gelE Genes Research Articles

English

Enterococcus faecium has become an increasingly important nosocomial pathogen due to formation of biofilms on several surfaces. Sixty one (61) E. faecium strains isolated from blood, urine and fecal were assessed for biofilm production, the effect of different glucose concentration on biofilm production and also the presence of esp, fsr and gelE genes. Pulsed field gel electrophoresis (PFGE) method was performed to show chromosomal similarities and also to determine correlation between biofilm formation ability and genetic identity of E. faecium strains. It was observed that glucose concentration of the medium and incubation period can affect biofilm formation of the bacteria. When tested strains were incubated in a medium containing 1% glucose for 48 h, 66.66% of urine isolates, 60.71% fecal isolates and 25% of blood isolates produced strong biofilm structures. esp-positive strains (80% of the all isolates) were also identified as strong biofilm producers compared to esp-negative isolates. As a result of PFGE analyses, isolates numbered 14 (isolated from fecal sample) and 81 (isolated from blood sample) were classified in minor group B at a level of 48% similarity. Out of these two isolates, all the isolates were included in major group A with 43% similarity level and this group was subdivided into six subgroups. Key words: Enterococcus faecium, biofilm, Pulsed Field Gel Electrophoresis (PFGE), esp, fsr, gelE.

The relationship between virulence factors and vancomycin resistance among Enterococci collected from food and human samples in Southern Turkey

Bu çalışmanın amaçları, Türkiye’nin güneyinde gıda kaynaklı 51 adet Enterococcus spp. ile insan kaynaklı 50 adet Enterococcus faecium izolatlarının potansiyel virülans faktörlerinin, vankomisin direnç özelliklerinin prevalansının belirlenmesi ve vankomisin direnci ile virülans faktörler arasında muhtemel ilişkinin değerlendirilmesidir. İzolatlarının identifikasyonu Vitek-II sistemiyle, antimikrobiyel direnç testleri Vitek-II sistemi ve disk difüzyon metodlarıyla çalışıldı. vanA ve vanB ile sitolizin (cylA), agregasyon faktörü (asa1), jelatinaz (gelE), entrokok yüzey proteini (esp), hiyolüronidaz (hyl), genlerinden oluşan enterokokal virülans genler Polimeraz Zincir Reaksiyonu (PCR) metoduyla, hemolizin üretimi fenotipik yöntemle çalışıldı. Bir izolat dışında, gıda izolatlarının hiçbiri vankomisine dirençli değildi ve hiçbiri vanA ve vanB geni taşımamaktaydı. Klinik izolatların tümü vankomisine dirençliydi ve bu izolatların %84’ü vanA, %2’si vanB genlerini taşımakta; %14’ü vanA ve vanB genlerini taşımamaktaydı. cylA geni dışındaki test edilen diğer virülans genler ve vankomisin direnci, klinik izolatlarda daha yüksekti ve çoklu virülans genler ile vankomisin direnci arasında pozitif bir korelasyon gözlendi. Tüm izolatlar arasında esp gen pozitifliği ile vankomisin direnci, E. faecium türlerinde ise esp, hyl gen pozitiflikleri ile vankomisin direnci arasında pozitif bir korelasyon olduğu görüldü. Ayrıca, iki gıda ve bir intestinal enterokok suşunda ‘’sessiz cylA geni’’ bulundu. Bulgularımıza göre, virülans faktörler vankomisin direncine paralel olarak artabilir ve gıda kaynaklı enterokoklar gelE, asa1, hyl virülans genlerinin yayılmasında potansiyel kaynak olabilir. Sonuç olarak, gıda kaynaklı enterokoklarda esp ve hyl gen varlığı dikkatle izlenmelidir

Molecular characterization of vancomycin-resistant enterococci in Serbia: Intensive care unit as the source

