Epidemiology of Escherichia coli serogroups O26, O103, O111 and O145 in very young ('bobby') calves in the North Island, New Zealand

Abstract

The prevalence and spatial distribution of Escherichia coli serogroups O26, O103, O111 and O145 in calves 70% similarity) using pulsed field gel electrophoresis. Mapping of the farms showed the presence of farms positive for O26, O103 and O145 in three important dairy producing regions of the North Island. Calves positive for O103 were more likely to be positive for O26 and vice versa (P = 0·04). Similarly, calves positive for O145 were more likely to be positive for O103 and vice versa (P = 0·03). This study demonstrates that non-O157 E. coli serogroups of public health and economic importance containing clinically relevant virulence factors are present in calves in the North Island of New Zealand.

Keywords: Calves; New Zealand; non-O157 STEC.

Fig. 1.

Map showing the distribution of the farm of origin of E. coli O26, O103 and O145-positive calves in North Island, New Zealand. The data are aggregated to 5 × 5 km grid cells. Only cells containing farms that submitted calves to the abattoir that were subsequently sampled are displayed. If a single animal was positive the grid cell was coloured grey. If no animals sampled were positive the cell was coloured black.

Fig. 2.

The K function analysis of (a) E. coli O26-positive (cases) and E. coli O26-negative (control) farms (b) O103, and (c) O145. The black line represents the difference between the two K functions and dashed lines represent the upper and lower simulation envelopes.

Fig. 3.

Clustering (UPGMA dendrogram) of the PFGE profiles of E. coli O26 isolates recovered from bobby calves from the North Island of New Zealand with >70% similarity cut off using XbaI. The last lane is the Salmonella serotype Braenderup reference standard (H9812).