Microarray analysis of pathogens and their interaction with hosts

Microarrays are a promising technique for elucidating and interpreting the mechanistic roles of genes in the pathogenesis of infectious disease. Micro arrays have been used to analyse the genetic polymorphisms of specific loci associated with resistance to antimicrobial agents, to explore the distrib ution of genes among isolates from the same and similar species, to underst and the evolutionary relationship between closely related species and to in tegrate the clinical and genomic data. This technique has also been used to study host-pathogen interactions, mainly by identifying genes from pathoge ns that may be involved in pathogenicity and by surveying the scope of the host response to infection. The RNA expression profile of pathogens has bee n used to identify regulatory mechanisms that ensure gene expression in the appropriate environment, to hypothesize functions of hundreds of uncharact erized genes and to identify virulence genes that promote colonization or t issue damage. This information also has the potential to identify targets f or drug design. Furthermore, microarrays have been used to investigate the mechanism of drug action and to delineate and predict adverse effects of ne w drugs. In this paper, we review the use of spotted and high-density oligo nucleotide arrays to study the genetic polymorphisms of pathogens, host-pat hogen interactions and whole-genome expression profiles of pathogens, as we ll as their use for drug discovery.