The purpose of this study was to evaluate the molecular relatedness of clinical isolates of vancomycin-resistant enterococci (VRE) collected from patients of the Clinic for Infectious and Tropical Diseases in Belgrade. Among 40 isolates available for the investigation, 36 were identified as Enterococcus faecium, whereas 2 were Enterococcus faecalis and Enterococcus raffinosus, respectively. Pulsed-field gel electrophoresis (PFGE) typing revealed 21 strain types, comprising 7 clusters which contained at least two isolates and 14 unique PFGE patterns. Although we searched for pathogenicity factor genes (gelE, cylB, asa1, efaAfs, esp, cpd, cob) in representatives of all macro-restriction patterns, they have been confirmed in only one clone of E. faecalis. Genes esp and hyl, commonly found in E. faecium, were yilded in 10 macro-restriction patterns of this species, and their presence could not be ascribed to clonally related strains (p = 0.05). All VRE isolates were multiresistant and positive for vanA gene. Twenty strains of VRE and 6 clusters obtained from Intensive care unit (ICU) are proof of intensive transmission of these microorganisms at this department. The results of this study suggest wide genotypic variability among the clinical VRE isolates, but also intrahospital dissemination of some of them.

Detection of virulence genes and biofilm formation of Enterococci strains isolated from blood samples

Objective To detect the main virulence genes and biofilm formation of Enterococci strains isolated from blood samples .Methods Twenty-eight strains of Enterococcus faecalis （ E.faecalis） and 54 strains of Enterococcus faecium （ E.faecium） were collected from blood samples .Five main virulence genes （asa1, esp, hyl, cylA and gelE） were detected by multiplex PCR.Biofilm formation was investigated by using microtiter dish biofilm formation assay .Results All E.faecalis strains were positive for at least one kind of virulence genes , of which 14 strains were concurrently positive for asa1, esp, cylA and gelE.asa1, cylA and gelE were only detected in E.faecalis strains, while hyl gene only existed in E.faecium strains. Twenty-seven strains of E.faecium were esp positive, of which 12 strains were both hyl and esp positive. None of the 5 virulence genes were identified in 10 strains of E.faecium.85.7% of E.faecalis strains and 63.0%of E.faecium strains could form biofilm.Conclusion Compared with E.faecium strains, more types of virulence genes were detected in E.faecalis strains with higher positive rates .Moreover , E.faecalis strains were more likely to form biofilms than E.faecium strains. Key words: Enterococcus; Virulence gene; Multiplex PCR; Biofilm

The marine environment as a reservoir of enterococci carrying resistance and virulence genes strongly associated with clinical strains

To gain insights into the relationships and the genetic exchange among environmental and clinical enterococci, 59 strains (29 from marine aquaculture sites and 30 from clinical settings) resistant to tetracycline, erythromycin, ampicillin and/or gentamicin were analysed for the antibiotic resistance tet(M), tet(L), tet(O), erm(A), erm(B), mef blaZ, aac(6')-Ie aph(2″)-Ia and virulence gelE, cylB, efaA and esp genes, and for the copper resistance gene tcrB. Antibiotic resistance and virulence genes were detected more frequently in clinical than in environmental enterococci; the opposite was true for copper resistance. Conjugation experiments demonstrated the transfer of antibiotic resistance genes from marine to clinical enterococci in interspecific mating and the uncommon joint transfer of tet(L) and erm(B). Enterobacterial repetitive intergenic consensus polymerase chain reaction typing evidenced a cluster (90% similarity) encompassing strains carrying multiple antibiotic resistance genes from both sets; the others marine isolates exhibited polyclonality and bore tcrB. Our results demonstrate that antibiotic-resistant marine enterococci bear antibiotic resistance genes transferable to humans and suggest that copper resistance, not observed among clinical strains, may be useful for survival in the environment, whereas virulence genes likely confer no advantage to enterococcal populations adapted to a lifestyle outside the host.

