Nasogastric enteral feeding tubes modulate preterm colonization in early life.

BACKGROUND: Preterm infants are generally fed through nasogastric enteral feeding tubes (NEFTs). The aim of this work was to evaluate the role of NEFTs in the initial colonization of the preterm gut and its evolution within the first 2 weeks after birth. METHODS: For this purpose, fecal and NEFT-derived samples from 30 preterm infants hospitalized in a neonatal intensive care unit (NICU) were collected from birth to the second week of life. Samples were cultivated in ten culture media, including three for the isolation of antibiotic-resistant microorganisms. RESULTS: Isolates (561) were identified by 16S ribosomal RNA gene sequencing. Although the first NEFTs inserted into the neonates after birth were rarely colonized, analysis of NEFTs and fecal samples over time revealed a significant increase in bacterial abundance, diversity, and detection frequency. Results showed a parallel colonization between time-matched NEFTs and fecal samples, suggesting an ongoing bidirectional transfer of bacteria from the neonatal gut to the NEFTs and vice versa. CONCLUSIONS: In short-term hospitalization, length is by far the determinant factor for the early colonization of preterm infants. As NEFT populations reflect the bacterial populations that are colonizing the preterm in a precise moment, their knowledge could be useful to prevent the dissemination of antibiotic-resistant strains. IMPACT: The hospital environment modulates preterm colonization immediately after birth. The colonization of preterm feces and NEFTs occurs in parallel. There is an ongoing bidirectional transfer of microorganisms from the neonatal gut to the NEFTs and vice versa. Bacterial communities inside NEFTs could act as reservoirs of antibiotic resistance genes. NEFT populations reflect the bacteria that are colonizing the preterm at a precise moment.

[Dental caries and early childhood development: a pilot study]. / Caries dental y desarrollo infantil temprano. Estudio piloto.

OBJECTIVE: To investigate the association between dental caries and early childhood development in 3-year-olds from Talca, Chile. METHOD: A pilot study with a convenience sample of 3-year-olds from Talca (n = 39) who attend public healthcare centers. Child development was measured by the Psychomotor Development Index (PDI), a screening tool used nationally among pre-school children to assess language development, fine motor skills and coordination areas. Dental caries prevalence was evaluated by decayed, missing, filled teeth (DFMT) and decayed, missing, filled tooth surfaces (DFMS) ceo-d and ceo-s indexes. The children were divided into two groups according to the PDIscore: those with a score of 40 or more were considered developmentally normal (n = 32), and those with a score below 40 were considered as having impaired development (n = 7). RESULTS: The severity of caries (DMFT) was negatively correlated with PDI (r = -0.82), and children with the lowest TEPSI score had the highest DFMT values. The average DMFT in children with normal development was 1.31, and 3.57 for those with impaired development. CONCLUSION: This pilot study indicates that the severity of dental caries is correlated with early childhood development.

RISEinFAMILY project: the integration of families at neonatal intensive care units (NICUs) to empower them as primary caregivers: study protocol for a stepped wedge cluster controlled trial.

BACKGROUND: Family Integrated Care (FICare) has demonstrated positive outcomes for sick neonates and has alleviated the psychological burden faced by families. FICare involves structured training for professionals and caregivers along with the provision of resources to offer physical and psychological support to parents. However, FICare implementation has been primarily limited to developed countries. It remains crucial to assess the scalability of this model in overcoming social-cultural barriers and conduct a cost-effectiveness analysis. The RISEinFAMILY project aims to develop an adapted FICare model that can serve as the international standard for neonatal care, accommodating various cultural, architectural, and socio-economic contexts. METHODS: RISEinFAMILY is a pluri-cultural, stepped wedge cluster controlled trial conducted in Spain, Netherlands, the UK, Romania, Turkey, and Zambia. Eligible participants include infant-family dyads admitted to the Neonatal Intensive Care Unit (NICU) requiring specialised neonatal care for a minimum expected duration of 7 days, provided there are no comprehension barriers. Notably, this study will incorporate a value of implementation analysis on FICare, which can inform policy decisions regarding investment in implementation activities, even in situations with diverse data. DISCUSSION: This study aims to evaluate the scalability and adaptation of FICare across a broader range of geographical and sociocultural contexts and address its sustainability. Furthermore, it seeks to compare the RISEinFAMILY model with standard care, examining differences in short-term newborn outcomes, family mental health, and professional satisfaction. TRIAL REGISTRATION: ClinicalTrials.gov NCT06087666. Registered on 17 October 2023. PROTOCOL VERSION: 19 December 2022; version 2.2.

