Routine laboratory testing may not detect non-O157 Shiga toxin-producing Escherichia coli (STEC) reliably. Active clinical, epidemiological, environmental health, and laboratory collaboration probably influence successful detection and study of non-O157 STEC infection. We summarized two outbreak investigations in which such coordinated efforts identified non-O157 STEC disease and led to effective control measures. Outbreak 1 involved illness associated with consuming unpasteurized apple cider from a local orchard. Public health personnel were notified by a local hospital; stool specimens from ill persons contained O111 STEC. Outbreak 2 involved bloody diarrhoea at a correctional facility. Public health personnel were notified by the facility infection control officer; O45 STEC was the implicated agent. These reports highlight the ability of non-O157 STEC to cause outbreaks and demonstrate that a coordinated effort by clinicians, infection-control practitioners, clinical diagnostic laboratorians, and public health personnel can lead to effective identification, investigation, and prevention of non-O157 STEC disease.
"Data from the Centers for Disease Control and Prevention indicate that STEC serogroups O26, O45, O103, O111, O121, and O145 cause the majority of cases of illness due to non-O157 STEC in the US and are important STEC serogroups in other countries, as well (Brooks et al., 2005; Johnson et al., 2006; Gyles, 2007). These STEC serogroups are referred to as the " top six " or " big six " serogroups, and major outbreaks of HC and HUS associated with these non-O157 STEC have been reported (Bettelheim, 2007; Mathusa et al., 2010; Schaffzin et al., 2012). Other STEC serogroups including O91 and O113 have also been linked to cases and outbreaks of HC and HUS and are important STEC in many countries (Paton et al., 1999; Johnson et al., 2006; Bettelheim, 2007; EFSA, 2009; Mellmann et al., 2009). "
[Show abstract][Hide abstract] ABSTRACT: Escherichia coli O157:H7 and certain non-O157 Shiga toxin-producing Escherichia coli (STEC) serogroups have emerged as important public health threats. The development of methods for rapid and reliable detection of this heterogeneous group of pathogens has been challenging. GeneDisc real-time PCR assays were evaluated for detection of the stx(1), stx(2), eae, and ehxA genes and a gene that identifies the O157 serogroup followed by a second GeneDisc assay targeting serogroup-specific genes of STEC O26, O45, O91, O103, O111, O113, O121, O145, and O157. The ability to detect the STEC serogroups in ground beef samples artificially inoculated at a level of ca. 2-20 CFU/25 g and subjected to enrichment in mTSB or buffered peptone water (BPW) was similar. Following enrichment, all inoculated ground beef samples showed amplification of the correct set of target genes carried by each strain. Samples inoculated with STEC serogroups O26, O45, O103, O111, O121, O145, and O157 were subjected to immunomagnetic separation (IMS), and isolation was achieved by plating onto Rainbow agar O157. Colonies were confirmed by PCR assays targeting stx(1), stx(2), eae, and serogroup-specific genes. Thus, this work demonstrated that GeneDisc assays are rapid, sensitive, and reliable and can be used for screening ground beef and potentially other foods for STEC serogroups that are important food-borne pathogens worldwide.
Frontiers in Cellular and Infection Microbiology 12/2012; 2:152. DOI:10.3389/fcimb.2012.00152 · 3.72 Impact Factor
"At the WC, identification of non-O157 STEC has increased from the two to three identified in 2000– 2001, i.e., prior to this study (data not shown), to 95 definitively identified in 2010, as a result of this enhanced STEC testing approach. Of note, utilization of this enhanced testing approach allowed for the identification of the serogroup and PFGE type as part of non-O157 STEC outbreak investigations that otherwise might not have been supported by laboratory data (Schaffzin et al., 2012). Our laboratory has also implemented real-time PCR methods to detect the top six non- O157 serogroups, which has improved timeliness of identification and outbreak investigation (data not shown). "
[Show abstract][Hide abstract] ABSTRACT: Abstract Non-O157 Shiga toxin-producing Escherichia coli (STEC) are emerging pathogens with the potential to cause serious illness and impact public health due to diagnostic challenges. Between 2005 and 2010, the Wadsworth Center (WC), the public health laboratory of the New York State (NYS) Department of Health, requested that Shiga toxin enzyme immunoassay (EIA)-positive stool enrichment broths and/or stool specimens be submitted by clinical and commercial reference laboratories testing NYS patient specimens. A total of 798 EIA-positive specimens were received for confirmation and serotyping, and additionally a subset of STEC was assessed for the presence of six virulence genes (stx1, stx2, eaeA, hlyA, nleA, and nleB) by real-time polymerase chain reaction. We confirmed 591 specimens as STEC, 164 (28%) as O157 STEC, and 427 (72%) as non-O157 STEC. Of the non-O157 STEC serogroups identified, over 70% were O103, O26, O111, O45, O121, or O145. During this time period, WC identified and characterized a total of 1282 STEC received as E. coli isolates, stool specimens, or EIA broths. Overall, the STEC testing identified 59% as O157 STEC and 41% as non-O157 STEC; however, out of 600 isolates submitted to the WC as E. coli cultures, 543 (90%) were identified as O157 STEC. This report summarizes a 6-year study utilizing enhanced STEC testing that resulted in increased identification and characterization of non-O157 STEC in NYS. Continued utilization of enhanced STEC testing may lead to effective and timely outbreak response and improve monitoring of trends in STEC disease epidemiology.
[Show abstract][Hide abstract] ABSTRACT: In summer 2009, the Utah Department of Health investigated an outbreak of Shiga-toxigenic Escherichia coli (STEC) O157:H7 (O157) illness associated with attendance at multiple rodeos.
Patients were interviewed regarding exposures during the week before illness onset. A ground beef traceback investigation was performed. Ground beef samples from patient homes and a grocery store were tested for STEC O157. Rodeo managers were interviewed regarding food vendors present and cattle used at the rodeos. Environmental samples were collected from rodeo grounds. Two-enzyme pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA) were performed on isolates.
Fourteen patients with primary STEC O157 illness were reported in this outbreak. Isolates from all patients were indistinguishable by PFGE. Isolates from nine patients had identical MLVA patterns (main outbreak strain), and five had minor differences. Thirteen (93%) patients reported ground beef consumption during the week before illness onset. Results of the ground beef traceback investigation and ground beef sampling were negative. Of 12 primary patients asked specifically about rodeo attendance, all reported having attended a rodeo during the week before illness onset; four rodeos were mentioned. All four rodeos had used bulls from the same cattle supplier. An isolate of STEC O157 identified from a dirt sample collected from the bullpens of one of the attended rodeos was indistinguishable by PFGE and MLVA from the main outbreak strain.
Recommendations were provided to rodeo management to keep livestock and manure separate from rodeo attendees. This is the first reported STEC O157 outbreak associated with attendance at multiple rodeos. Public health officials should be aware of the potential for rodeo-associated STEC illness.
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