Utilization of cefepime therapeutic drug monitoring in febrile neutropenia patients with hematologic malignancies.

INTRODUCTION: Cefepime is a fourth-generation cephalosporin and is a workhorse for the empiric treatment of febrile neutropenia (FN). Beta-lactam therapeutic drug monitoring (TDM) has emerged as a dose optimization strategy in patient populations with altered kinetics. Prior literature has demonstrated that patients with FN exhibit augmented renal clearance which may lead to subtherapeutic drug concentrations with standard dosing regimens. The aim of this study was to evaluate pharmacokinetic/pharmacodynamic (PK/PD) target attainment and clinical outcomes in patients with hematologic malignancies and FN who were treated empirically with cefepime. METHODS: This was a prospective, single-center study of adults with hematologic malignancies and FN admitted to the inpatient unit. The primary outcome was PK/PD target attainment (defined as 100% free time greater than minimum inhibitory concentration (100% fT > MIC)). Secondary clinical outcomes were time to defervescence, time to ANC recovery, in-hospital mortality, and cefepime failure. RESULTS: There were 55 patients in our study. Forty-three (78%) patients achieved the primary outcome of PK/PD target attainment. The mean time to defervescence was similar between those that achieved PK/PD target attainment and those that did not (95% CI -0.75 to 1.25, p = 0.62). CONCLUSIONS: This study showed that standard cefepime dosing in patients with hematologic malignancies and FN does not result in achievement of 100% fT > MIC in all patients. Patients in the group that did not achieve PK/PD target attainment were younger with increased creatinine clearance, indicating that cefepime TDM may be especially beneficial in these patients.

Evaluating the incidence of engraftment syndrome with different melphalan formulations in adult multiple myeloma and immunoglobulin light chain amyloidosis patients undergoing autologous hematopoietic cell transplantation.

BACKGROUND: Engraftment syndrome (ES) is a common complication of autologous hematopoietic cell transplantation (HCT). The difference in incidence of ES between melphalan formulations has not been widely reported throughout the literature and would allow for a more comprehensive understanding of the advantages and disadvantages of both melphalan formulations. PATIENTS AND METHODS: This retrospective, single-center, observational study evaluated 83 adult multiple myeloma and immunoglobulin light chain amyloidosis patients who received either propylene glycol-containing (PG) or propylene glycol-free (PG-free) melphalan 140 mg/m2 as single-agent conditioning chemotherapy for autologous HCT from May 31, 2015 to May 31, 2019. The primary outcome was to assess the incidence of ES, as defined using the Maiolino criteria, with both melphalan formulations. Secondary outcomes included an analysis of potential risk factors for the development of ES, as well as an evaluation of overall length of stay (LOS). RESULTS: The incidence of ES for PG and PG-free melphalan did not differ significantly, 14/39 (35.9%) and 12/44 (27.3%) (P = 0.4), respectively. No potential risk factors for ES were identified on multivariate logistic regression analysis. A statistically significant difference in number of days to engraftment was identified for PG and PG-free melphalan, 15.56 vs. 13.82 days (P = 0.01), respectively; although, this did not translate to a decrease in LOS, 19.9 vs. 18.59 days (P = 0.14). CONCLUSIONS: The incidence of ES did not differ significantly between melphalan formulations. Future research is needed to determine whether the faster time to engraftment seen with PG-free melphalan may translate to a decrease in LOS.

Impact of the CYP2C19 genotype on voriconazole exposure in adults with invasive fungal infections.

