normal flora,pathogenicity of microorganisms,diagnostic microbiology,vaccines and antibiotics,bacteria,structure,growth,metabolism,bacterial genetics,gram-positive rods,spirochetes,mycoplasma,mycobacteria and actinomycetes,rickettsiae,fungi,protozoa,helminths,nonenveloped dna viruses,enveloped dna viruses,retroviruses and aids,unconventional infectious agents,clinically important microorganisms,