結石にともなう尿路感染症 1. 尿路感染の意義について

Abstract

尿路結石と尿路感染の関係を検討すべく尿路結石の手術症例について, 結石成分, 膿尿, 尿培養, 結石培養, 細菌のウレアーゼ活性などについて調べた.1)無菌性膿尿は感染結石では18%, 代謝結石では69%で, 細菌尿は感染結石で79%, 代謝結石で26%であった.2)結石内培養は感染結石で67%, 代謝結石で23%であった.尿培養の結石培養との菌種の一致率は感染結石49%, 代謝結石33%であった.このことは抗菌剤の使用時に特に留意すべきである.3)菌種は尿および結石培養とも感染結石ではウレアーゼ陽性菌のP. mirabilisが多く, 代謝結石ではウレアーゼ陰性のE. coliが多くみられた.4)感染結石では尿路感染の起炎菌は結石形成に直接的に働き, 代謝結石でそれは偶然付着し, 尿路感染を起しているものと思われる.代謝結石でのウレアーゼ陽性菌は代謝結石を感染結石に変化せしめる可能性が考えられる

We investigated 158 cases of urinary stones (infection stones 56, metabolic stones 102) with special reference to pyuria, bacteriuria, stone culture and urease activities of isolated bacteria. Abacterial pyuria was noted in 9 out of 49 (18%) infection stones and in 53 of 77 (69%) metabolic stones. Bacteriuria was noted in 79% of the infection stones and 26% of the metabolic stones. Sixty-seven percent of the infection stones were infected with mainly urea splitting bacteria such as Proteus mirabilis and Staphylococcus. Twenty-three percent of metabolic stones were also infected. Though E. coli, a non-urea splitting bacteria, was isolated most frequently from metabolic stones, urease positive Staphylococcus and Pseudomonas were also isolated. Bacteria within stones could be predicted on the basis of urine culture results of only 20 of 41 infection stones and 8 of 24 metabolic stones. These facts are useful for selection of some antibiotics in the treatment of urinary tract infections associated with urinary calculi. Urinary infections of urea splitting bacteria in infection stones are thought to be initial factors of stone formation and those of non-urea splitting bacteria are to be superimposed. However, urea splitting bacteria in metabolic stones may convert them into infection stones in future.