Species of the obligate anaerobe, Bacteroides occupy a prominent position in the microbial ecology of the human oral cavity and intestinal tract. Although normally indigenous, Bacteroides of oral origin are often associated with periodontopathic dental plaque. One intestinal species, B. fragilis, is the most commonly isolated anaerobic organism from soft-tissue infections. The emergence of resistance to the drug of choice, clindamycin (Ccr), and to other antibiotics threatens to compromise the treatment of Bacteroides infections. Although resistance phenotypes have been traced to plasmids, many strains possess transferable resistance elements that are not associated with plasmid DNA. In this application we shall test the hypothesis that the Ccr determinant of a B. fragilis plasmid, pBF4, is a transposon. These studies will involve base sequence analysis of the ends of this putative transposon and genetic tests of its ability to undergo serial transposition. Major effort will be directed towards defining the genetic basis of the non-plasmid associated Ccr in Bacteroides. Using physical and genetic approaches we shall test the hypothesis that one such element occupies a chromosomal integration site. We shall also explore the possibility that resistance transfer elements occur in oral Bacteroides and we shall assess their ability to exchange resistance determinants with intestinal species. This work will use a wide array of modern genetic methodology including mutant isolation, transmission genetics, molecular cloning, in situ filter blot hybridization and DNA base sequence analysis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE009035-07
Application #
3222848
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1988-09-01
Project End
1993-08-31
Budget Start
1989-09-01
Budget End
1990-08-31
Support Year
7
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Virginia Commonwealth University
Department
Type
Overall Medical
DUNS #
City
Richmond
State
VA
Country
United States
Zip Code
23298
Macrina, F L (1992) Bacterial diseases of the oral tissues. Adv Exp Med Biol 327:25-34
Fletcher, H M; Macrina, F L (1991) Molecular survey of clindamycin and tetracycline resistance determinants in Bacteroides species. Antimicrob Agents Chemother 35:2415-8
Halula, M C; Manning, S; Macrina, F L (1991) Nucleotide sequence of ermFU, a macrolide-lincosamide-streptogramin (MLS) resistance gene encoding an RNA methylase from the conjugal element of Bacteroides fragilis V503. Nucleic Acids Res 19:3453
Macrina, F L; Jones, K R; Alpert, C A et al. (1991) Repeated DNA sequence involved in mutations affecting transport of sucrose into Streptococcus mutans V403 via the phosphoenolpyruvate phosphotransferase system. Infect Immun 59:1535-43
Macrina, F L; Dertzbaugh, M T; Halula, M C et al. (1990) Genetic approaches to the study of oral microflora: a review. Crit Rev Oral Biol Med 1:207-27
Halula, M; Macrina, F L (1990) Tn5030: a conjugative transposon conferring clindamycin resistance in Bacteroides species. Rev Infect Dis 12 Suppl 2:S235-42