Myrtenol Inhibits Biofilm Formation and Virulence in the Drug-Resistant Acinetobacter baumannii: Insights into the Molecular Mechanisms

Figures & data

Table 1 List of Primers Used for qPCR Analysis

Genes	Forward Primer	Reverse Primer
bfmR	5′-CTGGTAGGTAATGCAGTTCG-3′	5′-GAGAGACCCAAACCATAACC-3′
rplB	5′-GGTCGTAATAACAACGGTCA-3′	5′-AATAATGCAATATGCGCTGT-3′
pgaC	5′-CAGTGGTATGGCGTGATATT-3′	5′-GGTACTGCAACAACACTGGT-3′
katE	5′-GTGTCCGGTTCAGGTTTTAC-3′	5′-GGATTCTTGACAGACCCAAC-3′
bap	5′-GTACTCCAGCAACGGTTGTA-3′	5′-GAAGGATCTGCTGTATTCCA-3′
csuA/B	5′-ATGCGGTAAATACTCAAGCA-3′	5′-TCACAGAAATATTGCCACCT-3′
ompA	5′-CTCTTGCTGGCTTAAACGTA-3′	5′-GCAATTTCTGGCTTGTATTG-3′
pgaA	5′-CACATGGCAAAAAGATGAAT-3′	5′-CGTAGAAACCTCGAACAGTG-3′

Figure 1 Growth and biofilm formation of BP-AB assessed by curve analysis.

Figure 2 Inhibitory curve with various concentrations of myrtenol treatment on biofilm formation of BP-AB.

Figure 3 Antibiofilm efficacy comparison with various concentrations of myrtenol treatment on biofilm formation of BP-AB.

Note: ****Represents P<0.01.

Figure 4 (A)Effect of various concentrations of myrtenol treatment on BP-AB biofilm formation on glass test tubes. (B) Microscopic images representing the antibiofilm efficacy with various concentrations of myrtenol treatment against BP-AB. (C) CLSM images representing the antibiofilm efficacy with various concentrations of myrtenol treatment against BP-AB. (D) SEM images representing the antibiofilm efficacy with various concentrations of myrtenol treatment against BP-AB.

Figure 5 Comstat analysis of biofilms formed by BP-AB strains with various concentrations of myrtenol treatment.

Note: *Represents P<0.001.

Figure 6 Effect of various concentrations of myrtenol treatment on expression profile of genes involved in biofilm formation in BP-AB.

Note: *Represents P<0.01.

Figure 7 A schematic diagram representing the effect of myrtenol treatment on biofilm associated genes expression in BP-AB.

Table 2 Antibiotic MIC Values of blaNDM-1-Producing Acinetobacter Baumannii Strains in the Absence and Presence of Myrtenol

Antibiotics	MIC(μg/mL)
	WT	50μg/mL	100μg/mL	200μg/mL	250μg/mL	300μg/mL
Piperacillin/Tazobactam	164/6	160/6	158/6	146/4*	142/4*	140/4*
Cefoperazone/Sulbactam	146/6	144/6	140/6	112/4*	110/4*	108/4*
Meropenem	18	16	18	14	16	14
Ceftazidime	64	64	64	38*	36*	32*
Amikacin	82	78	76	68*	66*	66*

Notes: Breakpoint Interpretation:Amikacin S≤16μg/mL, I=32μg/mL, R≥64μg/mL, Meropenem S≤2μg/mL, I=4μg/mL, R≥8μg/mL, Piperacillin/Tazobactam S≤16/4μg/mL, I=32/4μg/mL, R≥128/4μg/mL, Cefoperazone/Sulbactam S≤16/4μg/mL, I=32/4μg/mL, R≥128/4μg/mL, Ceftazidime S≤8μg/mL, I=16μg/mL, R≥32μg/mL. *Represents p<0.05 of comparison with WT group.

Abbreviations: S, susceptible; I, intermediate; R, resistant.