Infección de un muñón por Leuconostoc spp, reporte de un caso y revisión de la literatura / Infection of a stump by Leuconostoc, a case report and review of the literature

Resumen La infección del muñón después de amputaciones traumáticas tiene una prevalencia hasta del 34%. Las bacterias más frecuentemente aisladas son Staphylococcus aureus, Enterobacterales como Escherichia coli; Pseudomonas aeruginosa, entre otras. Estas infecciones ocurren por la inoculación directa en el momento del trauma o por gérmenes nosocomiales; la realización de curaciones de las heridas con emplastos vegetales es una práctica aún frecuente en zonas rurales de nuestro país pero su relación con infección del sitio operatorio ha sido poco explorada en la literatura. Leuconostoc spp. es un coco Gram positivo encontrado en territorio agrícola y utilizado en la industria de alimentos. Se presenta un caso de infección de un muñón transfemoral por Leuconostoc, después de una amputación traumática del miembro inferior en una paciente previamente sana con una posible asociación a curaciones con emplastos vegetales.

Abstract Infection of a traumatic amputation stump has a prevalence of 34%. The most common bacteria isolated are Staphylococcus aureus, Pseudomonas aeruginosa and Enterobacterales such as Escherichia coli. These infections occur by direct inoculation in the moment of the trauma or by nosocomial germs. Infections secondary to manipulation of the wounds with vegetable plasters have few case reports in the literature. Leuconostoc spp. is a Gram-positive coccobacillus commonly found in agricultural territory and used in the food industry. There are few case reports in the literature about bone infections by Leuconostocs pp. We present a case of an infection of the operative site of a transfemoral stump by Leuconostoc spp. after a traumatic amputation of the lower limb in a previously healthy patient who had a possible association to cures with vegetable plasters.

Antimicrobial activity of characterized Leuconostoc spp. as novel probiotics isolated from Oreochromis spp. (red tilapia) against fish pathogen Edwardsiella tarda

Aims@#This study aimed to isolate and characterize putative new probiotic with antimicrobial properties against common fish pathogens from the gut of Oreochromis spp. (red tilapia). @*Methodology and results@#A total of 28 colonies were isolated from gut of Oreochromis spp. and characterized phenotypically. Eight isolates were selected for probiotic characterization. Temperature, salinity, pH and bile salt tolerance, antibiotic susceptibility and antimicrobial test against selected fish pathogens (Aeromonas hydrophila, Edwardsiella tarda and Staphylococcus aureus subsp. aureus ATCC 25923) were conducted. Characterization studies revealed isolates suited for freshwater environment and exhibited tolerance against wide range of salinity, pH and bile salt. Isolates displayed different antibiotic susceptibility profile, with six exhibited antimicrobial properties against E. tarda. Molecular identification based on 16S rRNA gene sequencing showed 99.44%, 98.59% and 91.21% sequence similarity with Leuconostoc pseudomesenteroides strain 3832T, Leuconostoc lactis strain KCC202369T and Leuconostoc mesenteroides strain 4332T, respectively as compared to known sequence in the GenBank. When identified Leuconostoc spp. were coated on feed pellets, no major decrease in viability over 21 days of storage at 4 °C were observed, with an average of 8 log CFU/mL.@*Conclusion, significance and impact of study@#The characterized species allow further application assessment of the probiotic-supplemented tilapia feed. Host-originated Leuconostoc displayed potential antimicrobial properties against fish pathogen E. tarda. The isolates Leuconostoc is expected to provide protective effect for Oreochromis spp. against edwardsiellosis and to exert beneficial effects more efficiently as compared to commercial probiotics which are not specifically target for Oreochromis spp., thereby indirectly helping fish farmers in achieving economic sustainability and increase affordability of fish.