OBJECTIVES: Voriconazole, a first-line agent for the treatment of invasive fungal infections (IFIs), is metabolized by CYP2C19. A significant proportion of patients fail to achieve therapeutic trough concentrations with standard weight-based voriconazole dosing, placing them at increased risk for treatment failure, which can be life threatening. We sought to test the association between the CYP2C19 genotype and subtherapeutic voriconazole concentrations in adults with IFIs. PATIENT AND METHODS: Adults receiving weight-based voriconazole dosing for the treatment of IFIs were genotyped for the CYP2C19*2, *3, and *17 polymorphisms, and CYP2C19 metabolizer phenotypes were inferred. Steady-state voriconazole trough plasma concentrations and the prevalence of subtherapeutic troughs (<2 mg/l) were compared between patients with the CYP2C19*17/*17 (ultrarapid metabolizer, UM) or *1/*17 (rapid metabolizer, RM) genotype versus those with other genotypes. Logistic regression, adjusting for clinical factors, was performed to estimate the odds of subtherapeutic concentrations. RESULTS: Of 70 patients included (mean age 52.5±18 years), 39% were RMs or UMs. Compared with patients with the other phenotypes, RMs/UMs had a lower steady-state trough concentration (4.26±2.2 vs. 2.86±2.3, P=0.0093) and a higher prevalence of subtherapeutic troughs (16 vs. 52%, P=0.0028), with an odds ratio of 5.6 (95% confidence interval: 1.64-19.24, P=0.0044). CONCLUSION: Our findings indicate that adults with the CYP2C19 RM or UM phenotype are more likely to have subtherapeutic concentrations with weight-based voriconazole dosing. These results corroborate previous findings in children and support the potential clinical utility of CYP2C19 genotype-guided voriconazole dosing to avoid underexposure in RMs and UMs.

Amoeba host-Legionella synchronization of amino acid auxotrophy and its role in bacterial adaptation and pathogenic evolution.

Legionella pneumophila, the causative agent of Legionnaires' disease, invades and proliferates within a diverse range of free-living amoeba in the environment, but upon transmission to humans, the bacteria hijack alveolar macrophages. Intracellular proliferation of L. pneumophila in two evolutionarily distant hosts is facilitated by bacterial exploitation of conserved host processes that are targeted by bacterial protein effectors injected into the host cell. A key aspect of microbe-host interaction is microbial extraction of nutrients from the host, but understanding of this is still limited. AnkB functions as a nutritional virulence factor and promotes host proteasomal degradation of polyubiquitinated proteins generating gratuitous levels of limiting host cellular amino acids. Legionella pneumophila is auxotrophic for several amino acids including cysteine, which is a metabolically preferred source of carbon and energy during intracellular proliferation, but is limiting in both amoebae and humans. We propose that synchronization of bacterial amino acids auxotrophy with the host is a driving force in pathogenic evolution and nutritional adaptation of L. pneumophila and other intracellular bacteria to life within the host cell. Understanding microbial strategies of nutrient generation and acquisition in the host will provide novel antimicrobial strategies to disrupt pathogen access to essential sources of carbon and energy.

Evaluation of methylene blue, thiamine, and/or albumin in the prevention of ifosfamide-related neurotoxicity.

SUMMARY: A serious adverse effect that can limit the utility of ifosfamide is neurotoxicity, known as ifosfamide-induced encephalopathy (IIE). Information regarding the usefulness of prophylactic administration of methylene blue, thiamine, and albumin to reduce the incidence of IIE is scarce. We present the results of a retrospective chart review evaluating the incidence of IIE in adult patients who received ifosfamide to treat sarcoma at the University of Washington within a 2-year period. Patients who received methylene blue, thiamine, and/or albumin were compared to patients who did not receive these prophylactic agents concurrently with ifosfamide. The primary objective was to evaluate if prophylaxis is associated with a reduced incidence of IIE. Identifying risk factors associated with IIE was a secondary objective. The cost of using prophylaxis with ifosfamide administration was reviewed. RESULTS: A total of 166 cycles were included. For the primary endpoint, more cycles in the prophylaxis group had patients with symptoms of IIE (21.1% in the prophylaxis group vs. 8.4% in the nonprophylaxis group); p =0.026. The average number of risk factors per cycle was the same in each group; however, the type of risk factors differed. CONCLUSIONS: Prophylaxis was not associated with a reduced incidence of IIE, and it does not appear to delay time to onset of symptoms at our institution. RESULT: of this study provide no support for using methylene blue, thiamine, and/or albumin as routine prophylaxis when administering ifosfamide to adults with sarcoma.

