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Abstract Background The genus Geobacillus and its associated taxa have been the focal point of numerous thermophilic biotechnological investigations, both at the whole cell and enzyme level. By contrast, comparatively little research has been done on its recently delineated sister genus, Parageobacillus. Here we performed pan-genomic analyses on a subset of publicly available Parageobacillus and Saccharococcus genomes to elucidate their biotechnological potential. Results Phylogenomic analysis delineated the compared taxa into two distinct genera, Parageobacillus and Saccharococcus, with P. caldoxylosilyticus isolates clustering with S. thermophilus in the latter genus. Both genera present open pan-genomes, with the species P. toebii being characterized with the highest novel gene accrual. Diversification of the two genera is driven through the variable presence of plasmids, bacteriophages and transposable elements. Both genera present a range of potentially biotechnologically relevant features, including a source of novel antimicrobials, thermostable enzymes including DNA-active enzymes, carbohydrate active enzymes, proteases, lipases and carboxylesterases. Furthermore, they present a number of metabolic pathways pertinent to degradation of complex hydrocarbons and xenobiotics and for green energy production. Conclusions Comparative genomic analyses of Parageobacillus and Saccharococcus suggest that taxa in both of these genera can serve as a rich source of biotechnologically and industrially relevant secondary metabolites, thermostable enzymes and metabolic pathways that warrant further investigation.

Abstract Barley (Hordeum vulgare) is essential to global food systems and the brewing industry. Its physiological traits and microbial communities determine malt quality. Although microbes influence barley from seed health to fermentation, there is a gap in metagenomic insights during seed storage. Crucially, elucidating the changes in microbial composition associated with barley seeds is imperative for understanding how these fluctuations can impact seed health and ultimately, influence both agricultural yield and quality of barley-derived products. Whole metagenomes were sequenced from eight barley seed samples obtained at different storage time points from harvest to nine months. After binning, 82 metagenome-assembled genomes (MAGs) belonging to 26 distinct bacterial genera were assembled, with a substantial proportion of potential novel species. Most of our MAG dataset (61%) showed over 90% genome completeness. This pioneering barley seed microbial genome retrieval provides insights into species diversity and structure, laying the groundwork for understanding barley seed microbiome interactions at the genome level.

Abstract Background The facultatively anaerobic thermophile Parageobacillus thermoglucosidasius is able to produce hydrogen gas (H2) through the water–gas shift (WGS) reaction. To date this process has been evaluated under controlled conditions, with gas feedstocks comprising carbon monoxide and variable proportions of air, nitrogen and hydrogen. Ultimately, an economically viable hydrogenogenic system would make use of industrial waste/synthesis gases that contain high levels of carbon monoxide, but which may also contain contaminants such as H2, oxygen (O2) and other impurities, which may be toxic to P. thermoglucosidasius. Results We evaluated the effects of synthesis gas (syngas) mimetic feedstocks on WGS reaction-driven H2 gas production by P. thermoglucosidasius DSM 6285 in small-scale fermentations. Improved H2 gas production yields and faster onset towards hydrogen production were observed when anaerobic synthetic syngas feedstocks were used, at the expense of biomass accumulation. Furthermore, as the WGS reaction is an anoxygenic process, we evaluated the influence of O2 perturbation on P. thermoglucosidasius hydrogenogenesis. O2 supplementation improved biomass accumulation, but reduced hydrogen yields in accordance with the level of oxygen supplied. However, H2 gas production was observed at low O2 levels. Supplementation also induced rapid acetate consumption, likely to sustain growth. Conclusion The utilisation of anaerobic syngas mimetic gas feedstocks to produce H2 and the relative flexibility of the P. thermoglucosidasius WGS reaction system following O2 perturbation further supports its applicability towards more robust and continuous hydrogenogenic operation.

The ability of Parageobacillus thermoglucosidasius to produce H2 from CO via the water–gas shift (WGS) reaction makes it a compelling microorganism for biofuels research. Optimizing this process requires evaluating parameters such as pressure. This study aimed to understand how H2 production is affected by increasing CO, N2, and H2 partial pressures to 1.0, 2.0, and 3.0 bar. Increasing CO partial pressure can improve the solubility of the gas in the liquid phase. However, raising CO partial pressure to 3.0 bar had an inhibitory effect, delaying and reducing H2 production. By contrast, increasing N2 and H2 partial pressures to 3.0 bar had positive effects, reaching a H2 production of 9.2 mmol and 130 mmol, respectively. Analysis of the electron balance at the end of the fermentation process showed that the selectivity toward H2 production reached 95%, with the remainder of electrons deriving from CO and glucose directed at organic acid production, mainly acetate, followed by formate.

