Letters to the EditorVancomycin-dependent Enterococcus faecalis
References (5)
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High level vancomycin resistant enterococci causing hospital infections
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Transferable vancomycin and teicoplanin resistance in
Enterococcus falcium. Antimicrob Ag & Chemother
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Cited by (30)
Vancomycin dependent Enterococcus: an unusual mutant?
2019, PathologyEmergence of vancomycin-dependent enterococci following glycopeptide therapy: Case report and review
2009, Pathologie BiologieDes épidémies d’entérocoques résistants à la vancomycine ont été décrites en France depuis trois ans. Nous rapportons un cas d’émergence d’une souche d’entérocoque dépendante de la vancomycine à la suite d’un traitement par glycopeptide.
Une souche d’Enterococcus faecium dépendante de la vancomycine pour sa croissance a été isolée à partir des selles d’une patiente transplantée hépatique porteuse d’entérocoque résistant à la vancomycine avant la greffe, puis traitée par vancomycine pour une infection à Staphylococcus aureus résistant à la méticilline. La souche résistante et la souche dépendante ont été typées par électrophorèse en champ pulsé. Le gène ddl codant pour la d-Ala : d-Ala ligase a été amplifié par PCR et séquencé.
La souche dépendante a été isolée initialement sur un milieu sélectif contenant de la vancomycine et n’a pu être obtenue en subculture qu’en présence de cet antibiotique. La souche résistante et la souche dépendante possédaient le gène vanA et présentaient le même profil de restriction par électrophorèse en champ pulsé. La dépendance à la vancomycine était associée à la délétion d’une paire de bases dans la séquence du gène ddl provoquant un décalage du cadre de lecture et l’apparition d’un codon stop prématuré.
Les prélèvements cliniques des patients porteurs d’entérocoque résistant à la vancomycine et traités par glycopeptide doivent être cultivés sur des milieux contenant de la vancomycine afin de détecter l’émergence de souches dépendantes.
Outbreaks of vancomycin-resistant enterococci have been increasingly reported in France over the last three years. We report here, the emergence of a vancomycin-dependent enterococci isolate following glycopeptide therapy.
An Enterococcus faecium isolate that required vancomycin for growth was cultured from the stools of a liver transplant recipient who was colonised with vancomycin-resistant enterococci and who received vancomycin treatment for methicillin-resistant Staphylococcus aureus infection. The resistant isolate and the dependent isolate were typed by pulsed-field gel electrophoresis. The sequence of the ddl gene coding for the d-Ala: d-Ala ligase was analysed.
The dependent isolate was primary cultured onto a vancomycin-containing screening medium and could not be subcultured in the absence of vancomycin. Both the resistant and dependent isolates harboured the vanA gene and they had the same DNA restriction pattern after pulsed-field gel electrophoresis. Dependence on vancomycin was associated with a 1-bp deletion in the d-Ala: d-Ala ligase gene leading to an early stop codon.
Cultures onto vancomycin-containing media are warranted for clinical specimens from patients, who are known to carry vancomycin-resistant enterococci and receive vancomycin therapy.
Occurrence and spread of antibiotic resistances in Enterococcus faecium
2003, International Journal of Food MicrobiologyEnterococci are the second to third most important bacterial genus in hospital infections. Especially Enterococcus (E.) faecium possesses a broad spectrum of natural and acquired antibiotic resistances which are presented in detail in this paper. From medical point of view, the transferable resistances to glycopeptides (e.g., vancomycin, VAN, or teicoplanin, TPL) and streptogramins (e.g., quinupristin/dalfopristin, Q/D) in enterococci are of special interest.
