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PubMed1994

Characterization of enterococci isolated from human and nonhuman sources in Brazil.

A total of 330 enterococci strains isolated from several human (272 strains) and animal (27) clinical specimens and environmental sources (31) in Brazil were identified to species level. Major human sources included urine (48.5%), blood (15.8%), and wounds (9.5%). Human isolates were identified as Enterococcus faecalis (90.0%), E. faecium (6.9%), E. gallinarum (1.1%), E. durans (0.8%), E. casseliflavus (0.4%), E. raffinosus (0.4%), and E. mundtii (0.4%). Strains isolated from animals were composed of E. hirae (40.7%), E. faecalis (33.3%), E. faecium (18.5%), and E. casseliflavus (7.5%). Among environmental isolates, 42.0% were E. faecalis, 35.4% E. faecium, 13.0% E. hirae, 6.4% E. casseliflavus, and 3.2% E. durans. Antimicrobial susceptibility tests were performed for 200 strains. Overall, high-level resistance (HLR) to aminoglycosides was found in 66 (33.0%) of the strains tested. HLR to gentamicin was detected in 11.5% of the strains, whereas 19.0% of the strains showed HLR to streptomycin and 26.0% showed HLR to kanamycin. Five (22.7%) of the E. faecium strains were resistant to ampicillin [minimum inhibitory concentration (MIC) > 32 micrograms/ml]. Vancomycin MIC50 and MIC90 were 2 and 4 micrograms/ml, respectively; only eight strains (identified as E. casseliflavus or E. gallinarum) had MIC of 8 micrograms/ml. No beta-lactamase activity was detected by the nitrocefin test.

Animals↗
PubMed2002

Proficiency of Italian clinical laboratories in detecting reduced glycopeptide susceptibility in Enterococcus and Staphylococcus spp. using routine laboratory methodologies.

OBJECTIVE: To assess the ability of 59 clinical microbiology laboratories distributed throughout Italy to correctly identify and detect reduced susceptibility to glycopeptides in staphylococci and VanA-, VanB- or VanC-mediated glycopeptide resistance in enterococci. METHODS: Eight test strains comprising three staphylococci (S. aureus ATCC 29212 and two vancomycin-intermediate S. haemolyticus [11105301, 10030683Y]) and five enterococci (E. faecalis ATCC 29212, E. faecalis ATCC 51299 VanB, E. faecium AIB40 VanA, E. faecalis V583 VanB and E. gallinarum AIB39 VanC1) were distributed to 59 Italian clinical microbiology laboratories. Each isolate was blind-coded, and laboratories were instructed to identify the strains and test isolates for susceptibility to teicoplanin and vancomycin using their standard methods. Results were assessed against consensus test results obtained by a reference laboratory. In addition, to complement data interpretation, laboratories were asked to provide retrospective routine test results from their respective hospitals. RESULTS: All 59 laboratories participating in the study completed the susceptibility testing and provided data for analysis. A total of 53 laboratories provided retrospective routine data. Overall, laboratories were able to identify isolates to the genus level successfully. E. gallinarum and S. haemolyticus posed problems for species identification, with only 40.6 and 71.2%, respectively, of results reported correctly; most incorrect results were reported as 'other species'. For enterococcal test strains, VanA phenotypes were detected correctly by 96.6% of laboratories; VanB by 30.5% (E. faecalis ATCC 51299) and 88.1% (E. faecalis V583); and VanC1 by 67.8%. For staphylococcal test strains, 28.8% (S. haemolyticus 11105301) and 23.7% (S. haemolyticus 10030683Y) of the laboratories were able to detect reduced susceptibility to vancomycin. Errors in detecting vancomycin resistance in VanB and VanC1 enterococci were made with all methods, most noticeably by disk diffusion users. For staphylococci, most errors in reporting vancomycin-intermediate resistance occurred with disk diffusion and Vitek (software version 5.04) users. Overall, considerably fewer errors occurred with the detection of teicoplanin resistance, especially for staphylococci. For 1999, routine results show that 41/1749 (2.4%) of E. faecium, 220/11 180 (2.0%) of E. faecalis, 29/24 927 (0.12%) of S. aureus and 54/22 102 (0.24%) of coagulase-negative staphylococci were reported as resistant to vancomycin. CONCLUSION: Italian laboratories are able to identify staphylococci and enterococci adequately, although all methodologies used have problems in identifying E. gallinarum and coagulase-negative staphylococci to the species level. While VanA phenotypes were efficiently detected, problems were experienced in detecting VanB and VanC phenotypes. The majority of laboratories were unable to detect reduced vancomycin susceptibility in staphylococci adequately, especially with disk diffusion and older Vitek systems. Teicoplanin appeared useful as a marker for detecting vancomycin resistance, particularly with disk diffusion. Should enterococcal VanB or staphylococcal glycopeptide-intermediate phenotypes become prevalent in Italy, it is likely that they would be under-detected. New systems under development, such as Vitek2, should improve this situation.

