Host response in urinary tract infections

Infections of the urinary tract have been studied extensively in man and in experimental animals since Kass first introduced the concept of quantitative bacteriological examination of the urine [1]. This procedure has allowed the ready identification of patients with significant bacterial growth in the urinary tract and has been used to explore the relationship of bacteriuria to the development of chronic pyelonephritis. Bacteriuria in the female is common with infections of the urinary tract accounting for 1.8% of all new consultations in a survey of general practice in New Zealand, compared with 0.2% for all other diseases of the kidney (D. J. A. Gallagher, personal communication, 1973). In contrast to this high morbidity from infections of the urinary tract, terminal renal failure from chronic pyelonephritis is not common [2, 3] and the relationship of this condition to bacterial invasion of the kidney has been seriously questioned [4]. The frequency of bacterial invasion of the kidney [5–7] and the relative infrequency of significant pathologic lesions in the kidney is a reflection of the host's response to infection which will be examined in detail in this review