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Journal of Clinical Microbiology Aug 2004This paper presents Etest determinations of MICs of selected antimicrobial agents for 76 isolates of Bacillus anthracis chosen for their diverse histories and 67, 12,... (Comparative Study)
Comparative Study
MICs of selected antibiotics for Bacillus anthracis, Bacillus cereus, Bacillus thuringiensis, and Bacillus mycoides from a range of clinical and environmental sources as determined by the Etest.
This paper presents Etest determinations of MICs of selected antimicrobial agents for 76 isolates of Bacillus anthracis chosen for their diverse histories and 67, 12, and 4 cultures, respectively, of its close relatives B. cereus, B. thuringiensis, and B. mycoides derived from a range of clinical and environmental sources. NCCLS breakpoints are now available for B. anthracis and ciprofloxacin, penicillin, and tetracycline; based on these breakpoints, the B. anthracis isolates were all fully susceptible to ciprofloxacin and tetracycline, and all except four cultures, three of which had a known history of penicillin resistance and were thought to originate from the same original parent, were susceptible to penicillin. Based on NCCLS interpretive standards for gram-positive and/or aerobic bacteria, all cultures were susceptible to amoxicillin-clavulanic acid and gentamicin and 99% (one with intermediate sensitivity) of cultures were susceptible to vancomycin. No group trends were apparent among the different categories of B. cereus (isolates from food poisoning incidents and nongastrointestinal infections and food and environmental specimens not associated with illness). Differences between B. anthracis and the other species were as expected for amoxicillin and penicillin, with all B. anthracis cultures, apart from the four referred to above, being susceptible versus high proportions of resistant isolates for the other three species. Four of the B. cereus and one of the B. thuringiensis cultures were resistant to tetracycline and a further six B. cereus and one B. thuringiensis cultures fell into the intermediate category. There was a slightly higher resistance to azithromycin among the B. anthracis strains than for the other species. The proportion of B. anthracis strains fully susceptible to erythromycin was also substantially lower than for the other species, although just a single B. cereus strain was fully resistant. The Etest compared favorably with agar dilution in a subsidiary test set up to test the readings, and it compared with other published studies utilizing a variety of test methods.
Topics: Anti-Bacterial Agents; Bacillus anthracis; Bacillus cereus; Bacillus thuringiensis; Foodborne Diseases; Humans; Microbial Sensitivity Tests
PubMed: 15297508
DOI: 10.1128/JCM.42.8.3626-3634.2004 -
Blood Transfusion = Trasfusione Del... Sep 2021The aim of the study was to determine if periodontitis, which often causes transient bacteraemia, associates with viable bacteria in standard blood donations.
BACKGROUND
The aim of the study was to determine if periodontitis, which often causes transient bacteraemia, associates with viable bacteria in standard blood donations.
MATERIALS AND METHODS
This was a cross-sectional study of 60 self-reported medically healthy blood donors aged over 50 years. According to standard procedures, whole blood was separated by fractionation into plasma, buffy-coat, and red blood cell (RBC)-fractions. The buffy-coat was screened for bacterial contamination using BacT/ALERT. Samples from plasma and RBC-fractions were incubated anaerobically and aerobically at 37°C for 7 days on trypticase soy blood agar (TSA). For identification, colony polymerase chain reaction was performed using primers targeting 16S rDNA.
RESULTS
From 62% of the donors with periodontitis, bacterial growth was observed on at least 1 out of 4 plates inoculated with plasma or RBCs, whereas only 13% of plates inoculated with plasma or RBCs from periodontally healthy controls yielded bacterial growth (relative risk 6.4, 95% CI: 2.1; 19.5; p=0.0011). None of the donors tested positive for bacterial contamination using BacT/ALERT. Cutibacterium acnes was found in 31% of the donations from donors with periodontitis and in 10% of the donations from periodontally healthy donors. In addition, Staphylococcus species, Bacillus mycoides, Aggregatibacter aphrophilus, and Corynebacterium kroppenstedtii were detected.
DISCUSSION
Periodontitis increased the risk of bacterial contamination of blood products. Contaminating bacteria are often associated with the RBC-fraction. As the BacT/ALERT test is generally performed on platelet products, routine screening fails to detect many occurrences of viable bacteria in the RBC-fraction.
Topics: Aged; Bacteria; Blood Donors; Blood Platelets; Cross-Sectional Studies; Erythrocytes; Humans; Periodontitis
PubMed: 33539285
DOI: 10.2450/2021.0336-20 -
Frontiers in Plant Science 2021Decomposed organic materials, in combination with plant growth-promoting bacteria (PGPB), are environmentally friendly and reduce synthetic fertilizer use in rice...
