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PubMedDate not supplied

Targeted sampling protocol as prelude to bacterial source tracking with Enterococcus faecalis.

Recent studies suggest that host origin databases for bacterial source tracking (BST) must contain a large number of isolates because bacterial subspecies change with geography and time. A new targeted sampling protocol was developed as a prelude to BST to minimize these changes. The research was conducted on the Sapelo River, a tidal river on the Georgia coast. A general sampling of the river showed fecal enterococcal numbers ranging from <10 (below the limit of detection) to 990 colony-forming units (CFU) per 100 mL. Locations with high enterococcal numbers were combined with local knowledge to determine targeted sampling sites. Fecal enterococcal numbers around one site ranged from <10 to 24,000 CFU per 100 mL. Bacterial source tracking was conducted to determine if a wastewater treatment facility at the site was responsible for this contamination. The fecal indicator bacterium was Enterococcus faecalis. Ribotyping, automated with a RiboPrinter (DuPont Qualicon, Wilmington, DE), was the BST method. Thirty-seven ribotypes were observed among 83 Ent. faecalis isolates obtained from the Sapelo River and the wastewater lagoon. Sixteen ribotypes were associated with either the river or the lagoon, and only five ribotypes (14%) were shared. Nevertheless, these five ribotypes represented 39 of the 83 Ent. faecalis isolates, almost a majority (47%). These results suggest that the fecal contamination in the river came from the wastewater treatment facility. As a prelude to BST, targeted sampling minimized subspecies changes with geography and time, and eliminated the need for a permanent host origin database by restricting BST to a small geographic area and requiring sampling to be completed in one day.

Animals↗
PubMed1995

Dosage of Tn916 circular intermediates in Enterococcus faecalis.

Upon excision, conjugative transposon Tn916 forms a nonreplicating circular intermediate (CI), which is essential both for transposition and conjugal transfer. In this work we developed an assay to quantify the circular forms of Tn916. By this method we defined a new measurable trait of Tn916-carrying strains: the "CI copy number." CI dosage was performed by nested PCR (with primers designed on Tn916 termini) in a limiting dilution assay, where Poisson statistics were used to calculate the number of PCR amplification targets from the proportion of the negative endpoints. The number of CI was normalized to the number of bacterial chromosomes. This method enabled us to study the relationship between CI copy number, presence of tetracycline (the resistance marker of Tn916) in the culture medium, and conjugation frequency. Three isogenic strains of Enterococcus faecalis OG1 with Tn916 inserted at different sites on the chromosome were investigated for CI content. CI copy number varied depending on the strain, ranging between 7.8 and 610 copies per 10(6) chromosomes. Growth in liquid media containing tetracycline provoked an important increase both in CI copy number and conjugation frequency. This effect was more marked in low-frequency donors. While cell-cell contact during filter mating did not produce an increase in CI copy number, Tn916 conjugation frequency was found to be dependent on CI copy number in donor cells. The dose-response curve showed a linear relationship with a slope of 0.74, for the entire range of conjugation frequencies tested (from 5.1 x 10(-8) to 2.8 x 10(-6) transconjugants per donor.

Bacterial Adhesion↗
PubMed1999

In-vitro activity of moxifloxacin against fluoroquinolone-resistant strains of aerobic gram-negative bacilli and Enterococcus faecalis.