Background: Refeeding syndrome (RFS) is a life-threatening, underdiagnosed, and under-researched complication in treating children with severe acute malnutrition (SAM). This study aimed to determine the incidence and onset of RFS and identify biochemical abnormalities, clinical signs, and complications associated with RFS development in children, 0–59 months, treated with SAM in a South African public hospital setting. Methods: A retrospective cohort study was performed on hospital medical records of children aged 0–59 months, diagnosed with SAM at Rahima Moosa Mother and Child Hospital, Johannesburg, from 1/10/2014 to 31/12/2018. The onset of RFS among children included in the study was diagnosed based on published criteria for RFS. On admission, children who developed RFS and those who did not were compared concerning biochemistry and clinical signs and symptoms. Results: A total of 148 medical records were retrieved from the hospital archives. The diagnosis of SAM based on the World Health Organization (WHO) definition was confirmed in 126 children who were then included in the study. The median age of the 126 children (63 % male) with confirmed SAM was 11.2 months (P25:7.0 months; P75:17.0 months). The in-hospital mortality rate was 18.2 %, of which 8.7 % were retrospectively diagnosed as having developed RFS during their recorded hospital stay, despite implementing the WHO treatment guidelines for SAM. A significantly higher percentage of the children who developed RFS presented on admission with hypophosphatemia (p = 0.015), hypokalemia (p = 0.001), hyponatremia (p = 0.001), an international normalized ratio (INR) of above 1.7 (p = 0.025), diarrhea (p = 0.042), dehydration (p = 0.029) and urinary tract infection (UTI) (p = 0.041), than those who did not. Children who developed RFS stayed in hospital significantly longer than those who did not (18 vs. 12 days with a p-value of 0.003). Conclusion: In this population of children with SAM treated in a South African public hospital setting, the presence on hospital admission of low levels of electrolytes, elevated INR, dehydration, diarrhea, and UTI was significantly associated with developing RFS. Recognizing these as possible red flags for developing RFS in children admitted with SAM might contribute to improved outcomes and needs further investigation.

Background: The Wits Transplant Unit performed its first paediatric liver transplant in 2005. Initial experiences from the unit were published in 2012 and 2014. Since then, significant progress has been made in capacity-building the unit, improving outcomes and enhancing service delivery. This paper presents a broad overview and update of the unit’s 17-year experience. Methods: We conducted a retrospective review of all paediatric liver transplants performed in Johannesburg from 1 January 2005 to 31 December 2021 with a minimum one-year follow-up. Data were accessed from the Wits Donald Gordon Medical Centre Paediatric Liver Transplant Research Database (University of the Witwatersrand Human Research Ethics approval: M190749). The following data were collected: donor and recipient sociodemographic and clinical characteristics, details of transplant procedures, donor grafts and recipient outcomes (post-operative complications, graft and recipient survival). Results: A total of 270 transplants were performed during the review period. Two thirds of recipients (n=180, 67%) were younger than 5 years at time of transplant and half (n=135, 50%) received a living donor graft. The most common indication for liver transplant was biliary atresia, followed by acute liver failure. Unadjusted recipient survival was 80% (95% CI: 75-85%) at one year, and 68% (95% CI: 59-75%) at five years. Waiting list mortality decreased from 27.3% in 2017 to 5.9% in 2021. One hundred and fifty-four (57.0%) recipients experienced at least one type of intervention requiring surgical complication - the most common being biliary in nature (n = 91; 33.7%). Conclusion: Over last seventeen years, a sustainable paediatric liver transplantation service has been established in Johannesburg. Living donor, split and ABO incompatible liver transplants have been incorporated in response to the severe organ shortage in South Africa. However, our outcomes can be improved. Additionally, a national transplant initiative to coordinate timeous referrals and expand access to liver transplantation for children with severe acute and chronic liver failure is advised.

