Household transmission and carriage of Shiga toxin-producing Escherichia coli (STEC) O145, Stx1c: a family report

Abstract

Background: Infections induced by Shiga toxin-producing Escherichia coli (STEC), especially non-O157 serogroups like O145, pose considerable public health risks. Household transmission is crucial in the dissemination of STEC, particularly in settings characterized by close interaction, such as extended families. This study examines a case of a 5-month-old infant with hemolytic uremic syndrome (HUS) attributed to stx1c-positive STEC and analyzes transmission patterns within the household.

Methods: Perianal swab samples were obtained from a 5-month-old infant diagnosed with STEC-associated HUS and six additional household members. Samples of breast milk were examined as well. Samples were inoculated into sorbitol MacConkey agar (SMAC) and cefixime tellurite sorbitol MacConkey agar (CT-SMAC). Polymerase chain reaction (PCR) was utilized to identify stx1, stx2, and O serogroups. Fecal shedding was investigated over a four-month period with repeated sampling.

Results: Six household members, including the infant, tested positive for stx1, although the mother and breast milk samples were negative. The detected strains were classified within the O145 serogroup and exhibited the stx1c variation. Fecal shedding continued for up to four months in the majority of family members, with the infant exhibiting the briefest length of shedding. The family indicated regular intake of raw meatballs ("çiğköfte"), a traditional Turkish food, made with raw meat, identified as a possible source of illness. None of the family members displayed any symptoms except for the infant, who had severe HUS.

Conclusion: This study underscores the critical impact of household transmission on the dissemination of STEC and the hazards associated with traditional raw meat meals such as çiğköfte. Non-O157 STEC serogroups, including O145, are increasingly recognized as significant agents of human infections. The results underscore the significance of monitoring, hygiene education, and preventive strategies to mitigate the dissemination of STEC in families and the wider community. Mitigating extended fecal shedding and detecting foodborne transmission sources are essential for effective public health intervention.

Keywords: STEC O145; hemolytic uremic syndrome; shiga toxin-producing Escherichia coli; stx1c.