Clinical and economic outcomes of a prospective antimicrobial stewardship program.

PURPOSE: A pre-post analysis of an antimicrobial stewardship program (ASP) involving the use of data-mining software to prospectively identify cases for ASP intervention was conducted. METHODS: The investigators evaluated clinical outcomes and cost metrics before and after implementation of the ASP, which entailed daily physician review of summary reports on all adult inpatients receiving antimicrobial therapy. The primary outcome measures were annual antimicrobial expenditures and rates of infections due to common nosocomial pathogens; secondary outcome measures included patient survival and length of stay (LOS) in cases involving the indicator diagnoses of pneumonia and abdominal sepsis. RESULTS: Antimicrobial expenditures, which had increased by an average of 14.4% annually in the years preceding ASP implementation, decreased by 9.75% in the first year of the program and remained relatively stable in subsequent years, with overall cumulative cost savings estimated at $1.7 million. Rates of nosocomial infections involving Clostridium difficile, methicillin-resistant Staphylococcus aureus, and vancomycin-resistant enterococci all decreased after ASP implementation. A pre-post comparison of survival and LOS in patients with pneumonia (n = 2186) or abdominal sepsis (n = 225) showed no significant differences in those outcomes in either patient group, possibly due to the hospital's initiation of other, concurrent infection-control programs during the study period. CONCLUSION: A prospective collaborative ASP employed automated reports to efficiently identify key data for ASP review. After ASP implementation, antimicrobial expenditures and rates of nosocomial infections caused by resistant pathogens dropped without significant changes in patient survival, LOS, and readmissions for the two studied illness categories.

Ceftobiprole: A novel, broad-spectrum cephalosporin with activity against methicillin-resistant Staphylococcus aureus.

PURPOSE: The pharmacology, antimicrobial activity, pharmacokinetics, pharmacodynamics, clinical efficacy, safety, and place in therapy of ceftobiprole are reviewed. SUMMARY: Ceftobiprole, a novel, broad-spectrum, parenteral cephalosporin, inhibits the cell-wall synthesis of penicillin-binding proteins (PBPs) PBP2a and PBP2x, responsible for the resistance in staphylococci and pneumococci, respectively. Ceftobiprole has good activity against gram-positive aerobes and anaerobes, and its activity against gram-negative aerobes and anaerobes is species dependent. Ceftobiprole is relatively inactive against Acinetobacter species. Its ability to bind relevant PBPs of resistant gram-positive and gram-negative bacteria indicates its potential use in the treatment of hospital-acquired pneumonia and complicated skin and skin-structure infections (cSSSIs). Ceftobiprole is primarily excreted unchanged by the kidneys and exhibits linear pharmacokinetics. The half-life of the drug is approximately 3-4 hours. It exhibits minimal plasma protein binding (16%). Ceftobiprole does not inhibit the cytochrome P-450 isoenzyme system, so the possibility of drug-drug interactions is low. The drug has not been approved for use in the United States but has been approved in Canada and elsewhere. Ceftobiprole is currently undergoing Phase III clinical trials and has demonstrated activity against methicillin-resistant Staphylococcus aureus, penicillin-resistant Streptococcus pneumoniae, and Pseudomonas aeruginosa. Completed Phase III trials used i.v. dosages of 500 mg every 8-12 hours. The most commonly observed adverse effects of ceftobiprole included headache and gastrointestinal upset. CONCLUSION: Ceftobiprole is a novel, broad-spectrum, parenteral cephalosporin undergoing Phase III clinical trials. Its broad spectrum of activity makes it a candidate for monotherapy of cSSSIs and pneumonias that have required combination therapy in the past.

ESR dating pleistocene barnacles from BC and Maine: a new method for tracking sea level change.

Barnacles have never been successfully dated by electron spin resonance (ESR). Living mainly in the intertidal zone, barnacles die when sea level changes cause their permanent exposure. Thus, dating the barnacles dates past sea level changes. From this, we can measure apparent sea level changes that occur due to ocean volume changes, crustal isostasy, and tectonics. ESR can date aragonitic mollusc shells ranging in age from 5 ka to at least 500 ka. By modifying the standard ESR method for molluscs to chemically dissolve 20 microm from off the shells, six barnacle samples from Norridgewock, Maine, and Khyex River, British Columbia, were tested for suitability for ESR dating. Due to Mn2+ interference peaks, the four Maine barnacle samples were not datable by ESR. Two barnacles from BC, which lacked Mn2+ interference, yielded a mean ESR age of 15.1 +/- 1.0 ka. These ages agree well with 14C dates on the barnacles themselves and wood in the overlying glaciomarine sediment. Although stability tests to calculate the mean dating signal lifetime and more ESR calibration tests against other barnacles of known age are needed to ensure the method's accuracy, ESR can indeed date Balanus, and thus, sea level changes.

Polymer underlayer assisted dewetting of a top metal nanofilm.

