Published Date: 2012-05-12 14:08:06
Subject: PRO/AH/EDR> E. coli EHEC - USA (13): (SC) O157
Archive Number: 20120512.1131024
E. COLI EHEC - USA (13): (SOUTH CAROLINA) O157
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Sat 12 May 2012
Source: Go Upstate [edited]
South Carolina state health inspectors are investigating an outbreak of _E. coli_ linked to a Spartanburg restaurant. Of the 11 suspected or confirmed cases associated with the same restaurant, 2 people were infected to a potentially serious level, said Adam Myrick, spokesman with the SC Department of Health and Environmental Control.
DHEC is continuing its "multi-faceted investigation" that includes reviewing restaurant menus, food samples and taking stool samples from those who have related symptoms who have eaten at the restaurant. Myrick wouldn't confirm the restaurant associated with the outbreak. Myrick said the cases were reported during the last week of April 2012 and the 1st week of May 2012. DHEC has since inspected the restaurant and does not have a "reason to believe the public is in danger at this time," Myrick said. "It's early in the investigation and we're piecing together information and talking to people," Myrick said. "We've looked at the facility and found no substantial problems, but again, it's early."
The agency issued an alert to local healthcare providers Friday afternoon, 11 May 2012, advising them of the symptoms associated with enterohemorrhagic _E. coli_ (EHEC), which include severe stomach cramps, diarrhea (sometimes bloody), vomiting and a mild fever. Myrick said the symptoms commonly last between 5 and 7 days, but children and elderly people are more susceptible to serious complications from the bacteria.
According to the CDC, EHEC is the most common outbreak of _E. coli_ reported in the USA annually with 265 000 reported illnesses. Of those, about 3600 people are hospitalized and 30 of those cases are fatal. DHEC recommends frequent handwashing, especially for children, since the bacteria can spread, or "shed," for several weeks after symptoms subside.
EHEC can be found in undercooked beef, raw milk, unpasteurized apple juice, contaminated water, lettuce, poultry, pork or lamb, according to the CDC.
[Byline: Lynne P. Shackleford]
Date: Fri 11 May 2012
Source: South Carolina Department of Health and Environmental Control [edited]
The South Carolina Department of Health and Environmental Control (DHEC) is requesting heightened surveillance for persons presenting with symptoms consistent with enterohemorrhagic _E. coli_ (EHEC), including diarrhea that is often bloody, hemolytic uremic syndrome (HUS) in children or thrombotic thrombocytopenia purpura in adults.
DHEC is investigating an outbreak of EHEC related to dining at a Spartanburg-area Mexican restaurant during the last week of April, 2012. Preliminary lab results indicate the _E. coli_ serotype being O157:H7. Of the 3 cases interviewed thus far, 2 reported the infection has progressed to hemolytic uremic syndrome (HUS), a severe condition associated with EHEC infection that can lead to kidney failure. Interviews with an additional 8 cases are in progress.
DHEC recommends a high index of suspicion for EHEC infection for patients presenting with EHEC symptoms and a history of dining at a Spartanburg-area Mexican restaurant near the end of April, 2012. Clinical syndromes associated with a Shiga toxin producing E. coli infection include:
-gastroenteritis with diarrhea and abdominal cramps (fever and bloody stools may or may not be present), and/or
-hemolytic uremic syndrome (HUS) with or without gastroenteritis, which typically develops a week after the onset of diarrhea. Hemolytic uremic syndrome (HUS) is characterized by the triad of acute onset of microangiopathic hemolytic anemia, renal injury, and low platelet count. Most cases of HUS occur after an acute gastrointestinal illness (usually diarrheal).
Management of STEC is typically supportive, as most patients recover within 5-7 days. Antibiotics for gastroenteritis are generally not recommended, as there have been reports of increased incidence of post-diarrheal HUS when antibiotics are used to manage EHEC infections. The CDC does not recommend the use of antibiotics for patients with suspected EHEC infections until complete diagnostic testing can be performed and STEC infection is ruled out. However, clinical decision making must be tailored to each individual patient. There may be indications for antibiotics in patients with severe intestinal inflammation if perforation is of concern.
