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PubMed2006

[Surveillance study of vancomycin resistant enterococci in pediatric haematology and oncology patients].

In this study, the prevalence and risk factors of fecal carriage of vancomycin resistant enterococci (VRE) among patients in Ondokuz Mayis University Pediatric Hematology and Oncology Clinics have been investigated. During two months, rectal swab samples were collected weekly from all of the patients hospitalized in Pediatric Hematology and Oncology Clinics, for the surveillance cultures. During the study a total of 85 rectal swabs were obtained from 34 patients who had been hospitalized in the inpatient clinic with 20 bed capacity. The number of samples obtained from the patients varied between 1-6 cultures. All of the patients (100%) had peripheral venous catheters and 27(79%) of patients had used antibiotics. All of the samples were inoculated onto 8 microg/ mL gentamicin containing blood agar media, and enterococci were identified by Gram staining, catalase test and at species level by VITEK 2 (bioMérieux, France) automated system. Vancomycin resistance was screened by using 6 microg/mL vancomycin containing brain-heart infusion agar according to CLSI guidelines. The vancomycin MIC values of the strains grown in this medium were determined by microdilution test proposed by CLSI. As a result, a total of 50 samples (59%) belonging to 24 patients yielded enterococci, and the species distribution was as follows; E. faecium (in 16 cases), E. faecalis (in 8 cases), E. casseliflavus (in 6 cases), E. avium (in 3 cases) and E. durans (in 1 case). In our study no vancomycin resistance nor VRE colonization was detected in the patients.

Adolescent↗
PubMed2006

Emerging vancomycin resistance in enterococci in India.

Infection caused by vancomycin resistant enterococci (VRE) leads to adverse outcome and is a real challenge. Despite increasing reports of VRE in different countries, there is scanty data on this issue from India. A total of 685 enterococci were isolated from various clinical samples from January to December 2004. Antimicrobial susceptibility was performed as prescribed by National Committee for Clinical Laboratory Standards (NCCLS). Vancomycin resistance was confirmed by minimum inhibitory concentration (MIC). Resistant phenotype was determined by Polymerase chain reaction (PCR). Of 685, 456 (67%) were E. faecalis and 229 (33%) were E. faecium. Resistance to various antibiotics in E. faecalis and E. faecium was as follows: ampicillin 33% and 54%, erythromycin 91% and 86%, ciprofloxacin 69% and 81%, tetracycline 50% and 54% and high level gentamicin resistance in 62% and 77% respectively. Vancomycin resistance was confirmed in 10 (1.4%) cases by MIC and all had Van A phenotype by PCR. Emergence of vancomycin resistant enterococci is of great concern because of its epidemic potential and scanty therapeutic options. Prompt diagnosis and efficient infection control measures can restrict its spread.

Anti-Bacterial Agents↗
PubMed1990

[Enterococci as pathogens of severe infections in newborn infants and young infants].

We report about severe perinatal infections caused by enterococci during a 5 year-period. Between January 1983 and December 1987 8 infants were treated in the Department of Neonatology of the Charité-Hospital, 5 of them died. In 4 of the infants this infection was of the early onset type and in 4 infants the infection had a late onset. The clinical course of the four infants with early onset type was very similar to that of infants with group-B-streptococcus disease. The increase of severe infections caused by enterococci in 1987 (7 cases) is unclear. One cause of the increase could be, that the chemotherapy of septicemia and meningitis in the Department of Neonatology of the Charité is the combination cefotiam and gentamicin or cefotaxime and gentamicin. Enterococci are resistant to all cephalosporins and a selection of these pathogens after this therapy is possible. In vitro and clinical experience has demonstrated, that a ampicillin-gentamicin combination constitutes effective therapy for enterococcal infection.

Enterobacteriaceae↗
PubMedDate not supplied

[Production of non-volatile amines by strains of enterococci].

