Process evaluation of counseling delivered by a patient navigator in an efficacious smoking cessation intervention among low-income primary care patients.

INTRODUCTION: This exploratory study examined the relationship between receipt of counseling by a patient navigator and socio-demographic characteristics of primary care patients enrolled in a smoking cessation trial. METHODS: We grouped intervention participants (n = 177) into two categories: 1) no or some contact with the navigator or 2) minimum counseling intervention dose or higher delivered. RESULTS: In logistic regression analyses, controlling for patient race/ethnicity, education, age, gender, household annual income, stress/chaos/hassles composite score, heavy smoking, and substance use, non-Hispanic white participants had lower odds (aOR 0.30; 95% CI 0.13-0.70, p < 0.01) of receiving the minimum intervention dose or higher compared to all other race/ethnicity categories. There was also effect modification such that patients aged 50 or younger who were non-Hispanic white were less likely (aOR 0.09, 95% CI: 0.02-0.54, p < 0.01) to receive the minimum intervention dose compared to older patients from all other race/ethnicity groups. CONCLUSIONS: Future research should explore issues such as acceptability of the intervention to white and younger age participants, and the potential impact of co-occurring substance use disorders on intervention uptake.

Inhibition of Cyclin-Dependent Kinase 5: A Strategy to Improve Sorafenib Response in Hepatocellular Carcinoma Therapy.

Therapeutic options for patients with advanced-stage hepatocellular carcinoma (HCC) are very limited. The only approved first-line treatment is the multi-tyrosine kinase inhibitor sorafenib, which shows low response rates and severe side effects. In particular, the compensatory activation of growth factor receptors leads to chemoresistance and limits the clinical impact of sorafenib. However, combination approaches to improve sorafenib have failed. Here we investigate the inhibition of cyclin-dependent kinase 5 (Cdk5) as a promising combination strategy to improve sorafenib response in HCC. Combination of sorafenib with Cdk5 inhibition (genetic knockdown by short hairpin RNA or CRISPR/Cas9 and pharmacologic inhibition) synergistically impaired HCC progression in vitro and in vivo by inhibiting both tumor cell proliferation and migration. Importantly, these effects were mediated by a mechanism for Cdk5: A liquid chromatography-tandem mass spectrometry-based proteomic approach revealed that Cdk5 inhibition interferes with intracellular trafficking, a process crucial for cellular homeostasis and growth factor receptor signaling. Cdk5 inhibition resulted in an accumulation of enlarged vesicles and respective cargos in the perinuclear region, considerably impairing the extent and quality of growth factor receptor signaling. Thereby, Cdk5 inhibition offers a comprehensive approach to globally disturb growth factor receptor signaling that is superior to specific inhibition of individual growth factor receptors. Conclusion: Cdk5 inhibition represents an effective approach to improve sorafenib response and to prevent sorafenib treatment escape in HCC. Notably, Cdk5 is an addressable target frequently overexpressed in HCC, and with Dinaciclib, a clinically tested Cdk5 inhibitor is readily available. Thus, our study provides evidence for clinically evaluating the combination of sorafenib and Dinaciclib to improve the therapeutic situation for patients with advanced-stage HCC.

Targeting de novo lipogenesis as a novel approach in anti-cancer therapy.

BACKGROUND: Although altered membrane physiology has been discussed within the context of cancer, targeting membrane characteristics by drugs being an attractive therapeutic strategy has received little attention so far. METHODS: Various acetyl-CoA carboxylase 1 (ACC1), and fatty acid synthase (FASN) inhibitors (like Soraphen A and Cerulenin) as well as genetic knockdown approaches were employed to study the effects of disturbed phospholipid composition on membrane properties and its functional impact on cancer progression. By using state-of-the-art methodologies such as LC-MS/MS, optical tweezers measurements of giant plasma membrane vesicles and fluorescence recovery after photobleaching analysis, membrane characteristics were examined. Confocal laser scanning microscopy, proximity ligation assays, immunoblotting as well as migration, invasion and proliferation experiments unravelled the functional relevance of membrane properties in vitro and in vivo. RESULTS: By disturbing the deformability and lateral fluidity of cellular membranes, the dimerisation, localisation and recycling of cancer-relevant transmembrane receptors is compromised. Consequently, impaired activation of growth factor receptor signalling cascades results in abrogated tumour growth and metastasis in different in vitro and in vivo models. CONCLUSIONS: This study highlights the field of membrane properties as a promising druggable cellular target representing an innovative strategy for development of anti-cancer agents.

