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https://www.readbyqxmd.com/read/29317513/cyclic-amp-regulates-bacterial-persistence-through-repression-of-the-oxidative-stress-response-and-sos-dependent-dna-repair-in-uropathogenic-escherichia-coli
#1
Roberto C Molina-Quiroz, Cecilia Silva-Valenzuela, Jennifer Brewster, Eduardo Castro-Nallar, Stuart B Levy, Andrew Camilli
Bacterial persistence is a transient, nonheritable physiological state that provides tolerance to bactericidal antibiotics. The stringent response, toxin-antitoxin modules, and stochastic processes, among other mechanisms, play roles in this phenomenon. How persistence is regulated is relatively ill defined. Here we show that cyclic AMP, a global regulator of carbon catabolism and other core processes, is a negative regulator of bacterial persistence in uropathogenic Escherichia coli, as measured by survival after exposure to a β-lactam antibiotic...
January 9, 2018: MBio
https://www.readbyqxmd.com/read/29310494/effectiveness-of-vancomycin-or-beta-lactam-therapy-in-ampicillin-susceptible-enterococcus-spp-bloodstream-infections
#2
Jesse M Fletcher, Shawn J Kram, Christina B Sarubbi, Deverick J Anderson, Bridgette L Kram
BACKGROUND: De-escalation to a beta-lactam improves outcomes for patients with a methicillin-susceptible Staphylococcus aureus bloodstream infection (BSI). Whether a similar strategy is appropriate for enterococcal species is less clear. OBJECTIVE: To determine whether definitive antibiotic selection affects outcomes for patients with an ampicillin-susceptible enterococcal BSI. METHODS: This retrospective cohort study included patients over 18 years of age receiving definitive therapy with vancomycin or a beta-lactam for one or more blood cultures positive for Enterococcus spp...
January 1, 2018: Journal of Pharmacy Practice
https://www.readbyqxmd.com/read/29306206/design-synthesis-biological-evaluation-and-cocrystal-structures-with-tubulin-of-chiral-%C3%AE-lactam-bridged-combretastatin-a-4-analogues-as-potent-antitumor-agents
#3
Pengfei Zhou, Yuru Liang, Hao Zhang, Hao Jiang, Kechang Feng, Pan Xu, Jie Wang, Xiaoming Wang, Kuiling Ding, Cheng Luo, Mingming Liu, Yang Wang
A diverse of chiral β-lactam bridged analogues of combretastatin A-4 (CA-4), 3-substituted 1,4-diaryl-2-azetidinones, were asymmetrically synthesized and biologically evaluated, leading to identify a number of potent anti-proliferative compounds represented by 14b and 14c with IC50 values of 0.001-0.021 μM, against four human cancer cell lines (A2780, Hela, SKOV-3 and MDA-MB-231). Structure-activity relationship (SAR) studies on all stereoisomers of 14b and 14c revealed that the absolute configurations of the chiral centers at 3- and 4-position were critically important for the activity and generally a trans configuration between the "A" and "B" rings is optimal...
December 7, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/29277334/neurological-disease-may-precede-lymphadenopathies-in-actinomyces-europaeus-infection
#4
Silvia Corcione, Antonio Curtoni, Ivana A Paolucci, Giovanni Di Perri, Francesco G De Rosa, Rossana Cavallo
Actinomyces species are part of the commensal flora of the mucous membranes of the oropharynx, gastrointestinal tract and female genital tract. Actinomyces europaeus is a short, nonmotile, facultative anaerobic rod first described in 1997, susceptible in vitro to a wide range of b-lactam antibiotics which are regarded as first choice. In this report we described the case of A. europaeus infection in a young female patient admitted to Intensive Care Unit and the possible damage of vascular endothelium due to a chronic progressive actinomycosis that at first involved neck soft tissue, then cervical lymphnodes, and finally extended to the vascular structure...
December 22, 2017: Journal of Infection and Public Health
https://www.readbyqxmd.com/read/29240031/thoracic-actinomycosis-with-infiltration-of-the-spine-an-oncological-pitfall
#5
Leila Ronceray, Waltraud Friesenbichler, Caroline Hutter, Karoly Lakatos, Wolfgang Krizmanich, Gabriele Amann, Kaan Boztug, Leo Kager, Georg Mann, Andishe Attarbaschi
Thoracic actinomycosis with involvement of the vertebral column and chest wall is rare in children and may resemble malignant tumors. A 12-year-old girl was admitted to our clinic having B-symptoms, cachexia, and painful scoliosis (Karnofsky index 20%). Imaging showed a large thoracic left-sided paravertebral tumor with infiltration of the vertebrae, destruction of the chest wall and multiple intrapulmonary nodules. Initially, Ewing sarcoma was suspected and chemotherapy started without previous biopsies. Definite diagnosis of actinomycosis was established later upon histopathologic examination and successfully treated by β-lactam antibiotics...
