Table 1.

AMP resistance mechanisms examined in vivo

Mechanism of AMP Resistance	Organism	Virulence Factor(s)	In vivo Model(s), route of inoculationa	Reference(s)
Electrostatic Repulsion
PEA modification of lipid A	N. gonorrhoeae	LptA	Human, male, intraurethral	[15]
			Mouse, female, intravaginal	[15, 30]
	S. Typhimurium	PmrC	Mouse, oral and i.p.	[35]
PEA modification of LOS core	S. Typhimurium	CptA	Mouse, oral and i.p.	[35]
PEA modification of LPS, flagella, glycans	C. jejuni	EptC	Mouse, oral Chick, oral	[34] [34]
Aminoarabinose modification of LPS	S. Typhimurium	PmrHFIJKLM	Mouse, oral and i.p.	[17, 18]
			Mouse, CRAMP−/−, oral	[18]
			Mouse, MMP7−/−, oral	[18]
D-Ala modification of lipoteichoic acid	Group B Streptococcus	DltA	Rat, i.p. Mouse, i.n. and i.v.	[42] [42]
	L. monocytogenes	DltA	Mouse, i.v.	[45]
	S. aureus	DltA	Mouse, i.v.	[41]
			Rabbit, i.v.	[44]
L-Lys modification of cell membrane phosphatidylglycerol	S. aureus	MprF	Rabbit, i.v.	[44]
			Mouse, i.v.	[43]
	L. monocytogenes	MprF	Mouse, i.v.	[46]
Galactosamine modification of lipid A	F. novicida	AlmEFG	Mouse, subcutaneous	[37]
Membrane fluidity/permeability
Lipid A modified by acylation	K. pneumoniae	LpxM	Mouse, i.n. and i.v.	[48]
	L. pneumophila	Rcp	Mouse, i.t.	[47]
LPS truncation
LPS core synthesis	P. multocida	HptA	Chicken, i.m.	[50]
	H. influenzae, nontypeable	LpsA, OpsX, LgtF	Mouse, i.n.	[51]
	B. cenocepacia	HldA, HldD	Rat, i.t.	[49]
	B. bronchiseptica	Pgm	Mouse, i.n.	[52]
Surface modification
LPS biosynthesis	S. Typhimurium	Pgm	Mouse, i.v.	[53]
modification of unidentified surface structures	Y. pestis	PgmA	Mouse, i.n. and i.v.	[25]
Phosphate modification of LPS core	S. Typhimurium	WaaP	Mouse, oral, i.p., and i.v.	[54]
Phosphocholine modification of LPS core	P. multocida	PcgC	Chicken, i.m. and i.t.	[55]
Transport
Efflux Pump	N. gonorrhoeae	MTR	Mouse, female, intravaginal	[62, 64]
	V. cholerae	VexAB	Mouse, infant, oral	[65]
Uptake transport	E. chrysanthemi	SapABCDF	Potato tuber, injection	[77]
			Chicory leaves, injection	[82]
	H. ducreyi	SapA	Human, cutaneous	[13]
		SapBC	Human, cutaneous	[79]
	H. influenzae, nontypeable	SapA	Chinchilla otitis	[72, 75]
		SapD	Chinchilla otitis	[78]
	S. Typhimurium	SapCDF, SapDF	Mouse, oral and i.p.	[73]
		YejABDF	Mouse, oral and i.p.	[90]
AMP binding proteins
Bind AMP, prevent AMP from reaching cell membrane	Group B Streptococcus	PilB	Mouse, i.p. and i.v.	[89]
	Group A Streptococcus	SIC	Mouse, i.p.	[91]
Unclear
Ferrous iron-binding protein	S. Typhimurium	Omb	Mouse, oral and i.p.	[92]

^aRoutes of inoculation: i.m., intramuscular; i.n., intranasal; i.p., intraperitoneal; i.t., intratracheal; i.v., intravenous