Prevalence and Antimicrobial Resistance of Paeniclostridium sordellii in Hospital Settings

(1) Background: The purpose of this study was to determine the prevalence of clostridia strains in a hospital environment in Algeria and to evaluate their antimicrobial susceptibility to antibiotics and biocides. (2) Methods: Five hundred surface samples were collected from surfaces in the intensive care unit and surgical wards in the University Hospital of Tlemcen, Algeria. Bacterial identification was carried out using MALDI-TOF-MS, and then the minimum inhibitory concentrations (MICs) of various antimicrobial agents were determined by the E-test method. P. sordellii toxins were searched by enzymatic and PCR assays. Seven products intended for daily disinfection in the hospitals were tested against Clostridium spp. spore collections. (3) Results: Among 100 isolates, 90 P. sordellii were identified, and all strains were devoid of lethal and hemorrhagic toxin genes. Beta-lactam, linezolid, vancomycin, tigecycline, rifampicin, and chloramphenicol all proved effective against isolated strains. Among all strains tested, the spores of P. sordellii exhibited remarkable resistance to the tested biocides compared to other Clostridium species. The (chlorine-based 0.6%, 30 min), (glutaraldehyde solution 2.5%, 30 min), and (hydrogen peroxide/peracetic acid 3%, 15 min) products achieved the required reduction in spores. (4) Conclusions: Our hospital’s current cleaning and disinfection methods need to be optimized to effectively remove spores from caregivers’ hands, equipment, and surfaces.

Microbial production of 2,3-butanediol from rice husk using anaerobic Clostridium species

Interest in the area of biomass based-product production is increasing all over the world due to the environmental challenges posed by fossil fuel and fear of its extinction. Production of biofuel and other compounds especially from agricultural waste can reduce these environmental problems because of its sustainability and environmentally friendliness. One of the major petrochemical product widely used in many industries is 2,3-butanediol and was found to be produced from agricultural wastes by microorganisms. Therefore, Microbial production of 2,3-butanediol from rice husk using Clostridium species was investigated in this research. Structural composition of the rice husk was determined before and after pretreatment. Hemicellulose and lignin content of rice husk was determined after extraction while cellulose was determined as the difference from the extractives, hemicelluloses and lignin. Dilute (2%) NaOH was used for the pretreatment of rice husk. Hydrolysis was carried out using Aspergillus niger and reducing sugar released was determined using standard method with UV-VIS spectrophotometer. Clostridium species was isolated from sugarcane bagasse, identified using basic morphological and molecular biology techniques. The fermentation of rice husk was performed using the Clostridium species. Fermentation by-product was determined using Gas Chromatography Mass-spectrometry. Cellulose content increased from 32% before pretreatment to 53.3% after pretreatment, lignin increased from 8.4% before pretreatment to 30.7% after pretreatmemt and hemicellulose decreased from 30% before pretreatment to 8% after pretreatment. A total of 1.05 g/l of reducing sugar was released after enzymatic hydrolysis of the rice husk with Aspergillus niger. Alcohol 2,3-butanediol (0.6%) and Furfuryl alcohol (0.45%) were detected in the by-product of fermentation. Other compounds detected are fatty acids that ranges from C16 to C25 with 9,12-Octadecanoic acid as the major fatty acid. From the results of this work, Rice husk was found to have substantial amount of sugar (cellulose and hemicelluce) that can be converted to valuable product including 2,3-butanediol. Keywords: Biofuel, Bio-refinary, Cellulose, Clostrudium, fermentation.

The morphogenetic protein CotE drives exosporium formation by positioning CotY and ExsY during sporulation of Bacillus cereus

The exosporium is the outermost spore layer of some Bacillus and Clostridium species and related organisms. It mediates interactions of spores with their environment, modulates spore adhesion and germination and could be implicated in pathogenesis. The exosporium is composed of a crystalline basal layer, formed mainly by the two cysteine-rich proteins CotY and ExsY, and surrounded by a glycoprotein hairy nap. The morphogenetic protein CotE is necessary for Bacillus cereus exosporium integrity, but how CotE directs exosporium assembly remains unknown. Here, we followed the localization of SNAP-tagged CotE, -CotY and -ExsY during B. cereus sporulation, using super-resolution fluorescence microscopy and evidenced interactions among these proteins. CotE, CotY and ExsY are present as complexes at all sporulation stages and follow a similar localization pattern during endospore formation that is reminiscent of the localization of Bacillus subtilis CotE. We show that B. cereus CotE drives the formation of one cap at both forespore poles by positioning CotY and then guides forespore encasement by ExsY, thereby promoting exosporium elongation. By these two actions, CotE ensures the formation of a complete exosporium. Importantly, we demonstrate that the assembly of the exosporium is not a unidirectional process as previously proposed but it is performed through the formation of two caps, as observed during B. subtilis coat morphogenesis. It appears that a general principle governs the assembly of the spore surface layers of Bacillaceae.

Dynamics of Dark Fermentation Microbial Communities in the Light of Lactate and Butyrate Production

Background: This study focuses on the processes occurring during acidogenic step of anaerobic digestion, especially resulting from nutritional interactions between dark fermentation (DF) bacteria and lactic acid bacteria (LAB). Previously, we have confirmed that DF microbial communities fed on molasses are able to convert lactate and acetate to butyrate in batch experiments. The aims of the study were: (i) to recognize biodiversity of DF microbial communities able and unable to convert lactate and acetate to butyrate and (ii) to define the conditions for the transformation in static batch experiments.Results: Sucrose stimulated bacterial growth, especially LAB. In the samples where the microbial communities fermented media containing carbohydrates the two main tendencies were observed: (i) a low pH (pH≤4), lactate and ethanol as the main fermentation products, microbial communities dominated with Lactobacillus, Bifidobacterium, Leuconostoc and Fructobacillus was characterised by a low biodiversity; (ii) pH in the range 5.0-6.0, butyrate dominated among the fermentation products, the microbial communities composed mailny of Clostridium (especially Clostridium sensu stricto 12), Lactobacillus, Bifidobacterium and Prevotella. The biodiversity increased with the ability to convert acetate and lactate to butyrate. The microbial communities processing exclusively lactate and acetate showed the highest biodiversity and was dominated by Clostridium (especially Clostridium sensu stricto 12). LAB were reduced, other genera such as Terrisporobacter, Lachnoclostridium, Paraclostridium or Sutterella were found. Butyrate was the main metabolite and pH was 7. WGS analysis of the selected butyrate-producing microbial communities independently on the substrate, revealed C. tyrobutyricum as a dominant Clostridium species. Conclusions: The batch tests revealed dynamics of metabolic activity and composition of DF microbial communities dependent on fermentation conditions. The results expand our knowledge on lactate to butyrate conversion by DF microbial communities. The relevant factor for conversion of lactate and acetate to butyrate in the presence of carbohydrates is pH in the range 5-6 and the balance between LAB (especially Lactobacillus), lactate and acetate producers (Bifidobacterium) and butyrate producers (mainly Clostridium) as well Prevotella. The pH below 4 and ethanol concentration might be the signalling factors responsible for metabolic shift of the dark fermentation microbial communities towards lactate fermentation.