Detection Of Bacteria In Urine Research Articles

A rapid colorimetric sensing methodology for urinary tract bacterial pathogens as a point-of-care approach using natural anthocyanin loaded nanosilver

Various commercial diagnostic kits have been used to detect uropathogens. However, non-intensive, sensitive, and instantaneous detection of bacteria in urine is still at its infancy. Herein, a facile attempt was carried out to detect the most common uropathogens using anthocyanin-loaded silver nanoparticles as the indicator. The significance of the current research was to apply the crucial sensing ability of eggplant peel anthocyanin to detect each pathogen by exhibiting discrete colors, based on pH of the urine sample. The novelty of this study was the ability of a single indicator compound to distinctively differentiate multiple uropathogens, as monocultures or consortia, with accurate chromacity, simultaneously and instantaneously. Anthocyanin (AC) from eggplant (Solanum melongena) peels acted as a pH responsive sensor in the prepared indicator solution. The solution was used to sense three each of Gram-positive and Gram-negative uropathogens, as both monoculture and consortium. AC was loaded onto silver nanoparticles (AgNP) to stabilize the pigment. An evident color change due to the function of AC was considered as the end-point of detection. The optimized conditions for the study were obtained as: 50 μL indicator solution, 105CFU.mL−1 inoculum, and instantaneous sensing time. Deprotonation and protonation of AC due to ammonia and acids, evolved from the microbes, subsequently varied the pH level in the medium. These resulted in the generation of colors as hues of yellow, orange, green and blue and semi-quantitatively represented using average RGB values and delta E analysis obtained after the indicator solution was added to 24 h bacterial growth. In conclusion, the proposed solution can be a potential alternative to the conventional diagnostic tools as a specific, sensitive, rapid, precise and affordable indicator for point-of-care diagnosis of urinary tract infection.

Combined negative dielectrophoresis with a flexible SERS platform as a novel strategy for rapid detection and identification of bacteria.

Surface-enhanced Raman spectroscopy (SERS) is a vibrational method successfully applied in analytical chemistry, molecular biology and medical diagnostics. In this article, we demonstrate the combination of the negative dielectrophoretic (nDEP) phenomenon and a flexible surface-enhanced Raman platform for quick isolation (3min), concentration and label-free identification of bacteria. The platform ensures a strong enhancement factor, high stability and reproducibility for the SERS response of analyzed samples. By introducing radial dielectrophoretic forces directed at the SERS platform, we can efficiently execute bacterial cell separation, concentration and deposition onto the SERS-active surface, which simultaneously works as a counter electrode and thus enables such hybrid DEP-SERS device vibration-based detection. Additionally, we show the ability of our DEP-SERS system to perform rapid, cultivation-free, direct detection of bacteria in urine and apple juice samples. The device provides new opportunities for the detection of pathogens.

Evaluation of a Novel Light Scattering Methodology for the Detection of Pathogenic Bacteria in Urine.

Urine culture, the gold standard for detecting and identifying bacteria in urine, is one of the highest volume tests in many microbiology laboratories. The inability to accurately predict which patients would benefit from culture leads not only to monopolization of laboratory resources, but also to unnecessary antimicrobial exposure as patients receive empirical treatment for suspected or presumed urinary tract infections (UTI) while awaiting culture results. A common approach to decrease unnecessary urine culture is screening samples using urinalysis (UA) parameters to determine those that should proceed to culture (reflex). In this study, we compared the performance of a novel uropathogen detection method to urinalysis for purposes of UTI screening. Urine specimens submitted for culture (n = 194) were evaluated by urinalysis and a novel light scattering device (BacterioScan 216Dx UTI System) capable of detecting the presence of bacteria in urine. Sensitivity and specificity for prediction of a positive urine culture by UA and 216Dx were determined relative to urine culture results. A positive urine culture was defined as growth in culture of one or two uropathogens at concentrations of ≥50,000 CFU/mL. 194 urine samples were evaluated by UA, 216Dx, and urine culture. The 216Dx demonstrated a 100% [95%CI: 88.43%-100.0%] sensitivity and 81.71% [95%CI: 74.93%-87.30%] specificity for the detection of bacteriuria, vs UA with a sensitivity of 86.67% [95%CI 69.28%-96.24%] and specificity of 71.95% [95%CI: 64.41%-78.68%] when compared to urine culture (diagnostic reference method). BacterioScan allows for an alternative method of screening with satisfactory sensitivity and improved specificity that may facilitate a reduction of unnecessary cultures. Additional studies are required to determine if a concomitant decrease in inappropriate antibiotic use can be realized with the 216Dx technology.

