Interleukin-2-mediated CD4 T-cell activation correlates highly with effective serological and T-cell responses to SARS-CoV-2 vaccination in people living with HIV.

People living with HIV (PLWH) despite having an appreciable depletion of CD4+ T-cells show a good severe acute respiratory syndrome coronavirus 2 vaccination response. The underlying mechanism(s) are currently not understood. We studied serological and polyfunctional T-cell responses in PLWH receiving anti-retroviral therapy stratified on CD4+ counts as PLWH-high (CD4 ≥ 500 cells/mm3) and PLWH-low (<500 cells/mm3). Responses were assessed longitudinally before the first vaccination (T0), 1-month after the first dose (T1), 3-months (T2), and 6-months (T3) after the second dose. Expectedly, both PLWH-high and -low groups developed similar serological responses after T2, which were also non-significantly different from age and vaccination-matched HIV-negative controls at T3. The immunoglobulin G titers were also protective showing a good correlation with angiotensin-converting enzyme 2-neutralizations (R = 0.628, p = 0.005). While surface and intracellular activation analysis showed no significant difference at T3 between PLWH and controls in activated CD4+CD154+ and CD4+ memory T-cells, spike-specific CD4+ polyfunctional cytokine expression analysis showed that PLWH preferentially express interleukin (IL)-2 (p < 0.001) and controls, interferon-γ (p = 0.017). CD4+ T-cell counts negatively correlated with IL-2-expressing CD4+ T-cells including CD4+ memory T-cells (Spearman ρ: -0.85 and -0.80, respectively; p < 0.001). Our results suggest that the durable serological and CD4+ T-cell responses developing in vaccinated PLWH are associated with IL-2-mediated CD4+ T-cell activation that likely compensates for CD4+ T-cell depletion in PLWH.

A Digital Approach to Improve Infection Screening Among Solid Organ Transplant Candidates.

BACKGROUND: Pretransplant infection screening (IS) of potential organ recipients is essential to optimal outcome of solid organ transplantation (SOT). METHODS: A pre-post study was performed during 2020-2023 to investigate the impact of the STREAM (Solid organ TRansplant stEwArdship and Multidisciplinary approach) intervention to improve IS in SOT. The intervention, performed in 2022, included the implementation of IS through educational meetings, local guidelines, and the availability of a digital screening tool. The objective of the study was the assessment of IS completion, including a list of 17 laboratory tests and the investigation of vaccination status. The reduction of unnecessary tests was also analyzed. The test of proportions and a multilevel multivariate Poisson regression model were used to compare IS completion before and after STREAM. infectious diseases (ID) consultation and urgent evaluation were investigated as predictors of IS completion. RESULTS: A total of 171 patients were enrolled, including liver (44%), heart (32%), and kidney (24%) transplant candidates. Mean age was 56 ± 11 years, and most patients (77%) were males. Ninety-five (56%) patients were included before the intervention and 76 (44%) after STREAM. IS completion increased after STREAM (IRR 1.41, p < 0.001) with significant improvement recorded for seven (39%) IS items. Unnecessary tests decreased by 43% after the intervention. ID consultation (IRR 1.13, p = 0.02) and urgent evaluation (p = 0.68, p < 0.001) were predictors of IS improvement. CONCLUSIONS: STREAM was successful in improving IS completion. Further research is needed to investigate the impact of this intervention on posttransplant infections.

Carbapenemase-producing Enterobacteriaceae in transplant patients.