Inhibition of Cdk5 induces cell death of tumor-initiating cells.

BACKGROUND: Tumour-initiating cells (TICs) account for chemoresistance, tumour recurrence and metastasis, and therefore represent a major problem in tumour therapy. However, strategies to address TICs are limited. Recent studies indicate Cdk5 as a promising target for anti-cancer therapy and Cdk5 has recently been associated with epithelial-mesenchymal transition (EMT). However, a role of Cdk5 in TICs has not been described yet. METHODS: Expression of Cdk5 in human cancer tissue was analysed by staining of a human tissue microarray (TMA). Functional effects of Cdk5 overexpression, genetic knockdown by siRNA and shRNA, and pharmacologic inhibition by the small molecule roscovitine were tested in migration, invasion, cell death, and tumorsphere assays and in tumour establishment in vivo. For mechanistic studies, molecular biology methods were applied. RESULTS: In fact, here we pin down a novel function of Cdk5 in TICs: knockdown and pharmacological inhibition of Cdk5 impaired tumorsphere formation and reduced tumour establishment in vivo. Conversely, Cdk5 overexpression promoted tumorsphere formation which was in line with increased expression of Cdk5 in human breast cancer tissues as shown by staining of a human TMA. In order to understand how Cdk5 inhibition affects tumorsphere formation, we identify a role of Cdk5 in detachment-induced cell death: Cdk5 inhibition induced apoptosis in tumorspheres by stabilizing the transcription factor Foxo1 which results in increased levels of the pro-apoptotic protein Bim. CONCLUSIONS: In summary, our study elucidates a Cdk5-Foxo1-Bim pathway in cell death in tumorspheres and suggests Cdk5 as a potential target to address TICs.

Two-Pore Channel Function Is Crucial for the Migration of Invasive Cancer Cells.

Metastatic invasion is the major cause of cancer-related deaths. In this study, we introduce two-pore channels (TPC), a recently described class of NAADP- and PI(3,5)P2-sensitive Ca2+-permeable cation channels in the endolysosomal system of cells, as candidate targets for the treatment of invasive cancers. Inhibition of the channel abrogated migration of metastatic cancer cells in vitro Silencing or pharmacologic inhibition of the two-pore channel TPC2 reduced lung metastasis of mammary mouse cancer cells. Disrupting TPC function halted trafficking of ß1-integrin, leading to its accumulation in EEA1-positive early endosomes. As a consequence, invasive cancer cells were no longer able to form leading edges, which are required for adequate migration. Our findings link TPC to cancer cell migration and provide a preclinical proof of concept for their candidacy as targets to treat metastatic cancers. Cancer Res; 77(6); 1427-38. ©2017 AACR.

V-ATPase inhibition increases cancer cell stiffness and blocks membrane related Ras signaling - a new option for HCC therapy.

Hepatocellular carcinoma (HCC) is the fifth most frequent cancer worldwide and the third leading cause of cancer-related death. However, therapy options are limited leaving an urgent need to develop new strategies. Currently, targeting cancer cell lipid and cholesterol metabolism is gaining interest especially regarding HCC. High cholesterol levels support proliferation, membrane-related mitogenic signaling and increase cell softness, leading to tumor progression, malignancy and invasive potential. However, effective ways to target cholesterol metabolism for cancer therapy are still missing. The V-ATPase inhibitor archazolid was recently shown to interfere with cholesterol metabolism. In our study, we report a novel therapeutic potential of V-ATPase inhibition in HCC by altering the mechanical phenotype of cancer cells leading to reduced proliferative signaling. Archazolid causes cellular depletion of free cholesterol leading to an increase in cell stiffness and membrane polarity of cancer cells, while hepatocytes remain unaffected. The altered membrane composition decreases membrane fluidity and leads to an inhibition of membrane-related Ras signaling resulting decreased proliferation in vitro and in vivo. V-ATPase inhibition represents a novel link between cell biophysical properties and proliferative signaling selectively in malignant HCC cells, providing the basis for an attractive and innovative strategy against HCC.

