The smothered fish samples were taken from 3 markets. They were grown on different selective and differentiated culture media to target groups of bacteria associated with food poisoning. Isolates were identified on th...The smothered fish samples were taken from 3 markets. They were grown on different selective and differentiated culture media to target groups of bacteria associated with food poisoning. Isolates were identified on the basis of cellular and colonial morphologies on selective and differentiated culture media, followed by susceptibility testing to certain families of antibiotics, in particular beta-lactams. This study showed that <em>S. aureus</em> and <em>B. cereus</em> had high levels of beta-lactam resistance. However, these strains were sensitive to kanamycin, tobramycin, ciprofloxacin and norfloxacin. The characteristic penicillinase phenotype was dominant in Gram-positive bacteria. <em>Shigella</em> spp, <em>Salmonella</em> spp and <em>E. coli </em>were resistant to beta-lactam antibiotics. Tobramycin and meropenem retained their activity on all strains. Despite the increased rates of resistance observed, vancomycin, kanamycin, tobramycin, gentamicin, ciprofloxacin, and norfloxacin can be used in the treatment of community-acquired infections caused by Gram-positive bacteria while meropenem and tobramycin for <em>Shigella</em> spp, <em>Salmonella</em> spp and<em> E. coli </em>infections.展开更多
Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT6746...Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulpha展开更多
Microorganisms are omnipresent in all environments and play mainly the role of transformers, thanks to the multiple enzymes they are able to produce. In order to valorize fermented foods in the Republic of the Congo, ...Microorganisms are omnipresent in all environments and play mainly the role of transformers, thanks to the multiple enzymes they are able to produce. In order to valorize fermented foods in the Republic of the Congo, this work aimed to characterize and study some properties of microorganisms isolated from samples of peppers sold in three markets of Brazzaville. A numeration of the total aerobic mesophilic flora (TAMF) was made in a solid medium, allowing the evaluation of each sample’s microbial concentration. The microbial mass varied from 2.8 × 105 CFU/g for the Ouénzé sample to 1.8 × 104 CFU/g for the Total sample and 2 × 104 CFU/g for the Moungali market sample. The evaluation of the enzymatic properties of the Bacillus isolates showed that 68.42% were capable of producing cellulases and 78.94% were capable of producing amylases and proteases. Antimicrobial activities revealed that 63.15% of the isolates were able to secrete inhibitory substances against E. coli and Staphylococcus aureus. Molecular analysis by PCR amplification, sequencing of the 16S rRNA gene and BLAST bioinformatics analysis provides newly identified bacteria strains with new accession numbers in GenBank: Bacillus thuringiensis MBCBR322 (OP474008), Bacillus megaterium MBCBJ1822 (OP476493), Bacillus thuringiensis MBCBR222 (OP476494), Priestia megaterium MBCBJ2022 (OP476495) and Lactobacillus paraplantarum MBCBR1522 (OP476496). Multiple sequences alignment of identified sequences with their homologs of GenBank has shown high similarities. The phylogenetic inference assay has provided the two groups of strains observed in this study, and the two groups are very coherent with the phylogeny of the reference.展开更多
文摘The smothered fish samples were taken from 3 markets. They were grown on different selective and differentiated culture media to target groups of bacteria associated with food poisoning. Isolates were identified on the basis of cellular and colonial morphologies on selective and differentiated culture media, followed by susceptibility testing to certain families of antibiotics, in particular beta-lactams. This study showed that <em>S. aureus</em> and <em>B. cereus</em> had high levels of beta-lactam resistance. However, these strains were sensitive to kanamycin, tobramycin, ciprofloxacin and norfloxacin. The characteristic penicillinase phenotype was dominant in Gram-positive bacteria. <em>Shigella</em> spp, <em>Salmonella</em> spp and <em>E. coli </em>were resistant to beta-lactam antibiotics. Tobramycin and meropenem retained their activity on all strains. Despite the increased rates of resistance observed, vancomycin, kanamycin, tobramycin, gentamicin, ciprofloxacin, and norfloxacin can be used in the treatment of community-acquired infections caused by Gram-positive bacteria while meropenem and tobramycin for <em>Shigella</em> spp, <em>Salmonella</em> spp and<em> E. coli </em>infections.