Carbapenemase-producing Enterobacteriaceae (CPE) are a serious public health concern and represent a major threat to immunocompromised hosts, including solid organ (SOT) and stem cell transplant (HSCT) recipients. Transplant patients are at particular risk of developing CPE colonization and/or infection due to their frequent exposure to prolonged courses of broad-spectrum antibiotics, altered immunocompetence and exposure to invasive procedures and immunosuppressive drugs. Gut colonization with CPE, in particular carbapenem-resistant Klebsiella pneumoniae, may occur before or after SOT in 2%-27% of patients and among 2%-9% of HSCT and has been associated with increased risk of developing CPE infections. In endemic areas, CPE infections occur in up to 18% of SOT, and HSCT patients can account for 5%-18% of all patients with CPE bacteraemia. Mortality rates up to 70% have been associated with CPE infections in both patient populations. The rapid initiation of an active therapy against CPE is advocated in these infections. Therapeutic options, however, are limited by the paucity of novel compounds that are currently available and by potential antibiotic-associated toxicities. Therefore, a multidisciplinary approach involving infection control and antimicrobial stewardship programmes still represents the mainstay for the management of CPE infections among transplant patients. The evidence for the use of prevention strategies such as CPE-targeted perioperative prophylaxis or gut decolonization is still scarce. Large, multicentre trials are required to better define prevention strategies and to guide the management of CPE infections in the transplant setting.

The role of combination therapy in the treatment of severe infections caused by carbapenem resistant gram-negatives: a systematic review of clinical studies.

BACKGROUND: Effective treatment of sepsis due to carbapenem-resistant Gram-negative bacteria (CR-GNB) remains a challenge for clinicians worldwide. In recent years, the combination of antibiotics has become the preferred treatment strategy for CR-GNB infection. However, robust evidence to support this approach is lacking. This systematic review aimed at critically evaluating all available antibiotic options for CR-GNB sepsis with particular focus on combination. METHODS: We systematically searched published literature from January 1945 until December 2018 for observational comparative and non-comparative studies and randomized trials examining any antibiotic option for CR-GNB. Studies were included if reporting microbiologically-confirmed infection caused by Acinetobacter baumannii, Enterobacteriaceae/Klebsiella spp., or Pseudomonas aeruginosa, reporting at least one of the study outcomes, and definitive antibiotic treatment. Carbapenem-resistance was defined as phenotypically-detected in vitro resistance to at least one of the following carbapenems: doripenem, ertapenem, imipenem, meropenem. Each antibiotic regimen was classified as "defined" when at least the molecular class(es) composing the regimen was detailed. Primary outcomes were 30-day and attributable mortality. Bayesian network meta-analysis (NMA) approach was selected for quantitative synthesis to explore feasibility of pooling data on antibiotic regimens. RESULTS: A total of 6306 records were retrieved and 134 studies including 11,546 patients were included: 54 studies were on Acinetobacter, 52 on Enterobacteriaceae/Klebsiella, 21 on mixed Gram-negative, and 7 on Pseudomonas. Nine (7%) were RCTs; 19 prospective cohorts (14%), 89 (66%) retrospective, and 17 (13%) case series. Forty-one studies (31%) were multicentric. Qualitative synthesis showed an heterogeneous and scattered reporting of key-clinical and microbiological variables across studies. Ninety-two distinct antibiotic regimens were identified with 47 of them (51%, 5863 patients) not reporting any details on numbers, type, dosage and in vitro activity of the included antibiotic molecules. The NMAs could not be performed for any of the selected outcome given the presence of too many disconnected components. CONCLUSION: The existing evidence is insufficient to allowing for the formulation of any evidence-based therapeutic recommendation for CR-GNB sepsis. Future studies must provide a standardized definition of antibiotic regimen to drive recommendations for using combination of antibiotics that can be reliably applied to clinical practice.

Assessment of COVID-19 progression on day 5 from symptoms onset.

