Comparative assessment of the bacterial communities associated with Anopheles darlingi immature stages and their breeding sites in the Brazilian Amazon

BACKGROUND

The neotropical anopheline mosquito Anopheles darlingi is a major malaria vector in the Americas. Studies on mosquito-associated microbiota have shown that symbiotic bacteria play a major role in host biology. Mosquitoes acquire and transmit microorganisms over their life cycle. Specifically, the microbiota of immature forms is largely acquired from their aquatic environment. Therefore, our study aimed to describe the microbial communities associated with An. darlingi immature forms and their breeding sites in the Coari municipality, Brazilian Amazon.

METHODS

Larvae, pupae, and breeding water were collected in two different geographical locations. Samples were submitted for DNA extraction and high-throughput 16S rRNA gene sequencing was conducted. Microbial ecology analyses were performed to explore and compare the bacterial profiles of An. darlingi and their aquatic habitats.

RESULTS

We found lower richness and diversity in An. darlingi microbiota than in water samples, which suggests that larvae are colonized by a subset of the bacterial community present in their breeding sites. Moreover, the bacterial community composition of the immature mosquitoes and their breeding water differed according to their collection sites, i.e., the microbiota associated with An. darlingi reflected that in the aquatic habitats where they developed. The three most abundant bacterial classes across the An. darlingi samples were Betaproteobacteria, Clostridia, and Gammaproteobacteria, while across the water samples they were Gammaproteobacteria, Bacilli, and Alphaproteobacteria.

CONCLUSIONS

Our findings reinforce the current evidence that the environment strongly shapes the composition and diversity of mosquito microbiota. A better understanding of mosquito-microbe interactions will contribute to identifying microbial candidates impacting host fitness and disease transmission.

Non-inhibitory levels of oxygen during cultivation increase freeze-drying stress tolerance in Limosilactobacillus reuteri DSM 17938

The physiological effects of oxygen on Limosilactobacillus reuteri DSM 17938 during cultivation and the ensuing properties of the freeze-dried probiotic product was investigated. On-line flow cytometry and k-means clustering gating was used to follow growth and viability in real time during cultivation. The bacterium tolerated aeration at 500 mL/min, with a growth rate of 0.74 ± 0.13 h^-1 which demonstrated that low levels of oxygen did not influence the growth kinetics of the bacterium. Modulation of the redox metabolism was, however, seen already at non-inhibitory oxygen levels by 1.5-fold higher production of acetate and 1.5-fold lower ethanol production. A significantly higher survival rate in the freeze-dried product was observed for cells cultivated in presence of oxygen compared to absence of oxygen (61.8% ± 2.4% vs. 11.5% ± 4.3%), coinciding with a higher degree of unsaturated fatty acids (UFA:SFA ratio of 10 for air sparged vs. 3.59 for N₂ sparged conditions.). Oxygen also resulted in improved bile tolerance and boosted 5'nucleotidase activity (370 U/L vs. 240 U/L in N₂ sparged conditions) but lower tolerance to acidic conditions compared bacteria grown under complete anaerobic conditions which survived up to 90 min of exposure at pH 2. Overall, our results indicate the controlled supply of oxygen during production may be used as means for probiotic activity optimization of L. reuteri DSM 17938.

Challenging the current norm: Does health related quality of life data from reference populations accurately reflect baseline values in breast cancer patients? An observational cohort study comparing EORTC QLQ-C30 scores between the general Swedish population and baseline scores in breast cancer patients

BACKGROUND

Increased overall survival in breast cancer patients has led to a growing recognition of long-term effects of cancer treatment of patients' quality of life. Health related quality of life (HRQoL) data, as measured by patient reported outcome measures (PROMs), is increasingly incorporated into clinical practice and research. A commonly used method current available to interpret HRQoL PROMs data is by comparison to reference values, often obtained from sampling of the general population. The aim of this study was to assess whether HRQoL reference values derived from the general population are an accurate representation of the baseline values of an outpatient breast clinic population.

METHODS

A prospective observational cohort study was conducted by obtaining EORTC QLQ-C30 values for all patients offered an appointment in the outpatient breast clinic. These results were then compared to published baseline values in the general Swedish population, matched by gender and age.

RESULTS

568 questionnaires were returned with a response rate of 81,1 %. The outpatient breast clinic cohort reported a higher grade of symptoms, lower function and lower quality of life compared to the equivalent reference population.

CONCLUSION

This study challenges the assumption that the reference values accurately reflect those of the study population which clinicians and researchers need to account for in study design and clinical practice.

