Enterococci are gram-positive bacteria and the source of recurrent nosocomial infections with high levels of antibiotic resistance (1), of which we can name resistance to cephalosporins, aminoglycosides, monobactams, penicillinase resistance penicillins, and most importantly, vancomycin (2). Between 85% to 90% of the enterococci infections are caused by Enterococcus faecium (2), and macrolide-lincosamide-streptogramin is an antibiotic, which can be useful for treating enterococcal infections (1). M phenotype refers to a resistance mechanism to macrolides (such as erythromycin) and includes activedrug efflux pumps that are encoded by mef genes (3,4). For the first time, bacterial antibiotic efflux was reported in 1970 (3). The presence of mef genes have been reported in previous studies (6). In the current study, we reported mefE gene in E. faecium ATCC (American Type Culture Collection) 51559. Acinetobacter baumannii is a gramnegative bacterium that has turned into a great concern in the health care centers especially in intensive care units (4). The name Acinetobacter is originated from akinetos, a Greek word meaning non-motile (4). A. baumannii is a member of "ESKAPE" (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, A. baumannii, Pseudomonas aeruginosa and Enterobacter spp.) group which consist of multi-drug resistant organisms (4). It is one of the important causes of nosocomial infections (5). Among these multi-drug resistance traits, chromosomal AmpC, a non-inducible cephalosporinase, was already reported in A. baumannii genome (4). In this study, we reported AmpC resistance gene in A. baumannii ATCC 19606. The mentioned ATCC bacteria, which were isolated from clinical 10 µL of the Master Mix Red (Amplicon, Denmark), 0.5 µL of each primer, and 3 µL of the respective DNA templates, and then brought to a total volume of 25 µL by adding deionized distilled water. Reaction cycles for MefE gene included an initial 7-minute denaturation at 95˚C, followed by 44 cycles of: denaturation at 95˚C