Serum adiponectin is associated with body composition and cognitive and psychological status in older adults living in long-term nursing homes.

Frailty is a geriatric syndrome characterized by decreasing functional reserves and increasing vulnerability to falls, injuries and declining health, leading to dependence upon caregivers. Frailty is associated not only with physical decline, but also with cognitive and psychological impairments in aging people. Higher serum adiponectin concentration has been linked to better performance on frailty measures but also to worse cognitive status. Nonetheless, several studies have proposed adiponectin as a frailty biomarker. To further delineate the relationship between adiponectin serum levels and frailty-related parameters, we studied a population of 112 long-term nursing home residents (aged 84.9 ±â€¯6.7) and analyzed their serum adiponectin levels in conjunction with frailty-related parameters including body composition, physical fitness, cognitive function, psychological parameters and quality of life. Frailty was assessed following the Fried Frailty Criteria, the Clinical Frailty Scale and the Tilburg Frailty Indicator. In women, higher serum adiponectin levels were associated with lower body weight, body mass index, body fat mass, fat mass/height2, lean mass, lean mass/height2 and smaller waist circumference and hip circumference (p < 0.05). In men, the association was positive (p < 0.05) between serum adiponectin and percentage of fat mass and negative between serum adiponectin and percentage of lean mass. Interestingly, in men, better cognitive function was inversely related to adiponectin (p < 0.05) while decreased anxiety was linked to a higher concentration of adiponectin in women (p < 0.05). According to the Tilburg Frailty Indicator, frail men had lower levels of adiponectin than those who were not frail (p < 0.05). Variables that predicted adiponectin concentration in multiple regression models were different for women and men. In women, lean mass and anxiety were independent negative predictors of blood adiponectin (ß = -0.363, p = 0.002; ß = -0.204, p = 0.067, respectively). In men, the Montreal Cognitive Assessment (MOCA) test was the only parameter to remain significant in the regression model (ß = -439, p = 0.015). The results of our study show that adiponectin is linked to body composition, cognitive function and anxiety in long-term nursing home residents with differential relationships by sex. Further studies should be conducted to determine whether adiponectin is a valid and reliable frailty biomarker.

Gold-decorated magnetic nanoparticles design for hyperthermia applications and as a potential platform for their surface-functionalization.

The integration of noble metal and magnetic nanoparticles with controlled structures that can couple various specific effects to the different nanocomposite in multifunctional nanosystems have been found interesting in the field of medicine. In this work, we show synthesis route to prepare small Au nanoparticles of sizes = 3.9 ± 0.2 nm attached to Fe3O4 nanoparticle cores ( = 49.2 ± 3.5 nm) in aqueous medium for potential application as a nano-heater. Remarkably, the resulted Au decorated PEI-Fe3O4 (Au@PEI-Fe3O4) nanoparticles are able to retain bulk magnetic moment MS = 82-84 Am2/kgFe3O4, with the Verwey transition observed at TV = 98 K. In addition, the in vitro cytotoxicity analysis of the nanosystem microglial BV2 cells showed high viability (>97.5%) to concentrate up to 100 µg/mL in comparison to the control samples. In vitro heating experiments on microglial BV2 cells under an ac magnetic field (H0 = 23.87 kA/m; f = 571 kHz) yielded specific power absorption (SPA) values of SPA = 43 ± 3 and 49 ± 1 µW/cell for PEI-Fe3O4 and Au@PEI-Fe3O4 NPs, respectively. These similar intracellular SPA values imply that functionalization of the magnetic particles with Au did not change the heating efficiency, providing at the same time a more flexible platform for multifunctional functionalization.