MICs of the new fluoroquinolone, moxifloxacin, and those of ciprofloxacin, ofloxacin and sparfloxacin for 19 genetically characterized fluoroquinolone-resistant strains were determined by the agar dilution method. The MICs of moxifloxacin for Escherichia isolates with one mutation in gyrA (corresponding to Ser83-->Leu or Asp87-->Gly substitution) were 0.25-0.5 mg/L, while those of ciprofloxacin, ofloxacin and sparfloxacin were 0.06-0.25, 1 and 0.12-0.5 mg/L, respectively. These values were four- to 16-fold higher than those of the same antibiotics for the wild-type strain, E. coli KL16. Similar results were observed with clinical isolates of Salmonella spp. harbouring one mutation in gyrA leading to the substitution of Ser83 by Phe or Tyr. In the presence of two mutations in the E. coli gyrA gene, the MICs of moxifloxacin ciprofloxacin, ofloxacin and sparfloxacin were 2, 0.5, 4 and 1 mg/L, respectively; these were 32 times higher than the MICs of these agents for E. coli KL16. The MICs of the four quinolones for triple mutants with two mutations in gyrA and one in parC were even higher, i.e. 8, 8, 16 and 8-16 mg/L, respectively. The MICs of moxifloxacin for Campylobacter coli and Campylobacter jejuni strains with a gyrA mutation leading to Thr86-->Ile substitution ranged from 1 to 2 mg/L, while the MICs of ciprofloxacin, ofloxacin and sparfloxacin were 16-32 mg/L, 8-16 and 4-8 mg/L, respectively. For high-level ciprofloxacin-resistant (MICs of 32 mg/L) clinical isolates of Enterococcus faecalis with one substitution at position 83 in GyrA (E. coli coordinates), the MICs of moxifloxacin, ofloxacin and sparfloxacin were 8-16, > or = 128 and 32 mg/L respectively. In conclusion, moxifloxacin and other fluoroquinolones exhibit cross-resistance against aerobic gram-negative bacilli and enterococci. The in-vitro activity of moxifloxacin was greater than that of ofloxacin and slightly less than that of ciprofloxacin and sparfloxacin against Enterobacteriaceae, but greater than those of the three other compounds tested against Campylobacter spp and E. faecalis.

Anti-Infective Agents↗
PubMed2006

Characterization of antimicrobial substances produced by Enterococcus faecalis MRR 10-3, isolated from the uropygial gland of the hoopoe (Upupa epops).

The uropygial gland (preen gland) is a holocrine secretory gland situated at the base of the tail in birds which produces a hydrophobic fatty secretion. In certain birds, such as the hoopoe, Upupa epops, the composition of this secretion is influenced by both seasonal and sexual factors, becoming darker and more malodorous in females and in their nestlings during the nesting phase. The secretion is spread throughout the plumage when the bird preens itself, leaving its feathers flexible and waterproof. It is also thought to play a role in defending the bird against predators and parasites. We have isolated from the uropygial secretion of a nestling a bacterium that grows in monospecific culture which we have identified unambiguously by phenotypic and genotypic means as Enterococcus faecalis. The strain in question produces antibacterial substances that are active against all gram-positive bacteria assayed and also against some gram-negative strains. Its peptide nature identifies it as a bacteriocin within the group known as enterocins. Two peptides were purified to homogeneity (MR10A and MR10B), and matrix-assisted laser desorption ionization-time of flight (mass spectrometry) analysis showed masses of 5201.58 and 5207.7 Da, respectively. Amino acid sequencing of both peptides revealed high similarity with enterocin L50A and L50B (L. M. Cintas, P. Casaus, H. Holo, P. E. Hernández, I. F. Nes, and L. S. Håvarstein, J. Bacteriol. 180:1988-1994, 1998). PCR amplification of total DNA from strain MRR10-3 with primers for the L50A/B structural genes and sequencing of the amplified fragment revealed almost identical sequences, except for a single conservative change in residue 38 (Glu-->Asp) in MR10A and two changes in residues 9 (Thr-->Ala) and 15 (Leu-->Phe) in MR10B. This is the first time that the production of bacteriocins by a bacterium isolated from the uropygial gland has been described. The production of these broad-spectrum antibacterial substances by an enterococcal strain living in the uropygial gland may be important to the hygiene of the nest and thus to the health of the eggs and chicks.

Amino Acid Sequence↗
PubMed1999

An Escherichia coli-Enterococcus faecalis shuttle vector as a tool for the construction of a group B Streptococcus heterologous mutant expressing the beta antigen (Bac) of the C protein complex.

