Analysis of virulence profiles in clinical isolates of Klebsiella pneumoniae from renal abscesses: clinical significance of hypervirulent isolates.

Introduction: Klebsiella pneumoniae can cause a wide range of infections. Hypervirulent K. pneumoniae (hvKp), particularly associated with the K1 and K2 capsular types, is an increasingly significant microorganism with the potential to cause invasive infections, including renal abscesses. Despite the rising prevalence of hvKp infections, information on renal abscesses caused by K. pneumoniae is limited, and the clinical significance of hvKp associated with specific virulence genes remains elusive. Methods: This study performed at a 1200-bed tertiary hospital sought to identify the clinical and microbiological characteristics of renal abscesses caused by K. pneumoniae, focusing on various virulence genes, including capsular serotypes and multilocus sequence typing (MLST). Results: Over an 8-year period, 64 patients with suspected renal abscesses were reviewed. Ten patients diagnosed with K. pneumoniae-related renal abscesses were ultimately enrolled in the study. Among the isolates from the 10 patients, capsular serotype K2 was predominant (40.0%), followed by K1 (30.0%). The most common sequence type by MLST was 23 (40.0%). In particular, six patients (60.0%) harbored specific genes indicative of hvKp: iucA, peg-344, rmpA, and rmpA2. Conclusions: Our findings highlight the importance of hvKp as a pathogen in renal abscesses. Although the nature of hvKp is relatively unknown, it is widely recognized as a highly virulent pathogen that can infect relatively healthy individuals of various ages and simultaneously cause infections at multiple anatomical sites. Therefore, when treating patients with K. pneumoniae-related renal abscesses, caution is necessary when considering the characteristics of hvKp, such as potential bacteremia, multi-organ abscess formation, and metastatic spread.

A case of renal abscess mimicking metastatic lesion in a patient with lung carcinosarcoma.

Renal abscesses require prompt diagnosis and appropriate intervention, as they can be life-threatening. However, diagnosis based solely on clinical findings is often challenging. We present the case of a 69-year-old woman with left renal masses on follow-up computed tomography (CT) after surgery for pT2aN0M0 lung carcinosarcoma. The masses were localized only in the left kidney without suspected metastatic lesions at other sites. The patient was referred to our department for further evaluation and treatment under a diagnosis of suspected metastatic lung carcinosarcoma of the left kidney. On enhanced CT, the left renal masses, the largest of which had a diameter of 40×36 mm had thick irregular walls gradually enhanced by the contrast media and an internal low-attenuation area. The masses showed heterogeneous signal intensity with a pseudocapsule on T2-weighted magnetic resonance imaging. Clinical symptoms such as fever or costovertebral angle tenderness were absent, and blood and urine tests were not sufficiently inflammatory to suggest a renal abscess. Histopathological findings on CT-guided renal biopsy revealed only inflammatory tissue and no tumor cells. However, because lung carcinosarcoma metastatic nodules could not be ruled out, laparoscopic left nephrectomy was performed for a definitive diagnosis and curative intent. The pathological diagnosis was renal abscess without malignant lesions. Here, we present a case of renal abscess mimicking metastatic lesions in a patient with lung carcinosarcoma. Accurately differentiating renal abscesses from metastatic renal tumors before treatment is often difficult. Renal abscess diagnosis should be considered through a comprehensive evaluation of the clinical findings of individual cases.

A Case Report on Renal Abscess: Rare Diagnosis in a Healthy Young Female With No Risk Factors.

Renal abscess is a rare complication of pyelonephritis known to be linked to recurrent urinary tract infections, anatomical abnormalities, obstruction, and the immunocompromised. Symptoms can be very nonspecific such as fever, chills, and abdominal or flank pain, which makes it more challenging to diagnose; however, this has been made easier with the help of medical imaging. Persistently spiking fevers despite antibiotics should prompt a review for possible abscess formation. We describe a case of renal abscess in a previously healthy young female with no risk factors who was successfully treated with antibiotics and radiologically guided percutaneous drainage.

A Rare Case of Bilateral Renal Abscess from Staphylococcal Infection in a Young Healthy Patient.

