Performance of Four Fosfomycin Susceptibility Testing Methods against an International Collection of Clinical Pseudomonas aeruginosa Isolates.

Fosfomycin has been shown to have a wide spectrum of activity against multidrug-resistant Gram-negative bacteria; however, breakpoints have been established only for Escherichia coli or Enterobacterales per the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility Testing (EUCAST), respectively. A lack of additional organism breakpoints limits clinical use of this agent and has prompted extrapolation of these interpretive categories to other organisms like Pseudomonas aeruginosa without supporting evidence. Further complicating the utility of fosfomycin is the specified method for MIC determination, namely, agar dilution, which is not widely available and is both labor and time intensive. We therefore sought to determine the susceptibility of a large international collection of P. aeruginosa isolates (n = 198) to fosfomycin and to compare testing agreement rates across four methods: agar dilution, broth microdilution, disk diffusion, and Etest. Results were interpreted according to CLSI E. coli breakpoints, with 49.0 to 85.8% considered susceptible, dependent upon the testing method used. Epidemiological cutoff values were calculated and determined to be 256 µg/ml and 512 µg/ml for agar dilution and broth microdilution, respectively. Agreement rates were analyzed using both agar dilution and broth microdilution with a resulting high essential agreement rate of 91.3% between the two susceptibility testing methods. These results indicate that broth microdilution may be a reliable method for fosfomycin susceptibility testing against P. aeruginosa and stress the need for P. aeruginosa-specific breakpoints.

Bitter taste sensitivity, food intake, and risk of malignant cancer in the UK Women's Cohort Study.

PURPOSE: There is variability in sensitivity to bitter tastes. Taste 2 Receptor (TAS2R)38 binds to bitter tastants including phenylthiocarbamide (PTC). Many foods with putative cancer preventive activity have bitter tastes. We examined the relationship between PTC sensitivity or TAS2R38 diplotype, food intake, and cancer risk in the UK Women's Cohort Study. METHODS: PTC taste phenotype (n = 5500) and TAS238 diplotype (n = 750) were determined in a subset of the cohort. Food intake was determined using a 217-item food-frequency questionnaire. Cancer incidence was obtained from the National Health Service Central Register. Hazard ratios (HR) were estimated using multivariable Cox proportional hazard models. RESULTS: PTC tasters [HR 1.30, 95% confidence interval (CI) 1.04, 1.62], but not supertasters (HR 0.98, CI 0.76, 1.44), had increased cancer risk compared to nontasters. An interaction was found between phenotype and age for supertasters (p = 0.019) but not tasters (p = 0.54). Among women > 60 years, tasters (HR 1.40, CI 1.03, 1.90) and supertasters (HR 1.58, CI 1.06, 2.36) had increased cancer risk compared to nontasters, but no such association was observed among women ≤ 60 years (tasters HR 1.16, CI 0.84, 1.62; supertasters HR 0.54, CI 0.31, 0.94). We found no association between TAS2R38 diplotype and cancer risk. We observed no major differences in bitter fruit and vegetable intake. CONCLUSION: These results suggest that the relationship between PTC taster phenotype and cancer risk may be mediated by factors other than fruit and vegetable intake.

Nutritional risk factors predict severe acute graft-versus-host disease and early mortality in pediatric allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Malnutrition is a pro-inflammatory state, yet data on nutritional risk factors and development of acute graft-versus-host disease (aGVHD) are extremely limited. PROCEDURE: We conducted a retrospective cohort analysis of pediatric patients up to age 21 years who underwent allogeneic hematopoietic stem cell transplantation (HSCT) at the Children's Hospital of Philadelphia from January 2011 to September 2014 to determine whether malnutrition was associated with development of aGVHD and early mortality. We identified body mass index (BMI) percentile and serum albumin levels as potential markers of malnutrition and defined two composite nutritional risk variables as any of the following: albumin < 2.8 g/dl, weight loss ≥10% from baseline, and low BMI [<25th (NUT25) or <5th percentile (NUT5)]. Nutritional markers and GVHD grade were assessed at baseline, 30, 60, and 90 days post-HSCT, and patients were censored upon development of GVHD. RESULTS: BMI <25th or <5th percentile, NUT25, and NUT5 at the beginning of any 30-day period predicted a three- to fourfold risk of developing of severe (grade III-IV) aGVHD in the subsequent 30 days in models adjusted for age, sex, donor source, and degree of human leukocyte antigen matching. Mortality at day 100 was low, but NUT25 risk at baseline conferred an increased risk of death (7.9% vs. 1%, P = 0.035). CONCLUSIONS: Malnutrition is a targetable risk factor in pediatric HSCT; prospective trials are needed to investigate this relationship further and identify effective nutritional interventions.

