Comparison of Clinical Characteristics and Outcomes Between Positive and Negative Blood Culture Septic Patients: A Retrospective Cohort Study

Figures & data

Table 1 Characteristics of the Study Cohort

	Culture-Positive(n=274)	Culture-Negative(n=318)	P-value
Demographic
Sex (Male%)	175(63.9%)	203(63.8%)	0.531
Age, years≥65(%)	170(62.0%)	137(43.1%)	0.039*
Age, median	66(54.75, 75.75)	61(57.25, 70.00)	0.155
Nursing home residents (%)	19 (6.9%)	15 (4.7%)	0.248
Comorbidities
COPD%	126 (46.0%)	121(38.1%)	0.051
Hypertension, %	142 (51.8%)	137(43.1%)	0.034*
CVD, %	57 (20.1%)	83 (26.1%)	0.131
CHF, %	75 (27.4%)	41 (12.9%)	<0.001*
CRD, %	37 (13.5%)	47 (14.8%)	0.657
DM, %	187(68.2%)	162 (50.9%)	<0.001*
Tumor, %	43 (15.7%)	32 (10.1%)	0.040*
Site of primary infection
Low respiratory tract infection	161 (58.8%)	146 (45.9%)	0.002*
Urinary tract infection	63 (23.0%)	47(14.8%)	0.010*
Intra-abdomen infection	21 (7.7%)	23 (7.2%)	0.842
Skin and soft tissue infection	9 (3.2%)	8(2.5%)	0.576
Others	3(1.1%)	4(1.3%)	0.855

Note: *P<0.05.

Abbreviations: COPD, chronic obstructive pulmonary disease; CVD, cerebrovascular disease; CHF, congestive heart failure; CRD, chronic renal disease; DM, diabetes mellitus.

Figure 1 Flowchart of the study population.

Figure 2 The primary infection sites of culture-positive and culture-negative groups. *P<0.05, **P<0.01.

Table 2 Comparison of Laboratory Characteristic and Severity Between Culture Positive and Culture Negative Patients

	Culture-Positive(n=274)	Culture-Negative(n=318)	P-value
Vital signs
Temperature>38°C(%)	257 (93.8%)	296 (93.1%)	0.876
MBP(mmHg)	83 (65, 92)	110 (98, 120)	<0.001*
Heart rate(bpm)	108 (95, 110)	83 (72, 96)	<0.001*
Respiratory rate(bpm)	36 (32, 37)	30 (29, 31)	<0.001*
Laboratory examination
WBC, 10^^9/L	13.7 (12.8, 14.9)	10.5 (9.6, 11.4)	<0.001*
Platelet, 10^^9/L	120 (112, 130)	120 (100, 137)	0.851
ALB, g/L	19 (17, 22)	22 (19, 24)	0.008*
CRP, mg/L	100 (89, 115)	98 (80, 110)	0.080
PCT, pg/mL	1.2 (0.7, 3.34)	1.0 (0.5, 1.76)	0.008*
Lac, mmol/L	1.9 (1.4, 2.2)	1.6 (1.2, 1.9)	0.104
Severe score
SOFA	4 (2, 4)	2 (1, 2)	<0.001*
MEDS	11 (8, 12)	7 (5, 8)	<0.001*
APACHE II	15 (11, 19)	11(8, 13)	0.010*
PIRO	17(14, 19)	11(10, 14)	<0.001*

Note: *P<0.05.

Abbreviations: MBP, mean blood pressure; WBC, white blood cell; ALB, albumin; CRP, C-reactive protein; PCT, procalcitonin; Lac, lactate; SOFA, Sequential Organ Failure Assessment; MEDS, Mortality in Emergency Department Sepsis; APACHE II, Acute Physiology and Chronic Health Evaluation II; PIRO, Predisposition, Infection, Response, and Organ dysfunction.

Table 3 Frequency of Bacteria for the Positive Blood Culture Sepsis in the Throughout Hospital

Bacteria (n=274)	Frequency (%)	Total Mortality (%)(n=69)	Net Mortality (%)
Gram-negative bacteria
Escherichia coli	46 (16.8%)	14 (20.3%)	30.4%
Klebsiella pneumoniae	35 (12.8%)	18(26.1%)	51.4%
Pseudomonas aeruginosa	9 (3.3%)	4 (5.8%)	44.4%
Acinetobacter baumannii	7 (2.6%)	3 (4.3%)	42.9%
Enterobacter cloacae	7 (2.6%)	0	0
Brucella mevis	5 (1.8%)	0	0
Streptococcus pneumoniae	2 (0.7%)	0	0
Enterobacter aerogenes	2 (0.7%)	0	0
Others	34(12.4%)	0	0
Gram-positive bacteria
Enterococcus faecium	24(8.8%)	6(8.7%)	25.0%
Staphylococcus epidermidis	22(8.0%)	4(5.8%)	18.2%
Staphylococcus hominis	20 (7.3%)	7(10.1%)	35.0%
Staphylococcus aureus	15 (5.5%)	11(15.9%)	73.3%
Staphylococcus capitis	12 (4.4%)	1(1.4%)	8.3%
Staphylococcus wokeri	4 (1.5%)	1(1.4%)	8.3%
Staphylococcus haemolyticus	2 (0.7%)	0	0
Enterococcus aerogenes	2 (0.7%)	0	0
Others	26(9.5%)	0	0

