Aminoglycoside-resistant staphylococci in Greece: prevalence and resistance mechanisms

Abstract

To determine the prevalence of aminoglycoside-modifying enzymes (AMEs) genes and the rate of resistance to amikacin, gentamicin, kanamycin and tobramycin a total of 1228 gene. The rate of resistance as determined by disk diffusion method and Etest was 48.2% for kanamycin, 48.2% for amikacin, 12.9% for tobramycin and 6.3% for gentamicin. MRSA were more resistant than MSSA (92.7% resistant to amikacin and kanamycin, 25% to tobramycin and 12.3% to gentamicin versus 2.6% to amikacin and kanamycin and 0.3% to tobramycin respectively). Vitek 2 P549 card failed to characterize all S. aureus that carried the aph(3')-IIIa gene. Significant differences on the rate of resistance and distribution of AME genes were observed among S. aureus strains originating in different hospitals. On the other hand, 42.8% of S. epidermidis, all methicillin-resistant, carried any AMEs genes; 70% of the positive strains carried the aac(6')-Ie-aph(2") gene in combination with both ant(4')-Ia and aph(3')-IIIa genes, 18% carried the aac(6')-Ie-aph(2") gene with ant(4')-Ia, while, 12% carried the aac(6')-Ie-aph(2") gene with aph(3')-IIIa. The rate of resistance to all aminoglycosides tested was 42.8%; 100% concordance of susceptibility results was observed between those of disk diffusion method, Etest and Vitek 2 P549 card. No significant differences on the rate of resistance or the AME gene distribution among different geographic regions were observed among S. epidermidis strains. These results suggest an alarming rate of aminoglycoside-resistant staphylococciin Greece and the necessity for a continuous surveillance.

Virulence and the presence of aminoglycoside resistance genes of Staphylococcus haemolyticus strains isolated from clinical specimens

“…The aph (3′)- III was found in 43 % and interpreted as the most frequently carried AME genes. Liakopoulos et al ( 2011 ) suggested that the aph(3′) - III was also the most prevalent AME gene among Staphylococcus aureus and CNS isolated in Greece. In contrast, Ida et al ( 2001 ) revealed that the aph (3′)- III genes were carried only by 8.9 % strains originated from Japan, whereas the most prevalent was the ant (4′)- Ia gene.…”

Prevalence of antibiotic resistance in multi-drug resistant coagulase-negative staphylococci isolated from invasive infection in very low birth weight neonates in two Polish NICUs

“…50% of CNS isolates there existed a correlation between the phenotype of amikacin resistance and the genotype [13]. According to recommendations of EUCAST (2012) [10], the isolates demonstrating gentamicin resistance are to be treated as having a general aminoglycoside resistance with the exception of streptomycin, as this one is most probably coded by the aac(6′)/aph(2″) gene the product of which modifies antibiotics such as gentamicin, kanamycin, tobramycin and amikacin [22]. The phenotype of gentamicin resistance, despite the missing aac(6′)/aph(2″) gene, may be caused by the presence of other genes coding aminoglycoside resistance which were not determined in the method used.…”

Antimicrobial Susceptibility and Enterotoxin-Encoding Genes inStaphylococcusspp. Recovered from Kitchen Equipment from a University Hospital in Rio de Janeiro, Brazil

“…35 CoNS have been identified as a reservoir for resistance determinants, including genes encoding aminoglycoside-modifying enzymes; moreover, the conjugal transfer of resistance determinants among S. epidermidis and S. aureus leads to the rapid spread of these determinants in the hospital environment. 36 Seven strains of CoNS were found resistant in both AST and MIC testing to gentamicin, and all strains showed the aac(6¢)-aph(2¢¢) gene. S. caprae and S. warneri were the most frequent species in our study and showed those characteristics.…”