Bacillus cereus-Attributable Primary Cutaneous Anthrax-Like Infection in Newborn Infants, India

Bacillus cereus

Bacillus cereus is an emerging food-borne pathogen responsible for two types of food poisoning: emetic and diarrhoeal type. Here we report an emetic type of food-borne illness attributable to Bacillus cereus. On 2nd February, 2021, 202 people suffered from pain in abdomen and vomiting after consuming the rice provided during a public gathering in Diphu, Assam. Culture of leftover fried rice showed growth of Bacillus cereus group of organisms. Molecular detection of enterotoxin and emetic toxin genes was done in the isolated strains by polymerase chain reaction. Multi locus sequence typing (MLST) and phylogenetic analysis was done to characterise the isolated strains. A total of five strains of Bacillus cereus were isolated. Ces gene was found in isolates GMC22 & GMC24 and other enterotoxins producing genes were found in isolates GMC23 and GMC24. MLST identified four sequence types (STs) (ST1051, ST1616, ST998 and ST1000). Phylogenetic analysis clustered ST-1051 assigned to the GMC22 strain into the previously defined clade I and was in close relation with ST-144, representing a new cereulide-producing emetic cluster. As Bacillus cereus is a common contaminant of foods, it is essential to evaluate the pathogenic potential of the bacteria for a definite link between causative agents and the illness. MLST can be used to characterize the Bacillus cereus strains isolated from outbreak samples in order to link the probable pathogens with the illness. In this outbreak, we suggest that ST-1051 is the strain responsible for the food-borne illness, which was predominantly of emetic type.

Late-onset sepsis in newborns caused by Bacillus Cereus: a case report and literature review

Bacillus cereus is a bacterium capable of causing late-onset neonatal sepsis. By analyzing 11 cases, this study investigates the diagnosis, treatment, and prognosis of Bacillus cereus infections, aiming to provide insights into clinical diagnosis and therapy. The study scrutinized 11 instances of late-onset neonatal sepsis, including two fatalities attributable to Bacillus cereus, one accompanied by cerebral hemorrhage. An examination and analysis of these cases' symptoms, signs, laboratory tests, and treatment processes, along with a review of related literature from 2010 to 2020, revealed a high mortality rate of 41.38% in non-gastrointestinal infections caused by Bacillus cereus. Our findings underscore the critical importance of rapid diagnosis and effective antimicrobial therapy in reducing mortality rates. Once the source of infection is identified, implementing effective infection control measures is essential.

Pathogenic Bacilli as an Emerging Biothreat?

Bacillus anthracis, present as a very durable endospore in soil, causes zoonotic illness which is mainly associated with herbivores and domestic animals. Human cases are scarce and often involve populations close to infected livestock. If anthrax is no longer of public health concern in developed countries, B. anthracis is one of the top-tier biological weapon agents. It is classified by the CDC as a category A agent. Since 1994, emerging strains of Bacillus cereus have been associated with anthrax-like disease in mammals. Some clinical strains of B. cereus harbor anthrax-like plasmid genes (pXO1 and pXO2) associated with non-human primate and human infections, with the same clinical presentation of inhalation anthrax and mortality rates. Although currently restricted to certain limited areas of circulation, the emergence of these new strains of B. cereus extends the list of potential agents possibly usable for bioterrorism or as a biological weapon. It is therefore important to improve our knowledge of the phylogeny within the B. cereus sensu lato group to better understand the origin of these strains. We can then more efficiently monitor the emergence of new strains to better control the risk of infection and limit potentially malicious uses.

