Impact of Antimicrobial Stewardship Intervention on Coagulase-Negative Staphylococcus Blood Cultures in Conjunction with Rapid Diagnostic Testing

Rapid diagnostic testing with matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) decreases the time to organism identification by 24 to 36 h compared to the amount of time required by conventional methods. However, there are limited data evaluating the impact of MALDI-TOF with real-time antimicrobial stewardship team (AST) review and intervention on antimicrobial prescribing and outcomes for patients with bacteremia and blood cultures contaminated with coagulase-negative Staphylococcus (CoNS). A quasiexperimental study was conducted to analyze the impact of rapid diagnostic testing with MALDI-TOF plus AST review and intervention for adult hospitalized patients with blood cultures positive for CoNS. Antibiotic prescribing patterns and clinical outcomes were compared before and after implementation of MALDI-TOF with AST intervention for patients with CoNS bacteremia and CoNS contamination. A total of 324 patients with a positive CoNS blood culture were included; 246 were deemed to have contaminated cultures (117 in the preintervention group and 129 in AST the intervention group), and 78 patients had bacteremia (46 in the preintervention group and 32 in the AST intervention group). No differences in demographics were seen between the groups, and similar rates of contamination occurred between the preintervention and AST intervention groups (64.3% versus 72.6%, P = 0.173). Patients with bacteremia were initiated on optimal therapy sooner in the AST intervention group (58.7 versus 34.4 h, P = 0.030), which was associated with a similarly decreased mortality (21.7% versus 3.1%, P = 0.023). Patients with CoNS-contaminated cultures had similar rates of mortality, lengths of hospitalization, recurrent bloodstream infections, and 30-day hospital readmissions, but the AST intervention group had a decreased duration of unnecessary antibiotic therapy (1.31 versus 3.89 days, P = 0.032) and a decreased number of vancomycin trough assays performed (0.88 versus 1.95, P < 0.001). In patients with CoNS bacteremia, rapid pathogen identification integrated with real-time stewardship interventions improved timely organism identification and initiation of antibiotic therapy. Patients in the AST group with blood cultures contaminated with CoNS had decreased inappropriate antimicrobial prescribing and decreased unnecessary serum vancomycin trough assays.     

Mechanisms that regulate localization of a DNA double-strand break to the nuclear periphery

DNA double-strand breaks (DSBs) are among the most deleterious forms of DNA lesions in cells. Here we induced site-specific DSBs in yeast cells and monitored chromatin dynamics surrounding the DSB using Chromosome Conformation Capture (3C). We find that formation of a DSB within G1 cells is not sufficient to alter chromosome dynamics. However, DSBs formed within an asynchronous cell population result in large decreases in both intra- and interchromosomal interactions. Using live cell microscopy, we find that changes in chromosome dynamics correlate with relocalization of the DSB to the nuclear periphery. Sequestration to the periphery requires the nuclear envelope protein, Mps3p, and Mps3p-dependent tethering delays recombinational repair of a DSB and enhances gross chromosomal rearrangements. Furthermore, we show that components of the telomerase machinery are recruited to a DSB and that telomerase recruitment is required for its peripheral localization. Based on these findings, we propose that sequestration of unrepaired or slowly repaired DSBs to the nuclear periphery reflects a competition between alternative repair pathways.     

Detection of heat-stable antigens of Campylobacter jejuni and C. coli by direct agglutination and passive hemagglutination

The two serotyping schemes for the detection of heat-stable antigens of Campylobacter jejuni and Campylobacter coli use the same strains for antiserum production but differ in the detection systems used for identifying agglutination. The Penner method uses passive hemagglutination (PHA) while the Laboratory of Enteric Pathogens method uses the same antisera but in a whole-bacterial-cell direct agglutination (DA) protocol. C. jejuni produces a polysaccharide capsule, which is antigenic, and is the main component detected by the PHA method. The DA method will detect both capsule antigens and lipopolysaccharide (LPS) or lipooligosaccharide (LOS) surface antigens. Comparison of both methods by using a selection of isolates from human infection has shown a range of variation in agglutination specificity, reflecting the differences in antigens detected by the two methods. While 27.4% of the 416 C. jejuni isolates reacted with the antisera raised against the same type strains by either method, the majority showed a range of more complex relationships. None of the 37 C. coli isolates reacted with the same antiserum by both methods. Together the two schemes gave a total of 102 distinct combined serogroups for C. jejuni and 16 for C. coli. Thus, while some clonally related isolates share the same capsule and LOS or LPS antigens, other strains appear to have a common capsule antigen but differ in their LPS or LOS structures or vice versa.     

