Pyogenic liver abscess as endemic disease, Taiwan

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

The incidence rate of pyogenic liver abscess caused by multidrug-resistant bacteria has increased in recent years. This study aimed to identify the clinical characteristics and risk factors for pyogenic liver abscess caused by multidrug-resistant bacteria. We conducted a retrospective analysis of the clinical features, laboratory test results, and causes of pyogenic liver abscesses in 239 patients admitted to a tertiary hospital. Multivariable logistic regression was used to identify risk factors for multidrug resistance. Among patients with pyogenic liver abscesses, the rate of infection caused by multidrug-resistant organisms was observed to be 23.0% (55/239), with a polymicrobial infection rate of 14.6% (35/239). Additionally, 71 cases (29.7%) were associated with biliary tract disease. Patients with pyogenic liver abscesses caused by multidrug-resistant organisms had a significantly higher likelihood of polymicrobial infection and increased mortality (7/44 [15.9%] vs. 3/131 [2.3%]; p = .003). The Charlson Comorbidity Index (adjusted odds ratio [aOR]: 1.32, 95% confidence interval [CI]: 1.06-1.68), hospitalization (aOR: 10.34, 95% CI: 1.86-60.3) or an invasive procedure (aOR: 9.62; 95% CI: 1.66-71.7) within the past 6 months, and gas in the liver on imaging (aOR: 26.0; 95% CI: 3.29-261.3) were independent risk factors for pyogenic liver abscess caused by multidrug-resistant bacteria. A nomogram was constructed based on the risk factors identified. The nomogram showed high diagnostic accuracy (specificity, 0.878; sensitivity 0.940). Multidrug-resistant organisms causing pyogenic liver abscesses have specific characteristics. Early identification of patients at high risk of infection with multidrug-resistant organisms could help improve their management and enable personalized treatment.

Macrophage-depleted young mice are beneficial in vivo models to assess the translocation of Klebsiella pneumonia from the gastrointestinal tract to the liver in the elderly

Pathobionts are commensal intestinal microbiota capable of causing systemic infections under specific conditions, such as environmental changes or aging. However, it is unclear how pathobionts are recognized by the intestinal mucosal immune system under physiological conditions. This study demonstrates that the gut pathobiont Klebsiella pneumoniae causes injury to the epithelium and translocates to the liver in specific pathogen-free mice treated with clodronate-liposomes that depleted macrophages. In the clodronate-liposome-treated mice, indigenous classical K. pneumoniae (cKp) with non-K1/K2 capsular serotypes were isolated from the liver, indicating that gut commensal cKp translocated from the gastrointestinal tract to the liver due to the depletion of intestinal macrophages. Oral inoculation of isolated cKp to clodronate-liposome-treated mice significantly reduced the survival rates compared to that of non-treated mice. Our findings demonstrate that intestinal mucosal macrophages play a pivotal role in sensing commensal cKp and suppressing their translocation to the liver. This study demonstrates that clodronate-liposome-treated mouse models are effective for screening and evaluating drugs that prevent the translocation of cKp to the liver, providing new insights into the development of preventive protocols against K. pneumoniae infection.

Clinical management, pathogen spectrum and outcomes in patients with pyogenic liver abscess in a German tertiary-care hospital

Pyogenic liver abscesses (PLA) are life-threatening disorders and require immediate treatment, but structured evidence is sparse and treatment guidelines are not established. In a retrospective observational study of 221 adult PLA patients (mean age 63 years, 63% men) treated between 2013 and 2019 at the Leipzig University Medical Center, we characterized pathogen spectrum, clinical management and outcomes. Biliary malignancies (33%), cholelithiasis (23%) and ischemic biliary tract disease (16%) were most common causes of PLA. Comorbidities included malignancies (40%) and diabetes mellitus (35%). Abdominal ultrasound was the preferred initial imaging modality (58%). Enterobacterales (58%), enterococci (42%) and streptococci (18%) were identified as most frequent pathogens. 97% of patients were treated with antibiotics and 75% of patients underwent an invasive treatment procedure. The 30-day mortality was almost identical in patients with and without underlying malignancy (14.6% vs. 14.4%, p = 0.96), while the one-year outcome differed significantly (58.4% vs. 29.6%, p < 0.001). Positive blood cultures (OR 4.78, 95% CI 1.39 to 22.5, p = 0.023) and detection of Enterobacterales (OR 3.55, 95% CI 1.40 to 9.97, p = 0.010) were associated with increased 30-day-mortality. We conclude that ultrasound, extensive microbiologic diagnosis, adequate anti-infective therapy and early intervention are crucial for the management of PLA.

Alterations of Gut Microbiota in Pyogenic Liver Abscess Patients with and without Type 2 Diabetes Mellitus

Purpose

The clinical manifestations of pyogenic liver abscess (PLA) vary between patients with and without diabetes mellitus (DM). However, the relationship between PLA and the gut microbiome remains unknown. This study analyzed the composition of gut microbiota in PLA patients with and without DM and healthy controls (HCs) with the goal of identifying potential reasons for the observed variations in clinical manifestations.

Patients and Methods

Using 16S ribosomal RNA(16S rRNA) gene sequencing, we analyzed the compositions of gut microbiota in 32 PLA patients with DM, 32 PLA patients without DM, and 29 matched HCs.

Results

In PLA patients with DM, the D-dimer level, fibrinogen degradation products, and thrombin time were significantly higher compared to the PLA patients without DM (P < 0.05). The abundance and diversity of intestinal flora were reduced in both groups of PLA patients compared with the HCs (P < 0.05). Specifically, the PLA patients with DM showed significant decreases in the relative abundances of Bacteroides, Blautia, Prevotella9, and Faecalibacterium, whereas Enterococcus and Escherichia-Shigella were relatively more abundant (P < 0.05). Compared to PLA patients without DM, those with DM had lower relative abundances of Lactobacillus and Klebsiella (P < 0.05) and showed different bacterial flora, including Anaerosporobacter and Megamonas.

Conclusion

PLA patients with DM exhibited more severe clinical manifestations of PLA compared to patients without DM. It is important to monitor blood coagulation in PLA patients with DM to prevent the development of thrombotic diseases. Additionally, PLA patients with DM exhibit distinct differences in the composition and diversity of their intestinal flora compared to both PLA patients without DM and HCs.

Pyogenic liver abscesses in peritoneal dialysis patients: A single-centre retrospective case series

Peritoneal dialysis (PD)-related infection rates have improved, but serious complications such as liver abscesses remain an issue, posing unique management challenges including safety of continuing PD versus early PD catheter removal. Current literature describing this is unfortunately limited. This study aims to describe the characteristics, management and outcomes of liver abscesses in PD patients from a retrospective review of prevalent PD patients on follow-up at Tan Tock Seng Hospital between 1st January 2016 and 30th June 2021. A total of 11/383 PD patients (2.9%) were treated for liver abscesses. Most were diabetic (n =10, 90.9%), with a median PD vintage of 541 days (interquartile range: 310-931 days). Fever (n = 7, 63.6%), bacteraemia (n = 7, 63.6%) and concomitant PD peritonitis (n = 7, 63.6%) were the most common presenting symptoms. Majority of patients underwent radiological aspiration of abscess in addition to antibiotics (n = 7, 63.6%). PD catheter was removed in eight patients (72.7%), with the most common indications being empirical removal due to intra-abdominal abscess (n = 5, 62.5%) followed by septic shock (n = 2, 25%) and refractory PD peritonitis (n = 1, 12.5%). Only three patients (37.5%) remained on PD, as they did not develop PD peritonitis during their course of treatment. The overall mortality remains high with three patients (27.3%) passing away within 6 months of presentation. Liver abscesses in PD patients is associated with poor technique and overall survival. Absence of PD peritonitis appears to be a good prognostic factor, but larger studies are required to guide the optimal management of liver abscesses in PD patients.

[Construction and characterization of a modA gene mutant strain of Klebsiella pneumoniae]

OBJECTIVE

To construct a mutant strain of Klebsiella pneumoniae NTUH- K2044 with modA gene deletion and its complementary strain and explore the role of modA gene in modulating anaerobic nitrate respiratory growth and phenotypes of K. pneumoniae.

METHODS

The modA deletion mutant K. pneumoniae strain was constructed by homologous recombination using the suicide vector pKO3-Km. To obtain the complementary strain C-modA, the whole sequence fragment containing the promoter, open reading frame and terminator regions of modA was cloned into pGEM-T-easy and electrically transformed into the modA deletion mutant. The NTUH-K2044 wild-type strain, modA gene deletion mutant and complementary strain were compared by measuring in vitro anaerobic nitrate respiration growth, competitiveness index, biofilm quantification, mucoviscosity assay and morphological measurement using Image J.

RESULTS

The modA deletion mutant strain ΔmodA and the complementary strain C-modA were successfully constructed. The modA gene knockout strain showed inhibited anaerobic nitrate respiratory growth compared with the wild- type and C-modA strains with significantly weakened competitiveness, reduced capacity of biofilm synthesis during anaerobiosis, and lowered mucoviscosity under anaerobic conditions. The ΔmodA strain showed a spherical morphology in anaerobic conditions as compared with the normal short rod-like morphology of K. pneumoniae, with also distinctly shorter length than the wild-type and C-modA strains.