During the last few years there has been great interest concerning the problems related with the presence of pressor amines in different kinds of cheese, specially since the "cheese syndrome" was made evident. Since the capacity of the bacterial groups involved in cheese manufacture to produce these amines has not yet been clarified, it was decided to study the production capacity of tyramine, tryptamine and histamine of enterococci strains probably used in the starter cultures. Forty-one enterococci strains were analysed cultivating them in milk and in milk with the addition of the corresponding aminoacids. It was determined that only low percentages of Streptococcus faecalis subsp. liquefaciens and Streptococcus durans strains (34% and 11% respectively) produced traces of tyramine and tryptamine in milk. But when cultivated in the presence of the corresponding aminoacids, a large percentage of strains of all the species produced tyramine in high concentrations and different percentages of them produced tryptamine in concentrations no higher than 200 ppm. All strains analysed proved to be unable to produce histamine. It can be concluded that there exists a strong probability for enterococci to produce tyramine and tryptamine in different concentrations specially when developed in the presence of the corresponding aminoacids.

Amino Acids↗
PubMed1989

Risk factors for acquisition of gentamicin-resistant enterococci. A multivariate analysis.

High-level gentamicin resistance in enterococci is an increasing problem in hospitalized patients. Multiple risk factors for the acquisition of these organisms have been identified, but these risk factors are highly interrelated, and it has been unclear which of them are truly important. We performed a case-control study comparing 37 patients colonized or infected with resistant enterococci with 84 patients with susceptible strains. Crude odds ratios were significant for nosocomial acquisition, duration of hospitalization, hospitalization on the medical service or in an intensive care unit, number and duration of antibiotics received, and receipt of several individual antibiotics. By logistic regression, hospitalization longer than 2 weeks (odds ratio, 5.4; 95% confidence interval, 1.7 to 17) and receipt of five or more antibiotics (odds ratio, 26; 95% confidence interval, 2.8 to 250) were significantly associated with colonization or infection with resistant enterococci. Patients with these latter two risk factors may be targeted in infection control efforts.

Aged↗
PubMed1986

[In vitro comparative study of piperacillin-aminoglycosides combinations against Enterococci and Enterobacteriaceae].

The hundred and ninety-two combinations were tested against 17 strains chosen from the results of MIC determination (disc method): 5 enterococci exhibiting low level resistance (r) or high level resistance (R) to streptomycin (S) and gentamicin (G): 2 strains Sr Gr, 2 strains SR Gr and 1 strain Sr GR; 12 enterobacteria chosen for their resistance phenotypes to beta-lactams and aminoglycosides and because they are the most frequent clinical isolates: 2 strains Amos Tics Ctns (group 1), 4 strains AmoR Tics CtnR (gr. II), 4 strains AmoR TicR Ctns (gr. III) and 2 strains AmoR TicR CtnR (gr. IV). MIC and MBC were assessed for the 17 strains (Mueller Hinton broth). Combinations were carried out by a checkerboard micromethod. FBC index was calculated for each combination. Against enterococci the 50 combinations were: piperacillin versus ampicillin + aminoglycosides (streptomycin, tobramycin, amikacin, gentamicin, netilmicin). Against enterobacteria piperacillin was combined with different aminoglycosides depending on their resistance phenotypes. These combinations were compared with ticarcillin or mezlocillin or cefotaxime + aminoglycosides (total number 142). The species studied produced different results: with the enterococci Gr synergistic effects (FBC = 0.62-0.75) were rare; additive and indifferent effects were predominant. With the GR strain some antagonistic effects were observed. With the enterobacteria, in groups I and II synergistic effects were frequent and almost equivalent regardless of the beta-lactam chosen. In groups III and IV (TicR) piperacillin MICs were greater than or equal to 128 mg/l and mezlocillin MICs greater than 512 mg/l; the synergistic effects were significant (FBC from 0.25 to 0.62). beta-lactam + amikacin or netilmicin, and especially piperacillin + amikacin, were found to have the most frequent synergistic effects upon the strains tested. Mezlocillin combinations cannot be used clinically; the use of piperacillin combinations requires further discussion. On the other hand, cefotaxime + aminoglycosides combinations are active against those TicR strains.

Aminoglycosides↗
PubMed1988

[A modified medium, bile esculin-pyrrolidonyl-beta-naphthylamide, for rapid differentiation between enterococci and nonenterococci].

A new medium was developed by adding 40 mg pyrrolidonyl-beta-naphthylamide (PYR) to 1 l bile esculin (BE) agar, and was named as BE-PYR agar. To evaluate the efficacy of BE-PYR agar in differentiating enterococci from nonenterococci, we inoculated 207 strains of group D streptococci (including 157 enterococci and 50 nonenterococci) to BE-PYR agar. After incubating overnight at 35 degrees C incubator, following by applying the PYR reagent to test the color change of colonies, results indicate that the accuracy of BE-PYR agar in the differentiation of enterococci from nonenterococci reaches to 100%. Therefore, BE-PYR agar was considered to be an effective laboratory tool in further differentiation of group D streptococci.

