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PubMed2006

[Bacteraemia due to Leuconostoc spp. in a patient without immunological disorders].

Leuconostoc spp are gram-positive coccobacilli, catalase and oxidase negative, vancomycin resistant. Causes of infection have been reported previously but it has not been described confirmed bacteremia due to Leuconostoc spp in patient without other immunological disorders. We describe a case of bacteremia in a 64-years-old man with a prosthetic valve 7 months before to begin fever of unknown origin. We confirmed bacteremia due Leuconostoc spp and the treatment with respective antibiotics permits the cure. Leuconostoc spp should be considered as a potential cause of bacteraemia, but we would be observant to the bacteremias due vancomycin resistant germs, because in most cases the laboratory do not find the sensitivity to this antibiotic.

Bacteremia↗
PubMed2005

[Case report: two Leuconostoc bacteremia cases].

Leuconostoc species, which are the members of Streptococcaceae family, have recently been recognized as potential pathogens. They usually cause infections in patients with underlying disease, with venous catheters or previously treated with vancomycin. In this report, we have presented two cases of Leuconostoc bacteremia. The first case was a 42 years old male patient who was diagnosed to have colon adenocarcinoma. He had undergone colon, stomach and distal pancreas resection operation and had given chemotherapy. Blood and catheter cultures yielded methicillin-resistant Staphylococcus aureus. Blood cultures were repeated since teicoplanin therapy had failed, and Gram positive cocci resistant to vancomycin were isolated. The other case was a 26 years old male patient who had undergone a shunt operation because of pineal lesion and hydrocephaly. He had given ampirical vancomycin therapy since he had post-operative high fever, however the therapy had failed. The catheter culture yielded Gram positive cocci resistant to vancomycin. Both isolates were identified as Leuconostoc spp. with API 20 strep identification kit (Bio Merieux), and both of them were found sensitive to penicillin, ampicillin, clindamycin, gentamicin and chloramphenicol, while they were resistant to teicoplanin and vancomycin. The patients were successfully treated with clindamycin. It is concluded that, Leuconostoc spp. should be considered when vancomycin-resistant organisms resembling streptococci are isolated from blood cultures.

Adult↗
PubMed2005

Genetic diversity among Lactococcus sp. and Leuconostoc sp. strains using PCR-RFLP of insertion sequences ISS1-type, IS904, and IS982.

PCR-RFLP analysis of commonly occurring insertion sequences ISS1-type, IS904 and IS982 in Lactococcus sp. and Leuconostoc sp. was used for the genetic differentiation of 17 strains of lactic acid bacteria. ISS1-type and IS982 were found in all analysed strains while IS904 was present exclusively in strains belonging to Lactococcus sp. Amplification of ISS1-type IS sequences resulted in formation of about 820 bp long amplicons, except of strains Lactococcus lactis ssp. lactis E and Leuconostoc lactis R where extra DNA bands about 370 bp long were observed. Similarly for strains of Leuconostoc lactis M and N, additional DNA bands about 280 bp long were present. TaqI digestion of ISS1-type amplicons revealed that all analysed sequences belonged to the restriction type (ii) or (iii) for which major restriction products were 543 and 147 bp long. Amplification of IS904 from all strains of Lactococcus sp. generated amplicons about 1260 bp long. In three strains of Leuconostoc sp. M, N and R, shorter amplicons about 880 bp were observed whereas strains O and P did not contained IS904. Amplification of IS982 resulted in formation of amplicons about 1000 bp long and no extra bands were observed for all tested strains. TaqI digestion of amplification products showed that for strains C, I and F, G, H, belonging to Lactococcus sp. smaller DNA bands were visible suggesting that they contain two different types of IS982.

DNA Transposable Elements↗
PubMed1997

Leuconostoc bacteremia after liver transplantation: another cause of vancomycin resistant gram-positive infection.

