Pyogenic Liver Abscesses Patients With Diabetes Mellitus Induced by Klebsiella Pneumoniae Are More Prone to Organ Dysfunction

Background Diabetes mellitus (DM) has become a common risk factor for pyogenic liver abscess (PLA) patients, Klebsiella pneumoniae is a primary pathogen of PLA (KPLA). The purpose of this study was to evaluate the clinical and microbiological characteristics in PLA patients with or without DM induced by Klebsiella pneumoniae or not. Methods The clinical data of the total 557 PLA patients were collected in Zhongshan Hospital from January 2015 to December 2020. The liver abscess were conrmed using abdominal ultrasound (US)(cid:0) computerized tomography (CT), and/or magnetic resonance imaging (MRI). The 557 patients were divided into two groups, PLA with DM and PLA without DM. In the group of PLA with DM, the patients were further separated into KPLA with DM and non-KPLA with DM. Results The total of 557 patients with PLA were analyzed, 225 (40.40%) patients comorbided DM. Among PLA patients with DM, there is a higher proportion of patients with hypertension (42.22%) and fatty liver diseases (38.67%), the most common clinical manifestation is frail and (18.22%), and more likely to progress The PLA patients with DM have higher inammatory markers (WBC, N%, CRP, ESR and PCT). There was signicant difference between the group of PLA with DM and PLA without DM in the percentage of neutrophils, liver enzymes, albumin, glucose metabolism (blood glucose, glycated hemoglobin and glycated albumin), lipid metabolism (triglycerides, low density lipoprotein, high density lipoprotein), blood sodium and chlorine, blood urea nitrogen and higher heart markers ( proBNP and CK-MB). In KPLA patients with DM compared with non-KPLA with DM, inammatory markers (WBC, N%, CRP, ESR and PCT), liver function index (TB, CB, ALT, AST, ALP and r-GT) and cardiac markers (cTnT and proBNP) are more higher. The level of albumin, serum sodium and ferritin are more lower between the KPLA patients with DM and non-KPLA with DM. Detection of liver abscess by high-throughput sequencing is more sensitive and accurate. There was no in-hospital mortality. Conclusions The study found that in the PLA patients with diabetic DM, Klebsiella pneumoniae infection is the most common, which is more prone to organ dysfunction and electrolyte disorder. High-throughput sequencing can help early diagnosis and accurate treatment of PLA patients.

The number of PLA has notably elevated in recent years and K. pneumoniae emerged as a lifethreatening bacterial pathogen across Asian and European countries, as well as the United States [6]. PLA accounts for almost half of the visceral abscess cases. Life-threatening sepsis can develop in patients with PLA. The factors of patients with immune impairment, such as diabetes mellitus, biliary diaesse, malignant tumor and alcoholism are risk for PLA [7]. The DM prevalence is relatively high among PLA patients, and the DM patients are also more susceptible to septic metastatic complications from PLA.
In terms of causative pathogens, Klebsiella pneumoniae has found as a predominant pathogen in PLA, and mainly associated with hypervirulence. Klebsiella pneumoniae, of a species of Enterobacteriaceae associated the most clinically relevant species, was rstly isolated from liver abscesses in Taiwan. The condition is frequently associated with severe complications, including septic endophthalmitis and other extrahepatic lesions, especially in patients with diabetes [8]. The conditions of patients infected with K. pneumoniae causing liver abscess are always serious, posing a great threat to public health and has attracted the attention of clinicians.
However, the different characteristic of the clinical and pathogenic features form the diabetic patients with liver abscesses induced by Klebsiella pneumoniae or not have received little attention in the literature. Therefore, the present study aimed to investigate the clinical, laboratory rests and microbiological characteristics of KPLA from DM and non-DM patients in the recent ve years and to aid in the current management of this complex condition and to improve its clinical outcome.

Patients
In this retrospective study, all of the hospitalized and consecutive patients diagnosed with PLA and treated at Department of Emergency Medicine, Zhongshan hospital, Fudan University, Shanghai, China, from January 2015 to December2020 were enrolled. The diagnosis of PLA was based on the following criteria: 1) clinical features, such as fever, chills, abdominal fullness, and abdominal pain; 2) imaging evidence of the abscess cavity in the liver as judged by abdominal ultrasonography (US), computerized tomography (CT), or magnetic resonance imaging (MRI). Patients were excluded who did not have clear records or did not complete the treatment. This study was approved by the Ethics Committee of Zhongshan Hospital Fudan University (B2021-542), Clinical Research Registration No: ChiCTR2100049219. The patient's informed written consent to analysis of their medical records was waived due to the retrospective nature of this study.

