Risk Factors for and Clinical Outcomes of Carbapenem-Resistant Klebsiella pneumoniae Nosocomial Infections: A Retrospective Study in a Tertiary Hospital in Beijing, China

Figures & data

Table 1 Distribution of Nosocomial CRKP Infections Among Departments

Departments	CRKP [n (%)]
ICU	55 (38.7)
General medicine ward	12 (8.5)
Rehabilitation medicine ward	9 (6.3)
Neurology ward	7 (4.9)
Respiratory medicine ward	5 (3.5)
Gastrointestinal surgery ward	14 (9.9)
Hepatobiliary and pancreatic surgery ward	12 (8.5)
Urology surgery ward	6 (4.2)
Emergency observation room	13 (9.2)
Other wards	9 (6.3)
Total	142 (100)

Abbreviations: CRKP, carbapenem-resistant Klebsiella pneumoniae; ICU, intensive care unit.

Table 2 Infection Types in the CRKP and CSKP Groups

Infection Types	CRKP Group [n (%)]	CSKP Group [n (%)]	P-value
Respiratory tract infections	57 (40.1)	78 (54.9)	0.17
Urinary tract infections	37 (26.1)	27 (19.0)
Intra-abdominal infections	28 (19.7)	22 (15.5)
Bloodstream infections	12 (8.5)	6 (4.2)
Wound and soft tissue infections	5 (3.5)	3 (2.1)
Intra-cranial infections	3 (2.1)	6 (4.2)
Total	142 (100)	142 (100)

Abbreviations: CRKP, carbapenem-resistant Klebsiella pneumoniae; CSKP carbapenem-susceptible Klebsiella pneumonia.

Table 3 Risk Factors for Nosocomial CRKP Infections

Risk Factors	CRKP Group [n (%)]	CSKP Group [n (%)]	Univariate Analysis		Multivariate Analysis
			P-value	OR (95% CI)	P-value	OR (95% CI)
Demographics
Male	87 (61.3)	85 (59.9)	0.808	/
Female	55 (38.7)	57 (40.1)
Age (years), (mean, SD)	65.08± 17.22	66.28±16.25	0.547	0.996 (0.982–1.010)
ICU stay within 3 months	96 (67.6)	76 (53.5)	0.016	1.812 (1.119–2.935)	0.638	1.188 (0.580–2.432)
Exposure to antibiotics within 3 months	61 (43)	36 (25.4)	0.002	2.217 (1.340–3.668)	0.002	2.585 (1.425–4.691)
Underlying diseases
Pulmonary disease	15 (10.6)	20 (14.1)	0.368	0.720 (0.353–1.471)
Cardiovascular disease	61 (43)	75 (52.8)	0.097	0.673 (0.421–1.074)
Liver disease	14 (9.9)	18 (12.7)	0.454	0.753 (0.359–1.581)
Neurologic disease	46 (32.4)	53 (37.3)	0.384	0.805 (0.493–1.312)
Malignancy	14 (9.9)	25 (17.6)	0.061	0.512 (0.254–1.031)
Diabetes mellitus	39 (27.5)	36 (25.4)	0.686	1.115 (0.658–1.890)
Autoimmune diseases	5 (3.5)	2 (1.4)	0.267	2.555 (0.487–13.391)
Emergency surgery within 1 month	75 (52.8)	68 (47.9)	0.406	1.218 (0.765–1.941)
Blood transfusion	49 (34.5)	28 (19.7)	0.006	2.145 (1.251–3.678)	0.227	1.509 (0.774–2.942)
Biochemical indicators
Albumin (g/L), (mean, SD)	31.75±4.22	33.26±5.49	0.01	0.939 (0.894–0.986)	0.970	0.999 (0.939–1.062)
Prealbumin (mg/L), median (IQR)	106.5 (54.0, 170.0)	113.0 (57.7, 187.5)	0.59	0.999 (0.996–1.002)
Creatinine (µmol/L), median (IQR)	64.0 (42.2,99.5)	64.9 (44.9, 86.1)	0.772	1.00 (0.998–1.003)
APACHE II score, median (IQR)	20.0 (14.0, 25.0)	22.0 (14.0, 25.0)	0.551	0.984 (0.933–1.037)
Drainage tube
Thoracic drainage tube	16 (11.3)	7 (4.9)	0.057	2.449 (0.975–6.150)
Abdominal drainage	49 (34.5)	34 (23.9)	0.051	1.674 (0.997–2.809)
Ventricular drainage tube	6 (4.2)	12 (8.5)	0.152	0.478 (0.174–1.311)
Central venous catheters	85 (59.9)	70 (49.3)	0.074	1.534 (0.959–2.454)
Arterial catheters	68 (47.9)	51 (35.9)	0.041	1.640 (1.019–2.637)	0.435	0.735 (0.339–1.593)
Tracheal cannula and mechanical ventilation	62 (43.7)	49 (34.5)	0.115	1.471 (0.911–2.375)
Foley catheter	119 (83.8)	101 (71.7)	0.011	2.1 (1.181–3.734)	0.357	1.421 (0.672–3.006)
Nasogastric tube	115 (81)	79 (55.6)	0.001	3.397 (1.991–5.794)	0.005	2.796 (1.369–5.712)
Intravenous nutrition	65 (45.8)	39 (27.5)	0.001	2.229 (1.359–3.656)	0.120	1.607 (0.884–2.919)
Types of antibiotics before a positive culture
3rd- or 4th-generation cephalosporins	32 (22.5)	26 (18.3)	0.378	1.298 (0.727–2.317)
Carbapenems	65 (45.8)	28 (19.7)	0.001	3.437 (2.025–5.833)	0.003	2.532 (1.376–4.660)
β-Lactam/β-lactamase inhibitor combinations	76 (53.5)	50 (35.2)	0.002	2.119 (1.315–3.413)	0.456	1.242 (0.703–2.195)
Fluoroquinolones	22 (15.5)	9 (6.3)	0.016	2.709 (1.201–6.114)	0.010	3.309 (1.326–8.257)
Glycopeptides	41 (28.9)	14 (9.9)	0.001	3.711 (1.918–7.184)	0.059	2.065 (0.972–4.338)
Antifungal medication	13 (9.2)	8 (5.6)	0.261	1.688 (0.677–4.207)

