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PubMedDate not supplied

Absence of high-level vancomycin resistance in enterococci isolated from meat-processing facilities.

Enterococci isolated from packaging areas of meat-processing facilities that produce ready-to-eat meat products were examined for high-level vancomycin resistance. A total of 406 enterococci isolates from the plants' packaging areas were examined for vancomycin resistance. High-level vancomycin resistance was not demonstrated in any enterococci isolated from 12 meat-processing plants.

Anti-Bacterial Agents↗

PubMed2002

Antecedent treatment with different antibiotic agents as a risk factor for vancomycin-resistant Enterococcus.

We conducted a matched case-control study to compare the effect of antecedent treatment with various antibiotics on subsequent isolation of vancomycin-resistant Enterococcus (VRE); 880 in-patients; 233 VRE cases, and 647 matched controls were included. After being matched for hospital location, calendar time, and duration of hospitalization, the following variables predicted VRE positivity: main admitting diagnosis; a coexisting condition (e.g., diabetes mellitus, organ transplant, or hepatobiliary disease); and infection or colonization with methicillin-resistant Staphylococcus aureus or Clostridium difficile within the past year (independent of vancomycin treatment). After controlling for these variables, we examined the effect of various antibiotics. Intravenous treatment with third-generation cephalosporins, metronidazole, and fluoroquinolones was positively associated with VRE. In our institution, when we adjusted the data for temporo-spatial factors, patient characteristics, and hospital events, treatment with third-generation cephalosporins, metronidazole, and fluoroquinolones was identified as a risk factor for VRE. Vancomycin was not a risk factor for isolation of VRE.

Adolescent↗

PubMed2003

Hemolytic and nonhemolytic vancomycin-resistant Enterococcus faecalis isolated from beef imported to Malaysia.

Twenty-two strains of vancomycin-resistant Enterococcus faecalis were isolated from 9 (6%) of 150 samples of frozen beef and beef products imported to Malaysia. The isolates were obtained from eight samples of beef and one sample of minced beef patty. No E. faecalis was isolated from frankfurters. Twelve of the 22 isolates (54.5%) were beta-hemolytic, and all isolates harbored the vanA gene. All vancomycin-resistant isolates were also resistant to streptomycin, erythromycin, kanamycin, bacitracin, ceftazimide, gentamycin, tetracycline, nalidixic acid, and teicoplanin; 95.4% were resistant to trimethoprimsulfamethoxazole; 68.8% were resistant to chloramphenicol; and 41% were resistant to ampicillin and penicillin. Small plasmids ranging in size from 1.5 to 5.8 kb were detected in 8 (36.4%) of 22 strains. The 22 isolates were classified into 20 random amplified polymorphic DNA types. Isolates were divided into two groups, each containing subclusters, that may reflect their clonal lineages. It is concluded that several clones of vancomycin-resistant E. faecalis are represented in the isolates obtained from beef imported to Malaysia.

Animals↗

PubMed2001

Prevalence of colonisation and resistance patterns of vancomycin-resistant enterococci in healthy, non-hospitalised persons in Switzerland.

In order to obtain data about the prevalence and the resistance profiles of vancomycin-resistant enterococci (VRE) in the community, we investigated fecal samples of employees (n = 1026) from food processing companies of different Swiss cantons. The susceptibility of the isolated VRE-strains against penicillin, ampicillin, tetracyclin, ciprofloxacin, chloramphenicol, streptomycin and gentamicin as well as the minimal inhibitory concentrations (MIC) for vancomycin and teicoplanin were determined by agar diffusion and microbroth dilution, respectively. The type of vancomycin-resistance (vanA, vanB, vanC1, -C2 or -C3) was confirmed by polymerase chain reaction (PCR). A ratio of 50 samples out of 1026 (4.9%) was found VRE-positive, all of the isolated strains carried the vanA-resistance gene. Compared to recent publications from other European countries, these results represent a rather high prevalence of VRE-carriers in the community.

Anti-Bacterial Agents↗

PubMed2000

Update on vancomycin resistance.

Enterococci can be responsible for severe infections such as endocarditis, meningitis and septicaemia and are one of the most important causes of nosocomial infections. Resistance in enterococci concerns many classes of antibiotics including, since 1986, glycopeptides. These antibiotics act by blocking cell wall formation, and resistance is due to synthesis of modified peptidoglycan precursors. Resistance can be acquired or intrinsic 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. Furthermore, strains that are dependent on vancomycin for growth have been isolated from clinical samples. Data suggest that resistance could originate in glycopeptide-producing organisms or in enterococcal species intrinsically resistant to these antibiotics.

