Guidance of empirical antimicrobial therapy by surveillance cultures in high-risk neutropenic patients: a retrospective cohort study.

BACKGROUND: In neutropenic patients, bloodstream infections (BSI) significantly contribute to morbidity and mortality. Appropriate empirical antibiotic therapy (EAT) of BSI is essential, at the same time overconsumption of very broad-spectrum antibiotics should be avoided. We investigated: (1) whether surveillance cultures can predict BSI with third-generation cephalosporin -resistant Enterobacterales and Pseudomonas aeruginosa (3GC-R), (2) the effect of inappropriate empirical antimicrobial therapy (IEAT) on clinical outcome and (3) the potential reduction of carbapenem use when using surveillance cultures to guide therapy. METHODS: Retrospective study of adult patients with haematological malignancies with febrile episodes during chemotherapy-induced high-risk neutropenia in whom surveillance cultures were collected weekly. IEAT was defined as the absence of in vitro susceptibility of blood-isolates to the administered EAT. Clinical outcome (ICU admission and death) was evaluated within 30 days. RESULTS: A total of 673 febrile episodes occurred among 372 high-risk neutropenic patients. BSI was present in 20.1% (135/673), of which 25.9% (35/135) were due to Enterobacterales and P. aeruginosa. Of these, 17/35 were 3GC-R and 70.6% (12/17) were preceded by 3GC-R colonization. Negative predictive value of surveillance cultures for 3GC-R BSI was 99.1%. IEAT due to (3GC-R) BSI was not significantly associated with clinical outcome. Using surveillance cultures to guide EAT could potentially reduce carbapenem use by 82.8%, when compared to standard EAT with carbapenem. CONCLUSIONS: This retrospective analysis shows that in patients with high-risk neutropenia, surveillance cultures can potentially reduce the use of carbapenems with infrequent IEAT for 3GC-R BSI and no negative impact on clinical outcome.

Third-generation cephalosporin resistant gram-negative bacteraemia in patients with haematological malignancy; an 11-year multi-centre retrospective study.

OBJECTIVES: Among patients with haematological malignancy, bacteraemia is a common complication during chemotherapy-induced neutropenia. Resistance of gram-negative bacteria (GNB) to third-generation cephalosporins (3GC) is increasing. In order to explore the value of using surveillance cultures to guide empirical treatment e.g. choosing between carbapenem versus ceftazidime- we aimed to assess the distribution of pathogens causing bacteraemia in patients with haematological malignancy, and the proportion of 3GC-resistant GNB (3GC-R GNB) bacteraemia that was preceded by 3GC-R GNB colonization. METHODS: Using 11 years of data (2008-2018) from the Dutch national antimicrobial resistance surveillance system, we assessed the prevalence of 3GC-R GNB in episodes of bacteraemia, and the proportion of 3GC-R GNB bacteraemia that was preceded by 3GC-R GNB colonization. Colonization was defined as availability of any GNB surveillance isolate in the year before, independent of the causative micro-organism (time-paired isolates). RESULTS: We included 3887 patients, representing 4142 episodes of bacteraemia. GNB were identified in 715/4142 (17.3%), of which 221 (30.9%) were 3GC-R GNB. In 139 of these 221 patients a time-paired surveillance culture was available. In 76.2% (106/139) of patients these surveillance cultures already showed 3GC-R GNB isolates in the year prior to the culture date of the 3GC-R GNB positive blood isolate. CONCLUSIONS: This multi-centre study shows that in patients with haematological malignancy, the majority of 3GC-R GNB bacteraemia is preceded by 3GC-R GNB colonization. Prospective clinical studies are needed to assess the safety and benefits of the use of surveillance-cultures to guide empirical therapy to restrict the empirical use of carbapenems in this population.

Short versus extended treatment with a carbapenem in patients with high-risk fever of unknown origin during neutropenia: a non-inferiority, open-label, multicentre, randomised trial.

