Speciale A, Blandino G, Nicoletti G
Institute of Microbiology, University of Catania, Italy.
J Chemother. 1995 May;7 Suppl 1:9-12.
In order to provide additional data on the in vitro antibacterial activity of cefetamet-pivoxil against respiratory pathogens, we determined the bactericidal kinetics of this antibiotic in comparison to cefixime and ceftibuten against H. influenzae, M. catarrhalis, K. pneumoniae, E. coli, S. pneumoniae and S. pyogenes. time-kill studies were performed by using concentrations equal to a x MIC, and 4 x MIC of the antibiotics tested and different inocula (10(5), 10(7) and 10(9) CFU/ml). The strains were incubated in a shaking incubator at 37 degrees C and 1 ml samples were removed at regular intervals for viable count determination. The antibiotics were eliminated by serial ten-fold dilutions in physiological saline before plating. At 4 x MIC of cefetamet and at 10(5) CFU/ml inoculum the results were 99.9% killing or more of H. influenzae and M. catarrhalis at 4 h, and of E. coli and K. pneumoniae within 4 to 6 h, and of E. coli and K. pneumoniae within 4 to 6 h. At the same concentration of MIC and with the same inoculum a 99.9% reduction was achieved against S. pneumoniae within 4 h and against S. pyogenes within 2 h with no regrowth at 24 h in both cases. Similar results were obtained using 10(7) and 10(9) CFU/ml inocula. Cefetamet had efficient killing activity even at lower concentrations. Bactericidal kinetics of cefetamet favorably compare with those of cefixime and ceftibuten. The efficient bactericidal activity of cefetamet-pivoxil indicates a clinical role for this new oral cephalosporin in the treatment of respiratory tract infections.
为了提供头孢他美酯对呼吸道病原体体外抗菌活性的更多数据，我们测定了该抗生素与头孢克肟和头孢布烯相比，对流感嗜血杆菌、卡他莫拉菌、肺炎克雷伯菌、大肠杆菌、肺炎链球菌和化脓性链球菌的杀菌动力学。通过使用等于抗生素测试浓度的1倍MIC和4倍MIC以及不同接种量（10⁵、10⁷和10⁹CFU/ml）进行时间-杀菌研究。将菌株在37℃的振荡培养箱中培养，定期取出1ml样品进行活菌计数测定。在接种平板前，通过在生理盐水中连续十倍稀释来去除抗生素。在头孢他美4倍MIC和接种量为10⁵CFU/ml时，结果显示在4小时时对流感嗜血杆菌和卡他莫拉菌的杀灭率达到99.9%或更高，对大肠杆菌和肺炎克雷伯菌在4至6小时内达到此杀灭率。在相同的MIC浓度和相同接种量下，对肺炎链球菌在4小时内达到99.9%的减少率，对化脓性链球菌在2小时内达到此减少率，两种情况下在24小时均无再生长。使用10⁷和10⁹CFU/ml接种量也获得了类似结果。头孢他美即使在较低浓度下也具有有效的杀菌活性。头孢他美的杀菌动力学与头孢克肟和头孢布烯相比具有优势。头孢他美酯的有效杀菌活性表明这种新型口服头孢菌素在治疗呼吸道感染中具有临床作用。
