scholarly journals Mycobacterium Species Identification and Rifampin Resistance Testing with High-Density DNA Probe Arrays

1999 ◽  
Vol 37 (1) ◽  
pp. 49-55 ◽  
Author(s):  
A. Troesch ◽  
H. Nguyen ◽  
C. G. Miyada ◽  
S. Desvarenne ◽  
T. R. Gingeras ◽  
...  
Keyword(s):  
Species Identification ◽  
Susceptibility Testing ◽  
Genetic Material ◽  
Dna Probe ◽  
Resistance Testing ◽  
Bacterial Diseases ◽  
Parallel Testing ◽  
Assay Time ◽  
Rifampin Resistance ◽  
Rrna Sequences

Species identification within the genus Mycobacteriumand subsequent antibiotic susceptibility testing still rely on time-consuming, culture-based methods. Despite the recent development of DNA probes, which greatly reduce assay time, there is a need for a single platform assay capable of answering the multitude of diagnostic questions associated with this genus. We describe the use of a DNA probe array based on two sequence databases: one for the species identification of mycobacteria (82 unique 16S rRNA sequences corresponding to 54 phenotypical species) and the other for detectingMycobacterium tuberculosis rifampin resistance (rpoB alleles). Species identification or rifampin resistance was determined by hybridizing fluorescently labeled, amplified genetic material generated from bacterial colonies to the array. Seventy mycobacterial isolates from 27 different species and 15 rifampin-resistant M. tuberculosis strains were tested. A total of 26 of 27 species were correctly identified as well as all of the rpoB mutants. This parallel testing format opens new perspectives in terms of patient management for bacterial diseases by allowing a number of genetic tests to be simultaneously run.

scholarly journals REP-PCR analisis of single agent of cucumber bacterial diseases

2017 ◽  
Vol 15 (1) ◽  
pp. 25-31
Author(s):  
L. A. Dankevych
Keyword(s):  
Species Identification ◽  
Statistical Methods ◽  
Genetic Heterogeneity ◽  
Significant Relationship ◽  
Molecular Genetic ◽  
Single Agent ◽  
Genetic Homogeneity ◽  
Bacterial Diseases ◽  
Typical Strain ◽  
Correct Species Identification

Aim. For the purpose of correct species identification and estimation of population’s heterogeneity, the fingerprinting of the genome of isolated by us Pectobacterium sp., collection «Erwinia toxica» strains and typical representatives of certain species of Pectobacterium and Diskeya genera has been carried out. Methods. In the course of research, microbiological, molecular genetic (REP-PCR), mathematical-statistical methods of research were used. Results. On the basic of BOX, REP and ERIC profiles the significant affinity between isolated Pectobacterium sp. and collections «Erwinia toxica» strains with the typical P. carotovorum susp. carotovorum UCM B1075T has been established. Genetic heterogeneity of isolated Pectobacterium sp. and collections «Erwinia toxica» strains has been estimated. Conclusions. It has been found the significant relationship between isolates Pectobacterium sp. and the collection «Erwinia toxica» strains with the typical strain P. carotovorum susp carotovorum UCM B1075T on the basic of their BOX, REP and ERIC profiles. Most likely, this indicates that they belong to this species. The genetic homogeneity of isolated Pectobacterium sp. strains of and the genetic heterogeneity of the collection «Erwinia toxica» strains is probably due to the plant’s selection from similar or different region.Keywords: identification, genetic heterogeneity, REPPCR, «Erwinia toxica», Pectobacterium sp.

scholarly journals 655. Detection of Antibiotic Resistance Genes in Clinical Samples using T2 Magnetic Resonance

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S301-S301
Author(s):  
Jessica L Snyder ◽  
Brendan Manning ◽  
Robert Shivers ◽  
Daniel Gamero ◽  
Heidi Giese ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Magnetic Resonance ◽  
Species Identification ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Resistance Testing ◽  
Clinical Samples ◽  
Antibiotic Resistant ◽  
Blood Samples ◽  
Culture Independent

