Figure 2 Stability of ϕAB2 under (A) temperature, (B) pH, (C) chloroform, and (D) glass surface. The dotted line indicates no plaque survival at the respective storage time. These experiments were repeated three times and the data shown are the mean ± SEM. Effect OSI-906 research buy of pH on ϕAB2 stability The optimal pH for ϕAB2 stability was determined (Figure 2B). ϕAB2 was relatively stable following

360-day incubation at pH 7. Under these conditions, there was a 2-log decrease in ϕAB2 phage titers from the initial titer of 108 PFU/ml. However, ϕAB2 titers decreased by over 5-logs after 180-day incubation at pH 4 or pH 11. In extremely acidic conditions, at pH 2, no ϕAB2 plaques were identified after 10 min (data not shown). Thus, ϕAB2 is unstable Pexidartinib under extreme pH conditions.

Effect of chloroform concentration on ϕAB2 stability ϕAB2 titers were reduced following exposure to chloroform concentrations of 0.5% and 2% (Figure 2C). For phage purification, a chloroform concentration of 0.5–2% (v/v) is typically used, thus the infectivity of ϕAB2 following exposure to 0.5% and 2% chloroform was investigated. ϕAB2 exposed to 0.5% chloroform retained stable infectivity of greater than 20% following a 360-day storage period. However, infectivity retention of ϕAB2 was only 5% following a 360-day storage period in 2% chloroform (Figure 2C). ϕAB2 stability on glass slides Desiccation reduced the stability of ϕAB2 when spiked onto a glass surface over a 65-day period (Figure 2D). There was a 1-log decrease in ϕAB2 titers (initial phage concentration of 108 PFU/slide) after 12 h on the glass surface. Infectivity of ϕAB2 on a glass slide was 0.1% after 7 days and 0.001% after 30 days. Thus, ϕAB2 could survive on a dried glass surface for 2 months, although a large reduction in ϕAB2 titers was observed. Reduction of MDRAB by ϕAB2 in a liquid suspension We next https://www.selleckchem.com/products/ch5183284-debio-1347.html assessed the ability of ϕAB2 to reduce the concentration of A. baumannii M3237 in sterile water over different incubation times (the duration of contact of the phages with the hosts). The addition 5-Fluoracil manufacturer of ϕAB2 to a liquid suspension of

A. baumannii M3237 had a strong bactericidal effect in all test groups except the 5 min incubation low dose group (103 PFU/ml) (Figure 3). The ϕAB2 bactericidal effect showed a dose-response as the lowest concentration of ϕAB2 tested (103 PFU/ml) exhibited the weakest bactericidal capability, which was 6,600-fold lower than when higher phage concentrations (105 and 108 PFU/ml) were used (Figure 3A). The addition of 105 or 108 PFU/ml ϕAB2 reduced the number of A. baumannii M3237 by at least 3-logs at all bacterial test concentrations after 5 min. After 10 min incubation, the effect was even greater, with at least a 4-log reduction in MDRAB survival rates (Figure 3B and C). In addition, the mean reduction in bacteria was greater when a higher initial bacterial concentration was used.