Selection and characterization of a candidate therapeutic bacteriophage that lyses the Escherichia coli O104:H4 strain from the 2011 outbreak in Germany

Abstract

In 2011, a novel strain of O104:H4 Escherichia coli caused a serious outbreak of foodborne hemolytic uremic syndrome and bloody diarrhea in Germany. Antibiotics were of questionable use and 54 deaths occurred. Candidate therapeutic bacteriophages that efficiently lyse the E. coli O104:H4 outbreak strain could be selected rather easily from a phage bank or isolated from the environment. It is argued that phage therapy should be more considered as a potential armament against the growing threat of (resistant) bacterial infections.

Figure 1. Transmission electron micrographs of myovirus GEC-3S.

Phage particles were analyzed by transmission electron microscopy as described by Imberechts et al. . The head is somewhat elongated, appears hexagonal in outline and has a mean diameter of 102 nm (SEM = 3 nm). The head is separated from the tail by a neck. The tail is a rigid, contractile tube with a mean length of 109 nm (SEM = 1 nm). It appears cross-banded, suggesting helical symmetry. The tail ends in short and long fibers. The latter do not show up very well on this micrograph.

Figure 2. Pairwise DNA homology of GEC-3S and phi1, GEC-3S and RB49, GEC-3S and JSE, compared using a sliding window of 50 bp.