/1410 bp) with Pseudomonas oryzihabitans strain IAM 1568T (AM262973.1), and the rpoD (OR709708) and gyrB (OR709707) sequences showed >98% identity to rpoD (707/717 bp; FN554494.1) and gyrB (787/801 bp; FN554210.1) of P. oryzihabitans strain LMG 7040T. Based on the above results, the isolated bacterium was identified as P. oryzihabitans. For the pathogenicity test, healthy leaflets from 10 two-year-old potted walnut seedlings (cv. Xiangling) were used as inoculation materials. The leaflets were punctured with a sterile inoculation needle of 0.4 mm, and three small holes on each leaflet at an interval of about 5 mm were covered with a piece of sterile cotton. A bacterial suspension (1 ml) at 107 CFU/ml was spread onto the cotton, and wrapped with plastic film for 24 h. Water was used as a negative control. The inoculations were performed five times. Plants were grown outdoors at a daily average temperature of 22°C with relative humidity over 45%. Two days after inoculation, the disease began to develop in the leaflets with similar symptoms to those observed in the field. In contrast, control plants remained healthy and symptomless. Bacteria were reisolated from the inoculated walnut plants, and the morphology and 16S rRNA gene sequences of the isolates were the same as those of the original strains. Since it was discovered as an opportunistic human pathogenic bacterium in the 1970s (Keikha et al. 2019), P. oryzihabitans has also been shown to cause certain plant diseases, such as panicle blight and grain discoloration on rice (Hou et al. 2020), fruit black rot on prickly ash (Liu et al. 2021), and stem and leaf rot on muskmelon (Li et al. 2021). As far as we know, this is the first report of P. oryzihabitans causing walnut leaf spot disease in China. Leaf spot caused by P. oryzihabitans may be a threat to walnut cultivation, and this report of its occurrence is the first step in determining potential spread and effective control measures.

Molecular study of blaVIM and blaIMP genes in Acinetobacter baumannii strains isolated from burn patients in Duhok City, Iraq.

Acinetobacter baumannii (A. baumannii) is an opportunistic pathogenic bacterium mainly associated with hospital acquired infections and in immunocompromised individuals who stay in hospitals for a long time. In recent years, it has become increasingly resistant to many different types of antibiotics. The production of the metallo-beta-lactamase (MBL) enzyme is one of the primary causes of this resistance. This study aimed to detect the presence of MBL genes that belong to the verona integrin metallo-β-lactamase (bla-VIM) and imipenemase (bla-IMP) groups in the isolates of Acinetobacter baumannii from burn patients. One hundred and seventeen (117) isolates of A. baumannii were obtained from patient specimens using traditional methods followed by using the VITEK 2 (BioMérieux, Les Pennes-Mirabeau, France) identification system. Metallo β-lactamases were detected in the imipenem-resistant strains by using imipenem disks on Muller-Hinton agar. The polymerase chain reaction (PCR) technique was utilized to examine 117 isolates for the detection of MBLs encoding genes such as bla-VIM, and bla-IMP. Imipenem resistance was detected in 78.6% of the patients. The PCR assays of the isolates identified bla-VIM-1, bla-VIM-2, bla-IMP-1 and bla-IMP-2 genes at the rates of 17%, 40.1%, 29.9% and 4.2%, respectively. The findings suggest that the majority of A. baumannii isolates harbour one or more of the detected genes, signifying that the production of MBLs plays a pivotal role in resistance mechanisms.

An Assessment of Human Opportunistic Pathogenic Bacteria on Daily Necessities in Nanjing City during Plum Rain Season.