Abbreviations: CRKP, carbapenem-resistant Klebsiella pneumoniae; CSKP carbapenem-susceptible Klebsiella pneumonia; ICU, intensive care unit; SD, standard deviation; IQR, interquartile range; OR, odds ratio; CI, confidence interval.

Table 4 Clinical Outcomes in the Two Groups

Outcomes	CRKP Group [n (%)]	CSKP Group [n (%)]	P-value
30-day mortality	28 (19.7)	13 (9.2)	0.011
In-hospital mortality	41 (28.9)	20 (14.1)	0.002
LOS (days), median (IQR)	50.5 (30, 110.25)	33.5 (18.75, 61.25)	0.001

Abbreviations: CRKP, carbapenem-resistant Klebsiella pneumoniae; CSKP carbapenem-susceptible Klebsiella pneumonia; LOS, length of hospital stay; IQR, interquartile range.

Figure 1 Kaplan–Meier curves showing 30-day mortality in the CRKP group versus the CSKP group (P = 0.044).

Table 5 Univariable and Multivariable Analyses of In-Hospital Mortality in the Nosocomial CRKP Infection Group

Variable	CRKP Non-Survivors (41) [n (%)]	CRKP Survivors (101) [n (%)]	Univariate Analysis		Multivariate Analysis
			P-value	OR (95% CI)	P-value	OR (95% CI)
Demographics
Male	22 (53.7)	65 (64.4)	0.236	1.559 (0.747–3.257)
Female	19 (46.3)	6 (35.6)
Age (years), (mean, SD)	70.20±14.958	63.01±17.824	0.027	1.027 (1.003–1.052)	0.375	1.018 (0.979–1.059)
ICU stay within 3 months	31 (75.6)	63 (62.4)	0.134	1.870 (0.825–4.240)
Exposure to antibiotics within 3 months	14 (34.2)	47 (46.5)	0.179	0.596 (0.280–1.267)
Underlying diseases
Pulmonary disease	7 (17.1)	8 (7.9)	0.116	2.393 (0.806–7.103)
Cardiovascular disease	15 (36.6)	46 (45.5)	0.33	0.690 (0.327–1.455)
Liver disease	5 (12.2)	9 (8.9)	0.553	1.420 (0.445–4.525)
Neurologic disease	12 (29.3)	34 (33.7)	0.612	0.815 (0.370–1.795)
Malignancy	3 (7.3)	11 (10.9)	0.52	0.646 (0.171–2.447)
Diabetes mellitus	13 (31.7)	26 (25.7)	0.471	1.339 (0.605–2.965)
Autoimmune diseases	1 (2.4)	4 (4.0)	0.659	0.606 (0.066–5.593)
Emergency surgery within 1 month	16 (39.0)	59 (58.4)	0.038	0.456 (0.217–0.957)	0.870	0.912 (0.301–2.764)
Blood transfusion	18 (43.9)	31 (30.7)	0.136	1.767 (0.837–3.733)
Biochemical indicators
Albumin (g/L), (mean, SD)	30.85±3.33	32.12±4.50	0.105	0.929 (0.849–1.016)