Abstract Background Antibiotic-resistant bacteria are spread through selective pressure from the use of broad-spectrum empirical therapies, mobile genetic elements that pass resistance genes between species, and the inability to rapidly and appropriately respond to their presence. Resistance gene identification is often performed with post culture molecular diagnostic tests. The T2Resistance Panel, which detects methicillin resistance genes mecA/C; vancomycin resistance genes vanA/B; carbapenemases blaKPC, blaOXA-48,blaNDM, blaVIM, and blaIMP; AmpC β-lactamases blaCMY and blaDHA; and extended-spectrum β-lactamases blaCTX-M directly from patient blood samples, is based on T2 magnetic resonance (T2MR), an FDA-cleared technology with demonstrated high sensitivity and specificity for culture-independent bacterial and fungal species identification. Here we report the clinical performance of T2MR detection of resistance genes directly from patient blood samples. Methods Patients with a clinical diagnosis of sepsis and an order for blood culture (BC) were enrolled in the study at two sites. BCs were managed using standard procedures and MALDI-TOF for species identification. Resistance testing with the T2MR assay was performed on a direct patient draw and compared with diagnostic test results from concurrent BC specimen and BC specimen taken at other points in time. The potential impact on therapy was evaluated through patient chart review. Results T2MR detected the same resistance genes as detected by post culture diagnostics in 100% of samples from concurrent blood draws. Discordant results occurred when T2MR was taken ≥48 hours after BC for patients on antimicrobial therapy. The average time to positive result was 5.9 hours with T2MR vs. 30.6 hours with post-culture molecular testing. Conclusion The T2Resistance Panel detected antibiotic resistance genes in clinical samples and displayed agreement with post culture genetic testing. T2MR results were achieved faster than culture-dependent diagnostic testing results and may allow for an earlier change from empiric to directed therapy. The use of culture-independent diagnostics like T2MR could enable a quicker response to antibiotic-resistant organisms for individual patients and developing outbreaks. Disclosures All authors: No reported disclosures.

scholarly journals External Quality Assessment of Bacterial Identification and Antimicrobial Susceptibility Testing in African National Public Health Laboratories, 2011–2016

2019 ◽  
Vol 4 (4) ◽  
pp. 144 ◽  
Author(s):  
Olga Perovic ◽  
Ali A. Yahaya ◽  
Crystal Viljoen ◽  
Jean-Bosco Ndihokubwayo ◽  
Marshagne Smith ◽  
...  
Keyword(s):  
Public Health ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
External Quality Assessment ◽  
Antimicrobial Susceptibility Testing ◽  
Bacterial Identification ◽  
African Region ◽  
External Quality ◽  
Bacterial Diseases ◽  
National Public Health

Background: In 2002, the World Health Organization (WHO) launched a regional microbiology external quality assessment (EQA) programme for national public health laboratories in the African region, initially targeting priority epidemic-prone bacterial diseases, and later including other common bacterial pathogens. Objectives: The aim of this study was to analyse the efficacy of an EQA programme as a laboratory quality system evaluation tool. Methods: We analysed the proficiency of laboratories’ performance of bacterial identification and antimicrobial susceptibility testing (AST) for the period 2011–2016. The National Institute for Communicable Diseases of South Africa provided technical coordination following an agreement with WHO, and supplied EQA samples of selected bacterial organisms for microscopy (Gram stain), identification, and antimicrobial susceptibility testing (AST). National public health laboratories, as well as laboratories involved in the Invasive Bacterial Diseases Surveillance Network, were enrolled by the WHO Regional Office for Africa to participate in the EQA programme. We analysed participants’ results of 41 surveys, which included the following organisms sent as challenges: Streptococcus pneumonia, Haemophilus influenzae, Neisseria meningitidis, Salmonella Typhi, Salmonella Enteritidis, Shigella flexneri, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus anginosus, Enterococcus faecium, Serratia marcescens, Acinetobacter baumannii, and Enterobacter cloacae. Results: Eighty-one laboratories from 45 countries participated. Overall, 76% of participants obtained acceptable scores for identification, but a substantial proportion of AST scores were not in the acceptable range. Of 663 assessed AST responses, only 42% had acceptable scores. Conclusion: In the African Region, implementation of diagnostic stewardship in clinical bacteriology is generally suboptimal. This report illustrates that AST is poorly done compared to microscopy and identification. It is critically important to make the case for implementation of quality assurance in AST, as it is the cornerstone of antimicrobial resistance surveillance reporting and implementation of the Global Antimicrobial Resistance Surveillance System.