BACKGROUND: A major limitation of current predictive prognostic models in patients with COVID-19 is the heterogeneity of population in terms of disease stage and duration. This study aims at identifying a panel of clinical and laboratory parameters that at day-5 of symptoms onset could predict disease progression in hospitalized patients with COVID-19. METHODS: Prospective cohort study on hospitalized adult patients with COVID-19. Patient-level epidemiological, clinical, and laboratory data were collected at fixed time-points: day 5, 10, and 15 from symptoms onset. COVID-19 progression was defined as in-hospital death and/or transfer to ICU and/or respiratory failure (PaO2/FiO2 ratio < 200) within day-11 of symptoms onset. Multivariate regression was performed to identify predictors of COVID-19 progression. A model assessed at day-5 of symptoms onset including male sex, age > 65 years, dyspnoea, cardiovascular disease, and at least three abnormal laboratory parameters among CRP (> 80 U/L), ALT (> 40 U/L), NLR (> 4.5), LDH (> 250 U/L), and CK (> 80 U/L) was proposed. Discrimination power was assessed by computing area under the receiver operating characteristic (AUC) values. RESULTS: A total of 235 patients with COVID-19 were prospectively included in a 3-month period. The majority of patients were male (148, 63%) and the mean age was 71 (SD 15.9). One hundred and ninety patients (81%) suffered from at least one underlying illness, most frequently cardiovascular disease (47%), neurological/psychiatric disorders (35%), and diabetes (21%). Among them 88 (37%) experienced COVID-19 progression. The proposed model showed an AUC of 0.73 (95% CI 0.66-0.81) for predicting disease progression by day-11. CONCLUSION: An easy-to-use panel of laboratory/clinical parameters computed at day-5 of symptoms onset predicts, with fair discrimination ability, COVID-19 progression. Assessment of these features at day-5 of symptoms onset could facilitate clinicians' decision making. The model can also play a role as a tool to increase homogeneity of population in clinical trials on COVID-19 treatment in hospitalized patients.

Controlling Nutritional Status score does not predict patients' overall survival or hepatocellular carcinoma recurrence after deceased donor liver transplantation.

BACKGROUND: The Controlling Nutritional Status (CONUT) score is a newly developed laboratory-derived immunonutritional score which has been validated as prognostic marker for survival and tumor recurrence in surgically treated patients with various tumor types, including hepatocellular carcinoma (HCC). The aim of the present study was to test the CONUT score performance in HCC patients treated with liver transplantation (LT). METHODS: A retrospective study on a bi-centers cohort of 280 HCC patients submitted to LT between 2006 and 2017 was performed. Indication to LT was limited to Milan criteria or UCSF criteria, defined by preoperative imaging. RESULTS: Median pre-LT CONUT score was 5 (interquartile range 3-7). Overall patients' survival at 1, 3, and 5 years was 84%, 76.6%, and 68.3%, respectively. Multivariate analysis showed that HCC recurrence (hazard ratio [HR] = 1.987, P = .012] and pre-LT neutrophil to lymphocyte ratio (NLR) (HR = 1.064, P = .003) were independent risk factors for reduced survival. Cumulative incidence of HCC recurrence at 1, 3, and 5 years was 5.1%, 11.5%, and 15.5%, respectively. Pre-LT platelet-to-lymphocyte ratio (PLR) (subdistribution hazard ratio [SHR] = 1.086, P = .044], tumor max diameter (SHR = 1.695, P < .001), and bilobar tumor distribution (SHR = 6.892, P = .006) were independent risk factors for tumor recurrence. The CONUT score did not show any prognostic value. CONCLUSIONS: The CONUT score did not predict poor survival or tumor recurrence in LT recipients.

Incremental value of FDG-PET/CT to monitor treatment response in infectious spondylodiscitis.