Anti-Bacterial Agents↗
PubMed2003

[Surveillance on gram-positive bacteria isolated from patients with hospital acquired infections or community acquired infections].

OBJECTIVE: To determine the drug-resistance rates of gram-positive cocci isolated from patients with hospital acquired infection (HAI) or community acquired infection (CAI) in 34 study wards of 13 hospitals located at different areas in China. METHODS: According to the previous protocol, from July 1(st) 2000 to June 30(th) 2001, a total of 2401 pathogenic strains were isolated from 13 hospitals. Among them, 805 strains of gram-positive cocci were collected for in vitro susceptibility test using international standard plate dilution method. According to the criteria of guidelines of NCCLS (2001), MIC(50) and MIC(90) were detected to represent the antibacterial activity of antimicrobial agents and R%, I%, and S%, were calculated to show the resistant, intermediate and susceptible rates of the bacteria to the compounds tested. RESULTS: The detectable rates of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) were 37.4% (89/238) and 33.8% (51/151) respectively. Among a total of 238 strains of S. aureus, 139 were isolated from patients with CAI and 37 were from HAI patients, the rate of MRSA from HAI patients (89.2%, 33/37) was significantly higher than that of MRSA from CAI patients (30.2%, 42/139) (P < 0.01). The total resistant rate of penicillin resistant Streptococcus pneumoniae (PRSP) was 26.7% (8/30), including a R% of 3.3% (1/30) and an I% of 23.3% (7/30). 331 strains of Enterococcus were isolated, including 178 strains from the study wards and 153 strains from other wards. The ratio of number of strains of E. faecalis to E. faecium was 6.8:1 (286/42). The rate of ampicillin resistant E. faecium (AREF) was 73.8% (31/42), significantly higher than the rate of ampicillin resistant E. faecalis (16.4%, 47/286). Neither strains of S. aureus nor strains of coagulase negative Staphylococcus were found resistant to vancomycin. No strains of Enterococcus were found resistant to vancomycin, the intermediate rates of E. faecalis and E. faecium to vancomycin were 3.5% (10/286) and 9.5% (4/42) respectively. All strains of Enterococcus were found 100% susceptible to teicoplanin. CONCLUSION: The resistance patterns of Gram-positive cocci including MRSA, PRSP, and AREF are similar to the results of the 1998 - 1999 surveillance. No strain of vancomycin-resistant Staphylococcus aureus, including VRSA and VISA or vancomycin resistant enterococcus, VRE is found in this study.

Anti-Bacterial Agents↗
PubMed2002

Physical and genetic map of Enterococcus faecium ATCC19434 and demonstration of intra- and interspecific genomic diversity in enterococci.

A physical map of the Enterococcus faecium ATCC19434 chromosome was constructed by NotI, I-CeuI and Sse8387I. The chromosome was a circular DNA of 2600 kb in size, and contained six rRNA operons (rrn). The locations and orientations of the six rrn operons and 24 different determinants were mapped. Genomes of three additional E. faecium strains were also analyzed by I-CeuI digestion, and the genome sizes were found to vary from 2550 to 2995 kb. We further investigated the genome sizes and number of rrn operons in four E. faecalis, one E. avium, and one E. durans strains. The genome sizes were larger than E. faecium: 3000-3250 kb in E. faecalis, 3445 kb in E. avium, and 3070 kb in E. durans. E. avium and E. durans contained six rrn operons as in E. faecium, but all the E. faecalis strains possessed four rrn operons.

