Bartonella bacilliformis, endemic pathogen of the Andean region, is intrinsically resistant to quinolones

Luis J. del Valle, Lidia Flores, Martha Vargas, Ruth García-de-la-Guarda, Ruth L. Quispe, Zoila B. Ibañez, Débora Alvarado, Pablo Ramírez, Joaquim Ruiz

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Objectives: To analyze the sequence of the region involved in the development of quinolone resistance of the gyrA and parC genes in a series of Bartonella bacilliformis isolates recovered prior to the introduction of quinolones, as well as one clinical isolate recovered in the 1970s, establishing the susceptibility levels to nalidixic acid and ciprofloxacin. Methods: Five B. bacilliformis were studied: four isolated before 1957, prior to the introduction of quinolones in clinical practice. The remaining strain was isolated in 1977. A fragment of the gyrA and parC genes was amplified and sequenced. Susceptibility to nalidixic acid and ciprofloxacin was established by the E-test method. Results: All the strains were resistant to nalidixic acid (minimum inhibitory concentration (MIC) >256 mg/l). Three isolates presented decreased susceptibility to ciprofloxacin and two were highly resistant (MIC >32 mg/l). All the strains presented an Ala at position 91 of GyrA and position 85 of ParC. Conclusions: B. bacilliformis presents a constitutive resistance to quinolones, which may be related to the presence of Ala at position 91 of GyrA and 85 of ParC. These results advise against the current clinical guidelines recommending the use of ciprofloxacin to treat bartonellosis in some countries of the Andean area.

Original languageEnglish
Pages (from-to)e506-e510
JournalInternational Journal of Infectious Diseases
Issue number6
StatePublished - Jun 2010

Bibliographical note

Funding Information:
This work was partially funded by the AECID (Agencia Española de Cooperación Internacional para el Desarrollo) grant numbers A/3795/05, A/4892/06, A/9727/07 A/4817/06; ACCD (Agència Catalana de Cooperació al Desenvolupament, Generalitat de Catalunya) grant U2006; CCD-UPC (Centre de Cooperació per al Desenvolupament, Universitat Politècnica de Catalunya) to LJdV; and by the CONCYTEC (Consejo Nacional de Ciencia, Tecnología e Innovación Tecnológica, Perú) grant 189-2005-CONCYTEC-OAJ. JR's research is supported by grant CP05/0130 of the FIS (Fondo de Investigaciones Sanitarias).


  • Bartonella bacilliformis
  • Carrion's disease
  • Quinolones
  • Resistance
  • gyrA
  • parC


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