Shiga Toxin Producing <em>Escherichia coli</em> Infections and Associated Haemolytic Uraemic Syndrome in New Zealand Children: Twenty Three Years of Epidemiology and Clinical Observations

Abstract

Background:The epidemiology of childhood haemolytic uraemic syndrome in New Zealand was on active surveillance from January 1, 1998 to December 31, 2020. The aim of this study is to describe the demographic, epidemiological and some clinical features of childhood Shiga toxin producing E. coli infections (STEC) and its association with diarrhoea associated haemolytic uremic syndrome (D+HUS) over past 23 years. Methods:The New Zealand Paediatric Surveillance Unit (NZPSU) sent out a monthly report card to all practising paediatricians with conditions under active surveillance. Those paediatricians who had cared for a child aged 0 to 15 years of age with D+HUS in the past month were requested to report their patient to the NZPSU. The reporting clinicians were then contacted by the principal investigator who sent out a questionnaire to the clinician requesting patient clinical and laboratory information. The group was divided into 2 cohorts; A: 1998-2008 and B: 2009-2020 to examine trends in STEC infections and childhood D+HUS.Results: Two hundred and twenty six children aged 3 months up to 15 years (median 2.8 years (IQR 1.7-4.9) were diagnosed with D+HUS. E. coli O157: H7 was identified in 130 (57.1%) and 8 were due to serotypes 026 H11 and 0113. Over the 23 years, the mean annual incidence in children under age 5 between cohort A and cohort B was not statistically significant (2.2 per 100,000 vs. 2.85 per 100,000. The mean annual incidence was 1.2 per 100,000 in all children under age 15 for the whole study period. Disease severity as measured by the requirement for acute dialysis had not changed and was required in 128/226 (56.2%) of children for a median of 9 days (range 1-38). The overall mortality was 3/226 (1.3%), which was due exclusively to severe cerebral injury. Conclusion:There has been an increase in STEC infections in childhood over the past 23 years, in part due improved methods of detection, however, the incidence children developing D+HUS has remained stable over the study period. E. coli serotypes other than O157:H7 have increased in prevalence over the past 6 years due to methodological changes in diagnostic laboratories, but with only a small number of infected children developing D+HUS. The mortality rate over the study period was low, consistent with other reported series.