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b lactamics

Karmen Godič Torkar, Branka Bedenić
The susceptibility of 66 clinical and environmental B. cereus isolates were tested to selected antimicrobials by a broth microdilution method. All strains were resistant to β-lactams and susceptible to gentamicin and imipenem. Sixty-five (98.5%) isolates were susceptible to meropenem and ciprofloxacin and 74.2% to azithromycin. Significant differences in MIC values between environmental and clinical isolates were not demonstrated (p > 0.05). According to the disc diffusion method, 80.3%-98.5% of the strains were resistant to one or more of four cephalosporins...
March 15, 2018: Microbial Pathogenesis
Laura Bonofiglio, Paula Gagetti, Gabriela García Gabarrot, Sara Kaufman, Marta Mollerach, Inés Toresani, Laura Vigliarolo, Martha von Specht, Horacio A Lopardo
Group A (GAS), B (GBS), C (GCS) and G (GGS) β-hemolytic streptococci are important human pathogens. They cause infections of different severity and frequency. Nowadays, after 70 years of use, penicillin is still universally active against GAS, GCS and GGS. However, therapeutic failures have been recorded in 2-28% of pharyngitis cases (median: 12%) attributable to different causes. By contrast, some GBS with reduced susceptibility to penicillin have been described, especially in Japan. In this group of bacteria, it is important to highlight that confirmation by reference methods is mandatory when decreased susceptibility to penicillin is suspected as well as checked for the detection of the mechanisms involved...
March 13, 2018: Revista Argentina de Microbiología
Diego B Nobrega, Sohail Naushad, S Ali Naqvi, Larissa A Z Condas, Vineet Saini, John P Kastelic, Christopher Luby, Jeroen De Buck, Herman W Barkema
Emergence and spread of antimicrobial resistance is a major concern for the dairy industry worldwide. Objectives were to determine: (1) phenotypic and genotypic prevalence of drug-specific resistance for 25 species of non-aureus staphylococci, and (2) associations between presence of resistance determinants and antimicrobial resistance. Broth micro-dilution was used to determine resistance profiles for 1,702 isolates from 89 dairy herds. Additionally, 405 isolates were sequenced to screen for resistance determinants...
2018: Frontiers in Microbiology
Yoel Gil, Yonit Well-Weiner, Tod Zalut, Reuven Friedmann, Amos M Yinnon, Eli Ben-Chetrit
Blood cultures' contamination (BCC) is associated with unnecessary processing of cultures, higher cost, and occasionally, unjustified antibiotic treatment. We aimed to reduce the rate of BCC by educational intervention. In parallel, we also strove to expand the use of aminoglycosides (AMG) and reduce the utilization of beta-lactam antibiotics. The rate of BCC was assessed prospectively in the study department - the Emergency Department (ED) and in control departments - Medical Departments A, B and Geriatrics...
February 2018: Harefuah
M N Islam, D Ahmed, M A Hossain, C R Ahsan, M Yasmin
Antimicrobial drug resistance, a global concern, has been increasing unpredictably in microorganism causing human infections specially among Gram negative non-fermenting Pseudomonas spp. Carbapenems, a beta lactam antibiotics, are the most potent and effective drug usually kept reserved for treating the multi-drug resistant Psedomonas spp and other infections caused by organisms producing Extended Spectrum Beta Lactamase (ESBL) and AmpC. Clinical utility of carbapenem will reduce when resistant bacteria evolve due to production of carbapenem hydrolyzing Metallo-β-lactamase (MBL) which confers high-level resistance to all beta-lactam antibiotics except aztreonam...
