José Molina

The Phytoestrogen Genistein Affects Zebrafish Development through Two Different Pathways

Background Endocrine disrupting chemicals are widely distributed in the environment and derive from many different human activities or can also be natural products synthesized by plants or microorganisms. The phytoestrogen, genistein (4′, 5, 7-trihydroxy-isoflavone), is a naturally occurring compound found in soy products. Genistein has been the subject of numerous studies because of its known estrogenic activity. Methodology/Principal Findings We report that genistein exposure of zebrafish embryos induces apoptosis, mainly in the hindbrain and the anterior spinal cord. Timing experiments demonstrate that apoptosis is induced during a precise developmental window. Since adding ICI 182,780, an ER antagonist, does not rescue the genistein-induced apoptosis and since there is no synergistic effect between genistein and estradiol, we conclude that this apoptotic effect elicited by genistein is estrogen-receptors independent. However, we show in vitro, that genistein binds and activates the three zebrafish estrogen receptors ERα, ERβ-A and ERβ-B. Furthermore using transgenic ERE-Luciferase fish we show that genistein is able to activate the estrogen pathway in vivo during larval stages. Finally we show that genistein is able to induce ectopic expression of the aromatase-B gene in an ER-dependent manner in the anterior brain in pattern highly similar to the one resulting from estrogen treatment at low concentration. Conclusion/Significance Taken together these results indicate that genistein acts through at least two different pathways in zebrafish embryos: (i) it induces apoptosis in an ER-independent manner and (ii) it regulates aromatase-B expression in the brain in an ER-dependent manner. Our results thus highlight the multiplicity of possible actions of phytoestrogens, such as genistein. This suggests that the use of standardized endpoints to study the effect of a given compound, even when this compound has well known targets, may carry the risk of overlooking interesting effects of this compound.

Effect of appropriate combination therapy on mortality of patients with bloodstream infections due to carbapenemase-producing Enterobacteriaceae (INCREMENT): a retrospective cohort study

BACKGROUND The best available treatment against carbapenemase-producing Enterobacteriaceae (CPE) is unknown. The objective of this study was to investigate the effect of appropriate therapy and of appropriate combination therapy on mortality of patients with bloodstream infections (BSIs) due to CPE. METHODS In this retrospective cohort study, we included patients with clinically significant monomicrobial BSIs due to CPE from the INCREMENT cohort, recruited from 26 tertiary hospitals in ten countries. Exclusion criteria were missing key data, death sooner than 24 h after the index date, therapy with an active antibiotic for at least 2 days when blood cultures were taken, and subsequent episodes in the same patient. We compared 30 day all-cause mortality between patients receiving appropriate (including an active drug against the blood isolate and started in the first 5 days after infection) or inappropriate therapy, and for patients receiving appropriate therapy, between those receiving active monotherapy (only one active drug) or combination therapy (more than one). We used a propensity score for receiving combination therapy and a validated mortality score (INCREMENT-CPE mortality score) to control for confounders in Cox regression analyses. We stratified analyses of combination therapy according to INCREMENT-CPE mortality score (0-7 [low mortality score] vs 8-15 [high mortality score]). INCREMENT is registered with ClinicalTrials.gov, number NCT01764490. FINDINGS Between Jan 1, 2004, and Dec 31, 2013, 480 patients with BSIs due to CPE were enrolled in the INCREMENT cohort, of whom we included 437 (91%) in this study. 343 (78%) patients received appropriate therapy compared with 94 (22%) who received inappropriate therapy. The most frequent organism was Klebsiella pneumoniae (375 [86%] of 437; 291 [85%] of 343 patients receiving appropriate therapy vs 84 [89%] of 94 receiving inappropriate therapy) and the most frequent carbapenemase was K pneumoniae carbapenemase (329 [75%]; 253 [74%] vs 76 [81%]). Appropriate therapy was associated with lower mortality than was inappropriate therapy (132 [38·5%] of 343 patients died vs 57 [60·6%] of 94; absolute difference 22·1% [95% CI 11·0-33·3]; adjusted hazard ratio [HR] 0·45 [95% CI 0·33-0·62]; p<0·0001). Among those receiving appropriate therapy, 135 (39%) received combination therapy and 208 (61%) received monotherapy. Overall mortality was not different between those receiving combination therapy or monotherapy (47 [35%] of 135 vs 85 [41%] of 208; adjusted HR 1·63 [95% CI 0·67-3·91]; p=0·28). However, combination therapy was associated with lower mortality than was monotherapy in the high-mortality-score stratum (30 [48%] of 63 vs 64 [62%] of 103; adjusted HR 0·56 [0·34-0·91]; p=0·02), but not in the low-mortality-score stratum (17 [24%] of 72 vs 21 [20%] of 105; adjusted odds ratio 1·21 [0·56-2·56]; p=0·62). INTERPRETATION Appropriate therapy was associated with a protective effect on mortality among patients with BSIs due to CPE. Combination therapy was associated with improved survival only in patients with a high mortality score. Patients with BSIs due to CPE should receive active therapy as soon as they are diagnosed, and monotherapy should be considered for those in the low-mortality-score stratum. FUNDING Spanish Network for Research in Infectious Diseases, European Development Regional Fund, Instituto de Salud Carlos III, and Innovative Medicines Initiative.

