We aimed to compare the efficacy of ceftazidime-avibactam (CAZ-AVI) versus the best available therapy (BAT) in solid organ transplant (SOT) recipients with bloodstream infection caused by carbapenemase-producing Klebsiella pneumoniae (CPKP-BSI). A retrospective (2016-2021) observational cohort study was performed in 14 INCREMENT-SOT centers (ClinicalTrials.gov identifier: NCT02852902; Impact of Specific Antimicrobials and MIC Values on the Outcome of Bloodstream Infections Due to ESBL- or Carbapenemase-producing Enterobacterales in Solid Organ Transplantation: an Observational Multinational Study). Outcomes were 14-day and 30-day clinical success (complete resolution of attributable manifestations, adequate source control, and negative follow-up blood cultures) and 30-day all-cause mortality. Multivariable logistic and Cox regression analyses adjusted for the propensity score to receive CAZ-AVI were constructed. Among 210 SOT recipients with CPKP-BSI, 149 received active primary therapy with CAZ-AVI (66/149) or BAT (83/149). Patients treated with CAZ-AVI had higher 14-day (80.7% vs 60.6%, P = .011) and 30-day (83.1% vs 60.6%, P = .004) clinical success and lower 30-day mortality (13.25% vs 27.3%, P = .053) than those receiving BAT. In the adjusted analysis, CAZ-AVI increased the probability of 14-day (adjusted odds ratio [aOR], 2.65; 95% confidence interval [CI], 1.03-6.84; P = .044) and 30-day clinical success (aOR, 3.14; 95% CI, 1.17-8.40; P = .023). In contrast, CAZ-AVI therapy was not independently associated with 30-day mortality. In the CAZ-AVI group, combination therapy was not associated with better outcomes. In conclusion, CAZ-AVI may be considered a first-line treatment in SOT recipients with CPKP-BSI.

That the rate of oral absorption varied from dose to dose. Typical linezolid peak concentrations are 12-26 mg/L 2 h after oral doses and trough concentrations are typically 3-9 mg/L. 1-3 In this infant, despite q8h dosing, peak and trough concentrations were lower than typically seen. The volume of distribution divided by bioavailability (Vz/F), clearance divided by bioavailability (CL/F), elimination rate constant (k el , estimated with three concentrations), half-life (t 1/2) and AUC 0-8 were estimated at 3.48 L, 1.75 L/h, 0.50 h 21 , 1.38 h and 16.56 mg. h/L, respectively. The pharmacokinetic profile of oral linezolid in our infant differed from what has been published in the literature for full-term infants. Full-term infants who received single doses of iv linezolid had much higher peak plasma concentrations, a larger AUC and a slower clearance. 8 Our infant was born .3 months premature and was treated at a post-gestational age of 1 month (not equivalent to a full-term infant of the same age); therefore, direct correlation is challenging due to the differences in characteristics of the infants in the published studies. 5,6,8,9 The C max and AUC were lower in our infant and apparent elimination t 1/2 faster than what has been reported in full-term infants. Reasons for this may include incomplete absorption (F, 1), faster clearance or a smaller actual volume of distribution. We were only able to estimate Vz/F, leaving our assessment of this parameter less than optimal. Pharmacokinetic data reported in studies in infants and neonates have utilized the iv formulation of linezolid and studied the disposition of the drug after a single dose, whereas our infant received oral linezolid suspension and pharmacokinetic analysis was done at steady-state. This also may explain some of the differences in pharmacokinetic parameters. Kosaka et al. 10 reported plasma levels in four children (aged ,30 months) receiving linezolid for MRSA mediastinitis. A serum concentration of ,2 mg/L linezolid was needed to inhibit growth for 90% of organisms (MIC 90). Two patients were treated iv with a 90 min infusion at 10 mg/kg q8h initially and were switched to an oral regimen at the same dose. Two other patients were given linezolid orally at a dose of 10 or 15 mg/kg q8h. The linezolid trough concentrations were ≥3.5 mg/L in patients treated with iv linezolid. Lower trough concentrations were seen with oral administration of linezolid. In one 3-month-old child, who was the youngest, undetectable serum trough concentration (,0.1 mg/L) was documented when iv linezolid was changed to oral therapy at a dose of 10 mg/kg q8h; hence, the dose of linezolid was increased from 10 to 15 mg/kg. Preterm infants are at increased risk of nosocomial bacterial infection with multiresistant Gram-positive pathogens. Linezolid seems to be a safe and potent alternative treatment for these infants. The benefits of linezolid compared with vancomycin include its availability as an oral formulation. Owing to the variability of linezolid kinetics in infants, especially in premature infants as in our case, we would recommend therapeutic serum concentrations be monitored at steady-state and dosing adjusted accordingly. Additional studies are needed to evaluate the steady-state pharmacokinetic disposition of oral linezolid in children.

