bacteria

摘要： After the first detection of the gram-negative bacterium,Xylella fastidiosa multiplex in Portugal,in January 2019,a“Demarcated Area”was delimited and an“Action Plan”to control the pathogen has been developed.It is considered one of the greatest threats to plant health worldwide and leads to loss of forests vitality and productivity.The current study was developed till June 2020,with the objective to understand the dimension of the issue worldwide and in Portugal,analyzing the state-of-the-art on the biology,dispersion,symptoms,control and risks associated with this bacterium(Research Phase).In the Prospecting Phase,we collected 5 branches with 5-8 leaves,from the four quadrants of the tree,wrapping and labeling them-so 2,261 samples were collected and sent to the laboratory for analysis.It was possible to determine that the two initial outbreaks were not an isolated case,as 107 additional outbreaks were detected in other places,revealing a much more worrying panorama,requiring further analysis on the real impact of this bacterial strain on the natural environment.By the end of this study the demarcated area covered about 62,000 ha.The most affected species was lavender with 30%of positive outbreaks,followed by gorse with 22%,and rosemary with 11%.Spread of Phillaenus spumarius and X.fastidiosa indicates that insect vector and transport links appear to be dispersal facilitators together with Douro River.As eradication is unfeasible to achieve in the coming years,containment will be the most appropriate strategy.

摘要： Dust emission and wind erosion are widespread phenomena in arid and semi-arid regions,which have far-reaching harmful effects to the environment.This study aimed to use microbial induced carbonate precipitation(MICP)method with Bacillus sphaericus to reduce soil losses that occur in a dust-producing area due to wind erosion in the Ilam Province,Iran.Soil samples at the 0-30 cm depth were used and sterilized in an autoclave for 2 h at 121°C and 103 kPa.Approximately 3 kg soils were weighed and poured in the 35 cm×35 cm×3 cm trays.Different treatments included two levels of B.sphaericus(0.0 and 0.5 OD),three levels of suspension volume(123,264,and 369 mL),two levels of urea-chloride cementation solution(0.0 and 0.5 M),and two levels of bacterial spray(once and twice spray).After 28 d,soil properties such as soil mass loss,penetration resistance,and aggregate stability were measured.The results showed a low soil mass loss(1 g)in F_(14)formulation(twice bacterial spray+264 mL suspension volume+without cementation solution)and a high soil mass loss(246 g)in F_(5) formulation(without bacteria+264 mL suspension volume+0.5 M cementation solution).The highest(42.55%)and the lowest(19.47%)aggregate stabilities were observed in F_(16)and F_(7)formulations,respectively,and the highest penetration resistance(3.328 kg/cm^(2))was observed in F_(18) formulation.According to the final results,we recommended the formulation with twice bacterial spray,0.5 M cementation solution,and 269 mL suspension volume as the best combination for soil surface stabilization.Furthermore,this method is environmentally friendly because it has no adverse effects on soil,water,and plants,thus,it would be an efficient approach to stabilize soil surface.

摘要： This paper reviews three complex interactions between microwave energy and microorganisms (bacteria, fungi, and viruses). The first interaction comprises the detection of viruses within human blood using a 50-Ohm transmission-line vector net-analyzer (typically 0 to 10 dBm @ 2 to 8.5 GHz) where the blood is placed within a test chamber that acts as a non-50-Ohm discontinuity. The second interaction employs 1 to 6.5 W @ 8 to 26 GHz for microwave feed-horn illumination to inactivate microorganisms at an applied power density of 10 to 100 mW-2. The third interaction is within multi-mode microwave ovens, where microorganism cell membrane disruption occurs at a few 100 s of W @ 2.45 GHz and microorganism inactivation between 300 to 1800 W @ 2.45 GHz. Within the first microwave interaction, blood relaxation processes are examined. Whereas in the latter two microwave interactions, the following disruption, and inactivation mechanisms are examined: chemical cellular lysis and, microwave resonant absorption causing cell wall rupture, and thermodynamic analysis in terms of process energy budget and suspension energy density. In addition, oven-specific parameters are discussed.

摘要： To search for a new eco-friendly therapy for infectious disease caused by Escherichia coli,Staphylococcus aureus or Klebsiella oxytoca,we collected the vaginal swabs from healthy women,screened for Lactobacillus and found a strain repressing the growth of pathogenic bacteria.The new isolate was identified as L.gasseri by the colony morphology,Gram staining,biochemical reactions and confirmed by the 16 S rDNA sequencing.The HMV18 strain inhibited the growth of food-borne pathogens such as E.coli,S.aureus and K.oxytoca.The HMV18 strain was sensitive to penicillin,ampicillin,erythromycin,tetracycline and chloramphenicol.The HMV18 strain producedα-hemolysis.Pathological histology of the mice ileum showed that the mucosa,villi,lamina propria and crypt depth remained intact and there was no inflammation or hyperemia in the L.gasseri HMV18 gavaged group.L.gasseri HMV18 could not up-regulate inflammatory cytokines level of plasma.All the results suggested L.gasseri HMV18 is a candidate probiotic to be an additive for food preservation or drug to prevent food-borne diseases.

