scholarly journals TEM-158 (CMT-9), a New Member of the CMT-Type Extended-Spectrum β-Lactamases

2007 ◽  
Vol 51 (11) ◽  
pp. 4181-4183 ◽  
Author(s):  
Frédéric Robin ◽  
Julien Delmas ◽  
Amélie Brebion ◽  
Damien Dubois ◽  
Jean-Michel Constantin ◽  
...  
Keyword(s):  
Hydrolytic Activity ◽  
Detection Methods ◽  
Extended Spectrum ◽  
Accurate Detection ◽  
High Level

ABSTRACT TEM-158 was found to include the substitutions previously observed for TEM-12 and TEM-35. This enzyme presented hydrolytic activity against ceftazidime and a high level of resistance against clavulanate, which can alter its detection. Its discovery highlights the need for accurate detection methods.

scholarly journals CMT-Type β-Lactamase TEM-125, an Emerging Problem for Extended-Spectrum β-Lactamase Detection

2006 ◽  
Vol 50 (7) ◽  
pp. 2403-2408 ◽  
Author(s):  
Frédéric Robin ◽  
Julien Delmas ◽  
Maryse Archambaud ◽  
Cédric Schweitzer ◽  
Catherine Chanal ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Clinical Laboratory ◽  
Hydrolytic Activity ◽  
Detection Methods ◽  
Clinical Strain ◽  
National Guidelines ◽  
French Society ◽  
Extended Spectrum ◽  
Need To Evaluate ◽  
High Level

ABSTRACT The clinical strain Escherichia coli TO799 was resistant to penicillin-clavulanate combinations and ceftazidime and was not reproducibly detected as an extended-spectrum β-lactamase (ESBL) according to the standards of the Clinical Laboratory Standards Institute (CLSI; formerly NCCLS) and the national guidelines of the French Society for Microbiology (Comité de l'Antibiogramme de la Société Française de Microbiologie). A novel β-lactamase, designated TEM-125, was responsible for this phenotype. TEM-125 harbors a complex association of mutations previously described in the ESBL TEM-12 and in the inhibitor-resistant β-lactamase TEM-39. TEM-125 is the first complex mutant TEM to present hydrolytic activity against ceftazidime (k cat, 3.7 s−1) together with a high level of resistance to clavulanate (50% inhibitory concentration, 13.6 μM). The discovery of such an ESBL, which is difficult to detect by the usual ESBL detection methods, confirms the emergence of a complex mutant TEM subgroup and highlights the need to evaluate detection methods so as to avoid possible therapeutic failures.

scholarly journals Mutational Events in Cefotaximase Extended-Spectrum β-Lactamases of the CTX-M-1 Cluster Involved in Ceftazidime Resistance

2008 ◽  
Vol 52 (7) ◽  
pp. 2377-2382 ◽  
Author(s):  
Ângela Novais ◽  
Rafael Cantón ◽  
Teresa M. Coque ◽  
Andrés Moya ◽  
Fernando Baquero ◽  
...  
Keyword(s):  
Hydrolytic Activity ◽  
Pleiotropic Effect ◽  
Site Directed Mutagenesis ◽  
Clinical Environment ◽  
M 10 ◽  
Extended Spectrum ◽  
High Level ◽  
Combined Strategy

ABSTRACT CTX-M β-lactamases, which show a high cefotaxime hydrolytic activity, constitute the most prevalent extended-spectrum β-lactamase (ESBL) type found among clinical isolates. The recent explosive diversification of CTX-M enzymes seems to have taken place due to the appearance of more efficient enzymes which are capable of hydrolyzing both cefotaxime and ceftazidime, especially among the CTX-M-1 cluster. A combined strategy of in vitro stepwise evolution experiments using bla CTX-M-1, bla CTX-M-3, and bla CTX-M-10 genes and site-directed mutagenesis has been used to evaluate the role of ceftazidime and other β-lactam antibiotics in triggering the diversity found among enzymes belonging to this cluster. Two types of mutants, P167S and D240G, displaying high ceftazidime MICs but reduced resistance to cefotaxime and/or cefepime, respectively, were identified. Such an antagonistic pleiotropic effect was particularly evident with P167S/T mutations. The incompatibility between P167S and D240G changes was demonstrated, since double mutants reduced susceptibility to both ceftazidime and cefotaxime-cefepime; this may explain the absence of strains containing both mutations in the clinical environment. The role of A77V and N106S mutations, which are frequently associated with P167S/T and/or D240G, respectively, in natural strains, was investigated. The presence of A77V and N106S contributes to restore a high-level cefotaxime resistance phenotype, but only when associated with mutations P167S and D240G, respectively. However, A77V mutation increases resistance to both cefotaxime and ceftazidime when associated with CTX-M-10. This suggests that in this context this mutation might be considered a primary site involved in resistance to broad-spectrum cephalosporins.