Sensitivity of point-of-care testing C reactive protein and procalcitonin to diagnose urinary tract infections in Dutch nursing homes: PROGRESS study protocol

IntroductionSuspected urinary tract infection (UTI) ranks among the most common reasons for antibiotic use in nursing homes. However, diagnosing UTI in this setting is challenging because UTI often presents with...

Rapid identification of urinary tract infections based on ultrasensitive bacteria detection using volumetric bar-chart chip

Rapid and accurate detection of bacteria in urine is the key to improving the diagnostic efficiency of urinary tract infections. In this work, a microfluidic device was developed for visually quantifying pathogenic bacteria in urine without any external equipment. This pioneering strategy has high sensitivity, selectivity and accuracy for rapid detection of Escherichia coli and Staphylococcus aureus simultaneously. It not only shortens the entire test time to 1.5 h, but also successfully reduces the detection limit to 1 CFU/mL, which significantly improves the early diagnosis rate of bacterial infections. Due to the strong affinity of aptamers to target bacteria and the amplification of signals by platinum nanoparticle probes (Pt NP probes) with high catalytic activity, the sensitivity of the device has reached 1 CFU/mL. Moreover, the detection results of UTIs in clinical specimens were consistent with the gold standard, which not only verifies the good accuracy and reliability of the method in such a complex liquid environment, but also implies that the application of the device is paving a new path for biomarker detection and disease diagnosis.

Biomimetic Bacterial Identification Platform Based on Thermal Transport Analysis Through Surface Imprinted Polymers: From Proof of Principle to Proof of Application

Accurate and sensitive detection of bacteria is crucial in medicine for diagnosis and effective treatment of infectious diseases. Current state‐of‐the art methods consist of either traditional time consuming microbiological analysis or rapid, sensitive molecular techniques that require expensive readout equipment. In previous work, the authors of this paper combined synthetic bacteria receptors, so‐called surface imprinted polymers (SIPs), with a novel thermal biosensor readout methodology for the detection of bacteria in urine. In this follow‐up study, the potential of the method for application in urinary tract infection (UTI) diagnosis is further studied. The reproducibility of the method is assessed by expanding the study and analyzing the sensor's performance in urine samples obtained from four healthy adults. The samples are spiked with increasing concentrations of Escherichia coli to obtain different dose‐response curves. The results of this study show that the method is reproducible over the studied population and variables such as age, gender and osmolality do not seem to influence the test. All results fall within the previously established dynamic range of 104–105 bacteria mL−1 which fits well within the diagnostic window of classical microbiological UTI tests. Further tests conducted on a urine sample 24 h after spiking illustrate the problem with traditional microbiology tests as the sensor response has significantly decreased due to the presence of a significant amount of dead bacteria in the day‐old sample. These results confirm that fast, point‐of‐care analysis of fresh urine samples is advantageous over classic laborious techniques in terms of accurate diagnosis.

Microfluidic Capillaric Circuit for Rapid and Facile Bacteria Detection.

Urinary tract infections (UTI) are one of the most common bacterial infections and would greatly benefit from a rapid point-of-care diagnostic test. Although significant progress has been made in developing microfluidic systems for nucleic acid and whole bacteria immunoassay tests, their practical application is limited by complex protocols, bulky peripherals, and slow operation. Here we present a microfluidic capillaric circuit (CC) optimized for rapid and automated detection of bacteria in urine. Molds for CCs were constructed using previously established design rules, then 3D-printed and replicated into poly(dimethylsiloxane). CCs autonomously and sequentially performed all liquid delivery steps required for the assay. For efficient bacteria capture, on-the-spot packing of antibody-functionalized microbeads was completed in <20 s followed by autonomous sequential delivery of 100 μL of bacteria sample, biotinylated detection antibodies, fluorescent streptavidin conjugate, and wash buffer for a total volume ≈115 μL. The assay was completed in <7 min. Fluorescence images of the microbead column revealed captured bacteria as bright spots that were easily counted manually or using an automated script for user-independent assay readout. The limit of detection of E. coli in synthetic urine was 1.2 × 102 colony-forming-units per mL (CFU/mL), which is well below the clinical diagnostic criterion (>105 CFU/mL) for UTI. The self-powered, peripheral-free CC presented here has potential for use in rapid point-of-care UTI screening.

Selective detection of bacteria in urine with a long-range surface plasmon waveguide biosensor.

Experimentation demonstrates long-range surface plasmon polariton waveguides as a useful biosensor to selectively detect gram negative or gram positive bacteria in human urine having a low concentration of constituents. The biosensor can detect bacteria at concentrations of 10(5) CFU/ml, the internationally recommended threshold for diagnostic of urinary tract infection. Using a negative control urine solution of bacterial concentration 1000☓ higher than the targeted bacteria, we obtain a ratio of 5.4 for the positive to negative signals.