We demonstrated polymethylmethacrylate (PMMA) polymer underlayer assisted, focused-ion-beam (FIB)-induced dewetting of a top Au nanofilm where we found that the underlayer played a prominent and, in some cases, a useful role in the dewetting of the top layer. For an Au nanofilm deposited on a thick uniform PMMA underlayer, where the underlayer is stable and therefore does not dewet, irregularly spaced Au nanoparticles (AuNPs) were formed as expected by raster-scanning of a focused Ga-ion beam. On the other hand, topographically pre-patterned thin PMMA film provided heterogeneous nucleation sites for both the Au top layer and the PMMA underlayer to initiate dewetting at and guidance for forming regularly spaced AuNPs with much narrower size distribution at significantly lower ion dose levels when compared to the thick, uniform underlayer case. We also found that the underlayer assisted dewetting in this case relaxes the restriction on pre-pattern periodicity to obtain a single NP per pattern period, which is a noteworthy departure from the pre-patterned solid substrate case. FIB-induced AuNP areas can have sharp boundaries and can be positioned on a selected area of a substrate with high positional accuracy, which is important for the implementation of devices in sensing, nano-optics/photonics, and optoelectronic applications.

Acute seizures in a patient receiving divalproex sodium after starting ertapenem therapy.

Divalproex sodium is an anticonvulsant widely prescribed to treat several types of seizure disorders, including tonic-clonic and simple or complex partial seizures. We describe a 41-year-old man who experienced recurring tonic-clonic seizures after a drug interaction between divalproex sodium and ertapenem, a carbapenem antibiotic. The patient's valproic acid serum concentration was 130 mug/ml approximately 3 months before he started ertapenem 2000 mg/day (20.6 mg/kg/day). On day 7 of ertapenem therapy, the patient was brought to the emergency department with tonic-clonic seizures; his valproic acid serum concentration was 70 microg/ml. His divalproex sodium dosage was increased, and he was released from the emergency department only to return 4 days later with recurring seizures. This time his valproic acid serum concentration was 10.7 microg/ml. Ertapenem was discontinued, and his divalproex sodium dosage was increased further. The patient's valproic acid level rapidly returned to a therapeutic level 2 days after ertapenem discontinuation, and he had no further seizures. Using the Naranjo adverse drug reaction probability scale to determine the probability of the drug interaction, we found that the likelihood of the interaction was probable (score of 7). Similar interactions have been reported between other carbapenem antibiotics and valproic acid. Clinicians should be aware of this potential interaction between divalproex sodium and ertapenem; concurrent administration of these two drugs should be approached with caution. In patients prescribed this combination, the valproic acid serum concentration should be carefully monitored to prevent recurring seizures.

Disruption of the zinc finger motifs in the Leishmania tarentolae LC-4 (=TbMP63) L-complex editing protein affects the stability of the L-complex.

The uridine insertion/deletion editing complex, which we have termed the L-complex, is composed of at least 16 polypeptides stabilized entirely by protein-protein interactions. Three L-complex proteins contain zinc finger motifs that could be involved in these interactions. In Leishmania these proteins are labeled LC-1, LC-4, and LC-7b, and the orthologs in Trypanosoma brucei are labeled MP81, MP63, and MP42. Overexpression of TAP-tagged LC-4 in Leishmania tarentolae led to a partial localization of the protein in the L-complex together with the endogenous LC-4 protein, suggesting at least a dimeric organization. Disruption of zinc fingers 1 or 2 (ZnF-1 and ZnF-2) in the tagged LC-4 protein was performed by mutation of the two zinc-binding cysteines to glycines. Disruption of ZnF-1 led to a partial growth defect and a substantive breakdown of the L-complex, whereas disruption of ZnF-2 had no effect on cell growth and caused a partial breakdown of the L-complex. A close interaction of LC-4 with 2-4 proteins, including REL1 (RNA ligase) and LC-3, was suggested by chemical crosslinking and co-immunoprecipitation experiments. Our results suggest that both ZnF-1 and ZnF-2 in LC-4 play a role in protein-protein interactions and indicate that the LC-4 subcomplex may be required for formation or stability of the entire L-complex.

Liquid chromatography-tandem mass spectrometry assay for simultaneous measurement of estradiol and estrone in human plasma.

BACKGROUND: Estradiol (E2) and estrone (E1) measurements form an integral part of the assessment of female reproductive function and have expanding roles in other fields. However, many E1 and E2 immunoassays have limited functional sensitivity, suffer from cross-reactivity, and display poor intermethod agreement. To overcome these problems, we developed a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay for the simultaneous measurement of E1 and E2. METHODS: After dansyl chloride derivatization, samples were separated by fast gradient chromatography and injected into a tandem mass spectrometer after formation of positive ions with atmospheric pressure chemical ionization. The limits of detection and quantification, recovery, linearity, precision, and reference intervals were determined, and performance was compared with several immunoassays. RESULTS: Total run time per sample was 5 min. The multiple-reaction monitoring ion pairs were m/z 506/171 for 3-dansyl-estradiol and m/z 504/171 for 3-dansyl-estrone. The limits of detection for E1 and E2 were 12.9 pmol/L (3.5 ng/L) and 10.3 pmol/L (2.8 ng/L), respectively. Interassay imprecision (CV) was 4-20% (n = 20). The limits of quantification (functional sensitivities) for E1 and E2 were 44.1 pmol/L (11.9 ng/L) and 23.2 pmol/L (6.3 ng/L), respectively. The assay was linear to >2200 pmol/L ( approximately 600 ng/L) for each analyte. Recoveries were 93-108% for E1 and 100-110% for E2. No cross-reactivity was observed. Method comparison with several immunoassays revealed that the latter were inaccurate and prone to interferences at low E1 and E2 concentrations. CONCLUSIONS: LC-MS/MS allows rapid, simultaneous, sensitive, and accurate quantification of E1 and E2 in human serum.

