Application of an automated specimen search system installed in a transmission electron microscope for the detection of caliciviruses in clinical specimens.
To evaluate the performance of an automated specimen search system in the detection of caliciviruses such as Norwalk-like viruses and Sapporo-like viruses, a suitable negative staining method was developed and the viruses were examined using the system installed in a transmission electron microscope (TEM). Clear images of the viruses were obtained by staining with 2% uranyl acetate at pH 4.0 as compared with 2% phosphotungstic acid staining at any pH. When the image parameter of 30+/-6 nm for the diameter of a single virus-like particle of 2% uranyl-acetate-stained Norwalk-like virus was set on the automated specimen search system, 95% of the virus-like particles that were counted by the conventional TEM technique were detected. The system was used to detect Norwalk-like viruses in five semipurified stool samples in which Norwalk-like viruses had already been detected by reverse transcription-polymerase chain reaction assay and conventional electron microscopy. The positive detection rate for Norwalk-like viruses, which had been counted by the conventional technique, ranged from 56.2 to 77.9% using this system. Our findings indicate that the automated specimen search system installed in a TEM is suitable for the detection of caliciviruses in semipurified stool samples. The system is useful for clinical diagnosis without the need for operator intervention.
Utagawa
Etsuko T
ET
Department of Virology II, National Institute of Infectious Diseases, Toyama 1-23-1, Shinjuku-ku, Tokyo 162-8640, Japan. etu@nih.go.jp
Nakazawa
Eiko
E
Matsuo
Keiko
K
Oishi
Isao
I
Takeda
Naokazu
N
Miyamura
Tatsuo
T
D001331:Automation; D017250:Caliciviridae Infections / Q000473:pathology / Q000821:virology*; D005759:Gastroenteritis / Q000473:pathology / Q000821:virology*; D006801:Humans; D008854:Microscopy, Electron / Q000379:methods; D029322:Norovirus / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D009942:Organometallic Compounds; D010772:Phosphotungstic Acid; D029341:Sapovirus / Q000235:genetics / Q000302:isolation & purification* / Q000648:ultrastructure; D013194:Staining and Labeling / Q000379:methods
D009942:Organometallic Compounds; D010772:Phosphotungstic Acid; C005460:uranyl acetate