Bacteriocinogenic potential and safety evaluation of non-starter Enterococcus faecium strains isolated from home made white brine cheese

Four LAB strains, isolated from Bulgarian home made white brine cheese, were selected for their effective inhibition against Listeria monocytogenes. According to their biochemical and physiological characteristics, the strains were classified as members of Enterococcus genus, and then identified as Enterococcus faecium by 16S rDNA sequencing.Their bacteriocin production and inhibitory spectrum were evaluated together with the occurrence of several bacteriocin genes (entA, entB, entP, entL50B). Their virulence potential and safety was assessed both using PCR targeted to the genes gelE, hyl, asa1, esp, cylA, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc and by phenotypical tests for antibiotic resistance, gelatinase, lipase, DNAse and α- and β-haemolysis. The E. faecium strains harboured at least one enterocin gene while the occurrence of virulence, antibiotic resistance and biogenic amines genes was limited.Considering their strong antimicrobial activity against L. monocytogenes strains, the four E. faecium strains exhibited promising potential as bio-preservatives cultures for fermented food productions.

Genetic characterization of antibiotic resistance and virulence factors in Enterococcus spp. from Japanese retail ready-to-eat raw fish

Little information is available on the diversity and distribution of resistance and virulence factors in enterococci isolated from retail fish. In this study, 200 samples of retail ready-to-eat raw fish (sashimi) collected from the Japanese prefecture of Hiroshima were analyzed for incidence of Enterococcus spp. We recovered 96 enterococcal isolates from 90 (45%, 90/200) samples. Fifty-six strains were identified at the species level: E. faecalis (n = 31), E. faecium (n = 7), E. casseliflavus (n = 7), E. gallinarum (n = 3), E. phoeniculicola (n = 4), E. raffinosus (n = 2), E. saccharolyticus (n = 1), and E. gilvus (n = 1). Twenty-five (26%, 25/96) strains carried antibiotic resistance genes. These included the tet(M), tet(L), tet(K), erm(B), msr(A/B), aph(3′), and blaZ genes, which were detected in 12.5%, 9.3%, 2%, 14.5%, 1%, 1%, and 2% of isolates, respectively. The virulence genes gelE and asa1 were detected in 31 and 24 E. faecalis strains, respectively. Both genes were detected in one E. faecium strain. In conclusion, this is the first study to underscore the importance of sashimi as not only a reservoir of Enterococcus spp. carrying resistance and virulence genes, but also a reservoir for unusual Enterococcus spp.

Presence of virulence factors in Enterococcus faecalis and Enterococcus faecium susceptible and resistant to vancomycin

Despite the increasing importance of Enterococcus as opportunistic pathogens, their virulence factors are still poorly understood. This study determines the frequency of virulence factors in clinical and commensal Enterococcus isolates from inpatients in Porto Alegre, Brazil. Fifty Enterococcus isolates were analysed and the presence of the gelE, asa1 and esp genes was determined. Gelatinase activity and biofilm formation were also tested. The clonal relationships among the isolates were evaluated using pulsed-field gel electrophoresis. The asa1, gelE and esp genes were identified in 38%, 60% and 76% of all isolates, respectively. The first two genes were more prevalent in Enterococcus faecalis than in Enterococcus faecium, as was biofilm formation, which was associated with gelE and asa1 genes, but not with the esp gene. The presence of gelE and the activity of gelatinase were not fully concordant. No relationship was observed among any virulence factors and specific subclones of E. faecalis or E. faecium resistant to vancomycin. In conclusion, E. faecalis and E. faecium isolates showed significantly different patterns of virulence determinants. Neither the source of isolation nor the clonal relationship or vancomycin resistance influenced their distribution.

