Background: Salmonella bacteria and A. galli worms cause serious illness, pathological defects and economic losses even in modern poultry production systems. This study was undertaken to elucidate the antibiotic sensitivity of Salmonella typhimurium when associated to A. galli.

Materials and Methods: Salmonella typhimurium LT2 was incubated in vitro in the presence and in the absence of A. galli, with three antibiotics: amoxicillin, cefepime and chloramphenicol.

Results: In the presence of A. galli worm the antibiotics showed a significant reduction in the ability to inhibit Salmonella typhimurium growth. Treatment of salmonellosis becomes less efficient when the bacteria are associated with A. galli worm.

Conclusion: A. galli may somehow protect the bacteria from the antibiotics through unknown mechanisms. However, further work is necessary to evaluate the mechanisms involved in the protection of A. galli.