IgA nephropathy is the commonest form of chronic glomerular disease. The clinical manifestation of this disorder suggests an association with upper respiratory tract infections. Recently it has been reported that Haemophilus parainfluenzae has a role in the etiology of IgA nephropathy. Therefore, the relationship between glomerular disease and oral bacterial flora has attracted attention. Also, it is demonstrated that H. parainfluenzae can bind to high-molecular weight salivary mucins in a selective manner in humans. The present study focused on the changes in salivary bacterial flora, particular H. parainfluenzae species, with the progress of glomerular disease in patients with chronic glomerulonephritis (CGN), and chronic renal failure (CRF), and patients receiving hemodialysis (HD). With the progress of glomerular disease, the prevalence of Micrococcus, H. parainfluenzae, and Bacillus decreased, and the prevalence of Candida and CNS increased. The decrease in the prevalence of H. parainfluenzae was most remarkable. Serum complement (C3, C4, and CH50) levels decreased significantly in CRF and HD patients compared with those in CGN patients. Serum IgA levels in patients with H. parainfluenzae did not differ significantly from those in patient without H. parainfluenzae in each stage of glomerular disease. In conclusion, salivary bacterial flora changes with the progress of glomerular disease. The overwhelming prevalence of H. parainfluenzae in the stage of CGN compared with the stages of CRF and HD, may support the hypothesis that H. parainfluenzae has a role in the etiology of chronic glomerulonephritis.

It is known that lactic acid bacteria preparations suppress the intestinal putrefaction and improves defecation, and that lactulose acidifies the intestinal contents and stimulates the proliferationof lactic acid bacteria in the intestines and further inhibits the absorption of ammonia from the intestine, resulting in the decrease in the synthesis of urea in the liver. For this clinical study, 15 patients receiving maintenance hemodialysis were selected and were divided into two groups. They received orally either lactic acid bacteria preparations or lactulose earlier for 6 weeks, followed by administration of their combination for 6 weeks. We examined the effects of each administration on the changes in peripheral blood counts, blood chemistries, intestinal bacterial flora in a lower portion of the rectum and bowel habits. Administration of lactulose combined with lactic acid bacteria preparations following the intake of lactulose alone induced a significant decrease in the serum triglyceride levels and a significant increase in serum phosphate levels. However, administration of lactic acid bacteria preparations in combination with lactulose following the intake of lactic acid bacteria preparations alone induced no significant changes. Plasma levels of ammonia and glycohemoglobin remained unchanged. Administration of lactic acid bacteria preparation and lactulose and their combination induced the increase in the percentages of Streptococcus, Enterococcus and Staphylococcus groups in the lower portion of the rectum, whereas Candida albicans was not detected. The improvement of bowel habits was observed after administration of their combination rather than administration of lactic acid bacteria preparations and lactulose alone. These results suggest that the environmental changes of the intestine produced by administration of lactulose earlier than of the combination with lactic acid bacteria preparations are effective in changing blood chemistries, and that administration of their combination has advantages in improving the bowel habits.