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PubMed1998

Use of tests for acidification of methyl-alpha-D-glucopyranoside and susceptibility to efrotomycin for differentiation of strains of Enterococcus and some related genera.

A total of 107 Enterococcus strains, 10 Vagococcus fluvialis strains, and 8 Lactococcus garvieae strains were tested for acidification of methyl-alpha-D-glucopyranoside (MGP) and susceptibility to 100-microg efrotomycin (EFRO) disks. All 26 strains of Enterococcus casseliflavus, including 3 nonmotile and 2 nonpigmented strains, acidified MGP and were resistant to EFRO. All 22 strains of Enterococcus gallinarum, including 5 nonmotile strains, also acidified MGP and were resistant to EFRO. None of the 26 strains of Enterococcus faecium acidified MGP, and all were susceptible to EFRO. Although all 12 Enterococcus faecalis strains were also negative in the MGP test, they were resistant to EFRO. Other enterococcal strains gave variable results. All 10 strains of V. fluvialis and all 8 strains of L. garvieae gave positive and negative results, respectively, in the MGP test and were, respectively, resistant and susceptible to EFRO. These results indicate that tests of the production of acid from MGP and susceptibility to EFRO can be used as adjunct tests in the identification of typical and atypical strains of enterococci in the clinical microbiology laboratory.

Anti-Bacterial Agents↗
PubMed1997

Subdural empyema due to Enterococcus faecalis.

Central nervous system infections due to Enterococcus species are uncommon. We report the first case of subdural empyema due to Enterococcus faecalis. Following partial treatment of a middle ear infection due to Enterococcus species and mixed coliforms, the patient developed signs of meningeal involvement. A lumbar puncture showed a raised polymorph cell count, but was sterile on culture; broad-spectrum antimicrobial therapy with cefotaxime, flucloxacillin and metronidazole was commenced. Following development of focal neurological signs, a CT scan revealed a subdural collection. Drainage and culture of the pus yielded a pure growth of Enterococcus faecalis. This case demonstrates the need to remain aware of the ability of the Enterococcus to cause serious infections and to direct specific antimicrobial therapy accordingly.

Adolescent↗
PubMed1998

Isolation and characterization of an Enterococcus-like bacterium causing muscle necrosis and mortality in Macrobrachium rosenbergii in Taiwan.

A Gram-positive, ovoid, diplococoid bacterium tentatively identified as Enterococcus-like was isolated from diseased Macrobrachium rosenbergii in Taiwanese aquaculture ponds. The diseased prawns displayed poor growth, anorexia, inactivity, opaque and whitish musculature, and mortality. In histological preparations, melanized hemocytic granulomas were seen in the connective tissue around hemal sinuses together with hemocytic aggregation in necrotic musculature. Five isolates of diplococci were collected from diseased prawns at 4 farms and these were evaluated for 93 characteristics including morphology, physiology, biochemistry and sensitivity to antibiotics. The results indicated that the isolates belonged to a single species. They grew in 0.5 to 6.0% NaCl, at 10 to 40 degrees C, at pH 9.6 and on bile esculin medium, gave positive pyrrolidonylarylamidase, arginine dehydrolase and Voges-Proskauer tests, were resistant to bacitracin and SXT, and were CAMP-negative and non-hemolytic on sheep blood agar. These findings indicated an Enterococcus-like bacterium closely related to Enterococcus seriolicida (recently reduced to synonymy with Lactococcus garvieae). Experimental injection of 3 x 10(5) cells of strain KM002 of this Enterococcus-like bacterium into the ventral sinus of the prawn cephalothorax caused 100% mortality in 11 d, and induced muscular necrosis and hepatopancreatitis, gross signs and histopathology similar to those observed in the naturally infected prawns. It was concluded that this Enterococcus-like bacterium was the etiological agent associated with mortality of the farmed, diseased prawns.

Animals↗
PubMed2000

[Pathogenicity of Enterococcus spp. Characteristics of 169 hospital isolates].