Bilateral renal abscess is a rare infectious disease. Most patients have some risk factors for comorbidities, such as diabetes or an abnormal urinary tract, causing abscess formation. The incidence of the disease is infrequent in young healthy adults. Here, we report a case of a previously healthy non-diabetic young man who presented with abdominal pain with a high-grade fever. With clinically persistent abdominal pain, computerized tomography of the whole abdomen was done. The result showed bilateral renal abscess. The culture from the abscess reported Staphylococcus aureus. The patient's clinical abdominal pain and fever resolved after receiving antibiotics for 4 weeks.

Renal artery pseudoaneurysm formation and rupture induced by renal abscess: A case report.

Severe consequences can ensue from the rupture and hemorrhage of a renal artery pseudoaneurysm, necessitating immediate intervention upon detection. To date, no reports exist on the development of renal artery pseudoaneurysms as a result of renal abscesses. This document introduces the first reported case of this occurrence.

Abscesos renales: experiencia en un hospital pediátrico de referencia

Introducción: El absceso renal es infrecuente en pediatría, con clínica y laboratorio inespecíficos. Ante su sospecha, es necesario realizar imágenes para establecer diagnóstico. Objetivo: Describir las características clínico-epidemiológicas, microbiológicas, diagnósticas y terapéuticas de abscesos renales en pediatría. Pacientes y Métodos: Estudio retrospectivo, descriptivo, de pacientes internados con absceso renal, en seguimiento por Infectología del Hospital de Niños Ricardo Gutiérrez, durante 9 años. Resultados: 15 pacientes (67% varones), mediana de edad 9 años (rango [r] 0,7-17). Cuatro pacientes con comorbilidades. El síntoma más frecuente fue fiebre seguido por dolor lumbar. El recuento medio de leucocitos en sangre fue de 15.700/mm3 (r: 7.100-45.000) y la PCR de 193 mg/L (r: 1-362). Cuatro pacientes presentaron urocultivo positivo: dos Escherichia coli, uno Klebsiella pneumoniae y E. coli y otro Candida albicans y K. pneumoniae. Ningún paciente presentó bacteriemia. El diagnóstico se confirmó por ecografía. Se realizó drenaje en siete pacientes, con aislamiento de Staphylococcus aureus en dos y Pseudomonas aeruginosa en uno. El tratamiento incluyó terapia combinada en 67%. Mediana de antibioterapia intravenosa fue 16 días (r: 7-49), total de 28 (r: 14-91). Un paciente requirió terapia intensiva y dos, nefrectomía. Conclusión: Los abscesos renales son infrecuentes, con gran morbimortalidad. Sospechar en paciente con infección del tracto urinario (ITU) de evolución tórpida que persiste febril. En nuestro estudio, la alta sensibilidad de la ecografía renal permitió su diagnóstico precoz.

Background: Renal abscesses are infrequent in pediatrics, with nonspecific clinical and laboratory findings. When suspected, imaging is essential to establish the diagnosis. Aim: To describe the clinical-epidemiological, microbiological, diagnostic and therapeutic characteristics of renal abscesses in pediatrics. Methods: Retrospective and descriptive study of hospitalized patients with renal abscess, followed by Infectious Diseases Department of Ricardo Gutiérrez Children's Hospital during 9 years. Statistical analysis: Epi Info 7.2.2.6. Results: 15 patients (67% male), median age 9 years (range [r] 0.7-17) were included. Four patients had underlying disease. The most frequent symptom was fever, with a median duration of 10 days (r:1-36), followed by lumbar pain. The median white blood cell count was 15,700/mm3 (r: 7,100-45,000) and CRP 193mg/L (r: 1-362). Four patients presented positive urine culture: 2 Escherichia coli, 1 Klebsiella pneumoniae and E. coli and 1 Candida albicans and K. pneumoniae. No patient had bacteremia. The diagnosis of abscess was confirmed by ultrasound. Surgical drainage was performed in 7 patients, with isolation of Staphylococcus aureus in 2 and Pseudomonas aeruginosa in 1. Empirical treatment included 3rd generation cephalosporin, combined in 67% of cases. The median of intravenous antibiotic therapy was 16 days (r: 7-49) with a total of 28 days (r:14-91). One patient required transfer to intensive care unit and 2 nephrectomy. Conclusion: Renal abscesses are infrecuent in pediatrics, but they present significant morbidity and mortality. It should be suspected in patients with urinary tract infection (UTI)with torpid evolution that persists with fever without antibiotic response. In our study, the high sensitivity of renal ultrasound allowed early diagnosis.

