ABSTRACT
In order to treat diseases caused by infectious agents optimally and appropriately, a working knowledge of the types and spectrum of microbes causing them is essential and crucial. This chapter in the book has been divided into bacteria including mycobacteria, viruses, prions, fungi and parasites. Because of the common and treatable (and often curable) nature of diseases caused by bacteria, this group of microbes has been described in more detail following the classic model of classifications based on gram stain characteristics and oxygen requirement for growth. The clinical implications of common infections caused by bacteria are summarized in a way that is helpful in understanding the diagnostic methodology provided in the next chapter. Viral pathogens are described in order of their clinical significance with emphasis on major treatable viral syndromes. Viruses against which highly effective vaccines have been available for decades are included since global eradication has not been achieved and a small but significant unvaccinated population even in resourceful countries like the US is at risk. The small section on prions focuses on the resistance of these “biological agents” to many standard procedures of decontamination and sterilization and their transmissibility through bovine meat products and medical interventions involving infected tissues. A summary of infectious diseases caused by different groups of fungi and parasites is provided in the next two sections.
