Related Experiment Videos
Antibiotic sensitivity patterns in field isolates of Mycoplasma gallisepticum as a guide to chemotherapy
Abstract:
Control of Mycoplasma gallisepticum (Mg) infection in commercial poultry flocks has sometimes been achieved by the intensive use of antibiotics. In some cases, a single drug, tylosin tartrate, has been used repeatedly in prophylactic and therapeutic applications. It appears that this selective pressure can lead to the emergence of strains with reduced sensitivity to tylosin. This was observed in Mg strains isolated in 1978 from turkey breeding flocks repeatedly treated with tylosin, but not in isolates from acute disease outbreaks. Moreover, in a study of four recent outbreaks of mycoplasma respiratory disease in poultry, some of the Mg strains isolated in each of the outbreaks showed reduced sensitivity to tylosin and, at the same time, to spiramycin. This suggests that the buildup of these strains in the general pool of Mg is playing an increasingly significant role in clinical outbreaks. Periodic in vitro antibiotic sensitivity testing of field isolates of mycoplasma is indicated as a means of monitoring the impact of mass medication programs and as a guide to therapeutic treatment.
Insights
Intensive antibiotic use in poultry can lead to Mycoplasma gallisepticum (Mg) strains resistant to tylosin and spiramycin. Regular sensitivity testing is crucial for monitoring and effective treatment of respiratory disease outbreaks.
Area of Science:
- Veterinary Microbiology
- Antimicrobial Resistance
- Poultry Health
Background:
- Mycoplasma gallisepticum (Mg) infections are a significant concern in commercial poultry.
- Antibiotic use, particularly tylosin tartrate, is common for Mg control.
- Repeated antibiotic application may exert selective pressure, favoring resistant strains.
Purpose of the Study:
- To investigate the emergence of antibiotic-resistant Mycoplasma gallisepticum strains.
- To assess the impact of repeated tylosin treatment on Mg sensitivity.
- To evaluate the current role of resistant Mg strains in clinical outbreaks.
Main Methods:
- Isolation and in vitro antibiotic sensitivity testing of Mycoplasma gallisepticum field strains.
- Comparison of sensitivity profiles from different time periods and disease outbreak contexts.
- Analysis of Mg strains from turkey breeding flocks and recent poultry respiratory disease outbreaks.
Main Results:
- Mg strains isolated from turkey flocks with repeated tylosin treatment showed reduced sensitivity to tylosin.
- Recent Mg isolates from poultry outbreaks exhibited reduced sensitivity to both tylosin and spiramycin.
- Evidence suggests a buildup of these multi-drug resistant strains in the general Mg population.
Conclusions:
- Selective pressure from intensive antibiotic use drives the emergence of resistant Mg strains.
- Reduced sensitivity to tylosin and spiramycin in field isolates is increasingly significant in clinical outbreaks.
- Periodic in vitro antibiotic sensitivity testing is essential for monitoring mass medication programs and guiding treatment strategies.