CONCLUSION

The molybdate transport system encoding gene modA is associated with the pathogenic capacity of K. pneumoniae by modulating its anaerobic nitrate respiration, competitiveness, biofilm formation, hypermucoviscous phenotype and morphology.

The Rapid Emergence of Hypervirulent Klebsiella Species and Burkholderia pseudomallei as Major Health Threats in Southeast Asia: The Urgent Need for Recognition as Neglected Tropical Diseases

The World Health Organization (WHO)'s list of neglected tropical diseases (NTDs) highlights conditions that are responsible for devastating health, social and economic consequences, and yet, they are overlooked and poorly resourced. The NTD list does not include conditions caused by Gram-negative bacilli (GNB). Infections due to GNB cause significant morbidity and mortality and are prevalent worldwide. Southeast Asia is a WHO region of low- and middle-income countries carrying the largest burden of NTDs. Two significant health threats in Southeast Asia are Burkholderia pseudomallei (causing melioidosis) and hypervirulent Klebsiella pneumoniae (HvKp). Both diseases have high mortality and increasing prevalence, yet both suffer from a lack of awareness, significant under-resourcing, incomplete epidemiological data, limited diagnostics, and a lack of evidence-based treatment. Emerging evidence shows that both melioidosis and HvKp are spreading globally, including in high-income countries, highlighting the potential future global threat they pose. In this article, we review both conditions, identifying current trends and challenges in Southeast Asia and areas for future research. We also argue that melioidosis and HvKp merit inclusion as NTDs, and that mandatory global surveillance and reporting systems should be established, and we make an urgent call for research to better understand, detect, and treat these neglected diseases.

Structural and functional basis of bacteriophage K64-ORF41 depolymerase for capsular polysaccharide degradation of Klebsiella pneumoniae K64

Capsule polysaccharide is an important virulence factor of Klebsiella pneumoniae (K. pneumoniae), which protects bacteria against the host immune response. A promising therapeutic approach is using phage-derived depolymerases to degrade the capsular polysaccharide and expose and sensitize the bacteria to the host immune system. Here we determined the cryo-electron microscopy (cryo-EM) structures of a bacteriophage tail-spike protein against K. pneumoniae K64, ORF41 (K64-ORF41) and ORF41 in EDTA condition (K64-ORF41EDTA), at 2.37 Å and 2.50 Å resolution, respectively, for the first time. K64-ORF41 exists as a trimer and each protomer contains a β-helix domain including a right-handed parallel β-sheet helix fold capped at both ends, an insertion domain, and one β-sheet jellyroll domain. Moreover, our structural comparison with other depolymerases of K. pneumoniae suggests that the catalytic residues (Tyr528, His574 and Arg628) are highly conserved although the substrate of capsule polysaccharide is variable. Besides that, we figured out the important residues involved in the substrate binding pocket including Arg405, Tyr526, Trp550 and Phe669. This study establishes the structural and functional basis for the promising phage-derived broad-spectrum activity depolymerase therapeutics and effective CPS-degrading agents for the treatment of carbapenem-resistant K. pneumoniae K64 infections.

Literature- and Experience-Based Consensus for Acute Post-operative Endophthalmitis and Endogenous Endophthalmitis in Taiwan

Clinical practices on acute post-operative and endogenous endophthalmitis (EnE) are highly variable among clinicians due to a lack of up-to-date, high-quality evidential support. An expert consensus is thus much needed. A panel consisting of ten retinal specialists in Taiwan was organized. They evaluated relevant literature and developed key questions regarding acute post-operative and EnE that are cardinal for practice but yet to have conclusive evidence. The panel then attempted to reach consensus on all the key questions accordingly. There were eight key questions proposed and their respective consensus statements were summarized as follows: Gram staining and culture are still the standard procedures for the diagnosis of endophthalmitis. Vitrectomy is recommended to be performed earlier than the timing proposed by the Endophthalmitis Vitrectomy Study (EVS). Routine intracameral antibiotic injection for post-cataract surgery endophthalmitis prophylaxis is not recommended because of potential compounding error hazards and a lack of support from high-quality studies. Routine fundus examination is recommended for all patients with pyogenic liver abscess. In EnE, vitrectomy is recommended if diffused and dense vitritis is present, or if the disease progresses. These consensus statements may work as handy guidance or reference for clinical practices of acute post-operative and EnE.

Coexistence of c-rmpA with p-rmpA and p-rmpA2 rather than excessive siderophores confers higher virulence in K1 Klebsiella pneumoniae

Pyogenic liver abscess (PLA), which is particularly endemic in East Asia, is a relatively common and fatal infectious disease. Over the last 30-40 years, Klebsiella pneumoniae has replaced Escherichia coli as the dominant and overwhelming pathogen. To investigate the survival advantage of serotype K1 K. pneumoniae, we determined sequence types (STs), serotypes, and 11 virulence genes (allS, entB, irp2, iroN, iucA, fimH, mrkD, p-rmpA2, c-rmpA, p-rmpA, and peg-344). Virulence genes c-rmpA, p-rmpA, and p-rmpA2 in K. pneumoniae NTUH-K2044, which all confer hypercapsule and consequent hypervirulence, were deleted individually, and the consequent effects were evaluated. The lethality of various K1 K. pneumoniae strains was compared by using the Galleria mellonella model. In total, 31 K1 K. pneumoniae strains causing PLA and 30 causing non-PLA were identified. A significantly higher rate of c-rmpA was presented in PLA-derived K. pneumoniae strains than in non-PLA-derived strains. Similar ST23 (which dominates K1 strains) and string test-positive rates were observed in the two groups. Deletion of c-rmpA, p-rmpA, and p-rmpA2 individually did not confer significant effects on morphologies, such as positive string test, hypercapsule, and growth speed. Δc-rmpA presented weaker expressions of p-rmpA/p-rmpA2 than NTUH-K2044 and showed a higher expression of manC than Δp-rmpA and Δp-rmpA2. Three rmpAs conferred more virulence than one or two rmpAs, which presented an equally lethal effect in K1 K. pneumoniae. Klebsiella pneumoniae strains (H19 and H34) with the same genetic backgrounds except for siderophores showed equal virulence, but were less virulent than strain NTUH-K2044. Thus, the coexistence of c-rmpA with p-rmpA and p-rmpA2 enhances the lethality of K1 K. pneumoniae strains and the development of PLA. Excessive siderophores are not vital for the hypervirulence of K1 K. pneumoniae strains, although K1 strains usually harbour them on a molecular basis.

Severe disseminated infection by hypermucoviscous Klebsiella pneumoniae successfully treated by intensive therapy with continuous hemodiafiltration using AN69ST: A case report and review of the literature

Klebsiella pneumoniae (Kpn) is one of the most common gram-negative bacilli causing lung, urinary tract, and biliary tract infections. However, as a distinct entity from classic Kpn, hypervirulent Kpn causing liver abscess, endophthalmitis, and lung abscess with poor prognoses has been reported mainly in East and Southeast Asia since the mid-1980s. Although the definition of hypervirulent Kpn is unclear, the hypermucoviscosity of Kpn is considered an important feature of hypervirulence. We present a case of emphysematous pyelonephritis accompanied by septic shock and acute kidney injury caused by hypermucoviscous Kpn infection that was successfully treated by intensive treatment. A 70-year-old woman with type 2 diabetes mellitus was diagnosed with emphysematous pyelonephritis, and string test-positive Kpn was detected in blood and urine cultures and percutaneous catheter drainage fluid from the renal pelvis. The patient was treated with intensive therapies including antibiotics, ventilator management, and continuous hemodiafiltration (CHDF) using AN69ST, which can absorb cytokines. During the course of treatment, the infection was complicated by pyogenic spondylitis, which was cured by antimicrobial therapy, and the patient was transferred to another hospital for rehabilitation on day 119 after admission. Hypermucoviscous Kpn infection often has a severe course, and it is important to initiate multidisciplinary treatment at an early stage, including rifampicin, which is expected to inhibit the viscosity of hypermucoviscous Kpn. In the current case, immediate CHDF using AN69ST was also considered a life-saving treatment because it improved both volume overload and neutrophil-activated hypercytokinemia.

Endogenous Endophthalmitis From a Klebsiella pneumoniae Liver Abscess: The Incidence, Risk Factors, and Utility of Imaging

PURPOSE

We investigated the rate of ophthalmologic examinations to detect endogenous endophthalmitis in patients with pyogenic liver abscesses (PLAs) and the incidence and risk factors of endophthalmitis from a PLA caused by Klebsiella pneumoniae (PLA-K).

DESIGN

Retrospective case series.

METHODS

A total of 536 patients admitted to a university hospital in Korea to treat PLAs during 2012-2022 were included. The proportion of patients who were referred for ophthalmologic examinations was investigated and the incidence of endophthalmitis in 248 patients with PLA-K was calculated. Univariate and multivariate logistic regression analyses were performed to define risk factors including demographic characteristics, underlying diseases, radiologic findings, and systemic conditions.