Characterization of Bacterial Communities in Breeding Waters of Anopheles darlingi in Manaus in the Amazon Basin Malaria-Endemic Area

The microbiota in mosquito breeding waters can affect ovipositing mosquitoes, have effects on larval development, and can modify adult mosquito-gut bacterial composition. This, in turn, can affect transmission of human pathogens such as malaria parasites. Here, we explore the microbiota of four breeding sites for Anopheles darlingi, the most important malaria vector in Latin America. The sites are located in Manaus in the Amazon basin in Brazil, an area of active malaria transmission. Using 16S rRNA gene sequencing by MiSeq, we found that all sites were dominated by Proteobacteria and Firmicutes and that 94% of the total number of reads belonged to 36 operational taxonomic units (OTUs) identified in all sites. Of these, the most common OTUs belonged to Escherichia/Shigella, Staphylococcus, and Pseudomonas. Of the remaining 6% of the reads, the OTUs found to differentiate between the four sites belonged to the orders Burkholderiales, Actinomycetales, and Clostridiales. We conclude that An. darlingi can develop in breeding waters with different surface-water bacteria, but that the common microbiota found in all breeding sites might indicate or contribute to a suitable habitat for this important malaria vector.

Impact of the fermentation parameters pH and temperature on stress resilience of Lactobacillus reuteri DSM 17938

This study was undertaken to investigate the impact of culture pH (4.5-6.5) and temperature (32-37 °C) on the stress resilience of Lactobacillus reuteri DSM 17938 during freeze-drying and post freeze-drying exposure to low pH (pH 2) and bile salts. Response-surface methodology analysis revealed that freeze-drying survival rates [Formula: see text] were linearly related to pH with the highest survival rate of 80% when cells were cultured at pH 6.5 and the lowest was 40% when cells were cultured at pH 4.5. The analysis further revealed that within the chosen temperature range the culture temperature did not significantly affect the freeze-drying survival rate. However, fermentation at pH 4.5 led to better survival rates when rehydrated cells were exposed to low pH shock or bile salts. Thus, the effect of pH on freeze-drying survival was in contrast to effects on low pH and bile salts stress tolerance. The rationale behind this irreconcilability is based on the responses being dissimilar and are not tuned to each other. Culturing strain DSM 17938 at pH values higher than 5.5 could be a useful option to improve the survivability and increase viable cell numbers in the final freeze-dried product. However, the dissimilar responses for the process- and application parameters tested here suggest that an optimal compromise has to be found in order to obtain the most functional probiotic product possible.

Survival and phosphate solubilisation activity of desiccated formulations of Penicillium bilaiae and Aspergillus niger influenced by water activity

The impact of formulation and desiccation on the shelf life of phosphate (P)-solubilising microorganisms is often under-studied, particularly relating to their ability to recover P-solubilisation activity. Here, Penicilllium bilaiae and Aspergillus niger were formulated on vermiculite (V) alone, or with the addition of protectants (skimmed milk (V + SM) and trehalose (V + T)), and on sewage sludge ash with (A + N) and without nutrients (A), and dried in a convective air dryer. After drying, the spore viability of P. bilaiae was greater than that of A. niger. V formulations achieved the highest survival rates without being improved by the addition of protectants. P. bilaiae formulated on V was selected for desiccation in a fluidised bed dryer, in which several temperatures and final water activities (aw) were tested. The highest spore viability was achieved when the formulation was dried at 25 °C to a final aw >0.3. During three months' storage, convective air dried formulations were stable for both strains, except in the presence of skimmed milk for P. bilaiae which saw a decrease in spore viability. In the fluidised bed-dried formulations, when aw >0.3, the loss in viability was higher, especially when stored at 20 °C, than at aw <0.1. P-solubilisation activity performed on ash was preserved in most of the formulations after desiccation and storage. Overall, a low drying temperature and high final aw positively affected P. bilaiae viability, however a trade-off between higher viability after desiccation and shelf life should be considered. Further research is needed to optimise viability over time and on more sustainable carriers.

