Using an ATR-FTIR Technique to Detect Pathogens in Patients with Urinary Tract Infections: A Pilot Study

Abstract

Urinary tract infections (UTIs) are a leading hospital-acquired infection. Although timely detection of causative pathogens of UTIs is important, rapid and accurate measures assisting UTI diagnosis and bacterial determination are poorly developed. By reading infrared spectra of urine samples, Fourier-transform infrared spectroscopy (FTIR) may help detect urine compounds, but its role in UTI diagnosis remains uncertain. In this pilot study, we proposed a characterization method in attenuated total reflection (ATR)-FTIR spectra to evaluate urine samples and assessed the correlation between ATR-FTIR patterns, UTI diagnosis, and causative pathogens. We enrolled patients with a catheter-associated UTI in a subacute-care unit and non-UTI controls (total n = 18), and used urine culture to confirm the causative pathogens of the UTIs. In the ATR-FTIR analysis, the spectral variation between the UTI group and non-UTI, as well as that between various pathogens, was found in a range of 1800–900 cm−1, referring to the presence of specific constituents of the bacterial cell wall. The results indicated that the relative ratios between different area zones of vibration, as well as multivariate analysis, can be used as a clue to discriminate between UTI and non-UTI, as well as different causative pathogens of UTIs. This warrants a further large-scale study to validate the findings of this pilot research.

Analysis of Carbon Materials with Infrared Photoacoustic Spectroscopy

“…The spectra of the carbon materials were measured with an IR-PAS system, in which the PAS accessory attached to a microphone detector (model number PAC300) was provided by MTEC Photoacoustic, Inc. This PAS part was coupled to a Fourier transform infrared (FTIR) spectrometer (ABB FTLA2000-104, Quebec, Canada) . To reduce interference from environmental gases, the FTIR spectrometer was flushed out with gaseous nitrogen.…”

“…This PAS part was coupled to a Fourier transform infrared (FTIR) spectrometer (ABB FTLA2000-104, Quebec, Canada). 30 To reduce interference from environmental gases, the FTIR spectrometer was flushed out with gaseous nitrogen. Meanwhile, the PAS cell was purged with helium gas to enhance the sensitivity of the signal; by this means, the flow rate of He was regulated below 5 cc/s to avoid blowing sample powders into the detector.…”

Valorization of Spent Brewer’s Yeast Bioactive Components via an Optimized Ultrasonication Process

“…The SBY sample presented the characteristic bands for yeasts: the large band in the region 3200-3500 cm −1 corresponded to -OH and -NH groups involved in H-bonds [32], 3000-2800 cm −1 corresponded to the -CH 2 and -CH 3 groups from aliphatic chains such as lipids [32][33][34], 1622 and 1518 cm −1 corresponded to amide I and amide II in proteins and chitin, respectively, and 1022 cm −1 corresponded to polysaccharides, mainly β-glucans [32][33][34][35][36]. Other bands are 1585 cm −1 and 1346 cm −1 , which most probably come from the N-acetylglucosamine residues in mannoproteins and chitin [34,[36][37][38]; 1452 cm −1 , which was previously assigned to -CH 2 and -CH 3 in aliphatic compounds; side chains of amino acids; 1398 cm −1 , previously assigned to carboxylic groups and CH 2 wagging in lipids and β-(1,3)-glucans [32]; and 1234 cm −1 , suggested to reflect phosphate groups present in nucleic acids, phospholipids and/or proteins [35,39,40]. Amide III also has a contribution in the region 1350-1250 cm −1 .…”

Diabetes Monitoring through Urine Analysis Using ATR-FTIR Spectroscopy and Machine Learning

“…Recently, several methods have been introduced for urine analysis, and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy is an effective option due to its sensitive and non-destructive technique. ATR-FTIR spectroscopy is capable of extracting intricate biochemical information from the vibrational energy inherent in chemical bonds found within biomolecules, such as lipids, nucleic acids, proteins, and carbohydrates when applied to liquid matrices [13][14][15]. This analytical technique ensures the detailed quantitative assessment of complicated biochemical samples, thus enabling the identification of the concentration of specific molecules [16].…”