Detection Of Bacteria In Samples Research Articles

A New Method Based on LAMP-CRISPR-Cas12a-Lateral Flow Immunochromatographic Strip for Detection.

IntroductionCarbapenemase-mediated antimicrobial resistance is currently a hot spot of global concern. Carbapenem-resistant organisms are highly prevalent in hospitals associated with difficult-to-treat infections, resulting in poor clinical outcome due to limited treatment options. It is urgently needed to have a rapid, efficient, and convenient molecular assay for identifying such resistant strains.MethodsFor this end, we developed a new laboratory assay targeting Klebsiella pneumoniae carbapenemase (KPC) and New Delhi metallo-β-lactamase (NDM) based on loop-mediated isothermal amplification, CRISPR–Cas12a, and lateral flow immunochromatographic strip (CRISPR–Cas-LAMP-lateral flow strip). The method was designed to use a guide RNA (gRNA) to recognize the target DNA and guide Cas12a to cleave the target DNA, and simultaneously cleave any single-stranded DNA within the cleavage reaction system.ResultsThe cleavage products are visible to the naked eye on the lateral flow strip. This method is highly sensitive in direct detection of bacteria in samples containing at least 3×105 CFU/mL without the need for bacterial culture.DiscussionIt provides shorter turnaround time and higher specificity than the conventional bacterial culture and susceptibility testing method. This new assay is applicable for extensive use in hospital infection control, as well as identification and treatment of resistant strains due to simple operation and inexpensive apparatuses.

DNA Microarray-based Detection of Bacteria in Samples Containing Antibiotics: Effect of Antibiotics on the Performance of Pathogen Detection Assays

DNA Microarray-based Detection of Bacteria in Samples Containing Antibiotics: Effect of Antibiotics on the Performance of Pathogen Detection Assays

Antimicrobial peptide arrays for wide spectrum sensing of pathogenic bacteria

Fast detection of bacteria in samples presumed to be un-contaminated, such as blood, is of great importance. Indeed, rapid diagnosis allows the set-up of appropriate antibiotic treatment. Besides clinical issues, there are many other domains, such as food processing or drug manufacturing, where the strict absence of any bacteria has to be assessed. Because the bacterial load found in most contaminated samples is often below the limit of detection for currently validated assays, a preliminary enrichment step is required to allow bacterial multiplication before proceeding to the analysis step, whatever it might be – cultural, immunological or molecular methods. In this study, we describe the use of a biosensor for single-step bacteria detection. The whole analysis is performed in less than 20 h, during the growth phase of the micro-organisms, using an array of antimicrobial peptides (AMPs) coupled with a surface plasmon resonance imager (SPRI). A wide range of bacterial strains are assayed, showing differentiated affinity patterns with the immobilized peptides, which are confirmed by multivariate analysis. This work establishes the evidence that antimicrobial peptides, mostly used so far in the antibiotic drug industry, are suited for the wide-spectrum detection of unknown bacteria in samples, even at very low initial loads. Moreover, the small set of AMPs that were assayed provided a specific affinity profile for each pathogen, as confirmed by multivariate analyses. Furthermore, this work opens up the possibility of applying this method in more complex and relevant samples such as foodstuff, urine or blood.

Development of a rapid and sensitive immunosensor for the detection of bacteria.

The presence of Gram-positive bacteria in foodstuffs is a chronic worldwide problem. Here, we present a cheap and simple colorimetric method for the detection of Lactobacillus species (spp.) and Staphylococcus aureus (S. aureus) using gold nanoparticles (AuNP) modified with monoclonal anti-Gram-positive bacteria to produce an immune-sensor. Detection is based on the fact that antibody-conjugated AuNPs can readily identify Gram-positive bacteria through antibody-antigen recognition, which results in a color change of AuNPs upon aggregation. The detection limit was 105CFU/ml in pure culture for Lactobacillus spp. and 120CFU/ml in pure culture for S. aureus. The method was applied successfully for detection of bacteria in samples of sugar cane, and agreed well with values obtained using other methods. These results suggested that the detection system could be used for the quantitative analysis of Gram-positive bacteria and might be applied potentially by the food industry.

Design of Bioluminescence Sensor System for Rapid Detection of Bacteria in Samples without Cultivation

Based on the principle of ATP bioluminescent reaction, we design a portable bioluminescence sensor system to detect bacteria in samples rapidly, which included an optical sensing cell, a flow injection unit and a center processing unit. A fast ATP extraction technique was developed by using trichloro acetic acid as extraction reagent Experimental results showed that the intracellular ATP could be released from bacterial cells sufficiently within 5 min by TCA In the presence of Lucifer ace the reaction between ATP and lucifer5in would generate light and the luminescence intensity RLU was proportional to the amount of bacteria existed in the sample. The dynamic range of the sensor system is 10-107 CFU /ml. The linear regression coefficient was 0.976, and the detection limit was 10CFU /ml. The whole testing time needed was about 10 min. Compared with the plate count method, bacteria concentration in samples could be detected rapidly by using the portable sensor system without cultivation.

Incidence of bacterial transmission and transfusion reactions by blood components

Successful reduction of the risk of viral transmission via blood components has focused attention on the risk of transfusion-associated bacterial sepsis. The incidence of transfusion reactions due to bacteria is currently estimated at between 1 per 100,000 and 1 per 1,000,000 units in the case of packed red blood cells and between 1 per 900 and 1 per 100,000 units in the case of platelet concentrates. For autologous transfusion, only isolated case reports are available which do not permit a quantitative risk assessment. No reliable data on the risk of morbidity and mortality due to transfusion-associated bacterial infection are available for Germany at present. As platelet concentrates provide more favourable conditions for bacterial growth by virtue of being stored at room temperature, these blood components are thought to bear a considerably greater risk of bacterial contamination than red blood cells. The rate of contamination of platelet concentrates is cited at between 0.02% and 1.2%, depending on the production and bacterial culture techniques used, whereas the rate for packed red blood cells is between 0.1% and 0.2%. Risk reduction strategies include careful selection of blood donors, optimisation of donation and production techniques, and detection of bacteria in samples of blood components prior to transfusion. Also of importance for patient safety are quality assurance measures in the preparation for transfusion, in measures of patient monitoring, and investigation of transfusion reactions.

Bacterial contamination of blood components – incidence and significance for homologous and autologous transfusion Bakterielle Kontamination von Blutkomponenten – Inzidenz und Signifikanz für die allogene und autologe Transfusion

Abstract Successful reduction of the risk of viral transmission via blood components has emphasized the risk of transfusion-associated bacterial sepsis. The incidence of transfusion reactions due to bacteria is currently estimated to be between 1:100,000 and 1:1,000,000 units in the case of packed red blood cells and between 1:900 and 1:100,000 units in the case of platelet concentrates. For autologous transfusion, only isolated case reports are available which do not permit a quantitative risk assessment. At present, no reliable data on the risk of morbidity and mortality due to transfusion-associated bacterial infection are available for Germany. Since platelet concentrates, stored at room temperature, provide more favorable conditions for bacterial growth, these blood components are thought to bear a considerably greater risk of bacterial contamination than red blood cells. The rate of contamination of platelet concentrates is cited to be between 0.02 and 1.2%, depending on the production and bacterial culture techniques used, whereas the rate for packed red blood cells is between 0.1 and 0.2%. Risk reduction strategies include careful selection of blood donors, optimization of donation and production techniques, and detection of bacteria in samples of blood components prior to transfusion. Also important for patient safety are quality assurance measures in the preparation for transfusion, patient monitoring, and investigation of transfusion reactions.