Strains Associated with Two 2020 Welder Anthrax Cases in the United States Belong to Separate Lineages within Bacillus cereus sensu lato

Anthrax-causing members of Bacillus cereus sensu lato (s.l.) pose a serious threat to public health. While most anthrax-causing strains resemble B. anthracis phenotypically, rare cases of anthrax-like illness caused by strains resembling “B. cereus” have been reported. Here, whole-genome sequencing was used to characterize three B. cereus s.l. isolates associated with two 2020 welder anthrax cases in the United States, which resembled “B. cereus” phenotypically. Comparison of the three genomes sequenced here to all publicly available, high-quality B. cereus s.l. genomes (n = 2890 total genomes) demonstrated that genomes associated with each case effectively belonged to separate species at the conventional 95% average nucleotide identity prokaryotic species threshold. Two PubMLST sequence type 78 (ST78) genomes affiliated with a case in Louisiana were most closely related to B. tropicus and possessed genes encoding the Bps exopolysaccharide capsule, as well as hemolysin BL (Hbl) and cytotoxin K (CytK). Comparatively, a ST108 genome associated with a case in Texas was most closely related to B. anthracis; however, like other anthrax-causing strains most closely related to B. anthracis, this genome did not possess Bps-, Hbl-, or CytK-encoding genes. Overall, results presented here provide insights into the evolution of anthrax-causing B. cereus s.l.

Rapid Identification of Bacillus anthracis In Silico and On-Site Using Novel Single-Nucleotide Polymorphisms

Bacillus anthracis is a spore-forming bacterium that causes life-threatening infections in animals and humans and has been used as a bioterror agent. Rapid and reliable detection and identification of B. anthracis are of primary interest for both medical and biological threat-surveillance purposes. Few chromosomal sequences provide enough polymorphisms to clearly distinguish B. anthracis from closely related species. We analyzed 18 loci of the chromosome of B. anthracis and discovered eight novel single-nucleotide polymorphism (SNP) sites that can be used for the specific identification of B. anthracis. Using these SNP sites, we developed software-named AGILE V1.1 (anthracis genome-based identification with high-fidelity E-probe)-for easy, user-friendly identification of B. anthracis from whole-genome sequences. We also developed a recombinase polymerase amplification-Cas12a-based method that uses nucleic acid extracts for the specific, rapid, in-the-field identification of B. anthracis based on these SNPs. Via this method and B. anthracis-specific CRISPR RNAs for the target CR5_2, CR5_1, and Ba813 SNPs, we clearly detected 5 aM genomic DNA. This study provides two simple and reliable methods suitable for use in local hospitals and public health programs for the detection of B. anthracis. IMPORTANCE Bacillus anthracis is the etiologic agent of anthrax, a fatal disease and a potential biothreat. A specific, accurate, and rapid method is urgently required for the identification of B. anthracis. We demonstrate the potential of using eight novel SNPs for the rapid and accurate detection of B. anthracis via in silico and laboratory-based testing methods. Our findings have important implications for public health responses to disease outbreaks and bioterrorism threats.

Bacillus cereus Invasive Infections in Preterm Neonates: an Up-to-Date Review of the Literature

Bacillus cereus group species are widespread, Gram-positive, spore-forming environmental bacteria. B. cereus sensu stricto is one of the major causes of food poisoning worldwide. In high-risk individuals, such as preterm neonates, B. cereus infections can cause fatal infections. It is important to note that the phenotypic identification methods commonly used in clinical microbiology laboratories make no distinction between B. cereus sensu stricto and the other members of the group (Bacillus anthracis excluded). As a result, all the invasive infections attributed to B. cereus are not necessarily due to B. cereus sensu stricto but likely to other closely related species of the B. cereus group. Next-generation sequencing (NGS) should be used to characterize the whole genome of the strains belonging to the B. cereus group. This could confirm whether the strains involved in previously reported B. cereus invasive infections preferentially belong to formerly known or emerging individual species. Moreover, infections related to B. cereus group species have probably been overlooked, since their isolation in human bacteriological samples has for a long time been regarded as an environmental contaminant of the cultures. Recent studies have questioned the emergence or reemergence of B. cereus invasive infections in preterm infants. This review reports our current understanding of B. cereus infections in neonates, including taxonomical updates, microbiological characteristics, bacterial identification, clinical features, host-pathogen interactions, environmental sources of contamination, and antimicrobial resistance.

