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Background: This study assesses the impact of fluconazole resistance on 30-day all-cause mortality and 1-year recurrence in patients with Candida parapsilosis bloodstream infections (BSI)., Methods: A multicenter retrospective study was performed at 3 hospitals in Italy and Spain between 2018 and 2022. Adult patients with positive blood cultures for C. parapsilosis who received appropriate targeted therapy with either echinocandins or fluconazole were included., Results: Among 457 patients, 196 (42.9%) had fluconazole-resistant C. parapsilosis (FLZR-CP) BSI and 261 (57.1%) had fluconazole-susceptible C. parapsilosis (FLZS-CP) BSI. All FLZR-CP patients received targeted echinocandins, while FLZS-CP patients received either echinocandins (60.5%) or fluconazole (39.5%). Unadjusted 30-day all-cause mortality rates were 28.6% for FLZR-CP and 28.4% for FLZS-CP (log-rank test, P = .998). In multivariable analysis, increased mortality was associated with age (adjusted hazard ratio [aHR] 1.03 per year; 95% confidence interval [CI], 1.01-1.05; P = .0005), solid tumor (aHR 1.91; 95% CI, 1.06-3.46; P = .0302), previous antifungal treatment (aHR 1.84; 95% CI, 1.12-3.10; P = .0192), and septic shock (aHR 2.39; 95% CI, 1.42-4.06; P = .0010), but not fluconazole resistance (aHR 1.00; 95% CI, .62-1.63; P = .9864) nor the type of initial antifungal therapy (aHR 1.46; 95% CI, .69-3.06; P = .3202). Propensity score-matched analysis showed no 30-day all-cause mortality difference between echinocandin-treated FLZR-CP and fluconazole-treated FLZS-CP patients (HR 0.81; 95% CI, .37-1.75; P = .5915). However, a higher 1-year recurrence risk was observed in FLZR-CP patients (odds ratio, 7.37; 95% CI, 2.11-25.80; P = .0018)., Conclusions: Our results suggest that fluconazole resistance is not associated with a higher mortality risk in patients with C. parapsilosis BSI, though 1-year recurrence rates were higher in the FLZR-CP group., Competing Interests: Potential  conflicts of interest. Outside the submitted work, A. V. reports personal fees for speaker/advisor from Pfizer Inc, Shionogi, Tillotts Pharma, Menarini, Gilead Italia, Mundipharma, Advanz pharma and MSD. Outside the submitted work, D. R. G. reports investigator-initiated grants from Pfizer Inc, Shionogi, BioMérieux, Tillotts Pharma, Menarini, and Gilead Italia, personal fees for speaker/advisor from Pfizer Inc, Menarini, BioMérieux, and Tillotts Pharma. Outside the submitted work, M. B. reports research grants and/or personal fees for advisor/consultant and/or speaker/chairman from Bayer, BioMérieux, Cidara, Cipla, Gilead, Menarini, MSD, Pfizer, and Shionogi. Outside the submitted work, J. S. G. has received speaker honoraria by Gilead, Menarini, and Pfizer; travel grant by AstraZeneca and was on the advisory board for Pfizer. Outside the submitted work, P. M. reports investigator-initiated grants from Pfizer Inc, Shionogi, Tillotts Pharma, Menarini, and Gilead. Outside the submitted work, V. D. P. reports payments for participation in a company sponsored speaker's bureau from A.d.a, consulting fee from Biorad, supports for attending meetings from Arrow Diagnostics. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2025. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Objectives: To determine the association of adequate empirical combination therapy (AECT) with 30-day all-cause mortality in patients with septic shock due to Pseudomonas aeruginosa bloodstream infections (BSI)., Methods: This multicentre, retrospective cohort study analysed data from 14 public hospitals in Italy, including all consecutive adult patients admitted during 2021-2022 with septic shock due to P. aeruginosa BSI. We compared the outcomes of patients receiving AECT to those on adequate empirical monotherapy (AEMT) using Cox regression analyses., Results: Of the 98 patients who received adequate empirical antibiotic treatment for septic shock due to P. aeruginosa BSI, 24 underwent AECT and 74 were given AEMT. AECT was associated with a lower 30-day all-cause mortality (25%, six out of 24) compared to AEMT (56.8%, 42 out of 74; P = 0.007). Multivariate Cox regression analysis indicated AECT as the only factor significantly associated with improved survival (aHR 0.30; 95% CI 0.12-0.71; P = 0.006). By contrast, the use of