OBJECTIVE: To assess the added value of serial 2-deoxy-2-[18F]fluoro-D-glucose (FDG) uptake analysis in predicting clinical response to treatment in infectious spondylodiscitis (IS). We sought to analyze changes in quantitative FDG-PET/CT parameters among patients with clinical response or treatment failure and to compare the sensitivity and specificity of serial FDG-PET/CT and MRI in predicting treatment response in IS. MATERIALS AND METHODS: This retrospective study consisted of 68 FDG-PET/CT examinations in 34 patients performed before and after at least 2 weeks of antibiotic treatment. Serial MRI scans were available in 32 (94%) patients before and after treatment. FDG-avid lesions were quantified as maximum standardized uptake value (SUVmax), partial-volume corrected lesion metabolic volume (LMV), and partial-volume corrected lesion metabolic activity (LMA). RESULTS: All FDG-PET/CT parameters significantly decreased in patients with clinical improvement (31/34, 91%, P < 0.001), while patients with disease progression did not show FDG-PET/CT improvement. FDG uptake decrease was similar between patients undergoing early assessment (< 6 weeks) compared with those performing FDG-PET/CT after 6 weeks of treatment. SUVmax, LMV, and LMA decrease over time was 39.0%, 97.4%, and 97.1%, respectively. In predicting clinical responses, SUVmax reduction > 15% and > 25% showed 94% and 89% sensitivity and 67% and 100% specificity compared with 37% and 50% of MRI, respectively. Low degree of agreement with clinical response was shown for MRI compared with FDG-PET/CT parameters using the Cohen kappa coefficient. CONCLUSIONS: FDG-PET/CT monitoring is a valuable tool to predict clinical response to treatment in IS and has greater sensitivity and specificity compared with MRI.

Efficacy of Ceftazidime-Avibactam Salvage Therapy in Patients With Infections Caused by Klebsiella pneumoniae Carbapenemase-producing K. pneumoniae.

Background: Ceftazidime-avibactam (CAZ-AVI) has been approved in Europe for the treatment of complicated intra-abdominal and urinary tract infections, as well as hospital-acquired pneumonia, and for gram-negative infections with limited treatment options. CAZ-AVI displays in vitro activity against Klebsiella pneumoniae carbapenemase (KPC) enzyme producers, but clinical trial data on its efficacy in this setting are lacking. Methods: We retrospectively reviewed 138 cases of infections caused by KPC-producing K. pneumoniae (KPC-Kp) in adults who received CAZ-AVI in compassionate-use programs in Italy. Case features and outcomes were analyzed, and survival was then specifically explored in the large subcohort whose infections were bacteremic. Results: The 138 patients started CAZ-AVI salvage therapy after a first-line treatment (median, 7 days) with other antimicrobials. CAZ-AVI was administered with at least 1 other active antibiotic in 109 (78.9%) cases. Thirty days after infection onset, 47 (34.1%) of the 138 patients had died. Thirty-day mortality among the 104 patients with bacteremic KPC-Kp infections was significantly lower than that of a matched cohort whose KPC-Kp bacteremia had been treated with drugs other than CAZ-AVI (36.5% vs 55.8%, P = .005). Multivariate analysis of the 208 cases of KPC-Kp bacteremia identified septic shock, neutropenia, Charlson comorbidity index ≥3, and recent mechanical ventilation as independent predictors of mortality, whereas receipt of CAZ-AVI was the sole independent predictor of survival. Conclusions: CAZ-AVI appears to be a promising drug for treatment of severe KPC-Kp infections, especially those involving bacteremia.

Current role of oxazolidinones and lipoglycopeptides in skin and soft tissue infections.

PURPOSE OF REVIEW: An increase of skin and soft tissue infections involving Staphylococcus aureus has been reported in community and hospital settings. Methicillin resistance in S. aureus is associated with treatment failure and increased mortality. Recently, new antimicrobials with enhanced activity against methicillin-resistant Staph. aureus have been approved for the treatment of skin and soft tissue infections. Among these, novel oxazolidinones and lipoglycopeptides represent options with favorable pharmacokinetic characteristics and safety profiles. RECENT FINDINGS: Newly approved compounds include tedizolid, characterized by the availability of both oral and intravenous formulation and once daily administration and dalbavancin, a long-acting antimicrobial allowing for weekly administration. These new molecules present advantages, such as enhanced activity against multidrug-resistant Gram-positive bacteria and favorable safety profiles. SUMMARY: We have reviewed the pharmacokinetic characteristics and the implications for use in skin and soft tissue infections of tedizolid and dalbavancin. Advantages associated with the use of these compounds include the possibility for early patient discharge, reduced hospital length of stay, and outpatient treatment, with potential impact on morbidity, mortality, and overall health-care costs.

