Bacterial persistence and expression of disease.

A considerable body of experimental and clinical evidence supports the concept that difficult-to-culture and dormant bacteria are involved in latency of infection and that these persistent bacteria may be pathogenic. This review includes details on the diverse forms and functions of individual bacteria and attempts to make this information relevant to the care of patients. A series of experimental studies involving host-bacterium interactions illustrates the probability that most bacteria exposed to a deleterious host environment can assume a form quite different from that of a free-living bacterium. A hypothesis is offered for a kind of reproductive cycle of morphologically aberrant bacteria as a means to relate their diverse tissue forms to each other. Data on the basic biology of persistent bacteria are correlated with expression of disease and particularly the mechanisms of both latency and chronicity that typify certain infections. For example, in certain streptococcal and nocardial infections, it has been clearly established that wall-defective forms can be induced in a suitable host. These organisms can survive and persist in a latent state within the host, and they can cause pathologic responses compatible with disease. A series of cases illustrating idiopathic conditions in which cryptic bacteria have been implicated in the expression of disease is presented. These conditions include nephritis, rheumatic fever, aphthous stomatitis, idiopathic hematuria, Crohn's disease, and mycobacterial infections. By utilizing PCR, previously nonculturable bacilli have been identified in patients with Whipple's disease and bacillary angiomatosis. Koch's postulates may have to be redefined in terms of molecular data when dormant and nonculturable bacteria are implicated as causative agents of mysterious diseases.

Bacterial variants in urinary casts and renal epithelial cells.

Casts with numerous and unusually large granules were seen in the urine of a child with renal Fanconi's syndrome. When the urine sediment was sealed under a coverslip for several days, many granules changed to filamentous bacterial variants that segmented and, finally, appeared as streptococcal-like forms. When the patient's blood was cultured by a special method, bacterial variants grew consistently, and frequently reverted to parent coccal forms, although conventional cultures were negative. Variants from blood cultures had the same morphology and staining properties as granules in casts and in cystic structures found within hypertrophied renal pelvic epithelial cells. Cryptic parasitization with bacterial variants probably occurs in many nephropathies. Variants are known to produce toxins and immunogens, which could lead to mesangial and basement membrane deposits as well as to occlusive reactions in the renal microcirculation.

Thyroid uptake of 131-I following kippuran renal scintillation camera studies in children.

The thyroid uptake of radioactive iodine after scintillation camera studies using -131I-labeled hippuran was studied and the radiation dose calculated in 30 euthyroid children with normal renal function. Fifteen children received Lugol's solution which reduced the thyroid uptake and radiation dose significantly.