Abstract Background Pantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by which this occurs among bacteria is through the acquisition and maintenance of plasmids. Here, we have analyzed and compared the sequences of a large plasmid common to all sequenced Pantoea spp. Results and discussion The Large PantoeaPlasmids (LPP-1) of twenty strains encompassing seven different Pantoea species, including pathogens and endo-/epiphytes of a wide range of plant hosts as well as insect-associated strains, were compared. The LPP-1 plasmid sequences range in size from ~281 to 794 kb and carry between 238 and 750 protein coding sequences (CDS). A core set of 46 proteins, encompassing 2.2% of the total pan-plasmid (2,095 CDS), conserved among all LPP-1 plasmid sequences, includes those required for thiamine and pigment biosynthesis. Phylogenetic analysis reveals that these plasmids have arisen from an ancestral plasmid, which has undergone extensive diversification. Analysis of the proteins encoded on LPP-1 also showed that these plasmids contribute to a wide range of Pantoea phenotypes, including the transport and catabolism of various substrates, inorganic ion assimilation, resistance to antibiotics and heavy metals, colonization and persistence in the host and environment, pathogenesis and antibiosis. Conclusions LPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid. LPP-1 encodes a large array of proteins that have played a major role in the adaptation of the different Pantoea spp. to their various ecological niches and their specialization as pathogens, biocontrol agents or benign saprophytes found in many diverse environments.

Abstract Background The Type VI secretion apparatus is assembled by a conserved set of proteins encoded within a distinct locus. The putative effector proteins Hcp and VgrG are also encoded within these loci. We have identified numerous distinct Type VI secretion system (T6SS) loci in the genomes of several ecologically diverse Pantoea and Erwinia species and detected the presence of putative effector islands associated with the hcp and vgrG genes. Results Between two and four T6SS loci occur among the Pantoea and Erwinia species. While two of the loci (T6SS-1 and T6SS-2) are well conserved among the various strains, the third (T6SS-3) locus is not universally distributed. Additional orthologous loci are present in Pantoea sp. aB-valens and Erwinia billingiae Eb661. Comparative analysis of the T6SS-1 and T6SS-3 loci showed non-conserved islands associated with the vgrG and hcp, and vgrG genes, respectively. These regions had a G+C content far lower than the conserved portions of the loci. Many of the proteins encoded within the hcp and vgrG islands carry conserved domains, which suggests they may serve as effector proteins for the T6SS. A number of the proteins also show homology to the C-terminal extensions of evolved VgrG proteins. Conclusions Extensive diversity was observed in the number and content of the T6SS loci among the Pantoea and Erwinia species. Genomic islands could be observed within some of T6SS loci, which are associated with the hcp and vgrG proteins and carry putative effector domain proteins. We propose new hypotheses concerning a role for these islands in the acquisition of T6SS effectors and the development of novel evolved VgrG and Hcp proteins.

Abstract Background Pediatric acute liver failure (PALF) is an uncommon, devastating illness with significant mortality. Liver transplantation remains the mainstay of treatment for irreversible PALF. The purpose of this study was to determine the etiology and prognostic factors associated with outcome of PALF in South Africa and to evaluate prognostic scoring systems used. Methods Records of 45 pediatric patients younger than 16 years of age who presented with PALF from 1 January 2015 till 31 October 2020 were analysed. Patients were divided into two groups with one group consisting of patients with spontaneous recovery of the liver with supportive treatment (6/45:13.3%) and the second group consisting of patients with poor outcomes who demised (19/45: 42%) or underwent liver transplantation (20/45: 44%). Results The median age of presentation was 3.3 years (IQR 1.8–6.9) with the 1–5 years age group constituting majority of patients (55.6%). Median time to follow up was 6.1 months (IQR 0.2–28.8). Higher liver injury unit scores were observed in patients who had poorer outcomes (P = 0.008) with a threshold of greater than 246 having a sensitivity of 84% and specificity of 83% (P