January 2018: Mymensingh Medical Journal: MMJ
Edina Szekeres, Cecilia Maria Chiriac, Andreea Baricz, Tiberiu Szőke-Nagy, Ildiko Lung, Maria-Loredana Soran, Knut Rudi, Nicolae Dragos, Cristian Coman
Groundwater is an essential public and drinking water supply and its protection is a goal for global policies. Here, we investigated the presence and prevalence of antibiotic residues, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial contamination in groundwater environments at various distances from urban areas. Antibiotic concentrations ranged from below detection limit to 917 ng/L, being trimethoprim, macrolide, and sulfonamide the most abundant antibiotic classes. A total of eleven ARGs (aminoglycoside, β-lactam, chloramphenicol, Macrolide-Lincosamide-Streptogramin B - MLSB, sulfonamide, and tetracycline), one antiseptic resistance gene, and two MGEs were detected by qPCR with relative abundances ranging from 6...
February 14, 2018: Environmental Pollution
Marjan Rashidan, Masoumeh Azimirad, Masoud Alebouyeh, Mehdi Ghobakhlou, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali
We compared frequency of the members of B. fragilis group in 100 and 20 colon biopsy specimens of inflammatory bowel disease (IBD) and non-IBD patients. Agar dilution and PCR were orderly used to detect minimal inhibitory concentration of ampicillin, imipenem, and metronidazole, and carriage of related resistance genes cepA, cfi, and nim. B. fragilis group was detected in 38% of IBD (UC: 36/89; CD:1/11) and 25% (5/20) of non-IBD patients. While B. vulgatus (UC: 20/36, CD: 1/2, control: 1/6); B. fragilis (UC: 18/36, CD: 1/2, control: 5/6); B...
February 14, 2018: Anaerobe
Assèta Kagambèga, Taru Lienemann, Jonathan G Frye, Nicolas Barro, Kaisa Haukka
Background: Multidrug-resistant Salmonella is an important cause of morbidity and mortality in developing countries. The aim of this study was to characterize and compare multidrug-resistant Salmonella enterica serovar Typhimurium isolates from patients and poultry feces. Methods: Salmonella strains were isolated from poultry and patients using standard bacteriological methods described in previous studies. The strains were serotype according to Kaufmann-White scheme and tested for antibiotic susceptibility to 12 different antimicrobial agents using the disk diffusion method...
2018: Tropical Medicine and Health
Xiulan Weng, Wanling Cai, Ruifang Lan, Qian Sun, Zuliang Chen
This study examined functional bentonite-supported nanoscale Fe/Ni (B-Fe/Ni) for the simultaneous removal of β-lactam antibiotics such as amoxicillin (AMX), ampicillin (AMP) and penicillin (PEN). The results show only 94.6% of AMX, 80.6% of AMP and 53.7% of PEN were removed in the mixed antibiotic solution, while 97.5% of AMX, 85.1% of AMP and 74.5% of PEN were removed in individual antibiotic solution. The decreased removal in a mixed antibiotic solution was attributed to competition between antibiotics for: firstly, active sites of iron oxide for the adsorption; and secondly, accepted electrons for the degradation in passivation of the nZVI surface...
February 8, 2018: Environmental Pollution
Xiaoli Meng, Zaid Al-Attar, Fiazia S Yaseen, Rosalind Jenkins, Caroline Earnshaw, Paul Whitaker, Daniel Peckham, Neil S French, Dean J Naisbitt, B Kevin Park
No abstract text is available yet for this article.
February 2, 2018: Journal of Immunology: Official Journal of the American Association of Immunologists
Yelda Asad, Sajjad Ahmad, Thanyada Rungrotmongkol, Kara E Ranaghan, Syed Sikander Azam
The bacterium Providencia stuartii, is associated with urinary tract infections and is the most common cause of purple urine bag syndrome. The increasing multi-drug resistance pattern shown by the pathogen and lack of licensed vaccines make treatment of infections caused by P. stuartii challenging. As vaccinology data against the pathogen is scarce, an in silico proteome based Reverse Vaccinology (RV) protocol, in combination with subtractive proteomics is introduced in this work to screen potential vaccine candidates against P...
