Molecular characterization of a carbon dioxide-dependent Escherichia coli small-colony variant isolated from blood cultures

Takehisa Matsumoto, Masayuki Hashimoto, Ching Hao Teng, Po Chuen Hsu, Yusuke Ota, Masaru Takamizawa, Ryosuke Kato, Tatsuya Negishi

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

A carbon dioxide-dependent small-colony variant of Escherichia coli SH4888 was isolated from blood cultures of a patient with cholangitis. To date, little is known regarding the molecular mechanisms leading to formation of carbon dioxide-dependent phenotypes in clinical isolates, but abnormalities in the carbonic anhydrase are thought to cause carbon dioxide autotrophy. In this study DNA sequence analysis of the carbonic anhydrase-encoding can locus in the carbon dioxide-dependent E. coli SH4888 revealed that the isolate had a 325-bp deletion spanning from the 3′-terminal region of can to the 3′-terminal region of hpt, which encodes a hypoxanthine phosphoribosyltransferase. To confirm that the carbon dioxide-dependent SCV phenotype of E. coli SH4888 was due to the can mutation, we performed a complementation test with a plasmid carrying an intact can that restored the normal phenotype. However, E. coli SH4888 had increased virulence compared to the can-complemented E. coli SH4888 in a murine infection model. In conclusion, these data confirm that impaired carbonic anhydrase function can cause a carbon dioxide-dependent SCV phenotype in E. coli SH4888 and provides a fitness advantage in terms of infection.

Original languageEnglish
Article number151431
JournalInternational Journal of Medical Microbiology
Volume310
Issue number5
DOIs
Publication statusPublished - 2020 Jul

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Microbiology (medical)
  • Infectious Diseases

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