Early post-liver transplant surgical morbidity in HIV-infected recipients: risk factor for overall survival? A nationwide retrospective study.

The aim of the study was to analyse the risk factors for early surgical complications requiring relaparotomy and the related impact on overall survival (OS) in HIV-infected patients submitted to liver transplantation. Thus a retrospective investigation was conducted on a nationwide multicentre cohort of 157 HIV patients submitted to liver transplantation in six Italian Transplant Units between 2004 and 2014. An early relaparotomy was performed in 24.8% of cases and the underlying clinical causes were biliary leak (8.2%), bleeding (8.2%), intestinal perforation (4.5%) and suspect of vascular complications(3.8%). No differences in terms of prevalence for either overall or cause-specific early relaparotomies were noted when compared with a non-HIV control group, matched for MELD, recipient age, HCV-RNA positivity and HBV prevalence. While in the control group an early relaparotomy appeared a negative prognostic factor, such impact on OS was not noted in HIV recipients. Nonetheless increasing number of relaparotomies were associated with decreased survival. In multivariate analysis, preoperative refractory ascites and Roux-en-Y choledochojejunostomy reconstruction were significant risk factors for early relaparotomy. To conclude, in HIV liver transplanted patients, an increasing number of early relaparotomies because of surgical complications does negatively affect the OS. Preoperative refractory ascites reflecting a severe portal hypertension and a difficult biliary tract reconstruction requiring a Roux-en-Y choledochojejunostomy are associated with increased risk of early relaparotomy.

Treatment of Candida infections with fluconazole in adult liver transplant recipients: Is TDM-guided dosing adaptation helpful?

BACKGROUND: Fluconazole represents a common antifungal option for the treatment of Candida infections in liver transplant recipients. Although adequate antifungal exposure is known to correlate with favorable outcomes in patients with invasive candidiasis, therapeutic drug monitoring (TDM) of fluconazole is currently not recommended. METHODS: We conducted a retrospective study including adult liver transplant recipients receiving fluconazole for invasive candidiasis and undergoing TDM. We assessed the correlation between clinical variables, fluconazole trough plasma levels (Cmin ), and outcome. RESULTS: Twenty-seven patients (74% males; median age 57 years) were included. Abdominal candidiasis was the most frequent infection (56%). Median duration of fluconazole therapy was 17 days (IQR 9-21). Fluconazole median Cmin was 11.0 mg/L (range 2.4-30.6 mg/L). Five (19%) patients required TDM-guided fluconazole dose increase. All-cause in hospital mortality was 33%. Fluconazole Cmin >11 mg/L significantly correlated with clinical success (OR 8.78, 95% CI 1.13-67.8, P = 0.04). CONCLUSIONS: Our study identified decreased fluconazole Cmin as a factor associated with negative outcomes in liver transplant recipients with Candida infection. TDM of fluconazole may be advisable in this patient population.

Developing definitions for invasive fungal diseases in critically ill adult patients in intensive care units. Protocol of the FUNgal infections Definitions in ICU patients (FUNDICU) project.

BACKGROUND: The reliability of diagnostic criteria for invasive fungal diseases (IFD) developed for severely immunocompromised patients is questionable in critically ill adult patients in intensive care units (ICU). OBJECTIVES: To develop a standard set of definitions for IFD in critically ill adult patients in ICU. METHODS: Based on a systematic literature review, a list of potential definitions to be applied to ICU patients will be developed by the ESCMID Study Group for Infections in Critically Ill Patients (ESGCIP) and the ESCMID Fungal Infection Study Group (EFISG) chairpersons. The proposed definitions will be evaluated by a panel of 30 experts using the RAND/UCLA appropriateness methods. The panel will rank each of the proposed definitions on a 1-9 scale trough a dedicated questionnaire, in two rounds: one remote and one face-to-face. Based on their median rank and the level of agreement across panel members, selected definitions will be organised in a main consensus document and in an executive summary. The executive summary will be made available online for public comments. CONCLUSIONS: The present consensus project will seek to provide standard definitions for IFD in critically ill adult patients in ICU, with the ultimate aims of improving their clinical outcome and facilitating the comparison and generalizability of research findings.