January 31, 2018: Journal of Molecular Graphics & Modelling
Phillip J Bergen, Jürgen B Bulitta, Fekade B Sime, Jeffrey Lipman, Megan J McGregor, Nada Millen, David L Paterson, Carl M J Kirkpatrick, Jason A Roberts, Cornelia B Landersdorfer
We described bacterial killing and resistance emergence at various fixed concentrations of meropenem and piperacillin/tazobactam against Pseudomonas aeruginosa and Escherichia coli. Time-kill studies were conducted utilizing nine isolates and a large range of concentrations. Within each strain and antibiotic, initial killing was similar, with concentrations ≥2×MIC. At many (strain-specific) concentrations causing substantial initial killing, regrowth occurred at 24-48h. For remaining concentrations, growth typically remained suppressed (<5-log10 cfu/mL)...
January 3, 2018: Diagnostic Microbiology and Infectious Disease
Dalton B Burks, Monica Vasiliu, David A Dixon, Elizabeth T Papish
The organic ligand 6,6'-dihydroxy-2,2'-bipyridine (6,6'-dhbp) is frequently used to bind transition metals in order to form catalysts for many organic and inorganic transformations. 6,6'-dhbp exists in two tautomeric forms, the pyridinol tautomer and the amide (lactam) tautomer with each tautomer having two rotational conformers: cis or trans. Only the cis-pyridinol tautomer has the proper configuration to bind transition metals. The pendant OH (or O- groups when deprotonated) in 6,6'-dhbp typically do not bind the metal when forming the metal catalyst but can facilitate the proton transfer steps in the catalysis process...
January 31, 2018: Journal of Physical Chemistry. A
D C Richter, A Heininger, T Brenner, M Hochreiter, M Bernhard, J Briegel, S Dubler, B Grabein, A Hecker, W A Kruger, K Mayer, M W Pletz, D Storzinger, N Pinder, T Hoppe-Tichy, S Weiterer, S Zimmermann, A Brinkmann, M A Weigand, C Lichtenstern
The mortality of patients with sepsis and septic shock is still unacceptably high. An effective calculated antibiotic treatment within 1 h of recognition of sepsis is an important target of sepsis treatment. Delays lead to an increase in mortality; therefore, structured treatment concepts form a rational foundation, taking relevant diagnostic and treatment steps into consideration. In addition to the assumed infection and individual risks of each patient, local resistance patterns and specific problem pathogens must be taken into account during the selection of anti-infective treatment...
January 30, 2018: Der Anaesthesist
Mitchell G Thompson, Nima Sedaghatian, Jesus F Barajas, Maren Wehrs, Constance B Bailey, Nurgul Kaplan, Nathan J Hillson, Aindrila Mukhopadhyay, Jay D Keasling
pSC101 is a narrow host range, low-copy plasmid commonly used for genetically manipulating Escherichia coli. As a byproduct of a genetic screen for a more sensitive lactam biosensor, we identified multiple novel mutations that increase the copy number of plasmids with the pSC101 origin. All mutations identified in this study occurred on plasmids which also contained at least one mutation localized to the RepA protein encoded within the origin. Homology modelling predicts that many of these mutations occur within the dimerization interface of RepA...
January 25, 2018: Scientific Reports
Valdemir Vicente da Silva Júnior, Laura Durão Ferreira, Lílian Rodrigues Alves, Adriane Borges Cabral, Paula Regina Luna de Araújo Jácome, Paulo Sérgio Ramos de Araújo, Ana Catarina de Souza Lopes, Maria Amélia Vieira Maciel
INTRODUCTION: Pseudomonas aeruginosa, an important pathogen globally, presents several resistance mechanisms. This study aimed to investigate the presence of bla GES in clinical isolates of Pseudomonas aeruginosa obtained from various clinical specimens from patients admitted to three different hospitals in Recife, Brazil. The Guiana extended spectrum beta-lactamase (GES) enzymes are responsible for conferring broad spectrum resistance to beta-lactam drugs, including the carbapenems. METHODS: A total of 100 carbapenem-resistant P...
November 2017: Revista da Sociedade Brasileira de Medicina Tropical
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
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
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
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
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