Table 1.
Acinetobacter baumannii strains used in the study.
Fig 1.
Opaque and translucent variants of A. baumannii clinical isolates.
(A) Stereo microscopic images of opaque and translucent colonies, and (B) Phase variation switching frequency of A. baumannii clinical isolates. In order to compare switching frequencies the unpaired paired t test was performed. The difference is considered as statistically significant if p values is less than 0.05 and represented by “*”.
Fig 2.
Scanning electron microscopic images of bacterial cells from opaque and translucent colonies of A. baumannii clinical isolates.
Scale bar = 200 nm, Magnification 100,000x.
Fig 3.
Biofilm formation capability of opaque and translucent colony variants.
Biofilm formation after 24 hours at (A), 37° C, and (B) 30° C. Bars represent Mean± SD of OD595 values. Difference in biofilm forming capability of opaque and translucent strains was estimated by two tail paired t test. The difference is considered as statistically significant if p values is less than 0.05. p value less than 0.05 is represented by“*”, p value less than 0.01 is represented by “**”. p value higher than 0.05 is represented by ns (non significant).
Fig 4.
Virulence associated features of A. baumannii opaque and translucent variants.
(A) Progeny count of C. elegans upon feeding with opaque and translucent variants of A. baumannii, E. coli OP50 and V. cholerae C6706luxOc, Bars represent Mean± SD of progeny counts. Difference in progeny count induced by opaque and translucent strains was estimated by two tail paired t test. The difference is considered as statistically significant if p values is less than 0.05. p value less than 0.05 is represented by“*”, p value less than 0.01 is represented by “**” and p value less than 0.001 is represented by “***”. p value higher than 0.05 is represented by ns (non significant). (B) NFKB nuclear translocation and activation in response to A. baumannii Ab-Pak-Pesh-37 opaque and translucent phase variants after 4 hours infection. Scale bar = 5μm, and (C) Quantification of NFKB staining intensity in cell nuclei (n = 20 cells). Groups were compared using paired t-test (Microsoft Excel). p values of <0.01 ** and <0.05 * were considered statisitically significant.
Fig 5.
Outer membrane vesicles released by A. baumannii opaque and translucent variants.
(A) Visualization of OMVs from opaque and translucent phase variants by atomic force microscopy, (B) Cellular uptake of micro vesicles (OMVs) isolated from A. baumannii Ab-Pak-Pesh-37 opaque (upper panel) and translucent (lower panel) phase variants. Scale bar = 5μm, (C) NFKB nuclear translocation and activation in response to OMVs isolated from A. baumannii Ab-Pak-Pesh-37. Scale bar = 5μm, and (D) Quantification of NFKB staining intensity in cell nuclei (n = 20 cells). Groups were compared using paired t-test (Microsoft Excel). Groups were compared using paired t-test (Microsoft Excel). p values of <0.01 ** or <0.05 * were considered statistically significant.