Report of a case of Leuconostoc lactis bacteremia following intestinal perforation with literature review / 中华全科医师杂志

A 24-year female with abdominal pain and fever for 4 days was admitted. The blood culture showed Leuconostoc growth, and sputum culture showed positive Acinetobacterbaumannii. The diagnosis Leuconostoclactis bacteremia following small intestinal perforation was confirmed; surgical treatment was performed and the infection was controlled by piperacillin sodium and tazobactam combined with tegacycline. Wanfang database, CNKI, PubMed and Embase database up to September 2020 were searched with the keywords of " Leuconostoc lactis" "infection" "bacteraemia" for relevant literature. A total of 32 cases were reported in the literature, of whom 13 (39.4%) were infants, 17 (51.5%) had catheter-related bloodstream infection, and one healthy adult male had bacteremia through gastrointestinal perforation. In 20 patients treated with penicillins-based antibiotics, 18 were cured with an effective rate of 90.0%. The results suggest that Leuconostoc infection is likely to occur in the infants, but adults can still get community-acquired Leuconostoc infection. Most β-lactams are susceptible to Leuconostoc, but some exhibit resistance, so it is recommended to select antimicrobial agents based on drug susceptibility.

Endocarditis caused by Leuconostoc lactis in an infant. Case report / Endocarditis por Leuconostoc lactis en un lactante. Reporte de caso

Abstract Introduction: Infections caused by Leuconostoc lactis are rare and are associated with multiple risk factors. According to the literature reviewed, there are no reported cases of endocarditis caused by this microorganism in the pediatric population. Case presentation: An infant with short bowel syndrome was taken by his parents to the emergency department due to malnutrition. During his prolonged hospital stay, he presented multiple infections, so he required central venous catheter, prolonged enteral tube feeding and parenteral nutrition. In one of his nosocomial infection episodes, peripheral blood cultures were taken, and an echocardiogram was performed, achieving the diagnosis of endocarditis by L. lactis, which was treated with linezolid. After 21 days of treatment, the infectious process was controlled; however, in order to improve his condition and due to another bacteremia episode, he remained hospitalized. Finally, after 113 days, the patient was discharged, and comprehensive outpatient care was ordered. Conclusion: Although rare in the pediatric population, endocarditis by L. lactis should be suspected in patients with multiple risk factors and polymicrobial infections. Timely and specific treatment, as in the reported case, can help avoid future complications.

Resumen Introducción. Las infecciones por Leuconostoc lactis son raras y se asocian a múltiples factores de riesgo; además, de acuerdo con lo revisado en la literatura relevante, no hay reportes de endocarditis causada por este microorganismo en población pediátrica. Presentación del caso. Lactante con síndrome de intestino corto que fue llevado por sus padres al servicio de urgencias por desnutrición. Durante su estancia hospitalaria prolongada, el paciente presentó múltiples infecciones, por lo que requirió catéter venoso central (CVC), alimentación enteral prolongada y nutrición parenteral. En uno de los episodios infecciosos intrahospitalarios se tomaron hemocultivos periféricos y se realizó un ecocardiograma, lo que permitió diagnosticarlo con endocarditis por L. lactis y por lo cual se decidió iniciar manejo con linezolid. Luego de 21 días de tratamiento, la infección fue controlada, pero con el fin de mejorar su estado nutricional y debido a un nuevo episodio de bacteremia, se decidió prolongar su estancia hospitalaria. Finalmente, después de 113 días de hospitalización, fue dado de alta para continuar manejo integral ambulatorio. Conclusión. A pesar de ser una entidad poco frecuente en pediatría, la endocarditis por L. lactis debe sospecharse en pacientes con múltiples factores de riesgo y con infecciones polimicrobianas. Un tratamiento oportuno y específico como el usado en el presente caso puede evitar complicaciones futuras.

