Metal Stress and Antibiotic Susceptibility Profile of Some Bacterial and Fungal Strains

In this study the effect of metal stress and antibiotics was evaluated on pathogenic strains of bacteria and fungi, due to an alarming rate of diseases caused by emergence of multi drug resistant pathogenic microorganisms and patients, untreated due to lack of appropriate drugs. The study was performed by standard Kirby Bauer Disk diffusion method approved by National Committee on Clinical Laboratory Standards (NCCLS) and broth dilution method. The inhibitory effect was analyzed by calculating Zone of inhibition (ZOI), minimum inhibitory concentration (MIC) and minimum bactericidal/ fungicidal concentrations (MBC/MFC) values. Antibiotic ceftriaxone (ZOI=20±2mm, MIC=250-315µg/ml and MBC≤2.5µg/ml) at concentration of ≥1000µg/ml, gentamycin (ZOI=19±2mm, and MBC=2.5µg/ml) and tetracycline (ZOI=19±2mm, MIC=250-315µg/ ml and MBC≤ ≤ ≤ ≤ ≤1.5±0.5 µg/ml) at ≥ ≥ ≥ ≥500µg/ml were most effective against Pseudomonas aeruginosa, Klebsiella pneumoniae, Citrobacter freundii, Micrococcus luteus, Staphylococcus aureus, Escherichia coli and Rhizopus stolonifer, Microsporum gyseum. While gentamycin (MIC=10mg/ml and MFC=10mg/ml) and tetracycline (MIC=20mg/ml) were also found to be most effective against fungus R. stolonifer, M. gyseum and P. crysogenum. The metal stress also significantly contributed in the inhibition of growth of bacterial strains as compared to the fungal strains. Cr 2+ and Cu 2+ at concentration of