Group B streptococci (GBS) represent a very important group of human pathogens. So far little is known about the mechanisms by which these bacteria can cause disease and the bacterial factors involved. One putative virulence factor is the beta antigen of the C protein complex (Bac), which can bind to the Fc region of human IgA. Its binding function might represent an important virulence mechanism. However, the genetic manipulation of this group of bacteria, necessary to prove involvement of bacterial factors in pathogenesis, is still in its infancy. We therefore tested the pAM401 vector system for its suitability in the construction of a heterologous expression mutant using the Bac protein as a model antigen. The bac gene, including its own promoter, was cloned into the Escherichia coli-Enterococcus faecalis shuttle vector pAM401 and was stably maintained extrachromosomally in the bac-deficient GBS strain 335. Expression of Bac was assessed by extracting the protein from transformed 335(pPJTU1) cells, negative controls (335 wild-type, 335(pAM401)) and other Bac-expressing GBS strains (A909, LA239). Blots of the extracted proteins probed with IgA, polyclonal sera and a monoclonal antibody raised against Bac clearly revealed expression of the 130-kDa protein in the transformed GBS 335(pPJTU1) cells. The correct processing and surface anchoring of the expressed Bac was demonstrated by binding of (125)I-labelled IgA to whole cells. Strain 335(pPJTU1) bound 12 times as much IgA compared to the parental strain LA239 and the GBS 335 negative controls, and a total of 25% compared to the high-level-expressing strain A909. Our studies show that the pAM401 shuttle vector can be used for stable heterologous expression of surface proteins in GBS. Our strategy is also of major importance for the complementation of deletion mutants in GBS and other Gram-positive human pathogens to fulfill Koch's postulates. The Bac mutant constructed in this study, 335(pPJTU1), can be used in animal models to assess the importance of Bac in GBS pathogenesis.

Antigens, Bacterial↗
PubMed2001

Fractional maximal effect method for in vitro synergy between amoxicillin and ceftriaxone and between vancomycin and ceftriaxone against Enterococcus faecalis and penicillin-resistant Streptococcus pneumoniae.

In the present study we assessed the use of a new in vitro testing method and graphical representation of the results to investigate the potential effectiveness of combinations of amoxicillin (AMZ) plus ceftriaxone (CRO) and of CRO plus vancomycin (VAN) against strains of Streptococcus pneumoniae highly resistant to penicillin and cephalosporins (PRP strains). We used the fractional maximal effect (FME) method of time-kill curves to calculate adequate concentrations of the drugs to be tested rather than relying on arbitrary choices. The concentrations obtained, each of which corresponded to a fraction of the maximal effect, were tested alone and in combination with the bacterial strains in a broth medium. Synergy was defined as a ratio of observed effect/theoretical effect, called FME, of greater than 1, additivity was defined as an FME equal to 1, and antagonism was defined as an observed effect lower than the best effect of one of the antibiotics used alone. The area between antagonism and additivity is the indifference zone. The well-known synergy between amoxicillin and gentamicin against a reference strain of Enterococcus faecalis was confirmed, with a best FME equal to 1.07. Two strains of PRP, strains PRP-1 and PRP-2, were studied. The MICs for PRP-1 and PRP-2 were as follows: penicillin, 4 and 16 microg/ml, respectively; AMZ, 2 and 8 microg/ml, respectively, CRO, 1 and 4 microg/ml, respectively; and VAN, 0.5 and 0.25 microg/ml, respectively. For PRP-1 the best FME for the combination AMZ-CRO was 1.22 with drug concentrations of 1.68 mg/liter for AMZ and 0.17 mg/liter for CRO; the best FME for the combination VAN-CRO was 1.75 with VAN at 0.57 mg/liter and CRO at 0.17 mg/liter. For PRP-2 the best FME obtained for the combination AMZ-CRO was 1.05 with drug concentrations of 11.28 mg/liter for AMZ and 0.64 mg/liter for CRO; the best FME obtained for the combination VAN-CRO was 1.35 with VAN at 0.25 mg/liter and CRO at 1.49 mg/liter. These results demonstrated the synergy of both combinations, AMZ-CRO and VAN-CRO, against PRP strains at drug concentrations achievable in humans. Consequently, either of the combinations can be proposed for use for the treatment of PRP infections.

Amoxicillin↗
PubMed1993

Identification, characterization, and nucleotide sequence of a region of Enterococcus faecalis pheromone-responsive plasmid pAD1 capable of autonomous replication.

A 5-kbp region of pAD1, previously shown to be capable of supporting replication, copy control, and stable inheritance of the plasmid, was cloned into a replicon probe vector and subjected to transposon insertional mutagenesis. Transposon inserts identifying essential replication, copy control, and stability functions were isolated. Deletion of stability functions not essential for replication resulted in delimitation of a basic replicon. The complete DNA sequence of this approximately 3-kbp region and the precise positions of several transposon inserts were determined, and the phenotypic effects of the transposon inserts were correlated with the physical locations of individual determinants. The following three genes, apparently involved in plasmid maintenance, were identified; repA, which encodes a protein required for replication; repB, which encodes a protein involved in copy control; and repC, which may be involved in stable inheritance. In addition, two clusters of repeats composed of a consensus sequence, TAGTARRR, were identified, one located between the divergently transcribed repA and repB genes and another located downstream of repC. The region between repA and repB contained 25 repeats divided into two subregions of 13 and 12 repeats separated by 78 bp. The region located downstream of repC contained only three repeats but may be essential for plasmid replication, since deletion of this determinant resulted in loss of ability to replicate in Enterococcus faecalis. We hypothesize that the repeat units represent protein-binding sites required for assembly of the replisome and control of plasmid copy number. Another region of unrelated repeat units that may also be involved in replication is located within the repA gene. Possible mechanisms of action of these determinants are discussed.