Do Kimchi and Cheonggukjang Probiotics as a Functional Food Improve Androgenetic Alopecia? A Clinical Pilot Study

Characterization of a sucrose phosphorylase from Leuconostoc mesenterides for the synthesis of α-arbutin / 生物工程学报

Sucrose phosphorylase (SPase) gene from Leuconostoc mesenteroides ATCC 12291 was synthesised after codon optimization, and inserted into pET-28a plasmid to generate pET-28a-spase. The recombinant strain Escherichia coli BL21 (DE3)/pET-28a-spase was induced for Spase expression. The recombinant protein Spase was purified and characterized. The specific enzyme activity of SPase was 213.98 U/mg, the purification ratio was 1.47-fold, and the enzyme activity recovery rate was 87.80%. The optimal temperature and the optimal pH of the SPase were identified to be 45 °C and 6.5 respectively, and Km, Vmax and kcat of the SPase for sucrose was 128.8 mmol/L, 2.167 μmol/(mL·min), and 39 237.86 min-1. The recombinant SPase was used for α-arbutin production from hydroquinone and the reaction process was evaluated. The optimal conditions for synthesis of α-arbutin by SPase were 40 g/L hydroquinone, 5:1 molar ratio of sucrose and hydroquinone, and 250 U/mL recombinant SPase at pH 7.0 and 30 °C for 24 h in the dark, and then 500 U/mL glucoamylase was added at 40°C for 2.5 h. Under the optimized process, the yield of α-arbutin reached 98 g/L, and the hydroquinone conversion rate was close to 99%. In summary, the recombinant SPase was cloned and characterized, and its application for α-arbutin production was feasible.

Assessment of Leuconostoc spp. invasion in standing sugarcane with cracks internode

Aim: The post-harvest deterioration is most vexing problems of sugar industry and these losses due to Leuconostoc spp. cause enormous depreciation in cane tonnage and recovery. Thus, the objective of this study was to assess the invasion of Leuconostoc spp. in sugarcane. Methodology: Single internode is divided in three layers, viz., rind, first half and second half. Leuconsotoc spp. was grown and identified on specific growth media using juice from three portions of both the internodes (with cracks and without cracks) separately. Total Leuconostoc load, bacterial characterization, total soluble solids (TSS), reducing sugars (RS) and dextran were also determined. Results: The results revealed that cracked portions were incurred with Leuconostoc, however, rind layer had highest load followed by first half than the second half. More RS, high TSS and dextrans were quantified in cracked internode than without crack internode. Rind layer reported to have high RS, TSS and dextrans than the other portions. Interpretation: Canes possessing cracks had higher invasion of Leuconostoc spp., RS and dextran content than the ones lacking cracks leading to higher loss in sucrose content. Thus, there is a need to control these bacteria in sugarcane, especially in standing canes.

Bacteriemia a Leuconostoc mesenteroides, una rara causa de choque séptico

RESUMEN Leuconostoc mesenteroides pertenece a la familia Streptococcaceae. Son cocobacilos gram positivos, intrínsecamente resistentes a múltiples antibióticos por lo que las opciones de tratamiento pueden ser limitadas. Se presenta el caso de una mujer de 28 años que consultó por sensación febril, astenia y malestar general, se diagnostica leucemia linfoblástica aguda en la internación y posteriomente desarrolla choque séptico por bacteriemia a Leuconostoc mesenteroides.

ABSTRACT Leuconostoc mesenteroides belongs to the family Streptococcaceae. They are gram-positive coccobacilli, intrinsically resistant to multiple antibiotics, therefore treatment options may be limited. We present the case of a 28-year-old woman who consulted for febrile sensation, asthenia and malaise. Acute lymphoblastic leukemia was diagnosed during hospitalization and later the patient developed a septic shock due to Leuconostoc mesenteroides bacteremia.

Characteristics of Vegetable Juice Fermented with Lactobacillus plantarum MKHA15 and Leuconostoc mesenteroids MKSR

