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b lactamics

E Espigares, E Moreno Roldan, M Espigares, R Abreu, B Castro, A L Dib, Á Arias
The aim of this research was to study the phenotypic resistances to disinfectants and antibiotics in strains of methicillin-resistant Staphylococcus aureus (MRSA) obtained from Canary black pigs. Analyses were performed on 54 strains of MRSA, isolated in Canary black pigs from the province of Tenerife (Spain); all of them carried the mecA gene. The strains were isolated by means of nasal swab samples of healthy pigs, collected under veterinarian supervision. Bactericidal activity of antiseptics and disinfectants was tested by means of the dilution-neutralization method...
October 20, 2016: Zoonoses and Public Health
Scott A Shuler, Guoyin Yin, Sarah B Krause, Caroline M Vesper, Donald A Watson
The preparation of unsaturated secondary lactams via the palladium-catalyzed cyclization of O-phenyl hydroxamates onto a pendent alkene is reported. This method provides rapid access to a broad range of lactams that are widely useful building blocks in alkaloid synthesis. Mechanistic studies support an aza-Heck-type pathway.
October 18, 2016: Journal of the American Chemical Society
L Brulikova, Y Okorochenkova, J Hlavac
An efficient methodology using the Fukuyama-Mitsunobu reaction was successfully applied to prepare various Rhodamine B-based amides with the locked possibility to form a lactam ring. The procedure was developed for solid-phase synthesis, which can be advantageously applied to the synthesis of chemical libraries in a combinatorial fashion. A series of derivatives including aliphatic as well as aromatic rhodamine amides alkylated via a reaction with various alcohols were synthesized, and their spectral properties were investigated...
October 18, 2016: Organic & Biomolecular Chemistry
Claudia Weilbeer, Marcel Sickert, Sergej Naumov, Christoph Schneider
We disclose herein the first enantioselective aza-Diels-Alder reaction of b-alkyl-substituted vinylketene silyl-O,O-acetals and imines furnishing a broad range of optically highly enriched 4-alkyl-substituted 2-piperidones. As catalyst for this one-pot reaction we employed a chiral phosphoric acid which effects a vinylogous Mannich reaction directly followed by ring-closure to the lactam. Subsequent fully diastereoselective transformations including hydrogenation, enolate alkylation, and lactam alkylation/reduction processes converted the cycloadducts into various highly substituted piperidines of great utility for the synthesis of natural products and medicinally active compounds...
October 17, 2016: Chemistry: a European Journal
John Chu, Xavier Vila-Farres, Daigo Inoyama, Melinda Ternei, Louis J Cohen, Emma A Gordon, Boojala Vijay B Reddy, Zachary Charlop-Powers, Henry A Zebroski, Ricardo Gallardo-Macias, Mark Jaskowski, Shruthi Satish, Steven Park, David S Perlin, Joel S Freundlich, Sean F Brady
Here we present a natural product discovery approach, whereby structures are bioinformatically predicted from primary sequence and produced by chemical synthesis (synthetic-bioinformatic natural products, syn-BNPs), circumventing the need for bacterial culture and gene expression. When we applied the approach to nonribosomal peptide synthetase gene clusters from human-associated bacteria, we identified the humimycins. These antibiotics inhibit lipid II flippase and potentiate β-lactam activity against methicillin-resistant Staphylococcus aureus in mice, potentially providing a new treatment regimen...
October 17, 2016: Nature Chemical Biology
Pauline M Lang, Rogério C Jacinto, Tatiane S Dal Pizzol, Maria Beatriz C Ferreira, Francisco Montagner
Infected root canal or acute apical abscess exudates can harbour several species, including Fusobacterium, Porphyromonas, Prevotella, Parvimonas, Streptococcus, Treponema, Olsenella and not-yet cultivable species. A systematic review and meta-analysis was performed to assess resistance rates to antimicrobial agents in clinical studies that isolated bacteria from acute endodontic infections. Electronic databases and the grey literature were searched up to May 2015. Clinical studies in humans evaluating the antimicrobial resistance of primary acute endodontic infection isolates were included...
September 30, 2016: International Journal of Antimicrobial Agents
A A Al-Gheethi, R M S R Mohamed, A N Efaq, I Norli, Abdullah Abd Halid, H K Amir, M O Ab Kadir
The study probed into reducing faecal indicators and pathogenic bacteria, heavy metals and β-lactam antibiotics, from four types of secondary effluents by bioaugmentation process, which was conducted with Bacillus subtilis strain at 45 °C. As a result, faecal indicators and pathogenic bacteria were reduced due to the effect of thermal treatment process (45 °C), while the removal of heavy metals and β-lactam antibiotics was performed through the functions of bioaccumulation and biodegradation processes of B...
