Antibiotic susceptibility study Of metal-gentamicin complexes against Staphylococcus aureus biofilms

Introduction: Dental plaque is a structurally and functionally organized biofilm. Modern molecular biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be cultured. Inherent resistance of biofilm bacteria to conventional antibiotics is alarming. It induces antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Staphylococcus aureus is the most dominant bacterial species isolated from the saliva and dental plaques. One of the reasons for its pathogenicity is its ability to form biofilms. In this study, the resistance of S. aureus biofilms against a eries of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Materials and Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against several strains of S. aureus biofilms was conducted using broth microdilution assay. Results: The results showed that S. aureus is susceptible against Co(II) and Fe(II) gentamicin complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusion(s): Co(II) and Fe(II)-gentamicin complexes demonstrated antimicrobial activity

Antibiotic susceptibility study of metal-gentamicin complexes against Pseudomonas aeruginosa biofilms

Introduction: Inherent resistance of biofilm bacteria to conventional antibiotics is alarming because biofilms induce antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Pseudomonas aeruginosa is an infectious organism that causes the hallmark of chronic infections including hospital acquired infections that leads to high morbidity and mortality. One of the reasons for the occurrence of resistance is its ability to form biofilms. In this study, the resistance of P. aeruginosa biofilms against a series of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against the biofilms was conducted using broth microdilution assay. Results: The results showed that P. aeruginosa is susceptible against all the metal-gentamicin complexes, which include, Ni(II), Fe(II), Cu(II), Zn(II) and Co(II) complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusions: The results show that all metal-gentamicin complexes have higher antimicrobial activity than gentamicin (0.25 to 1 mmol) on its own. Finally, mechanisms of P. aeruginosa biofilms resistance to these metal-antibiotics are also proposed

Synthesis, characterization and antimicrobial studies of metal complexes derived from gentamicin sulfate

The emergence of antimicrobial resistance has reduced the potential of gentamicin, which is a broad-spectrum aminoglycoside antibiotic. Complexation of gentamicin with metal ions is expected to facilitate the antibiotic discovery process and would overcome the antimicrobial resistance. Five metal complexes, Cr(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes from gentamicin sulfate were successfully synthesized and characterized using decomposition point, elemental analyses, IR and UV–Vis spectroscopy. The results showed that all complexes have the general formula of [MLxLy.aH2SO4.bH2O], where M = metal ions (Cr, Co, Ni, Cu or Zn) and Lx = Ly = gentamicin ligand of either L1 = gentamicin C1 (C21H43N5O7) or L2 = gentamicin C2 (C20H41N5O7) or L3 = gentamicin C1a (C19H39N5O7). Characterization showed the presence of sulfuric acid molecules and coordinated water molecules in the metal complexes. Qualitative and quantitative antimicrobial assays were carried out to evaluate the biological activities of the parent compound and its metal complexes. It was found that all the complexes showed antimicrobial activity. The copper complex showed an increase of activity towards all the assayed microbial, while the chromium complex showed an enhanced activity with selectivity towards S. pyogenes and K. pneumonia

Antibiotic susceptibility study of metal-gentamycin complexes against pseudomonas aeruginosa biofilms

Inherent resistance of biofilm bacteria to conventional antibiotics is alarming because biofilms induce antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Pseudomonas aeruginosa is an infectious organism that causes the hallmark of chronic infections including hospital acquired infections that leads to high morbidity and mortality. One of the reasons for the occurrence of resistance is its ability to form biofilms. In this study, the resistance of P. aeruginosa biofilms against a series of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against the biofilms was conducted using broth microdilution assay. Results: The results showed that P. aeruginosa is susceptible against all the metal-gentamicin complexes, which include, Ni(II), Fe(II), Cu(II), Zn(II) and Co(II) complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusions: The results show that all metal-gentamicin complexes have higher antimicrobial activity than gentamicin (0.25 to 1 mmol) on its own. Finally, mechanisms of P. aeruginosa biofilms resistance to these metal-antibiotics are also proposed