Key points The frequencies of genes associated with adeB, adeG, adeJ and abeM efflux pump were 100%, 92.8%, 86% and 98.5%, respectively. Real-Time PCR results showed a correlation between the antibiotic effects of Tigecycline on adeB gene expression. The antibiotic resistance of the isolates was relatively high. Also, efflux pump genes, which are the antibiotic resistance factors of A. baumannii, are frequently high in the isolates but it seems that isolates use other effluxe pumps than RND family to exit tigecycline.