Résumé
Abstract In the present work, twelve bacilli were isolated from four different regions of human skin from Bela population of Nagpur district, India. The isolated bacilli were identified by their morphological, cultural and biochemical characteristics. Seven isolates were Gram negative rods, out of which five were belong to genus Pseudomonas. Three among the five Gram positive isolates were identified as Dermabactor and the remaining two Bacillus. Their antimicrobial susceptibility profile was determined by Kirby-Bauer disc diffusion method. The isolates showed resistance to several currently used broad-spectrum antibiotics. The Dermabactor genus was resistant to vancomycin, although it was earlier reported to be susceptible. Imipenem was found to be the most effective antibiotic for Pseudomonas while nalidixic acid, ampicillin and tetracycline were ineffective. Isolates of Bacillus displayed resistance to the extended spectrum antibiotics cephalosporin and ceftazidime. Imipenem, carbenicillin and ticarcillin were found to be the most effective antibiotics as all the investigated isolates were susceptible to them. Antibiotic resistance may be due to the overuse or misuse of antibiotics during the treatment, or following constant exposure to antibiotic-containing cosmetic formulations.
Sujets)
Adolescent/classification , Adolescent/effets des médicaments et des substances chimiques , Adolescent/génétique , Adolescent/isolement et purification , Adolescent/microbiologie , Adolescent/pharmacologie , Adulte/classification , Adulte/effets des médicaments et des substances chimiques , Adulte/génétique , Adulte/isolement et purification , Adulte/microbiologie , Adulte/pharmacologie , Antibactériens/classification , Antibactériens/effets des médicaments et des substances chimiques , Antibactériens/génétique , Antibactériens/isolement et purification , Antibactériens/microbiologie , Antibactériens/pharmacologie , Bacillus/classification , Bacillus/effets des médicaments et des substances chimiques , Bacillus/génétique , Bacillus/isolement et purification , Bacillus/microbiologie , Bacillus/pharmacologie , Femelle/classification , Femelle/effets des médicaments et des substances chimiques , Femelle/génétique , Femelle/isolement et purification , Femelle/microbiologie , Femelle/pharmacologie , Volontaires sains/classification , Volontaires sains/effets des médicaments et des substances chimiques , Volontaires sains/génétique , Volontaires sains/isolement et purification , Volontaires sains/microbiologie , Volontaires sains/pharmacologie , Humains/classification , Humains/effets des médicaments et des substances chimiques , Humains/génétique , Humains/isolement et purification , Humains/microbiologie , Humains/pharmacologie , Mâle/classification , Mâle/effets des médicaments et des substances chimiques , Mâle/génétique , Mâle/isolement et purification , Mâle/microbiologie , Mâle/pharmacologie , Tests de sensibilité microbienne/classification , Tests de sensibilité microbienne/effets des médicaments et des substances chimiques , Tests de sensibilité microbienne/génétique , Tests de sensibilité microbienne/isolement et purification , Tests de sensibilité microbienne/microbiologie , Tests de sensibilité microbienne/pharmacologie , Adulte d'âge moyen/classification , Adulte d'âge moyen/effets des médicaments et des substances chimiques , Adulte d'âge moyen/génétique , Adulte d'âge moyen/isolement et purification , Adulte d'âge moyen/microbiologie , Adulte d'âge moyen/pharmacologie , Peau/classification , Peau/effets des médicaments et des substances chimiques , Peau/génétique , Peau/isolement et purification , Peau/microbiologie , Peau/pharmacologie , Jeune adulte/classification , Jeune adulte/effets des médicaments et des substances chimiques , Jeune adulte/génétique , Jeune adulte/isolement et purification , Jeune adulte/microbiologie , Jeune adulte/pharmacologieRésumé
Abstract A total of 48 endophytic bacteria were isolated from surface-sterilized tissues of the medicinal plant Lonicera japonica, which is grown in eastern China; six strains were selected for further study based on their potential ability to promote plant growth in vitro (siderophore and indoleacetic acid production). The bacteria were characterized by phylogenetically analyzing their 16S rRNA gene similarity, by examining their effect on the mycelial development of pathogenic fungi, by testing their potential plant growth-promoting characteristics, and by measuring wheat growth parameters after inoculation. Results showed that the number of endophytic bacteria in L. japonica varied among different tissues, but it remained relatively stable in the same tissues from four different plantation locations. Among the three endophytic strains, strains 122 and 124 both had high siderophore production, with the latter showing the highest phosphate solubilization activity (45.6 mg/L) and aminocyclopropane-1-carboxylic acid deaminase activity (47.3 nmol/mg/h). Strain 170 had the highest indoleacetic acid (IAA) production (49.2 mg/L) and cellulase and pectinase activities. After inoculation, most of the six selected isolates showed a strong capacity to promote wheat growth. Compared with the controls, the increase in the shoot length, root length, fresh weight, dry weight, and chlorophyll content was most remarkable in wheat seedlings inoculated with strain 130. The positive correlation between enzyme (cellulose and pectinase) activity and inhibition rate on Fusarium oxysporum, the IAA production, and the root length of wheat seedlings inoculated with each tested endophytic strain was significant in regression analysis. Deformity of pathogenic fungal mycelia was observed under a microscope after the interaction with the endophytic isolates. Such deformity may be directly related to the production of hydrolytic bacterial enzymes (cellulose and pectinase). The six endophytic bacterial strains were identified to be Paenibacillus and Bacillus strains based on the results of 16S rRNA gene sequencing analysis and their physiological and biochemical characteristics. Results indicate the promising application of endophytic bacteria to the biological control of pathogenic fungi and the improvement of wheat crop growth.