Background Nutritional screening facilitates the early identification of hospitalised children at risk of malnutrition. Screening tools have scarcely been evaluated in the developing world where the burden of malnutrition is greatest. Methods A retrospective study was undertaken of 113 patients admitted to the general paediatric wards at Rahima Moosa Mother and Child Hospital in Johannesburg, South Africa. Children 6 months to 14 years old were screened for malnutrition using anthropometry and correlating WHO z-scores, and retrospectively assessed for nutritional risk using a modified STAMP (mSTAMP). Results The mSTAMP identified additional patients at nutritional risk. The majority (87%) of children with normal anthropometry scored as medium and high risk using the mSTAMP. Weight loss and length of hospital stay (LOS) were higher in medium and high risk groups: One (5%) low risk child lost weight, compared with 8 (38%) medium and 12 (57%) high risk children (p = 0.021). Low risk children had a median LOS of two and half days (IQR 1–8) compared with medium and high risk groups, with medians of three (IQR 3–8) and six (IQR 4–9) days respectively (p = 0.04). Conclusion The mSTAMP identified more children at risk of malnutrition who may not have been considered for nutritional therapy during the hospital stay using anthropometry screening alone. There is a place for nutritional risk screening in developing world settings, but tools may need to be modified locally. Further studies and validation of these tools in sub-Saharan Africa seem prudent and may result in improved nutrition and outcomes of hospitalised children.

Abstract Most studies investigating the effects of climatological factors on microbial community composition and diversity focus on comparisons of geographically distinct environments (e.g., cold vs hot deserts) or across various temporal scales. Mountain regions provide unique environments to explore relationships between various environmental factors and soil microorganisms given their range of microclimatic conditions and vegetation types. This study investigated micro‐topographically (i.e., north‐/south‐facing slope aspects and flat plateau between them) controlled microbial diversity and community structures across a Lesotho mountain summit. Amplicon sequence analysis revealed that the north‐ and south‐facing slopes were dominated by more Proteobacteria and Bacteroidetes, while the plateau was dominated by more Acidobacteria. Fungi from the phylum Chytridiomycota more strongly dominated the plateau and the north‐facing slope than the south‐facing slope. Slope aspect, through its direct influence on air and soil micro‐climatology and plant diversity, significantly affects bacterial and fungal community structures at this location. These results provide original insight into soil microbial diversity in the Lesotho highlands and offer an opportunity to project the likely response of soil microorganisms to future climate warming in highly variable mountain environments such as the Lesotho highlands.

The human gastrointestinal tract (GIT) is home to an abundance of diverse microorganisms, and the balance of this microbiome plays a vital role in maintaining a healthy GIT. The obstruction of the flow of bile into the duodenum, resulting in obstructive jaundice (OJ), has a major impact on the health of the affected individual. This study sought to identify changes in the duodenal microbiota in South African patients with OJ compared to those without this disorder. Mucosal biopsies were taken from the duodenum of nineteen jaundiced patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and nineteen control participants (non-jaundiced patients) undergoing gastroscopy. DNA extracted from the samples was subjected to 16S rRNA amplicon sequencing using the Ion S5 TM sequencing platform. Diversity metrics and statistical correlation analyses with the clinical data were performed to compare duodenal microbial communities in both groups. Differences in the mean distribution of the microbial communities in the jaundiced and non-jaundiced samples were observed; however, this difference did not reach statistical significance. Of note, there was a statistically significant difference between the mean distributions of bacteria comparing jaundiced patients with cholangitis to those without (p = 0.0026). On further subset analysis, a significant difference was observed between patients with benign (Cholelithiasis) and malignant disease, namely, head of pancreas (HOP) mass (p = 0.01). Beta diversity analyses further revealed a significant difference between patients with stone and non-stone related disease when factoring in the Campylobacter-Like Organisms (CLO) test status (p = 0.048). This study demonstrated a shift in the microbiota in jaundiced patients, especially considering some underlying conditions of the upper GI tract. Future studies should aim to verify these findings in a larger cohort.

Abstract Background The order Enterobacterales encompasses a broad range of metabolically and ecologically versatile bacterial taxa, most of which are motile by means of peritrichous flagella. Flagellar biosynthesis has been linked to a primary flagella locus, flag-1, encompassing ~ 50 genes. A discrete locus, flag-2, encoding a distinct flagellar system, has been observed in a limited number of enterobacterial taxa, but its function remains largely uncharacterized. Results Comparative genomic analyses showed that orthologous flag-2 loci are present in 592/4028 taxa belonging to 5/8 and 31/76 families and genera, respectively, in the order Enterobacterales. Furthermore, the presence of only the outermost flag-2 genes in many taxa suggests that this locus was far more prevalent and has subsequently been lost through gene deletion events. The flag-2 loci range in size from ~ 3.4 to 81.1 kilobases and code for between five and 102 distinct proteins. The discrepancy in size and protein number can be attributed to the presence of cargo gene islands within the loci. Evolutionary analyses revealed a complex evolutionary history for the flag-2 loci, representing ancestral elements in some taxa, while showing evidence of recent horizontal acquisition in other enterobacteria. Conclusions The flag-2 flagellar system is a fairly common, but highly variable feature among members of the Enterobacterales. Given the energetic burden of flagellar biosynthesis and functioning, the prevalence of a second flagellar system suggests it plays important biological roles in the enterobacteria and we postulate on its potential role as locomotory organ or as secretion system.