monotherapy or combination therapy in the definitive regimen did not influence mortality (aHR 0.73; 95% CI 0.25-2.14; P = 0.568)., Conclusions: AECT may be associated with reduced mortality compared to monotherapy in septic shock patients due to P. aeruginosa BSI. However, the administration of definitive adequate monotherapy or combination therapy yields similar outcomes, suggesting that once susceptibility is documented, switching to a single active in vitro drug is safe and feasible. Further studies are recommended to validate these findings., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Isavuconazole is first-line treatment of invasive aspergillosis. Therapeutic drug monitoring (TDM) is deemed not necessary, since most patients reached therapeutic levels (>1 mg/L) in large studies. Low levels were reported in some critically ill patients admitted to the ICU. The aim was to compare isavuconazole levels between critically ill and non-critically ill patients., Materials and Methods: Retrospective analysis of data from all patients treated with standard-dose isavuconazole between 1 January 2019 and 26 October 2022 was performed. The following data were collected: TDM results from the first 30 days of therapy; ward of admission; demographic and clinical characteristics; continuous renal replacement therapy; extracorporeal membrane oxygenation; and co-administered drugs., Results: Seventy-two patients (median age 65 years) and 188 TDM measurements (mean number of samples per patient 2.6 ± 1.7) were included; 33 (45.8%) were ICU patients (3 also had haematological disorders); 39 (54.2%) were non-ICU patients, of whom 31 had haematological disorders. In all patients, the mean isavuconazole blood level was 3.33 ± 2.26 mg/L. Significantly lower levels were observed in the ICU versus the non-ICU population: mean 2.02 ± 1.22 versus 4.15 ± 2.31 mg/L (P < 0.001). Significantly higher rates of subtherapeutic levels were observed in ICU patients compared with the non-ICU population: all determinations <2 mg/L in 33.3% versus 7.7%, and all determinations <1 mg/L in 12.1% versus 0%, respectively. Predictors of lower isavuconazole levels were admission to the ICU, BMI > 25 kg/m2, bilirubin > 1.2 mg/dL and the absence of haematological disorder., Conclusions: ICU patients had significantly lower isavuconazole blood levels compared to non-ICU population. The TDM of isavuconazole for efficacy should be performed in ICU., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Human metapneumovirus (hMPV) epidemiology, clinical characteristics and risk factors for poor outcome after allogeneic stem cell transplantation (allo-HCT) remain a poorly investigated area., Methods: This retrospective multicenter cohort study examined the epidemiology, clinical characteristics, and risk factors for poor outcomes associated with human metapneumovirus (hMPV) infections in recipients of allo-HCT., Results: We included 428 allo-HCT recipients who developed 438 hMPV infection episodes between January 2012 and January 2019. Most recipients were adults (93%). hMPV infections were diagnosed at a median of 373 days after allo-HCT. The infections were categorized as upper respiratory tract disease (URTD) or lower respiratory tract disease (LRTD), with 60% and 40% of cases, respectively. Patients with hMPV LRTD experienced the infection earlier in the transplant course and had higher rates of lymphopenia, neutropenia, corticosteroid use, and ribavirin therapy. Multivariate analysis identified lymphopenia and corticosteroid use (>30 mg/d) as independent risk factors for LRTD occurrence. The overall mortality at day 30 after hMPV detection was 2% for URTD, 12% for possible LRTD, and 21% for proven LRTD. Lymphopenia was the only independent risk factor associated with day 30 mortality in LRTD cases., Conclusions: These findings highlight the significance of lymphopenia and corticosteroid use in the development and severity of hMPV infections after allo-HCT, with lymphopenia being a predictor of higher mortality in LRTD cases., Competing Interests: Potential conflicts of interest. P. B. declares research grants from Neovii, Riemser, and Medac (to institution); advisory board membership for Novartis, Cellgene, Amgen, Medac, and Servier (personal and to institution); speakers bureau for Miltenyi, Jazz, Riemser, Novartis, and Amgen (to institution); and patent und royalties from Medac. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objectives: To assess the impact of carbapenem resistance on mortality in Klebsiella pneumoniae bloodstream infection (BSI) in the era of novel β-lactam/β-lactamase inhibitor combinations., Material and Methods: Retrospective study of patients with K. pneumoniae BSI between January and August 2020 in 16 centres (CARBANEW study within the MULTI-SITA project)., Results: Overall, 426 patients were included: 107/426 (25%) had carbapenem-resistant K. pneumoniae (CR-Kp) BSI and 319/426 (75%) had carbapenem-susceptible K. pneumoniae (CS-Kp) BSI. Crude cumulative 30 day mortality was 33.8% and 20.7% in patients with, respectively, CR-Kp BSI and CS-Kp BSI (P = 0.027). Carbapenemase production or carbapenemase-encoding genes were detected in 84/98 tested CR-Kp isolates (85.7%), mainly KPC (78/84; 92.9%). Ceftazidime/avibactam was the most frequently used appropriate therapy for CR-Kp BSI (80/107; 74.7%). In multivariable analyses, variables showing an unfavourable association with mortality after correction for multiple testing were age-adjusted Charlson comorbidity index (HR 1.20; 95% CI 1.10-1.31, P < 0.001) and Pitt score (HR 1.33; 95% CI 1.15-1.55, P < 0.001), but not carbapenem resistance (HR 1.28, 95% CI 0.74-2.22, P = 0.410). In a propensity score-matched analysis, there was no difference in mortality between patients appropriately treated with ceftazidime/avibactam for CR-Kp BSI and patients appropriately treated with other agents (mainly meropenem monotherapy or piperacillin/tazobactam monotherapy) for CS-Kp BSI (HR 1.07; 95% CI 0.50-2.29, P = 0.866)., Conclusions: Our results suggest that the increased mortality in CR-Kp BSI compared with CS-Kp BSI is not (or no longer) dependent on the type of therapy in areas where ceftazidime/avibactam-susceptible KPC-producing isolates are the most prevalent type of CR-Kp., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Severely immunocompromised patients are at risk for prolonged or relapsed Coronavirus Disease 2019 (COVID-19), leading to increased morbidity and mortality. We aimed to evaluate efficacy and safety of combination treatment in immunocompromised COVID-19 patients., Methods: We included all immunocompromised patients with prolonged/relapsed COVID-19 treated with combination therapy with 2 antivirals (remdesivir plus nirmatrelvir/ritonavir, or molnupiravir in case of renal failure) plus, if available, anti-spike monoclonal antibodies (mAbs), between February and October 2022. The main outcomes were virological response at day 14 (negative Severe Acute Respiratory Syndrome Coronavirus 2 [SARS-CoV-2] swab) and virological and clinical response (alive, asymptomatic, with negative SARS-CoV-2 swab) at day 30 and the last follow-up., Results: Overall, 22 patients (Omicron variant in 17/18) were included: 18 received full combination of 2 antivirals and mAbs and 4 received 2 antivirals only; in 20 of 22 (91%) patients, 2 antivirals were nirmatrelvir/ritonavir plus remdesivir. Nineteen (86%) patients had hematological malignancy, and 15 (68%) had received anti-CD20 therapy. All were symptomatic; 8 (36%) required oxygen. Four patients received a second course of combination treatment. The response rate at day 14, day 30, and last follow-up was 75% (15/20 evaluable), 73% (16/22), and 82% (18/22), respectively. Day 14 and 30 response rates were significantly higher when combination therapy included mAbs. Higher number of vaccine doses was associated with better final outcome. Two patients (9%) developed severe side effects (bradycardia leading to remdesivir discontinuation and myocardial infarction)., Conclusions: Combination therapy including 2 antivirals (mainly remdesivir and nirmatrelvir/ritonavir) and mAbs was associated with high rate of virological and clinical response in immunocompromised patients with prolonged/relapsed COVID-19., Competing Interests: Potential conflicts of interest. E. A. reports research grants and/or personal fees for advisor/consultant and/or speaker/chairman from Vertex Pharmaceuticals and Celgene (Bristol-Myers Squibb), Vifor Pharma, Novartis, Blue Bird Bio, Menarini Stemline, Glaxo, Regeneron, Gilead, and Novartis. M. B. reports research grants and/or personal fees for advisor/consultant and/or speaker/chairman from Bayer, bioMérieux, Cidara, Cipla, Gilead, Menarini, MSD, Pfizer, and Shionogi. D. R. G. reports research grants and/or personal fees for advisor/consultant and/or speaker/chairman from Gilead, Shionogi, Pfizer, and Tillotts Pharma. