Comparison of transformation frequencies among selected Streptococcus pneumoniae serotypes
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Date
2010
Journal Title
Journal ISSN
Volume Title
Publisher
International journal of antimicrobial agents
Abstract
Although there are over 90 serotypes of Streptococcus pneumoniae, antimicrobial resistance is predominantly
found in a limited number of serotypes/serogroups, namely 6, 9, 14, 19 and 23. There is no
compelling mechanism to account for this restriction. We aimed to determine whether serotypes commonly
associated with drug resistance have higher transformation frequencies than those that are
susceptible to antimicrobial agents. An in vitro investigation of the genetic transformation frequency
of drug-resistant serotypes compared with that of susceptible serotypes under the influence of synthetic
competence-stimulating peptides was performed. The transforming DNA was genomic DNA carrying a
Tn916-like transposon containing the mefE gene that confers resistance to erythromycin. It was observed
that serotypes 6, 9, 14, 19 and 23, which are highly associated with drug resistance, do not exhibit a
higher degree of transformation efficiency than other serotypes. These findings suggest that the association
of serotype with drug resistance is likely due to prolonged exposure to transforming DNA resulting
from longer nasopharyngeal carriage and to a greater selective pressure from antimicrobials, particularly
in children. This is the first study to compare the transformation frequencies of pneumococcal clinical
isolates using genomic DNA that carries the composite Tn916-like element.
Description
Keywords
Streptococcus, pneumoniae, Drug-resistant serotypes serogroups
Citation
Joloba, M. L., Kidenya, B. R., Kateete, D. P., Katabazi, F. A., Muwanguzi, J. K., Asiimwe, B. B., ... & Jacobs, M. R. (2010). Comparison of transformation frequencies among selected Streptococcus pneumoniae serotypes. International journal of antimicrobial agents, 36(2), 124-128. doi:10.1016/j.ijantimicag.2010.03.024