Decomposed organic materials, in combination with plant growth-promoting bacteria (PGPB), are environmentally friendly and reduce synthetic fertilizer use in rice production. A bio-organic fertilizer (BoF) was prepared using kitchen waste (79%), chita-dhan (unfilled rice grain) biochar (15%), rock phosphate (5%), and a consortium of 10 PGPB (1%) to supplement 30% nitrogen and to replace triple superphosphate (TSP) fertilizer in rice production with an improvement of soil health. PGPB were local isolates and identified using 16S ribosomal RNA partial gene sequences as , sp., , and spp. Isolates could fix N by 0.7-1.4 g kg, solubilize 0.1-1.2 g kg phosphate, and produce 0.1-40 g kg indoleacetic acid. The performance of BoF was evaluated by 16 field experiments and 18 farmers' field demonstration trials during the year 2017-2020 in different parts of Bangladesh. Performances of BoF were evaluated based on control (T), full synthetic fertilizer dose of N, P, and K (T), BoF (2 t ha) + 70% N as urea + 100% K as muriate of potash (T), 70% N as urea + 100% P as TSP + 100% K as muriate of potash (T), and 2 t ha BoF (T) treatments. At the research station, average grain yield improved by 10-13% in T compared with T treatment. Depending on seasons, higher agronomic N use efficiency (19-30%), physiological N use efficiency (8-18%), partial factor productivity (PFP) (114-150%), recovery efficiency (RE) (3-31%), N harvest index (HI) (14-24%), agronomic P use efficiency (22-25%), partial factor productivity of P (9-12%), ARE (15-23%), and HI (3-6%) were obtained in T compared with T treatment. Research results were reflected in farmers' field, and significant ( < 0.05) higher plant height, tiller, panicle, grain yield, partial factor productivity of N and P were obtained in the same treatment. Application of BoF improved soil organic carbon by 6-13%, along with an increased number of PGPB as compared with full synthetic fertilizer dose. In conclusion, tested BoF can be considered as a green technology to reduce 30% synthetic N and 100% TSP requirements in rice production with improved soil health.
PubMed: 33833767
DOI: 10.3389/fpls.2021.602052 -
ISME Communications Sep 2022Protists' selective predation of bacterial cells is an important regulator of soil microbiomes, which might influence the success of bacterial releases in soils. For...
Protists' selective predation of bacterial cells is an important regulator of soil microbiomes, which might influence the success of bacterial releases in soils. For instance, the survival and activity of introduced bacteria can be affected by selective grazing on resident communities or the inoculant, but this remains poorly understood. Here, we investigated the impact of the introduction in the soil of two protozoa species, Rosculus terrestris ECOP02 and/or Cerocomonas lenta ECOP01, on the survival of the inoculants Bacillus mycoides M2E15 (BM) or B. pumilus ECOB02 (BP). We also evaluated the impact of bacterial inoculation with or without protozoan addition on the abundance and diversity of native soil bacterial and protist communities. While the addition of both protozoa decreased the survival of BM, their presence contrarily increased the BP abundance. Protists' selective predation governs the establishment of these bacterial inoculants via modifying the soil microbiome structure and the total bacterial abundance. In the BP experiment, the presence of the introduced protozoa altered the soil community structures and decreased soil bacterial abundance at the end of the experiment, favouring the invader survival. Meanwhile, the introduced protozoa did not modify the soil community structures in the BM experiment and reduced the BM + Protozoa inoculants' effect on total soil bacterial abundance. Our study reinforces the view that, provided added protozoa do not feed preferentially on bacterial inoculants, their predatory behaviour can be used to steer the soil microbiome to improve the success of bacterial inoculations by reducing resource competition with the resident soil microbial communities.
PubMed: 37938668
DOI: 10.1038/s43705-022-00166-9 -
Microorganisms Dec 2020The phylogeny, identification, and characterization of 33 isolates originating from 17 agricultural soils from 11 countries were analyzed on the basis of whole genome...
The phylogeny, identification, and characterization of 33 isolates originating from 17 agricultural soils from 11 countries were analyzed on the basis of whole genome sequencing. Phylogenetic analyses revealed all isolates are divided into six groups, which follows the generally accepted phylogenetic division of isolates. Four different identification methods resulted in a variation in the identity of the isolates, as none of the isolates were identified as the same species by all four methods-only the recent identification method proposed directly reflected the phylogeny of the isolates. This points to the importance of describing the basis and method used for the identification. The presence and percent identity of the protein product of 19 genes potentially involved in pathogenicity divided the 33 isolates into groups corresponding to phylogenetic division of the isolates. This suggests that different pathotypes exist and that it is possible to differentiate between them by comparing the percent identity of proteins potentially involved in pathogenicity. This also reveals that a basic link between phylogeny and pathogenicity is likely to exist. The geographical distribution of the isolates is not random: they are distributed in relation to their division into the six phylogenetic groups, which again relates to different ecotypes with different temperature growth ranges. This means that we find it easier to analyze and understand the results obtained from the 33 isolates in a phylogenetic, patho-type and ecotype-oriented context, than in a context based on uncertain identification at the species level.
