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Title:Tetracycline resistance and its dissemination in the Bacteroides group
Author(s):Nikolich, Mikeljon Peter
Doctoral Committee Chair(s):Salyers, Abigail A.
Department / Program:Microbiology
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Biology, Molecular
Biology, Microbiology
Abstract:Tetracycline resistance (Tc$\sp{\rm r})$ in the human colonic Bacteroides and in the related genus Prevotella appears to be conferred by a single resistance determinant. This determinant represents a new class of ribosome protection Tc$\sp{\rm r}$ genes which was designated TetQ, because it has a deduced amino acid sequence that is 40% identical to TetM or TetO (which are $>$75% identical). A deep evolutionary relationship was found to exist between the ribosome protection Tc$\sp{\rm r}$ genes and the elongation factors, particularly the EF-G/EF-2 family. The early divergence between these lineages indicates that the ribosome protection Tc$\sp{\rm r}$ genes are of a more ancient origin than was previously believed. Like tetM and tetO, which have been disseminated in diverse bacterial groups, tetQ appears to be spreading by horizontal transmission within the Bacteroides group. Identical tetQ sequences were found in a number of isolates with differing taxonomy and geographic origin, indicating that extensive natural gene transfer has occurred. Among the exchange events indicated by the evidence was the very recent transfer of an allele of tetQ usually found in Prevotella to a Bacteroides fragilis strain. A new tetQ-containing chromosomal element from Bacteroides, Tc$\sp{\rm r}$Em$\sp{\rm r}$ 7853, was capable of this type of broad host range transfer. Tc$\sp{\rm r}$Em$\sp{\rm r}$ 7853 appears to have structural relatives in isolates of Prevotella ruminicola, indicating that a larger family of elements may be maintained in Bacteroides and Prevotella species, and may be capable of transferring antibiotic resistance between the genera in nature.
Issue Date:1994
Rights Information:Copyright 1994 Nikolich, Mikeljon Peter
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9503288
OCLC Identifier:(UMI)AAI9503288

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