Prealbumin (mg/L), median (IQR)	83.8 (40.5, 129.0)	114.0 (57.5, 201.0)	0.024	0.993 (0.988–0.999)	0.424	0.997 (0.989–1.005)
Creatinine (µmol/L), median (IQR)	76.9 (44.9, 146.0)	59.8 (41.5, 88.9)	0.007	1.007 (1.002–1.012)	0.013	1.009 (1.002–1.016)
PCT (ng/mL), median (IQR)	1.3 (0.4, 6.7)	0.3 (0.1, 1.6)	0.098	1.028 (0.995–1.061)
APACHE II score, (mean, SD)	17.0 (15.0, 22.5)	10.0 (7.5, 15.5)	0.177	1.015 (0.899–1.090)
Drainage tube
Thoracic drainage tube	5 (12.2)	11 (10.9)	0.824	1.136 (0.369–3.502)
Abdominal drainage	12 (29.3)	37 (36.6)	0.404	0.716 (0.326–1.569)
Ventricular drainage tube	3 (7.3)	3 (3.0)	0.259	2.579 (0.498–13.332)
Central venous catheters	28 (68.3)	57 (56.4)	0.194	1.663 (0.773–3.578)
Arterial catheters	26 (63.4)	42 (41.6)	0.02	2.435 (1.152–5.148)	0.399	0.437 (0.064–2.996)
Tracheal cannula and mechanical ventilation	25 (61.0)	37 (36.6)	0.009	2.703 (1.281–5.703)	0.159	3.784 (0.594–24.120)
Foley catheter	38 (92.7)	81 (80.2)	0.079	3.128 (0.876–11.137)
Nasogastric tube	36 (87.8)	79 (78.2)	0.193	2.005 (0.703–5.718)
Intravenous nutrition	20 (48.8)	45 (44.5)	0.647	1.185 (0.573–2.453)
Kinds of antibiotic before positive culture
3rd- or 4th-generation cephalosporins	10 (24.4)	22 (21.8)	0.736	1.158 (0.493–2.724)
Carbapenems	17 (41.5)	48 (47.5)	0.512	0.782 (0.375–1.629)
β-Lactam/β-lactamase inhibitors	22 (53.7)	54 (53.5)	0.983	1.008 (0.487–2.087)
Fluoroquinolones	9 (22.0)	13 (12.9)	0.18	1.904 (0.743–4.880)
Glycopeptides	12 (29.3)	29 (28.7)	0.947	1.027 (0.462–2.284)
Antifungal medication	5 (12.2)	8 (7.9)	0.427	1.615 (0.495–5.264)
State at the time of a positive culture
Shock	20 (48.8)	11 (10.9)	0.001	7.792 (3.246–18.706)	0.013	4.454 (1.374–14.443)
Co-infection with other resistant bacteria	32 (78.1)	51 (50.5)	0.003	3.486 (1.511–8.043)	0.024	4.799 (1.229–18.740)
Appropriate definitive treatment	15 (36.6)	33 (32.7)	0.655	1.189 (0.556–2.541)

Abbreviations: CRKP, carbapenem-resistant Klebsiella pneumoniae; CSKP carbapenem-susceptible Klebsiella pneumonia; ICU, intensive care unit; SD, standard deviation; IQR, interquartile range OR, odds ratio; CI, confidence interval.