ABSTRACT
Pollution due to the heavy metals is a problem that may have negative consequences on the hydrosphere. Identification of microorganisms resistant to heavy metals plays an important role in relation to environmental pollution bioremediation. This study was done to assess the antibiotic resistance in isolated bacteria from urban sewage and copper smeltery industrial wastewater. This laboratory study was done on the wastewater samples from urban sewage and copper smeltery in Isfahan-Iran, during 2011-12. Heavy metal resistant microorganisms were isolated and enumerated after serial dilution and culturing on PHG agar plates supplemented with 0.5 mM of each heavy metal. The pattern of resistance was assigned by Minimum Inhibitory Concentration [MIC]. Antibiotic resistance toward following medicines Ofloxacine, Penicilline, Sulfometoxasole, Lincomycin, Kanamycin, Streptomycin, Clindamycin, Vancomycin, Cefradin and Neomycin were subsequently investigated. The greatest resistance in isolated bacteria has been related to the Ni [MIC: 24 mM] that's related to the genus of Klebsiella and its minimum MIC is 2mM that's of Acinetobacter lwoffi, Providencia stuartii, Branhamella. The minimum degree of resistance is related to Cu. Its Maximum MIC related to this metal in swage is 2 mM that's of Klebsiella pneumoniae and its minimum degree of resistance in copper smeltery effluent is arranged as 1mM related to genus of Pseudomonas alkaligenes. In examining multi metal resistance pattern, the greatest resistance with 8 mM MIC has been related to the Cd, that's of Ni resistant Moraxella osloensis in Copper smeltery effluent. The highest portion of isolated bacteria were resistant to Pb [P<0.05]. The highest resistance of refirary wastewater was to Ni [MIC: 2 mM], which belong to Klebsiella [P<0.05]. The lowest belong to Acine to bacter Lwoffi providencia Stuartii, Branhamella [MIC: 2mM] [P<0.05]. In urban sewage: the highest resistance belong to copper, which was seen in Klebsiella Pneumoniae [MIC: 2mM]. In Antibiogram tests of Klebsiella, Moraxella and Escherichia, it was demonstrated that the metal resistant bacteria were also resistant toward Lincomycin, Kanamycin, Streptomycin, Clindamycin, Vancomycin, Cefradin and Neomycin, as well. Increasing heavy metal resistance in the environment leads to increased antibiotic resistance toward microorganisms
ABSTRACT
Oral Streptococci especially Streptococcus mutans are the major cause of dental caries and periodontal diseases. Going along with the increasing antibiotic resistance of bacteria, new methods for decreasing of oral cavity pathogens must be investigated. The aim of this study was to determine the effect of lactobacillus fermentum ATCC9338 as a probiotic strain on the adhesion of oral streptococci to the surfaces. S. mutans ATCC35668 with oral streptococci isolated from dental plaque and caries [40 isolates] were studied. The ability of biofilm formation was investigated using the colorimetric method. An isolates showing the strongest activity in forming biofilm were selected. Then the effect of probiotic strain on the adhesion of the selected isolate to the polystyrene microtiter plate was determined simultaneously and 30 minutes before streptococci entrance to the system. This study showed that in the presence of probiotic strain, the streptococcal adhesion were reduced, and this reduction was significantly stronger if the probiotic strain was inoculated to the system before the oral bacteria. Adhesion reduction is likely due to bacterial interactions and colonization of adhesion sites with probiotic strain before the presence of streptococci. Adhesion reduction can be an effective way on decreasing cariogenic potential of oral streptococci