Table 2. Etest assessments of cell envelope integrity.

	FA1090 background			WHO X background
	WTa	ΔmlaAa	ΔmlaA/Plac::pldAa	WTa	ΔmlaAa
Polymyxin B	64	32	16	128	8
Vancomycin	8	4	4	16	8
Ceftriaxoneb	N/D	N/D	N/D	1.0d	1.0
Cefiximeb	N/D	N/D	N/D	2.0d	2.0
Azithromycin	0.064	0.064	1.0c	N/D	N/D
Cefotaxime	0.004	0.004	0.004	N/D	N/D
Ampicillin	0.125	0.064	0.125	N/D	N/D
Tetracycline	0.125	0.125	0.125	N/D	N/D
Benzylpenicillin	0.064	0.064	0.064	N/D	N/D
Gentamicin	4	4	4	N/D	N/D
Tobramycin	8	8	8	N/D	N/D
Ceftazidime	0.032	0.032	0.032	N/D	N/D

^aMIC values are presented in μg/mL.

^bPreliminary testing indicated FA1090 was too sensitive to this antibiotic for the MIC to be evaluated with Etests.

^cVector for PldA overexpression encodes erythromycin resistance, which also provides resistance against azithromycin.

^dPrior MIC determination performed on solid medium supplemented with hemoglobin and IsoVitalex [26]. N/D, not determined.