Leuconostoc sp. are gram-positive bacteria intrinsically resistant to vancomycin, which can be confused with streptococci based on routine microbiological-characteristics. Infections secondary to Leuconostoc are uncommon, and usually affect patients with underlying diseases, prior use of vancomycin and those with central lines. The most common clinical presentation is fever secondary to a central line infection. We report the first case of Leuconostoc infection in a solid organ transplant recipient. The patient developed Leuconostoc bacteremia secondary to peritonitis, 60 d after undergoing liver transplantation. He was treated with clindamycin, gentamicin and underwent surgical debridement, but succumbed to other complications.

Adult↗
PubMed1991

Citrate Fermentation by Lactococcus and Leuconostoc spp.

Citrate and lactose fermentation are subject to the same metabolic regulation. In both processes, pyruvate is the key intermediate. Lactococcus lactis subsp. lactis biovar diacetylactis homofermentatively converted pyruvate to lactate at high dilution (growth) rates, low pH, and high lactose concentrations. Mixed-acid fermentation with formate, ethanol, and acetate as products was observed under conditions of lactose limitation in continuous culture at pH values above 6.0. An acetoin/butanediol fermentation with alpha-acetolactate as an intermediate was found upon mild aeration in continuous culture and under conditions of excess pyruvate production from citrate. Leuconostoc spp. showed a limited metabolic flexibility. A typical heterofermentative conversion of lactose was observed under all conditions in both continuous and batch cultures. The pyruvate produced from either lactose or citrate was converted to d-lactate. Citrate utilization was pH dependent in both L. lactis and Leuconostoc spp., with maximum rates observed between pH 5.5 and 6.0. The maximum specific growth rate was slightly stimulated by citrate, in L. lactis and greatly stimulated by citrate in Leuconostoc spp., and the conversion of citrate resulted in increased growth yields on lactose for both L. lactis and Leuconostoc spp. This indicates that energy is conserved during the metabolism of citrate.

Journal Article↗
PubMed1997

Bacteremia caused by Leuconostoc cremoris in a patient with severe burn injuries.

A case of Leuconostoc cremoris bacteremia in a patient with burn wounds over 45% of the body surface is presented. Leuconostoc bacteremia has not previously been reported in burn patients. The predisposing factors in this case were severe burn wounds resulting in immunocompromise, presence of both intravenous and enteral feeding catheters, several surgical interventions and previous treatment with imipenem plus amikacin. The patient was successfully treated with ampicillin 2 g l.v. every 6 hours for 21 days. Infection with Leuconostoc should be suspected when vancomycin-resistant organisms resembling streptococci are isolated.

Adult↗
PubMed1991

Leuconostoc species as a cause of bacteremia: two case reports and a literature review.

Two new cases of significant bacteremia caused by Leuconostoc spp. are reported and five others described in the literature are reviewed. Four of the seven patients were under one year old and presented with prolonged diarrhea related to gastrointestinal disorders. The remaining three patients were over 50 years of age and being treated in intensive care units. Six patients had nosocomially acquired catheter-related bacteremia. Leuconostoc spp. are naturally resistant to vancomycin, and five patients had received this antibiotic for prior bacteremia caused by methicillin-resistant staphylococci. The majority of patients presented with fever without severe complications. Penicillin is the treatment of choice and there is no report of any death directly attributable to infection by these microorganisms. Infection with Leuconostoc spp. should be suspected if "vancomycin-resistant streptococci" are isolated from the blood, and recorded as a potential cause of bacteremia in patients with indwelling intravenous catheters.

Age Factors↗
PubMed1992

Classification of ropy slime-producing lactic acid bacteria based on DNA-DNA homology, and identification of Lactobacillus sake and Leuconostoc amelibiosum as dominant spoilage organisms in meat products.

The classification of lactic acid bacteria able to cause ropy slime on vacuum-packed cooked meat products was carried out based on DNA-DNA homology. The ropy slime-producing lactobacilli were identified as strains of Lactobacillus sake and the ropy slime-producing leuconostocs, such as Leuconostoc amelibiosum and Leuconostoc mesenteroides.