Anti-Bacterial Agents↗

PubMed2001

Gastrointestinal colonisation of vancomycin-resistant enterococcus in a Singapore teaching hospital.

Vancomycin-resistant enterococcus (VRE) has become an important nosocomial pathogen in many countries but is still rare in Singapore. A study was conducted from January to March 1997 at a 900-bed teaching hospital to determine the prevalence of intestinal colonisation of VRE in the patient population. A total of 299 consecutive stool specimens received by the microbiology laboratory for routine testing were plated onto two different selective media for comparison. VRE isolated were phenotypically characterised using minimum inhibitory concentrations (MICs) to vancomycin and teicoplanin and then typed using pulsed-field gel electrophoresis (PFGE) with Smal digestion of DNA. VRE were detected in the stool of 35 patients (12.3%). This group consisted of four isolates with VanB (one Enterococcus faecalis and three E. faecium) and 31 isolates with VanC (30 E. casseliflavus and one E. gallinarum). Two patients (0.7%) carried isolates (both VanB) with high level resistance to vancomycin (MIC > or = 256 microg/ml) while the rest had isolates of low level resistance (MIC = 8 microg/ml). Except for isolates from the same patients, PFGE patterns were diverse, suggesting that the VRE isolates were genotypically different and possibly introduced from many sources. This study demonstrates that VRE colonisation is not uncommon in the Singapore patient population.

Adult↗

PubMedDate not supplied

Colonization with vancomycin-resistant enterococci (VRE) in intensive care unit patients in Cordoba City, Argentina.

The purpose of this study was to determine the prevalence of colonization with vancomycin-resistant enterococci (VRE) among intensive care unit (ICU) patients in a hospital in Córdoba, Argentina. We collected 235 rectal swab specimens from 147 ICU patients. Resistance to vancomycin was screened with the disk diffusion method, and MICs were determined with the E-test method. Vancomycin-resistant genotypes were determined by PCR. The VRE strains were isolated from 18/147 patients (12.2%). The isolates were identified as Enterococcus faecium (94.4%), and Enterococcus gallinarum (5.6%). PCR showed that the E. faecium strains carried the vanA gene, and the E. gallinarum strain carried the vanC1 gene. Our study indicated that at least 12.2% of ICU patients were VRE carriers.

Argentina↗

PubMed1984

Staphylococcal CNS infections treated with vancomycin and rifampin.

Three children had staphylococcal infections of the CNS. In two cases the organisms were resistant to methicillin sodium. Each case was treated with a combination of vancomycin hydrochloride and rifampin; in one instance vancomycin alone had been unsuccessful. The addition of rifampin resulted in prompt clinical and bacteriologic resolution. Satisfactory levels of rifampin were achieved by administering the drug either orally or intravenously, and in one patient oral administration of rifampin produced assayed levels in subdural pus many times that required for minimal bactericidal activity. Combination therapy with vancomycin and rifampin is recommended for staphylococcal infections of the CNS.

Adolescent↗

PubMed1997

Postoperative contamination after using vancomycin and gentamicin during phacoemulsification.

OBJECTIVE: To investigate if the addition of vancomycin and gentamicin to the irrigating solutions during phacoemulsification with lens implantation reduces the incidence of positive postoperative intraocular cultures. DESIGN: Two-part double-masked, placebo-controlled, randomized clinical trial. PATIENTS: In the preliminary study, intracameral antibiotic concentrations were measured immediately after surgery (in 10 eyes) and 2 hours after surgery (in 10 eyes) in patients treated with antibiotics. In the primary study, 120 eyes underwent uncomplicated surgery. The treatment group and the placebo group were composed of 60 eyes each. INTERVENTION: The treatment group received vancomycin, 20 micrograms/mL, and gentamicin, 8 micrograms/mL, in the irrigating fluid. The placebo group received only irrigating fluid. All patients in the primary study underwent anterior chamber aspiration following surgery, and culturing was performed 2 hours later. MAIN OUTCOME MEASURE: Identification and quantification of positive cultures in thioglycolate broth and chocolate agar. RESULTS: In the preliminary study, the half-life of both intraocular antibiotics was less than 2 hours. In the primary study, intraocular aspirates yielded positive cultures in 3 specimens (5.0%) in the antibiotic-treated group and in 7 specimens (12.0%) in the placebo group. CONCLUSIONS: Although we found a higher rate of positive postoperative cultures in the placebo group (odds ratio = 2.51), 2 hours of contact between the antibiotic solution and bacteria did not produce results that reached statistical significance (P =.18) to support adding vancomycin and gentamicin to the irrigating solutions during phacoemulsification. Further studies are needed to evaluate the clinical implications of using antibiotics in irrigating solutions.