Table 4 Frequency of Bacteria for the Positive Blood Culture Sepsis in the ICU

Bacteria (n=81)	Frequency (%)	Total Mortality (%)(n=37)	Net Mortality (%)
Gram-negative bacteria
Klebsiella pneumoniae	9 (11.1%)	8 (21.6%)	88.9%
Acinetobacter baumannii	7 (8.6%)	6 (16.2%)	85.7%
Escherichia coli	6 (7.4%)	4 (10.8%)	66.7%
Pseudomonas aeruginosa	4 (4.9%)	3 (8.1%)	75.0%
Proteus	2 (2.5%)	0	0
Enterobacter aerogenes	1 (1.2%)	0	0
Others	6 (7.4%)	0	0
Gram-positive bacteria
Staphylococcus hominis	10(12.3%)	4(10.8%)	40.0%
Enterococcus faecium	8 (9.9%)	2 (5.4%)	25.0%
Staphylococcus epidermidis	7 (8.6%)	3 (8.1%)	42.9%
Staphylococcus capitis	5(6.2%)	4 (10.8%)	80.0%
Staphylococcus aureus	4 (4.9%)	3(10.1%)	75.0%
Staphylococcus wokeri	2 (2.5%)	0	0
Staphylococcus haemolyticus	1 (1.2%)	0	0
Staphylococcus acidogenes	1 (1.2%)	0	0
Staphylococcus longum	1 (1.2%)	0	0
Others	7 (8.6%)	0	0

Table 5 Frequency of Bacteria for the Positive Blood Culture Sepsis in the ED

Bacteria (n=93)	Frequency (%)	Total Mortality (%)(n=23)	Net Mortality (%)
Gram-negative bacteria
Klebsiella pneumoniae	11 (11.8%)	8 (34.8%)	72.7%
Escherichia coli	11(11.8%)	5 (21.7%)	45.5%
Acinetobacter baumannii	4 (4.3%)	3 (13.0%)	75.0%
Others	5 (5.4%)	0	0
Gram-positive bacteria
Staphylococcus epidermidis	18 (19.4%)	1(4.3%)	5.6%
Staphylococcus hominis	13 (14.0%)	1 (4.3%)	7.7%
Enterococcus faecium	7 (7.5%)	1 (4.3%)	14.3%
Staphylococcus aureus	6 (6.5%)	4 (17.4%)	66.7%
Staphylococcus capitis	5 (5.4%)	0	0
Staphylococcus longum	2 (2.2%)	0	0
Staphylococcus haemolyticus	1(1.1%)	0	0
Streptococcus pneumoniae	1 (1.1%)	0	0
Others	9 (9.7%)	0	0

Figure 3 The distribution and total mortality of all kinds of bacteria in the throughout hospital among culture-positive bacteria. (A) The distribution of all kinds of bacteria in the throughout hospital among culture-positive bacteria. (B) The total mortality of all kinds of bacteria in the throughout hospital among culture-positive bacteria.

Figure 4 The distribution and total mortality of all kinds of bacteria in the ICU among culture-positive bacteria. (A) The distribution of all kinds of bacteria in the ICU among culture-positive bacteria. (B) The total mortality of all kinds of bacteria in the ICU among culture-positive bacteria.

Figure 5 The distribution and total mortality of all kinds of bacteria in the ED among culture-positive bacteria. (A) The distribution of all kinds of bacteria in the ED among culture-positive bacteria. (B) The total mortality of all kinds of bacteria in the ED among culture-positive bacteria.

Table 6 Comparison of Outcomes Between Positive and Negative Blood Culture Sepsis

	Culture-Positive (n=274)	Culture-Negative (n=318)	P-value
ICU admission (%)	81(29.6%)	66(20.8%)	0.013*
ICU stay(days)	14(11, 22)	6 (4, 9)	<0.001*
With ARDS (%)	123(44.9%)	111(34.9%)	0.013*
Non-invasive ventilator (days)	3 (2, 4)	2 (2, 4)	0.786
Invasive ventilator (days)	9 (6, 13)	4(3, 7)	0.018*
ICU Cost (RMB)	39,000(28,000, 63,000)	24,000(20,000, 38,000)	0.125
ICU mortality (%)	37(45.7%)	24(36.4%)	0.254
In-hospital mortality (%)	40(14.6%)	27(8.5%)	0.019*
Early (28-day) mortality (%)	26(9.5%)	23(7.2%)	0.321
Late (28–90 day) mortality (%)	43(15.7%)	22(6.9%)	0.001*
Total mortality (%)	69 (25.2%)	45(14.2%)	0.001*
Culture-Positive Appropriate antibiotics mortality (%)	20 (7.3%)
Culture-Positive Inappropriate antibiotics mortality (%)	49(17.9%)

Note: *P<0.05.

Abbreviations: ICU, Intensive Care Unit; ARDS, acute respiratory distress syndrome.

Figure 6 The mortality of ICU, in-hospital, early day (28-day) and late day (28–90-day) between culture-positive and culture-negative groups. *P<0.05, **P<0.01.

Figure 7 The Kaplan-Meier survival curve facilitated visual comparison between culture-positive and culture-negative septic patients. The results showed that the two groups had comparable early mortality but worse late mortality (Log-rank P value=0.001). *P<0.05.

Figure 8 Odds ratio for culture-positive group and culture-negative group. (A) Odds ratio for culture-positive group. (B) Odds ratio for culture- negative group.

Figure 9 The clinical outcomes and mortality of culture-positive patients after receiving appropriate antibiotic. **P<0.01, ***P<0.001.