Data collection
All data were collected from the electronic medical records database. The general records included age, sex, symptoms and signs, imaging features, diagnoses, medicine use, catheter drainage and length of hospital stay. Laboratory results at admission were obtained, containing blood routine, organ function markers, coagulation, glucose metabolism, lipid metabolism, blood and pus culture, the nest generation sequencing of plasma and pus.

Statistical analysis
The data was analysed using the SPSS version 22.0 statistical software package (IBM, Armonk, NY).
Continuous variables were presented as the mean with the standard deviation (SD) and the Student's ttest was used to evaluate the differences in continuous variables. The categorical variables were reported as absolute numbers and percentages and compared by the chi-square or Fisher's exact test. Univariate and multivariate analysis were performed by the logistics regression. A two-sided P value < 0.05 was indicated statistical signi cance.

Results
Demographic and clinical characteristic of the total patient population During the study period, a total of 584 patients diagnosed as pyogenic liver abscess were inclded. Table  1  Laboratory data recorded on admission was shown in Table 2A. There were signi cant differences in glucose metabolism between the diabetic and non-diabetic groups. In PLA with DM groups, in ammatory biomarkers were generally elevated, which included leukocyte and neutrophil count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT). Statistically signi cant differences between patients with or without DM were observed in neutrophilic granulocyte percentage (N%) (P = 0.034), total bilirubin (TB) (P = 0.022), conjugated bilirubin (CB) (P = 0.01), alkaline phosphatase (ALP) (P = 0.004), Albumin (P = 0.001), low density lipoprotein (P < 0.001), high density lipoprotein (P = 0.001), Apolipoprotein A (P = 0.013), blood sodium (P = 0.003) and chlorine (P = 0.032).  (Table 2B). However, signi cant differences were observed between KPLA and non-KPLA with DM patients in PCT (P=0.008), AST (P =0.026) and γ-GT (P = 0.032) Of the 549 patients with liver abscess, patients in the sepsis group were older and had a higher ratio of males. There were statistical difference in pulmonary infection, abdominal infection, pleural effusion and abdominal effusion between sepsis and non-sepsis group. In laboratory datas, WBC, N%, CRP, PCT and TNFα sepsis group was signi cantly higher than the non-sepsis group. Sepsis patients have a higher mortality rate (Table 3).   As the technology matures, next-generation sequencing NGS had also been used in PLA patients in recent years. We analyzed 27 plasma/pus samples from PLA patients by NGS. The sensitivity of NGS was 75% in plasma and 95.42% in pus, which was obviously higher than the traditional bacterial culture Table 6.

