According to the World Health Organization, foodborne diseases are a major public health problem, particularly in developing countries including the Republic of Congo. They are responsible for several episodes of diar...According to the World Health Organization, foodborne diseases are a major public health problem, particularly in developing countries including the Republic of Congo. They are responsible for several episodes of diarrhea, especially in children under five years old. There is no reliable epidemiological data on the pathogenicity of the Shigella spp. strains circulating in the whole Republic of Congo drafting this paper. The purpose of this study was to examine the Shigella spp strain pathogenicity close to an environment contaminated with faeces in the city of Brazzaville. As a result, 54 isolates have been associated with Shigella spp. The gastric acid resistance test performed on Shigella Environmental Strain (SES) and Shigella Clinical Strains (SCS) resulted in 38.8% (21/54) and 100% acid resistant, respectively. Shigella spp. Strains (SES and SCS) were ranged in a survival percentage from 11% to 93%. By monitoring Biosurfactant-Like Molecule (BLM) production, we showed that the BLM production of SES and SCS was highly dependent on bacterial culture density involving the Quorum Sensing (QS). S. flexneri, S. boydii, and S. sonnei and as well as SES and SCS were able to invade and contaminate eggs by colonizing egg yolk. The counting bacteria were ranging from two to 5 × 10<sup>7</sup> CFU/mL after contamination. Concomitantly, BLM was secreted during the post contamination of poultry eggs with 100% EI24. Further by trying to show the pathogenicity by the hemolysis test, we have shown that SES and SCS were able to show significant areas of lysis on blood agar. Finally, this work has proposed an additional model of cell invasion including biosurfactants during the pre- and post-invasion phases.展开更多
The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This...The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This work aimed to assess prevalence of beta-lactamase produced by enterobacterial isolates. Then, disc diffusion, double disc synergy test (DDST) and combined disc test (CDT) were respectively used for antimicrobial resistance, detection of Extended-Spectrum Beta-Lactamases (ESBL) and Metallo-Beta-Lactamases (MBL). bla genes were detected by PCR. A total of 132 enterobacterial strains were studied. Resistance to antibiotic families was observed with a greater frequency than 50%. Gentamicin was the least active beta-lactam antibiotic, with a resistance rate of 88%. 40.9% of strains show an ESBL phenotype and 16.6% were MBL. An overall prevalence of 74% (40/54) and respectively rates of 29.6%, 27.7% and 16.7% for blaSHV, blaCTX and blaTEM genes were observed. SHV, CTX, CTX/SHV/TEM, CTX/TEM, SHV/TEM and CTX/SHV were different ESBL genotypes observed. ESBL-producing enterobacteria isolation worried about the future of antimicrobial therapy in the Republic of Congo. This is a public health problem that requires careful monitoring and implementation of a policy of rational antibiotics use.展开更多
Fermented beverages have continued to give more surprises in terms of the presence of biomolecules and the diversity of microorganisms that may be contained. Republic of Congo is home to a panoply of fermented foods a...Fermented beverages have continued to give more surprises in terms of the presence of biomolecules and the diversity of microorganisms that may be contained. Republic of Congo is home to a panoply of fermented foods and beverages that are still not yet studied. This is the case of plantain wine fluently called banana wine. Within this framework, this work aims to study the role of Biosurfactant-like Biomolecules secreted during fermentation of plantain wine. Using MRS medium, 15 isolates bacteria have been found. 100% are able to secrete biosurfactant and 66.66% are extractible biosurfactants. 33% of isolates have been associated to Lactobacillus plantarum (Is2, Is9, Is12 and Is13) by using a one-step multi-plex PCR that targets genes encoding for bacteriocins. Biosurfactants secreted by L. plantarum play an important role in the preservation of banana wine. The biosurfactants extracted with chloroform and ammonium sulphate are able to inhibit the growth of pathogenic bacteria including Shigella flexneri, Salmonella spp., Pseudomonas aeruginosa and Staphy-lococcus aureus.展开更多
Many high-reading journals reject several studies based on the basic aspects of microbiology by forgetting that this could open doors and windows of great scientific discoveries. A new spore-forming bacteria species c...Many high-reading journals reject several studies based on the basic aspects of microbiology by forgetting that this could open doors and windows of great scientific discoveries. A new spore-forming bacteria species called Lysinibacillus louembei has been previously discovered in our research unit. This new study aims to assess a real enzymatic machine produced with such bacteria. Using agarose mixed with half skimmed milk, LB medium supplemented with tween 20, Olive oil, egg yolk, cellulose, casein, pectin and starch, we showed that L. louembei has lipolytic, proteolytic (2.8 cm ± 0.1), cellulolytic, amylolytic pectinolytic activities, with percentage ranging from 30% to 80%. This species is able to secrete lipase, thermostable protease up to 60°C. Cellulase, pectinase and amylase are secreted with more stability between 30°C and 50°C with an optimum at 45°C. The effect of pH was determined after 24 h of incubation at 37°C and 50°C. The proteolytic activity is stable at pH 8 at 50°C. In addition to this first enzymatic landscape, L. louembei is able to degrade and/or tolerate gasoline and/or diesel fuel hydrocarbons in 36 hours. In this work, we also showed that L. louembei can produce biosurfactant in the presence of gasoline and SAE140 with the E24 up to 50%.展开更多