Mycotic Aneurysm of the Thoracoabdominal Aorta: A Diagnostic Challenge.

Mycotic aortic aneurysms (MAAs) are a rare form of aortic aneurysms that are associated with catastrophic outcomes if not diagnosed and treated on time. However, MAAs are a diagnostic challenge owing to their often nonspecific presentation. In this study, we present a case of a 42-year-old female with a pertinent history of intravenous drug use who presented with generalized body pain for two weeks and was found to have a mycotic thoracoabdominal aortic aneurysm (TAAA) extensively involving adjacent structures, including lungs with pleural cavity and upper renal pole. Not only does this case highlight the difficulty in early diagnosis and complex pathology of a mycotic TAAA, but it also illustrates the multidisciplinary approach required to effectively treat them.

Association between the imaging characteristics of renal abscess and vesicoureteral reflux.

INTRODUCTION: Renal abscesses are rare in pediatric populations. We aimed to highlight the differences in the computed tomography (CT) imaging characteristics of renal abscesses in patients with and without vesicoureteral reflux (VUR). MATERIALS AND METHODS: Thirteen children with renal abscesses were included and categorized into those with and without VUR. Blood and urine culture results were recorded as positive or negative. Imaging characteristics were recorded: with/without subcapsular fluid collection, with/without upper/lower pole involvement, and with single/multiple lesions in kidneys. Fisher's exact test was used for intergroup comparisons of the rate of positive pathogens and imaging characteristics. RESULTS: Nine patients had VUR (45.9%). Blood and urine culture were positive in two (15.4%) and seven cases (53.8%), respectively. There was no significant difference in the rate of pathogen-positive blood and urine cultures (blood culture positive/negative status with VUR vs. that without VUR = 2/7 vs. 0/4, p > 0.999, urine culture positive/negative status with VUR vs. that without VUR = 4/5 vs. 3/1, p = 0.559). The two groups differed significantly regarding subcapsular fluid collection presence (with/without subcapsular fluid collection with VUR vs. that without VUR = 9/0 vs 1/3, p = 0.014). There was no significant difference in upper/lower pole involvement (with/without involving upper/lower pole with VUR vs. that without VUR = 8/1 vs 2/2, p = 0.203). Patients with VUR were non-significantly more likely to have multiple lesions compared to those without VUR. CONCLUSIONS: VUR was associated with subcapsular fluid collection and possibly with multiple lesions, indicating the need for prompt detection of and specific treatment for VUR in cases with these findings.

Segmental renal vein thrombosis: An unusual complication of acute pyelonephritis.

Renal vein thrombosis is not a common manifestation in the context of acute pyelonephritis. We report the case of a 29-year-old female diabetic patient that was admitted to our department for an episode of complicated acute pyelonephritis. Initial imaging showed a left lower polar abscess of 27 mm and urine cultures grew community acquired K. Pneumoniae. Two days after the patient was discharged, she was readmitted with worsening symptoms. Repeat imaging showed stability in the size of the abscess and revealed a left lower segmental vein thrombosis. The patient responded favorably to antibiotics and heparin-warfarin therapy.

Large Renal Abscess in Pregnancy: Case Report of a Rare Finding.

The incidence of renal abscesses during pregnancy has not been well-established. A renal abscess is usually secondary to the complications of acute pyelonephritis and can lead to severe consequences, including fetal and/or maternal death. Little is known about the incidence of renal abscesses in pregnant women; however, the literature consistently refers to it as an extremely rare occurrence. We report a case of a large renal abscess discovered in the early postpartum period following a recurrent urinary tract infection and flank pain during pregnancy. The patient was successfully managed with abscess drainage and prolonged antibiotics.

Role of MRI in the evaluation of acute pyelonephritis in a high-risk population with renal dysfunction: a prospective study.