[Can vesicoureteral reflux be predicted in infants with urinary infection?]. / ?Se puede precedir el reflujo vesicoureteral en lactantes con infección urinaria?

AIMS: To look forward for a formulae able to predict the presence of vesicoureteral reflux (VUR) in the first urinary tract infection (UTI) in infants. SUBJECTS AND METHODS: We had studied all the diagnosticated first UTI in breast-fed babies in our hospital along 21/2 years. All had been subjects of a renal ultrasound scan, VCUG and CRP test. We have analyzed the result by diagnosis test and logistic regression. RESULTS: We have studied 267 infants aged between 2 days and 24 months old.17,33% manifested UTI caused by germs different than E Coli, 40 subjects presented anomalies in the ultrasound scan and 108 manifested VUR. Oostenbruck s score had been useless in detecting VUR subjects. In the multivariable analysis the two variables of anomalies in the ultrasonographic scan and non E Coli caused UIT were the only ones to presented statistical significance to sign the presence of VUR and of the likeness of VUR of grade > or = 3. The negative probability coefficients for infants with ultrasonographics anomalies and/or UTI non E Coli produced were of 0,78 (IC 0,67-0,90) for all degrees of VUR, 0,25 (IC 0,10-0,52) for VUR with degree > or = 3 and 0 (IC 0-0,67) for VUR with degree > or = 4. CONCLUSIONS: We deduced that in children younger of 24 months old that suffer their first UTI the indication to proceeded with a VCUG could be limited to the subjects with present anomalies in the renal ultrasound scan and/or UTI non E Coli, thought there will precised more studies to confirm this findings.

Chronic musculoskeletal pain in European older adults: Cross-national and gender differences.

BACKGROUND: In an ageing Europe, chronic pain is a major public health problem, but robust epidemiological data are scarce. This study aimed to analyse the prevalence of and factors associated with chronic musculoskeletal pain by gender in older adults of 14 European countries. METHODS: A cross-sectional study was performed from wave 5 of the Survey of Health, Ageing and Retirement in Europe (SHARE). The study included people ≥50 years residing in Austria, Belgium, Czech Republic, Denmark, Estonia, France, Germany, Italy, Luxembourg, the Netherlands, Slovenia, Spain, Sweden and Switzerland. Chronic pain was defined as being bothered by joint and/or back pain for the previous 6 months. Multivariable Poisson regression models with robust variance were performed to analyse prevalence ratio by covariates, stratified by sex. RESULTS: A total of 61,157 participants were included. Overall prevalence of chronic musculoskeletal pain was 35.7% (28.8-31.7), ranging from 18.6% (17.1-20.1) for Switzerland to 45.6% (43.3-47.8) for France. Prevalence was higher in women than in men: 41.3% (40.2-42.4) versus 29.1% (28.0-30.3). Chronic musculoskeletal pain was lower in men aged >75 years (PR = 0.82; 0.72-0.92) than the younger (50-59) group. Separated/divorced status presented opposite effects among men (PR = 0.85; 0.76-0.96) and women (PR = 1.12; 1.03-1.21) compared with married, and unemployment was a significant factor in men (PR = 1.21; 95% CI 1.02-1.43) compared with employed. CONCLUSIONS: Musculoskeletal pain in older European adults is very frequent, especially in women, with large differences depending on the country of residence. Health policy makers should prioritize strategies aimed at improving the prevention and management of chronic musculoskeletal pain in Europe. SIGNIFICANCE: This study provides epidemiological data of chronic musculoskeletal pain in older adults. Reported differences contribute to highlight the relevance of considering a gender perspective in chronic musculoskeletal pain research. Cross-national comparison also offers a map of differences that improves the knowledge of this chronic condition in Europe.

