Rapid onsite detection of bacterial spores of biothreat importance by paper-based colorimetric method using erbium–pyrocatechol violet complex

• Published in: Applied microbiology and biotechnology 2016-01, Vol.100 (2), p.893-901
• Main Authors: Shivakiran, M. S, Venkataramana, M, Lakshmana Rao, P. V
• Format: Article
• Language: English
• Subjects: Acids; Analysis; Anthrax; Bacillus subtilis - isolation & purification; Bacteria; bacterial spores; Benzenesulfonates; Biological Warfare Agents; Biomedical and Life Sciences; Biotechnology; Chemical elements; Chemicals; Chloride; Colorimetry; Colorimetry - methods; Decontamination; Decontamination - methods; detection limit; Dyes; EDTA (chelating agent); Erbium; Europium; Health aspects; Ions; Laboratories; Life Sciences; Limit of Detection; Methods; Methods and Protocols; microbial detection; Microbial Genetics and Genomics; Microbiology; Neodymium; Nitrates; Onsite; Picolinic Acids; Polyvinyl alcohol; pyrocatechol; Reagents; Sensitivity and Specificity; Spores; Spores, Bacterial - isolation & purification; Studies; Terbium; Test methods
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-015-7151-7

Dipicolinic acid (DPA) is an important chemical marker for the detection of bacterial spores. In this study, complexes of lanthanide series elements such as erbium, europium, neodymium, and terbium were prepared with pyrocatechol violet and effectively immobilized the pyrocatechol violet (PV)–metal complex on a filter paper using polyvinyl alcohol. These filter paper strips were employed for the onsite detection of bacterial spores. The test filter papers were evaluated quantitatively with different concentrations of DPA and spores of various bacteria. Among the four lanthanide ions, erbium displayed better sensitivity than the other ions. The limit of detection of this test for DPA was 60 μM and 5 × 10⁶ spores. The effect of other non-spore-forming bacteria and interfering chemicals on the test strips was also evaluated. The non-spore-forming bacteria did not have considerable effect on the test strip whereas chemicals such as EDTA had significant effects on the test results. The present test is rapid and robust, capable of providing timely results for better judgement to save resources on unnecessary decontamination procedures during false alarms.