Table 2.

Modulation of AMR by microbial volatile compounds (MVCs).

MVCs	Origin Microorganism	Target Microorganism	Antimicrobial Resistance	Mechanism	References
Trimethylamine	E. coli	E. coli, P. aeruginosa, S. aureus, and B. subtilis	Tetracycline	Increasing the transmembrane pH and lowering the transport of tetracycline inside the cell	[39]
Ammonia (NH3)	E. coli	E. coli	Tetracycline	Promoting intracellular accumulation of polyamines by modifying membrane permeability	[40]
Indole	E. coli	Pseudomonas putida	ampicillin	Inducing the Pseudomonas TtgGHI antibiotic efflux pump	[41]
2,3-Butanedione and glyoxylic acid	B. subtilis	E. coli	Ampicillin and tetracycline	The induction of the expression of hipA and hipB, TA system related genes, resulting in bacterial persistence	[42]
2-Aminoacetophenone	P. aeruginosa	Acinetobacter baumanii	Meropenem and tetracycline	Stimulating persisters formation	[43]
Hydrogen sulfide (H2S)	Bacillus anthracis, P. aeruginosa, S. aureus, and E. coli	B. anthracis, P. aeruginosa, S. aureus, and E. coli	A range of different antibiotics targeting DNA, RNA, cell wall, or protein biosynthesis	Mitigation of oxidative stress imposed by antibiotics	[44]
Dimethyl trisulfide, 1-methylthio-3-pentanone and o-aminoacetophenone	Burkholderia ambifaria	E. coli	Aminoglycosides, such as gentamicin and kanamycin	Unknown	[45]
Nitric oxide (NO)	Many Gram-positive bacteria, such as B.subtilis and S. aureus	NO producing and non-producing microorganisms	A broad spectrum of antibiotics such as cefuroxime	Chemical modification of toxic compounds and the alleviation of the oxidative stress	[46]