Comparative analysis of Bacillus cereus group isolates' resistance using disk diffusion and broth microdilution and the correlation between antimicrobial resistance phenotypes and genotypes

Bacillus cereus group isolates (n = 85) were screened for phenotypic resistance to 18 antibiotics using broth microdilution and CLSI M45 Bacillus spp. breakpoints. The susceptibility to 9 out of 18 antibiotics was tested also using disk diffusion method and M100 Staphylococcus spp. breakpoints. Overall, a high prevalence of susceptibility to clinically relevant antibiotics was identified using broth microdilution. For most tested antibiotics, a poor correlation was found between zones of inhibition and minimum inhibitory concentrations. Using the broth microdilution results as a reference for comparison, we identified high error rates and low categorical agreement between results produced using disk diffusion and broth microdilution for the seven tested antibiotics with defined breakpoints. This suggests that disk diffusion should be avoided for AST of B. cereus group isolates. Further, we detected antimicrobial resistance genes with ARIBA and ABRIcate to calculate the sensitivity and specificity for predicting phenotypic resistance determined using broth microdilution based on the presence of detected antimicrobial resistance genes (ARGs). ARGs with poor sensitivity and high specificity included rph (rifampicin, 0%, 93%), mph (erythromycin, 0%, 99%), bla1 (penicillin, 29%, 100), and blaZ (penicillin, 56%, 100%). Compared to penicillin, bla1 and blaZ had lower specificity for the prediction of ampicillin resistance. Overall, none of the ARGs had both high sensitivity and specificity, suggesting the need for further study of the mechanisms underlying phenotypic antimicrobial resistance in the B. cereus group. IMPORTANCE Bacillus cereus group includes human pathogens that can cause severe infections requiring antibiotic treatment. Screening of environmental and food isolates for antimicrobial resistance can provide insight into what antibiotics may be more effective therapeutic options based on the lower prevalence of resistance. Currently, the comparison of antimicrobial susceptibility testing results using the disk diffusion method is complicated by the fact that many previous studies have used Staphylococcus spp. breakpoints to interpret their results. In this study, we compared the results of disk diffusion interpreted using the Staphylococcus spp. breakpoints against the results of broth microdilution interpreted using Bacillus spp. breakpoints. We demonstrated that the disk diffusion method does not produce reliable results for B. cereus group isolates and should therefore be avoided. This study also provides new insight into poor associations between the presence of antimicrobial resistance genes and resistance phenotypes for the B. cereus group.

C-protein α-antigen modulates the lantibiotic thusin resistance in Streptococcus agalactiae

Screening for producers of potent antimicrobial peptides, resulted in the isolation of Bacillus cereus BGNM1 with strong antimicrobial activity against Listeria monocytogenes. Genome sequence analysis revealed that BGNM1 contains the gene cluster associated with the production of the lantibiotic, thusin, previously identified in B. thuringiensis. Purification of the antimicrobial activity confirmed that strain BGMN1 produces thusin. Both thusin sensitive and resistant strains were detected among clinical isolates of Streptococcus agalactiae. Random mutagenesis of a thusin sensitive strain, S. agalactiae B782, was performed in an attempt to identify the receptor protein for thusin. Three independent thusin resistant mutants were selected and their complete genomes sequenced. Comparative sequence analysis of these mutants with the WT strain revealed that duplication of a region encoding a 79 amino acids repeat in a C-protein α-antigen was a common difference, suggesting it to be responsible for increased resistance to thusin. Since induced thusin resistant mutants showed higher level of resistance than the naturally resistant B761 strain, complete genome sequencing of strain B761 was performed to check the integrity of the C-protein α-antigen-encoding gene. This analysis revealed that this gene is deleted in B761, providing further evidence that this protein promotes interaction of the thusin with receptor.

