Table 2. Prevalence of Staphylococcus aureus nasal carriage, US beefpacking workers (n = 137).

Characteristic	Prevalence % (n)	Prevalence ratio for S. aureusb	Multidrug resistant S. aureus % (n)c	PVL-positive % (n)d
Staphylococcus aureus (all)	27.0 (37/137)	-	10.2 (14/137) of all subjects; 38.9 (14/37) of S. aureus carriers	2.9 (4/137)
Methicillin-sensitive S. aureus (MSSA)	23.3 (32/137)	86.5	28.1 (9/32)	0 (0/5)
Methicillin-resistant S. aureus (MRSA)	3.6 (5/137)	13.5	100 (5/5)	80.0 (4/5)
Putative livestock-associated S. aureus (pLA-SA)a	3.6 (5/137)	13.5	40.0 (2/5)	0 (0/5)

^a Defined as all scn-negative S. aureus; all pLA-SA isolates were MSSA

^b Prevalence ratio defined as: # S. aureus isolates in specific category/all S. aureus positive isolates (n = 37)

^c Defined as resistant to ≥3 antibiotics tested

^d Positive for the lukS-PV and lukF-PV genes by real-time PCR