Isolation of a U-insertion/deletion editing complex from Leishmania tarentolae mitochondria.

A multiprotein, high molecular weight complex active in both U-insertion and U-deletion as judged by a pre-cleaved RNA editing assay was isolated from mitochondrial extracts of Leishmania tarentolae by the tandem affinity purification (TAP) procedure, using three different TAP-tagged proteins of the complex. This editing- or E-complex consists of at least three protein-containing components interacting via RNA: the RNA ligase-containing L-complex, a 3' TUTase (terminal uridylyltransferase) and two RNA-binding proteins, Ltp26 and Ltp28. Thirteen approximately stoichiometric components were identified by mass spectrometric analysis of the core L-complex: two RNA ligases; homologs of the four Trypanosoma brucei editing proteins; and seven novel polypeptides, among which were two with RNase III, one with an AP endo/exonuclease and one with nucleotidyltransferase motifs. Three proteins have no similarities beyond kinetoplastids.

A 100-kD complex of two RNA-binding proteins from mitochondria of Leishmania tarentolae catalyzes RNA annealing and interacts with several RNA editing components.

A stable 100-kD complex from mitochondria of Leishmania tarentolae containing two RNA-binding proteins, Ltp26 and Ltp28, was identified by cross-linking to unpaired 4-thiouridine nucleotides in a partially duplex RNA substrate. The genes were cloned and expressed and the complex was reconstituted from recombinant proteins in the absence of RNA or additional factors. The Ltp26 and Ltp28 proteins are homologs of gBP27 and gBP29 from Crithidia fasciculata and gBP25 and gBP21 from Trypanosoma brucei, respectively. The purified Ltp26/Ltp28 complex, the individual recombinant proteins, and the reconstituted complex are each capable of catalyzing the annealing of complementary RNAs, as was previously shown for gBP21 from T. brucei. A high-molecular-weight RNP complex consisting of the Ltp26/Ltp28 complex and several 55-60-kD proteins together with guide RNA could be purified from mitochondrial extract of L. tarentolae transfected with Ltp28-TAP. This complex also interacted in a less stable manner with the RNA ligase-containing L-complex and with the 3' TUTase. The Ltp26/Ltp28 RNP complex is a candidate for catalyzing the annealing of guide RNA and pre-edited mRNA in the initial step of RNA editing.

A comparison of BTA stat, hemoglobin dipstick, telomerase and Vysis UroVysion assays for the detection of urothelial carcinoma in urine.

PURPOSE: We determine the sensitivity and specificity of various assays for the detection of urothelial carcinoma. MATERIALS AND METHODS: A total of 280 voided urine specimens from 265 patients were obtained immediately before cystoscopy for BTA stat, (Bard Diagnostic, Redmond, Washington) hemoglobin dipstick, (Bayer, Elkhart, Indiana) telomerase and UroVysion (Vysis, a wholly owned subsidiary of Abbott Laboratories, Abbott Park, Illinois) analysis. RESULTS: Of the 265 patients 75 had biopsy proven urothelial carcinoma, and the sensitivity of the assays was determined from these patients. From most sensitive to least sensitive, the overall sensitivity of UroVysion (73 cases), BTA stat (72), hemoglobin dipstick (73) and telomerase (70) was 81%, 78%, 74%, and 46%, respectively. Each of the first 3 tests was statistically significantly more sensitive than the telomerase assay (p <0.05). However, the differences in overall sensitivity of UroVysion, BTA stat and hemoglobin dipstick were not statistically significant. The specificity of the tests was calculated for 80 of the 265 patients in this study who had no history of urothelial carcinoma and negative cystoscopy findings despite common urological complaints. From most specific to least specific, the specificity of UroVysion, telomerase, BTA stat and hemoglobin dipstick was 96%, 91%, 74% and 51%, respectively. UroVysion and telomerase were statistically significantly (p <0.01) more specific than the BTA stat and hemoglobin dipstick assays, and all of the assays were more specific than hemoglobin dipstick testing (p <0.001). CONCLUSIONS: Our study reveals that UroVysion is the most sensitive and specific assay among those tested for the detection of urothelial carcinoma. Telomerase testing had good specificity but poor sensitivity. The BTA stat and hemoglobin dipstick tests had good sensitivity but relatively poor specificity. UroVysion is a promising new assay for the detection of urothelial carcinoma in urine specimens. However, further studies are needed to explore the role of the various assays in the treatment of patients with superficial urothelial carcinoma.