RESULTS

A comprehensive ophthalmologic examination was performed in 73.7% of all patients with PLAs, and the incidence of endophthalmitis from a PLA-K was 7.3%. A liver abscess >5 cm increased the incidence of endogenous endophthalmitis 4-fold compared with smaller abscesses (odds ratio [OR] = 4.01 [95% confidence interval {CI}, 1.02-15.78], P = .047) and portal or hepatic vein thrombophlebitis increased the incidence approximately 4-fold (OR = 4.04 [95% CI, 1.10-14.83], P = .036). Acute cholangitis was approximately 8-fold (OR = 8.33 [95% CI, 1.25-55.71], P = .029), and disseminated intravascular coagulation was approximately 6-fold (OR = 5.76 [95% CI, 1.22-27.21], P = .027) more related to prevalence of endophthalmitis. Other extrahepatic infections increased the incidence approximately 43-fold (OR = 43.06 [95% CI, 10.14-182.90], P < .001).

CONCLUSIONS

Clinicians should consider the risk of endogenous endophthalmitis when PLA-K patients have large liver abscesses (>5 cm), acute cholangitis, portal or hepatic vein thrombophlebitis, disseminated intravascular coagulation, or other extrahepatic infections.

The New Changes of Epidemiology, Etiology, and Clinical Characteristics of Pyogenic Liver Abscesses: A Retrospective Study in a Hospital in Northern China

Purpose

To investigate the epidemiology, etiology, and clinical characteristics of patients with pyogenic liver abscesses (PLA) and provide guidance for clinical treatments.

Patients and Methods

A retrospective study was performed on a cohort of 402 hospitalized patients diagnosed with PLAs at the Affiliated Hospital of Chengde Medical College between January 2016 and December 2021. Patient demographics, drug sensitivity profiles, and microbiological culture results of drainage and blood samples were thoroughly analyzed to identify significant patterns or trends. Furthermore, clinical characteristics and treatments for patients with PLA were comprehensively assessed.

Results

Patients aged 50-69 years had the highest incidence of PLA, accounting for 59.9% of all cases, and 91.5% of them had a fever. Bacterial culture analysis of the 200 patients revealed that Klebsiella pneumoniae (K. pneumoniae) was the most predominant pathogen, detected in 70.5% of cases, exhibiting an upward trend. Escherichia coli (E. coli) was the second most frequently detected pathogen, identified in 14.5% of cases, showing a downward trend. Coexisting diabetes mellitus (DM) was found to be the most common comorbidity for PLA, occurring in most patients with the condition. Patients with a history of abdominal surgery and malignancy had an increased risk for PLA, while those with gallstones had a decreased risk. Drainage combined with antibiotic therapy was identified as the primary treatment of PLA. In addition, multivariate analysis demonstrated that coexisting DM and the presence of gas in the abscess cavity were independent risk factors for septic shock in patients with PLA.

Conclusion

This study reveals a shift in the proportions of pathogens and risk factors in patients with PLA, underscoring the necessity for improved diagnostic and therapeutic strategies.

Klebsiella pneumoniae invasive syndrome with liver abscess and purulent meningitis presenting as acute hemiplegia: a case report

BACKGROUND

Klebsiella pneumoniae can infect a variety of sites, with the risk of infection being higher in the immunocompromised state such as diabetes mellitus. A distinct invasive syndrome has been detected mostly in Southeast Asia in the past two decades. A common destructive complication is pyogenic liver abscess that can be complicated by metastatic endophthalmitis as well as the involvement of the central nervous system, causing purulent meningitis or brain abscess.

CASE PRESENTATION

We report a rare case of an invasive liver abscess caused by K. pneumoniae, with metastatic infections of meninges. A 68-year-old man with type 2 diabetes mellitus presented to our emergency department as sepsis. Sudden disturbed consciousness was noticed with presentation of acute hemiplegia and gaze preference mimicking a cerebrovascular accident.

CONCLUSIONS

The above case adds to the scarce literature on K. pneumoniae invasive syndrome with liver abscess and purulent meningitis. K. pneumoniae is a rare cause of meningitis and should raise suspicions about the disease in febrile individuals. In particular, Asian patients with diabetes presenting with sepsis and hemiplegia prompt a more thorough evaluation with aggressive treatment.

Identification of three capsule depolymerases in a bacteriophage infecting Klebsiella pneumoniae capsular types K7, K20, and K27 and therapeutic application

BACKGROUND

Klebsiella pneumoniae capsular types K1, K2, K5, K20, K54, and K57 are prevalent hypervirulent types associated with community infections, and worrisomely, hypervirulent strains that acquired drug resistance have been found. In the search for alternative therapeutics, studies have been conducted on phages that infect K. pneumoniae K1, K2, K5, and K57-type strains and their phage-encoded depolymerases. However, phages targeting K. pneumoniae K20-type strains and capsule depolymerases capable of digesting K20-type capsules have rarely been reported. In this study, we characterized a phage that can infect K. pneumoniae K20-type strains, phage vB_KpnM-20.

METHODS

A phage was isolated from sewage water in Taipei, Taiwan, its genome was analyzed, and its predicted capsule depolymerases were expressed and purified. The host specificity and capsule-digesting activity of the capsule depolymerases were determined. The therapeutic effect of the depolymerase targeting K. pneumoniae K20-type strains was analyzed in a mouse infection model.

RESULTS

The isolated Klebsiella phage, vB_KpnM-20, infects K. pneumoniae K7, K20, and K27-type strains. Three capsule depolymerases, K7dep, K20dep, and K27dep, encoded by the phage were specific to K7, K20, and K27-type capsules, respectively. K20dep also recognized Escherichia coli K30-type capsule, which is highly similar to K. pneumoniae K20-type. The survival of K. pneumoniae K20-type-infected mice was increased following administration of K20dep.

CONCLUSIONS

The potential of capsule depolymerase K20dep for the treatment of K. pneumoniae infections was revealed using an in vivo infection model. In addition, K7dep, K20dep, and K27dep capsule depolymerases could be used for K. pneumoniae capsular typing.

Diabetes and obesity and risk of pyogenic liver abscess

Few literatures discussed the relationship of glycemic control and body mass index (BMI) with the risk of pyogenic liver abscess. We conducted a population-based cohort study using participants of a community-based health screening program in Taiwan from 2005 to 2008 (n = 125,865). Information on fasting plasma glucose (FPG), BMI, and other potential risk factors of liver abscess were collected at baseline. Incidence of pyogenic liver abscess was ascertained using inpatient records from the National Health Insurance database. During a median 8.6 years of followed up, 192 incident cases of pyogenic liver abscess were reported. The incidence rate of pyogenic liver abscess was 70.2 and 14.7 per 100,000 in the diabetic and non-diabetic population respectively. In multivariable Cox regression analysis, the adjusted hazard ratio (HR) was 2.18 (95% confidence interval (CI) 1.22-3.90) in patients with diabetes with good glycemic control (FPG ≤ 130 mg/dl) and 3.34 (95% CI 2.37-4.72) in those with poor glycemic control (FPG > 130 mg/dl), when compared with non-diabetics. In the dose-response analysis, the risk of liver abscess increased monotonically with increasing FPG. After adjusting for diabetes and other comorbidities, overweight (25 ≤ BMI < 30) (adjusted HR: 1.43, 95% CI 1.05-1.95) and obese (BMI ≥ 30) (adjusted HR: 1.75, 95% CI 1.09-2.81) populations had a higher risk of liver abscess when compared to people with normal weight. Diabetes, especially poorly controlled disease, and high BMI were associated with higher risk of pyogenic liver abscess. Improving glycemic control and weight reduction may reduce the risk of developing pyogenic liver abscess.

Machine learning models for prediction of invasion Klebsiella pneumoniae liver abscess syndrome in diabetes mellitus: a singled centered retrospective study

OBJECTIVE

This study aimed to develop and validate a machine learning algorithm-based model for predicting invasive Klebsiella pneumoniae liver abscess syndrome(IKPLAS) in diabetes mellitus and compare the performance of different models.

METHODS

The clinical signs and data on the admission of 213 diabetic patients with Klebsiella pneumoniae liver abscesses were collected as variables. The optimal feature variables were screened out, and then Artificial Neural Network, Support Vector Machine, Logistic Regression, Random Forest, K-Nearest Neighbor, Decision Tree, and XGBoost models were established. Finally, the model's prediction performance was evaluated by the ROC curve, sensitivity (recall), specificity, accuracy, precision, F1-score, Average Precision, calibration curve, and DCA curve.

RESULTS

Four features of hemoglobin, platelet, D-dimer, and SOFA score were screened by the recursive elimination method, and seven prediction models were established based on these variables. The AUC (0.969), F1-Score(0.737), Sensitivity(0.875) and AP(0.890) of the SVM model were the highest among the seven models. The KNN model showed the highest specificity (1.000). Except that the XGB and DT models over-estimates the occurrence of IKPLAS risk, the other models' calibration curves are a good fit with the actual observed results. Decision Curve Analysis showed that when the risk threshold was between 0.4 and 0.8, the net rate of intervention of the SVM model was significantly higher than that of other models. In the feature importance ranking, the SOFA score impacted the model significantly.