December 12, 2017: Journal of Pediatric Hematology/oncology
https://www.readbyqxmd.com/read/29236036/efficient-enzymatic-routes-for-the-synthesis-of-new-eight-membered-cyclic-%C3%AE-amino-acid-and-%C3%AE-lactam-enantiomers
#6
Enikő Forró, Loránd Kiss, Judit Árva, Ferenc Fülöp
Efficient enzymatic resolutions are reported for the preparation of new eight-membered ring-fused enantiomeric β-amino acids [(1R,2S)-9 and (1S,2R)-9] and β-lactams [(1S,8R)-3, (1R,8S)-3 (1S,8R)-4 and (1R,8S)-7], through asymmetric acylation of (±)-4 (E > 100) or enantioselective hydrolysis (E > 200) of the corresponding inactivated (±)-3 or activated (±)-4 β-lactams, catalyzed by PSIM or CAL-B in an organic solvent. CAL-B-catalyzed ring cleavage of (±)-6 (E > 200) resulted in the unreacted (1S,8R)-6, potential intermediate for the synthesis of enantiomeric anatoxin-a...
December 13, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29224710/spm-1-producing-pseudomonas-aeruginosa-st277-clone-recovered-from-microbiota-of-migratory-birds
#7
Willames M B S Martins, Ana Clara Narciso, Rodrigo Cayô, Stéfanie Vanessa Santos, Lorena C C Fehlberg, Patrícia Locosque Ramos, João Batista da Cruz, Ana Cristina Gales
The production of São Paulo metallo-β-lactamase (SPM-1) is the most common carbapenem resistance mechanism detected among multidrug-resistant Pseudomonas aeruginosa clinical isolates in Brazil. Dissemination of SPM-1-producing P. aeruginosa has been restricted to the nosocomial settings, with sporadic reports of environmental isolates due to contamination by hospital sewage. Herein, we described the detection and molecular characterization of SPM-1-producing P. aeruginosa recovered from the microbiota of migratory birds in Brazil...
November 10, 2017: Diagnostic Microbiology and Infectious Disease
https://www.readbyqxmd.com/read/29219109/antimicrobial-resistance-in-corynebacterium-spp-arcanobacterium-spp-and-trueperella-pyogenes
#8
Andrea T Feßler, Stefan Schwarz
There is currently only limited information on the antimicrobial susceptibility and resistance of Corynebacterium spp., Arcanobacterium spp., and Trueperella pyogenes from animals. The comparability of the data is hampered by the use of different antimicrobial susceptibility testing methods and interpretive criteria. To date, standard broth microdilution methods and clinical breakpoints that are approved by the Clinical and Laboratory Standards Institute and are applicable to Corynebacterium spp., Arcanobacterium spp...
December 2017: Microbiology Spectrum
https://www.readbyqxmd.com/read/29215585/xanthones-and-quinolones-derivatives-produced-by-the-deep-sea-derived-fungus-penicillium-sp-scsio-ind16f01
#9
Feng-An Liu, Xiuping Lin, Xuefeng Zhou, Minghao Chen, Xiuling Huang, Bin Yang, Huaming Tao
Chemical investigation of the fungus Penicillium sp. SCSIO Ind16F01 derived from deep-sea sediment sample afforded a new xanthone, 3,8-dihydroxy-2-methyl-9-oxoxanthene-4-carboxylic acid methyl ester (1) and a new chromone, coniochaetone J (2), together with three known xanthones, 8-hydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (3), 7,8-dihydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylic acid methyl ester (4), 1,6,8-trihydroxy-3-(hydroxymethyl)anthraquinone (5), three known chromones, coniochaetone B (6), citrinolactones B (7), epiremisporine B (8), and four reported rare class of N-methyl quinolone lactams: quinolactacins B (9), C1 (10), and C2 (11), and quinolonimide (12)...
December 7, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29199418/-cefditoren-a-reality-for-the-treatment-of-community-infections
#10
REVIEW
B Sánchez Artola, J Barberán
Cefditoren, a third-generation cephalosporin, is the oral β-lactam more active against the main community-acquired respiratory tract pathogens (including resistance phenotypes such as penicillin-resistant Streptococcus pneumoniae and ampicillin-resistant Haemophilus influenzae), similar to cefotaxime. Data obtained from clinical trials and later evidence on efficacy and safety, support that cefditoren is an suitable option for the treatment of mild-to moderate community respiratory and urinary tract infections, particularly in regions where non-susceptible phenotipes to common oral antibiotics are prevalent...