October 2016: Journal of Water and Health
David A Khan
Adverse drug reactions (ADRs) are a relatively common cause of morbidity and mortality. Many factors can contribute to ADRs, including genetics. The degree to which genetics contributes to ADRs is not entirely clear and varies by drug, as well as the type of ADR. Pharmacogenetics and, more recently, pharmacogenomics have been applied to the field of ADRs for both predictable ADRs and hypersensitivity drug reactions. Evaluations for glucose-6-phosphate dehydrogenase and thiopurine S-methyltransferase are commonplace clinical tests to reduce hematologic problems associated with drugs, such as dapsone and azathioprine, respectively...
October 2016: Journal of Allergy and Clinical Immunology
Mazen S Bader, Mark Loeb, Annie A Brooks
Urinary tract infections (UTIs) caused by antibiotic-resistant Gram-negative bacteria are a growing concern due to limited therapeutic options. Gram-negative bacteria, specifically Enterobacteriaceae, are common causes of both community-acquired and hospital acquired UTIs. These organisms can acquire genes that encode for multiple antibiotic resistance mechanisms, including extended-spectrum-lactamases (ESBLs), AmpC- β -lactamase, and carbapenemases. The assessment of suspected UTI includes identification of characteristic symptoms or signs, urinalysis, dipstick or microscopic tests, and urine culture if indicated...
October 7, 2016: Postgraduate Medicine
Velma Rebic, Ana Budimir, Mufida Aljicevic, Sabaheta Bektas, Sabina Mahmutovic Vranic, Damir Rebic
BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is responsible for a wide spectrum of nosocomial and community associated infections worldwide. The aim of this study was to analyze MRSA strains from the general population in Canton Sarajevo, B&H. METHODS: Our investigation including either phenotypic and genotypic markers such as antimicrobial resistance, pulsed-field gel electrophoresis (PFGE), SCC typing, and Panton-Valentine leukocidin (PVL) detection...
July 16, 2016: Acta Informatica Medica: AIM
M Bochniarz, Ł Adaszek, B Dzięgiel, A Nowaczek, W Wawron, R Dąbrowski, M Szczubiał, S Winiarczyk
The aim of this study was to recognize selected factors of virulence determining the adhesion of Staphylococcus chromogenes to cows' udder tissues in subclinical mastitis and to evaluate the susceptibility of this pathogen to antibiotics. The subjects of the study were 38 isolates of Staph. chromogenes from 335 samples of milk from cows with subclinical coagulase-negative staphylococci mastitis. Somatic cell count ranged between 216,000 and 568,000/mL of milk (average 356,000/mL of milk). We confirmed the ability to produce slime in 24 isolates (63...
September 28, 2016: Journal of Dairy Science
Arun Tailor, James C Waddington, Xiaoli Meng, B Kevin Park
The covalent binding of drugs (metabolites) to proteins to form drug-protein adducts can have an adverse effect on the body. These adducts are thought to be responsible for idiosyncratic drug reactions including severe drug hypersensitivity reactions. Major advances in proteomics technology have allowed for the identification and quantification of target proteins for certain drugs. Human serum albumin (HSA) and Hb have been identified as accessible targets and potential biomarkers for drug-protein adducts formation, for numerous drugs (metabolites) including β-lactam antibiotics, reactive drug metabolites such as quinone imines (acetaminophen) and acyl glucuronides (diclofenac), and covalent inhibitors (neratinib)...
September 30, 2016: Chemical Research in Toxicology
Modesto de Candia, Giorgia Zaetta, Nunzio Denora, Domenico Tricarico, Maria Majellaro, Saverio Cellamare, Cosimo D Altomare
Several 6-substituted 3,4,5,6-tetrahydroazepino[4,3-b]indol-1(2H)-one (THAI) derivatives were synthesized and evaluated for their activity as cholinesterase (ChE) inhibitors. The most potent inhibitors were identified among 6-(2-phenylethyl)-THAI derivatives, and in particular compounds 12b and 12d proved to be very active against human BChE (IC50 = 13 and 1.8 nM, respectively), with 1000-fold selectivity over AChE. Structure-activity relationships highlighted critical features (e.g., ring fusion [4,3-b], integrity of the lactam CONH function) and favorable physicochemical properties of the 6-(2-phenylethyl) group (i...