Obesity parameters, physical activity, and physical fitness are correlated with serum dipeptidyl peptidase IV activity in a healthy population.

OBJECTIVE: To determine whether obesity, physical fitness, and physical activity parameters are associated with the enzymatic activity of serum dipeptidyl peptidase IV (sDPPIV) in a sample of healthy women and men. DESIGN AND METHODS: We have correlated parameters of obesity, physical fitness, and physical activity with sDPPIV activity in 374 healthy subjects (age: 60.7 ± 6.9 years, body mass index: 26.1 ± 4.1 kg/m2). Enzymatic activity was analyzed using spectrofluorimetry, body composition was assessed by impedanciometry, physical fitness data were obtained using the Senior Fitness Test, and physical activity data were collected by accelerometer. Pearson's partial correlation analysis was applied to determine the relationship between DPPIV activity and the rest of parameters and significantly correlated variables were introduced into linear regression models to predict DPPIV. RESULTS: Serum DPPIV activity was negatively associated with obesity parameters such as body mass (r = -0.112), body mass index (BMI) (r = -0.147), waist circumference (r = -0.164), waist-to-hip ratio (-0.104), and percentage of fat mass (r = -0.185). Serum DPPIV activity was positively associated with cardiovascular fitness (r = 0.138), total amount of physical activity (r = 0.153), and time spent doing light exercise (r = 0.184). Regression models revealed sex differences in enzyme activity with overall activity higher in women than in men (ß = 0.437, p < 0.001). Further, percent fat mass was an independent negative predictor of DPPIV activity (ß = -0.184, p = 0.001). Serum DPPIV activity was positively predicted based on the amount of time spent doing light physical activity (ß = 0.167, p = 0.001). CONCLUSION: Our results demonstrate that sDPPIV activity is positively associated with healthier parameters regarding fatness, fitness and physical activity.

Variables associated with diagnostic delay in immigrant groups with tuberculosis in Madrid.

OBJECTIVE: To identify variables associated with total diagnostic delay (TDD), patient delay (PD) and health service delay (HSD), among the tuberculous immigrant population in the Autonomous Community of Madrid (ACT). METHODOLOGY: Tuberculosis cases diagnosed in 15 hospitals in the ACT in 2003 were interviewed face-to-face and medical records were reviewed. A descriptive study was conducted, followed by univariate and multivariate analysis using non-conditional logistic regressions. 50th (p50) and 75th (p75) percentiles of the different diagnostic delay components were analysed as dependent variables. RESULTS: For the 296 cases included, the mean TDD was 40.5 days (IQR 16.0-90.0), the PD was 15 days (IQR 6.5-30.0), and the HSD was 5 days (IQR 0.0-30.0). TDD-p75 is associated with seeking primary health care (OR 2.87, 95%CI 1.47-5.58). PD-p75 is associated with identification of fever (OR 0.49, 95%CI 0.25-0.92) and non-identification of cough (OR 1.87, 95%CI 1.05-3.36) as symptoms resulting in health care being sought. The HSD-p75 is associated with primary health care being sought (OR 3.81, 95%CI 1.87-7.78), health cover (OR 15.07, 95%CI 1.96-115.68) and negative smear results at the time of diagnosis (OR 1.98, 95%CI 1.01-3.91). CONCLUSIONS: The HSD needs to be reduced, mainly when health care is sought through the primary care services and among patients with negative smear results.

Sexually transmitted Chlamydia trachomatis, Neisseria gonorrhoeae, and HIV-1 infections in two at-risk populations in Barcelona: female street prostitutes and STI clinic attendees.