The objective of this study was to develop fermented vegetable juices that possess antidiabetic and antioxidant activities. Lactobacillus plantarum MKHA15 (MKHA15) and Leuconostoc mesenteroides MKSR (MKSR) were applied to ferment onion, cabbage, and tomato juices at 37℃ and 30℃ for 72 h, respectively, and their functionality was tested using the 12 h hour-fermented juice by MKHA15, and 48 h hour-fermented juice by MKSR. Inhibition of α-glucosidase activity was observed in all fermented juices. The onion juice fermented by MKHA15 showed significantly higher α-glucosidase inhibition activity compared to other juices. All juices showed more than 70% inhibition of α-amylase activity. The DPPH radical scavenging activity of onion juice fermented by MKSR showed significantly lower activity than cabbage and tomato juices; however, no difference was observed between the types of starter cultures. The SOD-like activity of cabbage juice fermented by MKSR was the highest among the fermented juices. The juices fermented by MKHA15 showed higher reducing power than those by MKSR. Therefore, we believe that cabbage, onion and tomato juice fermented by MKHA15 and MKSR would be useful in probiotic juices, as they possess antidiabetic and antioxidant activities.

Analysis of Microbial Contamination and Investigation on Bacteriostatic Efficacy of Compound Balloonflowers and Ephedrine Syrup(Ⅱ) / 中国药学杂志

OBJECTIVE: To analyze the microbial contamination and investigate the bacteriostatic efficacy of compound balloonflowers and ephedrine syrup(Ⅱ). METHODS: The compound balloonflowers and ephedrine syrup(Ⅱ) was analyzed for the bacteriostatic efficacy, content of bacteriostatic agent and C18 column was adopted with gradient elution. The mobile phase consisted of 0.02 mol•L-1 ammonium acetate solution and methanol. The detective wavelength was set at 255 nm. The contaminating bacteria detected in the samples were identified by VITEK2 Campact, MALDI-TOF-MS and 16S rRNA sequencing, and homology analysis was conducted for the contaminating bacteria in the samples from the same enterprise. RESULTS: The bacteriostatic efficacy of the products of one enterprise did not meet the requirements of Chinese Pharmacopoeia(2015 edition). There were excessive and uneven contamination of microorganisms in the samples. The dosages of bacteriostatic agents in some enterprises did not conform to the standard requirements. CONCLUSION: Production enterprises should strictly control the dosages of bacteriostatic agents and the stability of the production process, and strengthen the monitoring of the sterilization effect of the whole production process to improve product quality.

Bacteremia caused by Leuconostoc species : 6-case series / 고신대학교의과대학학술지

Leuconostoc species are Gram-positive coccobacilli and are used in dairy products and are intrinsically resistant to vancomycin. Leuconostoc infections are rare in humans, usually occurring in immune-compromised patients. We describe 6 patients with Leuconostoc bacteremia at Dong-A university hospital between 1990 and 2015. One isolate (L. lactis) was identified to species level using 16S rRNA gene sequencing analysis. All patients had underlying diseases and 5 patients underwent procedures that interrupted the normal integumentary defense. Four patients died within 30 days after being identified as carrying Leuconostoc species.

Characterization of the spoilage lactic acid bacteria in “sliced vacuum-packed cooked ham”

The lactic acid bacteria are involved with food fermentation and in such cases with food spoilage. Considering the need to reduce the lactic acid bacteria growth in meat products, the aim of this work was to enumerated and investigated the lactic acid bacteria present on sliced vacuum-packed cooked ham stored at 4 °C and 8 °C for 45 days by phenotypic and molecular techniques. The quantification showed that the lactic acid bacteria were present from the first day with mean count of 1.98 log cfu/g for the four batches analyzed. The lactic acid bacteria grew rapidly on the samples, and plate counts around 7.59 log cfu/g and 8.25 log cfu/g were detected after 45 days of storage at 4 °C and 8 °C, respectively; storage temperatures studied showed significant influence on the microorganism in study growth. The predominant lactic acid bacteria associated with the spoilage samples at one day of storage includes Lactobacillus sp., the phenotypic overlap Leuconostoc/Weissella sp. and Enterococcus sp. At 45 days of storage at 4 and 8 °C the mainly specie was Lactobacillus curvatus, following by Lactobacillus sakei and Leuconostoc mesentereoides; the Enterococcus sp. was not present in the samples.