BACKGROUND: To know the characteristics of Enterococcus spp. strains isolated in the hospital; to analyse the importance of this microorganism and its resistance to antimicrobial agents. PATIENTS AND METHODS: Retrospective analysis of the case histories of 169 patients with Enterococcus spp. isolates, selected at random at the Infanta Cristina Hospital in Badajoz. Investigation was carried out on: age, date of admission and discharge, clinical symptoms, risk factors, previous antibiotic treatment, clinical and microbiological evolution, recommended treatment and prescribed treatment. Identification of microorganisms and antibiogram with Pos Combo 41 microScam panels, read on Baxter WalkAway-40 equipment. RESULTS: The most frequently found species was Enterococcus faecalis. In 75 cases the isolations were polymicrobial. The enterococci were isolated mainly from urinary infections (27%), skin infections (20%), intrabdominal infections (14%) and infections from surgical wounds (14%). The existence of peripheral catheter was the main risk factor. All the strains of E. faecalis were susceptible to the glycopeptides. Two strains of Enterococcus faecium were not susceptible to vancomycin and one of these was not susceptible to teicoplanin. Mortality was from 21-27.5%. CONCLUSIONS: Enterococcus spp. is frequently isolated in nosocomial infections, although in approximately half the cases it is associated with other bacteria. For this reason, it is not always possible to determine its pathogenic contribution. The isolated strains, except two strains of E. faecium, are susceptible to vancomycin. A relation exists between high resistance to aminoglucosides and resistance to fluoroquinolones.

Enterococcus↗
PubMed1992

Diarrhea caused by a slow-growing Enterococcus-like agent in neonatal rats.

An enteropathogenic Enterococcus-like agent was isolated from a spontaneous outbreak of diarrhea that occurred in a colony containing neonatal rats. Diarrhea was experimentally reproduced in virus-antibody-free neonatal rats inoculated with this purified "enterococcus." Gram-positive cocci were adhered to the small intestinal villi of affected animals from which the organism was reisolated. The isolate's classification in the genus Enterococcus was confirmed by genetic probe; however, because of its unique fermentation pattern, it could not be definitively speciated. Indirect immunofluorescence assays indicate that this strain of enterococcus and Enterococcus hirae, another strain pathogenic for neonatal rats, differ antigenically. Enterococci should be considered as potential etiologic agents in outbreaks of diarrhea involving neonatal rats and future efforts directed to increasing our understanding of the pathophysiology of this disease.

Animals↗
PubMed1993

Single-dose ampicillin prophylaxis does not eradicate enterococcus from the lower genital tract.

OBJECTIVES: To determine the carriage rate of enterococcus in the lower genital tract of women having a cesarean delivery and to determine whether a single 2-g intraoperative dose of ampicillin eradicates enterococcus from the lower genital tract. METHODS: Lower genital tract cultures were taken in 84 women who were in labor or had ruptured membranes and who were about to have an indicated cesarean delivery. The subjects were randomized to receive either a single 2-g dose of ampicillin or a cephalosporin as prophylaxis. Cultures were repeated 24 hours postpartum. RESULTS: Enterococcus was isolated preoperatively in 33 subjects (39.3%) and postoperatively in 36 (42.9%). The enterococcus was eradicated in five of 17 women (29.5%) who received ampicillin. CONCLUSION: These results suggest that a single 2-g dose of ampicillin does not eradicate enterococcus from the lower genital tract.

Adult↗
PubMed1997

[Isolation rate of Enterococcus spp. from surgical infections and their susceptibilities].

Enterococcus spp. isolated from surgical infections during the period from July 1982 to June 1995 were investigated in a multicenter study involving 19 hospitals in Japan, and the following results were obtained. 1. Though the isolation rate of Enterococcus faecalis and other Enterococcus spp. were not high from primary infections, and from postoperative infections the isolation rate of other Enterococcus spp. was also low, the isolation rate of E. faecalis was highest from postoperative infections after 1993. 2. Vancomycin (VCM) showed strongest activity against E. faecalis, and followed by those of ampicillin (ABPC), imipenem. levofloxacin (LVFX) and meropenem in this order. Against other Enterococcus spp., VCM showed strongest activity, and followed by those of ABPC and LVFX. There were no resistant strains against VCM.

Ampicillin↗
PubMed1998

Effect of quinupristin/dalfopristin alone or in combination with vancomycin on the structure of Enterococcus faecium.

