Detection and Distribution of various HLAR Gene in Enterococcus faecalis and Enterococcus faecium by Multiplex-PCR

In recent years, three new aminoglycoside resistance genes such as aph (3ʹ)-IIIa and ant (4ʹ)-Ia, that encode for the APH (3ʹ) and ANT (4ʹ) have also been identified. The aim of this study was to come up with a multiplex-PCR procedure for detection of aac(6ʹ)-Ie–aph(2ʹʹ)-Ia, aph(3ʹ)-IIIa, ant(4ʹ)-Ia genes in the Enterococcus spp. clinical isolates.

100 samples were isolated from various specimens, from various hospitals in Tehran, Iran. The grown colonies were identified by standard biochemical and disc diffusion tests. Multiplex-PCR for aac (6’)-Ie -aph(2’’)-Ia , aph(3ʹ)-IIIa, ant(4ʹ)-Ia genes amplification were performed in order to confirm bacterial colonies as Enterococcus spp.

Eighty four (84%) Enterococcus spp. isolates were collected from the 100 specimens. The highest and lowest isolates were related to urine (48%) and sputum (2%). Antibiotic susceptibility test results showed that the highest and lowest resistance was related to tetracycline and nitrofurantoin, respectively. Multiplex PCR results revealed that aac (6ʹ)-Ie-aph (2ʹʹ)-Ia, ant (4ʹ)-Ia and aph (3ʹ)-IIIa genes were present in 6% of the isolated bacteria from the urine, 2% from the wound and 1% from the pleural samples. the aac (6ʹ)-Ie-aph (2ʹʹ)-Ia and aph (3ʹ)-IIIa genes were present in 25% of the isolated strains from the urine, 3% from the wound and 2% from the plural specimens. Nine percent of the strains were isolated from the urine, 3% from the wound and 1% from the plural were positive for aac (6ʹ)-Ie-aph (2ʹʹ)-Ia and ant (4ʹ)-Ia genes.

we had observed enterococci isolates with phenotypic resistance to HLAR and demonstrated aac(6′)-Ie-aph(2′′)-Ia and aph(3′)-IIIa genes more frequently occurring than other genes. A collection of AMEs are accountable for HLAR status among Enterococcus species. The aac (6ʹ)-Ie-aph (2ʹʹ)-Ia gene was detected more frequently than the other genes.