Table 4.

Number (%) of MRSA isolates recovered from wastewater by SCCmec type and by possession of the pvl gene.

Sampling location	SCCmec typea			PVL-positiveb
	Type II	Type IV	No mecA
Mid-Atlantic WWTP1 (n = 100)
Influent (n = 40)	0 (0)	40 (100)	0 (0)	28 (70)
Activated sludge reactor (n = 40)	13 (33)	27 (68)	0 (0)	25 (63)
Secondary clarifier (n = 20)	0 (0)	19 (95)	1 (5)	18 (95)
Effluent (n = 0)	0 (0)	0 (0)	0 (0)	0 (0)
Total (n = 100)	13 (13)	86 (86)	1 (1)	71 (72)
Mid-Atlantic WWTP2 (n = 47)
Influent (n = 20)	0 (0)	20 (100)	0 (0)	9 (45)
Activated sludge reactor (n = 27)	0 (0)	27 (100)	0 (0)	26 (96)
Secondary clarifier (n = 0)	0 (0)	0 (0)	0 (0)	0 (0)
Effluent (n = 0)	0 (0)	0 (0)	0 (0)	0 (0)
Total (n = 47)	0 (0)	47 (100)	0 (0)	35 (75)
Midwest WWTP1 (n = 69)
Influent (n = 22)	0 (0)	19 (86)	3 (14)	9 (47)
Post aeration (n = 21)	0 (0)	21 (100)	0 (0)	20 (95)
Secondary clarifier (n = 13)	0 (0)	13 (100)	0 (0)	13 (100)
Effluent (n = 13)	0 (0)	13 (100)	0 (0)	13 (100)
Total (n = 69)	0 (0)	66 (96)	3 (4)	55 (83)
Midwest WWTP2 (n = 24)
Influent (n = 24 )	24 (100)	0 (0)	0 (0)	0 (0)
Cell B (n = 0)	0 (0)	0 (0)	0 (0)	0 (0)
Effluent (n = 0)	0 (0)	0 (0)	0 (0)	0 (0)
Total (n = 24)	24 (100)	0 (0)	0 (0)	0 (0)
aSCCmec types I, III, V, and VI were not identified in any sample. bPVL PCR was performed only on isolates with the mecA gene.