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[In vitro susceptibility of Pasteurella and related bacteria to five orally administered antibiotics]
C Lion1, A Lozniewski, M C Conroy
1Laboratoire de Bactériologie, CHU, Hôpital Central, Nancy, France.
Abstract:
Tetracyclines and beta-lactam antibiotics are usually recommended for the treatment of pasteurellosis following bite wounds. However other oral antimicrobial agents could be proposed. In vitro susceptibility of 94 Pasteurella strains [P. multocida (79), P. stomatis (11), P. dagmatis (2), P. canis (1), P. "SP" (1)], 20 group EF-4 strains and 28 Neisseria weaveri strains (formerly group M-5), that are bacteria often isolated after animal-inflicted wounds, was studied towards five antibiotics: clarithromycin, azithromycin, pristinamycin, trimethoprim-sulfamethoxazole and ciprofloxacin. MICs were determined by the agar dilution method using HTM medium (Oxoïd), and for pristinamycin using both HTM and Mueller-Hinton agar supplemented with 5% horse blood (BMH). Most of Pasteurella isolates showed intermediate susceptibility to clarithromycin (63%) and to azithromycin (90.5%) with lower MICs for azithromycin. Fourty-two and thirty-two percent of Pasteurella strains were susceptible to pristinamycin respectively on HTM and on BMH. EF-4 and N. weaveri were more sensitive than Pasteurella to macrolides and to pristinamycin. Trimethoprim-sulfamethoxazole was active against all isolates, with higher MICs for EF-4 and N. weaveri. On all strains tested, the lowest MICs were observed for ciprofloxacin. Trimethoprim-sulfamethoxazole and ciprofloxacin could be proposed as a therapeutic alternative in case of pasteurellosis following animal bites.
Insights
This study evaluated alternative antibiotics for pasteurellosis, a common infection from animal bites. Trimethoprim-sulfamethoxazole and ciprofloxacin showed promising activity against Pasteurella, EF-4, and Neisseria weaveri strains.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Pasteurellosis, often resulting from animal bites, is typically treated with tetracyclines or beta-lactams.
- Alternative oral antimicrobial agents warrant investigation for effective treatment options.
Purpose of the Study:
- To assess the in vitro susceptibility of common bacteria isolated from animal bite wounds to various oral antibiotics.
- To identify potential alternative therapeutic agents for pasteurellosis.
Main Methods:
- Evaluated the in vitro susceptibility of 94 Pasteurella strains, 20 EF-4 group strains, and 28 Neisseria weaveri strains.
- Tested five antibiotics: clarithromycin, azithromycin, pristinamycin, trimethoprim-sulfamethoxazole, and ciprofloxacin using agar dilution methods.
- Determined Minimum Inhibitory Concentrations (MICs) on HTM medium and for pristinamycin on HTM and Mueller-Hinton agar supplemented with horse blood (BMH).
Main Results:
- Most Pasteurella isolates exhibited intermediate susceptibility to clarithromycin (63%) and azithromycin (90.5%), with lower MICs for azithromycin.
- Susceptibility to pristinamycin varied (42% on HTM, 32% on BMH).
- EF-4 and N. weaveri strains were generally more susceptible to macrolides and pristinamycin than Pasteurella. Trimethoprim-sulfamethoxazole was active against all isolates, while ciprofloxacin demonstrated the lowest MICs across all tested strains.
Conclusions:
- Trimethoprim-sulfamethoxazole and ciprofloxacin show potential as alternative therapeutic options for pasteurellosis following animal bites.
- These antibiotics offer viable alternatives when standard treatments are not suitable or effective.