When to switch to an oral treatment and/or to discharge a patient with skin and soft tissue infections.

PURPOSE OF REVIEW: Skin and soft tissue infections prevalence is increasing and represent a frequent cause of hospital admission. New guidelines have become available in order to better define these infections and their response to antimicrobial treatment. Gram-positive bacteria, in particular Staphylococcus aureus, remain the most frequently isolated pathogens in skin and soft tissue infections. To treat complicated forms and infections caused by drug-resistant bacteria, hospital admission and administration of intravenous antibiotics are often required, impacting on healthcare costs and patients' morbidity. RECENT FINDINGS: New therapeutic options offer efficacy against drug-resistant Gram-positive bacteria as well as potential to favor early patients' discharge, including the possibility for intravenous to oral switch and infrequent drug administration because of prolonged drug half-life. Although data from real-world studies on new antimicrobials is awaited, clinicians need clear direction on how to optimize the treatment of skin and soft tissue infections in order to avoid prolonged hospitalizations and extra costs. Early assessment of patient's clinical conditions and response to treatment appear useful in order to facilitate patients' discharge. SUMMARY: We have reported the evidence for early intravenous to oral switch and early hospital discharge for patients with skin and soft tissue infections. New therapeutic options that represent promising tools in promoting an optimized management of these infections have also been reviewed.

New antibiotics for ventilator-associated pneumonia.

PURPOSE OF REVIEW: Ventilator-associated pneumonia (VAP) caused by multidrug-resistant (MDR) bacteria represents a global emerging problem. Delayed prescription of an adequate treatment for VAP has been associated with higher morbidity and mortality. New molecules have been developed to face the need of compounds that are active against resistant Gram-positive and Gram-negative pathogens. The aim of this review is to summarize the current scenario of new therapeutic options for the treatment of VAP. RECENT FINDINGS: A number of new antibiotics with activity against MDR have been recently approved for the treatment of VAP, and other agents are under investigation. In this review, the authors summarize the current therapeutic options for the treatment of VAP that showed promising implications for clinical practice, including new compounds belonging to old antibiotic classes (e.g., ceftolozane/tazobactam, ceftazidime/avibactam meropenem/vaborbactam, imipenem/relebactam, tedizolid, cefiderocol, eravacycline, and plazomicin) and novel chemical classes, such as murepavadin. Nebulized antibiotics that are currently in development for the treatment of pneumonia in mechanically ventilated patients are also presented. SUMMARY: Newly approved and investigational drugs for the treatment of VAP are expected to offer many advantages for the management of patients with respiratory infections caused by MDR. Promising characteristics of new compounds include high activity against both methicillin-resistant Staphylococcus aureus and MDR Gram-negative bacteria and a favorable safety profile.

The role of dalbavancin in skin and soft tissue infections.

PURPOSE OF REVIEW: The increase of skin and soft tissue infections (SSTIs) represents a major concern both in community and in the hospital setting. Staphylococcus aureus is the most frequently isolated pathogen, and the rise in infections due to methicillin-resistant Staphylococcus aureus (MRSA) has been associated with inadequate antibiotic treatment and increased morbidity. RECENT FINDINGS: A number of new antimicrobials with activity against drug-resistant Gram-positive pathogens, including MRSA, have been recently approved for the treatment of SSTIs. New lipoglycopeptides, in particular dalbavancin, are long-acting antibiotics with potential for infrequent administration, offering the possibility for outpatient treatment and early hospital discharge. SUMMARY: Dalbavancin is a new lipoglycopeptide showing high activity against Gram-positive bacteria, including drug-resistant strains. Dalbavancin presents a distinctive pharmacokinetic profile with a terminal prolonged half-life of approximately 14 days. This characteristic allows once-weekly dosing interval, avoiding the need for daily dosing and offering an advantage over other compounds for potential use in the outpatient setting or to promote early hospital discharge. Dalbavancin has a favorable adverse effect profile and appears to be a promising new alternative for treatment of SSTIs. We have reviewed the pharmacokinetic properties of dalbavancin and the clinical evidence for its use in complicated SSTIs and other potential applications.

