Yourassowsky E, Van der Linden M P, Lismont M J, Crokaert F, Glupczynski Y
Pathol Biol (Paris). 1986 May;34(5):381-4.
The antibacterial activity of beta-lactams against H. influenzae is difficult to evaluate as a result of the osmotic-pressure-dependent formation of filaments and spheroplasts whose viability is still under debate. We compared growth curves obtained by optic density measurements and by UFC/ml counts for H. influenzae in the presence of amoxicillin, cefaclor and cefotaxime in various concentrations. Only the early response to antibiotics, observed during the first six hours of antibiotic-culture contact, was considered. Results showed, for each of the three antibiotics: an increase in optic density with formation of abnormal organisms that correlated poorly with antibiotic concentrations; a stable number of UFC/ml for more than 90 mn, followed by a slow fall reaching at the most 1.5 Log 10 UFC/ml at the sixth hour. We conclude that amoxicillin, cefaclor and cefotaxime in active concentrations rapidly produce the formation of abnormal organisms with an increase in biomass as a result. These abnormal organisms lose their viability slowly, even with concentrations greater than 50 time the MIC. Cefaclor's MIC and MBC are underestimated when results are read only after 24 hours.
由于渗透压依赖性的丝状菌和原生质球的形成，其生存能力仍存在争议，因此很难评估β-内酰胺类药物对流感嗜血杆菌的抗菌活性。我们比较了在不同浓度的阿莫西林、头孢克洛和头孢噻肟存在下，通过光密度测量和每毫升菌落形成单位（CFU/ml）计数获得的流感嗜血杆菌生长曲线。仅考虑在抗生素与培养物接触的前六个小时内观察到的对抗生素的早期反应。结果显示，对于这三种抗生素中的每一种：光密度增加，同时形成与抗生素浓度相关性较差的异常生物体；在90多分钟内每毫升CFU数量稳定，随后缓慢下降，在第六小时最多降至1.5个对数10CFU/ml。我们得出结论，活性浓度的阿莫西林、头孢克洛和头孢噻肟会迅速导致异常生物体的形成，从而使生物量增加。这些异常生物体的生存能力缓慢丧失，即使浓度高于最低抑菌浓度（MIC）的50倍。如果仅在24小时后读取结果，头孢克洛的MIC和最低杀菌浓度（MBC）会被低估。