Fractures in a nationwide population-based cohort of users of breast cancer hormonal therapy.

PURPOSE: Although users of aromatase inhibitors have higher total fracture risk in some randomized trials, little is known about their risk outside of clinical trials or in older higher-risk cohorts. METHODS: In a population-based retrospective cohort study, we identified all older US Medicare D prescription drug insurance plan-enrolled women who had initial breast cancer surgery in 2006-2008 and began hormonal therapy (an aromatase inhibitor (AI) or tamoxifen) within the subsequent year. Total nonvertebral and hip fractures through 2012 were identified using a validated algorithm. The association of fracture outcomes with hormonal therapy type was assessed using competing risk regression models that accounted for differences in measured baseline covariates. Treatment assignment bias was reduced using inverse probability of treatment weighting computed from propensity scores. RESULTS: Among 23,378 women taking hormonal therapy (23.2% aged 80 or over), there were 3000 total and 436 hip fractures. Although AI users were younger and had lower comorbidity, after propensity score weighting, these and other covariates were balanced. Total nonvertebral risk was higher for users of AIs compared with tamoxifen, HR 1.11 (1.02-1.21), but the small increase in risk for hip fracture was not statistically significant, HR 1.04 (0.84-1.30). CONCLUSIONS: Although total nonvertebral fracture risk was higher among AI users, differences in hip fractures were not significant in a large population-based cohort of older women. IMPLICATIONS FOR CANCER SURVIVORS: Use of aromatase inhibitors by older women is associated with high risk for nonvertebral fracture that is increased compared with use of tamoxifen. Fracture risk should be assessed among patients taking these medications.

Medicare D Subsidies and Racial Disparities in Persistence and Adherence With Hormonal Therapy.

Purpose To investigate the role of out-of-pocket cost supports through the Medicare Part D Low-Income Subsidy on disparities in breast cancer hormonal therapy persistence and adherence by race or ethnicity. Methods A nationwide cohort of women age ≥ 65 years with a breast cancer operation between 2006 and 2007 and at least one prescription filled for oral breast cancer hormonal therapy was identified from all Medicare D enrollees. The association of race or ethnicity with nonpersistence (90 consecutive days with no claims for a hormonal therapy prescription) and nonadherence (medication possession rate < 80%) was examined. Survival analyses were used to account for potential differences in age, comorbidity, or intensity of other treatments. Results Among the 25,111 women in the study sample, 77% of the Hispanic and 70% of the black women received a subsidy compared with 21% of the white women. By 2 years, 69% of black and 70% of Hispanic patients were persistent compared with 61% of white patients. In adjusted analyses, patients in all three unsubsidized race or ethnicity groups had greater discontinuation than subsidized groups (white patients: hazard ratio [HR], 1.83; 95% CI, 1.70 to 1.95; black patients: HR, 2.09; 95% CI, 1.73 to 2.51; Hispanic patients: HR, 3.00; 95% CI, 2.37 to 3.89). Racial or ethnic persistence disparities that were present for unsubsidized patients were not present or reversed among subsidized patients. All three subsidized race or ethnicity groups also had higher adherence than all three unsubsidized groups, although with the smallest difference occurring in black women. Conclusion Receipt of a prescription subsidy was associated with substantially improved persistence to breast cancer hormonal therapy among white, black, and Hispanic women and lack of racial or ethnic disparities in persistence. Given high subsidy enrollment among black and Hispanic women, policies targeted at low-income patients have the potential to also substantially reduce racial and ethnic disparities.

