Microorganisms that display unique biotechnological characteristics are usually selected for industrial applications. Bacillus cereus NWUAB01 was isolated from a mining soil and its heavy metal ...resistance was determined on Luria-Bertani agar. The biosurfactant production was determined by screening methods such as drop collapse, emulsification and surface tension measurement. The biosurfactant produced was evaluated for metal removal (100 mg/L of each metal) from contaminated soil. The genome of the organism was sequenced using Illumina Miseq platform. Strain NWUAB01 tolerated 200 mg/L of Cd and Cr, and was also tolerant to 1000 mg/L of Pb. The biosurfactant was characterised as a lipopeptide with a metal-complexing property. The biosurfactant had a surface tension of 39.5 mN/m with metal removal efficiency of 69%, 54% and 43% for Pb, Cd and Cr respectively. The genome revealed genes responsible for metal transport/resistance and biosynthetic gene clusters involved in the synthesis of various secondary metabolites. Putative genes for transport/resistance to cadmium, chromium, copper, arsenic, lead and zinc were present in the genome. Genes responsible for biopolymer synthesis were also present in the genome. This study highlights biosurfactant production and heavy metal removal of strain NWUAB01 that can be harnessed for biotechnological applications.
This study was done to identify pesticide-biodegrading microorganisms and to characterize degradation rates. Bacillus safensis strain FO-36b
, Bacillus subtilis subsp. inaquosorum strain KCTC13429
, ...and Bacillus cereus strain ATCC14579
were isolated from pesticide-polluted soil in Sudan, separately incubated with each pesticide with periodic samples drawn for GC and GC-MS. Pesticide biodegradation followed a biphasic model. α and β half-lives (days) of chlorpyrifos, malathion, and dimethoate in B. safensis culture were 2.13, 4.76; 2.59, 5.66; and 9.5, 11.0, respectively. Values in B. subtilis and B. cereus cultures were 4.09, 9.45 and 4.33, 9.99 for chlorpyrifos; 2.99, 5.36 and 2.43, 4.71 for malathion; and 9.53, 15.11 and 4.16, 9.27 for dimethoate. No metabolite was detected in B. subtilis cultures, whereas a few were detected from B. safensis and B. cereus cultures. Bacterial efficiency can be ordered as B. safensis > B. subtilis > B. cereus for chlorpyrifos and B. cereus > B. subtilis > B. safensis for malathion and dimethoate.
Aims
Bacillus cereus sensu lato is a complex group of closely related bacteria, which are commonly present in the natural environment and food products. These organisms may cause food poisoning and ...spoilage as well as opportunistic infections. Thus far, their resistance to selected antibiotics has been explored only in part, especially in the context of strain source. Therefore, our goal was to compare the resistance of B. cereus sl from milk (environment with the potential impact of antibiotics) with strains from soil and pepper (environment without contact with antibiotics) in relation to their origin, toxicity and phylogenetic relationships.
Methods and results
Antibiotic resistance of B. cereus sl was assessed by determining their minimal inhibitory concentrations (MICs) followed by statistical analyses. The phylogeny of the bacteria was investigated by multilocus sequence typing, and toxicity was determined with quantitative reverse‐transcription real‐time PCR. We found that the isolates from milk were more often multiresistant and exhibited a common resistance pattern to β‐lactams but a varied sensitivity to the tested macrolides, clindamycin, tetracycline and vancomycin. Moreover they displayed often significantly higher average MICs; however, their resistance did not correlate with phylogeny, toxicity, or in most cases, with taxonomic affiliation.
Conclusion
We conclude that mainly food matrices may serve as an important reservoir of resistant isolates of B. cereus sl and that the use of antibiotics for the treatment of animal diseases must be carefully monitored as it strongly promotes natural selection for multiresistant strains, even among opportunist pathogens.
Significance and Impact of the Study
The fact that compared to the isolates from natural habitats, nonpathogenic B. cereus sl isolated from food acquire antibiotic resistance faster, should increase producers and consumers awareness and result in protection of public health.
