Journal of Pure and Applied MicrobiologyVol. 6 No. 4

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

Chandrabhan Seniya1*, Santosh Kumar Verma2, Sumint Singh Trivedia3, Richa Verma1, H.S. Vijayarti1 and Shridutt Vyas1

1Department of Biotechnology, Madhav Institute of Technology & Science, Gwalior - 474005, India. 2Department of Life Sciences, ITM University, Gwalior (M.P.) India 3Department of Chemical Engineering, Madhav Institute of Technology & Science Gwalior - 474 005, India.

Received on 28 March 2012 and accepted on 05 May 2012

 

ABSTRACT

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. Cr2+ and Cu2+ at concentration of ?40mg/ml gave highest antibacterial activity than other metal ions. The Cu2+ was observed to be toxic at concentration ?80mg/ml for bacteria. While Mn2+ found resistant against bacterial strains but it found to be most effective against all selected fungal strains at concentration of ?60mg/ml with ZOI>20mm. Zn2+ was also effective against fungal growth at concentration of ?80mg/ml but fails in the inhibition of growth of bacterial strains. The most prompting candidate order to inhibit the growth of fungal strains investigated in this study is as follows: Mn2+ > Zn2+ > Cu2+ > Cr2+ > Fe2+. This study suggests that metal ions may be used as antimicrobial/antifungal agents along with the antibiotics such as tetracycline, ceftriaxone and gentamicin and may be good drug of choice against bacterial and fungal pathogenesis in future.

Keywords : Antibacterial, Metal Stress, ZOI, MIC, MBC and MFC.