Bone Mineral Density Testing Disparities Among Patients With Breast Cancer Prescribed Aromatase Inhibitors.

OBJECTIVES: Aromatase inhibitors (AIs) are standard adjuvant therapy for postmenopausal women with early-stage, estrogen receptor-positive breast cancer. We designed our study to determine whether women initiating adjuvant therapy with an AI underwent baseline bone mineral density testing, as well as what factors predicted adherence with testing guidelines. METHODS: Medicare Parts A, B, and D claims were used to identify a cohort of women aged 67 years and older with incident breast cancer in 2006 and 2007 who started AI therapy. Medicare claims provided information about bone density testing, as well as demographic and other treatment data through 2012. We also ascertained which patients were treated with bisphosphonates and studied the relationship of bisphosphonate therapy with bone density testing. RESULTS: Approximately two-thirds of patients had baseline bone density testing. Older age, comorbidity, low income, and black race were associated with lower rates of baseline bone density testing. Testing rates decreased substantially with increasing age from 73% for women aged 67 to 70 years to 51% for those 85 years of age and older (adjusted odds ratio for not being tested, 2.48 [Cl, 2.17-2.82]). The proportion of women who had neither bone density testing nor bisphosphonate therapy increased with age as well. CONCLUSIONS: Despite the importance of age as a risk factor for fractures, older women starting treatment with AIs for treatment of breast cancer are less likely to undergo recommended bone density assessment.

The introduction of generic aromatase inhibitors and treatment adherence among Medicare D enrollees.

BACKGROUND: Aromatase inhibitors (AIs) substantially reduce breast cancer mortality in clinical trials, but high rates of nonadherence to these long-term oral therapies have reduced their impact outside of trials. We examined the association of generic AI availability with AI adherence among a large national breast cancer cohort. METHODS: Using a quasi-experimental prepost design, we examined the effect of generic AI introductions (7/2010 and 4/2011) on adherence among a national cohort of women with incident breast cancer in 2006 and 2007 who were enrolled in the Medicare D pharmaceutical coverage program. Medicare D claims were used to calculate AI adherence, defined as a medication possession ratio of 80% or more of eligible days, over 36 months. Multivariable logistic regression models estimated with generalized estimating equations were applied to longitudinal adherence data to control for possible confounders, including receipt of a Medicare D low-income subsidy, and to account for repeated measures. All statistical tests were two-sided. RESULTS: Sixteen thousand four hundred sixty-two Medicare D enrollees were eligible. Adherence declined throughout the study. However, among women without a subsidy, the median quarterly out-of-pocket cost of anastrozole fell from $183 in the fourth quarter of 2009 to $15 in 2011, and declines in adherence were attenuated with generic AI introductions. Regression-adjusted adherence probabilities were estimated to be 5.4% higher after generic anastrozole was introduced in 2010 and 11% higher after generic letrozole/exemestane was introduced in 2011. Subsidy recipients had higher adherence rates throughout the study. CONCLUSIONS: The introduction of generic medications attenuated the decline in adherence to AIs over three years of treatment among breast cancer survivors not receiving low-income subsidies for Medicare D coverage.

Combining systemic retinoids with biologic agents for moderate to severe psoriasis.

BACKGROUND: Moderate to severe psoriasis, which is defined as psoriasis affecting more than 20% of the body surface area, often requires a combination of therapies to achieve remission. Although numerous data exist regarding the use of acitretin and biologic agent therapy alone for psoriasis, little is known about the efficacy, safety, and tolerability of acitretin combined with biologic agents. METHODS: Fifteen patients with psoriasis treated with concomitant acitretin and a biologic agent were identified, and their charts were reviewed for response to therapy, additional therapy necessary for disease management, side-effects, and laboratory abnormalities whilst on combination therapy. The Institutional Review Board did not require approval for this chart review. RESULTS: Twenty-nine per cent of patients showed clearance of psoriasis, 43% of patients showed an improvement of 90%, 14% showed an improvement of 75%, and 7.1% showed no change. During treatment with acitretin and biologic agent, five patients required no adjunctive treatment. Three patients were able to stop narrow-band ultraviolet-B (UV-B) therapy after an average of 2.33 months of combination therapy. Only one patient continued to require phototherapy (UV-B) in addition to the biologic agent. Three patients developed squamous cell carcinoma (SCC) whilst on combination therapy, but all patients had a previous history of SCC. One patient developed non-Hodgkin's lymphoma after 3 years of etanercept and acitretin, and the etanercept was discontinued. CONCLUSIONS: Acitretin combined with biologic agents offers a promising method of managing refractory psoriasis. More research is needed to determine the long-term safety and efficacy of this combination.