Background: Whipple’s disease (WD) is a rare infection caused by Tropheryma whipplei. Diagnosis is challenging and requires a combination of several data sets, such as patient history, clinical and laboratory investigations, and endoscopy with histology analyses. While persistent diarrhea is a common symptom, WD can affect multiple organs. Case description: We present the case of a 66-year-old immunocompetent patient with WD and a history of Helicobacter pylori infection who developed chronic diarrhea. Colonoscopy and histopathological analysis revealed the presence of foamy macrophages with periodic acid-Schiff-positive particles. Subsequently, molecular methods confirmed the clinical WD diagnosis and metagenomic analyses further identified a co-infection with Giardia intestinalis. The patient fully recovered after 14 months of antibiotic therapy. During pharmacological treatment, clinical and laboratory follow-ups were conducted at 6 and 12 months, and microbiome profiles were also analyzed to identify the most abundant species in the samples. Conclusion: The metagenomic analyses showed the eradication of the two pathogens and a progressive restoration to a healthy/balanced status after antibiotic therapy.

In solid organs post-transplant, bacterial infections can complicate the course of recovery with devastating consequences, such as graft loss and death. We provide an expert review on early post-liver transplant bacterial infections, with a focus on infections with multi-drug-resistant organism (MDRO) etiologies. Best practice recommendations are derived from a combination of available evidence and expert consensus. The main challenge in managing antibiotic therapy arises in patients with severe clinical conditions but negative MDRO screening results, as well as in those with positive MDRO screening results but uncomplicated infections. With the aim of shedding light on these “gray areas”, we propose an algorithm where the patient is stratified as being at low risk or high risk of developing an MDRO infection.

Background: Cysticercosis is caused by the larval stages of Taenia and Versteria species. While Taenia solium , associated with a domestic life cycle, is the primary etiological agent of human (neuro)cysticercosis worldwide, sporadic cases involving Taenia species linked to wildlife have also been reported. A 72‑year‑old immunocompetent woman presented in October 2024 to the Emergency Department with paresthesia, gait imbalance, and severe headache. Neuroimaging revealed a <1‑cm edematous lesion in the frontal cortex, suspicious for metastasis. Surgical removal was performed. Histopathological examination showed necrotic tissue with abundant inflammatory infiltrate, ruling out neoplasia and raising suspicion of an infectious etiology. She was discharged in February 2025 with improved symptoms. Ongoing follow-up demonstrated progressive improvement leading to complete remission. Methods: Serological tests, coproparasitological examinations, and panfungal PCR targeting the 18S rRNA gene were performed. Intraoperative material, including formalin-fixed paraffin-embedded (FFPE) tissue samples, was collected and processed for histological, immunohistochemical, and molecular analyses. Histological sections were stained with hematoxylin and eosin (H&E) and Periodic acid–Schiff (PAS). Immunohistochemical analyses were carried out on FFPE sections to investigate infection with Echinococcus spp. For molecular analysis, genomic DNA was extracted from FFPE tissue using a dedicated commercial kit, following the manufacturer’s instructions. Mitochondrial gene targets ( cox1, nad1, and 12S rRNA) were amplified by PCR and subsequently sequenced. Results: Serological tests, coproparasitological examinations, and panfungal PCR targeting the 18S rRNA gene were negative. Histological analysis showed an inflammatory lesion with a necrotic core, while immunohistochemical analyses were negative for Echinococcus spp. Molecular analysis was positive, and sequence and phylogenetic analyses identified the cestode Taenia martis . Conclusions: This finding underscores the need for clinicians to consider less common Taenia species as potential causes of cysticercosis and neurocysticercosis, particularly when serological tests are negative or inconclusive despite a clinically suggestive presentation. Graphical