Global transcriptome analysis of Pseudomonas aeruginosa NT06 response to potassium chloride, sodium lactate, sodium citrate, and microaerophilic conditions in a fish ecosystem.

Pseudomonas aeruginosa is an opportunistic pathogen that recently has been increasingly isolated from foods, especially from minimally processed fish-based products. Those are preserved by the addition of sodium chloride (NaCl) and packaging in a modified atmosphere. However, the current trends of minimizing NaCl content may result in an increased occurrence of P. aeruginosa. NaCl can be replaced with potassium chloride (KCl) or sodium salts of organic acids. Herein, we examined the antimicrobial effects of KCl, sodium lactate (NaL), sodium citrate (NaC), and sodium acetate (NaA) against P. aeruginosa NT06 isolated from fish. Transcriptome response of cells grown in medium imitating a fish product supplemented with KCl and KCl/NaL/NaC and maintained under microaerophilic conditions was analysed. Flow cytometry analysis showed that treatment with KCl and KCl/NaL/NaC resulted in changed metabolic activity of cells. In response to KCl and KCl/NaL/NaC treatment, genes related to cell maintenance, stress response, quorum sensing, virulence, efflux pump, and metabolism were differentially expressed. Collectively, our results provide an improved understanding of the response of P. aeruginosa to NaCl alternative compounds that can be implemented in fish-based products and encourage further exploration of the development of effective methods to protect foods against the P. aeruginosa, underestimate foodborne bacteria.

Effects of Fermentation Temperature, Drying Temperature, Caliber Size, Starter Culture, and Sodium Lactate on Listeria monocytogenes Inactivation During Salami Production.

The effect of fermentation and drying temperatures, caliber, and sodium lactate on Listeria monocytogenes inactivation was studied in salami, produced in a pilot scale, inoculated with 107 CFU/g of Listeria innocua ATCC® 33090 as a surrogate microorganism for L. monocytogenes. Fermentation temperature varied between 24 and 30°C, drying temperature between 14 and 20°C, caliber between 5.1 and 13.2 cm, and sodium lactate initial concentrations in salamis were 0 and 2%. L. innocua counts, pH and water activity were determined in salamis over time. Sodium lactate (2%) decreased pH drop and Listeria inactivation during fermentation. Baranyi & Roberts equation was used to fit the experimental data and to estimate, for each test condition, inactivation rate (k), initial (Y0), and final counts of L. innocua (YEND). Total inactivation was calculated as Y0 minus YEND (Y0-YEND). Then, using a Box Benkhen experimental design, a quadratic model for k and a two-factor interaction model (2FI) for Y0 - YEND were obtained as functions of fermentation temperature, drying temperature, and caliber size. The models predicted that maximum k and Y0 -YEND, -2.62 ± 0.14 log10 CFU/g/day and 4.5 ± 0.1 log10 CFU/g, respectively, would be obtained fermenting at 30°C and drying at 20°C regardless of caliber. Drying at 14°C allowed Listeria growth until a water activity (aw) of 0.92 was reached. Therefore, if initial Listeria contamination is high (3 log10 CFU/g), drying at low temperatures will compromise product safety.

Cerebral Lactate Uptake After Half-Molar Sodium Lactate Therapy in Traumatic Brain Injury: A Brief Report.

Exogenous sodium lactate has many advantages after traumatic brain injury, including intracranial pressure control and alternative energetic supply. It remains unclear, however, whether half-molar sodium lactate (HSL) is effectively incorporated in brain metabolism, which we can verify using the arteriovenous difference in lactate (AVDlac). Hence we compared the AVDlac in patients with severe traumatic brain injury receiving an equiosmolar bolus of sodium lactate or mannitol for intracranial hypertension (IH) treatment. We included 23 patients: 14 received HSL for 25 IH episodes, and nine received mannitol for 19 episodes (total of 44 IH episodes). We observed that the median variation in AVDlac was positive in the group that received HSL (Δ +0.1 [IQR -0.08-0.2] mmol/L), which suggests a net lactate uptake by the brain. On the other hand, it was negative in the group that received mannitol (Δ -0.0 [IQR -0.1 to 0.0] mmol/L), indicating a net lactate export. Finally, there were more positive AVDlac values in the group that received HSL and more negative AVDlac values in the group that received mannitol (Fisher exact p = 0.04). Our study reports the first evidence of a positive AVDlac, which corresponds to a net lactate uptake by the brain, in patients who received HSL for severe TBI. Our results constitute a bedside confirmation of the integration of lactate into the brain metabolism and pave the way for a wider dissemination of sodium lactate in the daily clinical care of patients with traumatic brain injury.