Amino Acid Sequence↗
PubMedDate not supplied

Therapeutic effects of cefpirome (HR 810) on experimental mixed infections with Enterococcus faecalis and Escherichia coli in mice.

The therapeutic effects of cefpirome (HR 810), a new cephalosporin, on mixed infections induced in mice with Enterococcus faecalis HL1147 and Escherichia coli HL34 were compared with those of ampicillin (AMP), cefuzonam (CZON), and ceftazidime (CAZ). Cefpirome was more effective in protecting mice with systemic mixed infection (median effective dose, 52 mg/kg) than the other antibiotics (all more than 320 mg/kg). With increasing doses of cefpirome, the percentages of the animals having E. faecalis and E. coli bacteremia were decreased. CZON and CAZ reduced only E. coli, and AMP failed to reduce both strains. In the mice with urinary tract mixed infection, cefpirome and CZON (40 mg/kg x 5, s.c.) significantly decreased the cfu/g kidney (p less than 0.01 vs. nontreated control), while AMP and CAZ were active only against E. faecalis (p less than 0.05) and E. coli (p less than 0.01), respectively.

Ampicillin↗
PubMed1991

Comparative analysis of Enterococcus faecalis sex pheromone plasmids identifies a single homologous DNA region which codes for aggregation substance.

An analysis of the 11 known sex pheromone plasmids of Enterococcus faecalis was performed by DNA-DNA hybridization. Plasmids pAD1, pJH2, and pBEM10 turned out to be closely related, whereas pAM373 showed only weak homology with pAD1. A comparison of the hemolysin/bacteriocin determinants of pAD1, pJH2, and pOB1 revealed strong similarities at the DNA level. Our main finding was that one DNA region is conserved among all sex pheromone plasmids, with pAM373 again being an exception; for pAD1 this region was shown earlier to code for aggreagation substance. Detailed hybridization studies of the genes for this plasmid-coded adhesin, which is responsible for cell-cell contact during conjugative transfer via the so-called sex pheromone system of E. faecalis, support the idea of their common origin.

Adhesins, Escherichia coli↗
PubMed1991

Detection of penicillin-binding proteins immunologically related to penicillin-binding protein 5 of Enterococcus hirae ATCC 9790 in Enterococcus faecium and Enterococcus faecalis.

Penicillin-binding protein (PBP) 5 of Enterococcus hirae ATCC 9790 belongs to the class of the high-molecular mass, low-affinity PBPs which have been correlated with penicillin resistance in most Enterococcus species. Polyclonal antibodies were raised against PBP 5 and used to detect immunologically related membrane proteins in E. faecium and E. faecalis strains. Several strains of both species were found to have a membrane protein of similar molecular mass to E. hirae PBP 5 which reacted with the antibodies. Some E. faecium strains did not react with antibodies but their derivatives with increased penicillin minimal inhibitory concentrations did. In some E. faecalis strains the lack of a PBP 5-related protein was associated with failure to select stable penicillin-resistant derivatives.

Bacterial Proteins↗
PubMed1999

Determination of nucleotide sequence related to the plasmid replication region in Enterococcus faecalis and its application to a new shuttle vector.