DNA, Bacterial↗
PubMed1990

A phylogenetic analysis of the genus Leuconostoc based on reverse transcriptase sequencing of 16 S rRNA.

The phylogenetic interrelationships of members of the genus Leuconostoc and some heterofermentative lactobacilli, which phenotypically resemble leuconostocs, were investigated by comparative analysis of their 16 S rRNA sequences. The six species, Leuconostoc mesenteroides, Leu. carnosum, Leu. citreum, Leu. gelidum, Leu. lactis and Leu. pseudomesenteroides exhibited a high degree of sequence similarity with each other and formed a phylogenetically coherent group, quite separate from all other lactic acid bacteria investigated. The species Leu. paramesenteroides was found to be phylogenetically distinct from the Leu. mesenteroides group of species and formed a natural grouping with the heterofermentative lactobacilli, Lb. confusus, Lb. kandleri, Lb. minor and Lb. viridescens. The rRNA sequence of the acidophilic species, Leu. oenos, displayed exceptionally low levels of homology with all of the other taxa examined. The 16 S sequence of Leu. oenos showed major nucleotide differences in relatively highly conserved positions of the molecule indicating this species is phylogenetically distinct and warrants a separate genus.

Base Sequence↗
PubMed2006

Characterization of pFMBL1, a small cryptic plasmid isolated from Leuconostoc mesenteroides SY2.

A 4661bp cryptic plasmid, pFMBL1, was isolated from Leuconostoc mesenteroides SY2, an isolate from Kimchi, and characterized. Nucleotide sequence analysis revealed two open reading frames, orf1 and orf2. orf2 was 453bp in size and its translation product had 58% identity with a putative protein possibly involved in the replication of pTXL1, a cryptic plasmid from L. mesenteroides ssp. mesenteroides Y110. RNA transcript from orf2 was detected but not from orf1 or intergenic region. Minimum 3.5kb fragment encompassing orf1 and orf2 was required for the replication of pFMBL1 and employed for the construction of Escherichia coli-Leuconostoc shuttle vector, pSJ33E. L. mesenteroides SY1 (another Kimchi isolate), Leuconostoc ssp., and Lactobacillus brevis were successfully transformed with pSJ33E, and the transformation efficiencies were ranged between 1.1x10(1) and 4x10(5)transformants/microg DNA. No single-stranded DNA intermediate was detected from L. mesenteroides SY1 cells harboring pSJ33E, indicating that pFMBL1 probably replicated via theta-type mechanism. pSJ33E was stably maintained in L. mesenteroides SY1 in the absence of erythromycin (Em, 5 microg/ml) and after 1 month of daily subculturing in MRS broth without selective pressure, three percent of cells still retained pSJ33E.

Base Pairing↗
PubMed2000

Valine transport and biodiversity of Leuconostoc wild strains from French raw milk cheeses.

The rate of L-valine transport in whole cells of Leuconostoc was at the maximum at 30 degrees C, pH 6.0 in the presence of an energy source. Transport was inhibited by 40-55%, in the presence of the ionophores (valinomycin, nigericin or monensin), and uncouplers (carbonyl cyanide-m-chloro-phenylhydrazone or 2,4-dinitrophenol) confirming the previously described delta p-driven branched-chain amino acid transport system described in cytoplasmic membranes (Winters et al., 1991, Appl. Environ. Microbiol., 57, 3350-3354). Sulfhydryl group reagents (p-chloro-mercuribenzoate, iodoacetate and N-ethyl maleimide) all inhibited valine transport by 60-70%, indicating that valine is actively transported at high valine concentration. Three kinetically distinguishable transport systems were identified for each strain using whole cells, confirming results obtained with membranes. L-valine transport Kt and Vmax could be an additional tool to estimate the biodiversity of 18 Leuconostoc strains belonging to the dominant flora of French raw milk cheeses. Kt values varied from 20 to 510 nmol/l for the very high affinity system, from 26 to 427 pmol/l for the high affinity system and from 0.65 to 4.40 mmol/l for the low affinity system. No correlation existed between valine transport rates and a particular strain's ability to acidify milk or complex media, suggesting that valine transport is not a growth-limiting function in species of the genus Leuconostoc.

