I Did Not Realise That!: Top Eleven UMI-77 Of This Era
The MICs of all peptides used in this study were determined against A.?baumannii strains with the microdilution method, following the CLSI recommendations [21]. The concentrations of the peptides mastoparan, indolicidin, colistin sulphate, histatin?5, cecropin?B, cecropin?A, magainin?II, buforin?I, magainin?I, histatin?8, bactenicin and melittin Nintedanib in vitro ranged from 256 to 0.5?mg/L. The concentrations of HNP-1 and HNP-2 ranged from 50 to 0.09?mg/L, and those for cecropin?P1 and ��-defensin ranged from 25 to 0.05?mg/L. The peptides used in this experiment (Table?1) were obtained from Sigma-Aldrich (St Louis, MO, USA), except for buforin?I (Anaspec, San Jose, CA, USA) and bactenicin (Genscript, Piscataway, NJ, USA). The peptides were dissolved in water, and the concentration used for the MICs was 1024?mg/L, except for HNP-1, HNP-2 (200?mg/L), cecropin?P1 and ��-defensin (102.4?mg/L). All peptide solutions were stored at ?20?C. Time-killing curves were obtained with mastoparan, the peptide presenting the best activity against colistin-susceptible and colistin-resistant A.?baumannii ATCC strains. Initial inocula between 1?��?106 and 5?��?106?CFU/mL of A.?baumannii in 10-mL aliquots of Mueller�CHinton broth were prepared for the time-killing curves. Concentrations of MIC?��1-fold, MIC?��2, MIC?��4 and MIC?��8 were used for mastoparan. Samples were taken at 0, 4, 7 and 24?h after incubation. Drug carryover was addressed by dilution. An antibiotic is considered to be bactericidal when a reduction of 3?log10?CFU/mL as compared with the initial inoculum is achieved UMI-77 [22]. These experiments were performed CYTH4 in duplicate. Fifteen different AMPs were tested against colistin-susceptible and colistin-resistant A.?baumannii. The MICs are shown in Table?2. Mastoparan and melittin showed the lowest MIC, at 4?mg/L each for colistin-susceptible A.?baumannii, and 1 and 2?mg/L for colistin-resistant A.?baumannii, respectively. Indolicidin showed MICs of 8 and 16?mg/L for colistin-susceptible A.?baumannii and colistin-resistant A.?baumannii, respectively. HNP-1 (3.25?mg/L) showed good activity against colistin-resistant A.?baumannii. However, the MIC for colistin-susceptible A.?baumannii was 50?mg/L. The other AMPs showed higher MICs (>25?mg/L) for both colistin-susceptible and colistin-resistant A.?baumannii. The MIC50 and MIC90 of mastoparan and indolicidin as compared with colistin were determined for 14 colistin-susceptible A.?baumannii clinical isolates that were epidemiologically unrelated, and the results are shown in Table?3. The results showed lower MICs for mastoparan (MIC50?4?mg/L) than for indolicidin (MIC50?16?mg/L), but their MICs were higher than colistin for colistin-susceptible A.?baumannii (MIC50?
