The prevalence of aminoglycoside-modifying enzyme and virulence genes among enterococci with high-level aminoglycoside resistance in Inner Mongolia, China

ABSTRACT This study highlights the prevalence of aminoglycoside-modifying enzyme genes and virulence determinants among clinical enterococci with high-level aminoglycoside resistance in Inner Mongolia, China. Screening for high-level aminoglycoside resistance against 117 enterococcal clinical isolates was performed using the agar-screening method. Out of the 117 enterococcal isolates, 46 were selected for further detection and determination of the distribution of aminoglycoside-modifying enzyme-encoding genes and virulence determinants using polymerase chain reaction -based methods. Enterococcus faecium and Enterococcus faecalis were identified as the species of greatest clinical importance. The aac(6')-Ie-aph(2")-Ia and ant(6')-Ia genes were found to be the most common aminoglycoside-modifying enzyme genes among high-level gentamicin resistance and high-level streptomycin resistance isolates, respectively. Moreover, gelE was the most common virulence gene among high-level aminoglycoside resistance isolates. Compared to Enterococcus faecium, Enterococcus faecalis harbored multiple virulence determinants. The results further indicated no correlation between aminoglycoside-modifying enzyme gene profiles and the distribution of virulence genes among the enterococcal isolates with high-level gentamicin resistance or high-level streptomycin resistance evaluated in our study.

Endocarditis por Enterococcus gallinarum, a propósito de un caso / Endocarditis due to Enterococcus gallinarum, in relation to a case

La endocarditis infecciosa por Enterococcus gallinarum no es muy común, actualmente se reportan pocos casos. Los Enterococcus spp. son bacterias que se encuentran en el tracto intestinal de humanos, mamíferos y aves; así como el tracto genital femenino de los seres humanos. Encontrar éstos microorganismos en sangre puede indicar la presencia de contaminación, en particular si tomamos en cuenta que sobreviven a condiciones extremas de clima (temperatura y pH).1 Enterococcus gallinarum es parte de la microbiota normal del tracto gastrointestinal, pero también puede encontrarse en enfermos hospitalizados, particularmente por periodos prolongados así como en alimentos. La bacteriemia causada por éstos afectan generalmente a pacientes inmunocomprometidos o con enfermedades crónicas debilitantes y/o degenerativas.2 La bacteriemia se define como la presencia de microorganismos en sangre, comprobado por 2 o más hemocultivos; una higiene oral inadecuada puede conllevar a inflamación y ulceración gingival; así mismo la manipulación de procedimientos odontológicos que impliquen procedimientos invasivos de mucosa gingival o lesiones en la misma como un cepillado dental que cause sangrado de la mucosa oral.3 Usualmente la infección de E. gallinarum se acompaña de una infección polimicrobiana. Últimamente se ha visto un aumento de enfermedades adquiridas en la comunidad de especies de Enterococcos spp resistentes hacia distintos fármacos, pero en especial a la Vancomicina, debido al uso indiscriminado de la avoparcina, un antimicrobiano del grupo de los glicopéptidos, que se usa en la industria y crianza de animales de granja.1 (AU)

Prevalence and phenotypic characterization of Enterococcus spp. isolated from food in Brazil

We evaluated the frequency of enterococci from food and found 95.2% of positivity, being E. faecium and E. faecalis the most frequent species. High-level streptomycin resistance was observed, as well as gelatinase and hemolysis activity, showing the potential role of environmental strains as reservoir of virulence and resistance traits.

Antimicrobial resistance in enterococci

Enterococci have emerged as a major nosocomial pathogen and as an ever-increasing problem in antimicrobial resistance. They are ubiquitous in the intestinal flora of humans and animals and inherently resistant to a wide array of antimicrobial agents, and, more alarmingly, they seem to have a potential facility for acquiring new resistance determinants, including beta-lactamase production, high-level resistance to aminoglycosides, and recently, glycopeptide resistance. Collectively, all of these properties make enterococci one of most difficult nosocomial pathogens to treat and control today. The purpose of this review was to examine the epidemiology, the mechanisms, and laboratory detection of resistance of enterococci to the two major groups of antibiotics: aminoglycosides and glycopeptides.