Hybrid Drug Delivery Patches Based on Spherical Cellulose Nanocrystals and Colloid Titania-Synthesis and Antibacterial Properties

Spherical cellulose nanocrystal-based hybrids grafted with titania nanoparticles were successfully produced for topical drug delivery. The conventional analytical filter paper was used as a precursor material for cellulose nanocrystals (CNC) production. Cellulose nanocrystals were extracted via a simple and quick two-step process based on first the complexation with Cu(II) solution in aqueous ammonia followed by acid hydrolysis with diluted H₂SO₄. Triclosan was selected as a model drug for complexation with titania and further introduction into the nanocellulose based composite. Obtained materials were characterized by a broad variety of microscopic, spectroscopic, and thermal analysis methods. The drug release studies showed long-term release profiles of triclosan from the titania based nanocomposite that agreed with Higuchi model. The bacterial susceptibility tests demonstrated that released triclosan retained its antibacterial activity against Escherichia coli and Staphylococcus aureus. It was found that a small amount of titania significantly improved the antibacterial activity of obtained nanocomposites, even without immobilization of model drug. Thus, the developed hybrid patches are highly promising candidates for potential application as antibacterial agents.

Formulation and stabilization of an Arthrobacter strain with good storage stability and 4-chlorophenol-degradation activity for bioremediation

Chlorophenols are widespread and of environmental concern due to their toxic and carcinogenic properties. Development of less costly and less technically challenging remediation methods are needed; therefore, we developed a formulation based on micronized vermiculite that, when air-dried, resulted in a granular product containing the 4-chlorophenol (4-CP)-degrading Gram-positive bacterium Arthrobacter chlorophenolicus A6. This formulation and stabilization method yielded survival rates of about 60% that remained stable in storage for at least 3 months at 4 °C. The 4-CP degradation by the formulated and desiccated A. chlorophenolicus A6 cells was compared to that of freshly grown cells in controlled-environment soil microcosms. The stabilized cells degraded 4-CP equally efficient as freshly grown cells in two different set-ups using both hygienized and non-treated soils. The desiccated microbial product was successfully employed in an outdoor pot trial showing its effectiveness under more realistic environmental conditions. No significant phytoremediation effects on 4-CP degradation were observed in the outdoor pot experiment. The 4-CP degradation kinetics from both the microcosms and the outdoor pot trial were used to generate a predictive model of 4-CP biodegradation potentially useful for larger-scale operations, enabling better bioremediation set-ups and saving of resources. This study also opens up the possibility of formulating and stabilizing also other Arthrobacter strains possessing different desirable pollutant-degrading capabilities.

Perinatal health services organization for preterm births: a multinational comparison

OBJECTIVE

To explore population characteristics, organization of health services and comparability of available information for very low birth weight or very preterm neonates born before 32 weeks' gestation in 11 high-income countries contributing data to the International Network for Evaluating Outcomes of Neonates (iNeo).

STUDY DESIGN

We obtained population characteristics from public domain sources, conducted a survey of organization of maternal and neonatal health services and evaluated the comparability of data contributed to the iNeo collaboration from Australia, Canada, Finland, Israel, Italy, Japan, New Zealand, Spain, Sweden, Switzerland and UK.

RESULTS

All countries have nationally funded maternal/neonatal health care with >90% of women receiving prenatal care. Preterm birth rate, maternal age, and neonatal and infant mortality rates were relatively similar across countries. Most (50 to >95%) between-hospital transports of neonates born at non-tertiary units were conducted by designated transport teams; 72% (8/11 countries) had designated transfer and 63% (7/11 countries) mandate the presence of a physician. The capacity of 'step-down' units varied between countries, with capacity for respiratory care available in <10% to >75% of units. Heterogeneity in data collection processes for benchmarking and quality improvement activities were identified.

CONCLUSIONS

Comparability of healthcare outcomes for very preterm low birth weight neonates between countries requires an evaluation of differences in population coverage, healthcare services and meta-data.

Hypertensive disorders of pregnancy and outcomes of preterm infants of 24 to 28 weeks' gestation

OBJECTIVE

To examine the relationship between hypertensive disorders of pregnancy (HDPs) and mortality and major morbidities in preterm neonates born at 24 to 28 weeks of gestation.

STUDY DESIGN

Using an international cohort, we retrospectively studied 27 846 preterm neonates born at 24⁰ to 28⁶ weeks of gestation during 2007 to 2010 from 6 national neonatal databases. The incidence of HDP was compared across countries, and multivariable logistic regression analyses were conducted to examine the association of HDP and neonatal outcomes including mortality to discharge, bronchopulmonary dysplasia, severe brain injury, necrotizing enterocolitis and treated retinopathy of prematurity.

RESULTS

The incidence of HDP in the entire cohort was 13% (range 11 to 16% across countries). HDP was associated with reduced odds of mortality (adjusted odds ratio (aOR) 0.77; 95% confidence interval (CI) 0.67 to 0.88), severe brain injury (aOR 0.74; 95% CI 0.62 to 0.89) and treated retinopathy (aOR 0.82; 95% CI 0.70 to 0.96), but increased odds of bronchopulmonary dysplasia (aOR 1.16; 95% CI 1.05 to 1.27).