CONCLUSION

An effective prediction model of invasion Klebsiella pneumoniae liver abscess syndrome in diabetes mellitus could be established by a machine learning algorithm, which had potential application value.

Hypercapsule is the cornerstone of Klebsiella pneumoniae in inducing pyogenic liver abscess

Purpose

To investigate the mechanisms of Klebsiella pneumoniae-induced pyogenic liver abscess (PLA).

Methods

Forty-three K. pneumoniae strains from PLAs and 436 from non-PLAs were collected. Their differences were compared for virulence genes and factors, sequence types, and serotypes. Virulence genes wzi, wzy-K1, and wzi+wzy-K1 were deleted in K. pneumoniae NTUH-K2044. Various analyses, such as transmission electron microscopy, neutrophil killing tests, and mouse lethality tests, were used to confirm the consequent changes.

Results

Differences were found between K. pneumoniae strains from PLA and non-PLA samples for virulence genes and factors, including metabolism genes (allS and peg-344), capsular polysaccharide (CPS)-synthesis channel gene (wzy-K1), CPS-regulating genes (p-rmpA, p-rmpA2, and c-rmpA), and siderophore genes (iucA and iroN). When wzy-K1 was positive, the difference between PLA and non-PLA samples was only observed with c-rmpA. Δwzi, Δwzy-K1, and ΔwziΔwzy-K1 strains reverted to hypovirulence. In the Kupffer cell stimulation assay, interleukin (IL)-6, IL-12, IL-10, and transforming growth factor-β secretions were found to be equivalent in NTUH-K2044, Δwzi, Δwzy-K1, and ΔwziΔwzy-K1 groups. Lower IL-1β and higher tumor necrosis factor-α secretions were observed for Δwzi, Δwzy-K1, and ΔwziΔwzy-K1.

Conclusions

Hypercapsule production is the cornerstone of hypervirulence, regardless of exopolysaccharides. K1 K. pneumoniae-induced PLA may decrease core inflammatory cytokines rather than increase anti-inflammatory cytokines. Exopolysaccharides could also attenuate the inflammatory response to aid in the immune escape of K. pneumoniae.

Pyogenic liver abscesses in liver transplant recipients versus non-transplant population. Outcome and risk factors of patient survival

Pyogenic liver abscess (PLA) is a life-threatening infection in both liver transplant (LT) and non-LT patients. Several risk factors, such as benign and malignant hepatopancreatobiliary diseases and colorectal tumors have been associated with PLA in the non-LT population, and hepatic artery stricture/thrombosis, biliary stricture, and hepaticojejunostomy in the LT patients. The objective of this study is to compare the outcomes of patients with PLA in LT and non-LT patients and to determine the risk factors associated with patient survival. From January 2000 to November 2020, a total of 296 adult patients were diagnosed of PLA in our institution, of whom 26 patients had previously undergone liver transplantation (LTA group), whereas 263 patients corresponded to the non-LTA population. Seven patients with PLA who had undergone previous kidney transplantation were excluded from this retrospective study. Twenty-six patients out of 1503 LT developed PLA (incidence of 1.7%). Median age was significantly higher in non-LTA patients (p = .001). No significant differences were observed in therapy. PLA recurrence was significantly higher in LTA than in non-LTA (34.6% vs. 14.8%; p = .008). In-hospital mortality was greater in the LT group than in the non-LT group (19.2% vs. 9.1% p = .10) and was identified in multivariable analysis as a risk factor for mortality (p = .027). Mortality rate during follow-up did not show significant differences between the groups: 34.6% in LTA patients versus 26.2% in non-LTA patients (p = .10). The most common causes of mortality during follow-up were malignancies, Covid-19 infection, and neurologic disease. 1-, 3-, and 5-year actuarial patient survival rates were 87.0%, 64.1%, and 50.4%, respectively, in patients of LTA group, and 84.5%, 66.5%, and 51.0%, respectively, in patients with liver abscesses in non-LTA population (p = .53). In conclusion, LT was a risk factor for in hospital mortality, but not during long-term follow-up.

Increasing incidence of pyogenic liver abscess in Southern Sweden: a population-based study from 2011 to 2020

BACKGROUND

Pyogenic liver abscess (PLA) is a rare but potentially life-threatening disease, and estimates suggest a gradual increase in the incidence during the last decades. The primary aim of this study was to report the incidence, trend and aetiology of PLA during a decade in Southern Sweden.

METHODS

This was a population-based observational cohort study between 2011 and 2020 in Skåne, Southern Sweden. Data were retrieved from the Swedish National Board of Health and Welfare for all individuals diagnosed with liver abscess (K750) according to ICD-10 (International Statistical Classification of Diseases, 10th revision).

RESULTS

A total of 456 episodes of PLA occurred in 364 patients during the study period. The median age of the first PLA episode was 71 years (range 3-97) and 57% (n = 206) were men. The mean incidence of all patients was 3.4/100,000 person-years (range 1.8-5.2). The incidence increased almost three times, from 1.8/100,000 person-years in 2011 to 5.2/100,000 person-years in 2020. Streptococcus species, Escherichia coli and Klebsiella species accounted for the vast majority of both mono- and polymicrobial findings in both blood and local abscess cultures. 16s rDNA added information about aetiology in 37% of episodes.

CONCLUSION

The incidence of PLA increased during the study period, and Streptococcus spp., Klebsiella spp. and E. coli dominated both blood and local cultures. Despite antimicrobial therapy, pathogens could be found in local abscess cultures several weeks into treatment. Increased use of 16s rDNA in the management of PLA could be beneficial.

Risk factors indicating the need for surgical therapy in patients with pyogenic liver abscesses

BACKGROUND

Percutaneous drainage (PD) and antibiotics are the therapy of choice (non-surgical therapy [non-ST]) for pyogenic liver abscesses (PLA), reserving surgical therapy (ST) for PD failure. The aim of this retrospective study was to identify risk factors that indicate the need for ST.

METHODS

We reviewed the medical charts of all of our institution's adult patients with a diagnosis of PLA between January 2000 and November 2020. A series of 296 patients with PLA was divided into two groups according to the therapy used: ST (n = 41 patients) and non-ST (n = 255). A comparison between groups was performed.

RESULTS

The overall median age was 68 years. Demographics, clinical history, underlying pathology, and laboratory variables were similar in both groups, except for the duration of PLA symptoms < 10 days and leukocyte count which were significantly higher in the ST group. The in-hospital mortality rate in the ST group was 12.2% vs. 10.2% in the non-ST group (p = 0.783), with biliary sepsis and tumor-related abscesses as the most frequent causes of death. Hospital stay and PLA recurrence were statistically insignificant between groups. One-year actuarial patient survival was 80.2% in the ST group vs. 84.6% in the non-ST (p = 0.625) group. The presence of underlying biliary disease, intra-abdominal tumor, and duration of symptoms for less than 10 days on presentation comprised the risk factors that indicated the need to perform ST.

CONCLUSIONS

There is little evidence regarding the decision to perform ST, but according to this study, the presence of underlying biliary disease or an intra-abdominal tumor and the duration of PLA symptoms < 10 days upon presentation are risk factors that should sway the surgeons to perform ST instead of PD.

Genetic and Phenotypic Characterization of Multidrug-Resistant Klebsiella pneumoniae from Liver Abscess

Cooccurrence of multidrug resistant (MDR) and hypervirulence phenotypes in liver abscess-causing Klebsiella pneumoniae (LAKp) would pose a major threat to public health. However, relatively little information is available on the genomic and phenotypic characteristics of this pathogen. This study aimed to investigate the virulence and resistance phenotype and genotype of MDR LAKp strains from 2016 to 2020. We collected 18 MDR LAKp strains from 395 liver abscess samples and characterized these strains using antimicrobial susceptibility test, string test, mucoviscosity assay, biofilm formation assay, Galleria mellonella killing assay, and whole-genome sequencing. Besides, phylogenetic and comparative genomic analyses were performed on these MDR LAKp, along with 94 LAKp genomes from global sources. Most of these MDR LAKp strains exhibited resistance to cephalosporins, quinolones, and chloramphenicol. Virulence assays revealed that only half of MDR LAKp strains exhibited higher virulence than classical MDR strain K. pneumoniae MGH78578. Importantly, we identified three ST11 KL64 hypervirulence carbapenem-resistant strains carrying blaKPC-2 and one colistin-resistant strain carrying mcr-1. Phylogenetic analysis revealed that 112 LAKp genomes were divided into two clades, and most of MDR LAKp strains in this study belonged to clade 1 (83.33%, 15/18). We also detected the loss of mucoviscosity mediated by mutations and ISKpn14 insertion in rmpA, and the latter representing a novel mechanism by which bacteria regulate RmpA system. This study provides novel insights into MDR LAKp and highlights the necessity for measures to prevent further spread of such organisms in hospital settings and the community. IMPORTANCE Pyogenic liver abscess is a potentially life-threatening suppurative infection of hepatic parenchyma. K. pneumoniae has emerged as a predominant pathogen of pyogenic liver abscess. Liver abscess-causing K. pneumoniae is generally considered hypervirulent K. pneumoniae and is susceptible to most antibiotics. Recently, convergence of multidrug resistant and hypervirulence phenotypes in liver abscess-causing K. pneumoniae was emerging and poses a major threat to public health. However, relatively little information is available on liver abscess-causing multidrug-resistant hypervirulent K. pneumoniae. In this study, we characterized phenotype and genotype of virulence and resistance of 18 multidrug-resistant hypervirulent liver abscess-causing K. pneumoniae strains collected from 395 pyogenic liver abscess cases in a tertiary teaching hospital over a 5-year period to enable in-depth understanding of this pathogen.

