Clinical features and risk factors for pyogenic liver abscess caused by multidrug-resistant organisms: A retrospective study

Figures & data

Table 1. Baseline characteristics of the study patients (N = 239).

Characteristic	Value
Age (years), mean ± SD	56.6 ± 14.6
Hospitalization days (day), mean ± SD	26.3 ± 24.5
Abscess size (mm), mean ± SD	66.1 ± 31.2
Sex (male), n (%)	168 (70.3)
Antibacterial drug use within 6 months before onset, n (%)	52 (21.8)
Hospitalization within 6 months before onset, n (%)	78 (32.6)
Origin, n (%)
Cryptogenic	108 (45.2)
Direct dissemination	47 (19.7)
Biliary origin	71 (29.7)
Hematogenous dissemination	13 (5.4)
Comorbidities, n (%)
Diabetes	83 (34.7)
Hypertension	74 (31.0)
Cirrhosis/hepatic failure	21 (10.5)
Malignant tumour	57 (23.8)
Cardiovascular disease	9 (3.8)
Chronic renal insufficiency	4 (1.7)
Cerebrovascular disease	11 (4.6)
Abscess location, n (%)
Right lobe	160 (66.9)
Left lobe	40 (16.7)
Bilateral	39 (16.3)
Number of abscesses, n (%)
Single	164 (68.6)
Two or more	75 (31.4)
Pathogen Quantity, n (%)
Single species	204 (85.4)
Two species	30 (12.6)
Three species	5 (2.1)
Treatment, n (%)
Antimicrobial agents alone	74 (31.0)
Antimicrobial agents and drainage	144 (60.2)
Antimicrobial agents and surgery	21 (8.8)

Figure 1. Causes of pyogenic liver abscess in the study patients (a). Distribution of multidrug-resistant organisms in patients with pyogenic liver abscess (b). CR, carbapenem-resistant; CRKP, carbapenem-resistant Klebsiella pneumoniae; ESBL, extended-spectrum beta-lactamase (producing); GNB, gram-negative bacteria; KP, Klebsiella pneumoniae; MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant enterococci.

Table 2. Comparison of the clinical characteristics, treatment, and clinical outcomes of patients with pyogenic liver abscess caused by multidrug-resistant organisms and non-multidrug-resistant organisms.

	MDRO (n = 44)	Non-MDRO (n = 131)	P
Age (years), mean ± SD	60.8 ± 12.9	56.7 ± 14.1	.088
Male sex, n (%)	34 (77.3)	88 (67.2)	.207
Body mass index, mean ± SD	21.4 ± 3.3	24.2 ± 3.9	<.001
Diabetes, n (%)	13 (29.5)	54 (41.2)	.168
Hypertension, n (%)	14 (31.8)	41 (31.3)	.949
Fatty liver, n (%)	1 (2.3)	23 (17.6)	.011
Cirrhosis/hepatic failure, n (%)	12 (27.3)	5 (3.8)	<.001
Malignant tumour, n (%)	30 (68.2)	8 (6.1)	<.001
Charlson Comorbidity Index, mean ± SD	7.0 ± 3.4	2.8 ± 2.1	<.001
Immunosuppressant use	23 (52.3)	3 (2.3)	<.001
Hospitalization within the past 6 months	36 (81.8)	14 (10.7)	<.001
Invasive procedures within the past 6 months	32 (72.7)	4 (3.1)	<.001
Antibiotic use within the past 6 months	26 (59.1)	10 (7.6)	<.001
Suspected origin of the liver abscess, n (%)			<.001
Cryptogenic	3 (6.8)	85 (64.9)
Direct spread	7 (15.9)	31 (23.7)
Biliary tract	33 (75)	14 (10.7)
Hematogenous	1 (2.3)	1 (0.8)
Clinical manifestations
Fever	42 (95.5)	128 (97.7)	.601
Disturbance	2 (4.5)	16 (12.2)	.249
Vomiting	2 (4.5)	23 (17.6)	.033
Diarrhea	0 (0.0)	11 (8.4)	.068
Headache	0 (0.0)	16 (12.2)	.013
Laboratory examination
White blood cell count (×10 [9]/L)	10.4 ± 5.0	12.4 ± 5.0	.019
Absolute lymphocyte count (×10 [9]/L)	1.0 ± 0.5	1.2 ± 0.5	.01
Neutral-lymphocyte ratio	8.4 ± 7.1	11.2 ± 8.3	.044
Hemoglobin (g/L)	95.7 ± 23.2	114.6 ± 18.7	<.001
Platelet count (×10 [9]/L)	182.5 ± 126.7	237.2 ± 144.7	.026
CRP (mg/L)	108.1 ± 52.0	120.8 ± 59.5	.209
ALT (U/L)	52.7 ± 59.4	78.6 ± 94.0	.088
AST (U/L)	60.6 ± 66.8	60.6 ± 90.0	.999
ALP (U/L)	265.8 ± 196.7	190.8 ± 106.2	.019
ALB (g/L)	29.6 ± 5.1	31.8 ± 4.7	.010
FIB (g/L)	4.9 ± 1.4	5.9 ± 2.9	.022
APTT(s)	34.6 ± 7.9	31.2 ± 6.9	.007
Imaging Results
Abscess size (mm), mean ± SD	63.8 ± 29.1	68.5 ± 26.8	.326
Abscess location, n (%)			.176
Right lobe	29 (65.9)	91 (69.5)
Left lobe	5 (11.4)	24 (18.3)
Bilateral	10 (22.7)	16 (12.2)
Treatment and clinical outcomes
Bacteremia, n (%)	24 (54.5)	46 (35.1)	.023
Metastatic abscess, n (%)	5 (11.4)	51 (38.9)	.001
Pulmonary Abscess, n (%) Endophthalmitis, n (%)	2 (4.5)	26 (19.8)	.017
	0 (0.0)	30 (22.9)	<.001
Multiple abscesses, n (%)	18 (40.9)	37 (28.2)	.117
Separated shadow, n (%)	10 (22.7)	46 (35.1)	.128
Gas liver, n (%)	12 (27.3)	2 (1.5)	<.001
Portal vein thrombus, n (%)	2 (4.5)	2 (1.5)	.263
Treatment methods			.018
Antimicrobial agents alone	7 (15.9)	48 (36.6)
Antimicrobial agents and drainage	34 (77.3)	70 (53.4)
Antimicrobial agents and surgery	3 (6.8)	13 (9.9)