Agar↗
PubMed1987

Enterococci and aminoglycosides: evaluation of susceptibility and synergism of their combination with piperacillin.

Some clinical isolates of enterococci were tested for susceptibility to gentamicin, tobramycin, amikacin and netilmicin. Five percent of Streptococcus faecalis tested demonstrated high level resistance (minimum inhibitory concentration (MIC) greater than 2024 micrograms/ml) to gentamicin, tobramycin and netilmicin, while amikacin had MICs greater than 128 micrograms/ml for all strains tested. Since a combination of a beta-lactam and streptomycin does not produce synergism against all strains of enterococci for an increase in the number of highly resistant strains, the effect of piperacillin plus gentamicin, tobramycin, and netilmicin was examined. The combination piperacillin + netilmicin seemed to be very effective against all enterococci tested.

Aminoglycosides↗
PubMed1988

Trimethoprim resistance in enterococci: microbiological and biochemical aspects.

Synergy was found between sulphonamide and trimethoprim in ratios 1:1 and 20:1 against both trimethoprim-sensitive enterococci (17 strains) and trimethoprim-resistant enterococci (23 strains). Many of these strains were resistant to kanamycin, tetracycline, streptomycin and/or erythromycin. Resistance to kanamycin, but not to trimethoprim, was clearly associated with the presence of a plasmid of molecular weight 35-45 Md. Elimination of this plasmid in three out of four highly trimethoprim resistant strains brought about loss of resistance to both kanamycin and trimethoprim. Furthermore, it was possible to transfer trimethoprim resistance from three of five highly resistant strains, but not from three strains with low-grade resistance. It is concluded that resistance to trimethoprim in enterococci can be encoded on a plasmid, and that the gene responsible may be on a transposon. No significant differences were found between the specific activities of dihydrofolate reductase from trimethoprim-sensitive and -resistant strains. The enzyme from resistant strains was several orders of magnitude less susceptible to inhibition by trimethoprim than was the enzyme from sensitive strains.

Conjugation, Genetic↗
PubMed1978

[Differential diagnosis of enterococci].

The most stable differential signs of enterococci are: growth in the medium at pH 10.2, growth in broth containing 40% bile, citrate utilization, resistance to 0,05% potassium tellurite, 2, 3, 5-triphenyltetrazolium chloride (TTC) reduction, the staining of colonies (plaques) on a medium with manganese, iron and zinc salts, glycerine fermentation under anaerobic conditions, mannite fermentation, the presence of hemolysin, of the proteolytic enzyme, and mobility. Combined differential-diagnostic nutrient medium permits to determine simultaneously 5 enterococci signs--resistance to nalidixic acid and to crystal violet, TTC reduction, hemolytic and proteolytic activity. The suggested scheme of enterococci laboratory diagnosis including a set of hard nutrient media poured into multisection Petri dish is simple reliable and accessible for any bacteriological laboratory.

Culture Media↗
PubMed1987

[Importance of Streptococci and in particular of the Enterococci in urinary tract infections].

Out of 1336 bacterial strains isolated by urine cultures, nearly 23% resulted to be Gram-positives of which 11.8% are Enterococci and 3% Streptococci of Group B. The isolated Enterococci resulted to be sensitive mostly to amoxicillin and resistant to cephalosporins and tetracycline. The authors consequently agree with recent recordings of an accentuated incidence of Enterococci on infections of the urinary tract.

Female↗
PubMed1983

Sensitivity of enterococci to beta-lactam antibiotics, co-trimoxazole, nitrofurantoin, tetracycline and doxycycline.