[ProMED awaits for additional information regarding the scope of this cluster of EHEC as well as more information regarding the search of its vehicle of transmission.
Regarding the use of antimicrobials in EHEC infection, Since Wong, et al (1) reported a relative risk of the development of HUS in _E. coli_ O157 infection of 17.3 (95 percent confidence interval 2.2 to 137), it has generally been thought that antimicrobial agents increase HUS risk. In this study, trimethoprim-sulfamethoxazole and beta-lactam drugs were those most linked to HUS. Whether other antimicrobial agents would likewise be linked to HUS, if the same effect would occur in adults, if non-O157 strains would behave similarly and what the mechanism of the effect were not clearly known. Overall, trimethoprim-sulfamethoxazole (also referred to as cotrimoxazole) and fluoroquinolones seemed to be the prime offenders, both not uncommonly used empirically for perceived bacterial enteritis.
Lee and Stein (2) suggest that imipenem decreased Shiga toxin release in vitro as compared to untreated control cultures and to amikacin, norfloxicin, or trimethoprim/sulfamethoxazole, which all caused increased toxin release. The Shiga toxin genes reside on a lambda-like bacteriophage genome integrated into the bacterial chromosome. Different EHEC strains contain various numbers of these phages displaying much diversity and some being defective (3). In particular, fluoroquinolones induce high level expression of previously silent bacteriophage genes with coexpression of the toxin genes.
A number of studies have studied Shiga toxin production and or release using a variety of antimicrobial agents at subinhibitory and/or suprainhibitory concentrations using a variety of markers for toxin. These include direct immunologic measurement, cytotoxicity assays and enzyme reporters. It appears that imipenem (4) and rifaximin (5) do not induce toxin production or phage-mediated cell lysis suggesting that these agents may not increase the risk of HUS and might be useful in management. Ochoa, et al (5) found that fluoroquinolones induced Shiga toxin induction much more commonly in O157 as compared to non-O157 strains but Lee and Stein (2) did not.
As mentioned in the official posting above, antimicrobial therapy could well be suggested in EHEC infection if the possibility of overt peritonitis is considered. In this circumstance, a carbapenem such as imipenem may be a reasonable choice because it appears not to result in increased Shiga toxin production.
1. Wong CS, Jelacic S, Habeeb RL, et al: The risk of the hemolytic-uremic syndrome after antibiotic treatment of _Escherichia coli_ O157:H7 infections. N Engl J Med 2000; 342(26): 6; available at http://www.nejm.org/doi/full/10.1056/NEJM200006293422601.
2. Lee AH, Stein BD :Antimicrobials effective for inhibition of enterohemorrhagic _E. coli_ strains O26, O111, and O157 and their effects on Shiga toxin releases. J Microbiol Biotechnol 2009;19: 1238-43.
3. Hayashi T, Makino K, Ohnishi M, et al: Complete genome of sequence of enterohemorrhagic _Escherichia coli_ O157:H7 and genomic comparison with a laboratory strain K-12. DNA Res. 2001; 8(1): 11-22; available at http://dnaresearch.oxfordjournals.org/content/8/1/11.long.
4. Takahashi K, Narita K, Kato Y, et al: Low-level release of Shiga-like toxin (verocytotoxin) and endotoxin from enterohemorrhagic _Escherichia coli_ treated with imipenem. Antimicrob Ag Chemotherap 1997; 41(10): 2295-6; available at http://aac.asm.org/cgi/reprint/41/10/2295?view=long&pmid=9333067.
5. Ochoa TJ, Chen J, Walker CM, et al: Rifaximin does not induce toxin production or phage-mediated lysis of Shiga toxin-producing _Escherichia coli_. Antimicrob Ag Chemotherap 2007; 51(8): 2837-41; available at http://aac.asm.org/cgi/content/full/51/8/2837?view=long&pmid=17526759.
- Mod. LL]