The thermophilic bacterium Parageobacillus thermoglucosidasius has recently gained interest due to its ability to catalyze the water gas shift reaction, where the oxidation of carbon monoxide (CO) is linked to the evolution of hydrogen (H2) gas. This phenotype is largely predictable based on the presence of a genomic region coding for a carbon monoxide dehydrogenase (CODH—Coo) and hydrogen evolving hydrogenase (Phc). In this work, seven previously uncharacterized strains were cultivated under 50% CO and 50% air atmosphere. Despite the presence of the coo—phc genes in all seven strains, only one strain, Kp1013, oxidizes CO and yields H2. The genomes of the H2 producing strains contain unique genomic regions that code for proteins involved in nickel transport and the detoxification of catechol, a by-product of a siderophore-mediated iron acquisition system. Combined, the presence of these genomic regions could potentially drive biological water gas shift (WGS) reaction in P. thermoglucosidasius.

Abstract Hydrogen gas represents a promising alternative energy source to dwindling fossil fuel reserves, as it carries the highest energy per unit mass and its combustion results in the release of water vapour as only byproduct. The facultatively anaerobic thermophile Parageobacillus thermoglucosidasius is able to produce hydrogen via the water–gas shift reaction catalyzed by a carbon monoxide dehydrogenase–hydrogenase enzyme complex. Here we have evaluated the effects of several operating parameters on hydrogen production, including different growth temperatures, pre-culture ages and inoculum sizes, as well as different pHs and concentrations of nickel and iron in the fermentation medium. All of the tested parameters were observed to have a substantive effect on both hydrogen yield and (specific) production rates. A final experiment incorporating the best scenario for each tested parameter showed a marked increase in the H2 production rate compared to each individual parameter. The optimised parameters serve as a strong basis for improved hydrogen production with a view of commercialisation of this process.

Background: The Health Professions Council of South Africa (HPCSA) issued early hearing detection and intervention guidelines, which has universal newborn hearing screening (UNHS) as one of the important goals. Despite established evidence of the importance of UNHS globally, there has been no mandated formalised and standardised implementation as yet in South Africa. Objectives: The aim of this study was to describe the outcomes of newborn hearing screening (NHS) in an academic secondary level hospital in Johannesburg, South Africa. Methods: This was a prospective non-experimental feasibility study over a 3-month period, involving conducting hearing screening of 121 neonates. Audiologists conducted a risk factor assessment, otoscopic examinations and distortion product otoacoustic emissions (DPOAEs) screening on each neonate, with follow-up appointments for re-screening and diagnostic audiological assessments for all neonates with refer findings. Data were analysed using STATA intercooled version 11©, through both descriptive and inferential statistics (Fisher’s exact test), with significance established where p-values less than 0.05 were considered statistically significant. Results: Of the 121 neonates screened, the majority (75%) were screened in the first 24 h of life. A high refer rate (47%) of the total sample was found on DPOAE screening. No maternal or neonatal risk factors were found to be significantly associated with refer findings. Conclusion: Findings contribute towards the existing evidence base that raises implications for successful implementation of NHS programmes in public healthcare in South Africa. Screening protocols need to consider the timing of screening, the measures and procedures adopted in the screening protocols, as well as the follow-up strategies.

