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The author worked out a method of enterocinotyping on enterococci. A possibility of enterococcus typing by means of a set of enterocinogenic enterococcus strains was shown. A mobile enterococcus 4 (10 p) strain, possessing a high antagonistic activity, is suggested for enterococcus identification. Differentiation of enterococcus species by the enterocine sensitivity proved to be impossible.
The genus Enterococcus consists of at least 12 species, two of which account for over 95% of the clinically important strains, E faecalis (85%-90%) and E faecium (5%-10%). Despite their ubiquity and frequent isolation, they have not been thought to cause serious disease because they lack common virulence factors. Now, however, enterococci are regarded as true pathogens and are the second leading cause of nosocomial infections. This change results from their increasing antimicrobial resistance and the extensive use of antimicrobial drugs (for example-cephalosporins) that are not active against them. Serious infections should usually be treated with a beta-lactam and an aminoglycoside, but glycopeptides have been increasingly used during the last decade. Two novel resistance patterns of particular concern recently are high level aminoglycoside resistance (HLAR) and vancomycin resistance. The prevalence of HLAR is between 15% and 55%, and glycopeptide resistance has become widespread in various geographical areas. This poses a serious problem, as such resistance may spread to other Gram-positive organisms and is often associated with resistance to other antimicrobial drugs. This may theoretically result in groups of organisms for which there will be no effective antimicrobial treatment.
A total of 670 washings from various household articles were studied in creches and kindergartens for fecal contamination with the aid of two bacteriological tests (coli and enterococal titres); the degree of their contamination with enterococci and E. coli differed. Strongly contaminated objects (diapers, swaddling tables) were revealed with equal frequency by both tests, but objects assessed as moderately contaminated were more frequently revealed by the enterococcus test (P less than 0.05) than by colimetry. Criteria of evaluation of the quality of washings by the data of enterococcometry are suggested.
Studied were a total of 270 samples of raw and pasteurized milk taken during the various technologic states of pasteurized mild produced for consumption at the State Economic Enterprise "Serdica", establishing the enterococcus and coli titers. It was found that the enterococcus titer of the raw milk varies from 10(-3) up to 10(-6), and the titer of the pasteurized milk at the enterprise and upon delivery through its commercial channels is from 1 up to 10(-3). The enterococcus titer of milk that was pasteurized and was kept for 24 hours at 4-5 degrees C was found to range from 1 to 10(-3), and of milk kept at 18-22 degrees C --from (0(-1) to 10(-6). Full coincidence of the enterococcus titer with the values of the coli titer was found only for pasteurized milk kept under refrigerator conditions. Along with the coli titer the enterococcus one may be used as a subsidiary means in a more strict bacteriologic control, however, it may not be referred to as the only criterion replacing the coli values in the hygiene evaluation of milk. All species of enterococci in varying counts are established in both raw and pasteurized milk. Prevailing are the strains of the Str. faecium group -- 43.2 per cent, and those of the Str. faecalis group -- 24.6 per cent.
The growth requirements of biochemically defined strains of the enterococcus species Streptococcus faecium, S. faecalis, S. faecalis var. zymogenes and S. faecalis var. liquefaciens were compared. Arginine, glutamic acid, histidine, leucine, methionine and valine were essential and isoleucine, tryptophan, adenine and uracil were stimulatory to growth for all testes strains. Variation in the specific requirements occur for alanine, glycine, and serine representing strains differences. Threonine was essential for S. faecium strains but had no effect on the growth of strains of other species of enterococci.
This work presents enterococci and staphylococci isolated from the rumen content of fallow deers, their characteristics and antimicrobial activity. On the basis of biochemical tests, strains isolated were allotted to the species Enterococcus solitarius, E. malodoratus, Staphylococcus warneri, S. aureus, S. sciuri subsp. sciuri and S. xylosus. All strains produce lactic acid in the range from 0.303 to 0.500 mol.l-1. Isolated strains were found to be resistant or sensitive to the antimicrobial additives screened. Most isolates showed antimicrobial activity against both Gram-positive and Gram-negative test organisms reaching clear zones of inhibition (diam. 2-5 mm) with bacteriocidic effect.
