Clinical and CT comparative study of invasive and non-invasive Klebsiella pneumoniae liver abscesses.

AIM: To investigate the clinical and CT features of invasive and non-invasive Klebsiella pneumoniae liver abscesses (KPLA). MATERIALS AND METHODS: Fifty-one patients with KPLA diagnosis including 26 invasive and 25 non-invasive KPLA cases were analysed retrospectively. All patients underwent routine abdominal unenhanced and three-phase enhanced CT examinations. The CT images were assessed by two experienced radiologists by examining location, number, size, septa, texture, gas in the pus cavity, portal phlebitis, thrombophlebitis, and abnormal perfusion during the arterial phase. Statistical differences for continuous characteristics were analysed with independent samples t-test or Wilcoxon's test, while the chi-square test or Fisher's exact test was used for categorical variables. A logistic regression analysis was performed to determine the independent related factors of invasive KPLA and receiver operating characteristic (ROC) curves were used for assessment. RESULTS: Age and type 2 diabetes were significantly different between the patients with invasive and non-invasive KPLA. In addition, patients with invasive KPLA had lower levels of platelet and total protein (p<0.05) and higher total bilirubin compared to patients with non-invasive KPLA. Throughout the regression analysis, total bilirubin, platelets, and total protein demonstrated an area under the ROC curves of 0.717, 0.745, and 0.728, respectively. CONCLUSION: Invasive KPLA occurs predominantly in younger patients with type 2 diabetes. Laboratory tests revealed low platelet and total protein levels and high total bilirubin levels. If the patient with KPLA exhibits hepatic venous thrombophlebitis with no abnormal enhancement around the abscess in the arterial phase of enhanced CT, it indicates that the abscess has invaded.

Development and validation of a prediction model based on clinical and CT features for invasiveness of K. pneumoniae liver abscess.

OBJECTIVES: Klebsiella pneumoniae liver abscess (KPLA) complicated with extrahepatic migratory infection (EMI) is defined as invasive KPLA. The current study aimed to develop and validate a risk prediction model for the invasiveness of KPLA. METHODS: From 2010 to 2020, KPLA patients from four institutes were selected retrospectively. In the development cohort, risk factors from a logistic regression analysis were utilized to develop the prediction model. External validation was performed using an independent cohort. RESULTS: A total of 382 KPLA patients comprised two separate cohorts: development cohort (institute 1, n = 286) and validation cohort (institute 2-4, n = 86). The overall incidence of EMI was 19.1% (development cohort, n = 55; validation cohort, n = 18, p > 0.05). In the development cohort, four risk factors (age ≤ 40 years, fasting blood glucose (FBG) > 7 mmol/L, no rim enhancement, and thrombophlebitis on CT), significantly associated with EMI, were incorporated into the scoring system. The area under curve (AUC) of the receiver operating characteristic curve (ROC) in the development and validation cohorts was 0.931 (95% confidence interval [CI]: 0.93-0.95) and 0.831 (95% CI: 0.86-0.91), respectively. The calibration curves fitted well. The incidence of EMI was 3.3% and 56.5% for the low- (total scores ≤ 4) and high-risk (total scores > 4) groups in the development cohort, and 3.2% and 66.7% in the validation cohort (all p < 0.001), respectively. CONCLUSIONS: Age ≤ 40 years, FBG > 7 mmol/L, no rim enhancement, and thrombophlebitis were independent risk factors for EMI. This validated prediction model may aid clinicians in identifying KPLA patients at increased risk for invasiveness. KEY POINTS: • Four risk factors are significantly associated with extrahepatic migratory infections (EMI): age ≤ 40 years, fasting blood glucose (FBG) > 7 mmol/L, no rim enhancement, and thrombophlebitis on CT. • Based on these risk factors, the current study developed and validated a prediction model for the invasiveness of Klebsiella pneumoniae liver abscess (KPLA). • This validated prediction model may in the help early identification of KPLA patients at increased risk for invasiveness.

Clinical and computed tomography features of extended-spectrum ß-lactamase-producing Klebsiella pneumoniae liver abscess.

