Systematic Screening of Penetratin's Protein Targets by Yeast Proteome Microarrays.

Cell-penetrating peptides (CPPs) have distinct properties to translocate across cell envelope. The key property of CPPs to translocation with attached molecules has been utilized as vehicles for the delivery of several potential drug candidates that illustrate the significant effect in in-vitro experiment but fail in in-vivo experiment due to selectively permeable nature of cell envelop. Penetratin, a well-known CPP identified from the third α-helix of Antennapedia homeodomain of Drosophila, has been widely used and studied for the delivery of bioactive molecules to treat cancers, stroke, and infections caused by pathogenic organisms. Few studies have demonstrated that penetratin directly possesses antimicrobial activities against bacterial and fungal pathogens; however, the mechanism is unknown. In this study, we have utilized the power of high-throughput Saccharomyces cerevisiae proteome microarrays to screen all the potential protein targets of penetratin. Saccharomyces cerevisiae proteome microarrays assays of penetratin followed by statistical analysis depicted 123 Saccharomyces cerevisiae proteins as the protein targets of penetratin out of ~5800 Saccharomyces cerevisiae proteins. To understand the target patterns of penetratin, enrichment analyses were conducted using 123 protein targets. In biological process: ribonucleoprotein complex biogenesis, nucleic acid metabolic process, actin filament-based process, transcription, DNA-templated, and negative regulation of gene expression are a few significantly enriched terms. Cytoplasm, nucleus, and cell-organelles are enriched terms for cellular component. Protein-protein interactions network depicted ribonucleoprotein complex biogenesis, cortical cytoskeleton, and histone binding, which represent the major enriched terms for the 123 protein targets of penetratin. We also compared the protein targets of penetratin and intracellular protein targets of antifungal AMPs (Lfcin B, Histatin-5, and Sub-5). The comparison results showed few unique proteins between penetratin and AMPs. Nucleic acid metabolic process and cellular component disassembly were the common enrichment terms for penetratin and three AMPs. Penetratin shows unique enrichment items that are related to DNA biological process. Moreover, motif enrichment analysis depicted different enriched motifs in the protein targets of penetratin, LfcinB, Histatin-5, and Sub-5.

Systematic Analysis of Phosphatidylinositol-5-phosphate-Interacting Proteins Using Yeast Proteome Microarrays.

We used yeast proteome microarrays (∼5800 purified proteins) to conduct a high-throughput and systematic screening of PI5P-interacting proteins with PI5P-tagged fluorescent liposomal nanovesicles. Lissamine rhodamine B-dipalmitoyl phosphatidylethanol was incorporated into the liposome bilayer to provide the nanovesicles with fluorescence without any encapsulants, which not only made the liposome fabrication much easier without the need for purification but also improved the chip-probing quality. A special chip assay was washed very gently without the traditional spin-dry step. Forty-five PI5P-interacting proteins were identified in triplicate with this special chip assay. Subsequently, we used flow cytometry to validate these interactions, and a total of 41 PI5P-interacting proteins were confirmed. Enrichment analysis revealed that these proteins have significant functions associated with ribosome biogenesis, rRNA processing, ribosome binding, GTP binding, and hydrolase activity. Their component enrichment is located in the nucleolus. The InterPro domain analysis indicated that PI5P-interacting proteins are enriched in the P-loop containing nucleoside triphosphate hydrolases domain (P-loop). Additionally, using the MEME program, we identified a consensus motif (IVGPAGTGKSTLF) that contains the Walker A sequence, a well-known nucleotide-binding motif. Furthermore, using a quartz crystal microbalance, both the consensus motif and Walker A motif showed strong affinities to PI5P-containing liposomes but not to PI5P-deprived liposomes or PI-containing liposomes. Additionally, the glycine (G6) and lysine (K7) residues of the Walker A motif (-GPAGTG6K7S-) were found to be critical to the PI5P-binding ability. This study not only identified an additional set of PI5P-interacting proteins but also revealed the strong PI5P-binding affinity (Kd = 1.81 × 10-7 M) of the Walker A motif beyond the motif's nucleotide-binding characteristic.

Systematic Identification of Protein Targets of Sub5 Using Saccharomyces cerevisiae Proteome Microarrays.

