Molecular characterization of an outbreak-involved Bacillus anthracis strain confirms the spillover of anthrax from West Africa

Background Anthrax,a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis,remains a major global public health concern,especially in countries with limited resources.Sierra Leone,a West African country historically plagued by anthrax,has almost been out of report on this disease in recent decades.In this study,we described a large-scale anthrax outbreak affecting both animals and humans and attempted to characterize the path-ogenusingmoleculartechniques.Methods The causative agent of the animal outbreak in Port Loko District,Sierra Leone,between March and May 2022 was identified using the nanopore sequencing technique.A nationwide active surveillance was implemented from May 2022 to June 2023 to monitor the occurrence of anthrax-specific symptoms in humans.Suspected cases were subsequently verified using quantitative polymerase chain reaction.Full-genome sequencing was accomplished by combining long-read and short-read sequencing methods.Subsequent phylogenetic analysis was performed based on the full-chromosome single nucleotide polymorphisms.Results The outbreak in Port Loko District,Sierra Leone,led to the death of 233 animals between March 26th and May 16th,2022.We ruled out the initial suspicion of Anaplasma species and successfully identified B.anthracis as the causative agent of the outbreak.As a result of the government's prompt response,out of the 49 suspected human cases identifed during the one-year active surveillance,only 6 human cases tested positive,all within the frst month after the official declaration of the outbreak.The phylogenetic analysis indicated that the BaSL2022 isolate responsible for the outbreak was positioned in the A.Br.153 clade within the TransEuroAsian group of B.anthracis.Conclusions We successfully identifed a large-scale anthrax outbreak in Sierra Leone.The causative isolate of B.anthracis,BaSL2022,phylogenetically bridged other lineages in A.Br.153 clade and neighboring genetic groups,A.Br.144 and A.Br.148,eventually confirming the spillover of anthrax from West Africa.Given the wide dissemination of B.anthracis spores,it is highly advisable to effectively monitor the potential reoccurrence of anthrax outbreaks and to launch campaigns to improve public awareness regarding anthrax in Sierra Leone.

Inhibitory effects of nisin-coated multi-walled carbon nanotube sheet on biofilm formation from Bacillus anthracis spores

Multi-walled carbon nanotube（MWCNT） sheet was fabricated from a drawable MWCNT forest and then deposited on poly（methyl methacrylate） film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.

Proteomics Reveals that Proteins Expressed During the Early Stage of Bacillus anthracis Infection Are Potential Targets for the Development of Vaccines and Drugs

In this review, we advance a new concept in developing vaccines and/or drugs to target speci?c proteins expressed during the early stage of Bacillus anthracis (an- thrax) infection and address existing challenges to this concept. Three proteins (immune inhibitor A, GPR-like spore protease, and alanine racemase) initially identi?ed by proteomics in our laboratory were found to have di?erential expres- sions during anthrax spore germination and early outgrowth. Other studies of di?erent bacillus strains indicate that these three proteins are involved in either germination or cytotoxicity of spores, suggesting that they may serve as potential targets for the design of anti-anthrax vaccines and drugs.

一种荧光碳点R-CDs对炭疽芽孢杆菌标志物的响应检测

采用简单的水解法制备荧光探针R-CDs,高灵敏、可视化地现场检测炭疽芽孢杆菌(Bacillus anthracis)孢子标志物,探索一种荧光碳点R-CDs对炭疽芽孢杆菌标志物的响应检测方法。结果显示,该方法可以保持较好的线性关系,线性相关系数r为0.995 4和0.994 9;利用3σ/k计算方法的检出限(LOD)为48.40 nmol/L。建立了一套操作简便、切实可行的炭疽快速检测技术,能够及时发现问题,有效提高国家进出口制品安全质量,保障人民身体健康,同时具有功能多样化、高效化、应用广泛化等优点,该技术成果转化性强,应用价值和利润值较高,市场推广前景广阔。

Gastrointestinal Anthrax:A Case and Review of Literature

Anthrax which is caused by Bacillus anthracis is typically a disease of herbivores. Spores existing in the skin, meat, hair or mouth and nose of animals are transmitted to humans through contact with a break in the skin, consumption of infected meat or inhalation of spores [1]. Infected uncooked or insufficiently cooked meats cause oropharyngeal and gastrointestinal system (GIS) anthrax. When this infected materials swallowed anthrax spores may cause lesions from the oral cavity to the caecum. The diagnosis of gastrointestinal system (GIS) anthrax is difficult due to insidious clinical progression of the disease and difficulty in the isolation of agent pathogen. Releated symptoms of GIS anthrax are sore throat, neck swelling, diffuculty swallowing, stomach pain, anoreksia, bloody diarrhea, nause, bloody vomiting and fever. Supportive and antibiotic treatments are required. Benzylpenicillin, rifampicin, clindamycin, chloramphenicol, imipenem/cilastatin, or vancomycin can be use for treatment, ciprofloxacin or doxycycline may be added to this treat- ment for serious cases. To emphasize the necessity of taking precautions, an oropharyngeal and intestinal anthrax case due to consumption of infected and insufficiently cooked meat is presented below.

Tb^(3+)-xylenol orange complex-based colorimetric and luminometric dual-readout sensing platform for dipicolinic acid and metal ions

A dual-readout sensing platform based on two signal transduction channels can integrate the unique advantages of each sensing pattern,compensate for the deficiency in the adaptive capacity,and enable a more convincing performance in analytical applications.Here,we introduce a responsive molecule dye,xylenol orange(XO),to combine with lanthanide terbium ions(Tb^(3+)).The resultant Tb^(3+)-XO complex exhibited tunable optical properties and was used as a novel colorimetric and luminometric dual-readout sensing platform for assaying the anthrax biomarker,dipicolinic acid(DPA).In the presence of Tb^(3+),the XO solution underwent a color change from yellow to magenta;however,upon adding DPA,the color changed back to yellow immediately,accompanied by the characteristic luminescence emission of Tb^(3+).Considering the strong affinity between DPA/XO and metal ions,the proposed sensing platform was further employed for the determination and differentiation of certain metal ions using linear discriminant analysis.This convenient dual-readout sensing platform offers several notable features and significantly promotes the application and development of lanthanide-based materials.

Genetic source tracking of an anthrax outbreak in Shaanxi province,China

Background:Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis.From 26 July to 8 August 2015,an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganquan County,Shaanxi province in China.The genetic source tracking analysis of the anthrax outbreak was performed by molecular epidemiological methods in this study.Methods:Three molecular typing methods,namely canonical single nucleotide polymorphisms(canSNP),multiple-locus variable-number tandem repeat analysis(MLVA),and single nucleotide repeat(SNR)analysis,were used to investigate the possible source of transmission and identify the genetic relationship among the strains isolated from human cases and diseased animals during the outbreak.Results:Five strains isolated from diseased mules were clustered together with patients’isolates using canSNP typing and MLVA.The causative B.anthracis lineages in this outbreak belonged to the A.Br.001/002 canSNP subgroup and the MLVA15-31 genotype(the 31 genotype in MLVA15 scheme).Because nine isolates from another four provinces in China were clustered together with outbreak-related strains by the canSNP(A.Br.001/002 subgroup)and MLVA15 method(MLVA15-31 genotype),still another SNR analysis(CL10,CL12,CL33,and CL35)was used to source track the outbreak,and the results suggesting that these patients in the anthrax outbreak were probably infected by the same pathogen clone.Conclusions:It was deduced that the anthrax outbreak occurred in Shaanxi province,China in 2015 was a local occurrence.