Table 4. Lipid A composition with genetic pmrB and other gene mutations of colistin-resistant Acinetobacter baumannii.

Relative percentage of each lipid A component peak (%)*	Genetic mutation not detected (N = 21)	Genetic mutation detected (N = 15)	P	pmrB gene single mutation (N = 7)	pmrB gene two mutations (N = 2)	pmrB gene and other mutation (N = 6)	P
Hexa	24.8 (18.9–37.4)	11.3 (8.7–14.7)	< 0.001	15.8 (10.8–19.2)	11.9 (10.3–13.5)	8.7 (2.0–11.3)	0.099
Hexa+1-PE	25.2 (20.0–32.8)	19.2 (17.0–22.4)	0.026	19.2 (17.4–22.0)	14.7 (10.6–18.9)	20.8 (16.7–23.5)	0.588
Hexa+2-PE	0.0 (0.0–1.1)	3.6 (1.1–5.6)	0.002	5.0 (3.0–6.4)	4.1 (0.7–7.4)	0.7 (0.0–3.6)	0.074
Hepta	21 (100.0%)	15 (100.0%)	-	7 (100.0%)	2 (100.0%)	6 (100.0%)	0.247
Hepta+1-PE	107.1 (84.6–127.7)	175.9 (138.1–196.4)	< 0.001	175.9 (140.8–179.9)	131.6 (118.5–144.7)	196.4 (136.8–219.5)	0.381
Hepta+2-PE	1.8 (0.6–4.1)	31.6 (25.2–36.9)	< 0.001	31.4 (29.4–34.8)	27.1 (22.0–32.2)	33.9 (11.4–42.6)	0.944
Octa	5.6 (0.0–10.0)	6.0 (3.2–7.5)	0.686	6.0 (5.1–6.7)	3.4 (1.6–5.1)	7.5 (0.0–8.2)	0.479
Octa+1-PE	71.3 (44.6–85.4)	42.8 (31.8–70.1)	0.127	51.5 ± 29.4	19.9 ± 4.5	65.0 ± 27.4	0.458
Octa+2-PE	5.8 (3.0–13.9)	85.3 (44.0–129.3)	< 0.001	55.3 (44.0–105.3)	34.7 (31.0–38.4)	125.8 (90.1–181.2)	0.029
Octa+2-PE+4C-H2O	0.0 (0.0–0.0)	23.9 (15.8–52.6)	< 0.001	21.1 (4.4–46.4)	15.8 (15.3–16.2)	45.5 (32.1–58.2)	0.201

Data are presented as number (%), mean±SD for parametric variables or median [1st quartile–3rd quartile] for non-parametric variables. Bold values are statistically significant (P<0.05)

^*Data represent the relative intensity (%) and their range compared with hepta-acylated lipid A, set as 100%.

Abbreviations: Hexa, hexa-acylated lipid A; Hepta, hepta-acylated lipid A; Octa, octa-acylated lipid A; PE, phosphoethanolamine; C, carbon.