Maduración de queso de cabra con cepa autóctona de Leuconostoc mesenteroides aislada de queso artesanal / Ripening of Goat Cheese With a Native Strain of Leuconostoc mesenteroides Isolated from Artisan Cheese

Se elaboró queso de cabra madurado empleando una cepa liofilizada de Leuconostoc mesenteroides como cultivo iniciador, aislada a partir de la flora natural de quesos de cabra, elaborados artesanalmente con leche cruda de cabra del municipio Torres, estado Lara, Venezuela. El proceso de maduración fue de 4 sem, a 14°C y 70% de humedad relativa. Durante el tiempo de maduración, se evaluaron semanalmente los cambios en pH, sólidos totales y parámetros de textura; mientras que el contenido de proteínas, se determinó al inicio y al final del estudio. Al finalizar la maduración, se realizó un estudio con consumidores para evaluar la aceptabilidad de los quesos obtenidos en comparación con un queso control inoculado con una cepa comercial. El contenido de sólidos totales disminuyó entre 23 y 31% a lo largo del estudio (p<0,05), el pH en 6%, mientras que el contenido proteico no registró cambios al final de la maduración. La dureza y gomosidad en los quesos se incrementaron entre 1,64 y 2N; y 0,72 y 0,83N, respectivamente, con la maduración; correlacionándose positivamente con la variación en sólidos totales (R²>0,90) para ambos quesos mientras que la adhesividad y cohesividad no registraron cambios importantes. En la evaluación sensorial, el queso elaborado con L. mesenteroides obtuvo una aceptabilidad promedio del 70%, al compararlo con un queso de cabra obtenido a partir de una cepa comercial de Lactococcus lactis.

A ripened goat cheese was developed using a lyophilized strain of Leuconostoc mesenteroides as starter culture. This strain was isolated from the natural flora of artisan goat cheese made with raw milk in the municipality of Torres, the State of Lara, Venezuela. The maturation process lasted 4 weeks, at 14°C and 70% relative humidity. During the ripening period, changes in pH, total solids, and texture parameters where registered every week, while protein content was determined at baseline and at the end of the study. After maturation was completed, its acceptability was assessed through a consumer test against a control cheese inoculated with a commercial strain. The total solids content fell between 23 and 31% throughout the study (p<0.05), the pH at 6%, while the protein content was unchanged at the end of ripening. The hardness and gumminess in cheese increased between 1,64 and 2N; and 0,72 and 0,83N, respectively, with maturation; their were positively correlated with the variation in total solids (R²>0,90) for both cheeses while adhesiveness and cohesiveness showed no major changes. In the sensory evaluation, the cheese made from L. mesenteroides obtained an average acceptability of 70%, when compared with a goat cheese obtained from a commercial strain of Lactococcus lactis.

Peritonitis Due to Leuconostoc Species in a Patient Receiving Continuous Ambulatory Peritoneal Dialysis / 계명의대학술지

Leuconostoc species are gram-positive cocci and they are rarely pathogenic in human. Leuconostoc infections are commonly associated with immunocompromised status and indwelling medical devices include intravenous catheter, tracheostomy, endotracheal intubation and percutaneous endoscopic gastrostomy. Clinical isolates of Leuconostoc were frequently misidentified, usually as viridans streptococci, but they possess inherent resistance to vancomycin despite sensitivity to most other antibiotics. We present a case of Leuconostoc peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD). A 48-year-old man with hypertensive nephropathy has been treated with peritoneal dialysis, developed peritonitis due to Leuconostoc species. The peritonitis was poorly responded to empirical antibiotics. He was successfully treated with intraperitoneal administration of ampicillin. The dialysis catheter was left in place, and continued to function. To our knowledge, this is the first case of Leuconostoc peritonitis reported in Korea.

