Drug resistance ofEnterococcus faeciumclinical isolates and the conjugative transfer of gentamicin and erythromycin resistance traits

Abstract

Drug resistance and the transferability of resistance were examined in 218 Enterococcus faecium clinical isolates obtained from in-patients of a Japanese university hospital between 1990 and 1999. One hundred and sixty one isolates (73.9%) were drug-resistant and 127 (58.2%) isolates were resistant to two or more drugs. Vancomycin resistant E. faecium (VRE) was not isolated. The transferability of drug-resistance to an E. faecium strain was examined by broth or filter mating. Six (12.5%) of the 48 gentamicin resistance traits, and fifty (50%) of the 101 erythromycin resistance traits were transferred by filter mating. The gentamicin resistance traits of five isolates and the erythromycin resistance traits of four isolates were transferred to the recipient strains by both broth mating and filter mating at a frequency of about 10(-6) and 10(-5) per donor cell, respectively. The five gentamicin resistant strains were shown to harbor pMG1-like plasmids on the basis of their Southern hybridization with pMG1 (65.1 kbp, Gm(r)), which transfers efficiently between enterococci by broth mating. Each of the four erythromycin resistant transconjugants obtained by broth mating harbored a large conjugative plasmid (more than 100 kbp). The plasmids showed no homology with well-characterized enterococcal conjugative plasmids such as pAD1, pPD1, pAM(beta)1, pIP501 and pMG1 by Southern hybridization. Of the erythromycin resistance traits that transferred only by filter mating, it was found that the erythromycin resistance trait was conferred by a 47-kbp transposable element that transferred from the chromosome of the donor strain to different sites within the pheromone responsive plasmid pAD1 (60 kbp) of the recipient strain, suggesting that the erythromycin resistance trait was encoded on a conjugative transposon, which was named Tn950.

Determination of Virulence Factors in Clinical Multidrug Resistance Enterococci Isolates at Southeast of Iran

“…The results was indicated 18 out total eighty five isolates are related to MDRs, and the majority of MDR isolates were associated with E. faecium species (16,17). Recent studies also described a gradual increasing of MDR isolates throughout nosocomial infections (16,18). Different reports pointed out two major enterococci species associated with hospital infections.…”

Physico-Chemical Properties and Microbiological Quality of Borehole Water in Four Crowded Areas of Benin City, Nigeria, During Rainfalls

“…Contaminated potable drinking water has severe health implications on humans, including diseases of the gastrointestinal tract and bacteraemia (10). Moreover, clean potable drinking water contaminated with toxic chemicals can cause acute and chronic health effects (11,12).…”

Identification of Inhibitory Effect on Streptococcus mutans by Oleanolic Acid

“…Horiuch research group suggested that the compounds are not active on Gram-negative bacterium, including E. coli, P. aeruginosa and Serratia marcescens, due to the existence of the outer membrane which is equipped with several multidrug efflux pumps [6]. Of the Gram-positive strains tested in this study, E. faecalis and E. faecium are commonly isolated from human infections and resistant to many antimicrobial agents in many cases [19]. Listeria monocytogenes is a clinically important human pathogen causing listeriosis with a high fatality rate [21] and has been reported as an antimicrobial-resistant strain [14].…”