OBJECTIVE: To determine the prevalence of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and HIV-1 infections in female street prostitutes and STI clinic attendees in Barcelona. DESIGN: This was a prospective study carried out in two four-month periods over two years. Urine specimens were tested for CT and NG using a PCR pooling algorithm. Among street prostitutes HIV-1 testing in urine was also carried out. RESULTS: The prevalences of CT, NG, and HIV-1 in female street prostitutes (n=301) were 4.7%, 3.7%, and 1.0%, respectively. Women from Eastern Europe had the highest prevalence of CT (p=0.01). Prevalences of CT, NG, and HIV-1 among all clinic attendees (n=536) were 4.3%, 4.5%, and 4.4%, respectively. Prevalence of HIV-1 infection among homosexual men was higher compared with heterosexual men and women (p<0.001). CONCLUSIONS: Overall CT prevalence is currently lower than in other European countries, although it could increase as a result of immigration. Rates of HIV-1 and of NG are higher among homosexual than among heterosexual men.

Magnetically responsive biopolymeric multilayer films for local hyperthermia.

We present a proof of concept on the use of thermomagnetic polymer films (TMFs) as heating devices for magnetic hyperthermia in vitro. The TMFs were prepared through spray assisted layer-by-layer assembly of polysaccharides and magnetic iron oxide nanoparticles, yielding an alternate magnetic-polymer multilayer structure. By applying a remote alternating magnetic field (AMF) (f = 180 kHz; H = 35 kA m-1) we increased the temperature of the TMFs in a thickness-dependent way, up to 12 °C within the first 5 minutes. To test our films as heating substrates for magnetic hyperthermia, a series of in vitro experiments were designed using human neuroblastoma SH-SY5Y cells, known by their tolerance to thermal stress. The application of two AMF cycles (30 minutes each) showed that the exogenous magnetic hyperthermia resulted in an 85% reduction of cell viability. This capacity of the TMFs of hyperthermia-mediated cell killing using a remote AMF opens new options for the treatment of small and superficial tumor lesions by means of remotely-triggered magnetic hyperthermia.

Inducción de remisión con gentamicina y vancomicina oral en enfermedad inflamatoria intestinal de inicio temprano / Very early onset inflammatory bowel disease remission induced with oral gentamicin and vancomycin

La enfermedad inflamatoria intestinal de inicio temprano se manifiesta en pacientes pediátricos antes de los 6 años de edad. Habitualmente se asocia a diversas causas, siendo descrita frecuentemente la disbiosis como factor desencadenante. Esta población presenta comúnmente refractariedad a los tratamientos inmunosupresores más empleados.Presentamos el caso de un paciente con colitis no clasificable y corticodependiente de un año de evolución ingresado en nuestro centro que no había respondido a terapia inmunosupresora intensificada. Se plantea terapia con antibióticos orales como inducción de la remisión del brote de actividad en combinación con su tratamiento inmunomodulador habitual. Si bien inicialmente se obtiene la remisión clínica, el paciente experimenta posteriormente al alta un nuevo brote de actividad siendo necesaria una segunda reinducción con antibióticos que no resulta eficaz, motivando su suspensión. (AU)

Very early onset inflammatory bowel disease occurs in children under 6 years age. It is frequently associated to a diverse ethiology, dysbiosis being usually described as a triggering factor. Commonly, this population is highly resilient to inmmunosuppressant therapies.We report here a medical case of a patient diagnosed with unclassified and steroid-dependent colitis, with a year of evolution, who had no responded to intensified therapy at home, and, therefore, was hospitalized at our centre. Treatment with oral antibiotics was intended as remission induction in combination with his usual inmmunomodulator treatment. Although clinical remission was observed at first stage, a new activity outbreak emerged requiring a second round of antibiotics therapy, which was unsuccessful and currently withdrawned. (AU)

Magnetic heating properties and neutron activation of tungsten-oxide coated biocompatible FePt core-shell nanoparticles.