MDM2 antagonist nutlin-3a sensitizes tumors to V-ATPase inhibition.

Treating cancer is one of the big challenges of this century and it has become evident that single chemotherapeutic treatment is rarely effective. As tumors often carry multiple mutations using combination therapy which addresses different targets seems therefore more beneficial. One of the most frequently mutated genes in tumors is the tumor suppressor p53. Significant work has been put in the development of p53 activators, which are now in clinical studies against diverse cancers. Recently, we could show that inhibition of V-ATPase, a multisubunit proton pump, by archazolid induces p53 protein levels in cancer cells. In this study, we provide evidence that the combination of archazolid with the p53 activator nutlin-3a is synergistically inducing cell death in different p53 wild type tumor cell lines. Mechanistically, this effect could presumably be attributed to reduction of glycolysis as TIGAR mRNA levels were increased and glucose uptake and Glut1 protein levels were reduced. In addition, combination treatment highly activated pro-apoptotic pathways including IGFBP3 and Bax inducing caspase-9 and PARP cleavage. Remarkably, combination of archazolid and nutlin-3a was more efficient in reducing tumor growth compared to single dose treatment in a U87MG mouse model in vivo. Hence, our findings suggest the combination of archazolid and nutlin-3a as a highly promising strategy for the treatment of p53 wild type tumors.

Inhibition of endothelial Cdk5 reduces tumor growth by promoting non-productive angiogenesis.

Therapeutic success of VEGF-based anti-angiogenic tumor therapy is limited due to resistance. Thus, new strategies for anti-angiogenic cancer therapy based on novel targets are urgently required. Our previous in vitro work suggested that small molecule Cdk5 inhibitors affect angiogenic processes such as endothelial migration and proliferation. Moreover, we recently uncovered a substantial role of Cdk5 in the development of lymphatic vessels. Here we pin down the in vivo impact of endothelial Cdk5 inhibition in angiogenesis and elucidate the underlying mechanism in order to judge the potential of Cdk5 as a novel anti-angiogenic and anti-cancer target. By the use of endothelial-specific Cdk5 knockout mouse models and various endothelial and tumor cell based assays including human tumor xenograft models, we show that endothelial-specific knockdown of Cdk5 results in excessive but non-productive angiogenesis during development but also in tumors, which subsequently leads to inhibition of tumor growth. As Cdk5 inhibition disrupted Notch function by reducing the generation of the active Notch intracellular domain (NICD) and Cdk5 modulates Notch-dependent endothelial cell proliferation and sprouting, we propose that the Dll4/Notch driven angiogenic signaling hub is an important and promising mechanistic target of Cdk5. In fact, Cdk5 inhibition can sensitize tumors to conventional anti-angiogenic treatment as shown in tumor xenograft models. In summary our data set the stage for Cdk5 as a drugable target to inhibit Notch-driven angiogenesis condensing the view that Cdk5 is a promising target for cancer therapy.

Characterization of the murine macrophage response to infection with virulent and avirulent Burkholderia species.

BACKGROUND: Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Gram-negative facultative intracellular pathogens, which are the causative agents of melioidosis and glanders, respectively. Depending on the route of exposure, aerosol or transcutaneous, infection by Bp or Bm can result in an extensive range of disease - from acute to chronic, relapsing illness to fatal septicemia. Both diseases are associated with difficult diagnosis and high fatality rates. About ninety five percent of patients succumb to untreated septicemic infections and the fatality rate is 50 % even when standard antibiotic treatments are administered. RESULTS: The goal of this study is to profile murine macrophage-mediated phenotypic and molecular responses that are characteristic to a collection of Bp, Bm, Burkholderia thailandensis (Bt) and Burkholderia oklahomensis (Bo) strains obtained from humans, animals, environment and geographically diverse locations. Burkholderia spp. (N = 21) were able to invade and replicate in macrophages, albeit to varying degrees. All Bp (N = 9) and four Bm strains were able to induce actin polymerization on the bacterial surface following infection. Several Bp and Bm strains showed reduced ability to induce multinucleated giant cell (MNGC) formation, while Bo and Bp 776 were unable to induce this phenotype. Measurement of host cytokine responses revealed a statistically significant Bm mediated IL-6 and IL-10 production compared to Bp strains. Hierarchical clustering of transcriptional data from 84 mouse cytokines, chemokines and their corresponding receptors identified 29 host genes as indicators of differential responses between the Burkholderia spp. Further validation confirmed Bm mediated Il-1b, Il-10, Tnfrsf1b and Il-36a mRNA expressions were significantly higher when compared to Bp and Bt. CONCLUSIONS: These results characterize the phenotypic and immunological differences in the host innate response to pathogenic and avirulent Burkholderia strains and provide insight into the phenotypic alterations and molecular targets underlying host-Burkholderia interactions.