December 4, 2017: Revista Española de Quimioterapia: Publicación Oficial de la Sociedad Española de Quimioterapia
https://www.readbyqxmd.com/read/29198902/inoculum-effect-of-high-concentrations-of-methicillin-susceptible-staphylococcus-aureus-on-the-efficacy-of-cefazolin-and-other-beta-lactams
#11
Masachika Saeki, Masaaki Shinagawa, Yuki Yakuwa, Shinya Nirasawa, Yuki Sato, Nozomi Yanagihara, Satoshi Takahashi
The existence of a cefazolin inoculum effect (InE) of methicillin-susceptible Staphylococcus aureus (MSSA), which is speculated to be a reason for cefazolin treatment failure in MSSA infections, is controversial. In Japan, although cefazolin is one of the therapeutic choices for patients with MSSA infection, there are few reports of this effect. Additionally, the association between InE and blaZ type in beta-lactams other than cefazolin has not been well documented. In this study, we confirmed an MSSA InE in several beta-lactams, including cefazolin, and its relationship with blaZ, using 52 MSSA isolates from blood cultures...
November 30, 2017: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
https://www.readbyqxmd.com/read/29156265/occurrence-and-fate-of-most-prescribed-antibiotics-in-different-water-environments-of-tehran-iran
#12
Roya Mirzaei, Masud Yunesian, Simin Nasseri, Mitra Gholami, Esfandiyar Jalilzadeh, Shahram Shoeibi, Alireza Mesdaghinia
The presence of most prescribed antibiotic compounds from four therapeutic classes (β-lactam, cephalosporins, macrolides, fluoroquinolones) were studied at two full-scale WWTPs, two rivers, thirteen groundwater resources, and five water treatment plants in Tehran. Analytical methodology was based on high performance liquid chromatography/tandem mass spectrometry after solid-phase extraction. Samples were collected at 33 sample locations on three sampling periods over four months from June to August 2016. None of the target antibiotics were detected in groundwater resources and water treatment plants, while seven out of nine target antibiotics were analyzed in two studied river waters as well as the influent and effluent of wastewater treatment plants at concentrations ranging from <LOQ to 926...
November 16, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29148816/assessment-of-anti-piperacillin-igg-binding-to-structurally-related-drug-protein-adducts
#13
Mohammed Amali, Rosalind Jenkins, Xioali Meng, Lee Faulkner, Paul Whitaker, Daniel Peckham, B Kevin Park, Dean John Naisbitt
The risk of developing hypersensitivity to alternative antibiotics is a concern for penicillin hypersensitive patients and healthcare pro-viders. Herein we use piperacillin hypersensitivity as a model to explore the reactivity of drug-specific IgG against alternative β-lactam protein adducts. Mass spectrometry was used to show the drugs (amoxicillin, flucloxacillin, benzyl penicillin, aztreonam and pipera-cillin) bind to similar lysine residues on the protein carrier bovine serum albumin. However, the hapten-specific IgG antibodies found in piperacillin hypersensitive patient plasma did not bind to other β-lactam protein conjugates...
November 17, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/29146833/draft-genome-sequences-of-eight-streptogramin-resistant-enterococcus-species-isolated-from-animal-and-environmental-sources-in-the-united-states
#14
Poonam Sharma, Sushim Kumar Gupta, John B Barrett, Lari M Hiott, Sandra L House, Tiffanie A Woodley, Jonathan G Frye, Charlene R Jackson
Here, we present the draft genome sequences of eight streptogramin-resistant Enterococcus species isolated from animals and an environmental source in the United States from 2001 to 2004. Antimicrobial resistance genes were identified conferring resistance to the macrolide-lincosamide-streptogramins, aminoglycosides, tetracyclines, beta-lactams, and glycopeptides.
November 16, 2017: Genome Announcements
https://www.readbyqxmd.com/read/29144958/isolation-of-blandm-producing-enterobacteriaceae-in-a-public-hospital-in-salvador-bahia-brazil
#15
Maria Goreth Barberino, Silvia de Araujo Cruvinel, Célio Faria, Marco Aurélio Salvino, Márcio Oliveira
Carbapenemases have great importance in the global epidemiological scenario since infections with carbapenemase-producing bacteria are associated with high mortality, especially in hospitalized patients in intensive care units. This study describes two microorganisms producers of the New Delhi Metallo-b-lactamase (NDM), Klebsiella pneumoniae and Citrobacter freundii, from two patients admitted to a public hospital in Salvador, Bahia. These are the first clinical cases of NDM described in microorganisms in the north and northeast Brazil...
