The clinical significance of AMINOGLYCOSIDEs is due to effect of gram-negative bacteria, staphylococcus aureus and some streptococcus. It is most application in the treatment of infections caused by facultative aerobic gram-negative bacilli. Combination of an AMINOGLYCOSIDE with beta-lactam or glycopeptide has synergistic effect on sensitive bacteria and can be effective in the treatment. Today, some bacteria have multiple RESISTANCEs to some antibiotics, including AMINOGLYCOSIDEs. Acquired RESISTANCE to AMINOGLYCOSIDEs in Gram-negative bacteria and gram-positive bacteria have been reported. Three RESISTANCE mechanisms involve a change in the position of the ribosomal binding of drugs, decreasing drug permeability and enzymatic drug inactivation. So, Identification of RESISTANCE mechanisms and find new functional groups is important in reducing RESISTANCE.

Background: The objective of this study was identification and determination of antibiotic RESISTANCE of isolated clinical Enterococcus by Duplex-PCR method in Tehran’s Hospitals.Methods: In during 2013-2014, this study was carried out on a group of patient (n=350) in Baqiyatallah, Milad, and Emam khomeini Hospitals. These bacteria were identified by biochemical tests and specific culture. Their RESISTANCE to different antibiotics was detected by the disk diffusion test according to CLSI (2013). Using primers (aac (6') -Ie-aph (2'') -Ia and aph (3') -IIIa), a Duplex-PCR method was designed for identification of resistant Enterococci spp.Results: According to the screening test, from 150 investigated Enterococcus, 77% belonged to the E. feacalis species and 23% belonged to the E. feacium species. The highest RESISTANCE was observed for Gentamicin and Erythromycin, the lowest RESISTANCE was observed for Teicoplanin and Linezolid. Sixty-three of isolates (42%) containedaac (6') -Ie-aph (2'') - Ia gene and twenty-one (14%) possessed aph (3') -IIIa gene. It should be noted that 13 isolates (8.6%) were positive for both genes simultaneously.Conclusion: The present study showed that the two genes conferred RESISTANCE to AMINOGLYCOSIDEs, particular, Gentamicin and Streptomycin in Enterococci spp. The RESISTANCE is increasing in Tehran’s hospitals, thus they must be determined rapidly by molecular methods such as Duplex-PCR. This is the way for preventing infections in Tehran’s hospitals.

Background: This study aimed to investigate the occurrence of AMINOGLYCOSIDE RESISTANCE and the prevalence of the RESISTANCEmodifying enzyme genes, ant(3” )-III, ant(6’ )-Ia, aac(6′ )-Ieaph( 2” )-Ia, and aph(2’ )-Id, in Enterococcus strains isolated in Kermanshah Province, west of Iran. Methods: In this cross-sectional study, 108 enterococcal isolates from urine, wound, blood, and cerebrospinal fluid samples were collected. The Enterococcus species were recognized by standard phenotypic/biochemical tests. The antimicrobial RESISTANCE forms were detected using a disc diffusion method. Polymerase chain reaction was designed to identify AMINOGLYCOSIDE RESISTANCE genes, including ant(3” )-III, ant(6’ )-Ia, aac(6′ )-Ie-aph(2” )-Ia, and aph(2’ )-Id. Results: Totally, 108 strains with a final diagnosis of Enterococcus were extracted from 84 (77. 8%) urine, 14 (13%) wound, 6 (5. 6%) blood, and 4 (3. 7%) cerebrospinal fluid samples. Among the 108 Enterococcus specimens, 94 (87%) cases were Enterococcus faecalis and 14 (13%) were Enterococcus faecium. The highest frequency of RESISTANCE was observed for erythromycin (88. 9%), while the lowest was found for streptomycin (44. 4%). The frequency of high-level gentamicin RESISTANCE was 42. 2%. Among the identified specimens, 42. 6% contained the aac(6′ )-Ie-aph(2” )-I gene, 20. 4% contained the ant(6’ )-Ia gene, and 15. 7% contained the ant(3” )-III gene. A significant correlation was found between phenotypic gentamicin RESISTANCE and the presence of the AMINOGLYCOSIDE RESISTANCE genes (P<0. 05). Conclusion: This study showed the high RESISTANCE of Enterococcus strains isolated from hospital samples. Compared with the previous studies, the strains isolated in our study showed a higher percentage of RESISTANCE to AMINOGLYCOSIDEs.