Disease relevance of BF0141

• Common regulatory mechanism of expression and conjugative ability of a tetracycline resistance plasmid in Bacteroides fragilis [1].
• Cryptic tetracycline resistance determinant (class F) from Bacteroides fragilis mediates resistance in Escherichia coli by actively reducing tetracycline accumulation [2].
• Other tetracycline resistance determinants (classes A to E) isolated from gram-negative enteric bacteria expressed resistance and generated active efflux of tetracycline under anaerobic as well as aerobic conditions [2].
• In addition, this aerobic tetracycline resistance determinant is not homologous to the three major plasmid mediated tetracycline resistance regions found in facultative gram-negative bacteria, represented by R100, RK2, and pBR322 [3].
• Detection and prevalence of the tetracycline resistance determinant Tet Q in the microbiota associated with adult periodontitis [4].

High impact information on BF0141

• Recently, Tet Q, a tetracycline resistance determinant that confers resistance by a ribosome protection mechanism, was described and added to the two previously described classes, Tet M and Tet O [5].
• These results indicate that Tn4400 mediates two functionally different mechanisms for tetracycline resistance: an active efflux of tetracycline and a degradation of tetracycline [6].
• Three isolates resistant to high levels of clindamycin transferred tetracycline resistance to a sensitive Bacteroides fragilis recipient, and one of these (strain 1126) also transferred high-level clindamycin resistance [7].
• Resistance to tetracycline, erythromycin, and clindamycin in the Bacteroides fragilis group: inducible versus constitutive tetracycline resistance [8].
• The initial phase is independent of adenosine 5'-triphosphate synthesis, which is coupled to fumarate reduction; this phase is not altered by expression of tetracycline resistance genes in a resistant strain [9].

Chemical compound and disease context of BF0141

• Two tetracycline resistance determinants, tetM from Streptococcus agalactiae and tetC from E. coli, also were examined. tetC did not result in detectable tetracycline resistance but the gram-positive tetM gene conferred high-level resistance to tetracycline and minocycline in Bacteroides hosts [10].

Biological context of BF0141

• The second phase appears to occur by active transport, since it is largely reduced by rotenone, an inhibitor of electron transport to fumarate; moreover, this phase is under negative control of the tetracycline resistance gene [9].
• Control of the Tcr phenotype is unusual in that expression is constitutive and is enhanced by a region encompassing the adjacent direct repeat [11].
• By using Tn5 mutagenesis and subcloning, we localized the Clr and Tcr regions on the EcoRI B fragment between the 1.2-kilobase direct repeats of pCP1 [11].
• Similarly, a conjugative plasmid (pRRI4) originally found in P. ruminicola 223 was transferred from P. ruminicola B(1)4 to B. uniformis or B. thetaiotaomicron. pRRI4 could be transferred from the colonic Bacteroides species only if the donor strain contained the Tcr Emr 12256 element in its chromosome [12].
• We detected conjugation systems in isolates of Bacteroides denticola and Bacteroides intermedius that transferred tetracycline resistance (Tetr) and penicillin resistance to Bacteroides buccae and to Bacteroides fragilis, an intestinal Bacteroides species [13].

Associations of BF0141 with chemical compounds

• Drug-resistant progeny from V503 x V528 matings (with or without pVA503) conjugally transferred clindamycin resistance an tetracycline resistance to a suitable recipient strain [14].
• Curing experiments demonstrated that the plasmid, referred to as pBY22 when present in transformants, was responsible for penicillin G and tetracycline resistance [15].
• Chloramphenicol, erythromycin and clindamycin resistance markers were cured en bloc after exposure to the agents for 24 hr but elimination to tetracycline resistance markers required longer incubation (17-21 days) with the reagents [16].

Analytical, diagnostic and therapeutic context of BF0141

• Each different colony morphotype was enumerated, and a representative colony was subcultured for identification and examined for the tetracycline resistance gene tet(Q) by polymerase chain reaction (PCR) amplification and DNA hybridization, using a fragment of tetA(Q)2 from Bacteroides fragilis 1126 [4].

References