What has changed in the treatment of invasive candidiasis? A look at the past 10 years and ahead.

The treatment of invasive candidiasis has changed greatly in the past decade and must continue to evolve if we are to improve outcomes in this serious infection. A review of recent history may provide insights for the future. The morbidity and mortality of invasive candidiasis remain difficult to measure despite an obvious clinical burden. Current treatment guidelines now recommend echinocandins as first-line empirical treatment, with fluconazole as an acceptable alternative for selected patients, reflecting the efficacy demonstrated by echinocandins and increasing resistance observed with fluconazole. The selection of antifungal therapy now must consider not only resistance but also the shift in predominance from Candida albicans to non-albicans species, notably Candida glabrata. The recent emergence of Candida auris has been met with great interest, although the longer-term implications of this phenomenon remain unclear. The broad goal of treatment continues to be administration of safe, efficacious antifungal therapy as soon as possible. Diagnostic methods beyond traditional blood culture present an opportunity to shorten the time to an accurate diagnosis, and earlier treatment initiation based on prophylactic and empirical or pre-emptive strategies seeks to ensure timely therapeutic intervention. In addition, there are novel agents in the antifungal pipeline. These developments, as well as ongoing studies of dosing, toxicity and resistance development, are important items on the current research agenda and may play a role in future changes to the treatment of invasive candidiasis.

Risk stratification and treatment of ICU-acquired pneumonia caused by multidrug- resistant/extensively drug-resistant/pandrug-resistant bacteria.

PURPOSE OF REVIEW: Describe the risk factors and discuss the management of multidrug-resistant (MDR) bacteria responsible for pneumonia among critically ill patients, including methicillin-resistant Staphylococcus aureus, extended spectrum beta-lactamase-producing Enterobactericeae, carbapenem-resistant Enterobactericeae, multidrug resistant Pseudomonas aeruginosa, and Acinetobacter baumannii. RECENT FINDINGS: Multiple factors have been associated with infections because of MDR bacteria, including prolonged hospital stay, presence of invasive devices, mechanical ventilation, colonization with resistant pathogens, and use of broad-spectrum antibiotics. Management of these infections includes the prompt use of appropriate antimicrobial therapy, implementation of antimicrobial stewardship protocols, and targeted active microbiology surveillance. Combination therapy and novel molecules have been used for the treatment of severe infections caused by resistant bacteria. SUMMARY: The exponential increase of antimicrobial resistance among virulent pathogens currently represents one of the main challenges for clinicians in the intensive care unit. Knowledge of the local epidemiology, patient risk stratification, and infection-control policies remain key elements for the management of MDR infections. Results from clinical trials on new molecules are largely awaited.

A prognostic score for the resolution of bacteremia by Gram-negative bacteria resistant to carbapenems.

The management of bacteremia by carbapenem-resistant Gram-negative bacteria (CRGNB) necessitates a surrogate marker for response to treatment. We developed a prognostic score of bacteremia resolution using a test and a validation cohort. In the test cohort, five protein biomarkers were measured in serial daily serum samples from 39 patients with ventilator-associated pneumonia (VAP) and CRGNB bacteremia. Receiver operator characteristic curves were designed to identify cut-off of over-time changes that were associated with more than 80% specificity for resolution of bacteremia. The developed score was validated in a cohort of 24 patients mostly with primary bacteremia by carbapenem-resistant enterobacteria (CRE). Among the five tested biomarkers, only procalcitonin (PCT) was associated with resolution of bacteremia. More precisely, resolved bacteremia was considered if at least one of three situations occurred: (a) PCT on day 2 was decreased more than 30% and PCT on day 4 was below 0.5 ng/ml; (b) PCT on day 4 was decreased more than 40% and PCT on day 4 was below 0.5 ng/ml; and (c) PCT on day 2 was decreased more than 30% and PCT on day 4 was decreased more than 40%. Sensitivity, specificity, and positive and negative predictive values of the score were 66.7%, 83.3%, 90.0%, and 52.6% respectively. This score was fully validated (p values of comparison between the cohorts 0.623). The developed score is highly predictive of resolution of bacteremia by CRGNB. A prospective clinical study is mandatory to validate the results.