scholarly journals Real-Time Adversarial Attack Detection with Deep Image Prior Initialized as a High-Level Representation Based Blurring Network

Electronics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 52
Author(s):  
Richard Evan Sutanto ◽  
Sukho Lee
Keyword(s):  
Neural Network ◽  
Attack Detection ◽  
Detection Methods ◽  
Defense System ◽  
Image Prior ◽  
The Neural Network ◽  
Adversarial Examples ◽  
Deep Image ◽  
Adversarial Attack ◽  
High Level

Several recent studies have shown that artificial intelligence (AI) systems can malfunction due to intentionally manipulated data coming through normal channels. Such kinds of manipulated data are called adversarial examples. Adversarial examples can pose a major threat to an AI-led society when an attacker uses them as means to attack an AI system, which is called an adversarial attack. Therefore, major IT companies such as Google are now studying ways to build AI systems which are robust against adversarial attacks by developing effective defense methods. However, one of the reasons why it is difficult to establish an effective defense system is due to the fact that it is difficult to know in advance what kind of adversarial attack method the opponent is using. Therefore, in this paper, we propose a method to detect the adversarial noise without knowledge of the kind of adversarial noise used by the attacker. For this end, we propose a blurring network that is trained only with normal images and also use it as an initial condition of the Deep Image Prior (DIP) network. This is in contrast to other neural network based detection methods, which require the use of many adversarial noisy images for the training of the neural network. Experimental results indicate the validity of the proposed method.

scholarly journals Robust α-synuclein pathology in select brainstem neuronal populations is a potential instigator of multiple system atrophy

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ethan W. Hass ◽  
Zachary A. Sorrentino ◽  
Grace M. Lloyd ◽  
Nikolaus R. McFarland ◽  
Stefan Prokop ◽  
...  
Keyword(s):  
Multiple System Atrophy ◽  
Lewy Bodies ◽  
Biochemical Properties ◽  
Detection Methods ◽  
Inferior Olivary Nucleus ◽  
Cytoplasmic Inclusions ◽  
Neuronal Populations ◽  
Carboxy Terminal Region ◽  
High Level ◽  
Carboxy Terminal

AbstractMultiple system atrophy (MSA) is an insidious middle age-onset neurodegenerative disease that clinically presents with variable degrees of parkinsonism and cerebellar ataxia. The pathological hallmark of MSA is the progressive accumulation of glial cytoplasmic inclusions (GCIs) in oligodendrocytes that are comprised of α-synuclein (αSyn) aberrantly polymerized into fibrils. Experimentally, MSA brain samples display a high level of seeding activity to induce further αSyn aggregation by a prion-like conformational mechanism. Paradoxically, αSyn is predominantly a neuronal brain protein, with only marginal levels expressed in normal or diseased oligodendrocytes, and αSyn inclusions in other neurodegenerative diseases, including Parkinson’s disease and Dementia with Lewy bodies, are primarily found in neurons. Although GCIs are the hallmark of MSA, using a series of new monoclonal antibodies targeting the carboxy-terminal region of αSyn, we demonstrate that neuronal αSyn pathology in MSA patient brains is remarkably abundant in the pontine nuclei and medullary inferior olivary nucleus. This neuronal αSyn pathology has distinct histological properties compared to GCIs, which allows it to remain concealed to many routine detection methods associated with altered biochemical properties of the carboxy-terminal domain of αSyn. We propose that these previously underappreciated sources of aberrant αSyn could serve as a pool of αSyn prion seeds that can initiate and continue to drive the pathogenesis of MSA.

scholarly journals An IS1-like element is responsible for high-level synthesis of extended-spectrum  -lactamase TEM-6 in Enterobacteriaceae

1991 ◽  
Vol 137 (12) ◽  
pp. 2681-2687 ◽  
Author(s):  
S. Goussard ◽  
W. Sougakoff ◽  
C. Mabilat ◽  
A. Bauernfeind ◽  
P. Courvalin
Keyword(s):  
High Level Synthesis ◽  
Extended Spectrum ◽  
High Level

scholarly journals ANTIMICROBIAL SUSCEPTIBILITY AND DETECTION METHODS FOR THE EXTENDED‑SPECTRUM β-LACTAMASES PRODUCING ENTEROBACTERIACEAE FROM CLINICAL SAMPLES

2018 ◽  
Vol 11 (5) ◽  
pp. 139
Author(s):  
Kaviyarasan G ◽  
Rajamanikandan Kcp ◽  
Sabarimuthu M ◽  
Ramya S ◽  
Arvind Prasanth D
Keyword(s):  
Infection Control ◽  
Bacterial Infections ◽  
Control Measures ◽  
Detection Methods ◽  
Clinical Samples ◽  
Healthcare Settings ◽  
Infection Control Measures ◽  
Extended Spectrum ◽  
Drug Choice ◽  
Synergy Test

