Microorganism: Pathogenic Bacteria

Introduction:

A microorganism is a microscopic living organism which is unicellular or multicellular. Microorganisms interact with human body continuously, but most tionof them do not cause any harm. Only few organisms are pathogenic to human beings. They may be a bacteria, virus, fungus or a parasite. Many of the bacteria are a part of the normal body flora and inhabit various areas in the body such as the oral cavity, nose, skin, nasopharynx, oropharynx, gastrointestinal tract, genitalia, urethra, vagina as well as the external ear. These organisms most of the time are non pathogenic, but in some cases especially in immunosuppressed patients, they may cause diseases. Bacteria that can cause infection are called pathogenic bacteria. Examples

Morphology: The morphological aspects which have to be taken into account before characterising the nanoparticles are the flatness, spherical nature and the aspect ratio i.e the ratio of the length and the breadth of the particle. Based on the shape of the nanoparticles, they have been given different names like nanospheres, nanoreefs, nanotubules, nanoboxes etc (Choy et al, 2004; Agam et al, 2007; Kralj, 2015;). Based on the aspect ratio, the nanoparticles are classified as high aspect ratio NP(HARN) and low aspect ratio NP(LARN). HARN are nanotubes, nanotubules, nanowires etc. LARN includes spherical, oval or ovoid, helical, prism and

Nanoparticles such as TiO2 and ZnO have been found to be used in cosmetics such as in sunscreens and in food products. Silver nanoparticles have found use in food packaging, disinfectants and clothing. Nanoparticles have also been used to disinfect drinking water and making it safe for drinking and also for removing bioaerosols from the air (Ireland et al, 1993; Gaswami et al, 1997; Byrne et al, 1998).

Nanoparticles are used in the field of medicine too. It has been used in fluorescent biological labels (Bruchez et al, 1998), drug and gene delivery (Mah, 2000), biodetection of pathogens (Edelstein et al, 2000), detection of proteins (Nam et al, 2003), probing of DNA structure (Mahtab et al, 1995) and tissue engineering (Ma et al, 2003), Tumour destruction via heating (Yoshida and Kobayashi, 1999), separation and purification of biological molecules and cells (Molday, and MacKenzie, 1982), MRI contrast enhancement (Weissleder et al, 1990) and phagokinetic studies are also some of the