PubMed: 33353020
DOI: 10.3390/microorganisms8122028 -
Computational and Structural... 2022In nature, bacteria frequently reside in differentiated communities or biofilms. These multicellular communities are held together by self-produced polymers that allow...
In nature, bacteria frequently reside in differentiated communities or biofilms. These multicellular communities are held together by self-produced polymers that allow the community members to adhere to the surface as well as to neighbor bacteria. Here, we report that exopolysaccharides prevent from co-aggregating with a distantly related bacterium , while maintaining their role in promoting self-adhesion and co-adhesion with phylogenetically related bacterium, The defensive role of the exopolysaccharides is due to the specific regulation of bacillaene. Single cell analysis of biofilm and free-living bacterial cells using imaging flow cytometry confirmed a specific role for the exopolysaccharides in microbial competition repelling Unlike exopolysaccharides, the matrix protein TasA induced bacillaene but inhibited the expression of the biosynthetic clusters for surfactin, and therefore its overall effect on microbial competition during floating biofilm formation was neutral. Thus, the exopolysaccharides provide a dual fitness advantage for biofilm-forming cells, as it acts to promote co-aggregation of related species, as well as, a secreted cue for chemical interference with non-compatible partners. These results experimentally demonstrate a general assembly principle of complex communities and provides an appealing explanation for how closely related species are favored during community assembly. Furthermore, the differential regulation of surfactin and bacillaene by the extracellular matrix may explain the spatio-temporal gradients of antibiotic production within biofilms.
PubMed: 34976308
DOI: 10.1016/j.csbj.2021.11.043 -
Heliyon Dec 2022Castor ( L.) is cultivated for seed oil and to feed (leaves) Eri silkworm, (Donovan) Hutt. blight affects castor cultivation resulting substantial yield loss (∼30%)....
BACKGROUND
Castor ( L.) is cultivated for seed oil and to feed (leaves) Eri silkworm, (Donovan) Hutt. blight affects castor cultivation resulting substantial yield loss (∼30%). Uses of synthetic fertilizers and agrochemicals for disease management have serious concerns as the castor leaves are fed to eri silkworms for rearing. Application of plant growth promoting rhizobacteria for disease suppression and to enhance plant growth will be a healthier choice in castor cultivation. The aim of this study was to assess the efficacy of blight disease suppression by native rhizobacteria isolated from wasteland castor and their ability on plant growth promotion.
METHODOLOGY
We isolated 50 bacterial antagonists from castor rhizosphere using the dilution plate method and evaluated their antagonistic activity against the castor blight pathogen, . Based on antimicrobial bioassay and plant growth promotion (PGP) traits (phosphate solubilization, ACC deaminase activities, production of IAA, GA, HCN, NH and siderophore), salt and acid tolerance; we have chosen ten potential isolates and identified them through 16SrRNA gene sequencing and analysis. Disease suppression and plant growth studies were evaluated in pot experiments.
RESULTS AND CONCLUSION
Three isolates namely, (LRP-2), (HF-1) and (UR-6) showed potential antagonistic activities and PGP traits which were selected for disease suppression and PGP studies. Application of PGPR consortia (LRP-2+HF-1) could suppress the plants from infection in challenged inoculation. Mix inoculation of LRP-2 and UR-6 showed synergistic effect and enhanced plant growth in pot experiments. Combinations of (LRP-2), (HF-1) and (UR-6) can be applied as bio-control and bio-fertilizer formulation to protect castor from blight and also to enhance plant growth.
PubMed: 36466578
DOI: 10.1016/j.heliyon.2022.e11886 -
Plants (Basel, Switzerland) Mar 2023The heavy use of mineral fertilizers causes imbalances in the biological processes that take place in soil. Therefore, it is necessary to develop more effective...