Objectives: Detection of extended-spectrum β-lactamases (ESBLs) is crucial for the infection control and antibiotic choice in healthcare settings. The aim of this study is to develop a standardized, inexpensive, and simple approach that is able to detect ESBL-producing Enterobacteriaceae isolates.Methods: Isolates those were resistant to at least one of the three indicator cephalosporins (cefotaxime, cefpodoxime, and ceftazidime) were tested for ESBL production using the double disc synergy test (DDST), combined disc synergy test (CDST) test and genotypic detection of the responsible gene for the ESBL.Result: From 64 isolates, 28 were resistant to cephalosporins. In 28 isolates, 23 were positive in CDST but in the DDST 18 were showing ESBL positive. 10 were positive in both CDST and DDST.Conclusion: Resistance to cephalosporins, which are the drug choice to treat mixed bacterial infections by the Enterobacteriaceae of which disseminate rapidly being plasmid mediated. Hence, it is necessary that rapid detection of ESBL should be done and immediate infection control measures should be implemented to prevent their dissemination.

scholarly journals Molecular Analyses of TEM Genes and Their Corresponding Penicillinase-Producing Neisseria gonorrhoeae Isolates in Bangkok, Thailand

2011 ◽  
Vol 56 (2) ◽  
pp. 916-920 ◽  
Author(s):  
Shu-ichi Nakayama ◽  
Chanwit Tribuddharat ◽  
Sasiprapa Prombhul ◽  
Ken Shimuta ◽  
Somporn Srifuengfung ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Public Health Problem ◽  
Major Public Health Problem ◽  
Sexual Network ◽  
Genetic Event ◽  
Content Type ◽  
Extended Spectrum ◽  
Resistance To Penicillin ◽  
High Level ◽  
International Awareness

ABSTRACTNeisseria gonorrhoeaeis a major public health problem globally, especially because the bacterium has developed resistance to most antimicrobials introduced for first-line treatment of gonorrhea. In the present study, 96N. gonorrhoeaeisolates with high-level resistance to penicillin from 121 clinical isolates in Thailand were examined to investigate changes related to their plasmid-mediated penicillin resistance and their molecular epidemiological relationships. A β-lactamase (TEM) gene variant,blaTEM-135, that may be a precursor in the transitional stage of a traditionalblaTEM-1gene into an extended-spectrum β-lactamase (ESBL), possibly causing high resistance to all extended-spectrum cephalosporins inN. gonorrhoeae, was identified. Clonal analysis using multilocus sequence typing (MLST) andN. gonorrhoeaemultiantigen sequence typing (NG-MAST) revealed the existence of a sexual network among patients from Japan and Thailand. Molecular analysis of theblaTEM-135gene showed that the emergence of this allele might not be a rare genetic event and that the allele has evolved in different plasmid backgrounds, which results possibly indicate that it is selected due to antimicrobial pressure. The presence of theblaTEM-135allele in the penicillinase-producingN. gonorrhoeaepopulation may call for monitoring for the possible emergence of ESBL-producingN. gonorrhoeaein the future. This study identified ablaTEMvariant (blaTEM-135) that is a possible intermediate precursor for an ESBL, which warrants international awareness.

scholarly journals Molecular Fingerprints of Hemoglobin on a Nanofilm Chip

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3016 ◽  
Author(s):  
Yeşeren Saylan ◽  
Adil Denizli
Keyword(s):  
Real Time ◽  
Theoretical Calculations ◽  
Essential Element ◽  
Hemoglobin Concentration ◽  
Ammonium Persulfate ◽  
Detection Methods ◽  
Molecular Fingerprints ◽  
Molecularly Imprinted ◽  
On Chip ◽  
High Level