BACKGROUND: Klebsiella pneumoniae (KP) is the primary pathogen associated with pyogenic liver abscesses (PLAs). Moreover, there has been an increase in the proportion of extended-spectrum beta-lactamase (ESBL)-producing KP. However, the clinical and computed tomography (CT) features of liver abscesses caused by ESBL-producing KP have not been separately described. We aimed to compare the clinical and CT features present in patients with ESBL-producing and non-ESBL-producing KP as well as to determine the risk factors for ESBL-producing KP liver abscesses (KPLAs). METHODS: We performed a retrospective analysis of data obtained from the medical records of patients with a first episode of KPLA admitted to Shengjing Hospital of China Medical University between May 2015 and May 2019. We compared the clinical and CT features between patients with ESBL-producing and non-ESBL-producing KPLA. RESULTS: We enrolled 100 patients with KPLA (14 and 86 in the ESBL-producing and non-ESBL-producing groups, respectively). There was no significant between-group difference in the proportion of patients with comorbid diabetes (71.43% vs. 66.2%, p = 0.086). The ESBL-producing KPLA group had a greater proportion of patients with a history of biliary disease (78.57% vs. 26.74%, p < 0.001) and gastrointestinal malignancy (50% vs. 6.98%, p < 0.001). Multivariate regression analysis showed that a history of biliary disease was an independent risk factor for ESBL-producing KPLA. Compared with the non-ESBL-producing KPLA group, the ESBL-producing KPLA group had a significantly higher intensive care unit (ICU) admission rate (28.57% vs. 2.33%, p < 0.001). All ESBL-producing KP isolates were susceptible to carbapenems and amikacin. Only the presence of multiloculation on CT was found to be significantly different between the groups (50% vs. 82.56%, p = 0.012). CONCLUSIONS: The presence of biliary disease was an independent risk factor for ESBL-producing KPLA. Patients with ESBL-producing KPLA had a higher ICU admission rate, with only half of patients having evidence of multiloculation on CT.

Contrast-Enhanced Ultrasound Appearance of Hypervirulent Klebsiella pneumoniae Liver Abscesses.

There has been a paradigm shift with Klebsiella pneumoniae (KP) emerging as the most frequently isolated bacterium in pyogenic liver abscesses in immunocompetent patients. Colonization of this hypervirulent KP strain has led to community-acquired liver abscesses. Septic seeding to distant sites of the body has been recognized and is strongly associated with diabetes. Contrast-enhanced computed tomographic features have been described. Grayscale ultrasound (US) features remain inconclusive, with variable US appearances. Here we describe the contrast-enhanced US features of KP liver abscesses, which correlated with previously described computed tomographic findings. The use of contrast-enhanced US eliminates the need for radiation exposure.

A case of Klebsiella pneumoniae spondylitis and bacteremia potentially due to inflammation around a fecalith.

We herein report a case of Klebsiella pneumoniae (K. pneumoniae) spondylitis and bacteremia in a 90-year-old man with diabetes mellitus who had undergone sigmoidectomy and had a fecalith. Two months prior to admission, he had received antimicrobial treatment for 2 weeks for K. pneumoniae bacteremia whose entry was unclear and he was readmitted to our hospital owing to fever and stomachache. K. pneumoniae was isolated from two sets of blood cultures, and computed tomography and magnetic resonance imaging revealed inflammation and destruction of the 8th and 9th thoracic vertebra. The diagnosis was spondylodiscitis secondary to K. pneumoniae bacteremia. Although the entry point for K. pneumoniae was unclear, we suggest that inflammation of the mucosa around the fecalith might have caused the Enterobacteriaceae bacteremia.

[Endogenous Klebsiella pneumoniae endophthalmitis associated with Klebsiella pneumoniae pneumonia: 3 cases report and literature review].

