Much of the available data on the incidence of anaerobic infections is not reliable. Bacteriologic data without clinical correlation are not adequate… - Sydney M. Finegold

... (1) What is the clinical relevance of anaerobic bacteriology? (2) How can the microbiologist, with limited and decreasing resources, perform reliable, detailed studies of anaerobic bacteriology? (3) When and how should susceptibility testing be done with anaerobes? If the clinician knows the usual bacteriology of various types of infection and how this may be modified by pathophysiologic processes in the host or by prior therapy, he/she can use a logical empiric approach to treatment of the patient. As to the microbiologist's dilemma, it is not realistic or rational for a microbiologist in a nonteaching hospital to do detailed bacteriologic studies and routine anaerobic susceptibility testing. The resources available should be committed primarily to the patient who is seriously ill. Such allocation of resources, of course, requires repeated and effective communication between microbiologist and clinician.

Anaerobic bacteria produce many different enzymes that are of importance in providing nutrients to the bacterial cell, as virulence factors, and in permitting organisms to colonize or survive under adverse conditions (including exposure to antimicrobial agents). Some enzymes effect several types of modifications to bile acids, neutral steroids, and corticosteroids. Anaerobes are clearly important in a variety of infections in humans and animals as well as in various other types of pathologic processes.

The commonly used drugs that have a major effect on the colonic flora are ampicillin, cefoperazone, clindamycin and oral neomycin or kanamycin, used together with either tetracycline, erythromycin or metronidazole.