Chromosomes, Bacterial↗
PubMed2000

[Resistance to antibiotics in clinical isolates of the genus Enterococcus].

The purpose of our study was to determine the prevalence of resistance in 114 clinical strains of enterococci. Identification was made using PASCO dehydrated panels and by the conventional method of Facklam and found the following: 92.1% E. faecalis, 7% E. faecium and 0.9% E. avium. The antibiotic susceptibility was determined by the PASCO system, and the minimum inhibitory concentrations of vancomycin, teicoplanin, gentamicin and streptomycin were determined by the agar dilution method. All the strains were susceptible to vancomycin and teicoplanin. We detected resistance to ampicillin in 4.4% of isolates, to penicillin in 6%, to tetracycline in 41.2%, to rifampicin in 12.3%, to chloramphenicol in 23.7%, to erythromycin in 66.7%, to ciprofloxacin in 53.5%, to gentamicin to a high level in 43.9%, and to streptomycin to a high level in 57%. E. faecium was associated with high-level resistance to gentamicin. E. faecium was more resistant than E. faecalis to quinolones, rifampicin, penicillin and ampicillin, and showed similar susceptibility to tetracycline and chloramphenicol. However, E. faecalis was more resistant than E. faecium to aminoglycosides, mainly to gentamicin.

Cross Infection↗
PubMed2003

Phenotypic and genotypic characterization of VanA Enterococcus isolated during the first nosocomial outbreak in Brazil.

We report the phenotypic and genotypic characterization of 50 VanA Enterococcus clinical isolates from infected patients and 97 isolates from colonized patients obtained during a nosocomial outbreak in a single hospital in São Paulo, Brazil during 1998. The identification of strains to the species level by conventional biochemical and phenotypic tests and by multiplex PCR assay had 100% agreement. Both E. faecalis and E. faecium were isolated from patients during this outbreak. The vanA genotype was confirmed by PCR. Antibiotic susceptibility testing showed that E. faecium isolates are generally less susceptible to antibiotics than E. faecalis. By PCR, 24 of 26 VRE strains tested carried the Tn1546 element. Pulsed-field gel electrophoresis identified five distinct patterns for E. faecalis (A, B, C, D, E) and three for E. faecium (M, N, and O). A single PFGE pattern was identified in the majority of strains of each species and does not discriminate between case and carrier isolates.

Anti-Bacterial Agents↗
PubMed1993

Identification and characterization of multiple species of vancomycin-resistant enterococci, including an evaluation of Vitek software version 7.1.

A total of 374 clinical isolates of Enterococcus spp. were characterized to determine the species distribution and vancomycin resistance. The ability of the Vitek system (bioMerieux Inc, Hazelwood, St. Louis, Mo.) to identify enterococci to the species level and to recognize vancomycin resistance by using computer software version 7.1 was evaluated. Conventional methods were used for identification and agar dilution was used for susceptibility testing, the results of which were as follows (presented as number of vancomycin-resistant isolates/number of members of that species identified): 219/234 E. faecium, 9/112 E. faecalis, 2/3 E. mundtii, 0/1 E. durans, 0/1 E. hirae, 0/1 E. raffinosis, and 0/1 E. avium. Ten enterococci were in the vancomycin-intermediate category (six E. gallinarum, two E. casseliflavus, and one each of E. faecium and E. faecalis). The Vitek GPI card correctly identified 98% of E. faecium isolates, 99% of E. faecalis isolates, and only two isolates of other enterococcal species. The GPS-TA card was 98% sensitive and 95% specific for the detection of vancomycin resistance, generating a total of four very major (1.6%) and five minor errors (1.3%).

Drug Resistance, Microbial↗
PubMed2006

Comparative study of vanA gene transfer from Enterococcus faecium to Enterococcus faecalis and to Enterococcus faecium in the intestine of mice.