Magnetic nanoparticles are highly desirable for biomedical research and treatment of cancer especially when combined with hyperthermia. The efficacy of nanoparticle-based therapies could be improved by generating radioactive nanoparticles with a convenient decay time and which simultaneously have the capability to be used for locally confined heating. The core-shell morphology of such novel nanoparticles presented in this work involves a polysilico-tungstate molecule of the polyoxometalate family as a precursor coating material, which transforms into an amorphous tungsten oxide coating upon annealing of the FePt core-shell nanoparticles. The content of tungsten atoms in the nanoparticle shell is neutron activated using cold neutrons at the Heinz Maier-Leibnitz (FRMII) neutron facility and thereby transformed into the radioisotope W-187. The sizeable natural abundance of 28% for the W-186 precursor isotope, a radiopharmaceutically advantageous gamma-beta ratio of γß≈30% and a range of approximately 1mm in biological tissue for the 1.3MeV ß-radiation are promising features of the nanoparticles' potential for cancer therapy. Moreover, a high temperature annealing treatment enhances the magnetic moment of nanoparticles in such a way that a magnetic heating effect of several degrees Celsius in liquid suspension - a prerequisite for hyperthermia treatment of cancer - was observed. A rise in temperature of approximately 3°C in aqueous suspension is shown for a moderate nanoparticle concentration of 0.5mg/ml after 15min in an 831kHz high-frequency alternating magnetic field of 250Gauss field strength (25mT). The biocompatibility based on a low cytotoxicity in the non-neutron-activated state in combination with the hydrophilic nature of the tungsten oxide shell makes the coated magnetic FePt nanoparticles ideal candidates for advanced radiopharmaceutical applications.

Dopamine-glutamate interactions in the prefrontal cortex of the conscious rat: studies on ageing.

The effects of apomorphine, a D1-D2 dopamine receptor agonist, on the extracellular concentration of glutamate were investigated in the medial prefrontal cortex of young, middle-aged and aged rats. In vivo intracerebral perfusions were undertaken in the conscious rat using a concentric push-pull cannula system. Glutamate concentration in the samples were determined by HPLC with fluorometric detection. Apomorphine produced an increase in extracellular concentration of glutamate in medial prefrontal cortex of young rats (178% of baseline) only at 10 microM, but not at 5 and 20 microM. This increase in glutamate concentration induced by apomorphine was significantly attenuated by blockade of D1-D2 dopamine receptors with haloperidol. Apomorphine, at 10 microM, failed to induce an increase in extracellular concentration of glutamate in the prefrontal cortex of middle-aged and aged rats. However, at 20 microM, apomorphine induced an increase in glutamate concentration in the prefrontal cortex of middle-aged rats, but not in aged rats. These data indicate that an interaction between dopamine and glutamate exists in the medial prefrontal cortex and that this interaction deteriorates with age.

Effects of neurotensin on the release of glutamic acid in the prefrontal cortex and striatum of the rat.

The effects of neurotensin (NT) on the extracellular concentrations of excitatory amino acids (EAA) glutamic acid (GLU) and aspartic acid (ASP) in the medial prefrontal cortex (MPC) and striatum (ST) of the conscious rat have been studied. NT was infused directly into these two structures for 10 min at doses of 10, 100 and 1000 nM. In the MPC, NT produced a dose-related increase of GLU. Also, NT produced a delayed increase of ASP at the highest dose. In ST, NT at doses of 10, 100 and 1000 nM produced no effect on GLU and ASP. It is suggested that the increase of GLU and ASP in the MPC could be due to a direct effect of NT on pyramidal cortical neurones. On the contrary, it is suggested that a direct interaction NT-GLU does not exist in the ST of the rat.

Selective release of glutamine and glutamic acid produced by perfusion of GLP-1 (7-36) amide in the basal ganglia of the conscious rat.