The heavy use of mineral fertilizers causes imbalances in the biological processes that take place in soil. Therefore, it is necessary to develop more effective fertilizers or fertilizer complexes that ensure agricultural productivity and soil conservation. There is currently a lack of knowledge regarding the effectiveness of biologically enriched, complex mineral fertilizers for spring barley fertilization. The hypothesis of this study was that bacteria-enriched (, , , and ), complex mineral fertilizers (NPK) have significant impacts on the yield and potential for economic use of spring barley. Experimental studies were carried out for three years (2020-2022) with sandy loam soil in southern Lithuania. Four different spring barley fertilization scenarios (SCs) were investigated. In SC-1 (control), complex mineral fertilizer (NPK) was not applied. In the other SCs, spring barley was sown with a drill and fertilizers were incorporated locally during the sowing operation: fertilization scenario SC-2 used 300 kg ha, SC-3 used 150 kg ha preceded by a bacteria-inoculated complex mineral fertilizer (NPK), and SC-4 used 300 kg ha with the same bacterial complex. The results showed that the bacterial inoculant increased the efficiency of the mineral fertilizer and had an effect on plant growth in barley. For three consecutive years in the same plots, the bacterial inoculant showed significant positive effects on grain yield (changes of 8.1% in 2020, 6.8% in 2021, and 17.3% in 2022 between SC-2 and SC-4). Comparing the several different fertilizer scenarios from an economic point of view, it was observed that the highest profit per hectare was obtained with SC-4 in all three years of the study. Comparing SC-4 and SC-2, an increase of 13.7% was observed in 2020, followed by 9.1% and 41.9% in 2021 and in 2022, respectively. This study will be useful for farmers, biological inoculant manufacturers, and scientists researching the effectiveness of biological inoculants for growing agricultural crops. We found that it is possible to increase the yield of barley (7-17%) using the same rate of mineral fertilization by enriching it with bacterial inoculants. Further studies should be conducted to determine the effects of the bacterial inoculant on crop yield and soil over a period longer than 3 years.
PubMed: 36986916
DOI: 10.3390/plants12061227 -
Current Research in Microbial Sciences Dec 2021Organic farming is an eco-friendly and sustainable farming practice that enhances soil fertility and helps in improving soil quality. But with the commencement of more...
Organic farming is an eco-friendly and sustainable farming practice that enhances soil fertility and helps in improving soil quality. But with the commencement of more sophisticated advances in agricultural techniques, organic farming has gradually become limited in the world. Culture-dependent plant growth-promoting bacterial isolates were isolated from the bulk and rhizospheric soil, of the native high yielding pole type organic pea ( L.) cultivar of Dentam, West Sikkim, India. Based on the 16S rRNA gene sequencing identification of these isolates, it was found that from the bulk soil, Actinobacteria (58%) was the dominant phyla followed by Firmicutes (28%), and Proteobacteria (14%). In the rhizospheric soil it was dominated by Proteobacteria (56%), followed by Firmicutes (33%), and Bacteriodetes (11%). A total of 40 bacterial isolates were initially screened for the plant growth-promoting (PGP) activity and out of them only four bacterial isolates i.e., P8, s DP2, PP3, and PP10 with accession numbers MN589697, MN559516, MN519462 and MN589696 respectively were found to possess higher PGP activity (i.e. phosphorous, potassium solubilization and nitrogen-fixing activity) as compared to the other bacteria present in the soil. Based on the indole-3-acetic acid (IAA) quantitative assay and siderophore production assay, it was found that (MN589697) produced the highest IAA (65.5 µg mL) and siderophore (71%) when compared with the other isolates. The statistical correlation suggests that pH and available phosphorus were the strongest influencing factors for the distribution of Proteobacteria in the rhizospheric soil. The results indicate that these isolates can be potential plant growth promoter under the agro-climatic conditions of Sikkim, India. To the best of our knowledge the present study is the first report of its kind and showcases significant findings pertaining to the assessment of diversity, isolation and identification of plant growth-promoting rhizobacteria of organic pea grown in Sikkim.
PubMed: 34841358
DOI: 10.1016/j.crmicr.2021.100068 -
Archives of Microbiology Oct 2012Bacillus mycoides is a sporogenic Gram-positive soil bacillus of the B. cereus group. This bacillus, which forms hyphal colonies, is composed of cells connected in...
Bacillus mycoides is a sporogenic Gram-positive soil bacillus of the B. cereus group. This bacillus, which forms hyphal colonies, is composed of cells connected in filaments that make up bundles and turn clock- or counterclockwise depending on the strain. A thick peptidoglycan wall gives the rod cells of these bacilli strength and shape. One approach used to study peptidoglycan neoformation in Gram positives exploits the binding properties of antibiotics such as vancomycin and ramoplanin to nascent peptidoglycan, whose localization in the cell is monitored by means of a fluorescent tag. When we treated B. mycoides strains with BODIPY-vancomycin, we found the expected accumulation of fluorescence at the midcell septa and localization along the cell sidewall in small foci distributed quite uniformly. Intense fluorescence was also observed at the poles of many cells, more clearly visible at the outer edges of the cell chains. The unusual abundance of peptidoglycan intermediates at the cell poles after cell separation suggests that the construction process of this structure is different from that of B. subtilis, in which the free poles are rarely reactive to vancomycin.
Topics: Bacillus; Bacillus cereus; Cell Wall; Peptidoglycan; Staining and Labeling; Vancomycin
PubMed: 22773111
DOI: 10.1007/s00203-012-0830-1