TABLE 2.

Risk factors for and outcomes associated with time to positivity (≤12 or >12 h) in S. aureus BSIs

Variable	Time to positivity ≤12 h (n = 44)		Time to positivity >12 h (n = 47)		P
	No. of patients	% of patients	No. of patients	% of patients
Demographic characteristicsa					0.027
Female	24	54.5	30	63.8	0.078
ICU stay	4	9.1	7	14.9	0.52
Underlying conditions
Charlson score ≥3	23	52.3	14	29.8	0.029
Rapidly fatal disease (MacCabe classification)	8	18.2	3	6.4	0.11
End-stage renal disease	9	20.5	7	14.9	0.59
Diabetes	16	36.4	14	29.8	0.50
Neoplasia	7	15.9	3	6.4	0.19
Neutropenia	5	11.4	0		0.023
Endocarditis	11	25.0	4	8.5	0.048
Conditions related to the clinical course
Maximal inflammatory response	9	20.5	7	14.9	0.59
APACHE II score ≥20 at BSI onset	15	34.1	5	10.6	0.010
Hospital-acquired bacteremia	14	31.8	19	40.4	0.39
Methicillin-resistant S. aureus	22	50.0	20	42.6	0.48
Adequate antibiotic therapy	35	79.5	29	61.7	0.063
Source of infection
Intravascular catheter	17	38.6	7	14.9	0.010
Respiratory tract	1	2.3	5	10.6	0.20
Urinary tract	0	0.0	2	4.3	0.49
Skin and soft tissue	5	11.4	7	14.9	0.76
Bone and joint	4	9.1	3	6.4	0.71
Gastrointestinal	0	0.0	3	6.4	0.24
Wound	2	4.5	3	6.4	1.0
Other	5	11.4	5	10.6	1.0
Unknown	10	22.7	13	27.7	0.59
Outcomes
Organ failure	16	36.4	15	31.9	0.66
Septic shock	6	13.6	4	8.5	0.51
Respiratory failure	7	15.9	10	21.3	0.60
Renal failure	3	6.8	6	12.8	0.49
Hematologic failure	7	15.9	1	2.1	0.027
Hepatic failure	3	6.8	5	10.6	0.72
In-hospital mortality	11	25.0	2	4.3	0.006

^aThe mean ages of the patients in the groups with TTPs of ≤12 h and >12 h were 53.5 ± 14.9 and 46.3 ± 15.5 years, respectively.