Pharmacokinetic and clinical outcomes when ideal body weight is used to dose busulfan in obese hematopoietic stem cell transplant recipients.

Weight-based dosing of intravenous busulfan is widely used in hematopoietic cell transplantation. However, a variety of dosing weights have been described. The objective of this retrospective study was to determine the pharmacokinetic impact of using ideal body weight as the initial dosing weight in obese as compared to non-obese transplant recipients. The secondary objectives were to describe the use of alternative dosing weights, the impact on survival, and the rates of toxicities. The mean steady-state concentration was 779.3 ng/mL (n = 82) in the non-obese cohort and 673.7 ng/mL (n = 63) in the obese cohort (p < 0.001). A smaller proportion of concentrations were below goal in the non-obese cohort (10% vs. 41%, p < 0.001). Ideal body weight and adjusted body weights with a 25 and 40% correction factor are appropriate in non-obese patients; adjusted body weights with a 25 and 40% correction factor are appropriate in obese patients. There was no difference in overall survival (p = 0.18); there was a difference in median progression-free survival (1078 vs. 500 days, p = 0.045) in the non-obese compared to obese cohorts. The use of ideal body weight to dose busulfan resulted in lower steady-state concentrations, a larger proportion of subtherapeutic concentrations, and worse progression-free survival in obese patients.

Paroxysmal Nocturnal Hemoglobinuria in Pregnancy: A Dilemma in Treatment and Thromboprophylaxis.

Paroxysmal nocturnal hemoglobinuria (PNH) is a hematologic disorder characterized by an acquired somatic mutation in the phosphatidylinositol glycan class A gene which leads to a higher risk for increased venous and arterial thrombosis. Current treatment for PNH includes eculizumab. Pregnant patients who have PNH have higher risk for thrombosis and hemorrhage with both pregnancy and their underlying PNH. Treatment frequently poses conundrum. The safety and efficacy of eculizumab during pregnancy and breast feeding have not been extensively studied and contraception has been recommended due to potential for teratogenicity. We present a case of a patient who was safely on both eculizumab and modest prophylactic anticoagulation for 6 weeks post-partum.

Sapacitabine in the treatment of acute myeloid leukemia.

Prognosis of elderly patients with acute myeloid leukemia (AML) remains poor and new treatment approaches are urgently needed. A novel nucleoside analog sapacitabine has recently emerged as a feasible agent because of its oral administration and acceptable toxicity profile. Clinical efficacy of sapacitabine, both as a single agent and in combination, has been evaluated in elderly AML patients or AML patients unfit for standard intensive chemotherapy. Response rates varied from 15 to 45% in phase II studies. Sapacitabine was overall well-tolerated with gastrointestinal and myelosuppression-related complications were the most common side effects. Unfortunately, in a phase III study sapacitabine showed no clinical superiority as compared to low-dose cytarabine (LDAC) in patients with AML. Another large phase III study comparing the combination of sapacitabine with decitabine to decitabine alone is currently ongoing and is expected to be completed by the end of 2015 or by the first half of 2016.

Cellular microbiology and molecular ecology of Legionella-amoeba interaction.

Legionella pneumophila is an aquatic organism that interacts with amoebae and ciliated protozoa as the natural hosts, and this interaction plays a central role in bacterial ecology and infectivity. Upon transmission to humans, L. pneumophila infect and replicate within alveolar macrophages causing pneumonia. Intracellular proliferation of L. pneumophila within the two evolutionarily distant hosts is facilitated by bacterial exploitation of evolutionarily conserved host processes that are targeted by bacterial protein effectors injected into the host cell by the Dot/Icm type VIB translocation system. Although cysteine is semi-essential for humans and essential for amoeba, it is a metabolically favorable source of carbon and energy generation by L. pneumophila. To counteract host limitation of cysteine, L. pneumophila utilizes the AnkB Dot/Icm-translocated F-box effector to promote host proteasomal degradation of polyubiquitinated proteins within amoebae and human cells. Evidence indicates ankB and other Dot/Icm-translocated effector genes have been acquired through inter-kingdom horizontal gene transfer.