The mutagenicity of urban particulate matter in an enzyme free system is associated with the generation of reactive oxygen species.

Urban particulate matter (UPM) contributes to lung cancer incidence. UPM has been shown to be genotoxic to mammalian cells and to induce mutations in the Ames assay. Here, we have studied the induction of mutations generated by direct acting mutagenic components of UPM, using the supF forward mutation assay. Plasmid pSP189 was exposed to UPM in aqueous solution in the presence of sucrose buffer, to reduce strand breaks. The mutation frequency induced by 1 microg/microl UPM was 4.99 mutants per 10(4) colonies. This was reduced to 0.84 and 1.48 mutants per 10(4) colonies by addition of mannitol (1 mM) or EDTA (1 mM), respectively. A large percentage of mutant plasmids contained frameshift mutations (57%), and 31% of mutant plasmids contained multiple mutations. Of the base substitution mutations, 88% were at GC pairs, with twice as many transversions as transitions. The types of mutations induced, the reduction of mutagenicity by the inclusion of the free radical scavenger, mannitol, or the metal chelator, EDTA, and the sequence context of the induced mutations all support the conclusion that the majority of mutations were induced by reactive oxygen species generated by metal ions present in the UPM. Most mutation studies with UPM have focused on organic carcinogens present on UPM. Our results highlight the potential contribution of metal ions to the mutagenicity of UPM.

Benzo[a]pyrene and its metabolites combined with ultraviolet A synergistically induce 8-hydroxy-2'-deoxyguanosine via reactive oxygen species.

We previously reported that benzo[a]pyrene (BaP) and UVA radiation synergistically induced oxidative DNA damage via 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation in vitro. The present study shows that microsomal BaP metabolites and UVA radiation potently enhance 8-OHdG formation in calf thymus DNA about 3-fold over the parent compound BaP. Utilization of various reactive oxygen species scavengers revealed that singlet oxygen and superoxide radical anion were involved in the 8-OHdG formation induced by microsomal BaP metabolites and UVA. Two specific BaP metabolites, benzo[a]pyrene-r-7,t-8-dihydrodiol-t-9,10-epoxide (+/-) (anti) (BPDE) and BaP-7,8-dione, were further tested for synergism with UVA. BaP-7,8-dione showed an effect on 8-OHdG formation induced by UVA radiation that was similar to that of the parent BaP, whereas BPDE exhibited significantly higher induction of 8-OHdG than BaP. At as low as 0.5 microM, BPDE plus UVA radiation substantially increased 8-OHdG levels about 25-fold over the parent BaP. BPDE increased the formation of 8-OHdG levels in both BPDE concentration- and UVA dose-dependent manners. Additionally, singlet oxygen was found to play a major role in 8-OHdG induction by BPDE and UVA. These results suggest that BaP metabolites such as BPDE synergize with UVA radiation to produce ROS, which in turn induce DNA damage.

Parasite-specific immunoglobulin isotypes during lethal and non-lethal murine malaria infections.

