Incidence and Virulence Determinants of Verocytotoxin-Producing Escherichia coli Infections in the Brussels-Capital Region, Belgium, in 2008–2010

Abstract

hThe incidence of verocytotoxin-producing Escherichia coli (VTEC) was investigated by PCR in all human stools from Universitair Ziekenhuis Brussel (UZB) and in selected stools from six other hospital laboratories in the Brussels-Capital Region, Belgium, collected between April 2008 and October 2010. The stools selected to be included in this study were those from patients with hemolytic-uremic syndrome (HUS), patients with a history of bloody diarrhea, patients linked to clusters of diarrhea, children up to the age of 6 years, and stools containing macroscopic blood. Verocytotoxin genes (vtx) were detected significantly more frequently in stools from patients with the selected conditions (2.04%) than in unselected stools from UZB (1.20%) (P ‫؍‬ 0.001). VTEC was detected most frequently in patients with HUS (35.3%), a history of bloody diarrhea (5.15%), or stools containing macroscopic blood (1.85%). Stools from patients up to the age of 17 years were significantly more frequently vtx positive than those from adult patients between the ages of 18 and 65 years (P ‫؍‬ 0.022). Although stools from patients older than 65 years were also more frequently positive for vtx than those from patients between 18 and 65 years, this trend was not significant. VTEC was isolated from 140 (67.9%) vtx-positive stools. One sample yielded two different serotypes; thus, 141 isolates could be characterized. Sixty different O:H serotypes harboring 85 different virulence profiles were identified. Serotypes O157:H7/H؊ (n ‫؍‬ 34), O26:H11/H؊ (n ‫؍‬ 21), O63:H6 (n ‫؍‬ 8), O111:H8/H؊ (n ‫؍‬ 7), and O146:H21/H؊ (n ‫؍‬ 6) accounted for 53.9% of isolates. All O157 isolates carried vtx2, eae, and a complete O island 122 (COI-122); 15 also carried vtx1. Non-O157 isolates (n ‫؍‬ 107), however, accounted for the bulk (75.9%) of isolates. Fifty-nine (55.1%) isolates were positive for vtx1, 36 (33.6%) were positive for vtx2, and 12 (11.2%) carried both vtx1 and vtx2. Pulsed-field gel electrophoresis revealed wide genetic diversity; however, small clusters of O157, O26, and O63:H6 VTEC that could have been part of unidentified outbreaks were identified. Antimicrobial resistance was observed in 63 (44.7%) isolates, and 34 (24.1%) showed multidrug resistance. Our data show that VTEC infections were not limited to patients with HUS or bloody diarrhea. Clinical laboratories should, therefore, screen all stools for O157 and non-O157 VTEC using selective media and a method for detecting verocytotoxins or vtx genes. V erocytotoxin-producing Escherichia coli (VTEC), also called Shiga toxin-producing E. coli (STEC), is associated with diarrhea, often bloody, that may be complicated with hemorrhagic colitis and the life-threatening hemolytic-uremic syndrome (HUS), especially in children and the elderly (29). VTEC is characterized by its ability to produce one or more phage-encoded verocytotoxins, VT1 and VT2, that show distinct immunogenic and genetic properties (42). Multiple subtypes of VT1 (VT1a, VT1c, and VT1d) and VT2 (VT2a to VT2g), with significant diff...

Ocorrência de Escherichia coli O157:H7 e O26 sorbitol negativas em matadouro frigorífico de bovino e suscetibilidade a antimicrobianos

“…A ocorrência de E. coli O157:H7 neste estudo (12,0%) foi maior do que a relatada por Vaz et al (2004), em um estudo retrospectivo de E. coli em humanos no Brasil (6,67%), e por Buvens et al (2012), em um estudo sobre a a incidência e determinantes de virulência de STEC em casos de infecções na Bélgica (0,23%). Já Kappeli et al (2011) obtiveram STEC O157:H7 em 100% das amostras provenientes de casos clí-nicos na Suíça.…”

“…Paddock et al (2012), verificando a aplicabilidade da PCR multiplex para detectar E. coli não-O157 e O157 em bovinos, identificaram a E. coli O157 em 49,0% e O26 em 82,0% das amostras, valores maiores que os obtidos neste trabalho, de 12,0% e 8,0%. Já Buvens et al (2012), ao estudarem STEC em casos de infecções na Bélgica, relataram menor ocorrên-cia de E. coli O26 (0,14%) em relação a este estudo (8,0%).…”

“…Patógenos pertencentes ao sorogrupo das E. coli não-O157 são considerados emergentes e um problema para a saúde pública, uma vez que eles também têm sido associados a doenças severas em seres humanos, como a Síndrome Hemolítica Urêmica (SHU), Colite Hemorrágica (CH) e outras doenças gastrointestinais (Buvens et al, 2012;Sasaki et al, 2012).…”

“…Os sorotipos O26 e O113 são considerados patógenos emergentes, responsáveis por surtos de doença de origem alimentar em diversos países (Mathusa et al, 2010;Joris et al, 2011;Monaghan et al, 2011), sendo que o sorotipo predominantemente responsável por causar doenças severas nos humanos é o O26 (Buvens et al, 2012;Sasaki et al, 2012).…”

“…A ocorrência e a suscetibilidade de E. coli O157 e não-O157 a antimicrobianos têm sido estudadas (Schroeder et al, 2002;Vaz et al, 2004;Joris et al, 2011;Buvens et al, 2012;Sasaki et al, 2012), entretanto, há poucos relatos desses sorotipos em abatedouros bovinos, principalmente no Brasil.…”