Presence of virulence factors in Enterococcus faecalis and Enterococcus faecium susceptible and resistant to vancomycin

Despite the increasing importance of Enterococcus as opportunistic pathogens, their virulence factors are still poorly understood. This study determines the frequency of virulence factors in clinical and commensal Enterococcus isolates from inpatients in Porto Alegre, Brazil. Fifty Enterococcus isolates were analysed and the presence of the gelE, asa1 and esp genes was determined. Gelatinase activity and biofilm formation were also tested. The clonal relationships among the isolates were evaluated using pulsed-field gel electrophoresis. The asa1, gelE and esp genes were identified in 38%, 60% and 76% of all isolates, respectively. The first two genes were more prevalent in Enterococcus faecalis than in Enterococcus faecium, as was biofilm formation, which was associated with gelE and asa1 genes, but not with the esp gene. The presence of gelE and the activity of gelatinase were not fully concordant. No relationship was observed among any virulence factors and specific subclones of E. faecalis or E. faecium resistant to vancomycin. In conclusion, E. faecalis and E. faecium isolates showed significantly different patterns of virulence determinants. Neither the source of isolation nor the clonal relationship or vancomycin resistance influenced their distribution.

Expression of quorum-sensing related genes during Enterococcus faecalis biofilm formation

To investigate the relationship between the expression of the quorum-sensing related genes during Enterococcus faecalis(Ef) biofilm formation. Ef biofilms model was established in vitro and film formation process was observed by confocal laser scanning microscope at 6, 12, 24 and 48 hours respectively.Quantification of biofilms was achieved by staining with crystal violet.Real-time fluorescence quantitative PCR method was used to detect the expression of fsrB, gelE and sprE genes in the process of Ef biofilm formation. A lot of live and dead bacteria unevenly distributed in Ef biofilm. The quantity of biofilms increased with time within 24 hours and was 0 h:0.00 ± 0.00, 6 h:1.09 ± 0.13, 12 h:2.10 ± 0.79, 24 h:3.30 ± 0.13, which was significantly different among the 4 time period(P < 0.05). The quantity of biofilm at 48 h(3.51 ± 0.01) increased slightly compared with 24 h(3.30 ± 0.13) , but did not show significant difference.Quantitative real-time PCR showed that the expression of quorum-sensing related fsrB increased with time within 24 hours and was 0 h:9.98 ± 0.46, 6 h:23.45 ± 1.13, 12 h:47.30 ± 2.49, 24 h: 331.30 ± 2.18, which was significantly different among the 4 time period(P < 0.05). The expression of gelE was 0 h: 6.54 ± 0.73, 6 h: 14.26 ± 1.24, 12 h: 37.47 ± 2.35, 24 h:264.80 ± 5.10(P < 0.05). The expression of sprE was 0 h: 7.72 ± 0.74, 6 h: 21.15 ± 0.96, 12 h:49.87 ± 3.18, 24 h:441.89 ± 7.74, which was significantly different among the 4 time period(P < 0.05). The fsrB, gelE and sprE genes are closely related to the biofilm formation in Ef.

Safety Assessment of Enterococcus faecium and Enterococcus faecalis Strains Isolated from Turkish Tulum Cheese

AbstractThe aim of this study was to evaluate several genetic and phenotypic traits of clinical significance in 21 Enterococcus faecium and seven E. faecalis strains previously isolated from Turkish Tulum Cheese. Enterococcus strains were tested for the presence of 14 virulence genes and two vancomycin resistance genes by polymerase chain reaction (PCR). Biogenic amine production was also investigated by decarboxylase medium and PCR. Investigation of virulence factors by PCR amplification revealed the presence of genes encoding for gelatinase (gelE), cell wall adhesin (efaAfm and efaAfs), sex pheromone (ccf), cell wall‐associated protein (espfm and espfs) and aggregation substance (agg). Other presumed virulence genes (cpd, cob, cad, ace, cylM, cylB and cylA) were not detected. At least one virulence gene was detected in all strains. The ccf (85.7%), efaAfm (75.0%) and gelE (32.1%) were detected most frequently present virulence genes in enterococcal strains. Phenotypic gelatinase testing revealed the existence of apparently silent gelE gene. None of the strains carried the vanA and vanB genes. Enterococcus strains did not decarboxylate histidine, lysine or ornithine, but the majority of strains (92.9%) produced tyramine from tyrosine. The tyrosine decarboxylase gene (tdc) was detected in all tyraminogenic strains.Practical ApplicationEnterococci are lactic acid bacteria that are important both in food and clinical microbiology. Enterococci species especially E. faecium and E. faecalis play an important role in the development of sensory characteristics of different traditional fermented foods such as dairy and meat products. On the other hand, E. faecium and E. faecalis are recognized as nosocomial pathogens. Results of this study indicated that E. faecium and E. faecalis strains isolated from Turkish Tulum Cheese carried some virulence genes and most of them produce tyramine. The findings of our study suggest that E. faecium and E. faecalis strains isolated from Turkish Tulum Cheese may be potential risk factors for consumer health. For this reason, use of Enterococcus strains as starter cultures requires thorough safety evaluation.

