Case Report
Uncommon Shiga toxin-producing Escherichia coli serotype O165:HNM as cause of hemolytic uremic syndrome in São Paulo, Brazil

https://doi.org/10.1016/j.diagmicrobio.2007.04.023Get rights and content

Abstract

Current knowledge of the circulating enterohemorrhagic Escherichia coli (EHEC) strains as agents of severe infections has a significant impact on the improvement of diagnostic procedures and control strategies. This report describes a case of hemolytic uremic syndrome related to an uncommon EHEC O165:HNM serotype. As far as we know, this serotype has not been previously associated with human infections, nor has it been isolated from the animal reservoir in São Paulo, Brazil.

Introduction

Shiga toxin-producing Escherichia coli (STEC) strains are important foodborne pathogens recognized as the leading cause of sporadic cases and outbreaks of hemorrhagic colitis (HC) in industrialized nations, and are the major cause of diarrhea-associated hemolytic uremic syndrome (HUS) worldwide (Tarr et al., 2005). O157:H7 is the most prominent serotype associated with serious outbreaks and sporadic cases of HC and HUS, but in the last decade, some non-O157 STEC strains have also been reported as being related to intestinal illnesses and complications in several regions. STEC strains that are associated with these serious conditions are often referred to as enterohemorrhagic E. coli (EHEC), which belong mainly to the O157 serogroup but also frequently to the O26, O103, O111, and O145serogroups (Caprioli et al., 2005). In Brazil, albeit the current notion that STEC infections are of little significance, there are several reports showing their important role in severe diseases (Guth et al., 2002, Irino et al., 2002, Vaz et al., 2006). Although a nationwide surveillance system for HUS has been recently established, there is still a paucity of data, and efforts have been made to promptly diagnose STEC/EHEC from diarrhea-associated HUS in Brazil. In this article, we describe the identification and characterization of an uncommon EHEC serotype responsible for a case of HUS in São Paulo.

Section snippets

Case report and microbiology

RMGA is a 19-month-old girl who was admitted, with 3days of diarrhea and vomiting, to the emergency room of a private tertiary hospital in São Paulo on February 26, 2005. Epidemiologic and clinical data were collected using a standardized questionnaire. The infant had no significant medical history. The condition began with liquid stools without mucus or blood, and no antibiotics or any other medication was used. No ingestion of raw meat or unpasteurized milk in the preceding days was reported,

Discussion

EHEC strains of serogroup O165 have not been previously associated to human infections, nor have they been isolated from the animal reservoir in Brazil (Vaz et al., 2006, Irino et al., 2005, Irino et al., 2007, Vettorato et al., 2003). However, serotype O165:H25 was identified as an agent of HUS in Japan in the mid-1990s (Uchida et al., 1995), but it is not usually related to HC and HUS cases in other countries (Ethelberg et al., 2004, Friedrich et al., 2002, Keskimäki et al., 1998). Curiously,

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