摘要： The use of enzymes is replacing chemicals in many industrial production processes because of the eco-friendly nature of enzymes which do not generate greenhouse gases and have reduced the demand for energy in industries. To meet the ever-increasing demand for enzymes in many industries and survive the harsh production conditions, microbial sources of enzyme production are the most preferred source for industrial enzyme production because the microbes are readily available, they grow at a very fast rate, and they can be genetically manipulated to produce enzymes which can perform optimally at different industrial production conditions. Microbial enzymes have found so many applications in various industries (textiles, leather, paper and pulp, research and development, pharmaceutical, agriculture, detergent, waste, biorefineries, photography and food industries), thus making them very essential in several industrial production processes. Here in this review, the application of some important microbial enzymes in food industry and the microbial sources for the enzymes are discussed.

摘要： The rise of antibiotic resistance as one of the most serious global public health threats has necessitated the timely clinical diagnosis and precise treatment of deadly bacterial infections.To identify which types and doses of antibiotics remain effective for fighting against multi-drug-resistant pathogens,the development of rapid and accurate antibiotic-susceptibility testing(AST)is of primary importance.Conventional methods for AST in well-plate formats with disk diffusion or broth dilution are both labor-intensive and operationally tedious.The microfluidic chip provides a versatile tool for evaluating bacterial AST and resistant behaviors.In this paper,we develop an operationally simple,3D-printed microfluidic chip for AST which automatically deploys antibiotic concentration gradients and fluorescence intensity-based reporting to ideally reduce the report time for AST to within 5 h.By harnessing a commercially available,digital light processing(DLP)3D printing method that offers a rapid,high-precision microfluidic chip-manufacturing capability,we design and realize the accurate generation of on-chip antibiotic concentration gradients based on flow resistance and diffusion mechanisms.We further demonstrate the employment of the microfluidic chip for the AST of E.coli to representative clinical antibiotics of three classes:ampicillin,chloramphenicol,and kanamycin.The determined minimum inhibitory concentration values are comparable to those reported by conventional well-plate methods.Our proposed method demonstrates a promising approach for realizing robust,convenient,and automatable AST of clinical bacterial pathogens.

摘要： Sea cucumbers play an important role in sediment bioturbation in coral reef and rocky intertidal ecosystems,and bacteria were a commonly-reported component of holothuroid diets.Bacterial community composition in the foregut and hindgut of two common tropical sea cucumbers(Holothuria atra and H.leucospilota)and the ambient surface sediment were investigated using high throughput sequencing based on 16S rRNA gene analysis.A total of 5584 operational taxonomic units(OTUs)were obtained from 25 samples based on a 97%threshold,and more than half of the OTUs(n=3694,66.2%)were shared by the gut contents of two species of sea cucumbers and surrounding sediments.Bacterial richness and diversity insediment samples were signifi cantly higher than those in the gut content samples(P<0.05).Proteobacteria was the predominant phylum in most samples showing 45.69%±8.61%,70.09%±4.03%,45.88%±5.38%,and 55.19%±0.79%reads in the foregut of H.leucospilota,hindgut of H.leucospilota,hindgut of H.atra,and sediment libraries,respectively,but Bacteroidetes was the predominant phylum with the relative content of 34.98%±5.52%in the foregut of H.atra.Among the dominant genera,reads related to the genera Anderseniella,Ilumatobacter,and Ruegeria were detected in all the gut contents and sediment libraries.A comparison of gut bacteria community between the two species of sea cucumbers suggested that H.atra had stronger feeding preference than H.leucospilota,and the same types of microbes escaped digestion of the two sea cucumber species.Obvious diff erent bacterial community composition in the foreguts of the two species of sea cucumbers and the surrounding sediments might result from the animal’s selective feeding for sediment patches.Bacterial community structure in hindgut contents of H.atra and H.leucospilota both diff ered clearly from adjacent sediments,which indicated feeding activity of deposit-feeding sea cucumbers could change the sedimental bacterial composition.In conclusion,from the perspective of bacteria,sea cucumber H.atra and H.leucospilota had diff erent feeding preferences,yet they could both aff ect bacterial composition in sediments by feeding activity.The motivation for selective feeding and sea cucumber-sediment interaction might be explored in the future.