•Multi-metal resistant bacteria was isolated from surface sediment and identified.•Isolate S2-2 and S3-2 could grow till 30 and 55 ppm respectively in metal consortium.•CCD showed 5 g/L sucrose and ...30 g/L yeast extract are optimal for greater EPS yield.•FTIR, TLC and HPLC revealed that EPS are heteropolysaccharide.•Strong emulsifying and flocculation activity was observed with extracted EPS.
The isolation, screening, and identification of multi-metal resistant (Cd, Cu, Pb, and Zn) bacteria from polluted coastal sediment samples were performed. In this study, the isolates S2-2 and S3-2 had higher multi-metal resistance and were identified as Pseudomonas pachastrellae KMS2-2 and Bacillus cereus KMS3-1, respectively. One-variable-at-a time approach suggested that optimum conditions for exopolysaccharides (EPS) production were pH 7.0, incubation time 120 h, 5 g/L sucrose, and 10 g/L yeast extract. Further, optimization by central composite design revealed that the optimum concentrations of sucrose and yeast extract for higher EPS production (8.9 g/L) were 5 g/L, and 30 g/L, respectively. Heteropolysaccharide nature of EPS determined by FTIR, TLC, and HPLC analysis, consist of mannose, rhamnose, glucose, and xylose. In addition, EPS showed strong emulsifying and flocculation activity. Results suggested the potential EPS-producing multi-metal resistant Bacillus cereus KMS3-1 could be used in biotechnological and industrial application, especially metal removal.
Bacillus cereus is the 2nd most frequent bacterial agent responsible for food-borne outbreaks in France and the 3rd in Europe. In addition, local and systemic infections have been reported, mainly ...describing individual cases or single hospital setting. The real incidence of such infection is unknown and information on genetic and phenotypic characteristics of the incriminated strains is generally scarce. We performed an extensive study of B. cereus strains isolated from patients and hospital environments from nine hospitals during a 5-year study, giving an overview of the consequences, sources and pathogenic patterns of B. cereus clinical infections. We demonstrated the occurrence of several hospital-cross-contaminations. Identical B. cereus strains were recovered from different patients and hospital environments for up to 2 years. We also clearly revealed the occurrence of inter hospital contaminations by the same strain. These cases represent the first documented events of nosocomial epidemy by B. cereus responsible for intra and inter hospitals contaminations. Indeed, contamination of different patients with the same strain of B. cereus was so far never shown. In addition, we propose a scheme for the characterization of B. cereus based on biochemical properties and genetic identification and highlight that main genetic signatures may carry a high pathogenic potential. Moreover, the characterization of antibiotic resistance shows an acquired resistance phenotype for rifampicin. This may provide indication to adjust the antibiotic treatment and care of patients.
Korean fermented soybean products, such as doenjang, kochujang, ssamjang, and cho‐kochujang, can harbor foodborne pathogens such as Bacillus cereus sensu lato (B. cereus sensu lato). The aim of this ...study was to characterize the toxin gene profiles, biochemical characteristics, and antibiotic resistance patterns of B. cereus sensu lato strains isolated from Korean fermented soybean products. Eighty‐eight samples of Korean fermented soybean products purchased from retails in Seoul were tested. Thirteen of 26 doenjang samples, 13 of 23 kochujang samples, 16 of 30 ssamjang samples, and 5 of 9 cho‐kochujang samples were positive for B. cereus sensu lato strains. The contamination level of all positive samples did not exceed 4 log CFU/g of food (maximum levels of Korea Food Code). Eighty‐seven B. cereus sensu lato strains were isolated from 47 positive samples, and all isolates carried at least one enterotoxin gene. The detection rates of hblCDA, nheABC, cytK, and entFM enterotoxin genes among all isolates were 34.5%, 98.9%, 57.5%, and 100%, respectively. Fifteen strains (17.2%) harbored the emetic toxin gene. Most strains tested positive for salicin fermentation (62.1%), starch hydrolysis (66.7%), hemolysis (98.9%), motility test (100%), and lecithinase production (96.6%). The B. cereus sensu lato strains were highly resistant to β‐lactam antibiotics such as ampicillin, penicillin, cefepime, imipenem, and oxacillin. Although B. cereus sensu lato levels in Korean fermented soybean products did not exceed the maximum levels permitted in South Korea (<104 CFU/g), these results indicate that the bacterial isolates have the potential to cause diarrheal or emetic gastrointestinal diseases.
