LabMedica International
To view this issue in interactive digital magazine format visit www.LinkXpress.com
Breath Analysis Aims to Reduce Unnecessary Antibiotic Prescriptions number of multiresistant pathogens including Acinetobacter baumannii place a heavy burden on ventilator-associated pneumonia (VAP) patients in intensive care units (ICU), and it is critically important to differentiate between bacterial infection and colonization to avoid prescribing unnecessary antibiotics. Quantitative culture of lower respiratory tract (LRT) specimens, however, requires invasive procedures, however nowadays, volatile organic compounds (VOCs) have been studied in vitro and in vivo to identify pathogen-derived biomarkers. An efficient, fast, accurate, painless and affordable test has been developed that will assist doctors in prescribing antibiotics only when the treatment is absolutely necessary. Scientists at Zhejiang University (Hangzhou, China; www.zju.edu.cn) enrolled 20 patients with A. baumannii VAP (infection group), 20 ventilated
A
patients with LRT A. baumannii colonization (colonization group) and 20 ventilated patients with neurological disorders, but without pneumonia or A. baumannii colonization (control group). A clinical isolate of A. baumannii strains was used for the in vitro culture experiment. For breath sample collection and gas chromatography-mass spectrometry (GC-MS) analysis the team used a GC-MS, the QP2010 Plus (Shimadzu, Kyoto, Japan; www.shimadzu.com). The detected compounds corresponding to the peaks were identified by spectra matching with the above software and Mass Spectral Library (NIST 05). The retention time and mass spectrum similarities were used to identify the compounds of interest. Breath profiles could be visually differentiated between A. baumannii cultivation in vitro and culture medium, and among in vivo groups. In the in vitro
experiment, nine compounds of interest (2,5-dimethyl-pyrazine, 1-undecene, isopentyl 3-methylbutanoate, decanal, 1,3-naphthalenediol, longifolene, tetradecane, iminodibenzyl and 3-methyl-indene) in the headspace were found to be possible A. baumannii derivations. While there were eight target VOCs (1-undecene, nonanal, decanal, 2,6,10-trimethyl-dodecane, 5-methyl-5-propyl-nonane, longifolene, tetradecane and 2-butyl-1-octanol) exhibiting characteristics of A. baumannii VAP derivations. The authors concluded that the study mainly provides a proof of concept that the direct detection of exhaled A. baumannii-derived VOCs might be adopted for an early alert of the LRT bacterial presence in ventilated ICU patients and even different parasitic states (i.e. infection and colonization) of A. baumannii. The study was published on June 7, 2016, in the Journal of Breath Research.
Urinary ELISA Kit for Alzheimer’s Diagnosis lzheimer’s disease is the most common form of dementia, a general term for memory loss and other intellectual abilities serious enough to interfere with daily life and Alzheimer’s disease (AD) accounts for 60% to 80% of dementia cases. Early, accurate diagnosis of AD is beneficial for several reasons as beginning treatment early in the disease process may help preserve daily functioning for some time, even though the underlying Alzheimer’s process cannot be stopped or reversed. Scientists at the Capital Medical University (Beijing, China; www.csc.edu.cn) have developed noninvasive and simple method for early detection of AD, which will be extremely important for the diagnosis and prognosis of AD. They aimed to develop an enzyme-linked immunosorbent assay (ELISA) kit to detect urine Alzheimer-associated neuronal thread protein (AD7C-NTP), and to evaluate its clinical value for the diagnosis of AD. The scientists collected the first morning urine specimens of 121 AD patients and 118 age-matched
A
LINKXPRESS COM
LMI-11-16 171
LINKXPRESS COM
controls, and the urine AD7C-NTP levels were detected by the ELISA kit. The team synthesized immunogenic AD7C-NTP peptide fragments by the solid-phase method and used for immunizing mice or rabbits to generate anti-AD7C-NTP antibodies. The investigators reported that mouse and rabbit anti-AD7C-NTP antibody ELISA titer was found to be 1:8,000 and 1:32,000, respectively. A single band with a relative molecular mass of 41 kDa was found in human brain specimens by Western blot assay, which was identified as AD7C-NTP antibody. The urine AD7C-NTP concentration of the AD patients was higher than that of the age-matched controls, the sensitivity was 89.3% and the specificity was 84.7%. The authors concluded that they had successfully demonstrated that their newly developed urine AD7C-NTP ELISA kit has suggested potential for diagnosing AD in a Chinese population, suggesting it may be a useful diagnostic kit for detecting early AD. The study was published in the July 2016 issue of the Journal of Clinical Laboratory Analysis.
LMI-11-16 136