This organism is one of the very few for which a single strain (found for example in infant #5, sample 1 shown here) was detected in multiple infants.
Antibiotic resistance genes can also spread through clonal expansion in successful pathogenic strains, for example, KPC in K. pneumoniae sequence type (ST) 258 (11 ), and the extended-spectrum β-lactamase CTX-M-15 in E. coli ST131 (12 ).
Extended monitoring of HAV strains, for example, as performed in the United States (13 ), could find hidden clusters and demonstrate links between imported and autochthonous cases.
This decreased efficiency is more apparent in some strains (for example, clb5 delete) than in other strains.
Microcystis spp. strains, for example, can differ significantly in their toxin content [19] and the potential predator (Daphnia spp).
Interestingly, the enzyme not only shows broad lytic activity against B. cereus strains but also lyses Gram-negative strains, for example, E. coli strains, in comparison with the phage lytic spectrum, which, most frequently, is limited to one B. cereus strain.
Between-group differences in reported values may be related to differences in rat strains (for example Sprague Dawley vs. Wistar), methodological differences, or differences in the severity of diabetes or the time that measurements were made after the onset of disease.
Considering the murine origin of E. coli NC101, it would also be interesting to test other E. coli strains, for example, clinical human CRC isolates, in this model.
However, it showed some variability between strains; for example, the T4SS genes were present in USDA 110T but were absent in CPAC 7 and USDA 6T.
Xenografting of human tumours into mice or rats has been performed since the late 1960s [ 1], but it was not until the advent of immunodeficient mouse strains (for example, severe combined immunodeficiency (SCID) mice) in the mid-1980s thet the practice became widespread in basic research and preclinical studies [ 2].