Twenty strains of Enterococcus faecium susceptible to quinupristin/dalfopristin (< 2 mg/l) were DNA fingerprinted to exclude strain duplication. Ten strains were susceptible to vancomycin (minimal inhibitory concentration [MIC] < 2 mg/l) and 10 were resistant to vancomycin (MIC > 400 mg/l). Vancomycin at 1/2 MIC, quinupristin/dalfopristin at 1/4 MIC and their combination, except for a tube control, was added to 10 ml trypticase soy broth tubes which were planted with the respective 24-h trypticase soy broth cultures. The products of incubation were sampled periodically throughout 24 h for gram stain and electron microscopy. Cell size was measured on photographs at 20,000x final magnification and results were statistically analyzed. The cells of all strains of Enterococcus faecium exposed for 12 h to quinupristin/dalfopristin were comparable in size to the control, Most cells, however, showed areas of low density of ribosome in the center of the cells. The cells of Enterococcus faecium resistant to vancomycin exposed to vancomycin were larger than the controls with means of 1.96 micron -2.07 micron versus 1.16 micron (p < 0.001); these cells consisted of individual organisms connected by wide cross walls of abnormal fibrous structure. Enterococcus faecium sensitive to vancomycin exposed to vancomycin remained comparable to the control. The combination of quinupristin/dalfopristin plus vancomycin produced large cells with multiple abnormal cross walls in both vancomycin-resistant and vancomycin-sensitive Enterococcus faecium. The addition of quinupristin/dalfopristin to vancomycin appears to modify the vancomycin-susceptible strains to respond to vancomycin in the same manner as do the vancomycin-resistant organisms.

Anti-Bacterial Agents↗
PubMed1989

Identification of Enterococcus species isolated from human infections by a conventional test scheme.

Streptococci (206 cultures) previously identified as enterococci were retrieved from storage and reidentified by using tests designed to identify species of the genus Enterococcus. Of these 188, 91% were correctly identified as Enterococcus species. Of the remaining strains, nine (4%) were unidentified and six (3%) and 3 (1.5%) were identified as Leuconostoc sp. and Lactococcus sp., respectively. Two new Enterococcus species were discovered: E. raffinosus and E. solitarius. DNA-DNA hybridizations were performed on selected strains to assure correct identification. Cultures representing 10 of the 12 Enterococcus species were among the 188 strains identified. An identification system based on the grouping of key reactions of 20 phenotypic characteristics of Enterococcus species is described.

Bacteriological Techniques↗
PubMed1997

Enterococcus faecium in hospitals.

Most of the characteristics that have ensured the success of enterococci as nosocomial pathogens were described early in this century. Enterococcus faecium and Enterococcus faecalis, the enterococci most frequently isolated from clinical material, differ fundamentally. The intrinsic antimicrobial resistance of Enterococcus faecium, supplemented by acquired resistance mechanisms, can generate a glycopeptide-multiply-resistant nosocomial pathogen that survives on hands and in the environment, and has the potential for intra-hospital and inter-hospital spread. The use of terms such as 'an enterococcus', 'faecal streptococci' and 'group D streptococci' have hindered, and still hinder, our understanding of a species rapidly emerging as the most problematic of nosocomial pathogens.

Anti-Bacterial Agents↗
PubMed1998

Time-kill profiles of Enterococcus to antibiotics used for intravitreal therapy.

BACKGROUND AND OBJECTIVE: To determine and then compare the time-kill profiles of Enterococcus to antibiotics used for intravitreal therapy. PATIENTS AND METHODS: The time-kill profiles of four endophthalmitis isolates of Enterococcus faecalis, one vancomycin-resistant E. faecalis isolate, and three vancomycin-resistant isolates of E. faecium were determined against vancomycin, amikacin, cefazolin, gentamicin, ampicillin, ciprofloxacin, ceftazidime, clindamycin, and the combinations of vancomycin and amikacin, vancomycin and ceftazidime, vancomycin and gentamicin, vancomycin and ampicillin, cefazolin and gentamicin, and ampicillin and gentamicin. RESULTS: No single antibiotic or combination was bactericidal (defined as 99.9% kill) to all isolates of Enterococcus. Gentamicin was bactericidal to all E. faecalis isolates. None of the tested antibiotics were bactericidal to vancomycin-resistant E. faecium. CONCLUSIONS: The time-kill profiles demonstrated that vancomycin and ceftazidime did not produce a 99.9% kill for E. faecalis in this small study. Gentamicin combined with either cefazolin or ampicillin had somewhat better bactericidal activity and should be considered as an alternative therapy. Novel therapy may be necessary to treat endophthalmitis because of vancomycin-resistant Enterococcus, depending on the susceptibility patterns of the individual isolate and the response to initial therapy.