CONCLUSIONS

In comparison with neonates born to mothers without HDP, neonates of HDP mothers had lower odds of mortality, severe brain injury and treated retinopathy, but higher odds of bronchopulmonary dysplasia. The impact of maternal HDP on newborn outcomes was inconsistent across outcomes and among countries; therefore, further international collaboration to standardize terminology, case definition and data capture is warranted.

Coetzeea brasiliensis gen. nov., sp. nov. isolated from larvae of Anopheles darlingi

A Gram-stain-negative, rod-shaped strain, Braz8T, isolated from larvae of Anopheles darlingi was investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain Braz8T was related most closely to species of the genus Thorsellia, with 95.6, 96.5 and 96.6 % similarity to the type strains of Thorsellia anophelis, Thorsellia kandunguensis and Thorsellia kenyensis, respectively, and formed a separate branch in the phylogenetic tree next to the monophyletic cluster of the genus Thorsellia. Chemotaxonomic data supported the allocation of the strain to the family Thorselliaceae. The major fatty acids were C18 : 1ω7c, C16 : 0 and C14 : 0. The quinone system was composed of ubiquinones Q-8 and Q-7 (1 : 0.3), the predominant polar lipids were diphosphatidylglycerol and phosphatidylglycerol, and the polyamine pattern showed the major compound putrescine. However, qualitative and quantitative differences in the major polyamine, polar lipid profile and fatty acid patterns distinguished strain Braz8T from species of the genus Thorsellia. Phylogenetic analysis based on 16S rRNA gene sequences, average nucleotide identity, DNA-DNA hybridization, multilocus sequence analysis as well as physiological and biochemical tests distinguished strain Braz8T both genotypically and phenotypically from the three Thorsellia species but also showed its placement in the family Thorselliaceae. Thus, strain Braz8T is considered to represent a novel species of a new genus most closely related to the genus Thorsellia, for which the name Coetzeea brasiliensis gen. nov., sp. nov. is proposed. The type strain of Coetzeea brasiliensis is Braz8T (=LMG 29552T=CIP 111088T).

Proposal of Thorsellia kenyensis sp. nov. and Thorsellia kandunguensis sp. nov., isolated from larvae of Anopheles arabiensis, as members of the family Thorselliaceae fam. nov

Two Gram-negative, rod-shaped strains, T2.1(T) and W5.1.1(T), isolated from larvae of the mosquito Anopheles arabiensis, were investigated using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity studies, strains T2.1(T) and W5.1.1(T) were shown to belong to the genus Thorsellia, both showing 97.8 % similarity to the type strain of Thorsellia anophelis, with 98.1 % similarity to each other. Chemotaxonomic data supported the allocation of the strains to the genus Thorsellia: their major fatty acids were C18 : 1ω7c, C16 : 0 and C14 : 0 and they harboured a ubiquinone Q-8 quinone system and a polyamine pattern with the major compound 1,3-diaminopropane. Qualitative and quantitative differences in their polar lipid profiles distinguished strains T2.1(T) and W5.1.1(T) from each other and from T. anophelis. Average nucleotide identity (ANI), DNA-DNA hybridization, multilocus sequence analysis (MLSA) as well as physiological and biochemical tests allowed T2.1(T) and W5.1.1(T) to be distinguished both genotypically and phenotypically from each other and from the type strain of T. anophelis. Thus, we propose that these isolates represent two novel species of the genus Thorsellia, named Thorsellia kenyensis sp. nov. (type strain T2.1(T) = CCM 8545(T) = LMG 28483(T) = CIP 110829(T)) and Thorsellia kandunguensis sp. nov. (type strain W5.1.1(T) = LMG 28213(T) = CIP 110794(T)). Furthermore, phylogenetic analysis based on nearly full-length 16S rRNA gene sequences showed that the genus Thorsellia forms a separate branch, distinct from the families Enterobacteriaceae, Pasteurellaceae and Orbaceae. As a consequence, a new family Thorselliaceae fam. nov. is proposed. An emended description of Thorsellia anophelis is also provided.