Molecular characterization of high-level gentamicin-resistant Enterococcus faecalis from chicken meat in Korea

Because the intrinsically antimicrobial-resistant Enterococcus has acquired high-level aminoglycoside resistance genes, treating enterococcal infections is difficult. In this study, of the 101 food-borne Enterococcus faecalis isolates collected from retail chicken meat between 2003 and 2010, 11 high-level gentamicin-resistant (HLGR) E. faecalis isolates (MICs>2,048μg/mL) were found. Molecular characterization was performed to determine the basis of this resistance. All HLGR E. faecalis isolates encoded aac(6′)-Ie–aph(2″)-Ia and harbored at least 3 virulence traits in the asa1, esp, gelE, efaA, ace, and cylA genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were performed to characterize their molecular epidemiology. A total of 8 sequence types (STs), including 3 novel STs, were identified (ST35, ST82, ST116, ST202, ST300, ST403, ST407, and ST420). ST82, which is associated with amyloid arthropathy in poultry, was the most prevalent ST among HLGR E. faecalis isolates (4 out of 11 isolates, 36.4%); all other STs were identified in the isolates as well. The STs of food-borne HLGR E. faecalis in this study have been confirmed as corresponding to clinical isolates in the MLST database (DB), except for ST300 and the new STs. Three out of 11 isolates belonged to CC116, including ST116, ST407, and ST420. This study characterized HLGR E. faecalis isolates and provided evidence for the spread of HLGR E. faecalis with virulence factors to chicken sources in Korea. The emergence of food-borne HLGR E. faecalis suggests that chicken could be a potential source of transmission of antimicrobial resistance and virulence factors.

Detección de genes de virulencia en cepas de Enterococcus faecalis susceptibles y resistentes a aminoglucósidos

Enterococcus spp. is an important cause of nosocomial infections A number of virulence factors that may enhance its ability to colonize have been described. Enterococcus is capable of acquiring resistance genes, including high-level resistance (HLR) to aminoglycoside antibiotics. to investigate the prevalence of genes encoding virulence factors in aminoglycosides susceptible and resistant E. faecalis. A total of 80 E. faecalis isolates from clinical (n: 52) and poultry samples (n: 28) were included in this study. Bacterial identification was performed by biochemical tests and phenotypificationwas done using the Phene-PlateTM system. Susceptibility to different antimicrobial agents was determined by the agar dilution method. Virulence genes aceI, agg, gelE and efaA were detected by multiplex PCR. All isolates were susceptible to vancomycin and ampicillin. HLR to gentamicin (13.5%) and streptomycin (9.6%) was detected only in clinical isolates. The phenotyping revealed a great diversity of PhP-types, but only one clone with 7 strains of similar characteristics was found. The efaA gen was detected in 100% of the isolates. aceI gene was present in 94.2% and 75%, agg gene in 73.1%, and 67.9%, and gelE gene in 57.5% and 28.6% of the clinical and chicken isolates, respectively. Only 6 strains with HLR to aminoglycosides, belonging to the same phenotype, had the aceI, agg, gelE and efaA genes. E. faecalis with virulence genes and HLR to aminoglycosides were isolated from clinical and chicken samples in Antofagasta. More studies will be necessary to establish an association.

Virulence factors ofEnterococcusstrains isolated from patients with inflammatory bowel disease

To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n = 16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of the asa1 gene and the gelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain of Enterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent among Enterococcus strains isolated from children with IBD than in control strains. Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.