The plum rain season is a special climatic phenomenon in east Asia, which is characterized by persistent rainfall, a high temperature, and humidity, providing suitable environmental conditions for certain pathogenic bacteria, thus increasing the incidence of respiratory, gastrointestinal, and urinary diseases. However, studies on human opportunistic pathogenic bacteria communities during the plum rain season are still limited. In this study, the characteristics of human opportunistic pathogenic bacterial communities on daily necessities during the non-plum and plum rain seasons were investigated using high-throughput sequencing technology. The results revealed that the relative abundance of human opportunistic pathogenic bacteria was higher in the plum rain season (cotton cloth: 2.469%, electric bicycles: 0.724%, rice: 3.737%, and washbasins: 5.005%) than in the non-plum rain season (cotton cloth: 1.425%, electric bicycles: 0.601%, rice: 2.426%, and washbasins: 4.801%). Both temperature and relative humidity affected human opportunistic pathogenic bacterial communities. Stochastic processes dominated the assembly process of human opportunistic pathogenic bacterial communities, and undominated processes prevailed. The stability of the co-occurrence network was higher in the non-plum rain season than that in the plum rain season. In addition, the proportion of deterministic processes showed the same trend as the complexity of the co-occurrence network.

Boosting Fitness Costs Associated with Antibiotic Resistance in the Gut: On the Way to Biorestoration of Susceptible Populations.

The acquisition and expression of antibiotic resistance implies changes in bacterial cell physiology, imposing fitness costs. Many human opportunistic pathogenic bacteria, such as those causing urinary tract or bloodstream infections, colonize the gut. In this opinionated review, we will examine the various types of stress that these bacteria might suffer during their intestinal stay. These stresses, and their compensatory responses, probably have a fitness cost, which might be additive to the cost of expressing antibiotic resistance. Such an effect could result in a disadvantage relative to antibiotic susceptible populations that might replace the resistant ones. The opinion proposed in this paper is that the effect of these combinations of fitness costs should be tested in antibiotic resistant bacteria with susceptible ones as controls. This testing might provide opportunities to increase the bacterial gut stress boosting physiological biomolecules or using dietary interventions. This approach to reduce the burden of antibiotic-resistant populations certainly must be answered empirically. In the end, the battle against antibiotic resistance should be won by antibiotic-susceptible organisms. Let us help them prevail.

Motility of Acinetobacter baumannii: regulatory systems and controlling strategies.

Acinetobacter baumannii is a Gram-negative opportunistic zoonotic pathogenic bacterium that causes nosocomial infections ranging from minor to life-threatening. The clinical importance of this zoonotic pathogen is rapidly increasing due to the development of multiple resistance mechanisms and the synthesis of numerous virulence factors. Although no flagellum-mediated motility exists, it may move through twitching or surface-associated motility. Twitching motility is a coordinated multicellular movement caused by the extension, attachment, and retraction of type IV pili, which are involved in surface adherence and biofilm formation. Surface-associated motility is a kind of movement that does not need appendages and is most likely driven by the release of extra polymeric molecules. This kind of motility is linked to the production of 1,3-diaminopropane, lipooligosaccharide formation, natural competence, and efflux pump proteins. Since A. baumannii's virulence qualities are directly tied to motility, it is possible that its motility may be used as a specialized preventative or therapeutic measure. The current review detailed the signaling mechanism and involvement of various proteins in controlling A. baumannii motility. As a result, we have thoroughly addressed the role of natural and synthetic compounds that impede A. baumannii motility, as well as the underlying action mechanisms. Understanding the regulatory mechanisms behind A. baumannii's motility features will aid in the development of therapeutic drugs to control its infection. KEY POINTS: • Acinetobacter baumannii exhibits multiple resistance mechanisms. • A. baumannii can move owing to twitching and surface-associated motility. • Natural and synthetic compounds can attenuate A. baumannii motility.

Enteric α-Defensin Contributes to Recovery of Radiation-Induced Intestinal Injury by Modulating Gut Microbiota and Fecal Metabolites.