AIMS: This study aims to evaluate the (a) accuracy of conventional and diffusion-weighted-imaging (DWI) sequences in the diagnosis of acute pyelonephritis and (b) minimum apparent diffusion coefficient (ADC) values for the diagnosis of acute pyelonephritis and the differentiation of renal abscesses from acute pyelonephritis. MATERIALS AND METHODS: Ultrasound, conventional MRI sequences, and DWI were used to evaluate the kidneys in 68 patients suspected to have acute pyelonephritis. Multiple similar regions of interest (ROIs) were placed over the renal parenchyma with visually identifiable diffusion restriction, over the non-diffusion-restricted renal parenchyma of affected kidneys and over the normal kidneys. Corresponding minimum ADCs were noted for analysis. Pyelonephritis was confirmed based on clinical criteria, laboratory findings, and by resolution/development of known complications of pyelonephritis. RESULT: DWI showed the highest sensitivity(100%), while DWI read with T2-weighted imaging (both being positive) showed the highest specificity(100%) for the diagnosis of acute pyelonephritis in our population with a high baseline creatinine. The minimum-ADC of the nephritic diffusion-restricted area in patients with confirmed pyelonephritis was significantly lower than the minimum-ADC in patients without pyelonephritis [(0.934 ± 0.220, mean ± SD) vs (1.804 ± 0.404) × 10-3 s/mm2] (p < 0.001). ROC cut-off of minimum-ADC for the diagnosis of acute pyelonephritis was 1.202 × 10-3 s/mm2 (area under curve 0.978). The minimum-ADC of the abscesses were significantly lower when compared to the minimum-ADC of the nephritic diffusion-restricted portion of the same kidney [(0.633 ± 0.248) vs (0.850 ± 0.191) × 10-3 s/mm2] (p < 0.001). CONCLUSION: DWI is an excellent stand-alone imaging tool that can be combined with conventional sequences for the diagnosis of APN even in patients with high serum-creatinine or other contraindications to intravenous contrast. Further, ADC values can be used to differentiate between renal abscesses and uncomplicated pyelonephritis.

Acute Acalculous Cholecystitis Associated with Abscesses-An Unknown Dual Pathology.

(1) Introduction and Aims: Little is known about the relationship between renal pathology and gallbladder pathology, although the two organs (the gallbladder and the right kidney) are in close proximity to one another. If a renal abscess disseminates, the gallbladder would be one of the secondary organs involved. As the bile provides a favorable environment for the development of pathogenic germs, it allows for the development of acute cholecystitis, even if calculi are absent, thus resulting in the development of acute acalculous cholecystitis. The aim of our study was to analyze the association between acute acalculous cholecystitis (AAC) and renal abscesses. (2) Methods: A department-wide retrospective cohort observational study including 67 patients with renal abscesses, with a mean age of 34.5+/-16.21 years and with five males and 62 females, was conducted. All of the patients were examined by an abdominal ultrasound. The lab tests included CBC with differential liver enzymes and serum bilirubin (in order to assess alterations in the liver function which can be associated with AAC) and serum creatinine (in order to assess the renal function). Blood culture and urine culture tests were also performed. (3) Results: Of the 67 patients with renal abscesses, eight (11.94%) were associated with acute cholecystitis: four cases (5.97%) of acalculous cholecystitis and four cases (5.97%) of calculous cholecystitis, two of which presented biliary sludge (acute micro-calculous cholecystitis). All four cases of acute acalculous cholecystitis presented with sepsis, and there was one case of septic shock at onset. We did not observe an impairment in renal function in the patients presenting with acute acalculous cholecystitis, and hepatic impairment was inconstant and moderate. All of the cases had a favorable outcome after a prompt initiation of intensive antibiotic therapy; both the renal abscess and the acute acalculous cholecystitis receded without further complications. (4) Conclusions: The association of acute acalculous cholecystitis with renal abscesses could be related to the possibility of germ dissemination from the infectious focus. In the case of a renal abscess, careful clinical, lab, and imaging exams of the gallbladder are recommended in order to ensure early therapeutic intervention in the event of an association with acute acalculous cholecystitis.

Case report: Sarcomatoid urothelial carcinoma of the renal pelvis masquerading as a renal abscess.