The VanA type of enterococcal glycopeptide resistance is the most important one (VAN-r, TPL-r); its main reservoir is E. faecium. Glycopeptide-resistant E. faecium (GREF) can be found in hospitals and outside of them, namely in European commercial animal husbandry in which the glycopeptide avoparcin (AVO) was used as growth promoter in the past. There are identical types of the vanA gene clusters in enterococci from different ecological origins (faecal samples of animals, animal feed, patients in hospitals, persons in the community, waste water samples). Obviously, across the food chain (by GREF-contaminated meat products), these multiple-resistant bacteria or their vanA gene clusters can reach humans. In hospital infections, widespread epidemic-virulent E. faecium isolates of the same clone with or without glycopeptide resistance can occur; these strains often harbour different plasmids and the esp gene. This indicates that hospital-adapted epidemic-virulent E. faecium strains have picked up the vanA gene cluster after they were already widely spread. The streptogramin virginiamycin was also used as feed additive in commercial animal husbandry in Europe for more than 20 years, and it created reservoirs for streptogramin-resistant E. faecium (SREF). In 1998/1999, SREF could be isolated in Germany from waste water of sewage treatment plants, from faecal samples and meat products of animals that were fed virginiamycin (cross resistance to Q/D), from stools of humans in the community, and from clinical samples. These isolations of SREF occurred in a time before the streptogramin combination Q/D was introduced for therapeutic purposes in German hospitals in May 2000, while other streptogramins were not used in German clinics. This seems to indicate that the origin of these SREF or their streptogramin resistance gene(s) originated from other sources outside the hospitals, probably from commercial animal husbandry. In order to prevent the dissemination of multiple antibiotic-resistant enterococci or their transferable resistance genes, a prudent use of antibiotics is necessary in human and veterinary medicine, and in animal husbandry.
Modulation of the intestinal ecosystem by probiotics and lactulose in children during treatment with ceftriaxone
2001, Current Therapeutic Research - Clinical and ExperimentalBackground: The value of oral bacteriotherapy during antibiotic treatment is a much debated subject. Comparative studies on the effects of different probiotics on the intestinal ecosystem are lacking.
Objective: Six different commercially available preparations of probiotics and 1 prebiotic (lactulose) were compared to establish whether their action prevented or corrected imbalances in the intestinal ecosystem (dysbiosis) during parenteral therapy with ceftriaxone.
Methods: Fifty-one children (25 female, 26 male; mean age, 5.1 years) admitted to the hospital for febrile respiratory tract infections were treated. Ceftriaxone 50 mg/kg per day was administered parenterally alone (therapy 1) or with 1 of the following probiotic/prebiotic preparations: Saccharomyces boulardii (therapy 2); Enterococcus species (therapy 3); lactulose (therapy 4); Lactobacillus casei GG (therapy 5); Lactobacillus rhamnosus, Lactobacillus bifidus, and Lactobacillus acidophilus (therapy 6); Bifidobacterium bifidum and L acidophilus (therapy 7); or a mixture of various lactobacilli and bifidobacteria at high concentrations (therapy 8).
Intestinal microflora were evaluated by standard microbiologic methods and by biochemical assays on fecal samples collected before and after treatment.
Results: Ceftriaxone induced a decrease in Escherichia coli and lactobacilli counts and an increase in cocci and clostridia counts. Partial protection of the intestinal ecosystem (eubiosis) was achieved with therapies 6, 7, and 8, which contained different combinations of Lactobacillus and Bifidobacterium species. Probiotics containing lactobacilli were more active than the older Saccharomyces and Enterococcus preparations. The newer probiotics reduced β-galactosidase, β-glucosidase, and β-glucuronidase levels. Increased fecal β-lactamase activity was observed in 60% of patients treated with ceftriaxone alone and 75% of those treated with ceftriaxone and S boulardii. A lower incidence of beta-lactamase-positive samples (30%–40%) was observed with therapy 7 and therapy 8.
Conclusions: In this preliminary study, probiotics containing multiple species of lactobacilli and bifidobacteria administered at high concentration (20 billion to 360 billion per day) were more effective in preventing dysbiosis induced by ceftriaxone treatment than were other preparations studied. Probiotic therapy may need to be maintained for several days after discontinuation of antibiotic treatment to adequately restore balance to the intestinal ecosystem.
Acquired and intrinsic glycopeptide resistance in enterococci
2000, International Journal of Antimicrobial AgentsEnterococci are Gram-positive cocci responsible for severe human infections, such as endocarditis, meningitis, and septicemia and constitute an increasingly frequent cause of nosocomial infections. Enterococci are resistant to nearly all classes of drugs including, since 1986, glycopeptides. Vancomycin and teicoplanin act by blocking cell wall formation and resistance is due to synthesis of modified late peptidoglycan precursors. Glycopeptide resistance can be intrinsic or acquired and strains may be resistant to vancomycin and teicoplanin, or to vancomycin only. Five types of glycopeptide resistance and their biochemical mechanisms have been described in enterococci. Clinical isolates that are dependent on vancomycin for growth have been isolated. Data suggest a dual origin for resistance: glycopeptide-producing organisms or enterococcal species intrinsically resistant to these drugs.
Nuances in antimicrobial susceptibility testing for resistant gram-positive organisms
2000, Antimicrobics and Infectious Diseases Newsletter