Detection of bacteria in urine using dip-slides (1). Possible occurrence of false-negative results when dip-slides are used for urine containing antibacterial agents

Dip-slides are used as semiquantitative microbial sampling devices that are simple to use in routine testing of urine to detect the presence of bacteria, and are recommended for use in "Standard evaluation of drug efficacy in UTI". Bacterial growth on currently available dip-slides, however, may conceivably be influenced by the presence of antibacterial agents in urine. We studied clinical performance of, and effects of antibacterial agents on, such dip-slides, using two types of dip-slides, URICULTE and DIASLIDE, both of which are newly developed urine culture devices. The quantitative conventional culture method was also used as the control. 1. When single species of bacteria are present in urine specimens of patients, results obtained using URICULTE and DIASLIDE agreed very well, and they, in turn agreed well with results obtained using the quantitative, conventional culture method, also. 2. When urine specimens were spiked with Gram-negative rods and Gram-positive cocci together, URICULTE fail to provide quantitative results because colonies were not well separated and confluent growth often resulted because of a large sample volume this device employs. DIASLIDE which used a smaller amount of sample, on the other hand, provided quantitative results with adequate separation of colonies. 3. When three antibacterial agents were added to urine specimens that were spiked with bacteria, DIASLIDE produced significantly higher numbers of colonies than URICULTE. The difference probably are due to the difference in volumes of specimens used in the two devices, the former device employs approximately 1/100 as much volume of specimen as the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Identifying Bacteria in Human Urine: Current Practice and the Potential for Rapid, Near-Patient Diagnosis by Sensing Volatile Organic Compounds

Urinary tract infection (UTI) represents a significant burden for the National Health Service. Extensive research has been directed towards rapid detection of UTI in the last thirty years. A wide range of microbiological and chemical techniques are now available to identify and quantify bacteria in urine. However, there is a clear and present need for near, rapid, sensitive, reliable analytical methods, preferably with low-running costs, that could allow early detection of UTI and other diseases in urine. Here we review the "state of the art" of current practice for the detection of bacteria in urine and describe the advantages of the recent "e-nose" technology as a potential tool for rapid, near-patient diagnosis of UTI, by sensing volatile organic compounds (VOCs).

Electrochemical detection of viable bacteria in urine and antibiotic selection

An electrode system consisting of a basal-plane pyrolytic graphite (BPG) electrode and a porous nitrocellulose membrane filter to trap bacteria was used for the detection of bacteria in urine. The peak current of a cyclic voltammogram increased with increasing initial cell concentration of Escherichia coli in urine. Urine containing from 5 × 10 2 to 5 × 10 5 cells ml −1 was measured with this system. The susceptibility of bacteria to various antibiotics was also determined from the peak current. The minimum inhibitory concentration values obtained by the electrochemical method were in good agreement with those obtained by the conventional method.

Reverse-flow apparatus for enhanced colorimetric detection of bacteriuria.

The reverse-flow apparatus is a new device for enhancing the detection of bacteria in urine. Bacteria are trapped onto a customized filter, and the pigments, crystals, and other interfering substances in the urine pass through the filter and are discarded. The bacteria are backflushed and are recovered as a concentrate, and the concentrate is then processed through the previously described colorimetric bacteriuria detection device. A total of 1,000 urine samples were obtained from randomly selected patients and were cultured on agar. Upon enumeration of the colonies, 160 urine samples were shown to contain more than 10(5) CFU/ml. In the bacteriuria detection device, 150 urine samples could not be processed (pigmenters and cloggers), and of the 850 urine samples processed, 127 were culture positive for 10(5) CFU/ml or greater, and 150 urine samples contained between 10(4) and 10(5) CFU/ml. At 10(5) CFU/ml, there were 140 false-positives and 14 false-negatives. When duplicate urine samples were processed through and concentrated by our new reverse-flow apparatus, all samples, including the above pigmenters and cloggers, could be tested in the bacteriuria detection device. The 150 unprocessable samples described above yielded 33 additional bacteria-positive urines, 23 at the 10(5)-CFU/ml cutoff and 10 at the 10(4)-to-10(5)-CFU/ml cutoff. There were 105 false-positives at 10(5) CFU/ml and only 2 false-negatives at the same level of bacteria. At 10(4) to 10(5) CFU/ml there was only 1% false-positive and 4% false-negative. The reverse-flow apparatus allows greater specificity and sensitivity in the rapid bacteriuria test. Urine containing 10(4) CFU/ml or more can now be detected with a 96% sensitivity in a total processing time of less than 2 min.

Rapid Detection of Bacteria in Urine

Rapid Detection of Bacteria in Urine