Adult↗

PubMed1984

Vancomycin dosage in pediatrics reconsidered.

Vancomycin hydrochloride levels were studied in 44 children (age range, 10 days to 10 years). These children received doses of vancomycin within current recommendations. Major variations in vancomycin levels were demonstrated in similar age groups and dosage regimens. For patients in the first month of life, second month of life, and older ages, respectively, 70%, 39%, and 30% of the peak determinations and 53%, 50%, and 23% of the trough determinations were greater than the desired level. Potentially toxic levels were found in eight patients.

Age Factors↗

PubMed1986

Vancomycin pharmacokinetics in small, seriously ill infants.

Twenty vancomycin pharmacokinetic studies were performed on 17 small infants who were receiving the antibiotic for treatment of documented infections. Fourteen patients were less than or equal to 41 weeks' postconception. In this group there was no statistical difference in mean elimination rate, volume of distribution, or clearance between neonates and infants 4 to 8 weeks of age. However, they had significantly lower clearance and prolonged mean beta-half-life than infants who were 3 to 6 months old (greater than 43 weeks' postconception). Vancomycin clearance was directly related to postconceptional age by linear regression analysis. beta-Half-life was influenced by the weight of the patient, volume of distribution, and gestational age. In view of the interpatient variability observed in the prematurely born infants, pharmacokinetic studies should be performed to determine the appropriate dose and intervals in vancomycin therapy.

Age Factors↗

PubMed1996

Surgical Infection Society position on vancomycin-resistant Enterococcus.

The risk of transfer of vancomycin resistance to staphylococci is a real possibility and has been achieved in the laboratory. Prolonged colonization occurs with vancomycin-resistant Enterococcus (VRE), and many more patients are colonized than infected. The failure to identify, isolate, and adhere to infection control measures when caring for VRE-colonized patients dooms to failure any means to control its spread. Control of vancomycin use alone is unlikely to greatly affect the number of patients at risk for VRE colonization. The global spread of VRE may be impossible to stop, but infection control measures are the most important line of defense inside hospitals.

Anti-Bacterial Agents↗

PubMed2002

Enantioseparation of amino acid derivatives by capillary zone electrophoresis using vancomycin as chiral selector.

The separation of racemic derivatized amino acids (N-acetyl) into their enantiomers was achieved using capillary zone electrophoresis employing vancomycin as a chiral selector. Due to the strong absorption properties of the chiral selector at the low wavelengths used, the partial-filling countercurrent method was adopted in order to improve method sensitivity. In the separation system studied, the chiral selector filled only a part of the capillary and, due to the appropriate selection of the pH, was moving in the opposite direction of the analytes keeping the detector free from absorbing compounds. The effect of several experimental parameters on the enantioresolution of analytes was studied, e.g., vancomycin concentration (0-5 mM), pH of the background electrolyte (pH 4-7), capillary temperature (15-35 degrees C), and the presence of an organic modifier in the run buffer (methanol or ethanol or n-propanol). N-Acetyl glutamic acid, serine, cystine, tyrosine, and proline were all baseline-resolved into their enantiomers and the enantioresolution factor (R(s)) was increased by raising the vancomycin concentration. pH 4 allowed the baseline resolution of the five studied analytes in the presence of 2.5 mM of chiral selector and an increase in pH caused a decrease of R(s).

Amino Acids↗

PubMed1991

The natural design of vancomycin family antibiotics to bind their target peptides.

The vancomycin family of antibiotics provide a rare opportunity among natural systems to study a molecular recognition process in which both the 'receptor' and the 'ligand' are relatively small molecules. Unlike the vast majority of antibiotics, in the vancomycin family the antibiotic performs the role of the receptor. All members of the family are covalently cross-linked heptapeptides that contain a variety of glycosidic modifications. Their site of action in bacterial cell walls is modelled by simple dipeptides and tripeptides. NMR experiments have been used to characterize the binding of these species through the study of both the complex and the free components. In unbound antibiotics conformational freedom is observed in regions of the molecule not severely restricted by covalent linkages. On binding of the ligand much of this conformational freedom is lost and the hydrophobic side chains of the antibiotics reside close to the intermolecular hydrogen-bonding interactions, thus shielding these interactions from the solvent. The charged amino groups of the N-terminus and disaccharide region of vancomycin are orientated not to optimize intermolecular electrostatic interactions but rather to retain solvation. This causes further hydrophobic faces to be presented to the ligand. Removal of saccharide units from the antibiotics leads to small losses in binding energy but may have considerable influence on the selectivity of the antibiotics. Specific dimerization through the non-ligand-binding faces of ristocetin is observed at millimolar concentrations. The geometry of the dimeric complex enables a close approach of the ligand carboxylate anion and the charged amino group of the novel sugar, ristosamine.