文摘According to the World Health Organization, foodborne diseases are a major public health problem, particularly in developing countries including the Republic of Congo. They are responsible for several episodes of diarrhea, especially in children under five years old. There is no reliable epidemiological data on the pathogenicity of the Shigella spp. strains circulating in the whole Republic of Congo drafting this paper. The purpose of this study was to examine the Shigella spp strain pathogenicity close to an environment contaminated with faeces in the city of Brazzaville. As a result, 54 isolates have been associated with Shigella spp. The gastric acid resistance test performed on Shigella Environmental Strain (SES) and Shigella Clinical Strains (SCS) resulted in 38.8% (21/54) and 100% acid resistant, respectively. Shigella spp. Strains (SES and SCS) were ranged in a survival percentage from 11% to 93%. By monitoring Biosurfactant-Like Molecule (BLM) production, we showed that the BLM production of SES and SCS was highly dependent on bacterial culture density involving the Quorum Sensing (QS). S. flexneri, S. boydii, and S. sonnei and as well as SES and SCS were able to invade and contaminate eggs by colonizing egg yolk. The counting bacteria were ranging from two to 5 × 10<sup>7</sup> CFU/mL after contamination. Concomitantly, BLM was secreted during the post contamination of poultry eggs with 100% EI24. Further by trying to show the pathogenicity by the hemolysis test, we have shown that SES and SCS were able to show significant areas of lysis on blood agar. Finally, this work has proposed an additional model of cell invasion including biosurfactants during the pre- and post-invasion phases.
文摘The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This work aimed to assess prevalence of beta-lactamase produced by enterobacterial isolates. Then, disc diffusion, double disc synergy test (DDST) and combined disc test (CDT) were respectively used for antimicrobial resistance, detection of Extended-Spectrum Beta-Lactamases (ESBL) and Metallo-Beta-Lactamases (MBL). bla genes were detected by PCR. A total of 132 enterobacterial strains were studied. Resistance to antibiotic families was observed with a greater frequency than 50%. Gentamicin was the least active beta-lactam antibiotic, with a resistance rate of 88%. 40.9% of strains show an ESBL phenotype and 16.6% were MBL. An overall prevalence of 74% (40/54) and respectively rates of 29.6%, 27.7% and 16.7% for blaSHV, blaCTX and blaTEM genes were observed. SHV, CTX, CTX/SHV/TEM, CTX/TEM, SHV/TEM and CTX/SHV were different ESBL genotypes observed. ESBL-producing enterobacteria isolation worried about the future of antimicrobial therapy in the Republic of Congo. This is a public health problem that requires careful monitoring and implementation of a policy of rational antibiotics use.
文摘Fermented beverages have continued to give more surprises in terms of the presence of biomolecules and the diversity of microorganisms that may be contained. Republic of Congo is home to a panoply of fermented foods and beverages that are still not yet studied. This is the case of plantain wine fluently called banana wine. Within this framework, this work aims to study the role of Biosurfactant-like Biomolecules secreted during fermentation of plantain wine. Using MRS medium, 15 isolates bacteria have been found. 100% are able to secrete biosurfactant and 66.66% are extractible biosurfactants. 33% of isolates have been associated to Lactobacillus plantarum (Is2, Is9, Is12 and Is13) by using a one-step multi-plex PCR that targets genes encoding for bacteriocins. Biosurfactants secreted by L. plantarum play an important role in the preservation of banana wine. The biosurfactants extracted with chloroform and ammonium sulphate are able to inhibit the growth of pathogenic bacteria including Shigella flexneri, Salmonella spp., Pseudomonas aeruginosa and Staphy-lococcus aureus.
文摘Many high-reading journals reject several studies based on the basic aspects of microbiology by forgetting that this could open doors and windows of great scientific discoveries. A new spore-forming bacteria species called Lysinibacillus louembei has been previously discovered in our research unit. This new study aims to assess a real enzymatic machine produced with such bacteria. Using agarose mixed with half skimmed milk, LB medium supplemented with tween 20, Olive oil, egg yolk, cellulose, casein, pectin and starch, we showed that L. louembei has lipolytic, proteolytic (2.8 cm ± 0.1), cellulolytic, amylolytic pectinolytic activities, with percentage ranging from 30% to 80%. This species is able to secrete lipase, thermostable protease up to 60°C. Cellulase, pectinase and amylase are secreted with more stability between 30°C and 50°C with an optimum at 45°C. The effect of pH was determined after 24 h of incubation at 37°C and 50°C. The proteolytic activity is stable at pH 8 at 50°C. In addition to this first enzymatic landscape, L. louembei is able to degrade and/or tolerate gasoline and/or diesel fuel hydrocarbons in 36 hours. In this work, we also showed that L. louembei can produce biosurfactant in the presence of gasoline and SAE140 with the E24 up to 50%.
