Prevalence of high-level aminoglycoside resistance and genes encoding aminoglycoside-modifying enzymes in Enterococcus faecalis and Enterococcus faecium isolated in a university hospital in Tokyo.

We examined the prevalence of HLAR by disk diffusion method, carriage of genes for aminoglycoside-modifying enzymes by PCR, and production of β-lactamase by nitrocefin-based test in Enterococcus faecalis and Enterococcus faecium isolated from patients at a university hospital in Tokyo in 2010. Of the 100 E. faecalis isolates analyzed, 30 isolates had high-level resistance (HLR) to gentamicin and 22 isolates had HLR to streptomycin. Of the 40 E. faecium isolates analyzed, nine isolates had HLR to gentamicin and nine isolates had HLR to streptomycin. Of the 39 gentamicin-HLR enterococcal isolates, 24 isolates were non-HLR to streptomycin. All 39 isolates with HLR to gentamicin as well as 19 of 101 without HLR carried aac(6')-Ie-aph(2'')-Ia. Carriage of ant(6')-Ia was confirmed in 25 of 31 streptomycin-HLR isolates. Production of β-lactamase was documented in none of the E. faecalis and E. faecium isolates. Whole-genome sequencing analysis revealed that all but one E. faecalis isolates that carried aac(6')-Ie-aph(2'')-Ia and ant(6')-Ia belonged to sequence type (ST) 4 (n=8), ST16 (n=4), or ST179 (n=9). Nevertheless, most of the pairs of isolates had > 10 single-nucleotide polymorphisms even among the isolates of the same ST. PMID: 32611969 [PubMed - as supplied by publisher]
Source: Japanese Journal of Infectious Diseases - Category: Infectious Diseases Authors: Tags: Jpn J Infect Dis Source Type: research