各種抗生剤の最小発育阻止濃度におよぼす尿pHおよび菌量の影響

Abstract

In the case of chemotherapy of the urinary tract infection, the influence of urinary pH upon drug effect was investigated. Children with Urinary tract infection were subjected for this study. Antibacterial effect of drug or on sensibility of drug for bacteria was studied by changing pH of the medium which is normally used for sensitivity test by means of minimal inhibitor concentration (MIC) for bacteria, and furthermore the influence of inoculated bacterial count was also studied. 1) In 1609 cases, the urinary pH ranged between 4.6 and 8.0 and the average was 5.94. Among these cases, the average urinary pH of patients with urinary tract infection was 5.89, while the average urinary pH of patients without urinary tract infection was 5.98. In the cases of Proteus infection, the average urinary pH was 6.8 in acute period and was 6.0 in recovery period, but the average over 7.0 was not noticed. The changes of the daily urinary pH of the patients of the urinary tract infection of children was within 1.1. 2) The influence of pH of the medium at the time of MIC measurement was studied by adjusting of pH at 5, 6, 7 or 8. Among the examined 41 strains except one, any bacterial growth was not observed with-out antibiotics if pH was adjusted at 5. Growth inhibitory effect by pH itself was noticed. 3) As to CEZ, ABPC, MPC and GM, we measured the MIC for E.coli, Proteus, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus for each drug by changing pH of the medium and bacterial count. The result: a) The group in which pH of the medium increased antibacterial effect in alkaline side includes GM for various bacteria like E.coli., Proteus, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus and MPC for Staphylococcus aureus. Among these, MPC for Staphylococcus aureus showed the contrary phenomenon to the previous concept that acid material usually decreases its antibacterial effect in alkaline side. The group in which antibacterial effect was increased in the acid side, includes CEZ and ABPC for E. coli, Proteus, Pseudomonas aeruginosa, and MPC for E. coli. The group in which effect was not influenced by pH, includes CEZ and ABPC for Serratia marc esc ens, Staphylococcus aureus and MPC for Proteus, Pseudomonas aeruginosa and Serratia marcescens. b) As to relationship between inoculated bacterial count and MIC, each of combinations such as CEZ for proteus, ABPC for E.coli, Proteus, MPC for E.coli, Proteus, Staphylococcus aureus and GM for E. coli, Proteus, Staphylococcus aeruginosa showed increased MIC along with increase of bacterial count. In other combinations, the influence of inoculated bacterial count was not noticed clearly.