Enterococcal pyogenic liver abscesses: high risk of treatment failure and mortality

Enterococci are the most frequent gram-positive bacteria recovered from pyogenic liver abscesses (PLA). This study aims to analyze the impact of the presence of Enterococcus spp. on PLA outcome. We retrospectively analyzed the characteristics and outcome of all PLA cases in which Enterococcus spp. was isolated between January 2010 and September 2019 in a French university hospital and compared them to PLA without Enterococcus spp. Enterococci were recovered from 68 of the 359 (19%) PLA cases. Among the 78 isolates, Enterococcus faecalis (n = 37, 47.7%) and Enterococcus faecium (n = 32, 41%) were the most frequent. Enterococcal PLA were more often of biliary origin (79.4% versus 54.6%, p < 0.001) or post-surgical (35.3% versus 18.6%, p = 0.004). Multivariate analysis showed an independent association between the isolation of Enterococcus spp. and 3-month mortality (HR 2.51, p = 0.011), primary failure (HR 2.15, p = 0.006), but not with relapses (HR 0.86, p = 0.739). In the subgroup of enterococcal PLA, portal vein thrombosis was the only factor significantly associated with 3-month mortality (univariate HR 3.45, p = 0.023) or primary treatment failure (multivariate, HR 4.02, p = 0.006). Enterococcus spp. identification in a PLA is associated with a higher mortality and primary treatment failure.

Clinical characteristics and management of 106 patients with pyogenic liver abscess in a traditional Chinese hospital

This is a retrospective study of clinical data from 106 patients with pyogenic liver abscess (PLA) treated in a traditional Chinese hospital during the eight years preceding this publication. We aimed to provide evidence to improve the diagnosis accuracy and the treatment strategies for PLAs. We collected records of patients treated at the Guangxing Hospital, which is affiliated to the Zhejiang Traditional Chinese University in Hangzhou, and we collected their general background information, laboratory and imaging features, and clinical manifestations and outcomes to perform a retrospective analysis. Diabetes mellitus (45.3%, 48/106), biliary calculi (36.8%, 39/106), and history of abdominal surgery (15.1%, 16/106) were the three most common PLA risk factors present in our cohort. Fever and chills (95.3%, 101/106), right upper quadrant pain/epigastric discomfort (68.9%, 73/106), nausea and vomiting (38.8%, 41/106), and cough and sputum (14.2%, 15/106) were the most common clinical manifestations of PLA. Most patients had the abscesses in the right liver lobe, and the most commonly found bacteria were Klebsiella pneumoniae (54.8%, 42/76), Escherichia coli (35.1%, 27/76), and Streptococcus pneumoniae (3.9%, 3/76). Liver Doppler ultrasound is a conventional and effective method to identify liver abscesses. Most patients were treated using a percutaneous puncture under B-ultrasound guidance. Most patients (n = 104 or 98.1%) were cured, one patient (0.9%) died, and one was discharged with multiple abscesses post treatment.

FeoC from Klebsiella pneumoniae uses its iron sulfur cluster to regulate the GTPase activity of the ferrous iron channel

Bacteria depend on the ferrous iron transport (Feo) system for the uptake of ferrous iron (Fe²⁺). The Feo system is crucial for colonization and virulence of pathogens. In γ-proteobacteria, the system consists of FeoA, FeoB, and FeoC. The function of FeoA remains unknown. FeoB likely forms the channel, whose regulation has been suggested to involve its GTPase domain (part of its NFeoB domain). FeoC from Klebsiella pneumonia was found to contain a [4Fe4S] cofactor, whose presence was speculated to enhance the GTPase activity of FeoB (Hsueh, K.-L., et al., J. Bacteriol. 2013 195(20): 4726-34). We present results here that support and extend that hypothesis. We monitored the GTPase activity of FeoB by NMR spectroscopy and found that the presence of 7% FeoC-[4Fe-4S]³⁺ (the highest level of cofactor achieved in vitro) increased the GTPase rate of NFeoB by 3.6-fold over NFeoB. The effect depends on the oxidation state of the cluster; with reduction of the cluster to [4Fe-4S]²⁺ the GTPase greatly decreased the GTPase rate. From the effects of point mutations in FeoC on GTPase rates, we conclude that Lys62 and Lys68 on FeoC each contribute to increased GTPase activity on NFeoB. Mutation of Thr37 of NFeoB to Ser nearly abolished the GTPase activity. The GTPase activity of the isolated K. pneumoniae NFeoB-FeoC complex (NFeoBC) was found to be higher in KCl than in NaCl solution. We solved the X-ray structure of the NFeoBC crystallized from KCl and compared it with a prior X-ray structure crystalized from NaCl. We propose a hypothesis, consistent with these results, to explain the factors that influence the GTPase activity. Bacteria may use the oxygen-sensitive cluster as a sensor to up-regulate the gate closing speed.

Evaluation of the Diagnostic Performance of mNGS in Detecting Intra-Abdominal Infections of the Emergency Department Patients

Purpose

Intra-abdominal infections (IAI) are gradually becoming common in the emergency department, though the incidence is low and the prognosis is fair, as the symptoms are similar to other intra-abdominal diseases, rapid and accurate diagnosis of the causative agents is essential for clinical management. This study aimed to evaluate the diagnostic performance of metagenomic next-generation sequencing (mNGS) in detecting IAI in the emergency department.

Patients and Methods

This was a retrospective, single-centered study including patients admitted to the emergency department from January 1st, 2021 to August 31st, 2022 with diagnosis of IAI. The comparison between mNGS and microbial culture using paracentesis fluid samples was performed to evaluate the diagnostic performance of mNGS for IAI. Meanwhile, paracentesis fluid and peripheral blood mNGS were compared to explore the sample specificity. Further, the microbial community structure of the patients with pyogenic liver abscesses (PLA) was analyzed.

Results

Thirty-four IAI patients including 23 with pyogenic liver abscesses (PLA), 3 with parapancreatic abscesses, and 8 with other IAI were included in this study. Compared with the conventional microbial culture of paracentesis fluid, mNGS using paracentesis fluid detected more positive cases of IAI (93.75% vs 81.25%), and identified more species of pathogens, especially in obligate anaerobes and viral pathogens. Peripheral blood mNGS presented a relatively high consistency with the paracentesis fluid mNGS (91% mutual positive). The microbial community structure of PLA patients with diabetes is less diverse than that of those without diabetes. Patients with diabetes are at high risk of PLA caused by Klebsiella pneumonia.

Conclusion

mNGS has advantages in detecting IAI in the emergency department, and peripheral blood mNGS can be a non-invasive choice for early diagnosis.

Changes in clinical and CT manifestations related to liver abscesses in patients with vs. without basic diabetes mellitus before and after CT-guided interventional therapy: An observational study

PURPOSE

To explore differences in the changes of clinical and CT manifestations related to liver abscess before and after CT-guided interventional therapy between patients with and without Diabetes Mellitus (DM).

MATERIALS AND METHODS

Fifty-eight consecutive patients with liver abscesses were retrospectively enrolled in this study. All patients underwent upper abdominal contrast-enhanced CT scans before and after CT-guided interventional therapy. They were divided into two groups including the DM group (n=30) and the Non-DM group (n=28) if the liver abscess occurred in patients with and without DM, respectively. The changes in the clinical and CT manifestations related to liver abscess after CT-guided interventional therapy in both groups were statistically analyzed.

RESULTS

After CT-guided interventional therapy, the length of hospital stay, white blood cell recovery time and drainage tube removal time in the DM group were longer than in the Non-DM group (all p-values < 0.05). The incidence of postoperative complications in the DM group was higher than in the Non-DM group (p < 0.05). As shown on CT, the postoperative reduced percentage of maximum diameter of abscess cavity and the reduction rate of edema band surrounding the liver abscess in the DM group were smaller than in the Non-DM group (both p-values < 0.05). The time intervals of the previous characteristic changes on CT before and after interventional therapy in the DM group were longer than in the Non-DM group (all p-values < 0.05).

CONCLUSIONS

The liver abscesses patients with DM could not have a faster recovery and better therapeutic effect than those without DM after the CT-guided interventional therapy.