Parageobacillus thermoglucosidasius is known to catalyse the biological water gas shift (WGS) reaction, a pathway that serves as a source of alternative energy and carbon to a wide variety of bacteria. Despite increasing interest in this bacterium due to its ability to produce biological hydrogen through carbon monoxide (CO) oxidation, there are no data on the effect of toxic CO gas on its physiology. Due to its general requirement of O2, the organism is often grown aerobically to generate biomass. Here, we show that carbon monoxide (CO) induces metabolic changes linked to distortion of redox balance, evidenced by increased accumulation of organic acids such as acetate and lactate. This suggests that P. thermoglucosidasius survives by expressing several alternative pathways, including conversion of pyruvate to lactate, which balances reducing equivalents (oxidation of NADH to NAD+), and acetyl-CoA to acetate, which directly generates energy, while CO is binding terminal oxidases. The data also revealed clearly that P. thermoglucosidasius gained energy and grew during the WGS reaction. Combined, the data provide critical information essential for further development of the biotechnological potential of P. thermoglucosidasius.

Welwitschia mirabilis is an ancient and rare plant distributed along the western coast of Namibia and Angola. Several aspects of Welwitschia biology and ecology have been investigated, but very little is known about the microbial communities associated with this plant. This study reports on the bacterial and fungal communities inhabiting the rhizosphere of W. mirabilis and the surrounding bulk soil. Rhizosphere communities were dominated by sequences of Alphaproteobacteria and Euromycetes, while Actinobacteria, Alphaproteobacteria, and fungi of the class Dothideomycetes jointly dominated bulk soil communities. Although microbial communities within the rhizosphere and soil samples were highly variable, very few "species" (OTUs defined at a 97% identity cut-off) were shared between these two environments. There was a small 'core' rhizosphere bacterial community (formed by Nitratireductor, Steroidobacter, Pseudonocardia and three Phylobacteriaceae) that together with Rhizophagus, an arbuscular mycorrhizal fungus, and other putative plant growth-promoting microbes may interact synergistically to promote Welwitschia growth.

Nutritional screening facilitates the early identification of hospitalised children at risk of malnutrition. Screening tools have scarcely been evaluated in the developing world where the burden of malnutrition is greatest. A retrospective study was undertaken of 113 patients admitted to the general paediatric wards at Rahima Moosa Mother and Child Hospital in Johannesburg, South Africa. Children 6 months to 14 years old were screened for malnutrition using anthropometry and correlating WHO z-scores, and retrospectively assessed for nutritional risk using a modified STAMP (mSTAMP). The mSTAMP identified additional patients at nutritional risk. The majority (87%) of children with normal anthropometry scored as medium and high risk using the mSTAMP. Weight loss and length of hospital stay (LOS) were higher in medium and high risk groups: One (5%) low risk child lost weight, compared with 8 (38%) medium and 12 (57%) high risk children (p = 0.021). Low risk children had a median LOS of two and half days (IQR 1–8) compared with medium and high risk groups, with medians of three (IQR 3–8) and six (IQR 4–9) days respectively (p = 0.04). The mSTAMP identified more children at risk of malnutrition who may not have been considered for nutritional therapy during the hospital stay using anthropometry screening alone. There is a place for nutritional risk screening in developing world settings, but tools may need to be modified locally. Further studies and validation of these tools in sub-Saharan Africa seem prudent and may result in improved nutrition and outcomes of hospitalised children. [ABSTRACT FROM AUTHOR]

Geobacillus is a genus of Gram-positive, aerobic, spore-forming obligate thermophiles. The descriptions and subsequent affiliations of the species in the genus have mostly been based on polyphasic taxonomy rules that include traditional sequence-based methods such as DNA–DNA hybridization and comparison of 16S rRNA gene sequences. Currently, there are fifteen validly described species within the genus. The availability of whole genome sequences has provided an opportunity to validate and/or re-assess these conventional estimates of genome relatedness. We have applied whole genome approaches to estimate the phylogenetic relatedness among the sixty-three Geobacillus strains for which genome sequences are currently publicly available, including the type strains of eleven validly described species. The phylogenomic metrics AAI (Average Amino acid Identity), ANI (Average Nucleotide Identity) and dDDH (digital DNA–DNA hybridization) indicated that the current genus Geobacillus is comprised of sixteen distinct genomospecies, including several potentially novel species. Furthermore, a phylogeny constructed on the basis of the core genes identified from the whole genome analyses indicated that the genus clusters into two monophyletic clades that clearly differ in terms of nucleotide base composition. The G + C content ranges for clade I and II were 48.8–53.1% and 42.1–44.4%, respectively. We therefore suggest that the Geobacillus species currently residing within clade II be considered as a new genus. [ABSTRACT FROM AUTHOR]