

@article {2224,
	title = {{Sensitivity and performance characteristics of a direct PCR with stool samples in comparison to conventional techniques for diagnosis of Shigella and enteroinvasive Escherichia coli infection in children with acute diarrhoea in Calcutta, India}},
	journal = {J Med Microbiol},
	volume = {50},
	number = {8},
	year = {2001},
	pages = {667{\textendash}674},
	edition = {2001/08/02},
	abstract = {As the sensitivity of the conventional techniques for identifying Shigella spp. and enteroinvasive Escherichia coli (EIEC) causing dysentery cases is low, a PCR assay was evaluated in this study. Analytical sensitivity (2 x 10(2) cfu) of the PCR technique was obtained by artificially spiking negative stool samples with a standard strain of S. flexneri type 2, then determining the detection limit. Specificity (100\%) of the method was determined by testing a number of known Shigella and EIEC strains and organisms other than Shigella spp. A total of 300 stool samples collected from children with acute diarrhoea was plated on to two selective agar media after enrichment in Luria broth. Shigella spp. were isolated from 7.7\% (23 of 300) and EIEC from 1\% (3 of 300) patients. All enriched stool samples were subjected to PCR to amplify the target sequence of invasive plasmid antigen (ipa)H locus, a multicopy element found on the chromosome and invasion plasmid. The stool PCR was positive in 24 of the 26 culture-positive and in 22 culture-negative stools, thus detecting the presence of Shigella spp. or EIEC in 15.3\% (46 of 300) of diarrhoea cases. When an ial probe was used for colony hybridistion with enriched stool cultures blotted on to membranes, 9.6\% (29 of 300) of dysentery cases were identified as being caused by Shigella spp. or EIEC. Thus the sensitivity of enriched stool culture, colony hybridisation and enriched stool PCR was found to be 54\%, 60\% and 96\%, respectively, when each of the methods was compared to the total microbiologically confirmed cases of dysentery. It was also observed that only 38\% (48 of 126) of acute bloody dysentery cases actually had shigella or EIEC infection, as confirmed by laboratory methods. Moreover, this PCR assay could identify a number of untypable Shigella strains (Sh OUT), which would have remained undiagnosed had this assay not been used.},
	isbn = {0022-2615 (Print)
0022-2615 (Linking)},
	doi = {10.1099/0022-1317-50-8-667},
	author = {Dutta, S and Chatterjee, A and Dutta, P and Rajendran, K and Roy, S and Pramanik, K C and Bhattacharya, S K}
}
