A study on detecting and identifying enteric pathogens with PCR.
OBJECTIVE
To develop a rapid and definite diagnostic test of bacterial enteritis caused by pathogenic enterobacteria, the most frequent etiologic agent of infectious enteritis in the world.


METHODS
A set of conventional PCR assays were applied to detect and identify salmonella, shigella, and E. coli O157:H7 directly from pure culture and fecal samples. The general primers of pathogenic enterobacteria were located on the uidA gene, which were found not only in E. coli nuclear acid, but also in shigella and salmonella genes. Shigella primer was from ipaH gene whose coded invasive plasmid relative antigen existed both in plasmid and in genome. The primers of salmonella were designed from the 16SrRNA sequence. The primer of E. coli O157:H7 was taken from eaeA gene. Five random primers were selected for RAPD. The detection system included common PCR, semi-nested PCR and RAPD.


RESULTS
This method was more sensitive, specific and efficient and its processing was rapid and simple. For example, the method could be used to specifically detect and identify salmonella, shigella, and E. coli O157:H7, and its sensitivity ranged from 3 to 50 CFU, and its detection time was 4 hours.


CONCLUSIONS
This PCR method, therefore, can serve as a routine and practical protocol for detecting and identifying pathogenic microorganisms from clinical samples.
Li
Jun-Wen
JW
Department of Environment and Health, Institute of Health and Environmental Medicine, 1 Da Li Road, Tianjin 300050, China. junwenli@eyou.com
Shi
Xiu-Quan
XQ
Chao
Fu-Huan
FH
Wang
Xin-Wei
XW
Zheng
Jin-Lai
JL
Song
Nong
N
D017931:DNA Primers; D004269:DNA, Bacterial / Q000032:analysis*; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D006801:Humans; D016133:Polymerase Chain Reaction; D012485:Salmonella typhi / Q000302:isolation & purification*; D012680:Sensitivity and Specificity; D012763:Shigella flexneri / Q000302:isolation & purification*
D017931:DNA Primers; D004269:DNA, Bacterial