Achieving the growth of H pylori in liquid media is of great

Achieving the growth of H. pylori in liquid media is of great SCH727965 importance in the development of clinical studies. In this study, we developed a sequential optimization strategy based on statistical models to improve the conditions of liquid culture of H. pylori. Materials and Methods:  Four statistical models were sequentially used. First, a Box-Behnken design was used to select the best process conditions (shaking speed, inoculum concentration, and final volume of culture). Secondly, a general factorial design was used to evaluate the influence of adding gel blocks or gel beads (shape and composition). Then a D-optimal reduce design was carried out to allow the selection of

the most influential factors in increasing the cell concentration (culture media components). Finally,

another Box-Behnken design was used to optimize the concentration of the culture media components previously selected. Results:  After 12 hours of liquid culture a concentration of 25 × 108 cells per mL (9.4 log10 cells per mL) of H. pylori was obtained, compared with a predicted 32 × 108 (9.5 log10 cells per mL), which means between 1 and 5 log10 units higher than some previous reports. Conclusions:  The sequential statistical approach increased the planktonic H. pylori cell culture. The final culture media and conditions selleck chemicals llc were: Brain Heart Infusion, blood agarose (1.5% w/v), lamb’s blood (3.18% v/v), DENT (0.11% v/v), and Vitox (0.52% v/v) at 60 rpm and 37 °C with filtered CO2 selleck screening library (5% v/v) bubbled directly into the culture media in a final volume of 76.22 mL. “
“Background:  The aims of this study were to compare disk diffusion with E-test method for levofloxacin susceptibility testing of Helicobacter pylori and standardized breakpoints for disk diffusion as a stable and reliable method for determining qualitative levofloxacin susceptibility. Materials and Methods:  We determined the levofloxacin susceptibility of 45 H. pylori strains isolated from Chinese patients by the E-test method. Disk diffusion was evaluated as an alternative method

to determine susceptibility and compared with the E-test results by linear regression analysis. Results:  The minimum inhibitory concentration (MIC) values tested by E-test method ranged from 0.047 to 32 μg/mL. Resistance to levofloxacin was detected in 16 (35.6%) isolates. The levofloxacin disk zone sizes obtained by disk diffusion method correlated well (r2 = .877) with the MICs obtained by E-test method. As a consequence of regression analysis, isolates with inhibition diameters <12 mm were considered resistant to levofloxacin. There was 100% agreement between the two methods for levofloxacin, applying the regression-based breakpoints. Conclusions:  The disk diffusion method is equivalent to the E-test method for testing levofloxacin susceptibility of H.

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