Keeping up with the Bacillus cereus group: taxonomy through the genomics era and beyond

The Bacillus cereus group, also known as B. cereus sensu lato (s.l.), is a species complex that contains numerous closely related lineages, which vary in their ability to cause illness in humans and animals. The classification of B. cereus s.l. isolates into species-level taxonomic units is thus essential for informing public health and food safety efforts. However, taxonomic classification of these organisms is challenging. Numerous-often conflicting-taxonomic changes to the group have been proposed over the past two decades, making it difficult to remain up to date. In this review, we discuss the major nomenclatural changes that have accumulated in the B. cereus s.l. taxonomic space prior to 2020, particularly in the genomic sequencing era, and outline the resulting problems. We discuss several contemporary taxonomic frameworks as applied to B. cereus s.l., including (i) phenotypic, (ii) genomic, and (iii) hybrid nomenclatural frameworks, and we discuss the advantages and disadvantages of each. We offer suggestions as to how readers can avoid B. cereus s.l. taxonomic ambiguities, regardless of the nomenclatural framework(s) they choose to employ. Finally, we discuss future directions and open problems in the B. cereus s.l. taxonomic realm, including those that cannot be solved by genomic approaches alone.

Fulminant Necrotizing Soft-tissue Infection in an Extremely Low Gestational Age Infant

We report a case of rapidly progressive necrotizing skin and soft-tissue infection caused by Bacillus cereus in an extremely low for gestational age infant. This case reminds clinicians to consider this opportunistic pathogen as the etiologic agent in fulminant necrotizing infections in vulnerable hosts, and to institute appropriate therapy in a timely fashion.

Identification of Chemical Profiles and Biological Properties of Rhizophora racemosa G. Mey. Extracts Obtained by Different Methods and Solvents

Mangrove forests exemplify a multifaceted ecosystem since they do not only play a crucial ecological role but also possess medicinal properties. Methanolic, ethyl acetate and aqueous leaf and bark extracts were prepared using homogenizer-assisted extraction (HAE), infusion and maceration (with and without stirring). The different extracts were screened for phytochemical profiling and antioxidant capacities in terms of radical scavenging (DPPH, ABTS), reducing potential (CUPRAC, FRAP), total antioxidant capacity and chelating power. Additionally, R. racemosa was evaluated for its anti-diabetic (α-amylase, α-glucosidase), anti-tyrosinase and anti-cholinesterase (AChE, BChE) activities. Additionally, antimycotic and antibacterial effects were investigated against Eescherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Listeria monocytogenes, Enterobacter cloacae, Bacillus cereus, Micrococcus luteus, Staphylococcus aureus, Aspergillus fumigatus, Aspergillus niger, Trichoderma viride, Penicillium funiculosum, Penicillium ochrochloron and Penicillium verrucosum. Finally, based on phytochemical fingerprint, in silico studies, including bioinformatics, network pharmacology and docking approaches were conducted to predict the putative targets, namely tyrosinase, lanosterol-14-α-demethylase and E. coli DNA gyrase, underlying the observed bio-pharmacological and microbiological effects. The methanolic leave and bark extracts (prepared by both HAE and maceration) abounded with phenolics, flavonoids, phenolic acids and flavonols. Results displayed that both methanolic leaf and bark extracts (prepared by HAE) exhibited the highest radical scavenging, reducing potential and total antioxidant capacity. Furthermore, our findings showed that the highest enzymatic inhibitory activity recorded was with the tyrosinase enzyme. In this context, bioinformatics analysis predicted putative interactions between tyrosinase and multiple secondary metabolites including apigenin, luteolin, vitexin, isovitexin, procyanidin B, quercetin and methoxy-trihydroxyflavone. The same compounds were also docked against lanosterol-14α-demethylase and E. Coli DNA gyrase, yielding affinities in the submicromolar–micromolar range that further support the observed anti-microbial effects exerted by the extracts. In conclusion, extracts of R. racemosa may be considered as novel sources of phytoanti-oxidants and enzyme inhibitors that can be exploited as future first-line pharmacophores.