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: Molecular analysis (MA) on heart valve (HV) improves the microbiologic diagnosis of infectious endocarditis (IE). The main drawback of MA is the lack of antimicrobial susceptibility information., Methods: We conducted a prospective cohort observational study of consecutive adult patients from April 2012 to May 2021 who underwent valve surgery at our hospital. The performance of MA, blood cultures (BC) and valve cultures (VC), and the diagnostic and therapeutic impact of MA were evaluated. Molecular antibiogram results were compared to culture-based antimicrobial susceptibility testing (AST)., Results: A total of 137 patients with definite IE and 52 patients with no IE were enrolled in the study. Among IE cases BC, VC, and MA were positive in 75 (55%), 30 (22%), and 120 (88%) of IE cases, respectively. Among 62 cases of BC-negative IE (BCNE), 57 achieved diagnosis with MA. MA led to a change of antimicrobial therapy in 92% of BCNE. MA was negative in 100% of patients with no IE. Molecular antibiogram performed on 17 valve specimens that resulted positive for pathogens potential carrier of genes encoding for multidrug resistant mechanisms showed 100% concordance with AST., Conclusions: MA showed a high specificity and sensitivity in etiological diagnosis of IE. Molecular antibiogram could overcome the major limitation of MA that is the lack of susceptibility testing. We advocate for the inclusion of MA among diagnostic criteria for IE and for a more extensive use of molecular antibiogram when the culture result is negative, and MA is the only positive test., Competing Interests: Potential conflicts of interest. The authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: Nocardiosis is rare after hematopoietic cell transplantation (HCT). Little is known regarding its presentation, management, and outcome in this population., Methods: This retrospective international study reviewed nocardiosis episodes in HCT recipients (1/1/2000-31/12/2018; 135 transplant centers; 33 countries) and described their clinical, microbiological, radiological, and outcome characteristics., Results: We identified 81 nocardiosis episodes in 74 allo- and 7 auto-HCT recipients. Nocardiosis occurred a median of 8 (IQR: 4-18) months post-HCT. The most frequently involved organs were lungs (70/81; 86%) and brain (30/81; 37%); 29 (36%) patients were afebrile; 46/81 (57%) had disseminated infections. The most common lung imaging findings were consolidations (33/68; 49%) or nodules (32/68; 47%); brain imaging findings were multiple brain abscesses (19/30; 63%). Ten of 30 (33%) patients with brain involvement lacked neurological symptoms. Fourteen of 48 (29%) patients were bacteremic. Nocardia farcinica was the most common among molecularly identified species (27%; 12/44). Highest susceptibility rates were reported to linezolid (45/45; 100%), amikacin (56/57; 98%), trimethoprim-sulfamethoxazole (57/63; 90%), and imipenem (49/57; 86%). One-year and last follow-up (IQR: 4-42.5 months) all-cause mortality were 40% (32/81) and 52% (42/81), respectively. In the multivariable analysis, underlying disease not in complete remission (HR: 2.81; 95% CI: 1.32-5.95) and prior bacterial infection (HR: 3.42; 95% CI: 1.62-7.22) were associated with higher 1-year all-cause mortality., Conclusions: Nocardiosis is a late post-HCT infection usually manifesting as a pulmonary disease with frequent dissemination, brain infection, and bacteremia. Brain imaging should be performed in HCT recipients with nocardiosis regardless of neurological symptoms. Overall mortality is high., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: Little is known about characteristics of seasonal human coronaviruses (HCoVs) (NL63, 229E, OC43, and HKU1) after allogeneic stem cell transplantation (allo-HSCT)., Methods: This was a collaborative Spanish and European bone marrow transplantation retrospective multicenter study, which included allo-HSCT recipients (adults and children) with upper respiratory tract disease (URTD) and/or lower respiratory tract disease (LRTD) caused by seasonal HCoV diagnosed through multiplex polymerase chain reaction assays from January 2012 to January 2019., Results: We included 402 allo-HSCT recipients who developed 449 HCoV URTD/LRTD episodes. Median age of recipients was 46 years (range, 0.3-73.8 years). HCoV episodes were diagnosed at a median of 222 days after transplantation. The most common HCoV subtype was OC43 (n = 170 [38%]). LRTD involvement occurred in 121 episodes (27%). HCoV infection frequently required hospitalization (18%), oxygen administration (13%), and intensive care unit (ICU) admission (3%). Three-month overall mortality after HCoV detection was 7% in the whole cohort and 16% in those with LRTD. We identified 3 conditions associated with higher mortality in recipients with LRTD: absolute lymphocyte count <0.1 × 109/mL, corticosteroid use, and ICU admission (hazard ratios: 10.8, 4.68, and 8.22, respectively; P < .01)., Conclusions: Seasonal HCoV after allo-HSCT may involve LRTD in many instances, leading to a significant morbidity., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Diagnosis of invasive aspergillosis (IA) is challenging, particularly in high-risk patients with lung lesions other than typical according to 2008-EORTC/MSG criteria. Even if microbiology is positive, they still remain unclassified according to 2008-EORTC/MSG. Quantitative polymerase chain reaction (qPCR) provides new mycological documentation of IA. This retrospective study assessed Aspergillus fumigatus real time qPCR (MycoGENIE®) in BAL to diagnose IA and identify azole-resistant strains. Clinical, radiological, and microbiological data from 114 hematology patients (69% HSCT recipients; 29% on mould active agents) from years 2012-2017 were collected; and 123 BAL samples were tested with qPCR (cutoff: Ct < 40) and galactomannan (GM, Platelia®, cutoff: 0.5 ODI). Patients were classified as proven/probable, possible, and no-IA. "Atypical-IA" referred to patients with lesions other than typical according to 2008-EORTC/MSG and positive mycology. Proven IA was diagnosed in two cases (1.6%), probable in 28 (22.8%), possible in 27 (22%), atypical in 14 (11.4%). qPCR was positive in 39 samples (31.7%). Sensitivity and specificity of qPCR for proven/probable IA (vs no-IA; atypical-IA excluded) were 40% (95% confidence interval [CI]: 23-59) and 69% (95%CI: 55-81), respectively. Sensitivity of qPCR was higher when combined with GM (83%, 95%CI: 65-94) and in those receiving mould-active agents at BAL (61%, 95%CI: 32-86). One sample had TR34/L98H mutation. In conclusion, in high-risk hematology patients with various lung lesions, A. fumigatus qPCR in BAL contributes to diagnosing IA, particularly if combined with GM and in patients receiving mould-active agents might allow detecting azole-resistant mutations in culture negative samples., (© The Author(s) 2019. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Background: Isavuconazole is the newest triazole antifungal approved for the treatment of invasive aspergillosis (IA) and invasive mucormycosis in adult patients., Objectives: To characterize the assessment of the blood levels of isavuconazole and their association with efficacy and toxicity., Methods: From January 2017 to May 2018, blood samples obtained from patients receiving isavuconazole were analysed for therapeutic drug monitoring. Factors influencing the blood concentrations of isavuconazole, such as weight, length of treatment, route of administration and results of selected liver function tests, were analysed in univariate and multivariate models. The receiver operating characteristic (ROC) curve was analysed to detect the best cut-off for isavuconazole toxicity., Results: A total of 264 isavuconazole blood concentrations in 19 patients were analysed. The median value of isavuconazole concentration in all patients during the first 30 days of therapy was 3.69 mg/L (range 0.64-8.13 mg/L). A linear increase of 0.032 mg/L (range 0.023-0.041 mg/L) for each day of treatment (P = 0.002) was observed. In multivariate analysis the association between the length of treatment and higher levels of isavuconazole (P < 0.001) and higher serum GGT and lower isavuconazole levels (P = 0.001) was confirmed. Adverse events, mainly gastrointestinal, were reported in six patients (31.6%). Based on time-dependent and fixed-time ROC curve