scholarly journals Detecting Azole-Antifungal Resistance in Aspergillus fumigatus by Pyrosequencing

2020 ◽  
Vol 6 (1) ◽  
pp. 12 ◽  
Author(s):  
Mireille H. van der Torre ◽  
Lilyann Novak-Frazer ◽  
Riina Rautemaa-Richardson
Keyword(s):  
Dna Sequencing ◽  
Susceptibility Testing ◽  
Simultaneous Detection ◽  
Drug Susceptibility ◽  
Turnaround Time ◽  
Fungal Species ◽  
Antifungal Resistance ◽  
Diagnostic Methods ◽  
Resistance Testing ◽  
Clinical Samples

Guidelines on the diagnosis and management of Aspergillus disease recommend a multi-test approach including CT scans, culture, fungal biomarker tests, microscopy and fungal PCR. The first-line treatment of confirmed invasive aspergillosis (IA) consists of drugs in the azole family; however, the emergence of azole-resistant isolates has negatively impacted the management of IA. Failure to detect azole-resistance dramatically increases the mortality rates of azole-treated patients. Despite drug susceptibility tests not being routinely performed currently, we suggest including resistance testing whilst diagnosing Aspergillus disease. Multiple tools, including DNA sequencing, are available to screen for drug-resistant Aspergillus in clinical samples. This is particularly beneficial as a large proportion of IA samples are culture negative, consequently impeding susceptibility testing through conventional methods. Pyrosequencing is a promising in-house DNA sequencing method that can rapidly screen for genetic hotspots associated with antifungal resistance. Pyrosequencing outperforms other susceptibility testing methods due to its fast turnaround time, accurate detection of polymorphisms within critical genes, including simultaneous detection of wild type and mutated sequences, and—most importantly—it is not limited to specific genes nor fungal species. Here we review current diagnostic methods and highlight the potential of pyrosequencing to aid in a diagnosis complete with a resistance profile to improve clinical outcomes.

Antimicrobial susceptibility testing by using virulent phages to evaluate bacterial viability

2018 ◽  
Vol 10 (16) ◽  
pp. 1799-1804 ◽  
Author(s):  
Yong He ◽  
Enci Fan ◽  
Mengyao Wang ◽  
Shuguang Lu ◽  
Zhifeng Fu
Keyword(s):  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Resistance Testing ◽  
Antibiotic Exposure ◽  
Bacterial Viability ◽  
Phenotypic Resistance

A protocol for antibiotic phenotypic resistance testing was developed by using virulent phages to evaluate bacterial viability after antibiotic exposure.

scholarly journals Short Incubation of Positive Blood Cultures on Solid Media for Species Identification by MALDI-TOF MS: Which Agar Is the Fastest?

2021 ◽  
Author(s):  
Neele J. Froböse ◽  
Evgeny A. Idelevich ◽  
Frieder Schaumburg
Keyword(s):  
Mass Spectrometry ◽  
Species Identification ◽  
Susceptibility Testing ◽  
Solid Medium ◽  
Blood Cultures ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Solid Media ◽  
Laboratory Results ◽  
Tof Ms

When blood cultures are flagged as positive, they are incubated on solid media to produce enough biomass of the bacterium for identification and susceptibility testing. Rapid turnaround times for laboratory results could save lives, and we wanted to assess which solid medium is best to shorten the time to species identification using MALDI-TOF mass spectrometry.

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