**2.3 Importance of** *Acanthamoeba* **in nosocomial infections**

Recently, it is proposed that Acanthamoebae might play a role in the increased incidence of nosocomial infections (Michel*, et al.*, 1995, Marciano-Cabral & Cabral, 2003). It is well documented that Acanthamoebae act as natural vectors or reservoirs for a variety of microbes, such as *Escherichia coli, Klebsiella, Bacillus spp., Mycoplasma, Legionella pneumophila, Mycobacterium avium, Mycobacterium leprae, Clostridium frigidicarnis, Porphyromonas gingivalis, Prevotella intermedia, Burkholderia pseudomallei, Afipia felis, Vibrio cholerae, Mobiluncus curtissi, Campylobacter spp., Helicobacter pylori*, *Cryptococcus neoformans, Candida spp., Coxiella burnetti, Chlamydia, Rickettsia,* and Coxsackievirus among others (Marciano-Cabral & Cabral, 2003, Waldner*, et al.*, 2004, Khan, 2006, Mattana*, et al.*, 2006, Thomas*, et al.*, 2009). Bacteria grown in *Acanthamoeba* show resistance to bactericides and biocides; their survival and virulence are enhanced; and they mechanically transport disease-producing agents to various target organs, thus increasing the risk of multiple infections in the affected patients (King*, et al.*, 1988, Barker*, et al.*, 1995, Turner*, et al.*, 2000, Lloyd*, et al.*, 2001, Marciano-Cabral & Cabral, 2003). The amoebae shed waste through vesicles of 2.1 to 6.4 µm diameter, and they can potentially contain pathogenic microbes. For example, *A. polyphaga* can release up to 20 to 200 bacteria per vesicle and the vesicles can become aerosolized leading to their dispersal to wide-range of geographical locations (Rowbotham, 1980, Berk*, et al.*, 1998).