A Multinational, Preregistered Cohort Study of β-Lactam/β-Lactamase Inhibitor Combinations for Treatment of Bloodstream Infections Due to Extended-Spectrum-β-Lactamase-Producing Enterobacteriaceae

ABSTRACT The spread of extended-spectrum-β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) is leading to increased carbapenem consumption. Alternatives to carbapenems need to be investigated. We investigated whether β-lactam/β-lactamase inhibitor (BLBLI) combinations are as effective as carbapenems in the treatment of bloodstream infections (BSI) due to ESBL-E. A multinational, retrospective cohort study was performed. Patients with monomicrobial BSI due to ESBL-E were studied; specific criteria were applied for inclusion of patients in the empirical-therapy (ET) cohort (ETC; 365 patients), targeted-therapy (TT) cohort (TTC; 601 patients), and global cohort (GC; 627 patients). The main outcome variables were cure/improvement rate at day 14 and all-cause 30-day mortality. Multivariate analysis, propensity scores (PS), and sensitivity analyses were used to control for confounding. The cure/improvement rates with BLBLIs and carbapenems were 80.0% and 78.9% in the ETC and 90.2% and 85.5% in the TTC, respectively. The 30-day mortality rates were 17.6% and 20% in the ETC and 9.8% and 13.9% in the TTC, respectively. The adjusted odds ratio (OR) (95% confidence interval [CI]) values for cure/improvement rate with ET with BLBLIs were 1.37 (0.69 to 2.76); for TT, they were 1.61 (0.58 to 4.86). Regarding 30-day mortality, the adjusted OR (95% CI) values were 0.55 (0.25 to 1.18) for ET and 0.59 (0.19 to 1.71) for TT. The results were consistent in all subgroups studied, in a stratified analysis according to quartiles of PS, in PS-matched cases, and in the GC. BLBLIs, if active in vitro, appear to be as effective as carbapenems for ET and TT of BSI due to ESLB-E regardless of the source and specific species. These data may help to avoid the overuse of carbapenems. (This study has been registered at ClinicalTrials.gov under registration no. NCT01764490.)

Emergence of resistance to daptomycin in a cohort of patients with methicillin-resistant Staphylococcus aureus persistent bacteraemia treated with daptomycin