Hemoglobin is an iron carrying protein in erythrocytes and also an essential element to transfer oxygen from the lungs to the tissues. Abnormalities in hemoglobin concentration are closely correlated with health status and many diseases, including thalassemia, anemia, leukemia, heart disease, and excessive loss of blood. Particularly in resource-constrained settings existing blood analyzers are not readily applicable due to the need for high-level instrumentation and skilled personnel, thereby inexpensive, easy-to-use, and reliable detection methods are needed. Herein, a molecular fingerprints of hemoglobin on a nanofilm chip was obtained for real-time, sensitive, and selective hemoglobin detection using a surface plasmon resonance system. Briefly, through the photopolymerization technique, a template (hemoglobin) was imprinted on a monomeric (acrylamide) nanofilm on-chip using a cross-linker (methylenebisacrylamide) and an initiator-activator pair (ammonium persulfate-tetramethylethylenediamine). The molecularly imprinted nanofilm on-chip was characterized by atomic force microscopy and ellipsometry, followed by benchmarking detection performance of hemoglobin concentrations from 0.0005 mg mL−1 to 1.0 mg mL−1. Theoretical calculations and real-time detection implied that the molecularly imprinted nanofilm on-chip was able to detect as little as 0.00035 mg mL−1 of hemoglobin. In addition, the experimental results of hemoglobin detection on the chip well-fitted with the Langmuir adsorption isotherm model with high correlation coefficient (0.99) and association and dissociation coefficients (39.1 mL mg−1 and 0.03 mg mL−1) suggesting a monolayer binding characteristic. Assessments on selectivity, reusability and storage stability indicated that the presented chip is an alternative approach to current hemoglobin-targeted assays in low-resource regions, as well as antibody-based detection procedures in the field. In the future, this molecularly imprinted nanofilm on-chip can easily be integrated with portable plasmonic detectors, improving its access to these regions, as well as it can be tailored to detect other proteins and biomarkers.

Prevalence of extended-spectrum β-lactamase-producing Escherichia coli and residual antimicrobials in the environment in Vietnam

2017 ◽  
Vol 18 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Shinji Yamasaki ◽  
Tuyen Danh Le ◽  
Mai Quang Vien ◽  
Chinh Van Dang ◽  
Yoshimasa Yamamoto
Keyword(s):  
Escherichia Coli ◽  
Critical Role ◽  
Environmental Water ◽  
Resistant Bacteria ◽  
Human Beings ◽  
E Coli ◽  
Extended Spectrum ◽  
High Prevalence ◽  
Food Animals ◽  
High Level

AbstractEmergence and spread of antimicrobial-resistant bacteria, including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, have become serious problems worldwide. Recent studies conducted in Vietnam revealed that ESBL-producing E. coli are widely distributed in food animals and people. CTX-M-9 and CTX-M-1 are the most prevalent β-lactamases among the identified ESBLs. Furthermore, most of the ESBL-producing E. coli isolates were multi-drug resistant. Residual antimicrobials such as sulfamethoxazole, trimethoprim, sulfadimidine, cephalexin, and sulfadiazine were also detected at a high level in both animal meats and environmental water collected from several cities, including Ho Chi Minh city and Can Tho city. These recent studies indicated that improper use of antimicrobials in animal-originated food production might contribute to the emergence and high prevalence of ESBL-producing E. coli in Vietnam. Although clonal ESBL-producing E. coli was not identified, CTX-M-55 gene-carrying plasmids with similar sizes (105–139 kb) have been commonly detected in the ESBL-producing E. coli strains isolated from various food animals and human beings. This finding strongly suggests that horizontal transfer of the CTX-M plasmid among various E. coli strains played a critical role in the emergence and high prevalence of ESBL-producing E. coli in Vietnam.

scholarly journals A TEM-derived extended-spectrum beta-lactamase in Pseudomonas aeruginosa.

1996 ◽  
Vol 40 (11) ◽  
pp. 2488-2493 ◽  
Author(s):  
P Mugnier ◽  
P Dubrous ◽  
I Casin ◽  
G Arlet ◽  
E Collatz
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Clinical Strain ◽  
Beta Lactamase ◽  
Beta Lactam ◽  
Aminoglycoside Resistance ◽  
Double Mutation ◽  
Extended Spectrum Beta Lactamase ◽  
Beta Lactam Antibiotics ◽  
Extended Spectrum ◽  
High Level

A clinical strain of Pseudomonas aeruginosa, PAe1100, was found to be resistant to all antipseudomonal beta-lactam antibiotics and to aminoglycosides, including gentamicin, amikacin, and isepamicin. PAe1100 produced two beta-lactamases, TEM-2 (pI 5.6) and a novel, TEM-derived extended-spectrum beta-lactamase called TEM-42 (pI 5.8), susceptible to inhibition by clavulanate, sulbactam, and tazobactam. Both enzymes, as well as the aminoglycoside resistance which resulted from AAC(3)-IIa and AAC(6')-I production, were encoded by an 18-kb nonconjugative plasmid, pLRM1, that could be transferred to Escherichia coli by transformation. The gene coding for TEM-42 had four mutations that led to as many amino acid substitutions with respect to TEM-2: Val for Ala at position 42 (Ala42), Ser for Gly238, Lys for Glu240, and Met for Thr265 (Ambler numbering). The double mutation Ser for Gly238 and Lys for Glu240, which has so far only been described in SHV-type but not TEM-type enzymes, conferred concomitant high-level resistance to cefotaxime and ceftazidime. The novel, TEM-derived extended-spectrum beta-lactamase appears to be the first of its class to be described in P. aeruginosa.

Sign in / Sign up

Export Citation Format

Share Document