Objective: To study the clinical features and the diagnosis and treatment of endogenous Klebsiella pneumoniae endophthalmitis associated with Klebsiella pneumoniae pneumonia. Methods: Three cases of endogenous Klebsiella pneumoniae endophthalmitis associated with Klebsiella pneumoniae with microbiological evidence were studied. The related literatures published from January 2008 to June 2018 were reviewed with "pneumonia" , "endogenous endophthalmitis" and "Klebsiella pneumoniae" as the keywords in CNKI, Wanfang, PubMed and Web of Science databases. Results: The 3 patients, all males, aged 54 years, 82 years and 48 years respectively. They all had a history of type 2 diabetes mellitus. Endophthalmitis occurred in one eye in all of them, and the patients had eye symptoms including eye pain, progressive loss of vision, periorbital area inflammation, conjunctivitis, weakening or disappearance of pupil light reflex, corneal edema and anterior chamber effusion. All of 3 cases had multiple patchy pulmonary lesions, and Klebsiella pneumoniae was proven to be the pathogen by blood culture. Two cases had pulmonary abscess and liver abscess, and one of them had brain abscess. A total of 28 literatures with 81 cases of endogenous Klebsiella pneumoniae endophthalmitis associated with Klebsiella pneumoniae pneumonia were retrieved from CNKI, WanFang, PubMed and Web of Science database. Conclusions: Klebsiella pneumoniae was one of the most common pathogens of pneumonia and endogenous endophthalmitis, which would seriously damage the lung and the eye. The early clinical features were not specific. Misdiagnosis or missed diagnosis might cause serious consequences. Eye pain and visual disturbance symptoms, ophthalmic examination, chest imaging, blood and aqueous humor etiology were of great value in the diagnosis of this disease.

Core curriculum illustration: acute pyelonephritis.

This is the 26th installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online please visit the ASER Core Curriculum and Recommendations for Study online at: http://www.aseronline.org/curriculum/toc.htm .

Computed Tomography Features of Septic Pulmonary Embolism Caused by Klebsiella pneumoniae Liver Abscess Associated With Extrapulmonary Metastatic Infection.

OBJECTIVES: The aims of the study were to investigate the computed tomography (CT) features and clinical course of septic pulmonary embolism (SPE) caused by Klebsiella pneumoniae liver abscess (KPLA) and to explore the possible mechanism underlying the spread of infection. METHODS: Twenty-one patients with KPLA-induced SPE admitted to our hospital between January 2010 and May 2015 were evaluated. According to the presence or absence of extrapulmonary metastatic infection (EMI), they were divided into EMI and non-EMI groups and clinical and CT features of the 2 groups were compared. Hepatic vein thrombophlebitis was evaluated on liver CT images. Chest CT features included nodules, wedge-shaped lesions, ground-glass opacity, consolidation, cavitation, feeding vessel sign, pleural effusion, and lymphadenopathy. RESULTS: All the vessels within the so-called feeding vessel sign were confirmed as pulmonary veins by multiplanar reconstruction, so we used an alternative name draining vessel sign (DVS) instead. Peripheral nodules, DVS, and consolidation were the main CT features of KPLA-induced SPE. Peripheral nodules and DVS were more frequently seen in the EMI group than in the non-EMI group (P = 0.019 and 0.008, respectively). Five of 8 patients with hepatic vein thrombophlebitis had lung consolidation, whereas only 3 of 13 patients without hepatic vein thrombophlebitis had lung consolidation, although the difference was not significant (P = 0.09). CONCLUSIONS: Multiple pulmonary nodules and DVS were associated with EMI. Hepatic and pulmonary vein invasion are possible causes underlying the metastatic spread of infection.

Development of a Hybrid Tracer for SPECT and Optical Imaging of Bacterial Infections.

In trauma and orthopedic surgery, infection of implants has a major impact on the outcome for patients. Infections may develop either during the initial implantation or during the lifetime of an implant. Both infections, as well as aseptic loosening of the implant, are reasons for revision of the implants. Therefore, discrimination between aseptic-mechanical-loosening and septic-bacterial-loosening of implants is critical during selection of a patient-tailored treatment policy. Specific detection and visualization of infections is a challenge because it is difficult to discriminate infections from inflammation. An imaging tracer that facilitates bacterial identification in a pre- and intraoperative setting may aid the workup for patients suspicious of bacterial infections. In this study we evaluated an antimicrobial peptide conjugated to a hybrid label, which contains both a radioisotope and a fluorescent dye. After synthesis of DTPA-Cy5-UBI29-41 and-when necessary-radiolabeling with (111)In (yield 96.3 ± 2.7%), in vitro binding to various bacterial strains was evaluated using radioactivity counting and confocal fluorescence microscopy. Intramuscular bacterial infections (S. aureus or K. pneumoniae) were also visualized in vivo using a combined nuclear and fluorescence imaging system. The indium-111 was chosen as label as it has a well-defined coordination chemistry, and in pilot studies labeling DTPA-Cy5-UBI29-41 with technetium-99m, we encountered damage to the Cy5 dye after the reduction with SnCl2. As a reference, we used the validated tracer (99m)Tc-UBI29-41. Fast renal excretion of (111)In-DTPA-Cy5-UBI29-41 was observed. Target to nontarget (T/NT) ratios were highest at 2 h post injection: radioactivity counting yielded T/NT ratios of 2.82 ± 0.32 for S. aureus and 2.37 ± 0.05 for K. pneumoniae. Comparable T/NT ratios with fluorescence imaging of 2.38 ± 0.09 for S. aureus and 3.55 ± 0.31 for K. pneumoniae were calculated. Ex vivo confocal microscopy of excised infected tissues showed specific binding of the tracer to bacteria. Using a combination of nuclear and fluorescence imaging techniques, the hybrid antimicrobial peptide conjugate DTPA-Cy5-UBI29-41 was shown to specifically accumulate in bacterial infections. This hybrid tracer may facilitate integration of noninvasive identification of infections and their extent as well as real-time fluorescence guidance during surgical resection of infected areas.