L-ficolin binding and lectin pathway activation by acetylated low-density lipoprotein

L-ficolin, like mannan-binding lectin (MBL), is a lectin pathway activator present in normal human plasma. Upon binding ligand, l-ficolin similarly initiates C4 cleavage via the serine protease MBL-associated serine protease-2 (MASP-2). We sought further insight into l-ficolin binding reactions and MASP-2 activation by passing plasma through GlcNAc-derivatized Sepharose. l-Ficolin bound in 1.0 M NaCl-ethylenediamine tetraacetic acid (EDTA), and remained bound in NaCl-free EDTA, while MASP-2 eluted in proenzyme form ( approximately 20% yield, > 40 000-fold purification). L-Ficolin was eluted with GlcNAc in 1.0 M NaCl ( approximately 10% yield, > 3000-fold purification), with trace amounts of C3, alpha(2)-macroglobulin and both native and activated MASP-2. These preparations were utilized to investigate l-ficolin reactivities with acetylated low-density lipoprotein (A-LDL) as a model ligand in albumin-free systems. L-Ficolin bound strongly to A-LDL in the absence as well as presence of calcium, including saline-EDTA, and was optimal in 1.0 M NaCl-EDTA, but binding failed to occur in EDTA in the absence of NaCl. The addition of l-ficolin to immobilized A-LDL resulted in activation of MASP-2 in unmodified but not ficolin-depleted plasma unless l-ficolin was restored. We conclude that A-LDL is a useful ligand for investigation of l-ficolin function; both binding and activation are optimally examined in systems free of albumin; and ligand binding in 1.0 M NaCl in EDTA can be useful in the isolation of l-ficolin and native MASP-2.     

Low-frequency H-reflex depression in trained human soleus after spinal cord injury

After spinal cord injury (SCI), widespread reorganization occurs within spinal reflex systems. Regular muscle activity may influence reorganization of spinal circuitry after SCI. The purpose of this study is to investigate the effects of long-term soleus training on H-reflex depression in humans after SCI. Seven subjects with acute (<7 weeks) SCI (AC group) underwent testing of H-reflex depression at several frequencies of repetitive stimulation. Eight subjects (including 3 from AC) stimulated one soleus muscle daily, leaving the other leg as an untrained within-subject control. Trained limb H-reflexes were assessed during year 1 (TR1) and year 2 (TR2) of training. Untrained limbs were tested during year 2 (UN). H-reflex amplitude was lower at 1, 2 and 5 Hz than at 0.1 or 0.2 Hz (p < 0.05). The pattern of depression differed between AC and UN (p < 0.05), but not between TR2 and UN (p > 0.05) despite significant adaptations in torque and fatigue resistance (p < 0.05). Three subjects who began training very early after SCI retained H-reflex post activation depression, suggesting that early intervention of daily muscular activity may be important.     

Dynamic modeling in ovarian cancer: An original approach linking early changes in modeled longitudinal CA-125 kinetics and survival to help decisions in early drug development

Objective

Early prediction of the expected benefit of treatment in recurrent ovarian cancer (ROC) patients may help in drug development decisions. The actual value of 50% CA-125 decrease is being reconsidered. The main objective of the present study was to quantify the links between longitudinal assessments of CA-125 kinetics and progression-free survival (PFS) in treated recurrent ovarian cancer (ROC) patients.

Methods

The CALYPSO randomized phase III trial database comparing two platinum-based regimens in ROC patients was randomly split into a “learning dataset” and a “validation dataset”. A parametric survival model was developed to associate longitudinal modeled CA-125 changes (ΔCA125), predictive factors, and PFS. The predictive performance of the model was evaluated with simulations.

Results

The PFS of 534 ROC patients were properly characterized by a parametric mathematical model. The modeled ΔCA125 from baseline to week 6 was a better predictor of PFS than the modeled fractional change in tumor size. Simulations confirmed the model's predictive performance.

Conclusions

We present the first parametric survival model quantifying the relationship between PFS and longitudinal CA-125 kinetics in treated ROC patients. The model enabled calculation of the increase in ΔCA125 required to observe a predetermined benefit in PFS to compare therapeutic strategies in populations. Therefore, ΔCA125 may be a predictive marker of the expected gain in PFS and an early predictive tool in drug development decisions.     

A phase II trial of sunitinib in women with metastatic or recurrent endometrial carcinoma: A study of the Princess Margaret,Chicago and California Consortia

Objective

Treatment options remain limited for women with relapsed/metastatic endometrial cancer (EC). Angiogenesis is one of the major components of tumor progression and thus an attractive target. The aim of this phase II trial was to assess the efficacy and tolerability of sunitinib, an oral multitargeted receptor tyrosine-kinase inhibitor with antiangiogenic and antitumor activity in the treatment of recurrent EC.

Methods

We performed a multicenter, single arm, two-stage phase II study of sunitinib, 50 mg daily administered on a 4 weeks on–2 weeks off schedule. Eligibility criteria included recurrent/metastatic EC or carcinosarcoma with no more than one prior line of chemotherapy. The primary endpoint was objective response rate.

Results

34 women were enrolled; 33 received at least one dose of sunitinib and were included in the analyses. Six women (18.1%) had a partial response and six additional women (18.1%) stable disease. In total, ten patients (30.3%) had disease control for at least 6 months and of these, seven were controlled for more than one year. Median progression free and overall survival times were 3 months and 19.4 months, respectively. Adverse events related to treatment were frequent. At least one grade 3 toxicity occurred in 30 patients and dose reductions were required in 17 patients (52%). The most common grade 3 toxicities were fatigue, hypertension, palmar–plantar erythrodysesthesia, diarrhea and hematologic.

Conclusion

Sunitinib therapy showed promising activity in women with recurrent EC. Toxicity was seen frequently but was manageable. Anti-angiogenic agents warrant further investigation in EC to define which patients will derive the greatest benefit.