Vancomycin-resistant enterococci represent a large reservoir in animals because of the use of avoparcin as a growth promoter in Europe. These strains of animal origin enter the food chain and can either colonize the human gut or transfer their resistance genes to the human microbiota. In this study, we compared the transfer of vancomycin resistance from resistant animal Enterococcus faecium to sensitive human Enterococcus faecalis and E. faecium. We analysed these transfers in dibiotic mice and human faecal flora-associated mice. VanA transfer from animal E. faecium to human E. faecalis occurred in dibiotic mice. The transconjugants appeared rapidly and persisted at levels between 3.0 and 4.0 log10 colony-forming units g(-1) of faeces. In human faecal flora-associated mice, vanA gene transfer was not detected towards E. faecalis but was possible between E. faecium strains. Our experiments revealed the possibility of vanA transfer from animal E. faecium to human E. faecalis in vitro and in vivo in the intestine of dibiotic mice. However, intraspecies transfer of vanA gene seems more common than interspecies transfer among enterococci.

Animals↗
PubMed1999

A comparison of polymerase chain reaction and phenotyping for rapid speciation of enterococci and detection of vancomycin resistance.

This study aimed to ascertain the ability of the microbiology laboratory to detect and identify catalase-negative Gram-positive cocci with particular reference to vancomycin-resistant enterococci (VRE). Twenty-seven reference strains and 42 prospectively collected catalase-negative Gram-positive cocci were screened by agar dilution breakpoint susceptibility and linked biochemical methods in routine use. Ability to speciate organisms was then compared using: (i) a multiplex polymerase chain reaction, designed to detect gene sequences specific to Enterococcus faecalis and E. faecium, and vancomycin resistance (van) genes; (ii) a commercial "API 20 strep" (iii) an algorithm using individual tests from a commercial API 20 strep strip; and (iv) the same algorithm utilising traditional phenotyping methods. All vancomycin resistant catalase-negative Gram-positive cocci were detected by an agar dilution screening plate containing 4 micrograms/ml of vancomycin. Polymerase chain reaction (PCR) detected all enterococci with van genes, speciated all vancomycin-sensitive E. faecalis and E. faecium isolates and excluded non-enterococcal vancomycin-resistant catalase-negative Gram-positive cocci. Algorithm-based methods speciated 41 of the 42 study isolates (98%). The API 20 strep correctly identified only 25 (60%) of these organisms, 38 of which were vancomycin-sensitive E. faecalis. VRE are detected by current screening methods for vancomycin-resistant catalase-negative Gram-positive cocci in this laboratory. API 20 strep, currently used to speciate catalase-negative Gram-positive cocci, is less reliable and should be replaced. Algorithm-based phenotyping by either method tested is more reliable for speciation than API 20 strep in its recommended form. Compared to the other methods tested, PCR is a rapid, accurate and inexpensive method of detecting and speciating vancomycin-resistant enterococci and it provides important extra information impacting on clinical therapy and infection control.

Algorithms↗
PubMed1999

Identification of enterococci and determination of their glycopeptide resistance in German and Austrian clinical microbiology laboratories.

OBJECTIVE: To determine exactly how German and Austrian routine laboratories perform tests for the identification of enterococci and determination of their glycopoptide resistance. METHODS: Six enterococcal test strains with different types of glycopeptide resistance (Enterococcus faecium, VanA; E. faecalis, VanA; E. faecium, VanB; E. faecalis, VanB; E. gallinarum, VanC1; E. casseliflavus, VanC2) were sent as anonymous isolates to 73 clinical microbiology laboratories (65 in Germany; eight in Austria). The participating laboratories had to identify the strains up to the species level and to determine their antibiotic susceptibilities to the glycopeptides vancomycin and teicoplanin by the test method(s) that are used daily in the corresponding laboratories. RESULTS: The analysis of the results received from 62 laboratories (56 from Germany, six from Austria) demonstrated that the most used routine method in susceptibility testing was the agar diffusion test, followed by the Etest, and the microbroth dilution procedure. The majority of participants had no difficulties in susceptibility testing with the VanA-type strains. However, the agar diffusion test was often not able to recognize clearly the VanB and VanC strains; some problems also arose with VanB isolates in the Etest. With the microbroth dilution method, the corresponding type of glycopeptide resistance was correctly determined in the majority of enterococcal test strains. Difficulties also arose in identification, especially with the VanC strains (E. gallinarum and E. casseliflavus), which were often falsely identified as E. faecium. The reasons for these errors are obviously based on the lack of important tests (such as motility and presence of a yellow pigment) in some commercially available identification test kits.