The association of haemoglobin A1C levels with the clinical and CT characteristics of Klebsiella pneumoniae liver abscesses in patients with diabetes mellitus.

OBJECTIVES: To compare the characteristics of Klebsiella pneumoniae liver abscesses (KPLA) in diabetic patients with different levels of glycaemic control. METHODS: The institutional review board approved this retrospective study. A total of 221 patients with KPLA were included. Clinical features of KPLA were compared. We divided the 120 diabetic patients with KPLA into three subgroups based on haemoglobin A1C (HbA1C) concentration (good, HbA1C ≤ 7.0 %; suboptimal, 7.0 % < HbA1C ≤ 9.0 %; poor, HbA1C > 9.0 %). In this study, we used a semiautomated quantitative method to assess the gas and total abscess volumes in KPLA. Statistical analysis was performed with the chi-squared test and one-way analysis of variance. RESULTS: The mortality rate did not significantly differ between the nondiabetic and diabetic groups. However, patients with poor glycaemic control had significantly more complications and therefore a longer hospital stay (P < 0.05). In our study, CT and quantitative analyses found that patients in the group with poor glycaemic control had a significantly higher incidence of gas formation and hepatic venous thrombophlebitis and a higher gas-to-abscess volume ratio than patients with suboptimal and good glycaemic control (P < 0.05). CONCLUSIONS: Diabetic patients with a high HbA1C concentration (>9.0 %) have an association with hepatic venous thrombophlebitis, gas formation and metastatic infection complications associated with KPLA. KEY POINTS: • Poorly controlled diabetes is associated with complications in Klebsiella pneumoniae liver abscesses. • Hepatic venous thrombosis and gas are important signs of metastatic infection. • Hepatic venous thrombophlebitis is associated with 72.7 % of metastatic infections.

Endogenous Klebsiella pneumoniae endophthalmitis.

Klebsiella pneumonia is a common human pathogen, and endogenous endophthalmitis is a vision-threatening infection presentedwith pain, redness, decreased vision acuity, and intraocular inflammation. Endogenous endophthalmitis caused by Klebsiella pneumoniae is uncommon and usually happens in patients with immunosuppression conditions. Diabetes is a predisposing risk factor, and liver abscess is a major source of Klebsiella pneumonia endogenous endophthalmitis (KPEE). Here, we report a case of KPEE in a patient who lost his vision in one eye after treatment.

Parotid abscess: a retrospective study of 14 cases at a regional hospital in Taiwan.

PROBLEM/OBJECTIVE: Acute suppurative sialadenitis commonly affects the parotid gland. However, acute suppurative parotitis with abscess formation is less common and possibly complicated by deep neck space infection and sepsis. Our aim was to analyze the clinical features, radiological findings, treatment modalities, and microbiology of parotid abscesses treated at a regional hospital in Taiwan over a 15-year period. METHODS: Records from patients diagnosed with acute suppurative parotitis or parotid abscesses between January 1998 and December 2012 were retrospectively reviewed. Parotid abscesses were confirmed by computed tomography (CT) examinations. RESULTS: Fourteen patients (9 males; mean age+standard deviation, 49.6 +/- 14.4 [range, 22-75] years) with parotid abscesses were included. Painful swelling at the angle of the jaw was the most common symptom. All patients sustained unilateral parotid abscesses, with left-sided lesions in 10 patients, and right-sided ones in 4 patients. Radiographically, 13 of 14 abscess lesions were located in the superficial lobe, and 1 was in the deep lobe of the parotid gland. Besides sufficient fluid hydration, maintenance of good oral hygiene, and administration of parenteral antibiotics, all patients were treated with surgical incision and drainage. Klebsiella pneumoniae was the organism most commonly isolated from abscess cultures. CONCLUSIONS: Parotid abscesses were found in about one fifth of patients with acute infectious parotid disease. Parenteral antibiotics plus surgical incision and drainage was the treatment of choice.