Vacuolar-ATPase Inhibition Blocks Iron Metabolism to Mediate Therapeutic Effects in Breast Cancer.

Generalized strategies to improve breast cancer treatment remain of interest to develop. In this study, we offer preclinical evidence of an important metabolic mechanism underlying the antitumor activity of inhibitors of the vacuolar-type ATPase (V-ATPase), a heteromultimeric proton pump. Specifically, our investigations in the 4T1 model of metastatic breast cancer of the V-ATPase inhibitor archazolid suggested that its ability to trigger metabolic stress and apoptosis associated with tumor growth inhibition related to an interference with hypoxia-inducible factor-1α signaling pathways and iron metabolism. As a consequence of disturbed iron metabolism, archazolid caused S-phase arrest, double-stranded DNA breaks, and p53 stabilization, leading to apoptosis. Our findings link V-ATPase to cell-cycle progression and DNA synthesis in cancer cells, and highlight the basis for the clinical exploration of V-ATPase as a potentially generalizable therapy for breast cancer.

Characterization of the Burkholderia thailandensis SOS response by using whole-transcriptome shotgun sequencing.

The bacterial SOS response is a well-characterized regulatory network encoded by most prokaryotic bacterial species and is involved in DNA repair. In addition to nucleic acid repair, the SOS response is involved in pathogenicity, stress-induced mutagenesis, and the emergence and dissemination of antibiotic resistance. Using high-throughput sequencing technology (SOLiD RNA-Seq), we analyzed the Burkholderia thailandensis global SOS response to the fluoroquinolone antibiotic, ciprofloxacin (CIP), and the DNA-damaging chemical, mitomycin C (MMC). We demonstrate that a B. thailandensis recA mutant (RU0643) is ∼4-fold more sensitive to CIP in contrast to the parental strain B. thailandensis DW503. Our RNA-Seq results show that CIP and MMC treatment (P < 0.01) resulted in the differential expression of 344 genes in B. thailandensis and 210 genes in RU0643. Several genes associated with the SOS response were induced and include lexA, uvrA, dnaE, dinB, recX, and recA. At the genome-wide level, we found an overall decrease in gene expression, especially for genes involved in amino acid and carbohydrate transport and metabolism, following both CIP and MMC exposure. Interestingly, we observed the upregulation of several genes involved in bacterial motility and enhanced transcription of a B. thailandensis genomic island encoding a Siphoviridae bacteriophage designated E264. Using B. thailandensis plaque assays and PCR with B. mallei ATCC 23344 as the host, we demonstrate that CIP and MMC exposure in B. thailandensis DW503 induces the transcription and translation of viable bacteriophage in a RecA-dependent manner. This is the first report of the SOS response in Burkholderia spp. to DNA-damaging agents. We have identified both common and unique adaptive responses of B. thailandensis to chemical stress and DNA damage.

Integrating high-content imaging and chemical genetics to probe host cellular pathways critical for Yersinia pestis infection.

