Increased incidence of Escherichia coli bacteremia post-Christchurch earthquake 2011: possible associations.

Introduction: Earthquakes are natural events that contribute to the transmission of infectious diseases. The aim of this research was to determine whether the observed increase in Escherichia coli (E. coli) bloodstream infections (BSI) during the period March-June 2011 was associated with the February 2011 Christchurch earthquake.

Methods: Descriptive statistics and spatial distributional analysis techniques were used to quantify patients with E. coli BSI in 2009-2011.

Results: E. coli BSI acquired from non-catheter related urinary tract infection (UTI) was the predominant infection type, with the greatest increase during March-June 2011. Bacteremia incidence was higher in females than in males for 2009-2011. In 2011, the median age of patients was 75 years, and an increase in males acquiring such infections was noted. Spatial distributional analysis failed to show direct association between bacteremia cases and liquefaction-related land damage or drinking water contamination. A higher incidence of E. coli BSI post-earthquake in the eastern suburbs, which tend towards a higher level of socioeconomic deprivation, was observed.

Conclusion: A number of possible factors contributing to the observed increase in E. coli BSI acquired from UTI in 2011 were considered. Individuals with higher deprivation indices, males and the elderly may be particularly vulnerable to the effects of a major disaster with subsequent breakdown of infrastructure. These findings have important implications in natural disaster situations, and justify development of strategies to identify UTI and pyelonephritis risk factors and to manage E. coli bacteremia incidence rates.