T2Candida Assay in the Diagnosis of Intraabdominal Candidiasis: A Prospective Multicenter Study

Management of intra-abdominal infections: recommendations by the Italian council for the optimization of antimicrobial use

Intra-abdominal infections (IAIs) are common surgical emergencies and are an important cause of morbidity and mortality in hospital settings, particularly if poorly managed. The cornerstones of effective IAIs management include early diagnosis, adequate source control, appropriate antimicrobial therapy, and early physiologic stabilization using intravenous fluids and vasopressor agents in critically ill patients. Adequate empiric antimicrobial therapy in patients with IAIs is of paramount importance because inappropriate antimicrobial therapy is associated with poor outcomes. Optimizing antimicrobial prescriptions improves treatment effectiveness, increases patients' safety, and minimizes the risk of opportunistic infections (such as Clostridioides difficile) and antimicrobial resistance selection. The growing emergence of multi-drug resistant organisms has caused an impending crisis with alarming implications, especially regarding Gram-negative bacteria. The Multidisciplinary and Intersociety Italian Council for the Optimization of Antimicrobial Use promoted a consensus conference on the antimicrobial management of IAIs, including emergency medicine specialists, radiologists, surgeons, intensivists, infectious disease specialists, clinical pharmacologists, hospital pharmacists, microbiologists and public health specialists. Relevant clinical questions were constructed by the Organizational Committee in order to investigate the topic. The expert panel produced recommendation statements based on the best scientific evidence from PubMed and EMBASE Library and experts' opinions. The statements were planned and graded according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) hierarchy of evidence. On November 10, 2023, the experts met in Mestre (Italy) to debate the statements. After the approval of the statements, the expert panel met via email and virtual meetings to prepare and revise the definitive document. This document represents the executive summary of the consensus conference and comprises three sections. The first section focuses on the general principles of diagnosis and treatment of IAIs. The second section provides twenty-three evidence-based recommendations for the antimicrobial therapy of IAIs. The third section presents eight clinical diagnostic-therapeutic pathways for the most common IAIs. The document has been endorsed by the Italian Society of Surgery.

Invasive Fungal Infections after Liver Transplantation

Invasive fungal infections represent a major challenge in patients who underwent organ transplantation. Overall, the most common fungal infections in these patients are candidiasis, followed by aspergillosis and cryptococcosis, except in lung transplant recipients, where aspergillosis is most common. Several risk factors have been identified, which increase the likelihood of an invasive fungal infection developing after transplantation. Liver transplant recipients constitute a high-risk category for invasive candidiasis and aspergillosis, and therefore targeted prophylaxis is favored in this patient population. Furthermore, a timely implemented therapy is crucial for achieving optimal outcomes in transplanted patients. In this article, we describe the epidemiology, risk factors, prophylaxis, and treatment strategies of the most common fungal infections in organ transplantation, with a focus on liver transplantation.

Comparison of Three β-Glucan Tests for the Diagnosis of Invasive Candidiasis in Intensive Care Units

The (1→3)-β-d-glucan (BDG) is a marker of invasive fungal infection that can be detected in serum by different commercial kits. In this study, we compared the performance of the Fungitell assay (FA), the Fungitell STAT assay (STAT), and the Wako β-glucan test (WA) for the diagnosis of invasive candidiasis (IC) in the intensive care unit (ICU). Patients for whom at least one BDG testing was required for a clinical suspicion of IC were retrospectively enrolled. A total of 85 serum samples from 56 patients were tested by the three BDG tests. The rate of IC was 23% (13/56) with a predominance of noncandidemic (intra-abdominal) IC. STAT and WA results exhibited overall good correlation with those obtained by FA (Spearman's coefficient R = 0.90 and R = 0.89, respectively). For the recommended cutoffs of positivity, sensitivity and specificity for IC diagnosis were 77%/51% (FA, 80 pg/mL), 69%/53% (STAT, ratio 1.2), and 54%/65% (WA, 7 pg/mL), respectively. Optimal performance was obtained at 50 pg/mL (FA), ratio 1.3 (STAT), and 3.3 pg/mL (WA) with sensitivity/specificity of 85%/51%, 69%/57%, and 77%/58%, respectively. Overall, the three BDG tests showed comparable but limited performance in this setting with positive and negative predictive values for an estimated IC prevalence of 20% that were in the range of 30 to 35% and 85 to 95%, respectively.

Combining T2Bacteria and T2Candida Panels for Diagnosing Intra-Abdominal Infections: A Prospective Multicenter Study

The T2Bacteria panel is a direct-from-blood assay that delivers rapid results, targeting E. coli, S. aureus, K. pneumoniae, A. baumanii, P. aeruginosa, and E. faecium (ESKAPE pathogens). In this study, T2Bacteria and T2Candida (targeting C. albicans/C. tropicalis, C. glabrata/C. krusei, and C. parapsilosis) were evaluated in parallel with blood cultures in 101 consecutive surgical patients with suspected intra-abdominal infection admitted to the intensive care unit or high dependency unit. Fifteen patients had bacteremia, with T2Bacteria correctly identifying all on-panel (n = 8) pathogens. T2Bacteria was positive in 19 additional patients, 11 of whom had supportive cultures from other normally sterile sites (newly inserted drains, perioperative cultures or blood cultures) within seven days. Six of these eleven patients (55%) received broad-spectrum antibiotics at the sampling time. T2Candida identified the two cases of blood-culture-positive candidemia and was positive in seven additional patients, three of whom were confirmed to have intra-abdominal candidiasis. Of four patients with concurrent T2Bacteria and T2Candida positivity, only one patient had positive blood cultures (candidemia), while three out of four patients had supporting microbiological evidence of a mixed infection. T2Bacteria and T2Candida were fast and accurate in diagnosing on-panel bloodstream infections, and T2Bacteria was able to detect culture-negative intra-abdominal infections.

Diagnosis and Treatment of Invasive Candidiasis

Candida species, belonging to commensal microbial communities in humans, cause opportunistic infections in individuals with impaired immunity. Pathogens encountered in more than 90% cases of invasive candidiasis include C. albicans, C. glabrata, C. krusei, C. tropicalis, and C. parapsilosis. The most frequently diagnosed invasive infection is candidemia. About 50% of candidemia cases result in deep-seated infection due to hematogenous spread. The sensitivity of blood cultures in autopsy-proven invasive candidiasis ranges from 21% to 71%. Non-cultural methods (beta-D-glucan, T2Candida assays), especially beta-D-glucan in combination with procalcitonin, appear promising in the exclusion of invasive candidiasis with high sensitivity (98%) and negative predictive value (95%). There is currently a clear deficiency in approved sensitive and precise diagnostic techniques. Omics technologies seem promising, though require further development and study. Therapeutic options for invasive candidiasis are generally limited to four classes of systemic antifungals (polyenes, antimetabolite 5-fluorocytosine, azoles, echinocandins) with the two latter being highly effective and well-tolerated and hence the most widely used. Principles and methods of treatment are discussed in this review. The emergence of pan-drug-resistant C. auris strains indicates an insufficient choice of available medications. Further surveillance, alongside the development of diagnostic and therapeutic methods, is essential.