Bacillus cereus sensu lato (s. l.) is an ecologically diverse bacterial group of medical and agricultural significance. In this study, I use publicly available genomes and novel bioinformatic ...workflows to characterize the B. cereus s. l. pan-genome and perform the largest phylogenetic and population genetic analyses of this group to date in terms of the number of genes and taxa included. With these fundamental data in hand, I identify genes associated with particular phenotypic traits (i.e., "pan-GWAS" analysis), and quantify the degree to which taxa sharing common attributes are phylogenetically clustered.
A rapid k-mer based approach (Mash) was used to create reduced representations of selected Bacillus genomes, and a fast distance-based phylogenetic analysis of this data (FastME) was performed to determine which species should be included in B. cereus s. l. The complete genomes of eight B. cereus s. l. species were annotated de novo with Prokka, and these annotations were used by Roary to produce the B. cereus s. l. pan-genome. Scoary was used to associate gene presence and absence patterns with various phenotypes. The orthologous protein sequence clusters produced by Roary were filtered and used to build HaMStR databases of gene models that were used in turn to construct phylogenetic data matrices. Phylogenetic analyses used RAxML, DendroPy, ClonalFrameML, PAUP*, and SplitsTree. Bayesian model-based population genetic analysis assigned taxa to clusters using hierBAPS. The genealogical sorting index was used to quantify the phylogenetic clustering of taxa sharing common attributes.
The B. cereus s. l. pan-genome currently consists of ≈60,000 genes, ≈600 of which are "core" (common to at least 99% of taxa sampled). Pan-GWAS analysis revealed genes associated with phenotypes such as isolation source, oxygen requirement, and ability to cause diseases such as anthrax or food poisoning. Extensive phylogenetic analyses using an unprecedented amount of data produced phylogenies that were largely concordant with each other and with previous studies. Phylogenetic support as measured by bootstrap probabilities increased markedly when all suitable pan-genome data was included in phylogenetic analyses, as opposed to when only core genes were used. Bayesian population genetic analysis recommended subdividing the three major clades of B. cereus s. l. into nine clusters. Taxa sharing common traits and species designations exhibited varying degrees of phylogenetic clustering.
All phylogenetic analyses recapitulated two previously used classification systems, and taxa were consistently assigned to the same major clade and group. By including accessory genes from the pan-genome in the phylogenetic analyses, I produced an exceptionally well-supported phylogeny of 114 complete B. cereus s. l. genomes. The best-performing methods were used to produce a phylogeny of all 498 publicly available B. cereus s. l. genomes, which was in turn used to compare three different classification systems and to test the monophyly status of various B. cereus s. l. species. The majority of the methodology used in this study is generic and could be leveraged to produce pan-genome estimates and similarly robust phylogenetic hypotheses for other bacterial groups.