Sarcomatoid urothelial carcinoma (SUC), a rare tumor of the urinary tract epithelium, exhibits a high degree of malignancy and therefore a poor prognosis. Due to the absence of specific clinical presentations and imaging findings, SUC of the renal pelvis masquerades as a renal abscess is frequently under-recognized or misdiagnosed as benign inflammatory disease, resulting in delayed or erroneous treatment. Here, we report a patient with SUC of the renal pelvis who presented with a renal abscess. Repeated anti-inflammatory treatment was ineffective. Unexpectedly, cancerous cells were detected in subsequent exfoliative cytology of nephrostomy drainage fluid. In accordance with this, radical surgery and postoperative chemotherapy were conducted. Fortunately, neither recurrence nor metastasis occurred during a one-year follow-up.

Clinical features, outcomes and predictors of drug resistance and complications in patients admitted with pyelonephritis.

Drug resistance and the presence of structural complications have significant implications for the treatment of acute pyelonephritis. We aimed to examine the predictors of drug resistance and complications in a retrospective cohort of patients admitted with pyelonephritis. 188 patients were included in this study. Patients who had had a urinary catheterization in the previous month and who lived outside the district in which the hospital was located were more likely to have ESBL infections. Carbapenem resistance was associated with recent urinary catheterization, a positive urine nitrate test, hypotension requiring vasopressors and the need for intensive care. A history of flank pain, urea level >13.3 mmol/L, a differential neutrophil count >75% and a urinalysis with >1000 leucocytes per high power field was associated with an increased risk of complications. A score derived from these variables to predict structural complications of infection had a sensitivity of 77.8% and a specificity of 67.1.

Incidence of renal scarring on technetium-99 m dimercaptosuccinic acid renal scintigraphy after acute pyelonephritis, acute focal bacterial nephritis, and renal abscess.

OBJECTIVE: To evaluate the association between the incidence of renal scarring on technetium-99 m dimercaptosuccinic acid (DMSA) renal scintigraphy and the severity of renal parenchymal infections, such as acute pyelonephritis (APN), acute focal bacterial nephritis (AFBN), and renal abscess, based on computed tomography (CT) diagnosis. METHODS: Sixty-one children with renal parenchymal infections were included and classified into two groups: those with (renal scarring group) and without renal scarring (non-renal scarring group) on chronic-phase DMSA renal scintigraphy. The severity of renal parenchymal infection was classified into three grades using CT: APN, AFBN, and renal abscess as grades 1, 2, and 3, respectively. The severity of renal parenchymal infection, vesicoureteral reflux (VUR) grade, and intrarenal reflux occurrence during voiding cystourethrography (VCUG) were evaluated between the renal and non-renal scarring groups. Fisher's exact test and Mann-Whitney U test were used for statistical analysis. RESULTS: Renal scars were detected in 28 (45.9%) of the 61 patients. We found that 2/9 (22.2%), 18/41 (43.9%), and 8/11 (72.7%) patients with APN (grade 1), AFBN (grade 2), and renal abscess (grade 3) had renal scarring, respectively. There was a significant difference in the grade of severity of renal parenchymal infection between the renal (median = 2 [interquartile range, 2-3]) and non-renal (median = 2 [interquartile range, 2-2]) scarring groups (p = 0.023). There was a significant difference in the grade of VUR between the renal (median = 3 [interquartile range, 0-4]) and non-renal (median = 0 [interquartile range, 0-2]) scarring groups (p = 0.004). No significant difference in intrarenal reflux occurrence was observed between the renal (present/absent: 3/25) and non-renal (present/absent: 0/29) scarring groups (p = 0.112). CONCLUSION: Our results showed that pediatric patients with renal scarring on chronic-phase DMSA renal scintigraphy tended to have a more severe renal infection.

An update on pyelonephritis: role of contrast enhancement ultrasound (CEUS).

Acute pyelonephritis (APN) is a bacterial infection causing inflammation of the kidneys. Diagnosis is usually based on clinical and laboratory findings. Imaging is required if a complication is suspected in acute pyelonephritis to assess the nature and extent of the lesions and to detect underlying causes. CT represents the current imaging modality of choice in clinical practice. CEUS is an alternative that has been proven to be equally accurate in the detection of acute pyelonephritis renal lesions. CEUS allows us to distinguish small simple nephritic involvement from abscess complications and to follow their evolution over time during antibiotic therapy. The absence of ionizing radiation and the lack of nephrotoxicity make CEUS an ideal tool in the study of pyelonephritis.

