Table 2. Mutations altering giant cell formation.

The genes with the strongest mutant phenotypes among the deletion mutants examined (S1 Table) are listed. The number/total Tn-seq runs in which mutants in the indicated genes were significantly depleted or enriched are indicated. PBP, penicillin binding protein; nd, not determined due to low representation in the ΔPBP2 transposon mutant pooled library; wt, wild type.

Locus	Gene	Product	Fosfomycin (wt)		Aztreonam (ΔPBP2)
			Tn-seq recovery	Deletion phenotype	Tn-seq recovery	Deletion phenotype
ACIAD0527	gcf	Sel1 domain	Decreased (2/2)	Fails to form giant cells, early lysis	nd	Early lysing clusters of small giant cells
ACIAD0551	nagZ	N-acetyl-ß-glucosaminidase	Decreased (2/2)	Early forming, early lysing giant cells	Decreased (7/8)	Slightly early lysing giant cells
ACIAD1138	mltD	Lytic transglycosylase	Decreased (2/2)	Fails to form giant cells, early lysis	–	Early lysing small giant cells
ACIAD1225	dacA	PBP5	–	Forms giant cells	Decreased (8/8)	Early forming, early lysing giant cells
ACIAD1396	–	Histidine triad protein	Increased (2/2)	Late forming, late lysing giant cells	Increased (8/8)	Partial resistance
ACIAD2234	mrcB	PBP1b	Decreased (2/2)	Fails to form giant cells, early lysis	Decreased (2/8)	Early forming, early lysing giant cells
ACIAD2235	lpoB	PBP1b activator	Decreased (2/2)	Fails to form giant cells, early lysis	Decreased (1/8)	Forms giant cells
ACIAD2336	zapE	Divisome ATPase	Increased (2/2)	Late forming, late lysing giant cells	Increased (8/8)	Partial resistance
ACIAD2475	ldtG	L, D-transpeptidase	–	Forms giant cells	Decreased (8/8)	Early forming, early lysing giant cells
ACIAD3361	ponA	PBP1a	–	Forms giant cells	Decreased (7/8)	Early forming, early lysing giant cells
ACIAD3380	ettA	Translation regulator	Increased (2/2)	Late forming stable giant cells	Increased (5/8)	Partial resistance