This study investigates the impact of bacteria on arsenic reduction in wheat plants, highlighting the potential of microbe-based eco-friendly strategies for plant growth. In the present study, ...bacterial isolate SPB-10 was survived at high concentration against both form of arsenic (As
3+
and As
5+
). SPB-10 produced 5.2 g/L and 11.3 g/L of exo-polysaccharide at 20 ppm of As
3+
and As
5+
, respectively, whereas qualitative examination revealed the highest siderophores ability. Other PGP attributes such as IAA production were recorded 52.12 mg/L and 95.82 mg/L, phosphate solubilization was 90.23 mg/L and 129 mg/L at 20 ppm of As
3+
and As
5+
, respectively. Significant amount of CAT, APX, and Proline was also observed at 20 ppm of As
3+
and As
5+
in SPB-10. Isolate SPB-10 was molecularly identified as
Bacillus cereus
through 16S rRNA sequencing. After 42 days, wheat plants inoculated with SPB-10 had a 25% increase in shoot length and dry weight, and 26% rise in chlorophyll-a pigment under As
5+
supplemented T4 treatment than control. Reducing sugar content was increased by 24% in T6-treated plants compared to control. Additionally, SPB-10 enhanced the content of essential nutrients (NPK), CAT, and APX in plant’s-leaf under both As
3+
and As
5+
stressed conditions after 42 days. The study found that arsenic uptake in plant roots and shoots decreased in SPB-10-inoculated plants, with the maximum reduction observed in As
5+
treated plants. Bio-concentration factor-BCF was reduced by 90.89% in SPB-10-inoculated treatment T4 after 42 days. This suggests that
Bacillus cereus
-SPB-10 may be beneficial for plant growth in arsenic-contaminated soil.
The present study demonstrates the production and thrombolytic potential of a novel thermostable thiol-dependent fibrinolytic protease by
RSA1. Statistical optimization of different parameters was ...accomplished with Plackett-Burman design and validated further by central composite design with 30.75 U/mL protease production. Precipitation and chromatographic approaches resulted in 33.11% recovery with 2.32-fold purification. The molecular weight of fibrinolytic protease was 40 KDa and it exhibited a broad temperature and pH stability range of 20-80 °C and pH 5-10 with utmost activity at 50 °C and pH 8, respectively. The protease retained its fibrinolytic activity in organic solvents and enhanced the activity in solutions with divalent cations (Mn
, Zn
, and Cu
). The enzyme kinetics revealed K
and V
values of 1.093 mg/mL and 52.39 µg/mL/min, respectively, indicating higher affinity of fibrinolytic activity towards fibrin. Also, complete inhibition of fibrinolytic activity with DFP and a 2-fold increase with DTT and β-mercaptoethanol indicates its thiol-dependent serine protease nature. MALDI-TOF analysis showed 56% amino acid sequence homology with Subtilisin NAT OS =
subsp. natto. The fibrinolysis activity was compared with a commercial thrombolytic agent for its therapeutic applicability, and fibrinolytic protease was found highly significant with absolute blood clot dissolution within 4 h in in vitro conditions. The isolated fibrinolytic protease of
RSA1 is novel and different from other known fibrinolytic proteases with high stability and efficacy, which might have wide medicinal and industrial application as a thrombolytic agent and in blood stain removal, respectively.
Bacillus anthracis is the etiologic agent of anthrax, an acute fatal disease among mammals. It was thought to differ from Bacillus cereus, an opportunistic pathogen and cause of food poisoning, by ...the presence of plasmids pXO1 and pXO2, which encode the lethal toxin complex and the poly-γ-D-glutamic acid capsule, respectively. This work describes a non-B. anthracis isolate that possesses the anthrax toxin genes and is capable of causing a severe inhalation anthrax-like illness. Although initial phenotypic and 16S rRNA analysis identified this isolate as B. cereus, the rapid generation and analysis of a high-coverage draft genome sequence revealed the presence of a circular plasmid, named pBCXO1, with 99.6% similarity with the B. anthracis toxin-encoding plasmid, pXO1. Although homologues of the pXO2 encoded capsule genes were not found, a polysaccharide capsule cluster is encoded on a second, previously unidentified plasmid, pBC218. A/J mice challenged with B. cereus G9241 confirmed the virulence of this strain. These findings represent an example of how genomics could rapidly assist public health experts responding not only to clearly identified select agents but also to novel agents with similar pathogenic potentials. In this study, we combined a public health approach with genome analysis to provide insight into the correlation of phenotypic characteristics and their genetic basis.
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