Journal Article↗
PubMed2004

Molecular epidemiology and antimicrobial susceptibility of Enterococci recovered from Brazilian intensive care units.

We studied the antimicrobial resistance and the molecular epidemiology of 99 enterococcal surveillance isolates from two hospitals of Brasilia, Brazil. Conventional biochemical tests were used to identify the enterococcal species and the disk diffusion method was used to determine their resistance profiles. Enterococcus faecalis (76%) and E. faecium (9%) were the most prevalent species. No enterococci showed the vanA or vanB vancomycin resistance phenotypes or genotypes. Only the intrinsically resistant species E. gallinarum (n=2) and E. casseliflavus (n=3) harbored the vancomycin-resistance genes vanC1 and vanC2/3, respectively. We found E. faecalis isolates with high-level resistance to gentamicin (22%) and streptomycin (8%) and both E. faecalis and E. faecium isolates with resistance to more than two antimicrobials (84% and 67%, respectively). Nine E. faecalis isolates (12%) were resistant to ampicillin; the minimal inhibitory concentration (MIC) values were 16 microg/mL (n=6) and 32 microg/mL (n=3). Among these ampicillin-resistant E. faecalis, seven were also resistant to gentamicin, ciprofloxacin, rifampin, penicillin, chloramphenicol, tetracycline and erythromycin. Pulsed-field gel electrophoresis classified those isolates in three different genotypes, suggesting dissemination of genetically related ampicillin-resistant E. faecalis strains among different patients.

Anti-Bacterial Agents↗
PubMed2004

Multicenter evaluation of use of penicillin and ampicillin as surrogates for in vitro testing of susceptibility of enterococci to imipenem.

Imipenem is approved by the U.S. Food and Drug Administration (FDA) for treatment of infections caused by Enterococcus faecalis. However, there are no NCCLS guidelines for testing susceptibility of enterococci against imipenem. To assess whether or not ampicillin or penicillin could be used as a surrogate for broth microdilution (BMD) testing of imipenem versus Enterococcus species, 633 strains of E. faecalis, E. faecium, and other enterococci isolated from blood cultures of patients at three geographically distinct university hospitals were tested by the NCCLS BMD and disk diffusion (DD) methods. Using FDA susceptibility breakpoints for imipenem and NCCLS breakpoints for penicillin and ampicillin, categorical agreement (CA) for penicillin-imipenem and ampicillin-imipenem tested with E. faecalis and E. faecium by BMD was >/=94% but was </=90% for other enterococci. Using the DD method, CA for ampicillin-imipenem tested with E. faecalis and E. faecium was >/=98% and was 92% for other enterococci; CA for penicillin-imipenem was 91% for E. faecalis, 98% for E. faecium, and 87% for other enterococci. Further analysis showed that testing E. faecalis with ampicillin resulted in no false-susceptible (FS) or false-resistant (FR) results by BMD, no FS results by DD, and a single FR result by DD (0.2%), whereas testing with penicillin resulted in no FS results by BMD or DD and two FR results by BMD (0.4%). For E. faecium and other enterococci, the combination of FS and FR results was such that surrogate testing with penicillin or ampicillin appears not to be sufficiently reliable to be used clinically. We conclude that ampicillin is an accurate predictor of the in vitro activity of imipenem against E. faecalis.

Ampicillin↗
PubMed2004

Occurrence, structure, and mobility of Tn1546-like elements in environmental isolates of vancomycin-resistant enterococci.