The 5.1-kb plasmid pAMalpha1delta2, a derivative of the 9.6-kb plasmid pAMalpha1 which is harbored by Enterococcus faecalis ATCC 14508, has a region necessary for replication in E. faecalis. The nucleotide sequence related to the replication region in pAMalpha1delta2 was determined and found to contain an open reading frame of 720-bp encoding a replication protein. The sequence showed 54.5 and 48.5% homology to those encoding the RepAs of plasmids pLA103 from Lactobacillus acidophilus and pFA3 from Neisseria gonorrhoeae, respectively. A recombinant 5.8-kb plasmid, pEFX6, which can be used as a shuttle vector between Escherichia coli and some strains of E. faecalis, was constructed by combining the tetracycline resistance gene of pAMalpha1delta2 and the replication regions of pAMalpha1delta2 and pUC18 for E. faecalis and E. coli, respectively. This shuttle vector was successfully used to clone and express the gelatinase gene from E. faecalis subsp. zymogenes IFO 3989 in E. faecalis C57, a strain showing no gelatinase activity.

Journal Article↗
PubMed1997

Conjugative transfer of tet(S) between strains of Enterococcus faecalis is associated with the exchange of large fragments of chromosomal DNA.

The tetracycline resistance determinant tet(S) was first detected in antibiotic multiresistant Listeria monocytogenes BM4210 and subsequently in strains of Enterococcus faecalis. Transfer of tet(S) from clinical isolate E. faecalis BM4242 to E. faecalis strains JH2-2 and OG1RF was found to require the presence in the donor strain of the 55 kb conjugative plasmid pIP825. Comparison of restriction endonuclease generated maps of the donor, the two recipients, and of four transconjugants indicated that transfer of tet(S) (i) was from chromosome to chromosome, (ii) resulted in the acquisition of an approximately 40 kb element in the same chromosomal region and (iii) was associated with the exchange of large chromosomal fragments. Similar observations were made following conjugal transfer of tet(S) from four other E. faecalis clinical isolates.

Chromosome Mapping↗
PubMed1986

Potent antagonism of Escherichia coli, Bacteroides ovatus, Fusobacterium varium, and Enterococcus faecalis, alone or in combination, for enteropathogens in anaerobic continuous flow cultures.

Interactions between representative strains of four predominant resident bacteria of the human colon, Escherichia coli, Enterococcus faecalis, Bacteroides ovatus, and Fusobacterium varium, and strains of seven enteropathogens, Yersinia enterocolitica, Shigella flexneri, Salmonella typhimurium, Vibrio parahaemolyticus, V. cholerae serogroup non O1, Staphylococcus aureus, and Clostridium perfringens, were examined in studies with an anaerobic continuous flow culture system and medium resembling the content of the mouse caecum (MCM). Potent unilateral antagonism attributable to synergic activities of the resident bacteria against the enteropathogens was evident. The four resident bacteria persisted at levels of c. 10(6) cfu/ml or more in single and in any mixed cultures of the resident species. The seven enteropathogens also persisted in single cultures. In contrast, Y. enterocolitica was excluded in several days in mixed cultures with each of the four resident bacteria. Sh. Flexneri and Staph. aureus were excluded in the presence of E. coli alone. C. perfringens, V. parahaemolyticus and V. cholerae serogroup non O1 were excluded in the presence of E. coli with B. ovatus and, in some cases, with additional species. S. typhimurium was the most resistant; only c. 10(2)-fold reduction of the population level was observed in mixed culture with all four of the resident species. When the amounts of some components in the medium, such as peptone and yeast extract, were increased, C. perfringens grew and persisted even in the presence of the four resident bacteria. Sh. flexneri, in contrast decreased steadily, even in enriched media.

Anaerobiosis↗
PubMed1991

[A case of mediastinal abscess due to Enterococcus faecalis accompanied with superior vena cava syndrome].

Superior vena cava (SVC) syndrome caused by benign diseases is rare. We reported a case of mediastinal abscess due to Enterococcus faecalis (E. faecalis) accompanied with SVC syndrome and reviewed the literature on this particular condition. A 38-year-old female with swelling of the neck and dilatation of cervical vein was admitted to our hospital, being diagnosed as having a SVC syndrome. Chest roentgenogram revealed an enlargement of the right upper mediastinum and a massive infiltration in the right upper lung field. CT scan demonstrated a mass with central necrosis occupying the right upper mediastinum and stenosis of superior vena cava. Further conformation of the stenosis of vena cava was made by means of venography. E. faecalis was recovered from the pus aspirated from the mediastinal abscess, and a definitive diagnosis of SVC syndrome caused by mediastinal abscess due to E. faecalis was made. There has been no report, to our knowledge, on mediastinal abscess evolving SVC syndrome in which E. faecalis was identified as a causative organism. The present case indicates that a benign disease such as lung abscess should be considered to be a possible cause of SVC syndrome in addition to other frequent malignant diseases.