As part of continual surveillance for antibiotic resistance among pathogens associated with nosocomial infections, a recent analysis of data reported to CDC's National Nosocomial Infections Surveillance (NNIS) system demonstrated a 20-fold increase in the percentage of enterococci associated with nosocomial infections that are resistant to vancomycin from January 1, 1989, through March 31, 1993. Many of these strains are resistant to all available antimicrobial agents. This report summarizes that analysis.
The bi-functional enzyme 6'-aminoglycoside acetyltransferase (AAC-6')-2" aminoglycoside phosphotransferase (APH-2"), which is encoded by the 2 kb fused gene aacA-aphD, mediates gentamicin resistance in Enterococcus faecalis. This gene is associated with the composite transposon Tn5281 that shares extensive homology with transposons Tn4001 and Tn4031 found in staphylococci. Typically these transposons are characterized by the resistance gene being flanked by 1.35 kb insertion sequences (IS256). The resistance gene (aacA-aphD) appears identical among all E. faecalis studied, but restriction enzyme analysis indicates notable heterogeneity within the flanking regions. Various combinations of IS256-like and IS257-like elements, or portions thereof, have been described in different resistant isolates. As gentamicin resistance has been described in other enterococcal species (E. faecium, E. avium, E. gallinarum, E. raffinosus, E. casseliflavus) homology with the resistance gene of E. faecalis has largely been maintained, but more extensive variations in the flanking sequences have been noted. Although many similarities exist among enterococcal gentamicin resistance determinants, heterogeneity in the flanking regions indicates that measurable divergence exists among these determinants. This divergence may be of value in characterizing the mechanisms and natural course of gentamicin resistance dissemination which now includes staphylococci, enterococci and streptococci.
Strains of vancomycin-resistant enterococci (VRE) have emerged and spread widely throughout the United States during the last few years. Multiply-resistant strains of Enterococcus faecium are especially troublesome because they are often resistant to all commercially available antimicrobial agents. At present, VRE infections occur most often in hospitalized patients with severe underlying disease who have undergone invasive procedures and received prolonged courses of broad-spectrum antimicrobial therapy. Because therapeutic options are limited, prevention of spread from patients with known cases to other vulnerable patients is essential.
Vancomycin-resistant enterococci (VRE) are a major problem in numerous institutions in the United States. Most VRE are resistant to all available antimicrobial agents, resulting in serious therapeutic dilemmas. The resistance genes are transmitted on transposons, so the potential for dissemination to other species is significant. Risk factors associated with VRE infection and colonization are vancomycin and cephalosporin use, but numerous patient-related factors also contribute. Although resistant strains appear to arise from the patient's endogenous flora, VRE may be spread through direct contact with contaminated environmental surfaces and hands of caregivers. Published guidelines for preventing such spread suggest implementing infection-control practices and vancomycin restrictions. The ideal drug regimen for the treatment of VRE is unknown. Various drug combinations have been studied in the laboratory, but patient treatment data are scarce. There is an urgent need for new antimicrobial agents.
In this work we have evaluated the in vitro activity of teicoplanin and cefpirome to Enterococcus sp. combined with aminoglycosides gentamicin, tobramycin, netilmicin and amikacin. The combination with a greater percentage of synergy were teicoplanin plus tobramycin (70%), continued by teicoplanin plus gentamicin (69%) and teicoplanin plus netilmicin (58%). The combination of teicoplanin plus aminoglycosides results of great utility in the treatment os serious infections such as endocarditis, meningitis and bacteremia by enterococci, in allergic cases, or resistance to penicillin.
OBJECTIVE: To document the incidence of high-level gentamicin resistance (HLGR) in enterococcal isolates at Johannesburg Hospital. DESIGN: Survey of laboratory isolates. SETTING: Academic hospitals. BACTERIAL STRAINS: Consecutive samples of enterococcal isolates. MAIN OUTCOME MEASURE: The incidence of HLGR in enterococcal isolates. RESULTS: The incidence of HLGR was 26.5% of Enterococcus faecalis isolates and 20% of E. faecium isolates grown during the study period. CONCLUSIONS: High-level gentamicin resistance is common among enterococci isolated at Johannesburg Hospital, and this observation must be considered in defining strategies for the management of invasive enterococcal infections in the future.
Since 1995 patients with infections with vancomycin-resistant enterococci (VRE) have been reported in Rotterdam, the Netherlands. From prevalence studies in the Netherlands at the end of 1995 and the start of 1996, it appeared that 2% of the patients studied in and outside hospitals had VRE. Restrictive antibiotic prescription in human and veterinary medicine is indicated in order to postpone the problem.