The occurrence, structure, and mobility of Tn1546-like elements were studied in environmental vancomycin-resistant enterococci (VRE) isolated from municipal sewage, activated sludge, pharmaceutical waste derived from antibiotic production, seawater, blue mussels, and soil. Of 200 presumptive VRE isolates tested, 71 (35%) harbored vanA. Pulsed-field gel electrophoresis analysis allowed the detection of 26 subtypes, which were identified as Enterococcus faecium (n = 13), E. casseliflavus (n = 6), E. mundtii (n = 3), E. faecalis (n = 3), and E. durans (n = 1) by phenotypic tests and 16S ribosomal DNA sequencing. Long PCR-restriction fragment length polymorphism (L-PCR-RFLP) analysis of Tn1546-like elements and PCR analysis of internal regions revealed the presence of seven groups among the 29 strains studied. The most common group (group 1) corresponded to the structure of Tn1546 in the prototype strain E. faecium BM4147. Two novel L-PCR-RFLP patterns (groups 3 and 4) were found for E. casseliflavus strains. Indistinguishable Tn1546-like elements occurred in VRE strains belonging to different species or originating from different sources. Interspecies plasmid-mediated transfer of vancomycin resistance to E. faecium BM4105 was demonstrated for E. faecalis, E. mundtii, and E. durans. This study indicates that VRE, including species other than E. faecium and E. faecalis, are widespread in nature and in environments that are not exposed to vancomycin selection and not heavily contaminated with feces, such as seawater, blue mussels, and nonagricultural soil. Tn1546-like elements can readily transfer between enterococci of different species and ecological origins, therefore raising questions about the origin of these transposable elements and their possible transfer between environmental and clinical settings.

Animals↗
PubMed1992

Antimicrobial susceptibility patterns of common and unusual species of enterococci causing infections in the United States. Enterococcal Study Group.

We collected 705 isolates of enterococci (1 per patient) from cultures of a variety of anatomic sites from patients at eight tertiary-care hospitals in six geographic regions of the United States. A total of 632 (90%) Enterococcus faecalis, 58 (8%) E. faecium, 5 E. gallinarum, 4 E. avium, 3 E. casseliflavus, 1 E. raffinosus, and 1 E. hirae isolate and 1 biochemical variant of E. faecalis were identified; 606 (86%) of these isolates were associated with clinical infections. The most common sites of isolation were the urinary tract (402 [57%]), nonsurgical wounds (94 [13%]), the bloodstream (74 [10%]), and surgical wounds (62 [9%]). High-level resistance to gentamicin or streptomycin or both was detected in 265 (38%) of the isolates. We identified two E. faecalis isolates resistant to vancomycin (MICs, 32 and 128 micrograms/ml) and 11 beta-lactamase-producing E. faecalis isolates. E. faecium isolates were significantly more resistant than E. faecalis isolates to penicillin, ampicillin, piperacillin, imipenem, and ciprofloxacin (P less than 0.001). The MICs for the 15 non-E. faecalis, non-E. faecium enterococci indicated variable resistance to ciprofloxacin and the penicillins. Antimicrobial susceptibility patterns vary among species of enterococci, and these organisms, while commonly resistant to high-level aminoglycosides, can also acquire resistance to vancomycin or the ability to produce beta-lactamase. Because of these diverse antimicrobial resistance mechanisms, successful treatment and control of enterococcal infections with current antimicrobial agents are becoming increasingly difficult.

Adolescent↗
PubMed2000

[Prevalence of Enterococcus faecalis and Enterococcus faecium with high resistance to aminoglycosides in the cities of Resistencia and Corrientes, Republic of Argentina].

BACKGROUND: The objective of this study was characterize the prevalence of high-level aminoglycosides resistance (HLRA) in Enterococcus faecalis and E. faecium, determine the relationship between high-level gentamicin resistance (HLGR) and other aminoglycosides, and their distribution according clinical samples (blood, urine and others). MATERIALS AND METHOD: A total of 177 strain (157 E. faecalis and 20 E. faecium) isolated from 1996 to 1998 were studied. They were identified by using classic methods. Their susceptibility to gentamicin, streptomycin, and kanamycin was tested by the disk diffusion technique using high-level disks in agar Müller Hinton. RESULTS: E. faecalis showed HLRG of 28.7%, streptomycin 28.7% and kanamycin 37.6%, E. faecium showed 50%, 40%, and 60% respectively. The strains with HLRA have a tendency to high-level resistances to streptomycin and kanamycin (p < 0.0005). Statistical analysis demonstrated significative differences among strains with HLRA isolated from blood, urine and other clinical samples (p < 0.0005 to gentamicin and streptomycin and 0.004 < p < 0.007 to kanamycin). CONCLUSIONS: The prevalence of HLRA enterococci found in the area os this study, justify its detection, particularity in cases of serious infections.

Aminoglycosides↗
PubMed2004

Comparison of phenotypic and genotypic taxonomic methods for the identification of dairy enterococci.