ALB, albumin; ALP, alkaline phosphatase; ALT, alanine aminotransferase; APTT, activated partial thromboplastin time; AST, aspartate aminotransferase; CRP, C-reactive protein; FIB, fibrinogen/fibrin degradation products, MDRO, multidrug-resistant organism(s).

Table 3. Logistic regression analysis of risk factors associated with pyogenic liver abscess caused by multidrug-resistant organisms.

	Unadjusted OR (95% CI)	P	Adjusted OR (95% CI)	P
APTT	1.06 (1.02–1.12)	.01
ALP	1.00 (1.00–1.01)	.031
Charlson Comorbidity Index	1.67 (1.43–1.94)	<.001	1.32 (1.06–1.68)	.017
Hospitalization within the past 6 months	37.61 (14.61–96.81)	<.001	10.34 (1.86–60.30)	.007
Invasive procedures within the past 6 months	84.67 (25.60–280.03)	<.001	9.62 (1.66–71.73)	.017
Gas in the liver on imaging	24.18 (5.13–113.53)	<.001	26.00 (3.29–261.32)	.003

ALT, alanine aminotransferase; APTT, activated partial thromboplastin time; CI, confidence interval; OR, odds ratio.

Figure 2. Individualized predictive nomogram model for predicting the risk of pyogenic liver abscess caused by multidrug-resistant organisms (a). Calibration plot (b) and receiver operating characteristic (ROC) curve (c) of the nomogram model for predicting the risk of multidrug-resistant organisms in patients with pyogenic liver abscess. The figure was created using R software version 4.1.2 (R Foundation for Statistical Computing, Vienna, Austria).

Table 4. Correspondence between risk factors and points.

Factor	Points
Charlson Comorbidity Index score	5.77 points per 1 point increase
Hospitalization within the past 6 months	63
Invasive procedures within the past 6 months	51
Intrahepatic gas	93
Alkaline phosphatase level	1 point per 1 U/L increase

Table 5. Association between total points and the probability of pyogenic liver abscess being caused by an MDRO.

Total points	Odds of PLA infection being caused by MDRO
<67	<10%
67–91	10–20%
91–106	20–30%
106–119	30–40%
119–131	40–50%
131–142	50–60%
142–155	60–70%
155–171	70–80%
171–194	80–90%
>194	>90%

MDRO, multidrug-resistant organism; PLA, pyogenic liver abscess.

Table 6. Model evaluation at the optimal threshold point according to the Youden index.

Parameter	Precision	Sensitivity	Specificity	LR+
Value	0.878	0.940	0.961	0.818

LR+, positive likelihood ratio; LR−, negative likelihood ratio.

Table 7. Variance inflation factors for independent variables.

Independent variable	Variance inflation factor
Charlson Comorbidity Index score	1.52
Hospitalization within the past 6 months	2.04
Invasive procedures within the past 6 months	1.91
Intrahepatic gas	1.12
Alkaline phosphatase level	1.23

Magiorakos AP, Srinivasan A, Carey RB, et al. Multidrug-resistant, extensively drug-resistant and pandrug-resistant bacteria: an international expert proposal for interim standard definitions for acquired resistance. Clin Microbiol Infect. 2012;18(3):268–281. doi: 10.1111/j.1469-0691.2011.03570.x

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Data availability statement

All the data supporting the findings of this study are provided in the article and online at https://doi.org/10.7910/DVN/V1EYGB.