Glucagon-like peptide 1 (GLP-1)(7-36) amide, a member of the family of glucagon and related peptides, synthesized by intestinal L cells, has a well-defined distribution in rat brain. In addition, specific GLP-1(7-36) amide receptors have also been localized in some regions of the brain, which suggests that this novel gut-brain peptide has a role in brain function. Accordingly, we investigated the effects of this peptide on the release of amino acid neurotransmitters in the basal ganglia of conscious rats after its perfusion through a concentric "push-pull" cannula system with an artificial cerebrospinal fluid. To obtain stable basal levels of amino acids, the basal ganglia were perfused with an artificial cerebrospinal fluid for 2 h at a flow rate of 20 microliters/min and then with GLP-1(7-36) amide for 10 min, followed by 40 min poststimulation perfusion. GLP-1(7-36) amide produced an immediate increase (p less than 0.01) of the extracellular levels of glutamine and glutamic acid in the basal ganglia. By contrast, this peptide has no effect on the levels of aspartic acid, glycine, and serine. Because glutamine is a metabolic precursor of glutamic acid and is synthesized almost exclusively in astrocytes, these findings suggest a stimulatory effect of GLP-1(7-36) amide on astrocytes and/or neurons of the rat basal ganglia.

Characteristics of lactobacilli isolated from dry fermented sausages.

A study of the microflora of Spanish dry fermented sausages showed a similar pattern to that observed in other sausages during ripening. Lactic acid bacteria and organisms growing on Mannitol-salt-agar increased during the first five days, remaining at constant levels afterwards. From MRS agar, 368 strains were isolated and characterized. All Lactobacillus strains (343) could be separated into three groups according to their reactions in the API-50 L system. The biochemical characteristics of the Lactobacillus strains analyzed were those typical of isolates from sausages and other meat products. The extracellular and intracellular lipolytic activities of some strains of the three groups were also studied. It is concluded that lipolytic activity of lactobacilli is mainly directed against mono- and diglycerides and short-chain fatty acid triglycerides.

Antibacterial activity of Lactobacillus sake isolated from dry fermented sausages.

Lactic acid bacteria isolated from Spanish dry fermented sausages were screened for antagonistic activities under conditions that eliminated the effects of low pH and hydrogen peroxide. From 720 isolates tested 119 were inhibitory to Lactobacillus fermentum CECT285. The isolates showing the largest inhibitory activity exhibited an antagonistic effect against several other lactobacilli and the selected foodborne pathogens Staphylococcus aureus and Listeria monocytogenes. Comparison of the antimicrobial spectra of the supernatants suggested that the inhibitory compounds were not identical. The isolates were tentatively characterized as Lactobacillus sake. One of the isolates, L. sake 148 was chosen for further study. The compound excreted by L. sake 148 was active against various lactobacilli and several Gram-positive foodborne bacteria, but not against the Gram-negative bacteria tested. The antagonistic effects were almost eliminated by treatment with proteases, whereas they were heat resistant and bacteriostatic rather than bacteriocidal.

Sakacin M, a bacteriocin-like substance from Lactobacillus sake 148.

The antagonistic activity of Lactobacillus sake 148 was evaluated during its growth on complex broth media and in a semisynthetic defined medium (SDM) with various supplements. The antagonistic activity was a growth-associated property, being detected and quantified when L. sake 148 was grown at either 4, 8, 16, 25 or 32 degrees C. The concentrated culture supernatant of L. sake 148 was subjected to purification by lyophilization and gel filtration. The purification procedure resulted in a small increase in its specific activity (7-fold) and in a low recovery of the original inhibitory activity (8%). Gel filtration analysis of the partially purified activity on Sephadex G-50 revealed an apparent molecular weight of 4640. The partially purified antagonistic activity of L. sake 148 was destroyed by treatment with proteolytic enzymes. However, the antagonistic activity was resistant to heat, having D-values at 121, 135 and 150 degrees C of 23.8, 17.4 and 15.2 min, respectively.