RESEARCH PAPER Antibacterial potential of Al 2 O 3 nanoparticles against multidrug resistance strains of Staphylococcus aureus isolated from skin exudates Mohammad Azam Ansari • Haris M. Khan • Aijaz A. Khan • Ruchita Pal • Swaranjit Singh Cameotra Received: 16 April 2013 / Accepted: 23 August 2013 Ó Springer Science+Business Media Dordrecht 2013 Abstract To date very little studies are available in the literature on the interaction of Al 2 O 3 nano- particles with multidrug-resistant strains of Staphy- lococcus aureus. Considering the paucity of earlier reports the objective of present study was to investigate the antibacterial activity of Al 2 O 3 NPs ( \ 50 nm) against methicillin-resistant S. aureus and methicillin-resistant coagulase negative staphylo- cocci by various methods. Al 2 O 3 NPs were charac- terized by scanning electron microscopy, high- resolution transmission electron microscopy, and X-ray diffraction. The MIC was found to be in the range of 1,700–3,400 lg/ml. Almost no growth was observed at 2,000 lg/ml for up to 10 h. SEM micrograph revealed that the treated cells were significantly damaged, showed indentation on cell surface and clusters of NPs on bacterial cell wall. HR-TEM micrograph shows disruption and disorga- nization of cell membrane and cell wall. The cell membrane was extensively damaged and, most probably, the intracellular content has leaked out. Al 2 O 3 NPs not only adhered at the surface of cell membrane, but also penetrated inside the bacterial cells, cause formation of irregular-shaped pits and perforation on their surfaces and may also interact with the cellular macromolecules causing adverse effect including cell death. The data presented here are novel in that Al 2 O 3 NPs are effective bacteri- cidal agents regardless of the drug resistance mechanisms that confer importance to these bacteria as an emergent pathogen. Therefore, in depth studies regarding the interaction of Al 2 O 3 NPs with cells, tissues, and organs as well as the optimum dose required to produce therapeutic effects need to be ascertained before we can expect a more meaningful role of the Al 2 O 3 NPs in medical application. Keywords Al 2 O 3 NPs  Methicillin-resistant S. aureus  Methicillin-resistant coagulase negative staphylococci  Scanning electron microscopy  High-resolution transmission electron microscopy  X-ray diffraction M. A. Ansari (&)  H. M. Khan Nanotechnology and Antimicrobial Drug Resistance Research Laboratory, Department of Microbiology, Jawaharlal Nehru Medical College & Hospital, Aligarh Muslim University, Aligarh 202002, UP, India e-mail: azammicro@gmail.com A. A. Khan Department of Anatomy, Jawaharlal Nehru Medical College & Hospital, Aligarh Muslim University, Aligarh 202002, UP, India R. Pal Advanced Instrumentation Research Facility, Jawaharlal Nehru University, New Delhi, India S. S. Cameotra Institute of Microbial Technology (IMTECH), CSIR, Sector 39-A, Chandigarh 160036, India 123 J Nanopart Res (2013) 15:1970 DOI 10.1007/s11051-013-1970-1