The current sensitivity of enterococci to a total of 20 antibiotics (5 penicillins, 11 cephalosporins, cotrimoxazole (trimethoprim + sulfamethoxazole), nitrofurantoin, tetracycline, and doxycycline) was evaluated by determining the respective MICs. Ampicillin is certainly the drug of first choice for the treatment of moderately severe infections due to enterococci. Nitrofurantoin is equally effective in urinary tract infections. Co-trimoxazole is a suitable alternative in the presence of penicillin allergy. Penicillin G and tetracyclines should not be used in enterococcal infections. All cephalosporins presently available are ineffective against these bacteria. In view of the results of in vitro sensitivity test for bacteria, acylureido penicillins should be preferred to cephalosporins in very serious infections and mixed infections, especially in immunocompromised hosts. Azlocillin, mezlocillin and piperacillin are the most effective drugs to prevent superinfections with enterococci in clinically and bacteriologically defined situations. The combination of these drugs with aminoglycosides is the most effective antibiotic therapy for serious infections known so far. The influence of inoculum density on MIC and MBC values was investigated. The detailed discussion of the laboratory's own results and of the data reported in the literature points to the inadequacies of the test methods which have been used so far.

Anti-Bacterial Agents↗
PubMed1980

[Reducing activity and differential thermal analysis of enterococci].

The reducing activity of 100 Streptococcus faecalis strains, 100 Streptococcus faecium strains and 100 enterococcal strains were studied by the quantitative method. The study revealed that all mobile enterococci, in contrast to S. faecium, reduce 2,3,5-triphenyltetrazolium chloride with the formation of triphenylformasan. Differential thermal analysis also indicated that S. faecalis, S. faecium and mobile enterococci had thermograms with definite mathematical characteristics and could be best differentiated by the indices of their form and the size of S3 areas. The quantitative methods of the investigation of reducing activity and differential thermal analysis can be used for the differentiation of enterococcal species. Mobile enterococci have definite characteristics allowing one to sharply differentiate them from S. faecium and S. faecalis.

Animals↗
PubMed1981

[Immunological reactivity to the products of normal microflora. III. Characteristics of antibodies to the common antigens of enterobacteria, enterococci and bifidobacteria].

The content and type of antibodies to the common antigens of enterobacteria, enterococci and bifidobacteria were studied in serum specimens obtained from 220 donors. Antibody titers to enterobacteria were almost twice as high as those to enterococci and 8 times higher than those in bifidobacteria. The final titer of the reaction with enterobacterial antigens in 90% of the donors was determined by IgG (7S); in respect of enterococci and bifidobacteria IgM played the leading role in 56% and 74% of the cases, respectively. In most cases the profile of immune responsiveness was characterized by marked individuality and comprised various titers and types of antibodies to the antigens of all three groups of bacteria. The results thus obtained are analyzed from the viewpoint of normal responsiveness to standard immunological stimuli; all individuals come in contact with such stimuli with an equal degree of probability.

Antibodies, Bacterial↗
PubMed1981

[Results from the Central Laboratory for Streptococci Research in Kiel from 1965 to 1980 - group D-streptococci (enterococci) (author's transl)].

In accordance with previous papers published within a series of publications which describe the results obtained from the Central Laboratory for Streptococcal Research in Kiel (1. Survey, 2. Mastitis-Streptococci) the group of Enterococci is discussed herewith. On the basis of more than 6000 strains which are stored in our databank including all biological characteristics, the distribution of the cultural, biochemical and serological parameters is listed in percentages, and the usefulness and reliability for the identification of the enterococcal group and also the differentiation of particular species is discussed. The results are tabulated for every single species and additionally, for serologic-positive and negative strains. For example, it can be shown that a third of all Str. faecium strains are motile, that lack of growth at 45 degrees C varies between 1.1% and 31.3% and that lack of serological reaction with group D-serum between 0.9% and 70%. In a comprehensive table and flow diagram these figures result in a proposal for a simple but sufficient identification procedure on different stages (enterococci, faecalis- or faecium-group, single species) depending on the individual requirements. With regard to the incidence of enterococci in man and animals, which was presented in the first paper, the organ sources of the different species are compared now. Apart from some interesting findings it can be stated that a typical predominance of the faecalis and faecium-group resp. in man or animals cannot be confirmed. But there seems to be a relation between the species and the organ source. For example, in humans the faecium-group predominates in the respiratory tract, but in the urogenital tract the presence of Str. faecalis is seven times higher than the faecium-group. The above results may also be of interest for ecological reasons and may be important for the pathogenesis and epidemiology of this streptococcal group.

Animals↗
PubMed1995

Enterococci: susceptibility patterns and therapeutic options.