Ceftolozane/tazobactam for the treatment of MDR Pseudomonas aeruginosa left ventricular assist device infection as a bridge to heart transplant.

BACKGROUND: Ceftolozane/tazobactam (C/T) is a novel antibiotic with enhanced microbiological activity against multidrug-resistant (MDR) gram-negative bacteria, including MDR Pseudomonas aeruginosa. CASE REPORT: Five months after left ventricular assist device (LVAD) implantation, a 49-year old man developed fever and blood culture was positive for MDR P. aeruginosa, susceptible only to aminoglycosides, ciprofloxacin and colistin. A diagnosis of LVAD-related infection was made based on persistent bacteremia associated with moderate 18 F-fluorodeoxyglucose positron emission tomography/CT uptake in the left ventricular apex. Disk diffusion testing for C/T was performed (MIC 2 µg/mL) and intravenous antibiotic therapy with C/T and amikacin was started, with clinical and microbiological response. Initial conservative management with 6 weeks of systemic antibiotic therapy was attempted, but the patient relapsed one month after antibiotic discontinuation. Priority for transplantation was given and after 4 weeks of antibiotic therapy (C/T + amikacin), LVAD removal and heart transplant were performed, with no infection relapse. CONCLUSIONS: We reported the first off-label use of C/T in the management of MDR P. aeruginosa LVAD infection as a bridge to heart transplant. C/T has shown potent anti-pseudomonal activity and good safety profile making this drug as a good candidate for suppressive strategy in intravascular device-associated bloodstream infections caused by MDR P. aeruginosa.

Population pharmacokinetics of fluconazole in liver transplantation: implications for target attainment for infections with Candida albicans and non-albicans spp.

OBJECTIVES: The study aims to assess the population pharmacokinetics of fluconazole and the adequacy of current dosages and breakpoints against Candida albicans and non-albicans spp. in liver transplant (LT) patients. PATIENTS AND METHODS: Patients initiated i.v. fluconazole within 1 month from liver transplantation (LTx) for prevention or treatment of Candida spp. infections. Multiple assessments of trough and peak plasma concentrations of fluconazole were undertaken in each patient by means of therapeutic drug monitoring. Monte Carlo simulations were performed to define the probability of target attainment (PTA) with a loading dose (LD) of 400, 600, and 800 mg at day 1, 7, 14, and 28 from LTx, followed by a maintenance dose (MD) of 100, 200, and 300 mg daily of the pharmacokinetic/pharmacodynamic target of AUC24h/MIC ratio ≥ 55.2. RESULTS: Nineteen patients were recruited. A two-compartment model with first-order intravenous input and first-order elimination was developed. Patient's age and time elapsed from LTx were the covariates included in the final model. At an MIC of 2 mg/L, a LD of 600 mg was required for optimal PTAs between days 1 and 20 from LTx, while 400 mg was sufficient from days 21 on. A MD of 200 mg was required for patients aged 40-49 years old, while a dose of 100 mg was sufficient for patients aged ≥ 50 years. CONCLUSIONS: Fluconazole dosages of 100-200 mg daily may ensure optimal PTA against C. albicans, C. parapsilosis, and C. tropicalis. Higher dosages are required against C. glabrata. Estimated creatinine clearance is not a reliable predictor of fluconazole clearance in LT patients.