Antimicrobial peptides (AMPs) are intensively studied in terms of alternative drugs. Sub5 is a synthetic 12-mer AMP with substitutions of five amino acids of bactenecin 2A (Bac2A), a linear-ized bactenecin variant of bovine. Sub5 is highly effective against fungi with an ability to trans-locate cell membrane, but its targets are unknown. Systematic analysis of Sub5 targets will facil-itate our understanding on its mechanism of action. In this study, we used high-throughput Saccharomyces cerevisiae proteome microarrays to explore the potential protein targets of Sub5. The screening results showed 128 potential protein targets of Sub5. Bioinformatics analysis of protein targets of Sub5 revealed significant gene ontology (GO) enrichment in actin related pro-cess of "actin filament-based process", "actin filament organization", "actin cortical patch or-ganization", regulation of "actin filament bundle assembly". Moreover, the other enriched cat-egories in GO enrichment mostly contained actin associate proteins. In total, 11 actin-associated proteins were identified in the protein targets of Sub5. Protein family (PFAM) enrichment anal-ysis shows protein domain enriched in actin binding, i.e., "Cytoskeletal-regulatory complex EF hand (helix E-loop-helix F motif)". Being consistent with GO analysis, Search Tool for the Re-trieval of Interacting Genes/Proteins (STRING) analysis of the protein targets of Sub5 showed ac-tin network with involvement of 15 protein targets. Along with actin-network, STRING analysis showed protein-protein interaction network in ribonucleoprotein, transcription and translation, chromosome, histone, and ubiquitin related, DNA repair, and chaperone. Multiple Expression motifs for Motif Elicitation (MEME) suite provided a consensus binding motif of [ED][ED]EEE[ED][ED][ED][ED][ED], in total of 75 protein targets of Sub5. This motif was present in 9 out of 15 actin-related proteins identified among protein targets of Sub5.

Systematical Screening of Intracellular Protein Targets of Polyphemusin-I Using Escherichia coli Proteome Microarrays.

With their wide repertoire of mechanisms, antimicrobial peptides (AMPs) are promising alternatives to fight against varied pathogenic microorganisms (bacteria, fungi, viruses, parasites, etc.). AMPs, novel components of the innate immune defense system, are secreted by all organisms. The aquatic environment represents a huge population and an enormous source of varied AMPs. Polyphemusin-I, a marine AMP isolated from hemocytes of an American horseshoe crab, possesses high antimicrobial activities. Studies on polyphemusin-I have verified the intracellular mechanisms of action, however, its intracellular targets are not yet explored. In this study, we employed Escherichia coli proteome microarrays to systematically screen the entire intracellular protein targets of polyphemusin-I. A total of 97 protein targets of polyphemusin-I were statistically analyzed from the quadruplicate Escherichia coli proteome microarrays assays. Among these identified protein targets, 56 proteins had cellular location inside the cell (i.e., cytoplasm), one in the plasma membrane, one in the periplasm and the rest 39 proteins had no specified cellular location. The bioinformatics analysis of these identified protein targets of polyphemusin-I in gene ontology (GO) enrichment category of molecular function revealed significant enrichment in nucleic acid related GO terms i.e., "RNA binding", "nucleotide binding", "nuclease activities", "uracil DNA N-glycosylase activities" and others. Moreover, enrichment in GO category of biological process also depicted enrichment in nucleic acid related GO terms, such as "nucleic acid phosphodiester bond hydrolysis", "deoxyribonucleotide metabolism", and others. In accordance to GO enrichment analysis, protein families (PFAM) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analysis also showed significant enrichment in nucleic acid terms. These enrichment results suggest that polyphemusin-I targets nucleic acid-associated proteins. Furthermore, to provide a comprehensive study, we compared the identified protein targets of polyphemusin-I with previously identified protein targets of four AMPs (P-Der, Lfcin B, PR-39, and Bac 7) using Escherichia coli proteome microarrays. The comparison study of five AMPs (polyhemusin-I, P-Der, Lfcin B, PR-39, and Bac 7) showed only nine common protein targets in all the five AMPs, whereas a total of 39 and 43 common protein targets were identified among the two marine AMPs (polyphemusin-I and P-Der) and three terrestrial AMPs (Lfcin B, PR-39 and Bac7), respectively. To further reveal the target pattern of marine and terrestrial AMPs, the enrichment results obtained from common protein targets of marine AMPs with terrestrial AMPs were compared. The comparison result indicated that AMPs have unique mechanism of action among marine or terrestrial AMPs. Hence, in this study, we have not only identified the intracellular protein targets of polyphemusin-I, but also revealed the protein target differences between marine AMPs and terrestrial AMPs.

