Volume 13, Number 2—February 2007
Dispatch
Surveillance for Shiga Toxin–producing Escherichia coli, Michigan, 2001–2005
Table 1
Evaluation of shiga toxin–producing Escherichia coli detection methods, Michigan, 2001–2005*
Detection method | Stool samples | Routine STEC surveillance†,
no. (%) | Enhanced STEC surveillance,
no. (%) | |||
---|---|---|---|---|---|---|
2001 | 2002 | 2003 | 2004 | 2005 | ||
Culture and PCR‡ for stx genes of suspect NSF E. coli | Total | 327 | 337 | 249 | 317 | 286 |
O157 | 85 (26) | 94 (28) | 63 (25) | 58 (18) | 56 (20) | |
Non-O157 | 2 (0.6) | 0 (0) | 0 (0) | 2 (0.6) | 1 (0.3) | |
EIA of bloody or suspect samples | Total | N/A | N/A | 209 | 141 | 73 |
O157 | 4 | 11 | 11 (5) | 7 (5) | 6 (8) | |
Non-O157 | 4 | 9 | 4 (2) | 7 (5) | 7 (10) | |
EIA of all samples | Total | N/A | N/A | N/A | 1,405 | 1,021 |
O157 | N/A | N/A | N/A | 5 (0.4) | 1 (0.1) | |
Non-O157 | N/A | N/A | N/A | 1 (0.07) | 0 (0) |
*STEC, Shiga toxin–producing Escherichia coli; NSF, non-sorbitol–fermenting; EIA, enzyme immunoassay.
†In 2001 and 2002, EIA of bloody stools was performed by 2 large clinical laboratories in Michigan and was not part of the enhanced STEC surveillance system at the Michigan Department of Community Health. Therefore, the total number of EIAs performed is not known; the total number of EIA s submitted as positive for Stx is provided by serotype.
‡PCR for stx1,2 genes was not initiated at the Michigan Department of Community Health until 2002. Before 2002, a DNA probe (Digene Signal Kit, Digene Diagnostic, Inc., Silver Spring, MD, USA) was used to detect STEC.