Biological characteristics and probiotic effect of Leuconostoc lactis strain isolated from the intestine of black porgy fish

A strain of lactic acid bacteria, Leuconostoc lactis, was isolated from the intestinal tract of black porgy, Sparus macrocephalus, and identified by conventional biochemical characteristics and 16S rDNA gene sequence analysis. The isolated strain had the ability of bile tolerance and resistance to low pH, and survived well in the trypsinase and pepsin solution. But the highly concentrated dose of trypsinase and pepsin affect the viability of the isolated strain. The isolate was resistant to several antibiotics, including Cephalothin, Ceftriaxone, Imipenem and Tobramycin. The isolate could autoaggregate itself and coaggregate with other bacteria in vitro. The autoaggregation percentage increased to 23.29% after 20 h of incubation. The percentage of coaggregation were respectively 31.21%, 29.44%, 10.74%, 16.49%, 24.36%, 24.41% and 20.99% for Vibrio parahaemolyticus, Listeria monocytogenes, Escherichia coli O157, Salmonella typhimurium, Shigella, Staphylococcus aureus and Proteusbacillus vulgaris after 20 h incubation of a mixed suspension. The supernatant of the strain inhibited the growth of several pathogens, such as V.parahaemolyticus, Vibrio harveyi, Vibrio alginolyticus, Staphylococcus aureus, Escherichia coli O157, Salmonella typhimurium, Bacillus subtilis, Proteusbacillus vulgaris and Shigella. These results indicated that the isolate, Leuconostoc lactis, might be an attractive candidate for perspectival strain for probiotics in marine aquaculture.

Exopolysaccharide in Lactobacillus Rhamnosus Pn04 After Co-Culture with Leuconostoc mesenteroides Vtcc-B-643.

Exopolysaccharides (EPS) from lactic acid bacteria (LAB) have many applications in food industry, and pharmaceutical field. To improve EPS production in Lactobacillus rhamnosus PN04 and Leuconostoc mesenteroides VTCC-B-643, these bacteria were co-cultured together. There were shape changes in Lactobacillus rhamnosus into curved rod. Their EPS were estimated after co-cultured. After ethanol precipitation method, the colorimetric method were done using phenol-sulfuric acid assay, the EPS from L. rhamnosus PN04 increased from 2.446 mg/l to 4.228 mg/l while Leuconostoc mesenteroides increased from 3.217 mg/l to 4.712 mg/l. By SDS-PAGE analysis in both straight and curved Lactobacillus rhamnosus, there were the expressed proteins with the estimated molecular weight of 14, 60, 66 kDa while the curved Lactobacillus rhamnosus showed another proteins with molecular weight of 14, 20, 31, 45, 60, 66, 95 kDa. The results suggested that there were the interaction between two these strains. This is the first report showed there were differences in EPS production and protein expression after co-culture of Lactobacillus rhamnosus PN04 and Leuconostoc mesenteroides VTCC-B-643.

Antimicrobial activity of lactic acid bacteria and the spectrum of their biopeptides against spoiling germs in foods

The objective of this study was to isolate LAB from dairy, meat products and agro-industrial wastes and to investigate their antagonist activity. A total of 141 isolates were screened for the inhibitory effect on ten indicator strains in the agar spot test. Results showed that strain LBbb0141 contained antimicrobial compound with wide spectrum that inhibited the growth of ten indicator Gram-positive and Gram-negative strains. The bacteriocin activity attained its maximum value using the MRS agar at initial pH 7.5 and 30°C incubation temperature.

Leuconostoc garlicum: An unusual pathogen in the era of vancomycin therapy.

Leuconostoc garlicum, belonging to the family of Leuconostocaceae, is a catalase-negative, Gram-positive ovoid cocci, intrinsically resistant to vancomycin. Clinical infection by Leuconostoc garlicum is rare. We report a case of respiratory tract infection subsequent to vancomycin therapy.