analysis, 4.87 mg/L and 5.13 mg/L, respectively, were the identified thresholds for toxicity., Conclusions: Isavuconazole was efficacious and well tolerated. Side effects, mainly gastrointestinal, were associated with prolonged administration and high serum levels., (© The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: This intercontinental study aimed to study gram-negative rod (GNR) resistance in hematopoietic stem cell transplantation (HSCT)., Methods: GNR bacteremias occurring during 6 months post-HSCT (February 2014-May 2015) were prospectively collected, and analyzed for rates and risk factors for resistance to fluoroquinolones, noncarbapenem anti-Pseudomonas β-lactams (noncarbapenems), carbapenems, and multidrug resistance., Results: Sixty-five HSCT centers from 25 countries in Europe, Australia, and Asia reported data on 655 GNR episodes and 704 pathogens in 591 patients (Enterobacteriaceae, 73%; nonfermentative rods, 24%; and 3% others). Half of GNRs were fluoroquinolone and noncarbapenem resistant; 18.5% carbapenem resistant; 35.2% multidrug resistant. The total resistance rates were higher in allogeneic HSCT (allo-HSCT) vs autologous HSCT (auto-HSCT) patients (P < .001) but similar in community-acquired infections. Noncarbapenem resistance and multidrug resistance were higher in auto-HSCT patients in centers providing vs not providing fluoroquinolone prophylaxis (P < .01). Resistance rates were higher in southeast vs northwest Europe and similar in children and adults, excluding higher fluoroquinolone- and β-lactam/β-lactamase inhibitor resistance rates in allo-HSCT adults. Non-Klebsiella Enterobacteriaceae were rarely carbapenem resistant. Multivariable analysis revealed resistance risk factors in allo-HSCT patients: fluoroquinolone resistance: adult, prolonged neutropenia, breakthrough on fluoroquinolones; noncarbapenem resistance: hospital-acquired infection, breakthrough on noncarbapenems or other antibiotics (excluding fluoroquinolones, noncarbapenems, carbapenems), donor type; carbapenem resistance: breakthrough on carbapenem, longer hospitalization, intensive care unit, previous other antibiotic therapy; multidrug resistance: longer hospitalization, breakthrough on β-lactam/β-lactamase inhibitors, and carbapenems. Inappropriate empiric therapy and mortality were significantly more common in infections caused by resistant bacteria., Conclusions: Our data question the recommendation for fluoroquinolone prophylaxis and call for reassessment of local empiric antibiotic protocols. Knowledge of pathogen-specific resistance enables early appropriate empiric therapy. Monitoring of resistance is crucial., Clinical Trials Registration: NCT02257931., (© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Objectives: Galactomannan (GM) testing is extremely useful for diagnosing invasive aspergillosis in high-risk patients, but false-positive results have been reported in patients treated with piperacillin/tazobactam. The aims of this study are to test if the recent piperacillin/tazobactam (Tazocin™; Pfizer) preparation still contains GM, and if serum GM positivity in haematopoietic stem cell transplant (HSCT) recipients receiving piperacillin/tazobactam can be attributed to this treatment., Patients and Methods: Serum samples obtained from 1 October 2009 to 31 October 2010 from HSCT recipients for GM testing were analysed. The difference in the rate of positive results (defined as GM ≥ 0.5) in patients receiving and not receiving piperacillin/tazobactam was evaluated. Piperacillin/tazobactam vials from randomly selected batches were tested., Results: Of 1606 samples drawn in the absence of piperacillin/tazobactam therapy, 25 (1.6%) tested positive for GM versus 10 of 394 samples (2.5%) drawn while on piperacillin/tazobactam (P = 0.18). The median GM result of samples drawn on piperacillin/tazobactam was slightly higher than that of samples drawn in the absence of piperacillin/tazobactam (0.141 versus 0.122; P < 0.001). All 90 piperacillin/tazobactam vials from 30 randomly selected batches tested negative for GM, with a median GM value of 0.057 (range: 0.011-0.320)., Conclusions: Although some residual GM might still be present in piperacillin/tazobactam, currently available brand piperacillin/tazobactam preparations seem no longer responsible for false-positive GM results.