Enrofloxacin and macrolides alone or in combination with rifampicin as antimicrobial treatment in a bovine model of acute Chlamydia psittaci infection

PLoS One. 2015 Mar 13;10(3):e0119736. doi: 10.1371/journal.pone.0119736. eCollection 2015.

Abstract

Chlamydia psittaci is a zoonotic bacterium with a wide host range that can cause respiratory disease in humans and cattle. In the present study, effects of treatment with macrolides and quinolones applied alone or in combination with rifampicin were tested in a previously established bovine model of respiratory C. psittaci infection. Fifty animals were inoculated intrabronchially at the age of 6-8 weeks. Seven served as untreated controls, the others were assigned to seven treatment groups: (i) rifampicin, (ii) enrofloxacin, (iii) enrofloxacin + rifampicin, (iv) azithromycin, (v) azithromycin + rifampicin, (vi) erythromycin, and (vii) erythromycin + rifampicin. Treatment started 30 hours after inoculation and continued until 14 days after inoculation (dpi), when all animals were necropsied. The infection was successful in all animals and sufficient antibiotic levels were detected in blood plasma and tissue of the treated animals. Reisolation of the pathogen was achieved more often from untreated animals than from other groups. Nevertheless, pathogen detection by PCR was possible to the same extent in all animals and there were no significant differences between treated and untreated animals in terms of local (i.e., cell count and differentiation of BALF-cells) and systemic inflammation (i.e. white blood cells and concentration of acute phase protein LBP), clinical signs, and pathological findings at necropsy. Regardless of the reduced reisolation rate in treated animals, the treatment of experimentally induced respiratory C. psittaci infection with enrofloxacin, azithromycin or erythromycin alone or in combination with rifampicin was without obvious benefit for the host, since no significant differences in clinical and pathological findings or inflammatory parameters were detected and all animals recovered clinically within two weeks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Azithromycin / pharmacology
  • Cattle
  • Chlamydophila psittaci / drug effects*
  • Disease Models, Animal
  • Enrofloxacin
  • Erythromycin / pharmacology
  • Fluoroquinolones / pharmacology*
  • Inflammation / drug therapy
  • Inflammation / microbiology
  • Macrolides / pharmacology*
  • Male
  • Psittacosis / drug therapy*
  • Psittacosis / veterinary*
  • Rifampin / pharmacology

Substances

  • Anti-Bacterial Agents
  • Fluoroquinolones
  • Macrolides
  • Enrofloxacin
  • Erythromycin
  • Azithromycin
  • Rifampin

Grants and funding

This study was financially supported by the Federal Ministry of Education and Research (BMBF) of Germany under Grant no. 01 KI 0720 “Zoonotic chlamydiae—Models of chronic and persistent infections in humans and animals”. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. LIPIDOMIX GmbH provided support in the form of salaries for author Michael Rothe, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of this author is articulated in the ‘author contributions’ section.