Antibacterial efficacy of nisin, bacteriophage P100 and sodium lactate against Listeria monocytogenes in ready-to-eat sliced pork ham

ABSTRACT The effectiveness of bacteriophage P100, nisin and sodium lactate, individually and in combination, in inhibiting Listeria monocytogenes in ready-to-eat pork ham slices was assessed. The antimicrobials were applied to the surfaces of ready-to-eat pork ham slices, which were inoculated with a mixture of L. monocytogenes. Among the individual antimicrobial treatments, bacteriophage P100 was the most effective, decreasing L. monocytogenes to undetectable levels at zero and 72 h post-infection. Sodium lactate was the least effective treatment. Treatment with nisin at zero h significantly reduced initial cell density (p < 0.05). However, this pattern was not observed at 72 h of storage. A significant difference (p < 0.05) existed between the results of separate bacteriophage and nisin treatments after refrigerated storage, but not immediately upon inoculation of the bacteria. The results showed that the use of bacteriophage P100 is the method of choice for the control of bacteria.

Fighting by sleep-deprived rats as a possible manifestation of panic: effects of sodium lactate

Increased fighting is an effect of desynchronized sleep deprivation (DSD) in rats, and recently this behavior has been suggested to be spontaneous panic and equivalent to panic disorder. In the present study we tested this hypothesis by evaluating the effect of sodium lactate on this aggressiveness, because this substance is recognized to induce spontaneous panic attacks in patients. A total of 186 male albino Wistar rats, 250-350 g, 90-120 days of age, were submitted to DSD (multiple platform method) for 0, 4, or 5 days. At the end of the deprivation period the rats were divided into subgroups respectively injected intraperitoneally with 1.86, 2.98 and 3.72 g/kg of 1 M sodium lactate, or 1.86 and 3.72 g/kg of 2 M sodium lactate. The control animals were submitted to the same procedures but received equivalent injections of sodium chloride. Regardless of DSD time, sleep-deprived animals that received sodium lactate presented a significantly higher mean number of fights (0.13 + or - 0.02 fights/min) and a longer mean time spent in confrontation (2.43 + or - 0.66 s/min) than the controls (0.01 + or - 0.006 fights/min and 0.12 + or - 0.07 s/min, respectively; P<0.01, Student t-test). For the sodium lactate group, concentration of the solution and time of deprivation increased the number of fights, with the mean number of fights and mean duration of fighting episodes being greater with the 2.98 g/kg dose using 1 M lactate concentration. These results support the hypothesis that fighting induced by DSD is probably a spontaneous panic manifestation. However, additional investigations are necessary in order to accept this as a promising animal model for studies on panic disorder

Disociación de la respuesta de alarma ante una mezcla de cristaloides y coloides en la inducción anestésica en cirugía cardíaca

El objetivo de la investigación fue probar si la administración de líquidos durante la inducción de la anestesia, al restaurar el déficit de agua y expandirel volumen intravascular, atenuaria la respuesta hormonal normalmente producida en cirugía. Se realizó un estudio randomizado controlado, en un centro de atención terciaria, en treinta y seis pacientes programados para cirugía electiva de bypass aorto-coronario. Los criterios- de exclusión fueron: función miocárdica severamente- reducida o disfunción renal conocida. Doce pacientes recibieron 10 ml/kg de solución Ringer (grupo baja dosis de cristaloide LDC), 12 pacientes recibieron 15 ml/kg solución Ringer (grupo alta dosis de cristaloide HDC), y 12 pacientes recibieron una combinación de 10 ml/kg de solución Ringer más 10 ml/kg1 de solución hidroxietil-starch (HES) 450.000 daltons, grado de substitución 0,7 (grupo C-HES), dentro de un período de 20 minutos posterior a la inducción de la anestesia (fentanyl, midazolam, pancuronio). El índice cardíaco y el índice sistólico se incrementaron en 20 por ciento y 15 por ciento en el grupo C-HES mientras de al ADH, la renina y la aldosterona disminuyeron (18 por ciento, 18 por ciento, 43 por ciento) respectivamente, luego de la administración de volumen. Luego de la administración de volumen, los niveles plasmáticos de lso sistemas hormonales llamados a responder ante la deshidratación e hipovolemia disminuyeron en el grupo C-HES. En los otros dos grupos no se presentó ninguna mejoría del estado hemodinámico y las hormonas medidas permanecieron en el mismo nivel observado durante la inducción de la anestesia. No hubo diferencias intergrupales en el volumen total administrado o en l balance hídrico al final de la cirugía. La administración de una combinación de soluciones cristaloides y coloides siguiendo la inducción de la anestesia en pacientes con función ventricular preservada, programados para cirugía cardíaca, conduce a atenuar las respuesta normal de los sistemas hormonales que se observa durante los estados de deshidratación e hipovolemia, en tanto que la restricción de líquidos promueve la actividad de dichos sistemas hormales