Figure 2.

(A) N-acyl homoserine lactone (AHL) activities of A. baumannii isolates collected in this study. Threshold for AHL production is shown in the graph. NC = negative control. Intensity of color was measured at OD520_nm.The results are mean of 3 simultaneous experiments. A P ≤ 0.05 was considered as statistically significant for 2-tailed tests. (B) Effect of iron-III concentrations on AHL activity in A. baumannii. Error bars represent the standard errors of the means for a representative assay performed in triplicate. X axis indicates A. baumannii isolates that showed a high and low AHL. (C) FT – IR spectra of AHL produced by A. baumannii isolates. The AHL was extract from organism by LLE- methods as described in the text. The pure compound was then subjected to FT-IR spectroscopy. The lactone ring and amide group were shown at 1764.69cm⁻¹ and 1659.23cm⁻¹ wave number. (D) Detection of LuxI (370 bp) and LuxR (603 bp) quorum sensing genes in A. baumannii isolates by multiplex-PCR. Electrophoresis was carried out in 1% agarose gel for 2 h at 80 V, the gel was stained with tracking dye (Syber green).