Platelet-to-White Blood Cell Ratio: A Feasible Biomarker for Pyogenic Liver Abscess

The platelet-to-white blood cell ratio (PWR) has been reported to predict the severity of patients with various diseases. However, no previous studies have assessed the use of the PWR as a prognostic marker for pyogenic liver abscesses (PLA). This observational retrospective study was performed between January 2008 and December 2017, including 833 patients with PLA from multiple centers. The enrolled patients, on average, had a PWR of 17.05, and 416 patients had a PWR lower than 17.05. A total of 260 patients (31.2%) with PLA showed complications of metastatic infection, pleural effusion and abscess rupture. A low PWR level was identified as a strong risk factor for metastatic infection and pleural effusion. The low PWR group also had a longer hospital stay. In the multivariate analysis, old age, anemia, albumin and CRP levels and unidentified pathogens were significant factors for low PWR levels. A low PWR, old age, male sex, abscess size, albumin, ALP and unidentified causative pathogens showed significant associations with a hospital stay longer than 28 days. As a result, PLA patients presenting with a low PWR were shown to have more complications and a poor prognosis. Considering its cost-effectiveness, PWR could be a novel biomarker used to predict a prognosis of PLA.

A rare Danish case of Yersinia pseudotuberculosis pyogenic liver abscess

Yersinia pseudotuberculosis is a rare Gram-negative bacillus that cause enterocolitis and terminal ileitis. We report the first Danish case with Y. pseudotuberculosis multiple pyogenic liver abscess presenting with 6 weeks intermittently fever, fatigue, and weight loss. The patient was successfully treated with percutaneous drainage and intravenous piperacillin/tazobactam and oral ciprofloxacin.

Clinical and genomic characterization of hypervirulent Klebsiella pneumoniae (hvKp) infections via passive surveillance in Southern California, 2020–2022

Hypervirulent Klebsiella pneumoniae (hvKp) is more invasive and virulent than classical K. pneumoniae, and requires specialized treatment. To raise clinical awareness, this study determined the prevalence, clinical characteristics, and genomic epidemiology of hvKp infections in Southern California (SoCal) by conducting a passive surveillance in a single large academic medical center. We report here that hvKp infections were more common than expected, accounting for 2.6% of invasive K. pneumoniae infections, and presented with a wide disease spectrum, occasionally mimicking tumors, even co-infecting a COVID-19 patient. Most infections were community acquired with no recent international travel, suggesting hvKp strains are circulating in the community. Genomic analysis revealed genetic diversity, with the K1-ST23 lineage predominating but not clonal, and multiple sequence types of K2 including a SoCal unique K2-ST66 sublineage that had been unrecognized. Our findings highlight the urgency of heightened awareness of hvKp infection in the US, the need for rapid diagnosis of hvKp, and the necessity of implementing robust surveillance programs for hvKp at the institutional or local level.

A wide clinical spectrum of pulmonary affection in subjects with community-acquired Klebsiella pneumoniae liver abscess (CA-KPLA)

BACKGROUND

Klebsiella pneumoniae is a major pathogen of bacterial liver abscess in Asia. Particularly, patients with community-acquired Klebsiella pneumoniae liver abscess (CA-KPLA) tend to have a higher risk of invasive infection and pulmonary is a common invasive infectious site, making it a global clinical crisis. Therefore, considerable attention should be focused on the early prediction and active treatment strategies of such patients.

METHODS

The clinical data of 127 CA-KPLA cases hospitalized from January 2017 to February 2022 were collected from a single center. Risk factors were analyzed by the use of univariable and multivariable analysis. Furthermore, independent risk factors of pulmonary affection were utilized to construct a predictive nomogram.

RESULTS

The incidence of pulmonary affection in KPLA patients was 57.5% (73/127) and the majority manifested as nodular lesions with cavities and pleural effusion in chest CT images. Based on the predictive nomogram, the SOFA score (>2) was defined as the most dominant independent risk factor for the occurrence of pulmonary affection, followed by the maximum diameter of liver abscess (>3 cm), multiple liver abscesses, bacteremia, and badly-controlled diabetes sequentially. The validation of this nomogram also demonstrated good discriminative ability and satisfactory consistency. Finally, early drainage of liver abscess, initial combinational antibiotics, and early Carbapenem-including antibiotic usage were established as favorable factors for therapy in pulmonary affected CA-KPLA patients.

CONCLUSION

This study provided an effective model for the early prediction of pulmonary affection in patients with CA-KPLA and some rational strategies for their early therapeutic remission.

Liver abscesses in the Western pediatric population

Background and study aims: Liver abscesses are rare in the Western pediatric population and data on predisposing factors and etiology are scarce. We aimed to describe predisposing factors, microbiological characteristics, and treatment. Patients and methods: Retrospective analysis of children admitted to two tertiary care hospitals in Belgium from 1 January 1996 to 31 December 2019. We analyzed clinical features, predisposing factors, imaging characteristics, microbiological data, treatment, and outcome in children with a liver abscess and compared these data with the literature. Results: We collected 24 cases with a male to female ratio of 1.4 and a median age of 3.2 years at time of diagnosis. Survival was 95.8%. Invasive culture specimens were obtained in 83.3% and showed growth of bacteria in 55%. Parenteral antibiotics were administered before invasive culture sampling in 80%. Liver abscesses were cryptogenic in four (16.7%) patients. Hepatobiliary disease was the most prevalent predisposing factor (n = 6; 25%), followed by recent antineoplastic therapy for malignancies (n = 5; 20.8%), intra-abdominal surgical pathology (n = 4; 16.7%) and umbilical venous catheters (n = 2; 8.3%). In two patients there was a parasitic origin (n = 2; 8.3%) and in one it was caused by Bartonellosis. There was no diagnosis of chronic granulomatous disease (CGD) in our cohort. Conclusions: Pediatric liver abscesses have a favorable outcome in the developed world. Whenever feasible, invasive abscess culture specimens should be obtained. In patients presenting with a cryptogenic liver abscess or atypical disease course, immunological workup should be ensured.

Demographics, Radiological Findings, and Clinical Outcomes of Klebsiella pneumonia vs. Non-Klebsiella pneumoniae Pyogenic Liver Abscess: A Systematic Review and Meta-Analysis with Trial Sequential Analysis

Pyogenic liver abscess (PLA) is a common cause of hepatobiliary sepsis. Klebsiella pneumoniae (KP) is the most common organism causing PLA. Evidence is scarce on the demographics, radiological findings, and outcomes of KPPLA versus non-KPPLA (N-KPPLA). PubMed, Embase, The Cochrane Library, and Scopus were systematically searched until 14 May 2022 for studies comparing KPPLA and N-KPPLA. Exclusion criteria were single-arm studies. Primary outcomes were mortality (30-day/in-hospital) and metastatic complications. There were 16 studies, including 5127 patients (KPPLA n = 3305, N-KPPLA n = 1822). Patients with KPPLA were younger (mean difference: −2.04 years, p = 0.02). History of hepatobiliary disease (Odds ratio (OR) 0.30, 95% CI: 0.20, 0.46) and malignancy (OR 0.26, 95% CI: 0.16, 0.42) were less common in KPPLA. KPPLA was associated with lower incidence of multiple abscesses (OR 0.52, 95% CI: 0.35, 0.76, p < 0.001) and bilobar abscesses (OR 0.60, 95% CI: 0.49, 0.74, p < 0.001). KPPLA has higher overall metastatic complications (KPPLA 9.7% vs. N-KPPLA 4.8%, OR 3.16, 95% CI: 2.00, 4.99, p < 0.001), but lower mortality (KPPLA 3.9% vs. N-KPPLA 7.6%, OR 0.51, 95% CI: 0.34, 0.78, p < 0.001). Trial sequential analysis showed conclusive evidence that KPPLA has lower mortality than N-KPPLA. In conclusion, KPPLA has lower mortality than N-KPPLA.

Emergence of K1 ST23 and K2 ST65 hypervirulent klebsiella pneumoniae as true pathogens with specific virulence genes in cryptogenic pyogenic liver abscesses Shiraz Iran

Hypervirulent Klebsiella pneumoniae (hvKp) pathotype is emerging worldwide in pyogenic liver abscesses (PLAs). However, the role of virulence factors in pathogenicity remains unclear. On the other hand, the epidemiology of PLAs in Iran is unknown. From July 2020 to April 2022, bacterial species were isolated and identified from the drainage samples of 54 patients with PLAs. K. pneumoniae as the most common pathogen of pyogenic liver abscesses was identified in 20 (37%) of the 54 patients. We analyzed the clinical and microbiological characteristics of K. pneumoniae-related pyogenic liver abscesses. Antibiotic susceptibility testes and string test were performed. 16S rRNA, antibiotic resistance, and virulence genes were determined by polymerase chain reaction amplification. Clonal relatedness of isolates was identified by multilocus sequence typing. Virulence levels were assessed in the Galleria mellonella larval infection model. Four hvKp isolates (K1/K2) were found to be responsible for cryptogenic PLAs, and 16 classical K. pneumoniae isolates (non-K1/K2) were associated with non-cryptogenic PLAs. Three capsular serotype K1 strains belonged to sequence type 23 (ST23) and one K2 strain to ST65. Meanwhile, the non-K1/K2 strains belonged to other STs. ST231 was the most common strain among the classical K. pneumoniae strains. Compared with the non-K1/K2 strains, capsular serotypes K1/K2 strains were less resistant to antibiotics, had positive string test results, and had more virulence genes. In Galleria mellonella, a concentration of 10⁶ colony-forming units of the K1 hvKp strain resulted in 100% death at 24 hours, confirming the higher virulence of the hvKp strain compared with cKp. K. pneumoniae isolates represented that the acquisition of any plasmid or chromosomal virulence genes contributes to pathogenicity and high prevalence in PLAs. Meanwhile, hvKp isolates with a specific genetic background were detected in cryptogenic PLAs.