The effect of ionizing radiation on the gastrointestinal tract is a common complication of abdominal and pelvic radiotherapy. However, the pathological features of radiation enteropathy and its effective medical intervention regimen is still a global challenge. Here, we explored the role and mechanism of enteric alpha-defensins (EαDs) in protecting against radiation enteropathy. To address this, we utilized EαDs-deficiency mice, in which the matrix metallopeptidase 7 to activate Paneth cell α-defensins was knockout (KO) mice, and the complementary wild-type (WT) control mice for this study. Remarkably, the KO mice were more susceptible to 5.0 Gy total-body irradiation, resulting in worse clinic scores and lower survival rate, compared with the wild-type mice. Histological examination indicated that the KO mice were subjected to slow recovery of intestinal villus and mucosa function, characterized by the reduced expression of TFF3, Glut1 and Muc2. In addition, compared with the wild-type controls, the KO mice experienced serious inflammation response in intestinal tissue, indicated by the remarkably increased expression level of IL-1β, IL-6 and IL-12. Using high-throughput sequencing analysis, we found that the intestinal bacterial community of the KO mice was more prone to dysbiosis than that of the WT mice, with significantly increased abundance of opportunistic pathogenic bacteria, such as Streptococcus sp. and Escherichia-Shigella sp., whereas remarkably decreased probiotics harboring Lactobacillus sp., Desulfovibrio sp. etc. Fecal metabolomics analysis indicated that the relative abundance of 31 metabolites arose significantly different between WT and KO mice on day 10 after radiation exposure. A subset of differential metabolites to regulate host metabolism and immunity, such as acetic acid, acetate, butanoic acid, was negatively correlated with the alteration of gut microbiota in the irradiated KO mice. This study provides new insight into EαDs contribution to the recovery of radiation-induced intestinal damage, and suggests a potential novel target to prevent the adverse effects of radiotherapy.

Detection of hypervirulent and classical type of Klebsiella pneumoniae and screening their resistant properties in Erbil city

Background and objective: Klebsiella pneumoniaei s an opportunistic pathogenic bacterium and is considered one of the main causes of nosocomial infection. Hypervirulent K. pneumoniae (hvKp) has emerged as a pathogen of global importance. The current study aimed to determine Extended-spectrum beta-lactamase, carbapenem resistance, and serum bactericidal effect among the clinical isolates and to find the relationship of the above features with antimicrobial resistance. Methods: A total of 90 K. pneumoniae isolates were collected from different clinical specimens. Isolates were diagnosed using routine bacteriological methods and VITEK 2 compact system. Several phenotypic tests including string test, serum resistant, ESBL test, and Modified Carbapenem inactivation method were performed. The antibiotic resistance pattern was compared among ESBL-positive, carbapenem-resistant in both Hypervirulent (hvKp) and classical K. pneumoniae (cKp) isolates. Results: The results revealed that among 90 isolates, 56.7% of the isolates were of classical K. pneumoniae (cKp) type within which 70.6% of them were ESBL positive, 37.3% of them were resistant to carbapenem, and 51% were resistant to serum bactericidal activity. On the other hand, 43.3% were of hvKp type within which 61.5% of them were ESBL positive, 30.8% were carbapenem-resistant and all of the hvKp were resistant to human serum. The rate of antibiotic-resistant among cKp was higher than hvKp isolates. Conclusion: In this study, classical strains were more resistant to antibiotics and the rates of ESBL and Carbapenem resistance were higher compared to hvKp strains. but they were killed by serum bactericidal activities more rapidly.

Celastrol ameliorates experimental autoimmune uveitis through STAT3 targeting and gut microenvironment reprofiling