Species distribution, antibiotic resistance and virulence traits in enterococci from meat in Tunisia

Antimicrobial resistance and the mechanisms implicated were studied in 119 enterococci from 105 meat samples from Tunisian markets. Almost 24.5% of recovered enterococci showed resistance against four or more antimicrobial agents and these isolates were identified to the species level. Enterococcus faecalis was the most prevalent species (41%). High percentages of erythromycin and tetracycline resistances were found among our isolates, and lower percentages were identified to aminoglycosides, ciprofloxacin and chloramphenicol. All tetracycline-resistant isolates carried the tet(M) and/or tet(L) genes. The erm(B) gene was detected in 78.5% of erythromycin-resistant isolates, ant(6)-Ia gene in 58.8% of streptomycin-resistant isolates, and cat(A) gene in one chloramphenicol-resistant isolate. Forty-eight isolates carried the gelE gene and exhibited gelatinase activity. The hyl and esp genes were detected in one and three Enterococcus faecium isolates, respectively. Streptomycin-resistant isolates showed a high genetic diversity by PFGE and MLST. Meat might play a role in the spread through the food chain of enterococci with these virulence and resistance characteristics to humans.

Characterization and risk factors of vancomycin-resistantEnterococci(VRE) among animal-affiliated workers in Malaysia

This study determined the risk factors and characteristics of vancomycin-resistant Enterococci (VRE) among individuals working with animals in Malaysia. Targeted cross-sectional studies accompanied with laboratory analysis for the identification and characterization of resistance and virulence genes and with genotype of VRE were performed. VRE were detected in 9·4% (95% CI: 6·46-13·12) of the sampled populations. Enterococcus faecium, Enterococcus faecalis and Enterococcus gallinarum were isolated, and vanA was detected in 70% of the isolates. Enterococcus faecalis with vanB was obtained from one foreign poultry worker. At least one virulence gene was detected in >50% of Ent. faecium and Ent. faecalis isolates. The esp and gelE genes were common among Ent. faecium (58·3%) and Ent. faecalis (78%), respectively. The VRE species showed diverse RAPD profiles with some clustering of strains based on the individual's background. However, the risk factors found to be significantly associated with the prevalence of VRE were age (OR: 5·39, 95% CI: 1·98-14·61) and previous hospitalization (OR: 4·06, 95% CI: 1·33-12·35). VRE species isolated from individuals in this study have high level of vancomycin resistance, were genetically diverse and possessed the virulence traits. Age of individuals and history of hospitalization rather than occupational background determined VRE colonization. This study provides comprehensive findings on the epidemiological and molecular features of VRE among healthy individuals working with animals.

Characterization of Enterococcus faecium isolates and first report of vanB phenotype–vanA genotype incongruence in the Middle East

We aimed to characterize the vancomycin genotype/phenotype, carriage of putative virulence genes, and genetic relatedness of Enterococcus faecium isolates in Saudi Arabia. E. faecium isolated from inpatients at our medical center were studied. Sensitivity to ampicillin, linezolid, teicoplanin, quinupristin/dalfopristin, tetracycline, and ciprofloxacin was determined. The presence of van genes and virulence genes for aggregation substance (Asa-1), enterococcal surface proteins (esp), cytolysin (cylA, cylL, cylM), gelatinase (gelE), E. faecium endocarditis antigen (EfaA( fm )), hyaluronidase (hyl), and collagen adhesion (Ace) was assessed. Genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE). Twenty-nine E. faecium isolates were obtained and the majority of isolates (n/N = 22/29) were from stool specimens. PFGE analysis identified eight pulsotypes (A-H) based on 80% similarities. Isolates were represented in five major pulsotypes: type A (n = 5), type B (n = 3), type D (n = 6), type E (n = 5), and type F (n = 7). All isolates were vanA gene-positive. Thirteen isolates had vanA(+)/vanB(+) genotype. Of these, ten exhibited a vanB phenotype and three had a vanA phenotype. Eight isolates with vanA(+)/vanB(-) genotype exhibited vanB phenotype. Six of these eight isolates belonged to the same pulsotype. All isolates were positive for gelE, esp, and EfaA( fm ) genes. Five were CylA-positive and 24 had the hyl genes. Of the eight isolates harboring a combination of gelE, esp, EfaA( fm ), and hyl genes, five showed vanB phenotype-vanA genotype incongruence. This is the first report of vanB phenotype-vanA genotype incongruent E. faecium in the Middle East region. Molecular typing indicates clonal spread and high occurrence of virulence genes, especially esp genes, associated with epidemic clones.