Characteristics of Computed Tomography for Identifying Patients at High Risk of Endogenous Endophthalmitis Due to Klebsiella pneumoniae-Related Pyogenic Liver Abscess

Endogenous endophthalmitis (EE) associated with Klebsiella pneumoniae (K. pneumoniae)-related pyogenic liver abscess (PLA) is one of the fatal complications of PLA and leads to loss of vision. Early diagnosis and treatment are important to save the patient’s vision. We investigated the characteristics of computed tomography (CT) in EE associated with K. pneumoniae-related PLA for the identification of the predictors of EE, in order to facilitate early diagnosis. A total of 274 patients diagnosed with K. pneumoniae-related PLA, including 15 patients with EE, were identified between January 2005 and December 2019. The clinical (age, gender, and underlying disease) and radiologic (the location, size, and number of abscesses) features were reviewed. In addition, the involvement of the adjacent vessels, such as the hepatic vein and portal vein, was carefully reviewed. A comparative analysis was performed between the EE and non-EE groups. Uni- and multivariate logistic regression analyses were used to identify the predictors of EE. Diabetes mellitus (DM), the involvement of the left or both hepatic lobes, and the adjacent vessels on the CT were significantly more frequent than those in the non-EE group (p < 0.05 in all), and they were the significant predictors of EE in the logistic regression analyses. In patients with K. pneumoniae-related PLA, the CT findings, such as the locations of the abscess (i.e., left or both lobes) and the involvement of the adjacent vessels, should be considered in addition to the ocular symptoms for an early diagnosis of EE.

Development of Klebsiella pneumoniae Capsule Polysaccharide-Conjugated Vaccine Candidates Using Phage Depolymerases

Klebsiella pneumoniae is an important pathogen associated with nosocomial infection and has developed increasing resistance to antibiotics such as extended-spectrum β-lactams and carbapenem. In recent years, K. pneumoniae isolates have emerged as a major cause of global community-acquired infections such as pneumonia and pyogenic liver abscess. Although serotypes K1 and K2 have been identified as the predominant capsular types associated with invasive infections, no K. pneumoniae vaccine is commercially available, probably due to immunogenicity loss in the traditional depolymerization method to obtain capsule polysaccharide (CPS) for the preparation of conjugated vaccine. In this study, we successfully retained immunogenicity by using K1 (K1-ORF34) and K2 (K2-ORF16) CPS depolymerases that were identified from phages to cleave K1 and K2 CPSs into intact structural units of oligosaccharides with intact modifications. The obtained K1 and K2 oligosaccharides were separately conjugated with CRM197 carrier protein to generate CPS-conjugated vaccines. Immunization experiments of mice showed both K1 and K2 CPS-conjugated vaccines induced anti-CPS antibodies with 128-fold and 64-fold increases of bactericidal activities, respectively, compare to mice without vaccinations. Challenge tests indicated that K1 or K2 CPS-conjugated vaccine and divalent vaccine (a mixture of K1 and K2 CPS-conjugated vaccines) protected mice from subsequent infection of K. pneumoniae by the respective capsular type. Thus, we demonstrated K1 and K2 CPS-conjugated vaccines prepared by CPS depolymerases is a promising candidate for developing vaccines against human K. pneumoniae infections.

Multicenter Surveillance of Capsular Serotypes, Virulence Genes, and Antimicrobial Susceptibilities of Klebsiella pneumoniae Causing Bacteremia in Taiwan, 2017–2019

We conducted a longitudinal epidemiological surveillance of hypervirulent Klebsiella pneumoniae (hvKP) in Taiwan. Bacteremic KP isolates collected from 16 hospitals in Taiwan between 2017 and 2019 were collected, and the virulent serotypes (K1, K2, K20, K54, and K57), antimicrobial susceptibilities, and virulence genes of these isolates were investigated. During the 3-year period, 1,310 bacteremic KP isolates were collected, of which 27.5% belonged to virulent serotypes, including K1 (n = 162), K2 (n = 74), K57 (n = 56), K54 (n = 41), and K20 (n = 27). K1 was the most prevalent capsular serotype, with an annual prevalence of 11–15%, and was equally distributed across the four geographic areas. The prevalence of K2 declined significantly in 2019. According to wzi-K typing results, 87% of K1 isolates were classified as wzi-1. Among K2 isolates, wzi-72 (55.4%) and wzi-2 (41.9%) were the most common, whereas wzi-206 was the most prevalent (48.2%) among K57 isolates, followed by wzi-77 (25.0%). Wzi-115 accounted for 85.4% of the K54 isolates, whereas wzi-95 accounted for 92.6% of K20 isolates. rmpA was present in 99.4% of K1, 98.6% of K2, 89.3% of K57, 78.0% of K54, and 84.0% of K20 isolates. rmpA2 was present in 100% of K1 and 98.6% of K2 isolates but was only present in 64.3% of K57, 58.5% of K54, and 74.1% of K20 isolates. K1 remains the dominant hvKP serotype and is associated with most virulence genes in Taiwan. Further studies are required to elucidate the significance of other virulent serotypes.

[Bacterial hepatobiliary infections : Pathogen spectrum, antimicrobial resistance and current treatment concepts]

Ascending cholangitis and pyogenic liver abscesses are acute febrile bacterial hepatobiliary diseases. Nowadays they frequently occur in patients with structural changes of the biliary system and are usually treated by a combination of interventional drainage procedures and antimicrobial therapy. While Gram-negative Enterobacterales were identified as major causes in the past, biliary tract interventions and antibiotic exposure have contributed to an increase in enterococcal species and extended spectrum beta-lactamase (ESBL)-producing Enterobacterales. When selecting an appropriate empirical treatment the treating internist must consider local and individual risk factors for antimicrobial resistance in addition to pharmacokinetic aspects and disease severity to reduce the likelihood of treatment failure.

A Case of Chorioretinitis with Retinal Angiomatous Proliferation

A 48-year-old woman had an acute blurred vision in the right eye immediately after drainage of liver abscess. Her best corrected visual acuity (BCVA) was 8/400; fundus photography suggested the diagnosis of endogenous endophthalmitis with chorioretinitis and vitritis. Due to the bad systemic condition, a systemic antibiotic combined with periocular triamcinolone (TA) was carried out first. Inflammatory cells in the vitreous cavity were decreased after treatment; however, fundus fluorescein angiography (FFA) showed abnormal dilation and leakage of the capillaries and retinal-choroidal anastomose, supporting that there was retinal angiomatous proliferation (RAP). Vitreous interleukin-6 (IL-6) was only slightly elevated; the ratio of interleukin-10 (IL-10) and IL-6 was less than 1, and the etiological test was negative. After receiving intravitreal vancomycin injection combined with periocular TA injection, the patient's BCVA was improved from 16/400 to 20/400 with a reduction in vitreous inflammatory cells. However, the patient's RAP was progressed and her BCVA was dramatically decreased to count finger/30 cm. After intravitreal injection of ranibizumab, the patient's BCVA was 5/400 with a significant shrink in lesions and absorption of hemorrhage, exudation, and fluid. Thus, we suggest that early anti-inflammatory treatment in conjunction with anti-VEGF may achieve a better prognosis in patients with inflammatory retinal angiomatous proliferation (RAP).

Clinical characteristics and outcome of patients with enterococcal liver abscess

Epidemiology of bacteria isolated from pyogenic liver abscesses change, and an increase in enterococci has been reported in European hospitals. The aim of this study was to investigate the clinical characteristics and outcome of enterococcal PLA. We performed a retrospective analysis of patients with microbiologically confirmed PLA at three German university centers. Indicators of enterococcal PLA were determined using binary logistic regression, and survival analysis was performed using Kaplan-Meier statistics and Cox regression analysis. Enterococci were isolated in 51/133 (38%) patients with PLA. Patients with enterococcal PLA had smaller abscess diameter (4.8 vs. 6.7 cm, p = 0.03) than patients with non-enterococcal PLA, but had more frequent polymicrobial culture results. In univariate logistic regression analysis, alcohol abuse (OR 3.94, 95% CI 1.24-12.49, p = 0.02), hepatobiliary malignancies (OR 3.90, 95% CI 1.86-8.18, p < 0.001) and cirrhosis (OR 6.36, 95% CI 1.27-31.96, p = 0.02) were associated with enterococcal PLA. Patients with enterococcal PLA had a higher mortality than patients with non-enterococcal PLA (hazard ratio 2.92; 95% confidence interval 1.09-7.80; p = 0.03), which remained elevated even after excluding patients with hepatobiliary malignancies, cirrhosis, and transplant recipients in a sensitivity analysis. The increased mortality was associated with non-fecal enterococci but not in patients with Enterococcus faecalis. In this retrospective, multicenter study, enterococcal PLA was common and indicated an increased risk of mortality, underscoring the need for close clinical monitoring and appropriate treatment protocols in these patients.