Abscess↗
PubMed1990

Genetic analysis of the pAD1 hemolysin/bacteriocin determinant in Enterococcus faecalis: Tn917 insertional mutagenesis and cloning.

Thirty-seven nonhemolytic/nonbacteriocinogenic mutations in Enterococcus (Streptococcus) faecalis plasmid pAD1 were generated by Tn917 insertion. All were found to belong to one of two complementation classes. Each class of mutants secreted either hemolysin/bacteriocin (Hly/Bac) component A or L into the culture medium. DNA encoding Hly/Bac was cloned in Escherichia coli in which both components of the hemolysin were expressed individually and collectively. The region encoding components A and L was further defined by deletion analysis and physically mapped. A total of approximately 8.4 kilobases of pAD1 DNA were observed to be required for hemolysin expression. Hly/Bac activity of the wild-type and the inactive L substance was observed to be heat stable. Active Hly/Bac resulting from incubating separately secreted components A and L was also found to be heat stable. The results indicate that component A activates component L and that activated component L possesses the Hly/Bac activity. Component A was also observed to be associated with host immunity to the Hly/Bac.

Bacteriocins↗
PubMed2006

Comparison of testing methods for detection of decreased linezolid susceptibility due to G2576T mutation of the 23S rRNA gene in Enterococcus faecium and Enterococcus faecalis.

E-test, Vitek 2, MicroScan, agar dilution, and disk diffusion were compared for detection of decreased linezolid susceptibility due to 23S rRNA gene G2576T mutation among 32 clinical Enterococcus strains initially reported as intermediate or resistant by E-test alone or Vitek 2 confirmed by E-test. Agar and broth dilution methods were in concordance with PCR detection of the mutation, and disk diffusion was somewhat less sensitive but equally specific.

Acetamides↗
PubMed1991

Mannitol-specific phosphoenolpyruvate-dependent phosphotransferase system of Enterococcus faecalis: molecular cloning and nucleotide sequences of the enzyme IIIMtl gene and the mannitol-1-phosphate dehydrogenase gene, expression in Escherichia coli, and comparison of the gene products with similar enzymes.

Enzyme IIIMtl is part of the mannitol phosphotransferase system of Enterococcus faecalis. It is phosphorylated in a reaction sequence requiring enzyme I and heat-stable phosphocarrier protein (HPr). The phospho group is transferred from enzyme IIIMtl to enzyme IIMtl, which then catalyzes the uptake and concomitant phosphorylation of mannitol. The internalized mannitol-1-phosphate is oxidized to fructose-6-phosphate by mannitol-1-phosphate dehydrogenase. In this report we describe the cloning of the mtlF and mtlD genes, encoding enzyme IIIMtl and mannitol-1-phosphate dehydrogenase of E. faecalis, by a complementation system designed for cloning of gram-positive phosphotransferase system genes. The complete nucleotide sequences of mtlF, mtlD, and flanking regions were determined. From the gene sequences, the primary translation products are deduced to consist of 145 amino acids (enzyme IIIMtl) and 374 amino acids (mannitol-1-phosphate dehydrogenase). Amino acid sequence comparison confirmed a 41% similarity of E. faecalis enzyme IIIMtl to the hydrophilic enzyme IIIMtl-like portion of enzyme IIMtl of Escherichia coli and 45% similarity to enzyme IIIMtl of Staphylococcus carnosus. The putative N-terminal NAD+ binding domain of mannitol-1-phosphate dehydrogenase of E. faecalis shows a high degree of similarity with the N terminus of E. coli mannitol-1-phosphate dehydrogenase (T. Davis, M. Yamada, M. Elgort, and M. H. Saier, Jr., Mol. Microbiol. 2:405-412, 1988) and the N-terminal part of the translation product of S. carnosus mtlD, which was also determined in this study. There is 40% similarity between the dehydrogenases of E. faecalis and E. coli over the whole length of the enzymes. The organization of mannitol-specific genes in E. faecalis seems to be similar to the organization in S. carnosus. The open reading frame for enzyme IIIMtl E. faecalis is followed by a stem-loop structure, analogous to a typical Rho-independent terminator. We conclude that the mannitol-specific genes are organized in an operon and that the gene order is mtlA orfX mtlF mtlD.

Amino Acid Sequence↗