Predictors of Carbapenem-Resistant Klebsiella pneumoniae Acquisition among Hospitalized Adults and Effect of Acquisition on Mortality

Mitchell J. Schwaber; Shiri Klarfeld-Lidji; Shiri Navon-Venezia; David Schwartz; Azita Leavitt; Yehuda Carmeli

doi:10.1128/AAC.01020-07

DOI: 10.1128/AAC.01020-07

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Tables

TABLE 1.
Sources of samples for culture^a
Source % of patients
CSKS CRKP
Unknown or other 0 6
Blood/intravenous line 15 13
Respiratory 9 8
Urine 55 40
Wound/skin/soft tissue 15 19
Abdomen 7 15
↵ a P = 0.58 by Kruskall-Wallis test.

TABLE 2.

Univariate predictors of Klebsiella sp. isolation

Covariate	No. (%) of patients^a			Time-adjusted comparison of patients with CRKP and controls		Time-adjusted comparison of patients with CSKS and controls
	Klebsiella cases		Controls (n = 59)	OR (95% CI)	P	OR (95% CI)	P
	Carbapenem resistant (n = 48)	Carbapenem susceptible (n = 56)	Controls (n = 59)	OR (95% CI)	P	OR (95% CI)	P
Male sex	23 (48)	18 (32)	24 (41)	0.9 (0.3-2.6)	0.86	0.7 (0.3-1.6)	0.38
Diabetes mellitus	15 (31)	15 (27)	18 (31)	1.1 (0.4-3.2)	0.87	0.9 (0.4-2.2)	0.87
Cardiovascular disease	29 (60)	35 (64)	64 (64)	1.3 (0.4-3.6)	0.68	0.9 (0.4-1.9)	0.72
Pulmonary disease	9 (19)	9 (16)	14 (24)	0.2 (0.1-1.1)	0.07	0.6 (0.2-1.5)	0.28
Renal disease	15 (31)	10 (18)	12 (20)	1.1 (0.4-3.6)	0.82	0.9 (0.4-2.4)	0.86
Liver disease	2 (4)	4 (7)	3 (5)	0.2 (0.02-3.0)	0.25	1.3 (0.3-6.4)	0.75
Neurologic disease	20 (42)	16 (29)	10 (17)	6.7 (2.1-21.4)	0.001	2.4 (1.0-6.0)	0.06
Malignancy	15 (31)	19 (35)	9 (15)	1.7 (0.5-5.7)	0.37	3.1 (1.3-7.9)	0.02
Immunosuppression	11 (23)	8 (15)	4 (7)	1.9 (0.4-8.0)	0.40	2.3 (0.6-8.2)	0.21
High no. of comorbidities	19 (40)	20 (36)	19 (32)	1.3 (0.4-3.5)	0.68	1.3 (0.6-3.0)	0.48
Admission from institution	15 (31)	9 (16)	6 (10)	9.9 (2.7-36.4)	<0.001	1.7 (0.5-5.4)	0.37
Transplantation	2 (4)	0 (0)	0 (0)
Poor functional status	29 (62)	23 (41)	8 (14)	14.3 (4.2-48.5)	<0.001	4.6 (1.8-11.8)	0.001
High Charlson comorbdity index score	19 (40)	23 (41)	11 (19)	3.0 (1.0-8.9)	0.05	3.5 (1.5-8.3)	0.005
Presence of central venous line	20 (44)	10 (19)	2 (4)	5.6 (1.0-32.7)	0.06	4.5 (0.9-22.5)	0.07
Presence of Foley catheter	38 (83)	28 (52)	16 (28)	6.0 (2.0-18.2)	0.002	2.2 (1.0-5.0)	0.06
Surgery	18 (38)	13 (23)	8 (14)	0.8 (0.2-3.2)	0.76	1.1 (0.4-3.4)	0.86
Nonsurgical procedure	18 (38)	10 (18)	1 (2)	12.5 (1.3-124.8)	0.03	8.0 (0.9-69.3)	0.06
ICU stay	18 (38)	10 (18)	1 (2)	9.6 (1.0-92.8)	0.05	7.5 (0.8-68.1)	0.07
Mechanical ventilation	22 (49)	10 (18)	2 (4)	5.2 (0.9-30.7)	0.07	4.2 (0.8-21.2)	0.09
Dialysis	4 (9)	1 (2)	0 (0)
High invasive device score	28 (58)	14 (25)	4 (7)	5.7 (1.5-22.1)	0.01	3.3 (1.0-11.4)	0.06
Receipt of antibiotics	39 (83)	19 (34)	11 (19)	6.2 (1.9-20.3)	0.003	1.4 (0.5-3.7)	0.51

↵ a The median age of the patients with CRKP infection was 77 years (IQR, 63 to 83 years), that of the patients with CSKS infection was 77 years (IQR, 65 to 84 years), and that of the hospitalized controls was 68 years (IQR, 53 to 77 years). In the time-adjusted comparison of patients with CRKP and controls, the OR for the median age was 1.04 (95% CI, 1.01 to 1.08; P = 0.02); and in the time-adjusted comparison of patients with CSKS and controls, the OR for the median age was 1.04 (95% CI, 1.01 to 1.06; P = 0.007).