Renal Abscess Drainage Using a Novel Transgastric Endoscopic Approach: A Case Report.

Renal and perinephric abscesses are rare purulent infections within or around renal parenchyma, typically treated with antibiotics or various procedural approaches depending on abscess size. In this case report, we describe the novel use of a transgastric endoscopic ultrasound (EUS)-guided technique with placement of a stent for drainage between a renal abscess and the stomach in a patient who had failed attempted percutaneous drainage twice and where an open surgical approach was deemed inappropriate. The patient presented with a chief complaint of left flank pain, with CT revealing a ~4 x 4 cm renal abscess in the upper pole of the left kidney. Urology, Infectious Disease, and Interventional Radiology were consulted. Following two failed attempts at percutaneous drain placement, the patient elected for EUS-guided transgastric stent placement for drainage. The stent was removed by postoperative day two after significant decompression of the abscess. He was advised to follow up outpatient with Urology to confirm full renal abscess resolution.

A case of Citrobacter koseri renal abscess and review of the literature.

Citrobacter species are anaerobic gram-negative bacteria that are known to cause infections in immunocompromised hosts, particularly in hospital settings. Their opportunistic nature and tendency to develop antibiotic resistance make Citrobacter species challenging to treat. Renal or perinephric abscess formation as a result of Citrobacter infection is uncommon, having only previously been reported in four cases. We present a case of a 70-year-old man with diabetes and prostate cancer who was diagnosed with an 18 cm perinephric and a 10 cm perihepatic abscess caused by Citrobacter koseri. The patient required drains and re-positioning of the drains multiple times in addition to a prolonged course of antibiotics to achieve complete radiographic resolution. This case highlights the challenges in treating renal and perinephric abscess, as it required drain re-placements two additional times after the initial placement and an additional 4 weeks of antibiotics. Successful treatment for larger abscesses usually requires a two-arm approach, with antibiotics in combination with either percutaneous or surgical abscess drainage.

Case Report: Robot-assisted laparoscopic nephron-sparing surgery for a renal abscess mimicking a tumor.

The differential diagnosis of renal tumors and abscesses is crucial owing to their different treatments. Although antibacterial administration and radiological examination are excellent means for distinction, misdiagnosis is common and may lead to severe consequences, such as the need for nephrectomy. Here, we report a case involving a 52-year-old Asian woman with a renal mass for which a differential diagnosis was challenging. The mass persisted after administration of intravenous antibiotic therapy for 1 month. A computed tomography scan indicated an inflammatory lesion, whereas magnetic resonance imaging suggested a diagnosis of a tumor. Despite these indications, a right renal abscess was suspected during robot-assisted laparoscopic surgery, and nephron-sparing surgery was performed, which allowed confirmation of the final pathological result by biopsy specimen. Postoperatively, the mass gradually decreased in size after antibiotic therapy for a further month. This case, in which a renal abscess mimicked a tumor and the patient almost underwent a nephrectomy, highlights the need for caution in establishing therapeutic schedules for patients with inaccurate diagnoses. The management strategies for such patients must be reviewed and improved.

[Renal cell carcinoma mimicking a renal abscess]. / Carcinome rénal se présentant sous forme d'un abcès rénal.

With the development of modern imaging, incidental findings of renal neoplasia are increasingly frequent. However, renal cell carcinoma can also rarely present as an atypical form and can be confused with benign pathologies such as renal abscess or pyelonephritis. We present the case of a renal neoplasia largely mimicking a renal abscess.

Avec le développement de l'imagerie moderne, la découverte fortuite des néoplasies rénales est de plus en plus fréquente. Néanmoins, le carcinome rénal peut également rarement se présenter sous une forme atypique et peut alors être confondu avec des pathologies bénignes comme un abcès rénal ou une pyélonéphrite. Nous présentons le cas d'une néoplasie rénale se manifestant trompeusement sous la forme d'un abcès rénal.