Systematical Analysis of the Protein Targets of Lactoferricin B and Histatin-5 Using Yeast Proteome Microarrays.

Antimicrobial peptides (AMPs) have potential antifungal activities; however, their intracellular protein targets are poorly reported. Proteome microarray is an effective tool with high-throughput and rapid platform that systematically identifies the protein targets. In this study, we have used yeast proteome microarrays for systematical identification of the yeast protein targets of Lactoferricin B (Lfcin B) and Histatin-5. A total of 140 and 137 protein targets were identified from the triplicate yeast proteome microarray assays for Lfcin B and Histatin-5, respectively. The Gene Ontology (GO) enrichment analysis showed that Lfcin B targeted more enrichment categories than Histatin-5 did in all GO biological processes, molecular functions, and cellular components. This might be one of the reasons that Lfcin B has a lower minimum inhibitory concentration (MIC) than Histatin-5. Moreover, pairwise essential proteins that have lethal effects on yeast were analyzed through synthetic lethality. A total of 11 synthetic lethal pairs were identified within the protein targets of Lfcin B. However, only three synthetic lethal pairs were identified within the protein targets of Histatin-5. The higher number of synthetic lethal pairs identified within the protein targets of Lfcin B might also be the reason for Lfcin B to have lower MIC than Histatin-5. Furthermore, two synthetic lethal pairs were identified between the unique protein targets of Lfcin B and Histatin-5. Both the identified synthetic lethal pairs proteins are part of the Spt-Ada-Gcn5 acetyltransferase (SAGA) protein complex that regulates gene expression via histone modification. Identification of synthetic lethal pairs between Lfcin B and Histatin-5 and their involvement in the same protein complex indicated synergistic combination between Lfcin B and Histatin-5. This hypothesis was experimentally confirmed by growth inhibition assay.

Systematic Analysis of Intracellular-targeting Antimicrobial Peptides, Bactenecin 7, Hybrid of Pleurocidin and Dermaseptin, Proline-Arginine-rich Peptide, and Lactoferricin B, by Using Escherichia coli Proteome Microarrays.

Antimicrobial peptides (AMPs) act either through membrane lysis or by attacking intracellular targets. Intracellular targeting AMPs are a resource for antimicrobial agent development. Several AMPs have been identified as intracellular targeting peptides; however, the intracellular targets of many of these peptides remain unknown. In the present study, we used an Escherichia coli proteome microarray to systematically identify the protein targets of three intracellular targeting AMPs: bactenecin 7 (Bac7), a hybrid of pleurocidin and dermaseptin (P-Der), and proline-arginine-rich peptide (PR-39). In addition, we also included the data of lactoferricin B (LfcinB) from our previous study for a more comprehensive analysis. We analyzed the unique protein hits of each AMP in the Kyoto Encyclopedia of Genes and Genomes. The results indicated that Bac7 targets purine metabolism and histidine kinase, LfcinB attacks the transcription-related activities and several cellular carbohydrate biosynthetic processes, P-Der affects several catabolic processes of small molecules, and PR-39 preferentially recognizes proteins involved in RNA- and folate-metabolism-related cellular processes. Moreover, both Bac7 and LfcinB target purine metabolism, whereas LfcinB and PR-39 target lipopolysaccharide biosynthesis. This suggested that LfcinB and Bac7 as well as LfcinB and PR-39 have a synergistic effect on antimicrobial activity, which was validated through antimicrobial assays. Furthermore, common hits of all four AMPs indicated that all of them target arginine decarboxylase, which is a crucial enzyme for Escherichia coli survival in extremely acidic environments. Thus, these AMPs may display greater inhibition to bacterial growth in extremely acidic environments. We have also confirmed this finding in bacterial growth inhibition assays. In conclusion, this comprehensive identification and systematic analysis of intracellular targeting AMPs reveals crucial insights into the intracellular mechanisms of the action of AMPs.

