Plasmid-mediated resistance to antibiotic synergism in enterococci.

نویسندگان

  • D J Krogstad
  • T R Korfhagen
  • R C Moellering
  • C Wennersten
  • M N Swartz
چکیده

Mating experiments have shown that high-level resistance (minimal inhibitory concentration greater than 2,000 microgram/ml) to streptomycin and kanamycin, and resistance to penicillin-streptomycin and penicillin-kanamycin synergism are transferable by conjugation from resistant clinical isolates of enterococci to a sensitive recipient strain. Cesium chloride-ethidium bromide ultracentrifugation revealed a satellite (plasmid) band in resistant clinical isolates and the transconjugant strains but not in the sensitive recipient. Examination of these satellite bands by agarose gel electrophoresis and electron microscopy demonstrated a common plasmid with a weight of 45 megadaltons. Novobiocin treatment of a resistant clinical isolate produced simultaneous loss of high-level resistance to streptomycin and kanamycin, and of resistance to penicillin-aminoglycoside synergism. These results suggest that (a) high-level resistance to streptomycin and kanamycin among some clinical isolates of enterococci is associated with a 45 megadalton plasmid, and (b) the same plasmid is also responsible for the resistance to penicillin-aminoglycoside synergism observed in these strains.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Evaluation of Virulence Factors and Plasmid-Related Transmissibility among Different Isolates of Enterococci

The incidence of virulence factors among 114 Enterococcus faecalis and 35 Enterococcus faecium strains from different clinical specimens were compared with those isolated from control groups. A few of the isolates expressed two or more of the following traits simultaneously: hemolysin, aggregation substance, gelatinase, DNase, hemagglutinin and antibiotic resistance. The frequencies of hemolysi...

متن کامل

بررسی ژن aac(6')Ie-aph(2″)Ia در میان سویه های بالینی انتروکوک و تشخیص سویه های مقاوم به سطح بالای جنتامایسین

Introduction & Objective: Enterococci have emerged as the leading nosocomial pathogens. In addition to natural resistance to many agents, enterococci have also developed plasmid- and transposon-mediated resistance to high concentrations of aminoglycosides. High-level gentamicin resistance (HLGR) of enterococci results in the failure of drug synergism with an aminoglycoside plus cell-wall-acti...

متن کامل

Mechanism of resistance to antibiotic synergism in enterococci.

Enterococci exhibit two types of resistance to streptomycin. Moderately high-level resistance is observed in most naturally occurring strains and can be overcome by simultaneous exposure to penicillin. In addition, very high-level resistance is found in those strains against which penicillin plus streptomycin fail to produce synergism in vitro. To study the mechanism of streptomycin resistance ...

متن کامل

PLASMID MEDIATED METAL AND ANTIBIOTIC RESISTANCE IN PSEUDOMONAS AERUGINOSA STRAINS ISOLATED FROM BURN PATIENTS

Pseudomonas aeruginosa is a leading cause of bum infections, and antibiotic- resistant strains of this bacterium are emerging due to extensive application of antibiotics in the bum unit of hospitals. In this study 50 strains of P. aeruginosa were isolated from bum patients infected with this micro-organism in the bum unit of a general hospital in Kerman, Iran over one year [May 1999-ApriI20...

متن کامل

Studies of cephalothin: aminoglycoside synergism against enterococci.

Combinations of cephalothin and aminoglycoside antibiotics are not currently used in the therapy of serious enterococcal infections, because clinical trials of these combinations have been unsuccessful. Studies of 28 enterococci isolated from patients with enterococcal bacteremia suggested three possible mechanisms for this in vivo antibiotic failure: (i) a relatively high level of resistance t...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of clinical investigation

دوره 61 6  شماره 

صفحات  -

تاریخ انتشار 1978