Anti-Bacterial Agents↗
PubMed1995

Epidemiologic analysis of glycopeptide-resistant Enterococcus strains in neutropenic patients receiving prolonged vancomycin administration.

Vancomycin-resistant enterococci have been isolated with increasing frequency since 1988. Thus far, most of these resistant enterococci have belonged to the Enterococcus faecium species, and epidemiological studies have shown a wide diversity among interhospital and intrahospital isolates. This report presents an epidemiologic investigation of 25 vancomycin-resistant Enterococcus strains--24 Enterococcus faecium and one Enterococcus gallinarum--isolated from the stools or blood of adult patients receiving intravenous vancomycin prophylaxis during neutropenia and hospitalized in a single hematologic unit. Macrorestriction patterns of total DNA and of ribosomal DNA regions were used to analyze the strains. Strains produced different total DNA restriction fragment length polymorphism patterns after SmaI digestion. Ribotyping was less discriminative than pulsed-field gel electrophoresis. The results confirmed the genetic unrelatedness of the strains. Prolonged vancomycin administration, commonly used in hematologic units, could be involved in the selection of endogenous resistant enterococcal strains.

Anti-Bacterial Agents↗
PubMed1984

Role of enterococcus in intraabdominal sepsis.

Although enterococcus is well recognized as a pathogen in endocarditis, urinary tract infections, and biliary sepsis, its role in other forms of intraabdominal sepsis remains controversial. Antibiotics that lack activity against enterococcus can often be employed successfully in intraabdominal infections, even when enterococci are present as part of the polymicrobial flora. Furthermore, the enterococcus rarely emerges as a blood borne pathogen in such a setting. Breakthrough enterococcal septicemia may occur, however, in the immunodepressed host, particularly in the face of broad-spectrum antibiotic therapy not specific for enterococcus. Like infections with other opportunistic pathogens, enterococcal sepsis under these circumstances carries a high mortality. Specific antienterococcal drug therapy may be indicated as an adjunct to surgical management in selected patients with intraabdominal sepsis.

Abdomen↗
PubMed1997

Identification and characterization of proteolytic activity of Enterococcus spp. isolated from milk and Roncal and Idiazábal cheese.

Roncal and Idiazábal cheeses are manufactured from ewe's milk in the Autonomous Region of Navarre in Spain. Levels of enterococci are high in these cheeses and in other types of ewe's-milk cheeses. The present study has identified enterococci present in the milk used and in the Roncal and Idiazábal cheeses after 120 days of ripening. A total of 282 strains were isolated and identified, and the cytoplasmic and extracellular enzymatic activities of some of the strains were assessed. The dominating species were Enterococcus faecalis, which accounted for 85% of the total both in the milk as well as in the two types of cheese, and Enterococcus faecium, Enterococcus durans, and Enterococcus avium which were present in lower proportions. Aminopeptidase and proteinase activity levels in enterococci were low, and considerable variation between strains of the same species was recorded, highlighting the need to study individual strains when selecting the most suitable bacteria as a starter culture. Aminopeptidase activity levels for the enterococci were appreciably higher at pH 7 than at pH 5.5, hence aminopeptidase activity by enterococci would appear to be less significant in the normal manufacturing conditions of the two cheeses.

Aminopeptidases↗
PubMed1994

Investigation of the potential role of Enterococcus faecalis in the pathophysiology of experimental peritonitis.

