Comparative in-vitro activity of levofloxacin against Chlamydia spp.

one strain each and by trimethoprim for three strains were reduced (by 2, 6 and 6–7 mm, respectively) after incubation in a CO 2-containing atmosphere compared with those obtained following incubation in the aerobic atmosphere. None of the seven isolates was CO2dependent and in all cases, the susceptibility categories for the relevant antibiotics were downgraded from susceptible in the aerobic atmosphere to intermediate susceptibility in the CO2-containing atmosphere. The results of this study demonstrate that most pneumococcal and H. influenzae isolates will grow aerobically on primary culture and that CO 2-dependent pneumococci and H. influenzae grow adequately in either a candle or huff jar. In addition, when determining the susceptibilities of pneumococci to oxacillin, erythromycin, trimethoprim and tetracycline, accurate results are obtained for the majority of pneumococci without relying on incubation in an atmosphere containing 5% CO 2. On the basis of this evidence, it is questionable whether CO 2 incubators are necessary for culturing sputum samples when cheaper and equally effective options are readily available.