The emergence and dissemination of vancomycin-resistant enterococci (VRE) emphasizes the need for laboratories to be able to correctly detect them. The study described was conducted to evaluate the test methods presently available in Japan to discriminate between the isolates of VRE and those susceptible (VSE). Among the phenotypic test methods evaluated, an agar screening method which utilized 8 micrograms per ml of vancomycin in Mueller-Hinton agar plate appeared to have a sufficient accuracy. When 23 isolates of vanA positive, 31 of vanB positive, 4 of both positive and 60 of both negative were tested, the sensitivity and specificity to detect VRE were estimated to be 98.3% and 100%, respectively. Also, all the VRE isolates were interpreted as being resistant or intermediate by the E test recently approved in Japan, when the results were read after 48 hr-incubation. Whereas, two disk diffusion tests, Showa disk and NCCLS-based Sensi-disc, were evaluated, but both methods failed to discriminate between VRE and VSE, in particular, between the isolates with vanB positive and negative. The automated system, Vitek GPS-TA produced high frequencies of very major errors; 8.7% for vanA positives and 58% for vanB positives. A total of 1,214 enterococcal isolates from multisite laboratories in Japan, comprising 7 different species, were first tested onto agar screening test plates, but none of isolates represented phenotypic vancomycin resistance. With these results, it can be recommended to detect VRE in clinical microbiology laboratories as follows: First, all the enterococcal isolates will be tested onto the agar screening plates or by the E test. Then, if the isolate is interpreted as being resistant or intermediate, the laboratory should confirm whether it is positive for vanA or vanB by polymerase chain reaction (PCR) specified.
BACKGROUND: The aim of this study was to evaluate the antimicrobial resistance of enterococci isolated from blood samples in three hospitals in Madrid (Spain) from 1994 to 1995. METHODS: One hundred strains, 83 Enterococcus faecalis, 15 E. faecium, and 2 E. durans, isolated from January 1994 to April 1995 were studied. The minimum inhibitory concentrations (MIC) of 11 antimicrobians were determined by the agar dilution method. RESULTS: Four percent of the strains were resistant to ampicillin and 7% to penicillin. Ninety-two percent were sensitive to vancomycin. The percentage of strains with a high level of resistance (HLR) to some aminoglucoside was 60%. HLR was observed to gentamycin in 41%, to streptomycin in 46% and to kanamycin in 58% of the strains. Half of the isolates were resistant to the fluoroquinolones tested. HLR was significantly associated with aminoglucosides with HLR (MIC > or = 16 mg/l) to fluoroquinolones in the strains studied (p < 0.001). CONCLUSIONS: The incidence of resistance to ampicillin and vancomycin is low and very high to aminoglucosides and fluoroquinolones. There is also a very significant association between HLR to fluoroquinolones and HLR to aminoglucosides.
Drug resistance in enterococci isolated from hospitalized patients is reported. Out of 421 strains tested, 45 (10.7%) showed high level aminoglycoside resistance (HLAR). At the species level, 8.2 per cent of Enterococcus faecalis and 33.3 per cent of E. faecium were HLAR. While all the strains of E. faecalis were sensitive to vancomycin, one strain of E. faecium was vancomycin resistant.
The incidence of vancomycin-resistant enterococci (VRE) infection is increasing. Immunosuppressed individuals are particularly vulnerable to infection with VRE. Strict attention to infection control measures is important in preventing the spread of multiresistant organisms.
In vitro synergy between penicillin and pefloxacin against Enterococcus hirae and Enterococcus faecium strains with different penicillin susceptibility was studied. The combination was synergistic against penicillin-resistant strains. E. hirae R40 and E. faecium 28R, but not against the penicillin-susceptible ones (E. hirae ATCC 9790 and E. faecium 28S). Analysis of PBPs of cells, grown in the presence of pefloxacin, showed that PBP5 of penicillin-resistant strains, the PBP responsible for the resistance of enterococci to beta-lactam antibiotics, is consistently reduced while it is almost unaffected in the penicillin-susceptible strains even at the highest concentrations of pefloxacin. These results indicate that pefloxacin interferes with the mechanism of synthesis of PBPs and particularly of PBP5, a protein whose production has already been modified in resistant strains, in some way rectifying the previous alteration.