The molecular machinery that regulates the entry and survival of Yersinia pestis in host macrophages is poorly understood. Here, we report the development of automated high-content imaging assays to quantitate the internalization of virulent Y. pestis CO92 by macrophages and the subsequent activation of host NF-κB. Implementation of these assays in a focused chemical screen identified kinase inhibitors that inhibited both of these processes. Rac-2-ethoxy-3 octadecanamido-1-propylphosphocholine (a protein Kinase C inhibitor), wortmannin (a PI3K inhibitor), and parthenolide (an IκB kinase inhibitor), inhibited pathogen-induced NF-κB activation and reduced bacterial entry and survival within macrophages. Parthenolide inhibited NF-κB activation in response to stimulation with Pam3CSK4 (a TLR2 agonist), E. coli LPS (a TLR4 agonist) or Y. pestis infection, while the PI3K and PKC inhibitors were selective only for Y. pestis infection. Together, our results suggest that phagocytosis is the major stimulus for NF-κB activation in response to Y. pestis infection, and that Y. pestis entry into macrophages may involve the participation of protein kinases such as PI3K and PKC. More importantly, the automated image-based screening platform described here can be applied to the study of other bacteria in general and, in combination with chemical genetic screening, can be used to identify host cell functions facilitating the identification of novel antibacterial therapeutics.

Identification of a surrogate marker for infection in the African green monkey model of inhalation anthrax.

In 2001, a bioterrorism attack involving Bacillus anthracis spore-laced letters resulted in 22 cases of inhalation anthrax, with five fatalities. This incident identified gaps in our health care system and precipitated a renewed interest in identifying both therapeutics and rapid diagnostic assays. To address those gaps, well-characterized animal models that resemble the human disease are needed. In addition, a rapid assay for a reliable diagnostic marker is key to the success of these efforts. In this study, we exposed African green monkeys to B. anthracis spores; examined clinical signs and physiological parameters, including fever, heart rate, complete blood count, and bacteremia; and evaluated the PCR assay and electrochemiluminescence (ECL) immunoassay for the biomarkers protective antigen and capsule. The results demonstrated that although there were neither objective clinical nor physiological signs that consistently identified either infection or the onset of clinical anthrax disease, the African green monkey is a suitable animal model exhibiting a disease course similar to that observed in the rhesus model and humans. We also demonstrated that detection of the biomarkers protective antigen and capsule correlated with bacterial loads in the blood of these nonhuman primates. The ECL immunoassay described here is simple and sensitive enough to provide results in one to two hours, making this assay a viable option for use in the diagnosis of anthrax, leading to timely initiation of treatment, which is a key component of B. anthracis therapeutic development.

Tax1-binding protein 1 is expressed in the retina and interacts with the GABA(C) receptor rho1 subunit.

Macromolecular signalling complexes that link neurotransmitter receptors to functionally and structurally associated proteins play an important role in the regulation of neurotransmission. Thus the identification of proteins binding to neurotransmitter receptors describes molecular mechanisms of synaptic signal transduction. To identify interacting proteins of GABA(C) (where GABA is gamma-aminobutyric acid) receptors in the retina, we used antibodies specific for GABA(C) receptor rho1-3 subunits. Analysis of immunoprecipitated proteins by MALDI-TOF MS (matrix-assisted laser-desorption ionization-time-of-flight MS) identified the liver regeneration-related protein 2 that is identical with amino acids 253-813 of the Tax1BP1 (Tax1-binding protein 1). A C-terminal region of Tax1BP1 bound to an intracellular domain of the rho1 subunit, but not to other subunits of GABA(C), GABA(A) or glycine receptors. Confocal laser-scanning microscopy demonstrated co-localization of Tax1BP1 and rho1 in clusters at the cell membrane of transfected cells. Furthermore, Tax1BP1 and GABA(C) receptors were co-expressed in both synaptic layers of the retina, indicating that Tax1BP1 is a component of GABA(C) receptor-containing signal complexes.

Live vaccine strain Francisella tularensis is detectable at the inoculation site but not in blood after vaccination against tularemia.