November 13, 2017: Brazilian Journal of Infectious Diseases
https://www.readbyqxmd.com/read/29135242/computational-study-on-%C3%AE-c-h-functionalization-of-%C3%AE-%C3%AE-unsaturated-ester-catalyzed-by-n-heterocyclic-carbene-mechanisms-origin-of-stereoselectivity-and-role-of-catalyst
#16
Yang Wang, Donghui Wei, Mingsheng Tang
The N-heterocyclic carbene (NHC)-catalyzed γ-C-H deprotonation/functionalization of α,β-unsaturated esters with hydrazones leading to the δ-lactams has been theoretically investigated by using density functional theory. Three possible reaction mechanisms including Mechanism A, for which the NHC catalyst serves as a nucleophilic catalyst to attack on the carbonyl carbon atom to initiate the reaction, Mechanism B, in which NHC triggers the reaction through the hydrogen bond, and Mechanism C, which is the direct deprotonation/functionalization process without the presence of NHC, have been suggested and studied in detail...
November 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/29120635/total-synthesis-of-himalensine-a
#17
Heyao Shi, Iacovos N Michaelides, Benjamin Darses, Pavol Jakubec, Quynh Nhu N Nguyen, Robert S Paton, Darren J Dixon
The first enantioselective synthesis of (-)-himalensine A has been achieved in 22 steps. The synthesis was enabled by a novel catalytic, enantioselective prototropic shift / furan Diels-Alder (IMDAF) cascade to construct the ACD tricyclic core. A reductive radical cyclization cascade was utilized to build the B ring, and end game manipulations featuring a molecular oxygen mediated γ-CH oxidation, a Stetter cyclization to access the pendant cyclopentenone and a highly chemoselective lactam reduction delivered the natural product target...
November 9, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29107079/clonal-spread-of-carbapenem-resistant-acinetobacter-baumannii-in-neonatal-intensive-care-unit
#18
Wirlaine Glauce Maciel, Kesia Esther da Silva, Julio Croda, Rodrigo Cayô, Ana Carolina Ramos, Romário Oliveira de Sales, Gleyce Hellen de Almeida de Souza, José Victor Bortolotto Bampi, Leticia Cristina Limiere, Junior César Casagrande, Ana Cristina Gales, Simone Simionatto
Acinetobacter baumannii has been frequently associated with colonization and/or infection in neonatal intensive care units (NICU). In this study, we describe a clonal spread of carbapenem-resistant A. baumannii (CRAB) isolates in a NICU. A total of 21 CRAB isolates were collected from premature newborns. Only polymyxin B was active against such isolates. Nineteen CRAB isolates were clonally related (cluster C that belonged to worldwide-disseminated ST1). All newborns had peripheral access and previously received β-lactams therapy...
October 26, 2017: Journal of Hospital Infection
https://www.readbyqxmd.com/read/29098663/antibiotics-reduce-retinal-cell-survival-in-vitro
#19
Amy E Lindsey, Ellen Townes-Anderson
Antibiotics such as gentamicin (an aminoglycoside) and penicillin (a beta-lactam antibiotic) are routinely used in retinal cell and explant cultures. In many cases, these in vitro systems are testing parameters regarding photoreceptor transplantation or preparing cells for transplantation. In vivo, milligram doses of gentamicin are neurotoxic to the retina. However, little is known about the effects of antibiotics to retina in vitro and whether smaller doses of gentamicin are toxic to retinal cells. To test toxicity, retinal cells were dissociated from tiger salamander, placed in culture, and treated with either 20 μg/ml gentamicin, 100 μg/ml streptomycin, 100 U/ml antibiotic/antimycotic, 0...
November 2, 2017: Neurotoxicity Research
https://www.readbyqxmd.com/read/29091730/probing-the-interaction-of-aspergillomarasmine-a-with-metallo-%C3%AE-lactamases-ndm-1-vim-2-and-imp-7
#20
Alexander Bergstrom, Andrew Katko, Zach Adkins, Jessica Hill, Zishuo Cheng, Mia Burnett, Hao Yang, Mahesh Aitha, M Rachel Mehaffey, Jennifer S Brodbelt, Kamaleddin H M E Tehrani, Nathaniel I Martin, Robert A Bonomo, Richard C Page, David L Tierney, Walter Fast, Gerard D Wright, Michael W Crowder
Metallo-β-lactamases (MBLs) are a growing threat to the continued efficacy of β-lactam antibiotics. Recently, aspergillomarasmine A (AMA) was identified as an MBL inhibitor, but the mode of inhibition was not fully characterized. Equilibrium dialysis and metal analysis studies revealed that 2 equiv of AMA effectively removes 1 equiv of Zn(II) from MBLs NDM-1, VIM-2, and IMP-7 when the MBL is at micromolar concentrations. Conversely, 1H NMR studies revealed that 2 equiv of AMA remove 2 equiv of Co(II) from Co(II)-substituted NDM-1, VIM-2, and IMP-7 when the MBL/AMA are at millimolar concentrations...
November 9, 2017: ACS Infectious Diseases
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