Detection of pneumolysin in sputum.
Western blot detection of the species-specific pneumococcal product, pneumolysin (SPN), was shown to be almost as sensitive as PCR for the non-cultural detection of pneumococci in 27 Streptococcus pneumoniae culture-positive sputa from patients stated to have chest infections. Both techniques were considerably more sensitive than counter-current immuno-electrophoresis for pneumococcal capsular polysaccharide antigens (CPS-CIE) on the same specimens. Sensitivities for PCR, SPN-immunoblotting and CPS-CIE were 100%, 85% and 67%, respectively. In 11 S. pneumoniae culture-negative sputa taken from patients receiving antibiotics, but with proven recent pneumococcal infection, PCR and SPN-blot were positive in six (in two of which CPS-CIE was also positive), PCR alone was positive in one and SPN-blot alone was positive in one. In 11 S. pneumoniae culture-negative samples from patients not receiving antibiotics, all three tests were negative in eight, PCR was positive in three (in one of which CPS-CIE was also positive), but SPN-blot was negative in all 11. In 16 S. pneumoniae culture-negative samples from patients receiving antibiotics and with no known recent pneumococcal infections, one or more non-cultural test was positive in 11. Although further evaluation is required to assess the significance of pneumolysin detection in relation to carriage and infection and to devise a more suitable test format, these preliminary studies suggest that pneumolysin detection is a promising new approach to the non-cultural diagnosis of pneumococcal chest infection.
Wheeler
Janice
J
Newcastle Regional Public Health Laboratory, Westgate Road, Newcastle upon Tyne NE4 6BE.
Freeman
Roger
R
Newcastle Regional Public Health Laboratory, Westgate Road, Newcastle upon Tyne NE4 6BE.
Steward
Michael
M
Novocastra Laboratories Ltd, Balliol Business Park West, Benton Lane, Newcastle upon Tyne NE 12 8EW.
Henderson
Kirstine
K
Novocastra Laboratories Ltd, Balliol Business Park West, Benton Lane, Newcastle upon Tyne NE 12 8EW.
Lee
Maureen J S
MJS
Novocastra Laboratories Ltd, Balliol Business Park West, Benton Lane, Newcastle upon Tyne NE 12 8EW.
Piggott
Nigel H
NH
Novocastra Laboratories Ltd, Balliol Business Park West, Benton Lane, Newcastle upon Tyne NE 12 8EW.
Eltringham
Gary J A
GJA
Newcastle Regional Public Health Laboratory, Westgate Road, Newcastle upon Tyne NE4 6BE.
Galloway
Angela
A
Newcastle Regional Public Health Laboratory, Westgate Road, Newcastle upon Tyne NE4 6BE.
D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins; D015153:Blotting, Western / Q000379:methods; D003378:Counterimmunoelectrophoresis; D006801:Humans; D011008:Pneumococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D016133:Polymerase Chain Reaction / Q000379:methods; D011135:Polysaccharides, Bacterial / Q000032:analysis; D012141:Respiratory Tract Infections / Q000175:diagnosis* / Q000382:microbiology; D012680:Sensitivity and Specificity; D013183:Sputum / Q000737:chemistry* / Q000382:microbiology; D013296:Streptococcus pneumoniae / Q000302:isolation & purification* / Q000378:metabolism; D013301:Streptolysins / Q000032:analysis*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial; D013301:Streptolysins; C032290:plY protein, Streptococcus pneumoniae