INTRODUCTION: Live vaccine strain (LVS) Francisella tularensis is a live, attenuated investigational tularemia vaccine that has been used by the US Army for decades to protect laboratory workers. Postvaccination bacterial kinetic characteristics of LVS at the inoculation site and in the blood are unknown and, therefore, were assessed in a prospective study. LVS vaccination of laboratory workers provided the opportunity to compare culture with polymerase chain reaction (PCR) for the detection of F. tularensis in human clinical samples. METHODS: Blood and skin swab samples were prospectively collected from volunteers who received the LVS tularemia vaccine at baseline (negative controls) and at 5 specified time points (days 1, 2, 7 or 8, 14 or 15, and 35 after vaccination). Bacterial culture and PCR of whole blood samples (17 volunteers) and inoculation site swabs (41 volunteers) were performed. RESULTS: The culture and PCR results of all blood samples were negative. Results of real-time PCR from the inoculation site samples were positive for 41 (100%) of 41 volunteers on day 1, for 40 (97.6%) of 41 volunteers on day 2, for 24 (58.5%) of 41 on day 7 or 8, for 6 (16.7%) of 36 on day 14 or 15, and for 0 (0%) of 9 on day 35. Positive results of bacterial cultures of the inoculation site samples occurred significantly less frequently, compared with PCR testing, with 4 (9.8%) of 41 volunteers having positive results on day 1 (P<.001) and 4 (9.8%) of 41 on day 2 (P<.001); all results from subsequent days were negative. CONCLUSIONS: F. tularensis LVS genomic DNA was detected in the majority of samples from the inoculation site up to 1 week after LVS vaccination, with real-time PCR being more sensitive than culture. Our data suggest that bacteremia does not occur after LVS vaccination in normal, healthy human volunteers.

Cynomolgus macaque as an animal model for severe acute respiratory syndrome.

BACKGROUND: The emergence of severe acute respiratory syndrome (SARS) in 2002 and 2003 affected global health and caused major economic disruption. Adequate animal models are required to study the underlying pathogenesis of SARS-associated coronavirus (SARS-CoV) infection and to develop effective vaccines and therapeutics. We report the first findings of measurable clinical disease in nonhuman primates (NHPs) infected with SARS-CoV. METHODS AND FINDINGS: In order to characterize clinically relevant parameters of SARS-CoV infection in NHPs, we infected cynomolgus macaques with SARS-CoV in three groups: Group I was infected in the nares and bronchus, group II in the nares and conjunctiva, and group III intravenously. Nonhuman primates in groups I and II developed mild to moderate symptomatic illness. All NHPs demonstrated evidence of viral replication and developed neutralizing antibodies. Chest radiographs from several animals in groups I and II revealed unifocal or multifocal pneumonia that peaked between days 8 and 10 postinfection. Clinical laboratory tests were not significantly changed. Overall, inoculation by a mucosal route produced more prominent disease than did intravenous inoculation. Half of the group I animals were infected with a recombinant infectious clone SARS-CoV derived from the SARS-CoV Urbani strain. This infectious clone produced disease indistinguishable from wild-type Urbani strain. CONCLUSIONS: SARS-CoV infection of cynomolgus macaques did not reproduce the severe illness seen in the majority of adult human cases of SARS; however, our results suggest similarities to the milder syndrome of SARS-CoV infection characteristically seen in young children.

Using real-time PCR to specifically detect Burkholderia mallei.

Burkholderia mallei is the causative agent of human and animal glanders and is a category B biothreat agent. Rapid diagnosis of B. mallei and immediate prophylactic treatment are essential for patient survival. The majority of current bacteriological and immunological techniques for identifying B. mallei from clinical samples are time-consuming, and cross-reactivity with closely related organisms (i.e. Burkholderia pseudomallei) is a problem. In this investigation, two B. mallei-specific real-time PCR assays targeting the B. mallei bimA(ma) gene (Burkholderia intracellular motility A; BMAA0749), which encodes a protein involved in actin polymerization, were developed. The PCR primer and probe sets were tested for specificity against a collection of B. mallei and B. pseudomallei isolates obtained from numerous clinical and environmental (B. pseudomallei only) sources. The assays were also tested for cross-reactivity using template DNA from 14 closely related Burkholderia species. The relative limit of detection for the assays was found to be 1 pg or 424 genome equivalents. The authors also analysed the applicability of assays to detect B. mallei within infected BALB/c mouse tissues. Beginning 1 h post aerosol exposure, B. mallei was successfully identified within the lungs, and starting at 24 h post exposure, in the spleen and liver. Surprisingly, B. mallei was not detected in the blood of acutely infected animals. This investigation provides two real-time PCR assays for the rapid and specific identification of B. mallei.

Development of a polymerase chain reaction assay for the specific identification of Burkholderia mallei and differentiation from Burkholderia pseudomallei and other closely related Burkholderiaceae.