The proteome targets of intracellular targeting antimicrobial peptides.

Antimicrobial peptides have been considered well-deserving candidates to fight the battle against microorganisms due to their broad-spectrum antimicrobial activities. Several studies have suggested that membrane disruption is the basic mechanism of AMPs that leads to killing or inhibiting microorganisms. Also, AMPs have been reported to interact with macromolecules inside the microbial cells such as nucleic acids (DNA/RNA), protein synthesis, essential enzymes, membrane septum formation and cell wall synthesis. Proteins are associated with many intracellular mechanisms of cells, thus protein targets may be specifically involved in mechanisms of action of AMPs. AMPs like pyrrhocoricin, drosocin, apidecin and Bac 7 are documented to have protein targets, DnaK and GroEL. Moreover, the intracellular targeting AMPs are reported to influence more than one protein targets inside the cell, suggesting for the multiple modes of actions. This complex mechanism of intracellular targeting AMPs makes them more difficult for the development of resistance. Herein, we have summarized the current status of AMPs in terms of their mode of actions, entry to cytoplasm and inhibition of macromolecules. To reveal the mechanism of action, we have focused on AMPs with intracellular protein targets. We have also included the use of high-throughput proteome microarray to determine the unidentified AMP protein targets in this review.

BAPCP: A comprehensive and user-friendly web tool for identifying biomarkers from protein microarray technologies.

BACKGROUND AND OBJECTIVE: Proteome microarrays are one of the popular high-throughput screening methods for large-scale investigation of protein interactions in cells. These interactions can be measured on protein chips when coupled with fluorescence-labeled probes, helping indicate potential biomarkers or discover drugs. Several computational tools were developed to help analyze the protein chip results. However, existing tools fail to provide a user-friendly interface for biologists and present only one or two data analysis methods suitable for limited experimental designs, restricting the use cases. METHODS: In order to facilitate the biomarker examination using protein chips, we implemented a user-friendly and comprehensive web tool called BAPCP (Biomarker Analysis tool for Protein Chip Platforms) in this research to deal with diverse chip data distributions. RESULTS: BAPCP is well integrated with standard chip result files and includes 7 data normalization methods and 7 custom-designed quality control/differential analysis filters for biomarker extraction among experiment groups. Moreover, it can handle cost-efficient chip designs that repeat several blocks/samples within one single slide. Using experiments of the human coronavirus (HCoV) protein microarray and the E. coli proteome chip that helps study the immune response of Kawasaki disease as examples, we demonstrated that BAPCP can accelerate the time-consuming week-long manual biomarker identification process to merely 3 min. CONCLUSIONS: The developed BAPCP tool provides substantial analysis support for protein interaction studies and conforms to the necessity of expanding computer usage and exchanging information in bioscience and medicine. The web service of BAPCP is available at https://cosbi.ee.ncku.edu.tw/BAPCP/.

Reactions of Ru(III)-drugs KP1019 and KP418 with guanine, 2'-deoxyguanosine and guanosine: a DFT study.

Ruthenium (Ru)-based anticancer drugs are considered to be novel alternatives of platinum-based drugs. They exhibit potent cytotoxicity against the cancer cells and hence are useful for the treatment of cancer. Herein, the density functional theory calculations in the gas phase and aqueous media are carried out to study the reactions of two Ru(III)-based drugs such as KP1019 and KP418 with the N7 site of guanine (G), 2'-deoxyguanosine (dGua), and guanosine (Gua) to understand their reactivity against the DNA and RNA. All the reactions are found to be exothermic. The activation free energies and rate constants of these reactions indicate that KP1019 and KP418 would react with the dGua more readily than Gua. Hence, the binding of these drugs with the DNA would be more preferred as compared to RNA. It is further found that among these drugs, KP1019 would be more reactive than KP418 in agreement with the experimental observation. Thus, this study is expected to aid in the future development of potent anticancer drugs.