Bacteriocinogenic and virulence potential of Enterococcus isolates obtained from raw milk and cheese

To provide molecular and phenotypical characterization of Enterococcus isolates obtained from raw milk and cheese, regarding their bacteriocinogenic and virulence activity. Forty-three bacteriocinogenic enterococci isolates were identified by 16s rDNA, fingerprinted by RAPD-PCR analysis and tested by PCR for the presence of genes for lantibiotics (lanM, lanB and lanC) and enterocins (entA, entB, entP, entL50AB and entAS48) and by phenotypical methods for bacteriocin production and inhibitory spectrum. Also, the virulence of the isolates was evaluated by PCR for genes gelE, hyl, asa1, esp, cylA, efaA, ace, vanA, vanB, hdc1, hdc2, tdc and odc and by phenotypical tests for gelatinase, lipase, DNAse and α- and β-haemolysis. Most isolates (93·0%) harboured at least one lantibiotic or enterocin gene and were positive for several tested virulence genes, mainly asa1 (100%), gelE (93·0%) and efaA (83.7%). 53.5% of the isolates presented β-haemolysis [corrected]. Enterococcus spp. isolates presented an interesting potential application for food preservation because of bacteriocin production; however, virulence-related genes were identified in all RAPD profiles. The study demonstrated the contradictory characteristics of the tested Enterococcus isolates: they presented a good potential for application in food biopreservation but contained several virulence factors.

Genes de virulencia y bacteriocinas en cepas de Enterococcus faecalis aisladas desde diferentes muestras clínicas en la Región del Maule, Chile

The presence of virulence genes (VG) and bacteriocins from different clinical samples was studied in Enterococcus faecalis isolated from urinary tract infections (UTI), bacteremia and endodontitis and was correlated with haemolysin and gelatinase activity. We evaluated the presence of VG by PCR in 150 strains of E. faecalis including cylA, aggA, efaA, eep, gelE, esp, as-48, bac31, entL50A/B, entA, entP, entB, enlA andentl071. Haemolysin and gelatinase activity was studied. gelE and cylA genes expressed hemolysin and gelatinase, respectively. This activity was observed in some strains of bacteremia, UTI and endodontitis. The highest number of VG was detected in bacteremic strains, being aggA and entA genes the most frequent. efaA, esp, entA, entL50A/B were associated with their clinical origin (p < 0.05). The most common genetic profile was aggA-eep-enlA-entL50A/B. E. faecalis from UTI, bacteremia and endodontitis presented different gene combinations. Some of the genes studied were related to their clinical origin. The results obtained in this study are similar to those reported in other countries.

Occurrence of Virulence Determinants in Fecal Enterococcus faecalis Isolated from Pigs and Chickens in Korea

Forty-one Enterococcus faecalis (E. faecalis) isolates from feces of pigs and chickens in Korea were screened for the presence of virulence factors. Gelatinase activity (85.4%, 35/41) was the more commonly observed phenotype of virulence in E. faecalis, compared with hemolytic activity (12.2%, 5/41). Thirty-one of 35 (88.6%) gelatinase-positive E. faecalis isolates harbored the gelE and fsrABC genes. A gene encoding for the enterococcal surface protein (Esp) was detected in 24.4% (10/41) of the isolates. All betahemolysin- producing isolates harbored the esp gene.