The purpose of the study was to assess the phenotypic and genotypic taxonomic congruence in order to allow species allocation of dairy enterococci. A total of 364 enterococci isolated from ewes'milk and cheese from four Portuguese Registered Designation of Origin areas and 25 type and reference strains of Enterococcus spp. were characterized by a polyphasic taxonomical approach involving 40 physiological and biochemical tests, whole-cell protein profiles, amplification of 16S-23S intergenic spacer regions (ITS-PCR) and subsequent restriction analysis (ARDRA). Ribotyping was also performed with reference strains and a subset of 146 isolates. Numerical hierarchic data analysis showed that single-technique identification levels increase from the physiological and biochemical tests to the protein approach, being lower with ITS/ARDRA and ribotyping. Cross-analysis confirmed a higher unmatching level in all pairwise combinations involving physiological and biochemical data. Whole-cell protein profiles followed by ITS/ARDRA identified 89% of the enterococci. Reliable identification of enterococci from milk and cheese could be obtained by analysis of whole-cell protein profiles. ITS-PCR can be used to confirm E. durans and E. faecium and ARDRA further confirms E. faecalis. Results revealed E. faecalis, E. durans, E. hirae and E. faecium as the prevalent species, although species prevalence showed some degree of variation among the areas.

Animals↗
PubMed2006

Safety and potential risks of enterococci isolated from traditional fermented capers.

A collection of 17 enterococci isolates obtained from fermentations of capers (the fruits of Capparis sp.) were investigated for incidence of known virulence determinants, antibiotic resistance and production of biogenic amines. Molecular identification revealed the presence of Enterococcus faecium (nine isolates), Enterococcus faecalis (4), E. avium (3) and Enterococcus casseliflavus/flavescens (1). Alpha-haemolytic activity was detected in two E. avium and one E. faecalis isolates, and beta-haemolytic activity was detected in E. casseliflavus/flavescens. The haemolytic component cylB was detected by PCR amplification in three non-haemolytic isolates and in E. casseliflavus/flavescens. The collagen adhesin ace gene and the endocarditis associated antigen gene efaA(fm) were detected in two isolates each. Genes encoding sex pheromone precursors (cpd, cob, ccf) were detected in E. faecalis and E. casseliflavus/flavescens. Other presumed virulence genes (agg, gelE, cylM, cylA and efaA(fs)) were not detected. All isolates were resistant to rifampicin, erythromycin and ciprofloxacin, and some were also resistant to quinupristin/dalfopristin, tetracycline, levofloxacin, gentamicin and streptomycin. Vancomycin resistance was not detected. Tyrosine decarboxylation was detected in all E. faecium isolates. Given the high resistance of enterococci to environmental conditions, and their implication in opportunistic infections, the incidence of potential virulent enterococci in foods (especially those of a higher risk-like home-made foods) should be carefully studied.

Antigens, Bacterial↗
PubMed1990

Evidence for the translocation of Enterococcus faecalis across the mouse intestinal tract.

The pathogenesis of Enterococcus (Streptococcus) faecalis was studied in mice with E. faecalis intestinal overgrowth (10(9) - 10(10) per gram of cecum) induced by metronidazol and streptomycin treatment coupled with oral inoculation of E. faecalis. E. faecalis was recovered from the mesenteric lymph nodes, liver, and spleen; mortality was noted in 8 (13%) of 62 mice after 14 days of E. faecalis intestinal overgrowth. Light, immunofluorescent, and electron (scanning and transmission) microscopy of ileal tissue was used in an attempt to localize E. faecalis translocating across intestinal tissue. Dense coccal bacteria were observed in the intestinal lumen, and the epithelium appeared intact. Coccal bacteria were observed adherent to the microvillus border of the entire villous epithelium, including the deeper regions of the intestinal crypts. Immunofluorescence localized E. faecalis within columnar epithelial cells, lamina propria, submucosa, and muscularis externa (including the lumen of small vessels). Transmission electron microscopy localized coccal bacteria within vacuoles in the cytoplasm of intact epithelial cells. These results indicated that E. faecalis could translocate across an intact intestinal tract and cause systemic infection and death. In this model, the intestinal epithelial cell appeared to be a portal of entry in the pathogenesis of systemic E. faecalis infection.

Animals↗