Production of parasite-specific antibodies is an important component of immunity to blood stage malaria infection, as shown by several previous studies in rodent models. However, no study has addressed the induction of humoral immunity by different parasites in a genetically homogeneous host population. Here, levels of parasite-specific immunoglobulin isotypes were measured during primary infections of Plasmodium chabaudi and of Plasmodium yoelii in inbred NIH mice inoculated with cloned lines of either avirulent or virulent erythrocytic parasites. Non-lethal infections were characterized by early and late significant upregulation of IgG2a and IgG1, respectively. In contrast, for lethal infections, a slower, reduced IgG2a response correlated with a rapidly fatal outcome prior to any significant synthesis of IgG1. It is proposed that the sequential upregulated synthesis of parasite-specific IgG2a (cytophilic) and IgG1 (non-cytophilic) is associated with protective immunity to blood stage malaria infections in mice. This may provide an immunological framework for examining humoral immunity to malaria in humans.

Intraspecific variation in photosynthetic responses of trebouxioid lichens with reference to the activity of a carbon-concentrating mechanism.

The photosynthetic responses of a range of trebouxioid lichens were investigated to determine whether variations in net assimilation rates shown by populations of the same species collected from different habitats could be correlated with adjustments in carbon-concentrating mechanism (CCM) activity. The activity of a CCM was inferred from the high affinity for CO2 [i.e. low CO2 compensation point (Γ); low external CO2 concentration at which half-maximal assimilation rates are reached (K 0.5 CO2)], the release of a pool of accumulated dissolved inorganic carbon (Ci) during light/dark transient measurements of CO2 exchange and values for carbon isotope discrimination intermediate between those characteristic of C3 and C4 terrestrial plants. Higher net and gross assimilation rates were expressed by lichens collected from shaded woodland habitats. The higher rates were not accounted for by variations in chlorophyll content. Lichens with high assimilation rates also showed an increased affinity for CO2 as demonstrated by low CO2 compensation points and K 0.5 values and the magnitude of the Ci pool accumulated upon illumination and released after darkening of the thalli. However, there was no correlation between assimilation rates and organic matter or instantaneous carbon isotope discrimination measurements, with the latter remaining roughly consistent whatever the provenance or species of the lichen material. The data are discussed with reference to significant environmental factors which are likely to control photosynthesis in the habitats studied.

Potential effects of rising tropospheric concentrations of CO2 and O3 on green-algal lichens.

Pormelia sulcata Taylor was used as a model to examine the effects of elevated CO2 and/or O3 on green algal lichens. Thalli were exposed for 30 d in duplicate controlled-environment chambers to two atmospheric concentrations of CO2 ('ambient' [350µmol mol-1 ] and 'elevated' [700µmol mol-1 ] 24 h d-1 ) and two O3 regimes ('non-polluted' air [CF, < 5 nmol mol-1 ] and 'polluted' air [15 nmol mol-1 overnight rising to a midday maximum of 75 nmol mol-1 ]), in a factorial design. Elevated CO2 , or elevated O3 depressed the light saturated rate of CO2 , assimilation Asat ) measured at ambient CO2 , by 30% and 18%, respectively. However, despite this effect ultrastructure) studies revealed increased lipid storage in cells of the photobiont in response to CO2 -enrichment. Simultaneous exposure to elevated O3 reduced CO2 -induced lipid accumulation and reduced Asat in an additive manner. Gold-antibody labelling revealed that the decline in photosynthetic capacity induced by elevated CO2 and/or O3 was accompanied by a parallel decrease in the concentration of Rubiscoa in the algal pyrenoid (r= 0.93). Interestingly, differences in the amount of Rubisco protein were not correlated with changes in pyrenoid volume. Measurements of in vivo chlorophyll-fluorescence induction kinetics showed that the decline in Asat induced by elevated CO2 , and/or O2 , was not associated with significant changes in the photochemical efficiency of photosystem (PS) II. Although the experimental conditions inevitably imposed some stress on the thalli, revealed as a significant decline in the efficiency of PS II photochemistry, and enhanced starch accumulation in the photobiont over the fornication period, the study shows that the green-algal lichen symbiosis might be influenced by future changes in atmospheric composition. Photosynthetic capacity, measured at ambient CO2 , was found to be reduced after a controlled 30 d exposure to elevated CO2 , and/or O3 and this effect was associated with a parallel decline in the amount of Rubisco in the pyrenoid of algal chloroplasts.