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Incremental increase in fitness cost with increased beta-lactam resistance in pneumococci evaluated by competition in an infant rat nasal colonization model
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UNSPECIFIED (2006) Incremental increase in fitness cost with increased beta-lactam resistance in pneumococci evaluated by competition in an infant rat nasal colonization model. In: 4th International Symposium on Pneumococci and Pneumococcal Diseases, MAY 09-13, 2004, Helsinki, FINLAND.
Full text not available from this repository.Abstract
Background. We evaluated the impact of resistant penicillin-binding protein ( PBP) allele acquisition on the ability of penicillin-resistant ( PEN-R) pneumococcal strains to compete with penicillin-susceptible ( PEN-S) ancestors for upper-respiratory-tract ( URT) colonization. Methods. PEN-S serotype 2, 6B, and 9V strains were transformed into derivatives expressing an increasing number of PEN-R PBP forms ( 2X, 2X-1A, and 2X-1A-2B for serotype 2 and 2X, 2X-2B, and 2X-2B-1A for 6B and 9V). Infant rats were inoculated intranasally with a mix of a PEN-R and PEN-S strains. For consecutive days, samples were collected for assessment of the ratio of PEN-S to PEN-R cells colonizing the URT. The selective index ( SI), defined as the change in the natural logarithm of the ratio of PEN-S to PEN-R strains from the inoculum to the nasal-wash samples, quantified differences in fitness. Results. SIs significantly > 0 ( indicating a cost of resistant allele acquisition) were observed 4-5 days after colonization in all but serotype 6B pbp2x transfomants. Additional replacements with low-affinity forms of pbp2b and pbp1a genes reduced further ability to compete in all strains. Conclusions. The cost of penicillin-resistance acquisition for the Streptococcus pneumoniae strain competing with its susceptible ancestor to colonize the URT increases with the number of resistant pbp alleles acquired.
| Item Type: | Conference Item (UNSPECIFIED) |
|---|---|
| Subjects: | Q Science > QR Microbiology > QR180 Immunology Q Science > QR Microbiology > QR355 Virology Q Science > QR Microbiology |
| Journal or Publication Title: | JOURNAL OF INFECTIOUS DISEASES |
| Publisher: | UNIV CHICAGO PRESS |
| ISSN: | 0022-1899 |
| Date: | 1 May 2006 |
| Volume: | 193 |
| Number: | 9 |
| Number of Pages: | 8 |
| Page Range: | pp. 1296-1303 |
| Publication Status: | Published |
| Title of Event: | 4th International Symposium on Pneumococci and Pneumococcal Diseases |
| Location of Event: | Helsinki, FINLAND |
| Date(s) of Event: | MAY 09-13, 2004 |
| URI: | http://wrap.warwick.ac.uk/id/eprint/33631 |
Data sourced from Thomson Reuters' Web of Knowledge
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