The use and interpretation of microbiological cultures in family practice.

Microbiological cultures form an essential part of the diagnosis of infections but are secondary to a thorough history and examination. Familiarity with the role of the laboratory, including its limitations, is essential. Frequent consultations with the microbiologist help in the care of patients with difficult infections. Specimens can be divided into those taken from usually sterile sites and those from sites with normal bacterial flora. The latter will often pose problems in the interpretation of results, particularly when potential pathogens may occur in some patients as harmless commensals. Only well-taken and correctly processed specimens, together with clinical correlation of the results, will minimize errors in diagnosis.