Methodological considerations in analyzing Twitter data.

Twitter is an online microblogging tool that disseminates more than 400 million messages per day, including vast amounts of health information. Twitter represents an important data source for the cancer prevention and control community. This paper introduces investigators in cancer research to the logistics of Twitter analysis. It explores methodological challenges in extracting and analyzing Twitter data, including characteristics and representativeness of data; data sources, access, and cost; sampling approaches; data management and cleaning; standardizing metrics; and analysis. We briefly describe the key issues and provide examples from the literature and our studies using Twitter data to understand public health issues. For investigators considering Twitter-based cancer research, we recommend assessing whether research questions can be answered appropriately using Twitter, choosing search terms carefully to optimize precision and recall, using respected vendors that can provide access to the full Twitter data stream if possible, standardizing metrics to account for growth in the Twitter population over time, considering crowdsourcing for analysis of Twitter content, and documenting and publishing all methodological decisions to further the evidence base.

All for one and one for all! Disparity between overall crew's and individual rowers' pacing strategies during rowing.

PURPOSE: This study examined individual contributions to overall pacing strategy during 2- and 5-km rowing trials in a coxless-4 boat. METHODS: A crew of 4 male rowers performed maximal-effort on-water trials over 2 and 5 km, and power output during every individual stroke was measured for each crew member. Mean overall boat and individual rower stroke power were calculated for each 25% epoch (25% of total strokes taken), and power for each individual epoch was calculated as a percentage of mean power maintained over the entire distance. The coefficient of variation was used to determine stroke-to-stroke and epoch-to-epoch variability for individual rowers and the overall boat. RESULTS: In both trials, the overall pacing strategy consisted of a high power output in the initial 25% that decreased in the middle 50% and increased again in the final 25%. However, individual rower data indicate wide variation in individual power profiles that did not always mimic the overall boat profile. CONCLUSIONS: This study demonstrates that overall boat power profiles during 2- and 5-km rowing trials are similar to velocity profiles previously reported for individual ergometry and on-water racing events. However, this overall profile is achieved despite considerable variation in individual rower profiles. Further research is warranted to determine the mechanisms through which individual contributions to overall pacing strategy are regulated and the effectiveness or otherwise of seemingly disparate individual strategies on overall performance.

Effect of ethanol on differential protein production and expression of potential virulence functions in the opportunistic pathogen Acinetobacter baumannii.

Acinetobacter baumannii persists in the medical environment and causes severe human nosocomial infections. Previous studies showed that low-level ethanol exposure increases the virulence of A. baumannii ATCC 17978. To better understand the mechanisms involved in this response, 2-D gel electrophoresis combined with mass spectrometry was used to investigate differential protein production in bacteria cultured in the presence or absence of ethanol. This approach showed that the presence of ethanol significantly induces and represses the production of 22 and 12 proteins, respectively. Although over 25% of the ethanol-induced proteins were stress-response related, the overall bacterial viability was uncompromised when cultured under these conditions. Production of proteins involved in lipid and carbohydrate anabolism was increased in the presence of ethanol, a response that correlates with increased carbohydrate biofilm content, enhanced biofilm formation on abiotic surfaces and decrease bacterial motility on semi-solid surfaces. The presence of ethanol also induced the acidification of bacterial cultures and the production of indole-3-acetic acid (IAA), a ubiquitous plant hormone that signals bacterial stress-tolerance and promotes plant-bacteria interactions. These responses could be responsible for the significantly enhanced virulence of A. baumannii ATCC 17978 cells cultured in the presence of ethanol when tested with the Galleria mellonella experimental infection model. Taken together, these observations provide new insights into the effect of ethanol in bacterial virulence. This alcohol predisposes the human host to infections by A. baumannii and could favor the survival and adaptation of this pathogen to medical settings and adverse host environments.