Enterococci do not possess the common virulence factors found in many other bacteria, but they have a number of other characteristics which make them particularly pathogenic. These organisms are intrinsically resistant to a number of antimicrobial agents, including beta-lactams (penicillins and cephalosporins), polymyxins and the lincosamides. They are also tolerant to the bactericidal activity of penicillins and glycopeptides, and some of the group have acquired resistance to a number of other clinically important antimicrobial agents including ampicillin, aminoglycosides, chloramphenicol and erythromycin. Numerous national and international studies have demonstrated the changes in the antibiotic resistance of enterococci. Many strains now exhibit multiple drug resistance, the most important being high-level resistance to streptomycin and gentamicin. Organisms exhibiting this high-level resistance are usually resistant to all synergistic combinations of beta-lactam antibiotics and aminoglycosides. Ampicillin-resistant strains are now emerging, some of which are beta-lactamase producers. While resistance to glycopeptides remains rare, it is increasing dramatically in many areas of the world. As nosocomial isolates of enterococci have displayed resistance to essentially every useful antimicrobial agent, it is likely to become increasingly difficult to treat and control enterococcal infections. The glycopeptide antibiotics vancomycin and, particularly, teicoplanin are the only alternatives currently available. Although a bactericidal combination of antibiotics appears necessary only in endocarditis and meningitis and although knowledge of the prevalence of resistant strains can be used to guide the selection of appropriate therapy, optimal regimens for the treatment of infections caused by multiresistant strains have yet to be determined.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Resistance, Microbial↗
PubMed1995

Multidrug-resistant enterococci: a threat to the surgical patient.

The enterococcus has become an important nosocomial pathogen, reported by the National Nosocomial Infections Surveillance System as the third most common pathogen associated with blood-stream infections and the second most commonly isolated pathogen overall. It is now more frequently recognized as a cause of superinfection in the surgical patient, as the possible result of the frequent use of ineffective antimicrobials for prophylaxis and treatment. Both of these findings are due, in part, to the intrinsic antimicrobial resistance of the enterococci. Of greater concern is the ready ability of this organism to acquire resistance traits. During the past 5 years, the appearance and rapid dissemination of strains with high-level resistance to vancomycin, ampicillin, gentamicin, and streptomycin have been reported; in some cases, no effective antimicrobial therapy was available to patients infected with these strains. Enterococci, in addition to their intrinsic and acquired tolerance to beta-lactams, have acquired the ability to inactivate penicillin and ampicillin via beta-lactamase production. Prompt recognition of such multiresistant enterococci, the implementation of effective infection control precautions, and rational use of antimicrobials may limit or even prevent the spread of such strains in the hospital setting.

Anti-Bacterial Agents↗
PubMed1993

Antimicrobial susceptibility of enterococci in vitro.

Treating patients with enterococcal infections has become difficult because of the emergence of several resistant traits in the past decade, including high-level resistance to gentamicin, beta-lactamase production, non-beta-lactamase-associated penicillin resistance and vancomycin resistance. To determine the antimicrobial susceptibility and to survey the antibiotic resistance of enterococci, we tested 111 clinical isolates of enterococci from the National Taiwan University Hospital from 1990 to 1991. There were 102 isolates of Enterococcus faecalis, five of Enterococcus faecium, and four of other enterococcal species. All these isolates were tested in vitro by the agar dilution method for determination of the minimal inhibitory concentration (MIC), by the broth microdilution test for screening of high-level resistance to gentamicin and by the rapid chromogenic cephalosporin method for detection of beta-lactamase production. The effect of the combination of two antimicrobial agents against 20 of the 111 isolates, including strains with high-level and low-level resistance to gentamicin, were further checked by the checkerboard titration method. Among 17 antimicrobial agents, the most active agent was ampicillin, followed by vancomycin, ciprofloxacin, ofloxacin and penicillin. Although none included in these were beta-lactamase producers or vancomycin-resistant strains, there was a high proportion (62%) with high-level resistance to gentamicin among our isolates. There were 11 isolates, seven Enterococcus faecalis and four Enterococcus faecium, which had MICs beyond the clinically achievable level of penicillin (MIC > or = 64 micrograms/mL). Because these resistant isolates of enterococci have important therapeutic implications, periodic surveillance and MIC testing are suggested.

Anti-Bacterial Agents↗