摘要： This paper describes the use of log-linear energy phase-space projections to analyze microwave-assisted inactivation of bacteria and viruses under different fomite conditions within multimode microwave ovens. The ovens are operated at a cavity-magnetron frequency of 2.45 ± 01 GHz. Porous fomites (moist face towels, cotton swabs, kitchen sponges, and scrubbing pads, cigarette filters and N95-like respirators);along with non-porous hard surface syringe fomites are studied. The fomites are classed as dielectric;and absorb microwave energy to varying degrees depending on their complex dielectric permittivity. Microorganism resilience to microwave stress (defined as ≥4 log10 reduction in inactivation) when mapped using iso-volume trend-lines in energy phase-space reveals the persistence imparted by the fomite, and can be mapped between different microwave ovens. Microorganism resilience to thermal microwave-assisted treatment increases from vegetative Gram-negative to vegetative Gram-positive and on to Gram-positive spores. Bacteriophage MS2 and influenza viruses have an intermediate resilience dependency. It is shown that linear-scaled fomite temperature against process time graphs can differentiate between non-thermal and thermal micro-wave-assisted treatment of microorganisms.

摘要： The hospital environment contributes to wound infections. Effects of such infections include prolonged hospitalization, increased morbidity, potential for antibiotics resistance and mortality due to sepsis. An updated knowledge of antibiotics susceptibility profiles of clinical isolates will assist both in choosing the most appropriate antibiotic treatment for wound infections and help in curbing the escalation of drug resistance. Cross sectional hospital based study, analysis of 125 pus samples collected from January 2018 to December 2020 was conducted. Identification and characterization of isolates were performed on the basis of Gram staining, microscopic characteristics, colony characteristic, and biochemical tests using standard microbiological methods. Antibiotic susceptibilities of bacterial isolates were determined by Kirby Bauer disc diffusion. A total of 125 pus samples were studied, 94 (75%) were from male patients, mean age was 38.5 (SD ± 19) years. Single bacterial isolates were recovered from 120 (96%) samples, 67 (53.6%) shows Multiple Drug Resistance (MDR) pattern, 74 (59.2%) were gram negative, the predominant organism isolated was Staphylococcus aureus 46 (36.8%). Gram negative isolates showed high resistance to ampicillin and cephalosporins. Gram positive isolates showed high resistance to erythromycin. Both gram positive and negative were found to be highly susceptible to gentamicin, amikacin, clindamycin, ciprofloxacin and amoxicillin/clavulanic acid. The study showed that Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli are the major bacteria isolated from pus samples. High proportion (53.6%) of the isolates was MDR. In the light of these findings, a change in antibiotic prescription policy is required at this hospital.

摘要： The human microbiota is made up of trillions of bacteria that live in the human being,whereas the microbiome is made up of the microbiota's genes and gene products.Bacteria have long been thought of as pathogens that eventually lead to human illness.Bacteria are increasingly recognized as generally beneficial commensal organisms and hence crucial to proper and healthy human development,thanks to breakthroughs in both cultivation-based approaches and the advent of metagenomics.This relatively new field of medical study has given more information on illnesses such as inflammatory bowel disease,obesity,metabolic and atopic disorders.However,there is a lot we don't know about the complexities of microbe-microbe and microbe-host interactions.Future work targeted at resolving crucial concerns about the early formation of the microbiome,in addition,what determines its dysbiosis,will most likely lead to long-term mitigation of health.In this article,review the research on prenatal and newborn microbiome modulations,the role of maternal and environmental variables on forming the newborn microbiome,and future issues and directions in the exciting new field of metagenomic medicine.

摘要： GAC-sand dual media filters (GSFs) could be used as rapid filters in drinking water treatment.Particle counts and size distribution, heterotrophic bacteria (HPC) in the effluent and the disinfectioncharacteristics, trihalomethanes (THMs) and trihalomethane precursors were used to evaluate effluent safety.GSFs had stable removal efficiencies on particles during stable operations, and better removal efficiency couldbe got on larger particles. Extended subfluidization wash after the traditional backwash was an effectivemethod to improve removal efficiency on particles during filter ripening period, while no effect was found onHPC control. Bacteria could be removed by the filters, while there were chances for more bacteria existed inthe effluent than that of influent. There was little microbial risk in the effluent when judged by HPC afterdisinfection. GSFs could effectively remove THMs, while better removal efficiencies could be achieved onTHM precursors. There were chances for the desorption of previously adsorbed THMs when the concentrationin the influent was low, while the concentration in the effluent was much less than the maximum contaminantlevel in national standard. In sum, more attention should be paid to the bacteria in the effluent, especially whenthere were pathogens in the raw water and during filter ripening period.