新氨基糖苷类抗生素89—07体外抗菌作用研究

In vitro antibacterial activity of antibiotic 89-07,a new aminoglycoside

用琼脂二倍稀释法研究了抗生素８９－０７的体外抗菌作用。共测定临床分离茵１１０６株，其中革兰氏阴性杆菌７８０株，革兰氏阳性球菌３２６株。６种氨基糖苷类、２种β－内酰胺类与１种喹诺酮类抗菌药物用作对照，研究结果表明：抗生素８９—０７抑制半数以上致病菌的ＭＩＣ≤ｌｍｇ／Ｌ；对庆大霉素、小诺米星和头孢唑林耐药的金葡球菌以及大肠杆菌的ＭＩＣ５０为８ｍｇ／Ｌ；对头孢唑林耐药的克雷伯氏肺炎杆菌的ＭＩＣ５０为０．５ｍｇ／Ｌ。抑制６６％的甲氧西林耐药金葡球菌所需抗生素８９－０７的浓度为０．５～８ｍｇ／Ｌ这些结果说明上述半数以上耐药菌对抗生素８９—０７敏感的浓度在其安全有效的血药浓度范围之内，该浓度低于１９９３年ＮＣＣＬＳ规定的奈替米星的敏感临界浓度（≤１２ｍｇ／Ｌ）。抗生素８９－０７对多数敏感菌的最低杀菌浓度（ＭＢＣ）为ＭＩＣ值的２～４倍。细菌接种量对其体外抗菌活性无明显影响。抗菌作用的最佳ｐＨ值为７．８～８．０。

A total of 1106 clinical isolates including 780 strains of Gram-negativebacilli and 326 strains of Gram-positive cocci were tested using agar dilution method forevaluating in-vitro antibacterial activity of antibiotic 89-07, a new aminoglycoside developedin China,compared with that of nine other antimicrobial agei1ts incltiding six aminoglyco-sides,two β-lactams and one of fluoroquinolone More than half of the test strains were inhibited by 1 mg/Lor less of antibiotic 89-07。50%of gentamicin-resistant, micronomicin-resistant and cefazolin-resistant strains of S。aureus and E, coli were still susceptible to antibiotic 89-07 at a concentration of 8 mg/L。MIC50 of antibiotic 89-07 against cefazolin-resistant Klebsiella pneumoniae was 0. 5 mg/Land 66%strains of MRSA were inhibited by 0.5～8mg/L of antibiotic 89-07. Resultsshowed that more than half of above mentioned resistant strains were susceptible toantibiotic 89-07 at a safe and effective concentration lower than stisceptible MIC breakpoint(≤12mg/L)of netilmicin according to the NCCLS standards(1993) The MBCs of antibiotic 89-07 ranged from two～four times the MICs and the inoculumsize has little effect on the MICs of antibiotic 89-07. pH7.8～8. 0 was the optimal pH valuefor antibacterial activity of atitibiotic 89-07 against the test isolates;