Biological Transport, Active↗
PubMed2001

Characterization of dextran-producing Leuconostoc strains.

Leuconostoc strains were characterized according to their antibiotic susceptibilities, carbohydrate fermentation profiles, sucrase activity patterns and plasmid content. All the strains tested were resistant to the antibiotics sulphathiazole, trimethoprim and vancomycin, and could be separated into two groups based on whether or not they could ferment melibiose and raffinose. Six Leuconostoc strains possessed plasmids and many produced unique sucrase activity patterns in polyacrylamide gels. These data will aid in distinguishing among physiologically similar dextran-producing leuconostocs, frequently used in research and industry.

Anti-Bacterial Agents↗
PubMed1994

Nucleotide sequence and structural organization of the small, broad-host-range plasmid pCI411 from Leuconostoc lactis 533.

The nucleotide sequence of the Leuconostoc lactis 533 cryptic plasmid pCI411 (2926 bp) was determined. Analysis revealed the presence of three open reading frames (ORFs). ORF 1 was capable of encoding a 24.9 kDa peptide which shared homology with the replication initiation protein (RepB) from a number of Gram-positive rolling circle plasmids. ORF 2 could encode a peptide of 6.6 kDa which was homologous to the RepC protein of the lactococcal plasmid pWV01. A function could not be assigned to ORF 3, which was capable of encoding a 12.1 kDa peptide. Transcription-translation analysis indicated the presence of three peptides of the predicted molecular masses. A putative double strand origin of replication (DSO) was identified which showed strong similarity with the DSO of a number of Gram-positive plasmids including pE194 from Staphylococcus. Structural analysis identified a number of direct and indirect repeats in addition to putative recombination-specific sites (RSA and RSB) in the non-coding region of pCI411. The observed characteristics suggest that this plasmid replicates using the rolling circle mechanism. pCI411, which could be introduced into Leuconostoc, Lactococcus, Streptococcus, Lactobacillus and Bacillus is the first plasmid from the genus Leuconostoc to be characterized in such detail.

Amino Acid Sequence↗
PubMed2003

Molecular characterization and expression analysis of the dextransucrase DsrD of Leuconostoc mesenteroides Lcc4 in homologous and heterologous Lactococcus lactis cultures.

The gene encoding the dextransucrase DsrD from the industrial strain Leuconostoc mesenteroides Lcc4 was isolated by PCR using degenerate primers recognizing conserved regions present in other dextransucrase-encoding genes from Leuconostoc spp. and Southern blot analyses on total genomic DNA. N-terminal sequence analysis of the active protein recovered in the culture showed that the secreted protein of 165 kDa is devoid of a 42 aa prepeptide which is removed post-translationally, most likely by signal peptidase cleavage. Primer extension and Northern blot analysis identified a monocistronic dsrD mRNA with two transcription initiation sites. Expression of the dextransucrase DsrD was investigated in pH-controlled fed-batch cultures via Northern blot analysis and enzyme activity measurement during the experiments. Sucrose levels of 20 g l(-1) were shown to induce the DsrD biosynthesis around 10-fold. The combination of pH-controlled fed-batch fermentation and Northern analysis clearly showed that dsrD expression was related to the growth of the bacteria. dsrD was transferred to and expressed in Lactococcus lactis MG1363. Controlled fed-batch cultures revealed that active dextransucrase was produced and secreted by the recombinant L. lactis strain. The expression was independent of sucrose levels. These results show that dextransucrase can be efficiently expressed and secreted in a non-Leuconostoc, heterologous host and is able to drive dextran synthesis.