Development and validation of a clinical-radiomics nomogram for the early prediction of Klebsiella pneumoniae liver abscess.

BACKGROUND AND AIM: Pyogenic liver abscess (PLA) is a devastating and potentially life-threatening disease globally, with Klebsiella pneumoniae liver abscess (KPLA) being the most prevalent in Asia. This study aims to develop an effective and comprehensive nomogram combining clinical and radiomics features for early prediction of KPLA. METHODS: 255 patients with PLA from 2013 to 2023 were enrolled and randomly divided into the training and validation cohorts at a 7:3 ratio. The differences between the two cohorts of patients were assessed via univariate analysis. The radiomics features were extracted from imaging data from enhanced CT of liver abscesses. The optimal radiomics features were filtered using the independent sample t-test and least absolute shrinkage and selection operator, and a radiomics score (Rad-score) was calculated by weighting their respective coefficients. Clinically independent predictors were identified from the clinical data and combined with the Rad-score to develop a nomogram by multivariate logistic regression. The predictive performance was evaluated using the area under the receiver operating characteristic curve (AUC), calibration curve, and clinical decision curve. RESULTS: The nomogram incorporated four clinical features of diabetes mellitus, cryptogenic liver abscess, C-reactive protein level, and splenomegaly, and the Rad-score that was constructed based on seven optimal radiomics features. It had an AUC of 0.929 (95% CI, 0.894-0.964) and 0.923 (95% CI, 0.864-0.981) in the training and validation cohorts, respectively. The calibration and decision curves showed that the nomogram had good agreement and clinical applicability. CONCLUSIONS: The clinical-radiomics nomogram performed well in predicting KPLA, hopefully serving as a reference for early diagnosis of KPLA.

Clinical and radiological features of invasive Klebsiella pneumoniae liver abscess syndrome.

BACKGROUND: Recently, a striking new clinical manifestation of Klebsiella pneumoniae (KP) infection referred to as invasive KP liver abscess syndrome (IKPLAS), defined by liver abscess with contemporaneous metastatic KP infections at other body sites has been documented. Until now, however, there have been relatively few reports regarding its radiologic features. PURPOSE: To describe the clinical and radiological features of IKPLAS patients, and to compare them with those with KP liver abscess without metastatic infections to ascertain possible predictors of IKPLAS. MATERIAL AND METHODS: From January 2008 to May 2010, 35 patients (26 men and 9 women; mean age, 59.4 years) with both liver abscess and metastatic KP infections were diagnosed with IKPLAS. Their clinical and radiological features were retrospectively evaluated and compared with those of 25 contemporaneous non-metastatic patients to investigate predictive factors for metastatic infections. RESULTS: The rate of intensive care unit admissions and overall mortality was 34.3% and 17.1% in IKPLAS patients, and was significantly higher than those of the non-metastatic group (8% and 0%, respectively). As for metastatic infections, the lung was the most common site and multiple nodules or masses (n = 9) were the most common manifestations. Univariate analysis revealed that liver abscess ≤5.8 cm, bilobar involvement of abscess and altered mentality were significantly related with IKPLAS. At multivariate analysis, liver abscess ≤5.8 cm was proven to be a significant independent predictor of IKPLAS (OR, 3.6; P = 0.038). In addition, altered mentality was present solely in IKPLAS (25.7% vs. 0%) although its P value (P = 0.052) did not reach a statistical significance at multivariate analysis. CONCLUSION: IKPLAS has significantly worse prognosis than non-metastatic KP abscess patients. In patients with KP liver abscess, liver abscess ≤5.8 cm can be used as an independent predictor of IKPLAS and altered mentality as a very specific feature in diagnosing IKPLAS.