Suboptimal folic acid exposure rewires oncogenic metabolism and proteomics signatures to mediate human breast cancer malignancy.

Whether treatment with folic acid (FA) affects human breast cancer positively or negatively remains unclear. We subjected human Michigan Cancer Foundation-7 cells, a human breast cancer cell line, to suboptimal FA at low levels (10 nM; LF) and high levels (50 µM; HF) and investigated the molecular mechanisms underlying their effects through metabolic flux and systematic proteomics analyses. The data indicated that LF induced and HF aggravated 2-fold higher mitochondrial toxicity in terms of suppressed oxidative respiration, increased fermented glycolysis, and enhanced anchorage-independent oncospheroid formation. Quantitative proteomics and Gene Ontology enrichment analysis were used to profile LF- and HF-altered proteins involved in metabolism, apoptosis, and malignancy pathways. Through STRING analysis, we identified a connection network between LF- and HF-altered proteins with mammalian target of rapamycin (mTOR). Rapamycin-induced blockage of mTOR complex 1 (mTORC1) signaling, which regulates metabolism, differentially inhibited LF- and HF-modulated protein signatures of mitochondrial NADH dehydrogenase ubiquinone flavoprotein 2, mitochondrial glutathione peroxidase 4, kynureninase, and alpha-crystallin B chain as well as programmed cell death 5 in transcript levels; it subsequently diminished apoptosis and oncospheroid formation in LF/HF-exposed cells. Taken together, our data indicate that suboptimal FA treatment rewired oncogenic metabolism and mTORC1-mediated proteomics signatures to promote breast cancer development.

Synthesis of a Pyridone-Based Phthalimide Fleximer and Its Characterization and Supramolecular Property Evaluation.

In this study, a novel pyridone-based phthalimide fleximer, that is, ethyl 5-cyano-6-(3-(1,3-dioxoisoindolin-2-yl)propoxy)-4-(3-methoxyphenyl)-2-methylnicotinate, was synthesized, and its structure was established by the single-crystal X-ray diffraction method. The supramolecular self-assembly of the titled compound through noncovalent interactions was then investigated thoroughly. The titled compound crystallized with two symmetry-independent molecules (A and B, Z' = 2). In agreement with experimental observations, our density functional theory calculations also showed that the titled compound has a flexible motif and can occur in various conformations, including molecules A and B. The investigation of the supramolecular framework revealed that the molecules are notably bound by the nonclassical C-H···O and C-H···N hydrogen bonds and C-H···π interactions. Hirshfeld surface analysis was carried out to quantify the various intermolecular interactions. The dual anti-inflammatory activity of the tilted compound was also explored by molecular docking in the active sites of 5-LOX and COX-2 receptors, which revealed good binding affinities of -9.0 and -8.6 kcal/mol, respectively.

Probing Folate-Responsive and Stage-Sensitive Metabolomics and Transcriptional Co-Expression Network Markers to Predict Prognosis of Non-Small Cell Lung Cancer Patients.

Tumour metabolomics and transcriptomics co-expression network as related to biological folate alteration and cancer malignancy remains unexplored in human non-small cell lung cancers (NSCLC). To probe the diagnostic biomarkers, tumour and pair lung tissue samples (n = 56) from 97 NSCLC patients were profiled for ultra-performance liquid chromatography tandem mass spectrometry (UPLC/MS/MS)-analysed metabolomics, targeted transcriptionomics, and clinical folate traits. Weighted Gene Co-expression Network Analysis (WGCNA) was performed. Tumour lactate was identified as the top VIP marker to predict advance NSCLC (AUC = 0.765, Sig = 0.017, CI 0.58-0.95). Low folate (LF)-tumours vs. adjacent lungs displayed higher glycolytic index of lactate and glutamine-associated amino acids in enriched biological pathways of amino sugar and glutathione metabolism specific to advance NSCLCs. WGCNA classified the green module for hub serine-navigated glutamine metabolites inversely associated with tumour and RBC folate, which module metabolites co-expressed with a predominant up-regulation of LF-responsive metabolic genes in glucose transport (GLUT1), de no serine synthesis (PHGDH, PSPH, and PSAT1), folate cycle (SHMT1/2 and PCFR), and down-regulation in glutaminolysis (SLC1A5, SLC7A5, GLS, and GLUD1). The LF-responsive WGCNA markers predicted poor survival rates in lung cancer patients, which could aid in optimizing folate intervention for better prognosis of NSCLCs susceptible to folate malnutrition.