Amino Acid Sequence↗

PubMed2004

An automated analyzer for vancomycin in plasma samples by column-switching high-performance liquid chromatography with UV detection.

An automated analyzer for vancomycin in rat plasma by column-switching high-performance liquid chromatography (HPLC) with UV detection was developed. The method includes in-line extraction of vancomycin by ion-exchange cartridge column and a separation on a reversed-phase column with UV detection at 215 nm. Plasma samples were diluted by mobile phase solution and directly injected to HPLC. Vancomycin was quantitatively recovered from rat plasma samples. The separation was completed within 15 min. The calibration curve was linear over the range from 0.5 to 100 microg/mL with the detection and quantification limits of 0.5 microg/mL (2.5 ng on column; signal-to-noise ratio = 3). The values of precision in intra- and inter-day assays (n = 3) were less than 1.92 and 3.69%, respectively. This method does not require time-consuming pre-treatment and is suitable for the routine assay of plasma samples.

Animals↗

PubMed2005

Successful management of discovered pH dependence in vancomycin recovery studies: novel HPLC method for microdialysis and plasma samples.

Vancomycin is a glycopeptide antibiotic approved for the treatment of serious infections or patients allergic to beta-lactams. A rapid HPLC assay using UV detection for the determination in microdialysate and human plasma was developed. After sample preparation, using methanol and trichloroacetic acid for plasma and water for microdialysate, 20 microL were injected and separated on a RP(18) column. Overall, the assay exhibited good precision and accuracy. The diffusion properties of vancomycin investigated in in vitro microdialysis experiments revealed an unfavourable concentration dependence avertable by keeping a constant pH using phosphate buffer as perfusate. The mean relative recoveries were 27.8% [coefficient of variation (CV) 11.1%] and 33.2% (CV 8.3%) for retrodialysis and recovery experiments, respectively. Following characterization of vancomycin in in vitro microdialysis, the developed setting is suitable for application in (pre-)clinical studies.

Chromatography, High Pressure Liquid↗

PubMed1994

Evaluation of the macrocyclic antibiotic vancomycin as a chiral selector for capillary electrophoresis.

Vancomycin is one of a family of related macrocyclic glycopeptide antibiotics that were discovered by scientists at the Eli Lilly Company in the 1950s. It has been used to treat severe staphylococcal infections, particularly when bacterial resistance to other antibiotics has developed. Vancomycin is a naturally occurring chiral compound and has a number of stereogenic centers. Furthermore, it contains a variety of functionalities that are known to be useful for enantioselective interactions (e.g., hydrogen bonding groups, hydrophobic pockets, aromatic groups, amide linkages, etc.). The physiochemical properties of vancomycin, including its stability in solution, are discussed as they pertain to capillary electrophoresis. Over 100 racemates were resolved including many nonsteroidal antiinflammatory drugs, antineoplastic compounds and N-derivatized amino acids. Many of these compounds had very high resolution factors. Optimization and the effect of different experimental parameters on the enantioselective separations are discussed.

Amino Acid Sequence↗

PubMed2003

Salt dependence on vancomycin-herbicide enantiomer binding: capillary electrophoresis study and theoretical approach.

In a previous paper, a mathematical model was developed for the estimation of binding constants by capillary electrophoresis (Guillaume and Peyrin, Anal. Chem. 1999, 71, 2046-2052). This model was applied to determinate the binding constant of the guest-vancomycin complex as well as the degree of complexation n(c) (percent of complexed guest). In this work, the guest molecule were a series of acid herbicide enantiomers (aryloxypropionic, aryloxyphenoxypropionic, and aminopropionic acid). The effects of the run buffer salt concentration on the herbicide-vancomycin binding was clearly described by the determination of specific physicochemical parameters as well as thermodynamic data. These results demonstrate that a better understanding of the interactions involved in the guest molecule-vancomycin binding allows to optimize the enantiomeric separation of this chiral guest molecule.

Electrophoresis, Capillary↗