BACKGROUND: Early antibiotic discontinuation has been advocated in haematology patients with fever of unknown origin during chemotherapy-induced neutropenia, but its safety is unknown. We aimed to assess if short treatment with carbapenems is non-inferior to extended treatment. METHODS: This non-inferiority, open-label, multicentre, randomised trial was done in six hospitals in the Netherlands. Adult patients (≥18 years) who were treated with intensive chemotherapy or haematopoietic stem-cell transplantation (HSCT) for a haematological malignancy, and had fever of unknown origin during high-risk neutropenia (<0·5 × 109/L expected for ≥7 days) were eligible. After onset of fever, patients received either 500 mg intravenous imipenem-cilastatin four times a day or 1000 mg intravenous meropenem three times a day. Between 48 h and 72 h of treatment, participants were randomly assigned (1:1) by a computer-generated sequence to receive a short-term (72 h [60-84]; short treatment group) or extended (≥9 days until being afebrile for 5 days or neutrophil recovery; extended treatment group) carbapenem regimen. The composite primary endpoint was treatment failure, defined as recurrent fever or a carbapenem-sensitive infection between day 4 and day 9 and septic shock or respiratory failure or death from day 4 until neutrophil recovery. The study was designed to assess the non-inferiority of the short treatment compared with the extended treatment regimen, with a non-inferiority margin of 10%. The primary outcome was adjudicated by an independent outcome committee, who were masked to treatment allocation, and was analysed in the intention-to-treat and per-protocol populations. The trial is completed and registered with ClinicalTrials.gov, NCT02149329. FINDINGS: Between Dec 1, 2014, and July 1, 2019, 281 patients were included in the intention-to-treat analysis: 144 (51%) patients were assigned to the short treatment group and 137 (49%) to the extended treatment group. Median age was 59 years (IQR 52-65); 109 (39%) patients were women and 172 (61%) were men; 205 (73%) patients received HSCT. In the intention-to-treat analysis, 28 (19%) of 144 patients in the short treatment group versus 21 (15%) of 137 patients in the extended treatment group had treatment failure (adjusted risk difference [ARD] 4·0% [90% CI -1·7% to 9·7%]; p=0·25). In the per-protocol analysis (n=225), 24 (23%) of 104 patients in the short treatment group and 19 (16%) of 121 patients in the extended treatment group had treatment failure (ARD 7·3% [0·3% to 14·9%]; p=0·11). The most common grade 3-5 infection-related adverse events were mucositis (23 [20%] of 114 adverse events in the short treatment group vs 28 [29%] of 98 adverse events in the extended treatment group), fever of unknown origin (20 [18%] vs 16 [16%] events), and bacteraemia (15 [13%] vs 13 [13%] events). The number of serious adverse events were higher in the short treatment group (23 [16%] of 144 patients) than in the extended treatment group (14 [10%] of 137 patients), due to an increased rate of readmission (17 [12%] patients in the short treatment group vs ten [7%] in the extended treatment group). Death before 30 days after neutrophil recovery occurred in five (3%) participants in the short treatment group: two due to progressive leukaemia, two due to candidaemia, and one due to Enterococcus faecium bacteraemia and drug-induced pneumonitis. One (1%) patient died in the extended treatment group due to candidaemia. None of the deaths were related to carbapenem-sensitive infections. INTERPRETATION: Early discontinuation of carbapenem treatment in patients with febrile neutropenia of unknown origin does not result in increased treatment failure. Our study supports short treatment if patients are afebrile after 3 days of carbapenem treatment. However, because secondary analyses suggested that serious adverse events and all-cause mortality occurred more often in patients who are persistantly febrile the short treatment group, we recommend vigilance for non-susceptible pathogens and early resumption of empirical therapy in patients who are deteriorating. FUNDING: The Netherlands Organisation for Health Research and Development and Fonds NutsOhra.

The impact of the updated EORTC/MSG criteria on the classification of hematological patients with suspected invasive pulmonary aspergillosis.

OBJECTIVES: Our aim was to evaluate the effect of the updated European Organization for Research and Treatment of Cancer (EORTC) and Mycoses Study Group 2019 definitions for invasive pulmonary aspergillosis (IPA) on patient classification and the related all-cause 12-week mortality. METHODS: In this retrospective cohort study from our tertiary care centre, we reclassified patients with haematological malignancy who underwent bronchoalveolar lavage between 2014 and 2019 for suspected IPA using the novel EORTC 2019 criteria. We performed receiver operating characteristic curve analysis to define the optimal cut-off for positive PCR and galactomannan and present survival analyses and their possible association with these diagnostic criteria through post hoc comparisons with log rank and Cox regression. RESULTS: From 323 episodes of suspected IPA in 282 patients, 73 were reclassified: 31 (42.5%) from possible to probable IPA, 5 (6.8%) from EORTC criteria not met to probable IPA, and 37 (50.7%) from EORTC criteria not met to possible IPA. Probable IPA increased therefore 11.1% (64/323, 19.8% to 100/323, 30.9%), mostly due to positive PCR (31/36, 86.1%). There was no difference in mortality between newly defined possible and probable IPA (log rank p = 0.950). Mortality was higher in probable cases with lower cycle thresholds (Ct values) versus higher Ct values (p = 0.004). Receiver operating characteristic curve analysis showed an optimal Ct value cut-off of 36.8 with a sensitivity of 75% (95% CI 64.9%-85.1%) and a specificity of 61.7% (95% CI 53.5-69.9) for 12-week mortality. DISCUSSION: The new EORTC criteria led to 11.1% more probable IPA diagnoses, mostly due to Aspergillus PCR. Restricting positive PCR to below a certain threshold might improve the discrimination of the new EORTC IPA categories for mortality.

Normal hematopoietic stem cells within the AML bone marrow have a distinct and higher ALDH activity level than co-existing leukemic stem cells.

Persistence of leukemic stem cells (LSC) after chemotherapy is thought to be responsible for relapse and prevents the curative treatment of acute myeloid leukemia (AML) patients. LSC and normal hematopoietic stem cells (HSC) share many characteristics and co-exist in the bone marrow of AML patients. For the development of successful LSC-targeted therapy, enabling eradication of LSC while sparing HSC, the identification of differences between LSC and HSC residing within the AML bone marrow is crucial. For identification of these LSC targets, as well as for AML LSC characterization, discrimination between LSC and HSC within the AML bone marrow is imperative. Here we show that normal CD34+CD38- HSC present in AML bone marrow, identified by their lack of aberrant immunophenotypic and molecular marker expression and low scatter properties, are a distinct sub-population of cells with high ALDH activity (ALDH(bright)). The ALDH(bright) compartment contains, besides normal HSC, more differentiated, normal CD34+CD38+ progenitors. Furthermore, we show that in CD34-negative AML, containing solely normal CD34+ cells, LSC are CD34- and ALDH(low). In CD34-positive AML, LSC are also ALDH(low) but can be either CD34+ or CD34-. In conclusion, although malignant AML blasts have varying ALDH activity, a common feature of all AML cases is that LSC have lower ALDH activity than the CD34+CD38- HSC that co-exist with these LSC in the AML bone marrow. Our findings form the basis for combined functionally and immunophenotypically based identification and purification of LSC and HSC within the AML bone marrow, aiming at development of highly specific anti-LSC therapy.