Green synthesis, structural analysis and anticancer activity of dihydropyrimidinone derivatives.

In this study, for the first time, we have used Citrus macroptera juice to synthesize dihydropyrimidine (DHPM) derivatives via the Biginelli reaction, which showed better yield, shorter reaction time, and did not require an organic solvent for the reaction. A series of DHPM derivatives were synthesized, and characterized, and structural analysis was achieved through SCXRD & Hirshfeld surface analysis. We observed that these synthesized dihydropyrimidine (DHPM) derivatives showed C-H⋯π, C-H⋯O, C-H⋯N, C-H⋯C, lone pair⋯π, π⋯π, etc. interactions. We also performed in silico studies for their inhibitory activities against human kinesin Eg5 enzyme, and the cytotoxic activity of the synthesized compounds was carried out against A549 lung adenocarcinoma cells. In silico analysis demonstrated that compounds with a chloro-group at the 3- or 4-position in the substituted ring of DHPM showed higher binding affinity for the human kinesin Eg5 enzyme (-7.9 kcal mol-1) than the standard drug monastrol (-7.8 kcal mol-1). Furthermore, in vitro cellular studies revealed that compounds with a chloro-group at the 3- or 4-position in the substituted ring of DHPM induced significant cell death in human A549 lung adenocarcinoma cells. This result indicates that a deactivating group (chlorine) at the 3- or 4-position in the substituted ring of DHPM might be a promising anticancer drug candidate for treating different types of cancers, particularly cancer of the lung.

Calculated parenteral initial therapy of bacterial infections: Bacterial meningitis.

This is the thirteenth chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. Bacterial meningitis is a life-threatening infectious disease with high mortality and disability rates requiring prompt initiation of antimicrobial treatment to lower these rates.

Calculated initial parenteral treatment of bacterial infections: Bacterial endocarditis.

This is the twelfth chapter of the guideline "Calculated initial parenteral treatment of bacterial infections in adults - update 2018" in the 2nd updated version. The German guideline by the Paul-Ehrlich-Gesellschaft für Chemotherapie e.V. (PEG) has been translated to address an international audience. The bacterial endocarditis is characterised by a constant incidence but a shift in the patient population due to the use of prosthetic heart valves and foreign materials like pacemakers and the increasing application of invasive medical procedures. This is linked to a change in the predominant infecting organisms towards staphylococci. This chapter gives recommendations for the interdisciplinary management of infective endocarditis from the diagnostic workup over prevention to therapy with a focus on antibiotic therapy.

Concentrations of piperacillin-tazobactam in human jaw and hip bone.

OBJECTIVES: It is unclear to what extent pharmacokinetic data from bone outside the facial area can be transferred to the maxillofacial area. The aim of this study was to evaluate the penetration characteristics of piperacillin-tazobactam into human jaw and hip bone as a model for different bone characteristics. MATERIALS AND METHODS: The drug was administered at the start of surgery in a single 15-min intravenous infusion dose (4g piperacillin & 0.5g tazobactam i.v.). Plasma and bone samples of ten patients were analyzed. RESULTS: Mean concentration of piperacillin in plasma was 309microg/ml at 0.5h declining at 4h to 14microg/ml. The respective values for tazobactam were 34microg/ml declining to 2.8microg/ml. The piperacillin-tazobactam ratio dropped during the study interval from 0.5h: 9.2%+/-0.8 to 2h: 7.2%+/-1.1 and 4h: 4.9%+/-0.7. Mean bone concentrations of piperacillin and tazobactam were 9.0+/-11.6microg/g and 1.2+/-1.3microg/g, respectively. Mean penetration ratios for all bone samples were 15% (+/-17) for piperacillin and 13% (+/-14) for tazobactam without a difference between bone of different origin. DISCUSSION: Piperacillin-tazobactam levels in jaw bone tissue after a single dose are sufficient to assure antibacterial activity of the combination and are above the minimal inhibitory concentrations of the most relevant pathogens in head and neck surgery. Our data suggests the use of piperacillin-tazobactam as an alternative for the therapy of severe infections of the head and neck.

