Distribution of genes encoding resistance to aminoglycoside modifying enzymes in methicillin‐resistant Staphylococcus aureus (MRSA) strains

Abstract

Today Methicillin-Resistant Staphylococcus aureus (MRSA) have acquired multiple resistance to a wide range of antibiotics including aminoglycosides. So, this study was aimed to investigate the rate of aminoglycoside resistance and the frequency of aminoglycoside resistance mediated genes of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia among MRSA strains. A total of 467 staphylococci isolates were collected from various clinical samples. S. aureus strains were identified by standard culture and identification criteria and investigating of presence of 16S rRNA and nuc genes. Cefoxitin disk diffusion, and oxacillin-salt agar screening methods were used to detect the MRSA strains with subsequent molecular identification for the presence of mecA gene. Antibiotic susceptibility of MRSA strains against aminoglycoside antibiotics was evaluated by using agar disk diffusion method. Multiplex PCR for the presence of aac(Ia)-2, aph(3)-IIIa and ant(4')-Ia encoding genes for aminoglycosides were performed for MRSA strains. From total staphylococci tested isolates, 262 (56.1%) were identified as S. aureus, of which 161 (61.45%) were detected as MRSA and all comprised mecA gene. The resistance pattern of MRSA strains to aminoglycoside antibiotics were: gentamicin 136 (84.5%); amikacin 125 (77.6%); kanamycin 139 (86.3%); tobramycin 132 (82%); and neomycin 155 (96.3%). The frequency of aac(Ia)-2, aph(3)-IIIa, and ant(4')-Ia genes among MRSA strains, were 64%, 42% and 11.8% respectively. In conclusion, as MRSA strains are of great concern in human infections, the results of present study could provide a useful resource for health sectors for choosing appropriate antibiotics for the effective treatment of infections due to MRSA strains.

<p>Characterization of <em>SCCmec</em>, <em>Spa</em> Types and Multidrug Resistant of Methicillin-Resistant <em>Staphylococcus aureus</em> Isolates in Ahvaz, Iran</p>

“…16 A previous study on MRSA in Khuzestan province revealed a dramatic annual increase in the proportion of isolates resistant to methicillin during the recent years, rising from 60% in 2017 and 2018 to a peak of 77% in 2019. [19][20][21][22] Such differences in the prevalence of MRSA infections in our region might reflect the fact that in these areas, different policies are considered for infection control and other factors. 23 There is a continuous increase in the global prevalence of MRSA in European countries.…”

Highly Resistant Staphylococcus aureus Isolated from Patients Attending a Tertiary Hospital, South Western Uganda

“…this is higher than 47.8% previously reported in Iran [40]. A resistance rate of 84.5% reported in the Sub Himalayan Region of India [41], reflects and increasing resistance nature of MRSA towards aminoglycosides. Similarly, the report indicates Tetracycline resistance rate of 80.7%, which is much higher than previous reports from Tehran (61%) [42].…”

Prognostic Parameters of the Susceptibility of Staphylococcus Spp. To Aminoglycosides and Doxycycline

“…Therapeutic approaches in patients with severe burns requires use of antibacterial drugs [18][19][20]. Opportunistic microorganisms such as S. aureus, which are the leading causative agents of opportunistic infections, are an important problem nowadays as these microorganisms developed resistance to methicillin [21] and some other antibiotics such as aminoglycosides and tetracyclines due to their uncontrolled used in medicine [1,2,4,12,13]. In such conditions analytical mathematical prediction of the susceptibility level based on the data from dynamic microbiological investigation of the S. aureus susceptibility to staphylococci and doxycycline is considered important in the effective assessment of the feasibility of alternative use of these drugs in patients with severe burns [14].…”

“…Despite exponential decrease of the S. aureus susceptibility in 2014-2017 predictive curve indicated an increase of susceptibility in the nearest future. Determined differences in the predicted tendencies of S. aureus susceptibility to various aminoglycosides can be in the directly dependent on the genetically predetermined mechanisms of different resistance genes expression by the microorganism to the drugs of this group [12,[23][24][25].…”

“…Investigation of new antimicrobial drugs for the treatment of infectious complications caused by S. aureus is relevant nowadays. Investigation of the prognostic parameters of the susceptibility to different antibiotics of different clinical isolates of Staphylococcus aureus, that are determined in patients with severe burns, is very important step in the improvement of antimicrobial means against resistant strains of this causative agent, because resistance of MRSA to aminoglycosides and tetracyclines is known [7][8][9][10][11][12][13][14].…”