Discussion
Pyogenic liver abscess (PLA) remians a condition associated with increasing incidence in China and throughout the world, especially in Asia. A few studies attempted to investigate the characteristics of PLA induced by Klebsiella pneumoniae in DM patients. In this retrospective study, we studied the 557 PLA cases in Shanghai, and analyzed the clinical characteristicals and microbiological data.
In our study, PLA patients with DM induced by Klebsiella pneumoniae have a higher incidence of organ dysfunction compared without DM. Diabetes is known as an important risk factor for KPLA [9,10]. Accumulating evidence in Taiwan has shown a direct relationship between PLA and Klebsiella pneumoniae (KP) in patients with Diabetes Mellitus (DM) [11][12][13]. A poor glycemic control could impair the neutrophil phagocytosis and promote growth of pathogen in tissues, while metabolic disorders could negatively in uence the liver [14]. Defects in leukocyte function, complement de ciencies and the antioxidant systems related to antibacterial activity may be associated with the pathophysiology of infections related to DM with PLA [15]. Therefore, the blood sugar level should be strictly monitored and controlled for KP-PLA patients. A recent study from Taiwan conducted a retrospective cohort study to examine the association between newly diagnosed T2DM and PLA. The T2DM cohort exhibited higher PLA risk than did the comparison cohort (hazard ratio = 2.83, 95% con dence interval = 2.32-3.46). In the T2DM cohort, the most common PLA causative agent was Klebsiella pneumonia (KP) [16]. Increased PLA risk in patients with DM was also reported in Danish large nationwide case-control study [17], according to which individuals with DM had a 3.6-fold increased PLA risk. In Canada, an epidemiological study showed that the relative risk of PLA to be 11.1 in patients with DM [18].
Among DM patients with liver abscess, there is a higher proportion of patients with hypertension and fatty liver, the most common clinical manifestations are poor tolerance and fatigue, and more likely to progress to sepsis and metastatic infections such as periorbital infection. A retrospective study demonstrated that PLA patients with diabetes are older, have more serious complications, a higher prevalence of cardiovascular disease, an increased use of combined antibiotic therapy with carbapenem, and K. pneumoniae as the predominant pathogen, poorly controlled glycaemia in diabetic PLA patients is associated with high incidence of fever and both lobes abscess [19]. In a study, 177 PLA patients (45.2%) underwent abdominal surgery before. PLA patients with a previous abdominal surgery history were more likely to have underlying diseases and presented with more abnormal laboratory values. Klebsiella pneumonia and Escherichia coli were the most common pathogens. More PLA patients without a previous abdominal surgery history required surgical drainage [20]. The proportion of PLA patients with DM was 26.87%. In the DM group, there was a higher incidence of hypertension and Candida spp. infection. Conservative administration and percutaneous drainage were mainly used in patients with good-(60.87%) and poor-control (60.53%) of glycaemia, respectively [21]. Comorbidities including hypertension, diabetes mellitus, and cholelithiasis were more frequently found in older patients. The laboratory abnormalities and imaging ndings were similar between the two groups. They found elderly PLA patients were more likely to have underlying diseases and tended to have atypical presentations [22].
Patients with diabetic liver abscess have higher in ammatory markers, more abnormal organ function markers. A study included 404 patients with a liver abscess con rmed by clinical presentation and computed tomography. Results AKI occurred in 137 patients (34 %) [23]. Recently, one study found that KPLA patients with and without sepsis had many distinct clinical features. Metabolic disorders, including fatty liver, chronic renal insu ciency and hepatic dysfunction are common underlying conditions in patients with sepsis [24]. CRP is a sensitive in ammation index that usually increases after the onset of the disease. The PCT level increases in the early stage of the systemic in ammatory response that is caused by a bacterial infection. The laboratory outcomes revealed that the majority of patients underwent in ammation and impaired liver function, and further progressed to fearful septicemia or septic shock [15,25,26].
The bacterial species identi ed from blood and pus taken from liver abscesses are summarized in Table   5 and Table 6. A retrospective review of medical records from all patients with KP-PLA admitted to a tertiary teaching hospital over a 21-year period (1994-2015) was performed. Among 296 PLA cases with con rmed culture-positive data, K. pneumoniae was revealed as the predominant pathogen (n = 189, 63.9%), followed by Escherichia coli (n = 39, 13.2%). Strikingly, KP-PLA patients had a higher incidence of metabolic disorders, such as diabetes mellitus, hypertension and fatty liver than those with non-K. pneumoniae induced PLA (non-KP-PLA). Moreover, patients with KP-PLA had higher susceptibility to septic metastatic infection at distant sites compared to those with non-KP-PLA [27]. Septic pulmonary embolism caused by a K. pneumoniae liver abscess combined with the metastatic infection of other vital organs confers a poor prognosis [28]. It found that K. pneumoniae was the main pathogen that caused the bacterial liver abscess, compared with E. coli [29][30][31]. In a retrospective study, a total of 102 nonrepetitive strains of bacteria from 178 patients were isolated, including Klebsiella pneumoniae (82 strains, 80.3%), Escherichia coli (8 strains), Pseudomonas aeruginosa (2 strains), Acinetobacter baumannii (1 strain), and Gram-positive cocci (9 strains).
Detection of liver abscess by high-throughput sequencing is more sensitive and accurate. For patients who diagnosed with KP-PLA, percutaneous drainage under ultrasonography or computed tomography guidance combined with a proper antimicrobial therapy has been taken as a standard treatment into consideration. Drainage may contribute to a better control of infection source, accurate identi cation of pathogens, and rational application of antibiotics [32].
There were several limitations to this study. First, this was a retrospective study from a single center, and some newly developed laboratory tests may not been conducted in previous cases. Second, substantial differences in etiology, treatment and outcomes of PLA should be considered. Third, some patients were not observed for a long period of time. A prospective multicentric study should be performed to validate our ndings. However, the results are based on a large number of cases and should be valuable to other investigators and clinicians.

Conclusion
In patients with diabetic liver abscess, Klebsiella pneumoniae infection is the most common, which is more prone to organ dysfunction and electrolyte disorder. High-throughput sequencing can help early diagnosis and accurate treatment of PLA patients.