TABLE 3.

Case-control comparison of antibiotic use by class^a

Antibiotic class	No. (%) of patients		P
Antibiotic class	CRKP	Controls	P
β-Lactams	28 (58)	12 (20)	<0.001
β-Lactam-β-lactamase inhibitor combinations	7 (15)	1 (2)	0.02
Aminoglycosides	13 (27)	2 (3)	<0.001
Fluoroquinolones	13 (27)	4 (7)	0.007
Carbapenems	15 (31)	0 (0)	<0.001
Other antibiotic classes	31 (65)	4 (7)	<0.001

↵ a A similar comparison between the CSKS group and the controls revealed no results with P values of ≤0.05.

TABLE 4.

Multivariable model of risk factors for Klebsiella sp. isolation

Covariate	Time-adjusted comparison of patients with CRKP and controls		Time-adjusted comparison of patients with CSKS and controls
Covariate	OR (95% CI)	P	OR (95% CI)	P
Malignancy			3.2 (1.2-9.0)	0.02
Poor functional status	15.4 (4.0-58.6)	<0.001	6.3 (2.3-17.2)	<0.001
Nonsurgical procedure			9.4 (1.0-92.6)	0.05
ICU stay	17.4 (1.5-201.9)	0.02	12.5 (1.3-125.4)	0.03
Receipt of antibiotics^a	4.4 (1.0-19.2)	0.05
Receipt of a fluoroquinolone	7.2 (1.1-49.4)	0.04
Length of stay prior to enrollment	1.08 (1.00-1.17)	0.06	1.02 (0.96-1.08)	0.61

↵ a Carbapenems could not be entered independently into the model, as no members of the control group received antibiotics from this class.

TABLE 5.

Univariate predictors of mortality for entire cohort

Covariate	No. (%) of patients^a who:		P
Covariate	Died (n = 29)	Lived (n = 134)	P
Male sex	14 (48)	51 (38)	0.40
Diabetes mellitus	10 (36)	38 (28)	0.50
Cardiovascular disease	14 (50)	88 (66)	0.14
Pulmonary disease	8 (29)	24 (18)	0.20
Renal disease	10 (36)	27 (20)	0.09
Liver disease	4 (14)	5 (4)	0.05
Neurologic disease	8 (29)	38 (28)	1.00
Malignancy	13 (46)	30 (22)	0.02
Immunosuppression	8 (29)	15 (11)	0.03
High no. of comorbidities	13 (45)	45 (34)	0.29
Admission from an institution	6 (21)	24 (18)	0.61
Transplantation	1 (4)	1 (1)	0.32
Poor functional status	17 (59)	43 (32)	0.01
High Charlson cormobidity index score	14 (48)	39 (29)	0.05
Presence of central venous line	13 (48)	19 (15)	<0.001
Presence of Foley catheter	24 (83)	58 (45)	<0.001
Surgery	9 (31)	30 (22)	0.34
Nonsurgical procedure	9 (31)	20 (15)	0.06
ICU stay	12 (41)	17 (13)	<0.001
Mechanical ventilation	17 (61)	17 (13)	<0.001
Dialysis	3 (10)	2 (2)	0.04
Receipt of antibiotics	22 (79)	47 (35)	<0.001
Isolation of Klebsiella	28 (97)	76 (57)	<0.001
Carbapenem resistant	21 (72)	27 (20)
Carbapenem susceptible	7 (24)	49 (37)

↵ a The median age for the patients who died was 75 years (IQR, 65 to 84 years), and that of the patients who lived was 73 years (IQR, 60 to 81 years) (P = 0.43). The median length of stay for the patients who died was 19 days (IQR, 10 to 30 days), and that of the patients who lived was 2 days (IQR, 1 to 8 days) (P < 0.001).

TABLE 6.

Multivariable risk factors for mortality

Covariate	Patients with CRKP vs patients with CSKS		Patients with CRKP vs hospitalized controls
Covariate	OR (95% CI)	P	OR (95% CI)	P
Carbapenem-resistant Klebsiella^a	5.4 (1.7-17.1)	0.005	6.7 (2.4-18.8)	<0.001
Mechanical ventilation	4.9 (1.6-14.7)	0.005		NS^b
Malignancy	3.9 (1.2-12.2)	0.02		NS

↵ a After introduction of the McCabe score variable into the models, the isolation of CRKP remained an independent predictor of in-hospital mortality, albeit with a lower OR (for patients with CRKP versus those with CSKS, OR, 3.9; 95% CI, 1.1 to 13.6; P = 0.03; for patients with CRKP versus controls, OR, 5.0; 95% CI, 1.7 to 14.8; P = 0.004).
↵ b NS, not significant.