Two nonfatal models of peritonitis differing by the duration and the severity of the disease were studied in rats by implantation of Escherichia coli and Bacteroides fragilis with or without increasing concentrations of Enterococcus faecalis. Results were evaluated at 3 or 6 days after inoculation. The highest enterococcal concentrations (10(9) cfu/mL) enhanced the severity of the infection, evident by increased emaciation, increased peritoneal counts of E. coli and B. fragilis, and increased frequency of E. coli and B. fragilis bacteremia compared with enterococcus-free animals. Six therapeutic regimens (low-dose amoxicillin + low-dose gentamicin, high-dose amoxicillin + high-dose gentamicin, pefloxacin, ornidazole, pefloxacin + ornidazole, imipenem + gentamicin) were tested. All treatments failed to eradicate E. faecalis except the combination pefloxacin + ornidazole, which achieved a significant reduction of local bacterial counts and suppressed bacteremia. Enterococcus played an important role in the mechanisms of bacterial synergy in experimental peritonitis. However, eradication of enterococcus did not seem possible by conventional antienterococcal therapy.

Abscess↗
PubMed1996

Augmented production of extracellular superoxide by blood isolates of Enterococcus faecalis.

To assess the frequency of extracellular superoxide (O-2) production by enterococci, multiple species were surveyed in a whole organism assay for their ability to reduce ferricytochrome c in a superoxide dismutase-inhibitable fashion. For stool and clinical enterococcal isolates and 12 type strains, only Enterococcus faecalis (87/91 isolates and ATCC 19433), Enterococcus faecium (5/13 isolates), Enterococcus casseliflavus (ATCC 25778), and Enterococcus gallinarum (ATCC 35038) produced extracellular O-2. Among 106 strains comprising 13 species of enteric gram-negative bacilli and gram-positive cocci, only Lactococcus lactis subspecies lactis produced extracellular O-2. Mean (+/-SE) rates of extracellular O-2 production in vitro by E . faecalis for isolates associated with bacteremia and endocarditis and for isolates from stool were 2.4+/-0.2, 1.9+/-0.2, 1.5+/-0.3 nmol of O-2 min(-1) 10(9) cfu(-1), respectively (P=.025, analysis of variance), suggesting an association between invasiveness and extracellular O-2 production.

Bacteremia↗
PubMed1996

Phenotypic and genotypic characterization of atypical Lactococcus garvieae strains isolated from water buffalos with subclinical mastitis and confirmation of L. garvieae as a senior subjective synonym of Enterococcus seriolicida.

During a survey of bacterial agents that cause subclinical mastitis in water buffalos, we isolated several strains of gram-positive cocci that appeared to be enterococci except that they grew very slowly at 45 degrees C and grew slowly in broth containing 6.5% NaCl. On the basis of the results of conventional physiologic tests, these strains were identified as Enterococcus durans. However, none of the strains reacted with the AccuProbe Enterococcus genetic probe. The whole-cell protein profiles of these organisms were compared with the profiles of Enterococcus and Lactococcus reference strains. apart from minor quantitative differences, the mastitis isolates had indistinguishable protein profiles that were similar to the profiles of the Lactococcus garvieae and Enterococcus seriolicida type strains. The results of DNA relatedness studies performed by using the hydroxyapatite method at 55 and 70 degrees C indicated that all of the mastitis isolates were related to the type strain of L. garvieae at the species level, despite the fact that they exhibited several uncommon phenotypic characteristics (growth at 45 degrees C, growth in broth containing 6.5% NaCl, and failure to produce acid from mannitol and sucrose). The high levels of DNA relatedness between strains of L. garvieae is a senior synonym of E. seriolicida, L. garvieae should be retained as the species name and strain ATCC 43921 should remain the type strain of this species.

Animals↗
PubMed2001

Enterococcus villorum sp. nov., an enteroadherent bacterium associated with diarrhoea in piglets.

The taxonomic positions of five enteroadherent bacterial pig isolates, showing phenotypic characteristics most similar to those of Enterococcus durans and Enterococcus hirae, were investigated in a polyphasic study that included 16S rDNA sequence analysis, DNA-DNA hybridizations, DNA base-ratio determinations, whole-cell protein fingerprinting, D11344-primed PCR typing and an extensive examination of phenotypic properties. The results demonstrated that the organisms represent a new species in the Enterococcus faecium species group, for which the name Enterococcus villorum sp. nov. is proposed. The type strain is LMG 12287T (= CCM 4887T).

Animals↗