Use of randomly cloned DNA fragments for identification of Bacteroides thetaiotaomicron

Abstract

Randomly cloned fragments of DNA from B. thetaiotaomicron were used as hybridization probes for differentiation of B. thetaiotaomicron from closely related Bacteroides spp. HindIII digestion fragments of DNA from B. thetaiotaomicron (type strain) were inserted into plasmid pBR322 and labeled with [.alpha.-32P]dCTP by nick translation. These labeled plasmids were screened for hybridization to HindIII digests of chromosomal DNA from type strains of the following human colonic Bacteroides spp.: B. thetaiotaomicron, B. ovatus, reference strain 3452-A (formerly part of B. distasonis), B. uniformis, B. fragilis, B. vulgatus, B. distasonis, B. eggerthii and reference strain B5-21 (formerly B. fragilis ssp. a). Two of the 5 cloned fragments hybridized only to DNA from B. thetaiotaomicron. Each of these 2 fragments hybridized to the same DNA restriction fragment in 5 strains of B. thetaiotaomicron other than the strain from which the DNA was cloned. One of the cloned fragments (pBT2) was further tested for specificity by determining its ability to hybridize to DNA from 65 additional strains of colonic Bacteroides.