Amino Acid Sequence↗
PubMed1997

Characterization of strains of Leuconostoc mesenteroides by analysis of soluble whole-cell protein pattern, DNA fingerprinting and restriction of ribosomal DNA.

Of 215 leuconostocs isolated from field grass, natural whey cultures and water-buffalo milk, 178 were identified as Leuconostoc mesenteroides ssp. mesenteroides while 37 strains could not be identified. Biochemical characterization allowed seven groups to be defined. Representative strains of each group and different habitat and nine reference strains were selected for further analyses. Protein profiles appeared suitable for species discrimination, but did not differentiate between the three subspecies of Leuc. mesenteroides. The technique also showed some differences among equivocal strains. DNA fingerprinting for most strains of Leuc. mesenteroides ssp. mesenteroides examined showed a different restriction pattern from that of the type strain. Ribotyping was not useful for discriminating species and subspecies of the genus Leuconostoc: Leuc. mesenteroides ssp. mesenteroides and ssp. dextranicum showed the same ribopattern as Leuc. lactis while Leuc. mesenteroides ssp. cremoris exhibited a pattern distinct from all the other species examined. On the basis of ARDRA-PCR, two main groups could be distinguished: the larger group included Leuc. mesenteroides, Leuc. lactis, Leuc. pseudomesenteroides and some unidentifiable strains; the second one included Leuc. citreum, Leuc. fallax, Weissella paramesenteroides and some unidentified strains.

Animals↗
PubMed1999

Characterization of pFR18, a small cryptic plasmid from Leuconostoc mesenteroides ssp. mesenteroides FR52, and its use as a food grade vector.

A 1.8-kb cryptic plasmid pFR18 was isolated from Leuconostoc mesenteroides ssp. mesenteroides FR52 and characterized. The identification of single-stranded DNA intermediate (ssDNA) in Leuconostoc demonstrated that the replication of pFR18 is directed by a rolling-circle mechanism (RCR). Sequence analysis revealed a single open reading frame (rep18) encoding a putative 335-amino acid protein homologous to the pT181 replicase. Furthermore, a putative double strand origin similar to that of the pT181 plasmid family was identified. A cloning vector was developed on the basis of the pFR18 replicon by inserting an erythromycin resistance cassette within a non-essential region of the plasmid. The resulting construction was able to transform Lactobacillus sake and various species of Leuconostoc. It was stable in L. mesenteroides, however, the segregational stability of a pFR18 derivative containing large Escherichia coli DNA fragments was affected. Nevertheless, the new RCR plasmid pFR18 may be useful for the construction of food grade vectors.

Amino Acid Sequence↗
PubMed1999

Cloning and molecular characterization of the citrate utilization citMCDEFGRP cluster of Leuconostoc paramesenteroides.

The citMCDEFGRP cluster from Leuconostoc paramesenteroides involved in citrate utilization was cloned and its nucleotide sequence determined. Homology of the inferred gene products with characterized enzymes reveals that citP encodes the citrate permease P, citC the citrate ligase and citDEF the subunits of the citrate lyase of Leuconostoc. Moreover, it suggests that citM encodes a Leuconostoc malic enzyme. Analysis of citrate consumption by and citrate lyase activity of Lc. paramesenteroides J1[pCITJ1] showed that its citrate permease and its citrate lyase are induced by the presence of citrate in the growth medium. Southern blot analysis demonstrated that the citMCDEFGRP cluster is located in a plasmid.

Bacterial Proteins↗
PubMed1985

Vancomycin-resistant streptococci or Leuconostoc sp.

Two strains of gram-positive cocci highly resistant to vancomycin (MICs of 512 and 1,024 micrograms/ml) were isolated from blood cultures in two compromised patients. These organisms were identified as Leuconostoc spp. Leuconostoc spp. are gram-positive cocci found in vegetables and dairy products; they had not been isolated previously from clinical specimens. The susceptibility of eight Leuconostoc spp. strains, including the two clinical isolates, to 23 antimicrobial agents was determined.

Adult↗