Multimodal approach for diagnosis of bacterial etiology in brain abscess

Anamika Bajpai; Kashi Nath Prasad; Priyanka Mishra; Rakesh Kumar Gupta; Aloukick K Singh; Bal Krishna Ojha

doi:10.1016/j.mri.2014.02.015

Multimodal approach for diagnosis of bacterial etiology in brain abscess

Magn Reson Imaging. 2014 Jun;32(5):491-6. doi: 10.1016/j.mri.2014.02.015. Epub 2014 Feb 18.

Authors

Anamika Bajpai¹, Kashi Nath Prasad², Priyanka Mishra¹, Rakesh Kumar Gupta³, Aloukick K Singh¹, Bal Krishna Ojha⁴

Affiliations

¹ Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences.
² Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences. Electronic address: kashinprasad@gmail.com.
³ Department of Radiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences.
⁴ Department of Neurosurgery, King George medical College, Lucknow, India.

PMID: 24661636
DOI: 10.1016/j.mri.2014.02.015

Abstract

Background and purpose: Proton magnetic resonance spectroscopy (PMRS) has high sensitivity and specificity for the detection of pyogenic brain abscess and the categorization of bacteria. But the metabolite patterns failed to evaluate the etiology of disease when the culture results are sterile. The aim of the present study is to compare the multimodality techniques viz., conventional culture, MR spectroscopy and 16S rRNA PCR and sequencing for rapid diagnosis of etiology in brain abscess and evaluate the PMRS in culture sterile samples and also demonstrate the sensitivity and specificity of these techniques.

Methods: Thirty five patients underwent MRI on a 3T MRI and in-vivo PMRS for the diagnosis and evaluation of various resonances of metabolites such as lipid (LIP), lactate (LAC), acetate (AC), amino acid (AC), succinate (SUC). Pus was collected for identification of etiologic agents by culture and molecular method.

Results: In 35 samples, metabolite patterns were as follows: LIP/LAC/AA, n=17, LIP/LAC/AA/SUC with or without AC, n=17 and LIP/LAC/AA/AC, n=1. Culture showed bacterial growth in 22 samples (18 aerobic/facultative anaerobic, 9 anaerobic) whereas molecular method was detected 26 aerobic/facultative anaerobic, 13 anaerobic, 4 microaerophilic bacteria. Among the 13 sterile samples, molecular method detected 16 microorganisms along with 3 mixed infections and PMRS recognized metabolite patterns as LIP/LAC/AA, n= 5 and LIP/LAC/AA/SUC with or without AC, n=8. The sensitivity of in-vivo PMRS in sterile samples was 100% and 75%, and specificity was 75% and 100% for aerobic and anaerobic organisms respectively.

Conclusion: Based on metabolite resonances, PMRS can detect slow growing and fastidious organisms and classify them into aerobic and anaerobic bacteria which are difficult to culture by conventional method. It can categorize microorganisms even in culture sterile samples with rational sensitivity and specificity which may allow early choice of targeted therapy.

Keywords: Bacterial culture; Brain abscess; Molecular technique; PMRS.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Bacteria / genetics
Bacteria / isolation & purification*
Biomarkers / analysis
Brain Abscess / diagnosis*
Brain Abscess / microbiology*
Female
Humans
Magnetic Resonance Imaging / methods*
Male
Molecular Diagnostic Techniques / methods*
Polymerase Chain Reaction / methods*
Proton Magnetic Resonance Spectroscopy / methods*
Reproducibility of Results
Sensitivity and Specificity
Sequence Analysis, DNA / methods

Substances

Biomarkers