[No obvious difference in Streptococcus pneumoniae antibiotic resistance profiles--isolates from HIV-positive and HIV-negative patients]. / Vergleichbare Antibiotikaresistenz von Pneumokokkenisolaten HIV-positiver und -negativer Patienten.

BACKGROUND AND PURPOSE: HIV patients are overexposed to hospital environment, immune suppression, and antibiotic prophylaxes. Therefore, with HIV positive patients an increased risk for resistant bacterial rods is to be expected. The purpose of this case-control study was to determine the susceptibility patterns of pneumococci from adult patients in relation to their HIV status and to compare both patient groups. PATIENTS AND METHODS: Between January 2001 and December 2005, samples from internal medicine patients of one university hospital laboratory were investigated on culture of Streptococcus pneumoniae and in case of a positive vial, a resistance test was done by agar diffusion method. All patients with culture-confirmed infection due to pneumococci underwent a standardized retrospective evaluation in regard to demographic and clinical characteristics including HIV status. RESULTS: A total amount of 135 Streptococcus pneumoniae cultures could be assigned to 64 HIV-positive (A) and 71 HIV-negative patients (B), with susceptibility results for 134 isolates. Full susceptibility was seen in 44 (69.8% [A]) versus 42 (59.2% [B]) samples, reduced susceptibility ("intermediate-susceptible") was found in eight (12.7% [A]) versus 17 (23.9% [B]). Eleven (17.5% [A]) and twelve (16.9% [B]), respectively, out of all pneumococci were tested resistant to at least one antibiotic. Among these, resistance to erythromycin was most relevant (11.1% [A] and 11.3% [B]). None of the tested rods was resistant to penicillin. All differences between groups for susceptibility testing were not found significant. HIV-negative patients were significantly older, needed more often hospitalization and intensive care, and cultures for pneumococci were more frequently positive in primary sterile materials, such as cerebrospinal fluid and blood. The difference concerning death within 28 days following positive sample was just not significant as well as in immune suppression status of patients. HIV patients experienced more frequently an infection relapse and were more frequently smokers. CONCLUSION: No obvious difference in pneumococci resistance patterns was observed between HIV-positive and HIV-negative adult patients. The absence of resistance to penicillin underscores the importance of beta-lactams in case of typical community-acquired pneumonia; therefore, this class of antibiotics should be included in treatment guidelines as first-line drugs also for HIV patients. HIV-negative controls of this study were more aged and suffered from a higher morbidity, however, the fact that they were not significantly less immune suppressed may be special character of a university hospital control patient group. HIV patients presented in an earlier stage of their pneumococcal disease, probably due to a direct access to tertiary hospital medical supply. A higher relapse rate underscores the importance of pneumococcal vaccination for HIV patients.

A replaceable liposomal aptamer for the ultrasensitive and rapid detection of biotin.

Biotin is an essential vitamin which plays an important role for maintaining normal physiological function. A rapid, sensitive, and simple method is necessary to monitor the biotin level. Here, we reported a replacement assay for the detection of biotin using a replaceable liposomal aptamer. Replacement assay is a competitive assay where a sample analyte replaces the labeled competitor of analyte out of its biorecognition element on a surface. It is user friendly and time-saving because of washing free. We used aptamer as a competitor, not a biorecognition element as tradition. To label aptamers, we used cholesterol-conjugated aptamers to tag signal-amplifying-liposomes. Without the need of conjugation procedure, aptamers can be easily incorporated into the surface of dye-encapsulating liposomes. Two aptamers as competitors of biotin, ST-21 and ST-21M with different affinities to streptavidin, were studied in parallel for the detection of biotin using replacement assays. ST-21 and ST-21M aptamers reached to limits of detection of 1.32 pg/80 µl and 0.47 pg/80 µl, respectively. The dynamic ranges of our assays using ST-21 and ST-21M aptamers were seven and four orders of magnitude, respectively. This assay can be completed in 20 minutes without washing steps. These results were overall better than previous reported assays.