Bioconversion of ginsenoside Rb1 into compound K by Leuconostoc citreum LH1 isolated from kimchi

About 40 different types of ginsenoside (ginseng saponin), a major pharmacological component of ginseng, have been identified along with their physiological activities. Among these, compound K has been reported to prevent the development of and the metastasis of cancer by blocking the formation of tumors and suppressing the invasion of cancerous cells. In this study, ginsenoside Rb1 was converted into compound K via interaction with the enzyme secreted by ¥â-glucosidase active bacteria, Leuconostoc citreum LH1, extracted from kimchi. The optimum time for the conversion of Rb1 to compound K was about 72 hrs at a constant pH of 6.0 and an optimum temperature of about 30¨¬C. Under optimal conditions, ginsenoside Rb1 was decomposed and converted into compound K by 72 hrs post-reaction (99 percent). Both TLC and HPLC were used to analyze the enzymatic reaction. Ginsenoside Rb1 was consecutively converted to ginsenoside Rd, F2, and compound K via the hydrolyses of 20-C ¥â-(1 ¡æ 6)-glucoside, 3-C ¥â-(1 ¡æ 2)glucoside, and 3-C ¥â-glucose of ginsenoside Rb1.

Estudo do derivado do óleo de Ricinus communis L. (mamona) como agente biocida e redutor da viscosidade produzida por Leuconostoc mesenteroides em indústrias sucroalcooleiras / Study of a Ricinus communis L. (castor oil) derivative as a biocidal agent and viscosity reducer on Leuconostoc mesenteroides in the sugar and alcohol industries

Das sementes da mamona extrai-se o óleo de rícino, utilizado in natura ou em sua forma modificada nas áreas médica, farmacêutica e industrial. Um de seus derivados químicos - o Poliquilgerm® - evidencia propriedades antifúngicas sobre Candida albicans e bacteriostática/ bactericida sobre Escherichia coli no nível de 99,9%. Considerando-se essas propriedades, aplicouse o Poliquilgerm® em culturas de Leuconostoc mesenteroides, uma das espécies de bactéria contaminante dos mostos em indústrias sucroalcooleiras. Esta bactéria quando presente em mostos produz além do ácido láctico, a dextrana, que é um polímero da glicose que aumenta a viscosidade dos fluidos dos processos. No presente trabalho avaliou-se o efeito de diferentes concentrações do Poliquilgerm® sobre a viscosidade produzida por L. mesenteroides em diferentes meios de cultivo, condições de pH, e temperatura. Verificou-se 20,56% de diminuição da viscosidade quando se utilizou 1,0% do produto, além da inibição do crescimento da bactéria após 20 horas em contato com 1,0 e 0,2% de Poliquilgerm®. L. mesenteroides apresentou melhor crescimento em valores de pH 6,0, tanto a 28 como a 33º C, evidenciado pela maior produção de biomassa. Além disso, em meio de cultura neste pH verificou-se maior porcentagem de diminuição da viscosidade em ambas as concentrações utilizadas. Estas mesmas concentrações alcançaram até 100% de diminuição das UFC/mL após 24 horas em contato com o produto, evidenciado por quantificação da biomassa e confirmado mediante plaqueamento pela técnica "Pour Plate".

Castor-oil, extracted from seeds of Ricinus communis L., is normally used in natura or in its modified form in the medical, pharmaceutical and industrial areas. One of its chemical derivates ­ Poliquilgerm® ­ has shown antifungal properties on Candida albicans, and bacteriostatic/bactericide effects on Escherichia coli reaching 99.9%. Considering these features, in the present study Poliquilgerm® was applied in cultures of Leuconostoc mesenteroides, a frequent contaminant bacterium of musts in the sugar and alcohol industries. This bacterium, when a contaminant of must, produces lactic acid as well as dextran, a polymer of glucose which may increase the viscosity of fluids in the operation. The present study evaluated the effect of different concentrations of Poliquilgerm® on viscosity produced by L. mesenteroides cultures under different conditions of various culture media, pH and temperature. A 20.56% decrease in viscosity was verified when 1.0% of the product was used, and bacterium growth inhibition after 20 hours in media with 1.0 and 0.2% of Poliquilgerm®. L. mesenteroides showed a higher growth rate in pH 6.0, at both 28 and 33º C, evidenced by greater biomass production. Also, in the culture media at this pH a greater decrease in viscosity percentages was verified at both concentrations used. The media with these same concentrations reached up to 100% decrease of UFC/mL after 24 hours in the presence of the product, observed by biomass quantification and confirmed by the Pour Plate technique.