Burkholderia mallei and Burkholderia pseudomallei, the etiologic agents responsible for glanders and melioidosis, respectively, are genetically and phenotypically similar and are category B biothreat agents. We used an in silico approach to compare the B. mallei ATCC 23344 and B. pseudomallei K96243 genomes to identify nucleotide sequences unique to B. mallei. Five distinct B. mallei DNA sequences and/or genes were identified and evaluated for polymerase chain reaction (PCR) assay development. Genomic DNAs from a collection of 31 B. mallei and 34 B. pseudomallei isolates, obtained from various geographic, clinical, and environmental sources over a 70-year period, were tested with PCR primers targeted for each of the B. mallei ATCC 23344-specific nucleotide sequences. Of the 5 chromosomal targets analyzed, only PCR primers designed to bimA(Bm) were specific for B. mallei. These primers were used to develop a rapid PCR assay for the definitive identification of B. mallei and differentiation from all other bacteria.

Real-time PCR assays targeting a unique chromosomal sequence of Yersinia pestis.

BACKGROUND: Yersinia pestis, the causative agent of the zoonotic infection plague, is a major concern as a potential bioweapon. Current real-time PCR assays used for Y. pestis detection are based on plasmid targets, some of which may generate false-positive results. METHODS: Using the yp48 gene of Y. pestis, we designed and tested 2 real-time TaqMan minor groove binder (MGB) assays that allowed us to use chromosomal genes as both confirmatory and differential targets for Y. pestis. We also designed several additional assays using both Simple-Probe and MGB Eclipse probe technologies for the selective differentiation of Yersinia pseudotuberculosis from Y. pestis. These assays were designed around a 25-bp insertion site recently identified within the yp48 gene of Y. pseudotuberculosis. RESULTS: The Y. pestis-specific assay distinguished this bacterium from other Yersinia species but had unacceptable low-level detection of Y. pseudotuberculosis, a closely related species. Simple-Probe and MGB Eclipse probes specific for the 25-bp insertion detected only Y. pseudotuberculosis DNA. Probes that spanned the deletion site detected both Y. pestis and Y. pseudotuberculosis DNA, and the 2 species were clearly differentiated by a post-PCR melting temperature (Tm) analysis. The Simple-Probe assay produced an almost 7 degrees C Tm difference and the MGB Eclipse probe a slightly more than 4 degrees C difference. CONCLUSIONS: Our method clearly discriminates Y. pestis DNA from all other Yersinia species tested and from the closely related Y. pseudotuberculosis. These chromosomal assays are important both to verify the presence of Y. pestis based on a chromosomal target and to easily distinguish it from Y. pseudotuberculosis.

Absence of oropharyngeal vaccinia virus after vaccinia (smallpox) vaccination.

BACKGROUND: With the resumption of the vaccinia (smallpox) vaccination, questions regarding transmission risk prompted this study to determine whether vaccinia virus could be detected in the oropharynx of adults recently vaccinated with vaccinia (smallpox) vaccine. German, Russian, and American studies on the oropharyngeal presence of vaccinia virus revealed conflicting results in different age groups. OBJECTIVE: To measure vaccinia viral particle or antigen presence in the oropharynx of adult health care workers after vaccination with vaccinia (smallpox) vaccine using viral culture and high-sensitivity assays (polymerase chain reaction [PCR] and electrochemiluminescence) and to determine whether there is an association between the presence of vaccinia virus and adverse reactions. METHODS: A total of 155 adults (primary vaccinees and revaccinees) were enrolled for 1 baseline and 5 subsequent throat swabs. The swabs were evaluated using viral culture, PCR, and electrochemiluminescence. RESULTS: Of the 155 participants, 144 had more than 2 throat swabs in the 2 weeks after vaccination. Of the 801 specimens evaluated, there were no positive results by culture, PCR, or electrochemiluminescence except in the control samples (n = 6), which were positive by all 3 methods. CONCLUSIONS: Based on the absence of detectable vaccinia virus in this study population, one can be 95% certain that the true rate of vaccinia virus in the oropharynx of adults during the 2 weeks after vaccination with vaccinia (smallpox) vaccine is 0% to 3.3%. These data should be reassuring to the medical community and support the Advisory Committee on Immunization Practice guidelines that respiratory precautions are not necessary after vaccinia (smallpox) vaccination in healthy adults.