4 Theoretically estimated AUC 24 /MIC ratios against VRE susceptible to linezolid, according to the EUCAST clinical breakpoint (MIC¼ 4 mg/L), 1 were in the recommended range for the effective treatment of severe infections with linezolid (AUC 24 /MIC ratio of 80 –120) 6 in both cases (.93.76 and .250.96, respectively). In addition , biliary trough levels (C min) of linezolid were above the EUCAST clinical breakpoint against VRE in both cases (7.42 and 37.53 mg/L, respectively), this ensuring a theoretical T .MIC of .100%. The wide interindividual pharmacokinetic variability of linezolid observed between the two patients (patient 1: V ss 31. 5 L, CL 4.2 L/h and t 1/2 5.2 h; patient 2: V ss 67.1 L, CL 1.6 L/h and t 1/2 29.1 h) confirmed previous observations in critically ill patients during treatment with linezolid. 8 This variability is expected to potentially impact more on tolerability than on efficacy. Notably, patient 2 experienced hyperlactacidaemia (an increase in lactate level of 6.2 mmol/L during linezolid treatment), which could have been related to drug overexposure potentially favoured by drug –drug interactions and renal impairment. 8 However, it should not be overlooked that linezolid has generally been shown to be safe and effective in LTx patients. 9 The therapeutic drug monitoring of plasma C min may represent a valuable tool for the optimal management of linezolid in these cases, 8 and has recently been shown to improve safety outcomes in long-term treatment. 10 We recognize that the absence of real biliary pharmacokinetic/ pharmacodynamic data may be a limitation. However, these data confirm the potentially valuable role of linezolid in the treatment of cholangitis due to multidrug-resistant Enterococcus in LTx patients, since they meet the recommendations of good biliary penetration that are given in the Tokyo guidelines. References 1 Asín E, Isla A, Canut A et al. Comparison of antimicrobial pharmacokinetic/pharmacodynamic breakpoints with EUCAST and CLSI clinical breakpoints for Gram-positive bacteria. 4 Cremaschi E, Maggiore U, Maccari C et al. Linezolid levels in a patient with biliary tract sepsis, severe hepatic failure and acute kidney injury on sustained low-efficiency dialysis (SLED). 5 Pea F, Viale P, Lugano M et al. Biliary penetration and pharmacodynamic exposure of linezolid in liver transplant patients. 6 Rayner CR, Forrest A, Meagher AK et al. Clinical pharmacodynamics of linezolid in seriously ill patients treated in a compassionate use programme. 7 Pea F, Viale P, Lugano M et …

New information about the polymyxin/colistin class of antibiotics

Infections by multidrug resistant Gram-negative bacilli (MDR-GNB) have become a major threat for patients hospitalized in intensive care units, representing a prevalent cause of morbimortality in the critically ill, since these microorganisms have developed resistance to most available antimicrobial agents. In this respect, very few therapeutic innovations have been developed in recent years, and it is not foreseen that any new drugs will be commercialized in the near future. Tigecycline represents an effective alternative in this setting, but lacks activity against Pseudomonas aeruginosa, and its use has not been validated for all organ-specific infections. Frequently, only old antibiotics like colistin remain a valid option. New pharmaceutical formulations and dosage regimens of polymyxins have considerably reduced the toxicity previously attributed to these antimicrobials, and have made it possible to reintroduce them into clinical practice. Nonetheless, the effectiveness of polymyxins is still suboptimal, and the expansion of heteroresistance and pan-drug-resistant strains of gram-negative bacilli is of concern. Improvements in dosing, alternative methods of administration and different synergic antimicrobial combinations have been proposed in recent literature, among other measures, to enhance the effectiveness of polymyxins. The latest data regarding polymyxins and their clinical use are discussed in this review.

Optimizing the Clinical Use of Vancomycin

ABSTRACT The increasing number of infections produced by beta-lactam–resistant Gram-positive bacteria and the morbidity secondary to these infections make it necessary to optimize the use of vancomycin. In 2009, the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Disease Pharmacists published specific guidelines about vancomycin dosage and monitoring. However, these guidelines have not been updated in the past 6 years. This review analyzes the new available information about vancomycin published in recent years regarding pharmacokinetics and pharmacodynamics, serum concentration monitoring, and optimal vancomycin dosing in special situations (obese people, burn patients, renal replacement therapy, among others). Vancomycin efficacy is linked to a correct dosage which should aim to reach an area under the curve (AUC)/MIC ratio of ≥400; serum trough levels of 15 to 20 mg/liter are considered a surrogate marker of an AUC/MIC ratio of ≥400 for a MIC of ≤1 mg/liter. For Staphylococcus aureus strains presenting with a MIC >1 mg/liter, an alternative agent should be considered. Vancomycin doses must be adjusted according to body weight and the plasma trough levels of the drug. Nephrotoxicity has been associated with target vancomycin trough levels above 15 mg/liter. Continuous infusion is an option, especially for patients at high risk of renal impairment or unstable vancomycin clearance. In such cases, vancomycin plasma steady-state level and creatinine monitoring are strongly indicated.

