Relevance of "significant bacteriuria" to aetiology and diagnosis of urinary-tract infection.

28 of 74 female domiciliary patients who presented with urinary-tract symptoms did not fulfil the usually accepted laboratory criterion required for confirmation of urinary-tract infection (i.e., a urinary bacterial viable count in excess of 100 000/ml). The progress of the disease was similar in non-bacteriuric and bacteriuric patients. In addition, a significant proportion of the bacteriuric group did not show the response to therapy expected from the results of in-vitro tests of antibiotic sensitivity and urinary antibacterial activity. To explain these findings, it is postulated that bacteria may not be primary pathogens in uncomplicated urinary-tract infection even where "significant bacteriuria" is demonstrated.