Morphological studies of Escherichia coli in the urine of patients with acute simple cystitis treated with aztreonam

Abstract

急性単純性膀胱炎の5症例にAztoreonam(AZT)を投与し, 透過型微分干渉顕微鏡を用いて大腸菌の形態学的変化について検討した.検体の尿はAZT1.Ogの静注前, 後5, 15, 30分にカテーテルを通して採取した.AZTに対する大腸菌の最小発育阻止濃度は0.05μg/mlであった.AZT投与後5, 15, 30分の尿中AZT濃度の平均は, それぞれ481.6μg/ml, 1168.2μg/ml, 993.4μg/mlであった.本剤投与後30分以内に5例中4例の尿所見は正常化していた.大腸菌の形態学的変化としては, フィラメント像がAZTの低濃度, 高濃度のいずれの場合にも観察された.またフィラメント化した大腸函の中には空胞様の変化が認められた, このような所見はAZTによる特徴的な形態変化であった.5例中1例の尿中にスフェロプラストや卵形細胞が観察された.これらの形態変化から急性単純性膀胱炎患者の尿においてAZTはペニシリン結合性蛋白質(PBP)3に強い新和性を有し, PBPlaに対しては中等度であると考えられた.

The effects of aztreonam (AZT) on the morphology of Escherichia coli in the urine of 5 patients with acute simple cystitis were studied by differential interference contrast microscopy. The urine specimens were collected via catheter before, 5, 15 and 30 minutes after intravenous administration of 1.0 gm AZT. The minimum inhibitory concentration of E. coli against AZT was 0.05 microgram/ml. The mean urinary concentrations at 5, 15 and 30 minutes after administration of AZT were 481.6 micrograms/ml, 1168.2 micrograms/ml and 993.4 micrograms/ml, respectively. In 4 patients, the urinalysis became normal within 30 minutes after the administration. Filamentous cells were observed at low and high urinary concentrations of AZT. They had vacuole-like formations. These findings were characteristic morphological changes caused by AZT. In the other patient, spheroplasts and ovoid cells were observed. AZT in the urine of patients with acute simple cystitis is suggested to have a high affinity for penicillin-binding protein (PBP) 3 and moderate affinity for PBP 1a.