Diagnosis and antimicrobial treatment of invasive infections due to multidrug-resistant Enterobacteriaceae. Guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology

The spread of multidrug-resistant Enterobacteriaceae related to the production of extended-spectrum β-lactamases and carbapenemases is a serious public health problem worldwide. Microbiological diagnosis and therapy of these infections are challenging and controversial. Clinically relevant questions were selected and the literature was reviewed for each of them. The information from the selected articles was extracted and recommendations were provided and graded according to the strength of the recommendations and quality of the evidence. The document was opened to comments from the members from the Spanish Society of Infectious Diseases and Clinical Microbiology, which were considered for inclusion in the final version. Evidence-based recommendations are provided for the use of microbiological techniques for the detection of extended-spectrum β-lactamases and carbapenemases in Enterobacteriaceae, and for antibiotic therapy for invasive/severe infections caused by these organisms. The absence of randomised controlled trials is noteworthy; thus, recommendations are mainly based on observational studies (that have important methodological limitations), pharmacokinetic and pharmacodynamics models, and data from animal studies. Additionally, areas for future research were identified.

Clinical Features of Infections and Colonization by Acinetobacter Genospecies 3

ABSTRACT Two hundred twenty-one isolates of Acinetobacter baumannii and 15 of Acinetobacter genospecies 3 (AG3) were consecutively collected in a 30-day period during the nationwide project GEIH-Ab2000. Nosocomial acquisition (P = 0.01), intensive care unit admission (P = 0.02), and antibiotic pressure (P = 0.03) were observed to be lower in the AG3 group. AG3 isolates were more frequently implied in wound infections (P = 0.05), while A. baumannii tended to be recovered from respiratory samples (P = 0.08). To our knowledge, this is the first report analyzing the clinical differences among Acinetobacter genospecies, with our findings suggesting that clinical features of AG3 may not be equivalent to those traditionally described for A. baumannii.

Executive summary of the diagnosis and antimicrobial treatment of invasive infections due to multidrug-resistant Enterobacteriaceae. Guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC)

The spread of multidrug-resistant Enterobacteriaceae related to the production of extended-spectrum β-lactamases (ESBL) and carbapenemases is a serious public health problem worldwide. Microbiological diagnosis and therapy of these infections are challenging and controversial. After the selection of clinically relevant questions, this document provides evidence-based recommendations for the use of microbiological techniques for the detection of ESBL- and carbapenemase-producing Enterobacteriaceae, and for antibiotic therapy for invasive infections caused by these organisms. The absence of randomized-controlled trials is noteworthy, thus recommendations are mainly based on observational studies, that have important methodological limitations, pharmacokinetic and pharmacodynamics models, and data from animal studies. Additionally, areas for future research were identified.

Aminoglucósidos y polimixinas

The emergence of multidrug-resistant strains of gram-negative bacilli during the last decade has generated renewed interest in older antimicrobials that had been relegated to a second line because of a poorer safety profile, but that are still active against these microorganisms. Once-daily administration of aminoglycosides has limited the toxicity of these agents and enabled their reintroduction into clinical practice. Recent studies have shown no additional benefits of concomitant administration of aminoglycosides with current ss-lactams, and the available evidence does not support the use of once-daily administration for all indications. The new formulations and dosages of polymyxins have also reduced the toxicity rates attributed to these agents in the past. Although more extensive studies are required to properly define their pharmacokinetics and effectiveness, the available data have shown favorable outcomes for patients with infection due to multiresistant gram-negative bacilli treated with colistin, either alone or combined with other antimicrobial agents.