Antimicrobial susceptibility profiles (MIC and MMC) against Mycoplasma gallisepticum and M. synoviae isolated from chicken farms in Thailand

Authors

Kriengwich Limpavithayakul, Avian Health Research Unit, Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn UniversityFollow
Alongkorn Amonsin, Center of excellence for emerging and re-emerging diseases in animals, Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn UniversityFollow
Nataya Charoenvisal, Avian Health Research Unit, Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn UniversityFollow
Arithat Limsatanun, Faculty of Veterinary Science, Prince of Songkla UniversityFollow
Katanyu Yangsuk, Eco Animal Health, United KingdomFollow
Sumrit Toopiya, Eco Animal Health, United KingdomFollow
Füsun Güngör, Eco Animal Health, London
Esther Schonewille, Eco Animal Health, London
Javier Uriarte, Eco Animal Health, London
Somsak Pakpinyo, Avian Health Research Unit, Department of Veterinary Medicine, Faculty of Veterinary Science, Chulalongkorn UniversityFollow

Abstract

Mycoplasma gallisepticum (MG) and M. synoviae (MS) are important pathogens causing significant economic losses in poultry production. Disease prevention and control strategies include vaccination, antimicrobial therapy, and strict biosecurity measures. The present study provides, for the first time, both minimum inhibitory concentration (MIC) and minimum mycoplasmacidal concentration (MMC) values as antimicrobial susceptibility profiles of Thai MG and MS field isolates. This study aimed to evaluate the susceptibility of five MG and ten MS isolates to various antimycoplasma drugs: doxycycline, lincomycin-spectinomycin, tiamulin, tilmicosin, tylosin, and tylvalosin, using a microdilution broth assay. For MG isolates, tilmicosin had the highest mean MIC (12.5 µg/mL), while tylvalosin presented the lowest MIC (0.0488 µg/mL). For MS isolates, lincomycin-spectinomycin showed the highest MIC (0.2148 µg/mL), and tylvalosin performed the lowest (0.0488 µg/mL). This study also demonstrates the MMC values, showing tilmicosin had the highest MMC (12.5 µg/mL) for MG field isolates, while doxycycline had the highest MMC (0.3320 µg/mL) for MS field isolates. Tylvalosin consistently demonstrated the lowest MIC and MMC values for both MG and MS field isolates, suggesting its outstanding efficacy. Importantly, MMC values were introduced as a practical and insightful complement to MIC values by revealing viability of MG and MS field isolates at MIC levels of doxycycline (12 of 15 isolates), lincomycin-spectinomycin (7 of 15 isolates), tiamulin (1 of 15 isolates), tilmicosin (3 of 15 isolates), tylosin (4 of 15 isolates), and tylvalosin (2 of 15 isolates). These findings provide valuable insights for integrating MIC and MMC analysis into routine antimicrobial selection, contributing to more effective disease control, offering both growth inhibition and bactericidal effectiveness, and rational antimicrobial use in poultry farming, which could mitigate antimicrobial resistance, especially in poultry farms with intensive usage of antimicrobials.

DOI

10.56808/2985-1130.3849

First Page

1

Last Page

9

Recommended Citation

Limpavithayakul, Kriengwich; Amonsin, Alongkorn; Charoenvisal, Nataya; Limsatanun, Arithat; Yangsuk, Katanyu; Toopiya, Sumrit; Güngör, Füsun; Schonewille, Esther; Uriarte, Javier; and Pakpinyo, Somsak (2025) "Antimicrobial susceptibility profiles (MIC and MMC) against Mycoplasma gallisepticum and M. synoviae isolated from chicken farms in Thailand," The Thai Journal of Veterinary Medicine: Vol. 55: Iss. 3, Article 3.
DOI: https://doi.org/10.56808/2985-1130.3849
Available at: https://digital.car.chula.ac.th/tjvm/vol55/iss3/3