Abstract:
:Long-term antibiotic treatment offers a rare opportunity to study the evolution of bacteria within the same individual. The appearance of new variants has been suggested to take place via the selection of enhanced resistance in compartments of the body in which the antibiotic concentration is low. Laboratory models of protected compartments have elegantly demonstrated their potential in selecting novel variants. However, comparable data from patients have been rare. In this study, extended antibiotic therapy in a single patient suffering from multiple infected liver cysts has provided the opportunity to observe and analyse the molecular evolution of antibiotic resistance. Each isolate has the same basic ompC gene sequence that is distinct from other Escherichia coli isolates, which suggests that they derive from the same founder population. However, the isolates differ in their auxotrophic markers, in the pI values of their dominant beta-lactamase activities and in the mutations in the promoter region of the ampC gene leading to increased expression of the AmpC enzyme. The data provide strong evidence for a single focal infection expanding via parallel pathways of evolution to give a range of antibiotic-resistant isolates. These data suggest that the infected cysts provide numerous protected environments that are the foci for the separate development of distinct variants.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Low AS,MacKenzie FM,Gould IM,Booth IRdoi
10.1046/j.1365-2958.2001.02647.xsubject
Has Abstractpub_date
2001-11-01 00:00:00pages
619-30issue
3eissn
0950-382Xissn
1365-2958pii
2647journal_volume
42pub_type
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