September 13, 2016: European Journal of Medicinal Chemistry
Shanshan Zhou, Lona M Alkhalaf, Emmanuel Lc de Los Santos, Gregory L Challis
Class B radical S-adenosylmethionine (SAM) methylases are notable for their ability to catalyse methylation reactions in the biosynthesis of a wide variety of natural products, including polyketides, ribosomally biosynthesised and post-translationally modified peptides (RiPPs), nonribosomal peptides (NRPs), aminoglycosides, β-lactams, phosphonates, enediynes, aminocoumarins and terpenes. Here, we discuss the diversity of substrates and catalytic mechanism utilised by such enzymes, highlighting the stereochemical course of methylation reactions at un-activated carbon centres and the ability of some members of the family to catalyse multiple methylations...
September 12, 2016: Current Opinion in Chemical Biology
Shannon B Falconer, Sarah A Reid-Yu, Andrew M King, Sebastian S Gehrke, Wenliang Wang, James F Britten, Brian K Coombes, Gerard D Wright, Eric D Brown
The widespread emergence of antibiotic drug resistance has resulted in a worldwide healthcare crisis. In particular, the extensive use of β-lactams, a highly effective class of antibiotics, has been a driver for pervasive β-lactam resistance. Among the most important resistance determinants are the metallo-β-lactamases (MBL), which are zinc-requiring enzymes that inactivate nearly all classes of β-lactams, including the last-resort carbapenem antibiotics. The urgent need for new compounds targeting MBL resistance mechanisms has been widely acknowledged; however, the development of certain types of compounds-namely metal chelators-is actively avoided due to host toxicity concerns...
November 13, 2015: ACS Infectious Diseases
Katherine A Rhodes, Herbert P Schweizer
The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients...
September 2016: Drug Resistance Updates: Reviews and Commentaries in Antimicrobial and Anticancer Chemotherapy
Clyde A Smith, Zahra Nossoni, Marta Toth, Nichole K Stewart, Hilary Frase, Sergei B Vakulenko
Some members of the class A β-lactamase family are capable of conferring resistance to the last resort antibiotics, carbapenems. A unique structural feature of these clinically important enzymes, collectively referred to as class A carbapenemases, is a disulfide bridge between invariant Cys(69) and Cys(238) residues. It was proposed that this conserved disulfide bridge is responsible for their carbapenemase activity, but this has not yet been validated. Here we show that disruption of the disulfide bridge in the GES-5 carbapenemase by the C69G substitution results in only minor decreases in the conferred levels of resistance to the carbapenem imipenem and other β-lactams...
October 14, 2016: Journal of Biological Chemistry
George Sakoulas, Joshua Olson, Juwon Yim, Niedita B Singh, Monika Kumaraswamy, Diana T Quach, Michael J Rybak, Joseph Pogliano, Victor Nizet
BACKGROUND: Ertapenem and cefazolin were used in combination to successfully clear refractory methicillin-susceptible Staphylcoccus aureus (MSSA) bacteremia. In addition, recent work has demonstrated acitivity of combination beta-lactam therapy from different classes against MRSA. METHODS: Ertapenem plus cefazolin combination was evaluated for synergy in vitro and in vivo in a murine skin infection model using an index MSSA bloodstream isolate from a patient in whom persistent bacteremia was cleared with this combination, and against a cadre of well-described research strains and clinical strains of MSSA and MRSA...
August 29, 2016: Antimicrobial Agents and Chemotherapy
M Alonso-Isa, J Medina-Polo, A Lara-Isla, S Pérez-Cadavid, A Arrébola-Pajares, R Sopeña-Sutil, R Benítez-Sala, J Justo-Quintas, J Gil-Moradillo, J B Passas-Martínez, A Tejido-Sánchez
OBJECTIVES: Open surgery continues to have a fundamental role in urology, and one of its main complications is surgical wound infection. Our objective was to analyse surgical wound infection in patients who underwent surgery in our Department of Urology and to assess the risk factors, microorganisms and resistances by type of surgery. MATERIAL AND METHODS: This was a prospective observational study that included 940 patients: 370 abdominal/open lumbar surgeries and 570 genitoperineal surgeries...
August 23, 2016: Actas Urologicas Españolas
Nazim Hasan, Zhongxian Guo, Hui-Fen Wu
Bacteria or their protein and peptide entity enrichment using biomolecules-functionalized magnetic nanoparticles, and analysis by matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) is a promising technique to analyze microorganisms. High and low molecular weight proteins like penicillin-binding proteins are responsible for final step synthesis of peptidoglycan biosynthesis; those are the target of lactam antibiotics. In this paper, we synthesized magnetic nanoparticles (mag-NPs) and further modified them with 3-aminopropyltriethoxysilane, and then the β-lactam antibiotic amoxicillin was covalently linked to their surface...
September 2016: Analytical and Bioanalytical Chemistry
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