BackgroundExtensive research has revealed the favorable effects of celastrol (CEL) against various diseases, but the role of CEL in autoimmune uveitis remains unexplored. MethodsWe first assessed the prophylactical and therapeutical effects of CEL on autoimmune uveitis via rat experimental autoimmune uveitis model. After network pharmacology, functional enrichment and molecular docking analyses, we predicted the potential target of CEL and validated its effect on EAU by clinical and histopathological scores, Evans blue staining, immunofluorescence assay and western blotting. Then we evaluated the role of CEL in the gut environment by 16S rRNA sequencing and untargeted metabolomic analysis. ResultsWe confirmed that CEL treatment suppressed the pathological TH17 response, inhibited the migration of inflammatory cells, and preserved the integrity of BRB via targeting STAT3-IL17 pathway. Furthermore, CEL was found to reduce the relative abundance of opportunistic pathogenic bacteria including Clostridium_sensu_stricto_1, Parasutterella and GCA-900066575, and enrich the relative abundance of beneficial Oscillospirales and Ruminococcus_torques_group in EAU rats by fecal 16S rRNA sequencing. Meanwhile, CEL treatment reshaped the gut metabolites in the EAU rats by increasing the relative concentrations of cholic acid, progesterone and guggulsterone, and decreasing the relative levels of isoproterenol, creatinine and phenylacetylglutamine. ConclusionsCEL exerts its ameliorative effects on the experimental autoimmune uveitis through the dual mechanisms of targeting STAT3 and reprofiling the gut microenvironment.

Antimicrobial Protein LECT2-b Helps Maintain Gut Microbiota Homeostasis via Selectively Targeting Certain Pathogenic Bacteria.

Antimicrobial peptides/proteins (AMPs) constitute a critical component of gut immunity in animals, protecting the gut from pathogenic bacteria. However, the interactions between AMPs and gut microbiota remain elusive. In this study, we show that leukocyte-derived chemotaxin-2 (LECT2)-b, a recently discovered AMP, helps maintain gut homeostasis in grass carp (Ctenopharyngodon idella), one of the major farmed fish species globally, by directly regulating the gut microbiota. Knockdown of LECT2-b resulted in dysregulation of the gut microbiota. Specifically, LECT2-b deficiency led to the dominance of Proteobacteria, consisting of proinflammatory bacterial species, over Firmicutes, which includes anti-inflammatory bacteria. In addition, the opportunistic pathogenic bacteria genus Aeromonas became the dominant genus replacing the probiotic bacteria Lactobacillus and Bacillus. Further analysis revealed that this effect was due to the direct and selective inhibition of certain pathogenic bacterial species by LECT2-b. Moreover, LECT2-b knockdown promoted biofilm formation by gut microbiota, resulting in tissue damage and inflammation. Importantly, LECT2-b treatment alleviated the negative effects induced by LECT2-b knockdown. These findings highlight the crucial role of LECT2-b in maintaining the gut microbiota homeostasis and mucosal health. Overall, our study provides important data for understanding the roles of AMPs in the regulation of gut homeostasis in animals.

A skin microbiome model with AMP interactions and analysis of quasi-stability vs stability in population dynamics

The skin microbiome plays an important role in the maintenance of a healthy skin. It is an ecosystem, composed of several species, competing for resources and interacting with the skin cells. Imbalance in the cutaneous microbiome, also called dysbiosis, has been correlated with several skin conditions, including acne and atopic dermatitis. Generally, dysbiosis is linked to colonization of the skin by a population of opportunistic pathogenic bacteria. Treatments consisting in non-specific elimination of cutaneous microflora have shown conflicting results. In this article, we introduce a mathematical model based on ordinary differential equations, with 2 types of bacteria populations (skin commensals and opportunistic pathogens) and including the production of antimicrobial peptides to study the mechanisms driving the dominance of one population over the other. By using published experimental data, assumed to correspond to the observation of stable states in our model, we reduce the number of parameters of the model from 13 to 5. We then use a formal specification in quantitative temporal logic to calibrate our model by global parameter optimization and perform sensitivity analyses. On the time scale of 2 days of the experiments, the model predicts that certain changes of the environment, like the elevation of skin surface pH, create favorable conditions for the emergence and colonization of the skin by the opportunistic pathogen population, while the production of human AMPs has non-linear effect on the balance between pathogens and commensals. Surprisingly, simulations on longer time scales reveal that the equilibrium reached around 2 days can in fact be a quasi-stable state followed by the reaching of a reversed stable state after 12 days or more. We analyze the conditions of quasi-stability observed in this model using tropical algebraic methods, and show their non-generic character in contrast to slow-fast systems. These conditions are then generalized to a large class of population dynamics models over any number of species.