Cloacal Lactobacillus isolates from broilers show high prevalence of resistance towards macrolide and lincosamide antibiotics

Eighty-seven Lactobacillus strains isolated from cloacal swabs of broiler chickens derived from 20 different farms in Belgium were identified to species level and tested for susceptibility to macrolide and lincosamide antibiotics. Five different Lactobacillus species were identified as being predominantly present in the cloacae of broilers: Lactobacillus crispatus, Lactobacillus salivarius subsp. salivarius, Lactobacillus amylovorus, Lactobacillus gallinarum and Lactobacillus reuteri. Acquired resistance prevalence to macrolides and lincosamides was very high in the investigated lactobacilli: 89% of the strains were resistant to either or both lincosamide and macrolide class antibiotics. The vast majority of these resistant strains ( 96%) displayed constitutive resistance. More than one-half of the macrolide and/or lincosamide resistant strains carried an erm( B), erm( C), mef( A), lnu( A) gene or a combination of these genes.