Table 2.

S. aureus infections by time period, clinical syndrome, demographics, and onset type, Kaiser Permanente of Northern California^a

Characteristics	Value
	Moderately increasing MRSA (1998–2001)		Rapidly increasing MRSA (2002–2005)		Moderately decreasing MRSA (2006–2009)
	No. of infections	% MRSA	No. of infections	% MRSA	No. of infections	% MRSA
Clinical syndromesb
Necrotizing fasciitis/toxic shock	37	27	78	37	103	49
Deep organ abscess	317	28	607	51	796	48
Skin and soft tissue infection	15,718	13	30,775	42	66,382	48
Pneumonia or lung related	2,023	33	3,169	51	3,003	50
Joint or bone infection	1,947	14	2,668	30	3,496	34
Urinary tract infection	2,548	30	4,094	49	4,561	48
Ear, nose, throat infections	1,695	5	1,929	18	2,884	25
Shock	307	34	794	51	982	50
Fever	749	18	1,252	34	1,332	35
Other selected syndromesc	446	27	626	45	687	42
Age (yr)
Under 5	1,251	5	2,014	32	5,461	46
5 to <18	2,108	5	4,088	34	10,980	41
18 to <50	6,584	8	13,406	44	28,526	50
50 to <65	4,824	13	7,958	37	14,847	44
65+	6,475	26	10,409	44	14,519	45
Race/ethnicity
Asian	1,645	10	2,982	29	6,204	35
African-American	1,852	19	3,639	54	7,210	60
Hispanic	2,602	12	5,137	41	11,912	48
Other or unknown race	2,803	10	5,799	43	12,268	48
White	12,340	15	20,318	40	36,739	45
Onset type
Health care associated, hospital onset	2,152	41	3,469	58	3,159	56
Health care associated, community onset	7,395	20	11,098	40	16,312	45
Community associated	11,695	6	23,308	39	54,862	46

^aInfections were defined as the first positive S. aureus isolate per patient per 365-day period and patients who were diagnosed with a potentially S. aureus-related clinical syndrome from 7 days before to 7 days after the index date. Only isolates from blood, bone, CSF, body fluid, urine, tissue, respiratory, and other miscellaneous bacterial specimens (such as those taken from abscesses, pustules, boils, and wounds) were included.

^bClinical syndromes were based on ICD9 codes received by the patient from 7 days before to 7 days after the S. aureus specimen was obtained. Patients could have more than one clinical syndrome, and thus, the numbers add up to more than the total number of infections.

^cIncludes meningitis, intracranial abscess, tracheostomy infection, esophagostomy infection, gastrostomy infection, nonhealing surgical wounds, acute pericarditis, acute endocarditis, acute myocarditis, other diseases of the pericardium, arterial embolism, and thrombosis.