Two possible evolutionary hypotheses to explain the deep-branching of these strains are proposed: (A), the Australian indigenous strains have evolved from a separate zoonotic transmission event, or alternate intermediate strain, to that of the other human C. pneumoniae strains.
The two Finnish strains have evolved from a common ancestor during the last 200 years.
Based on this study, we estimate that the Finnish EBLV-2 strains and one Swiss strain from among the other EBLV-2 strains have evolved from a common ancestor during the last 1000 years.
On the other hand, MRSA strains have evolved from a small number of clonal strains, so the likelihood of isolating MRSA with phenotypic and genetic similarities during our isolation procedure was high (Enright et al. 2002; Fang and Hedin 2003; Oliveira et al. 2002).
43, 44 However, the notion that S. aureus strains have evolved to thrive within a single species 45 was recently challenged by reports of LA-MRSA strains infecting livestock-associated workers, 46 human-to-poultry-transfer of sequence type (ST -5 ST -5nstrainsnd transmission of such strains as USA100, USA300, and USA500 between humans and their companion animals.
Overall, these data show that the pathogenic Bacillus strains have evolved ways to adapt gene expression in a more profound and extensive way in different atmospheric conditions.
Although altered El Tor strains have evolved only within the past several decades, which also argues against a long-standing environmental source (8 ), VNTR analysis, with its rapid molecular clock, can be used to test theories about the origin of the strain in Haiti and provide a unique opportunity to follow diversification of this clone over time and with human passage during an epidemic.
Though antibiotics once tamed the bugs easily, strains have evolved resistance, the toughest to treat being methicillin-resistant S. aureus (MRSA).
A new study published online yesterday in Nature Genetics offers a provocative explanation for its success in sub-Saharan Africa: Strains have evolved that appear to spread from person to person, unlike other NTSs.
That's particularly critical because many TB strains have evolved defenses against standard treatments.