The molecular characteristics, clinical manifestations, 44 and risk factors of hypervirulent Klebsiella pneumoniae infections in a large teaching hospital in southwest China

Hypervirulent Klebsiella pneumoniae (hvKp) has been globally disseminated recently, especially in Asia. The purpose of this study was to identify the molecular characteristics, clinical manifestations, and clinical risk factors of hvKp infections among patients in a large teaching hospital. A retrospective study was conducted in 123 patients infected with K. pneumoniae at the Affiliated Hospital of Southwest Medical University (Luzhou, China) from October 2016 to November 2018. An isolate that positive for both PCR amplification of aerobactin gene and Galleria mellonella infection model was defined as hvKp. Overall, 43.1% (53/123) of K. pneumoniae isolates were hvKp. String tests were performed on all isolates, and MLSTs of all hvKp were conducted. The K1 ST23 isolates were the dominant clone of hvKp (35.8%). Univariate analysis revealed the following risk factors for hvKp: hepatic abscess (OR = 41.818 [95% CI, 5.379-335.086]), bacteremia (OR = 19.94 [95% CI, 5.565-71.446]), metastatic spread (OR = 19.938 [95% CI, 6.344-62.654]), CRP (OR = 1.008 [95% CI, 1.001-1.015]), nitroimidazole treatment (OR = 7.907 [95% CI, 1.652-37.843]), diabetes (OR = 3.067 [95% CI, 1.38-6.817]), and admission to positive culture interval (OR = 3.636 [95% CI, 1.524-8.678]). Moreover, Multivariate analysis implicated hepatic abscess (OR = 74.332 [95% CI, 3.121-1769.588]), bacteremia (OR = 28.388 [95% CI, 3.039-264.200]), and metastatic spread (OR = 19.391 [95% CI, 3.633-103.498]) as independent risk factors for hvKp infections. Thirteen of twenty-one tested antibiotics were founded resistance to non-hvKp, which is significantly greater than hvKp. Importantly, the ESBL-hvKp and MDR-hvKp were responsible for 7.5% and 15.1% in the hvKp group, respectively.

A population-based study of pyogenic liver abscess in Korea: Incidence, mortality and temporal trends during 2007-2017

BACKGROUND/AIMS

Although the epidemiology of pyogenic liver abscess (PLA) continues to change, only a few population-based studies have been conducted in Korea. This study investigated the epidemiology and clinical outcomes of PLA patients during a period of 10 years.

METHODS

We analysed the Health Insurance Review and Assessment Service data between 2007 and 2017. The data included annual incidence rates, demographic data, underlying diseases, complications and mortality of PLA patients.

RESULTS

The annual incidence of PLA for all age groups was 10.9 per 100 000 population. The incidence was gradually increased from 5.7 per 100 000 in 2007 to 14.4 per 100 000 in 2017. In patients with liver abscess, the prevalence of diabetes and malignancy were 37.24% and 26.5% respectively. Metastatic infection was reported in 1.74% of the patients, and endophthalmitis was most common. The mean in-hospital mortality was 9.6%, and there was no significant difference in mortality by year during the observation period. Mortality increased with age and was greatly affected by the underlying diseases, especially cancer. Based on the multivariate analysis results, the mortality of PLA patients was associated with older age, female sex, diabetes, malignancy and chronic kidney disease.

CONCLUSION

The PLA incidence is rapidly increasing in Korea, especially in people with comorbidities. In addition, the causes and risk factors of PLA infections are changing and thus further research on epidemiology, different diagnosis and management approaches is required.

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

Background

Few studies have studied the relationship between blood culture and mortality in sepsis patients. The aim of this study was to compare the characteristics and outcomes of positive and negative blood culture sepsis.

Methods

We performed a study on 640 patients suffering from sepsis in Beijing Chao-Yang Hospital from October 2017 to December 2019. The primary findings revolved around length and expenditure of hospital stay, the possibility of suffering from acute respiratory distress syndrome (ARDS), and any requirements for mechanical ventilation. The secondary findings revolved around whether the patient died early (28-day) or late (28-to-90-day).

Results

A total of 592 of the 640 patients met the inclusion criteria for sepsis, with 274 of them having culture-positive results. The culture-positive patients were mostly elderly suffering from diabetes and at risk of cancer, with a higher white blood cell count, and higher procalcitonin. Additionally, they scored higher in their acute physiology and chronic health evaluation II score (15 vs.11, P=0.010), as well as in their predisposition, infection, response, and organ dysfunction (17 vs 11, P<0.001) than the individuals in the culture-negative group. Culture-positive patients had a longer duration of hospital stay (14 vs 6, P<0.001) and higher in-hospital mortality (14.6% vs 8.5%, P=0.019) than culture-negative ones. No significant difference in intensive care unit (ICU) mortality (45.7% vs.36.4%, P=0.254) or early mortality (9.5% vs 7.2%, P=0.321) was noted between the two groups. However, the culture-positive patients had increased late mortality (15.7% vs.6.9%, P=0.001), when compared with those with culture-negative results in the cohort. Furthermore, the culture-positive patients who received the appropriate antibiotics early had a lower mortality rate than the culture-negative patients (7.3% vs.14.2%, P=0.008).

Conclusion

Culture-positive patients had higher in-hospital mortality, comparable early mortality, and worse late mortality than the culture-negative patients. Early appropriate use of antibiotics might reduce mortality and improve clinical prognosis.

Clinical comparison of febrile and afebrile patients with pyogenic liver abscess: A two-centre retrospective study

BACKGROUND

: Limited research has been conducted on afebrile pyogenic liver abscess (PLA). This poses a challenge in rapid diagnosis and early tailored care to physicians. In his study, we aimed to compare the clinical characteristics of afebrile and febrile patients with PLA.

METHODS

: We retrospectively analyzed the data of patients with PLA who were admitted to the emergency departments of two university hospitals between January 2014 and March 2020. Patients were classified into afebrile and febrile groups by using body temperature higher than 38°C as the reference standard. The demographic, clinical, and laboratory characteristics of both groups were compared. The primary outcome was all-cause in-hospital mortality and length of hospital stay. Multivariate analysis was performed to define factors associated with afebrile PLA.

RESULTS

: Of the 239 patients included in this study, 51 patients (21.3%) were afebrile and 188 patients (78.7%) were febrile. There were no differences between the abscess characteristics, laboratory manifestations, and disease severity of both groups; however, age and Charlson score differed between the groups (P = 0.009 and P = 0.011). The all-cause in-hospital mortality rate was much higher in the afebrile PLA group than in the febrile PLA group (9.8% vs. 2.1%, P = 0.011). Regarding the length of stay, no significant differences were noted in the febrile PLA group compared with the afebrile PLA group (18.5% vs 17.3%, P = 0.514). In multivariate analyses, only age greater than 65 years was significantly associated with afebrile PLA.

CONCLUSIONS

: Afebrile patients with PLA tend to be older, have higher Charlson scores, and in-hospital mortality rate than those with febrile patients. PLA patients older than 65 years are more likely to present without fever (<38°C) at the time of the emergency visit.

Bleeding risk of image-guided percutaneous catheter drainage of pyogenic liver abscess in patients with coagulopathy

OBJECTIVE

Percutaneous catheter drainage (PCD) is the mainstream treatment for pyogenic liver abscess (PLA). However, in some patients with severe coagulopathy, there may increase the risk of bleeding complications related to PCD. Therefore, this study was aimed to evaluate the incidence of bleeding complications of PCD in PLA patients complicated with coagulopathy.

METHODS

Between January 2011 and September 2019, patients diagnosed with PLA who had undergone PCD were selected retrospectively. Based on the preoperative coagulation parameters, the patients were divided into the coagulopathy group (PLT ≤ 50 × 10⁹/L or INR ≥ 1.5) and the normal coagulation group. The major and minor bleeding complications related to PCD were compared between the two groups. The ICU occupancy and mortality rates in the coagulopathy group were assessed and compared with patients of normal coagulation group.

RESULTS

A total of 583 PLA patients subjected to PCD were selected. 522 patients were finally included in this study: 64 cases (12.26%) in the coagulopathy group and 458 cases (87.74%) in the normal coagulation group. No major bleeding complications related to PCD was observed. Two patients (0.38%) of minor bleeding complications, one patient in each group, showed no statistically significant difference (0.2% vs.1.6%, P > 0.05). The ICU occupancy rate of coagulopathy group was significantly higher than normal coagulation group (6.2% vs. 0.7%, P < 0.05). No significant difference in mortality rate was noted between the two groups (4.7% vs.1.5%, P > 0.05).

CONCLUSION

The incidence of bleeding complications related to PCD in PLA patients is rare even if complicated with coagulopathy.