文摘Objective: The objective of the present study is to optimize cellulase production in five strains: (Pantoea dispersa MLTBY6 (MT646430.1);Pseudomonas aeruginosa MLTBM2 (MT646431.1);Pseudomonas monteilii MLTBC10 (MT674682.1);Bacillus subtilis MLTBC5 (MT674681.1) and Lysinibacillus fusiformis MLTBB7 selected cellulase producers isolated from soils in Brazzaville, Republic of the Congo. Materials and Methods: The cellulolytic activity of the selected cellulase-producing strains was determined by transferring the strains to a petri dish containing CMC culture medium with the following composition: cellulose 1%, K<sub>2</sub>HPO<sub>4</sub> 0.2%, MgSO<sub>4</sub> 0.03%, peptone 1%, (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> 0.2% adjusted to a pH value of 7, previously poured and then frozen. The dishes were incubated in an oven at 37°C for 48 hours. The petri dishes were then flooded with 1% lugol for 15 minutes. A positive reading is indicated by the formation of a hydrolysis zone, the diameters of the hydrolysis zone were measured with a ruler. Strains with a broad lysis spectrum were selected. Optimisation of cellulase production by five bacterial strains isolated from the soil was done using the following factors: temperature and pH. Results: The production of cellulase showed that these strains showed a high production of cellulase at pH values between 5.6 and 9 with an optimum of pH = 8 and temperature values between 35°C and 40°C with an optimum at temperature t = 40°C. Of the carbon sources used, two sources, namely glucose and galactose, showed a high production of cellulase compared to the other carbon sources. However, the two nitrogen sources, ammonium sulphate and urea, were favourable for cellulase production by all five strains. Fe<sup>2+</sup>, CO<sup>2+</sup>, Zn<sup>2+</sup> ions are favourable for cellulase production by these strains, with a referendum for Fe<sup>2+</sup>. Conclusion: From these results, we conclude that the sources of carbon (glucose and galactose), nitrogen (ammonium sulpha
文摘Microorganisms are omnipresent in all environments and play mainly the role of transformers, thanks to the multiple enzymes they are able to produce. In order to valorize fermented foods in the Republic of the Congo, this work aimed to characterize and study some properties of microorganisms isolated from samples of peppers sold in three markets of Brazzaville. A numeration of the total aerobic mesophilic flora (TAMF) was made in a solid medium, allowing the evaluation of each sample’s microbial concentration. The microbial mass varied from 2.8 × 105 CFU/g for the Ouénzé sample to 1.8 × 104 CFU/g for the Total sample and 2 × 104 CFU/g for the Moungali market sample. The evaluation of the enzymatic properties of the Bacillus isolates showed that 68.42% were capable of producing cellulases and 78.94% were capable of producing amylases and proteases. Antimicrobial activities revealed that 63.15% of the isolates were able to secrete inhibitory substances against E. coli and Staphylococcus aureus. Molecular analysis by PCR amplification, sequencing of the 16S rRNA gene and BLAST bioinformatics analysis provides newly identified bacteria strains with new accession numbers in GenBank: Bacillus thuringiensis MBCBR322 (OP474008), Bacillus megaterium MBCBJ1822 (OP476493), Bacillus thuringiensis MBCBR222 (OP476494), Priestia megaterium MBCBJ2022 (OP476495) and Lactobacillus paraplantarum MBCBR1522 (OP476496). Multiple sequences alignment of identified sequences with their homologs of GenBank has shown high similarities. The phylogenetic inference assay has provided the two groups of strains observed in this study, and the two groups are very coherent with the phylogeny of the reference.
