Background and Objectives: Acute and obstructive pyelonephritis (AOP) management, despite advancements in diagnostic imaging and antimicrobial therapy, is characterized by delayed recognition and increasing antimicrobial resistance. This review aimed to summarize current evidence regarding the clinical characteristics, microbiological spectrum, biomarkers, and imaging findings associated with AOP. Materials and Methods: A systematic review was conducted according to PRISMA guidelines and registered in PROSPERO (CRD420251162736). Literature searches were performed across the PubMed, Scopus, and Web of Science databases for articles published between January 2014 and 31 March 2025 using the term “acute obstructive pyelonephritis”. Inclusion criteria comprised original full-text English-language studies, published in the last 10 years and conducted in adults, reporting clinical, laboratory, microbiological, and imaging characteristics. Exclusion criteria are letters to the editor, expert opinions, case reports, conference or meeting abstracts, reviews, and redundant publications; having unclear or incomplete data; and being performed on cell cultures or on mammals. The quality of included studies was assessed using the Newcastle–Ottawa Scale. Results: Twenty-three studies met the inclusion criteria. AOP predominantly affected elderly patients with comorbidities, especially diabetes mellitus and urinary tract obstruction. Predictors of septic shock included thrombocytopenia, hypoalbuminemia, elevated procalcitonin (>1.12 µg/L), presepsin, and a neutrophil-to-lymphocyte ratio ≥ 8.7. Escherichia coli remained the leading pathogen (60–95%) with extended-spectrum β-lactamase (ESBL) rates between 20 and 70%, followed by Klebsiella pneumoniae. CT demonstrated 71–100% sensitivity for detecting obstructive complications, confirming its superiority over ultrasound, while MRI provided comparable diagnostic accuracy in selected cases. Source control through double-J stenting or percutaneous drainage significantly improved survival. Conclusions: AOP requires prompt recognition and early decompression to prevent sepsis-related mortality. Biomarkers such as procalcitonin, presepsin, and neutrophil to lymphocyte ratio enhance risk stratification, while CT remains the gold-standard imaging modality. The increasing prevalence of ESBL-producing pathogens underscores the need for antimicrobial stewardship and individualized therapeutic strategies guided by local resistance data.

Background: Complicated acute pyelonephritis (AP) is a severe upper urinary tract infection associated with systemic inflammation, organ dysfunction, and the risk of sepsis. The increasing prevalence of antimicrobial-resistant (AMR) organisms can alter clinical management. This study aimed to characterize the biological profile of inpatients with complicated AP and to eventually identify laboratory markers associated with risks of sepsis and AMR infections. Material and Methods: A retrospective observational analysis on 553 adult inpatients diagnosed with complicated AP between 2021 and 2025 was conducted in a tertiary center. Demographic, clinical, and biological parameters were analyzed, including inflammatory markers and renal and hepatic markers. Results: Group characteristics included a mean age of 63.82 ± 15.67 years, and 63% were female. At admission, inflammatory markers were raised, with leukocytosis (15.6 ± 5.8 × 10³/µL), neutrophilia (10.1 ± 4.7 × 10³/µL), and elevated C-reactive protein (CRP) (median 43.2 mg/dL). Coagulation activation was significant with elevated fibrinogen of 747 ± 145 mg/dL and D-dimer with a median level of 1249 ng/mL, of which 58% exceeded 1000 ng/mL. Mild to moderate renal impairment was frequently observed (creatinine 1.69 ± 0.76 mg/dL). In multivariate analysis, no biological parameter proved to be an independent predictor of AMR status among organisms. Discussion and Conclusions: Inpatients with complicated AP showed a pronounced inflammatory and procoagulant biological profile that did not vary between AMR pathogen and non-AMR pathogen infections. This suggests that the clinical value of biomarkers, such as leukocyte and neutrophile, CRP, D-dimer, fibrinogen, procalcitonin, urea, and creatinine, lies primarily in assessing disease severity rather than predicting antimicrobial resistance. The microbiological profile was dominated by Gram-negative pathogens, particularly Escherichia coli, although a heterogeneous spectrum of microorganisms was identified.

Introduction: Leishmaniasis is a globally widespread zoonotic infection, including in the Mediterranean basin. There are four known types of disease: cutaneous, mucocutaneous, visceral and post Kala-Azar dermal leishmaniasis. Visceral Leishmaniasis (VL) is caused by Leishmania (L.) infantum and L. donovani. It manifests through general symptoms, hepatosplenomegaly and pancytopenia in children younger than ten years old and immunocompromised adults. Case presentation: An 18-year-old female patient is admitted for evaluation, in the context of prolonged febrile syndrome, after successive respiratory intercurrents, weight loss, night sweats and arthromyalgias, with the onset 8 months before. When interviewing the patient, one travel to Valencia, in October 2023, was reported. General laboratory analysis and abdominal ultrasound investigations showed no alterations. However, a specific Western blot test for anti-L. infantum IgG antibodies, was positive. Under treatment with amphotericin B, symptoms resolved and the following PCR test was negative. Conclusions: Leishmaniasis was identified in a female patient without specific risk factors. The finding underlines the need for a closer collaboration with infectious disease specialists, depending on the clinical and epidemiological context.

Antimicrobial resistance represents a major global challenge for healthcare systems, particularly in urinary tract infections (UTIs), where empirical antibiotic therapy is frequently required. Acute pyelonephritis (AP) remains a severe condition, requiring prompt diagnosis and treatment. Local epidemiological data are essential for optimizing therapeutic strategies. The aim of this study was to analyze the pathogen distribution and antimicrobial resistance (AMR) patterns in patients with complicated AP. An observational, analytical study on community-acquired and hospital-acquired AP was conducted on patients admitted with complicated AP between January 2021 and December 2025. After applying the inclusions and exclusions criteria, 553 urinary isolates with complicated AP were analyzed to determine pathogen distribution and phenotypic AMR patterns derived from antimicrobial susceptibility testing. A total of 109 (19.7%) AMR isolates presented resistance phenotype. Resistant phenotypes were more frequently observed among male gender; age did not reach statistical significance. This study highlights the continued predominance of Escherichia coli in complicated AP while demonstrating a significant AMR burden among non-Escherichia coli pathogens, particularly Klebsiella and Pseudomonas species. These findings emphasize the importance of local epidemiological surveillance and culture-guided antibiotic therapy in the management of complicated UTIs.