Formulations for freeze-drying of bacteria and their influence on cell survival

Cellular water can be removed to reversibly inactivate microorganisms to facilitate storage. One such method of removal is freeze-drying, which is considered a gentle dehydration method. To facilitate cell survival during drying, the cells are often formulated beforehand. The formulation forms a matrix that embeds the cells and protects them from various harmful stresses imposed on the cells during freezing and drying. We present here a general method to evaluate the survival rate of cells after freeze-drying and we illustrate it by comparing the results obtained with four different formulations: the disaccharide sucrose, the sucrose derived polymer Ficoll PM400, and the respective polysaccharides hydroxyethyl cellulose (HEC) and hydroxypropyl methyl cellulose (HPMC), on two strains of bacteria, P. putida KT2440 and A. chlorophenolicus A6. In this work we illustrate how to prepare formulations for freeze-drying and how to investigate the mechanisms of cell survival after rehydration by characterizing the formulation using of differential scanning calorimetry (DSC), surface tension measurements, X-ray analysis, and electron microscopy and relating those data to survival rates. The polymers were chosen to get a monomeric structure of the respective polysaccharide resembling sucrose to a varying degrees. Using this method setup we showed that polymers can support cell survival as effectively as disaccharides if certain physical properties of the formulation are controlled.

Impact of matrix properties on the survival of freeze-dried bacteria

BACKGROUND

Disaccharides are, in general, the first choice as formulation compounds when freeze-drying microorganisms. Although polysaccharides and other biopolymers are considered too large to stabilise and interact with cell components in the same beneficial way as disaccharides, polymers have been reported to support cell survival. In the present study we compare the efficiency of sucrose and the polymers Ficoll, hydroxyethylcellulose, hydroxypropylmethylcellulose and polyvinylalcohol to support the survival of three bacterial strains during freeze drying. The initial osmotic conditions were adjusted to be similar for all formulations. Formulation characterisation was used to interpret the impact that different compound properties had on cell survival.

RESULTS

Despite differences in molecular size, both sucrose and the sucrose-based polymer Ficoll supported cell survival after freeze drying equally well. All formulations became amorphous upon dehydration. Scanning electron microscopy and X-ray diffraction data showed that the discerned differences in structure of the dry formulations had little impact on the survival rates. The capability of the polymers to support cell survival correlated with the surface activity of the polymers in a similar way for all investigated bacterial strains.

CONCLUSION

Polymer-based formulations can support cell survival as effectively as disaccharides if formulation properties of importance for maintaining cell viability are identified and controlled.

Antimicrobial resistance in colonizing group B Streptococci before the implementation of a Swedish intrapartum antibiotic prophylaxis program

The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-μg disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) >256 mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-μg oxacillin disks showed a homogenous population with a mean inhibition zone of 20 mm. A change in the present oxacillin breakpoints for GBS is suggested.

Biological preservation of plant derived animal feed with antifungal microorganisms: safety and formulation aspects

During storage of moist animal feed, growth of detrimental fungi causing spoilage, or being mycotoxigenic or pathogenic, is a severe problem. Addition of biopreservative yeasts or lactic acid bacteria can significantly reduce this problem. However, their use requires several careful considerations. One is the safety to the animal, humans and the environment, tightly connected to legal aspects and the need for pre-market authorisation when supplementing feed with microorganisms. Although both yeasts and lactic acid bacteria are considered comparatively safe organisms due to low production of toxic metabolites, it is of great importance to understand the mechanisms behind the biopreservative abilities. Another important issue concerns practical aspects, such as the economic production of large amounts of the organisms and the development of a suitable formulation giving the organisms a long shelf life. These aspects are discussed and a recommendation of this review is that both safety and formulation aspects of a specific microbe should be considered at an early stage in the selection of new organisms with biopreservation potential.

Impact and risk factors for early-onset group B streptococcal morbidity: analysis of a national, population-based cohort in Sweden 1997-2001

OBJECTIVES

To study early-onset group B streptococcal (EOGBS) morbidity, mortality, and maternal risk factors.

DESIGN

Observational, population-based, retrospective. Data from national registers and medical records.

SETTING

Sweden, 1997-2001.

POPULATION

Cohort of 640 infants with a diagnosis of GBS infection out of 435 070 live births.

METHOD

Infants with diagnoses GBS sepsis (P36.0) and/or pneumonia (P23.3) were analysed. In cases with P36.0, register data were validated against infant and maternal medical records. Odds ratios (OR) were estimated by multiple logistic regression.

MAIN OUTCOME MEASURES

Incidence of EOGBS morbidity, mortality, frequency of maternal risk factors and administration of intrapartum antibiotics.

RESULTS

There were 319 cases with EOGBS sepsis. Blood culture verified 174 cases. There were 145 with clinical sepsis and 180 with pneumonia only. The incidences were 0.40, 0.33, and 0.41 per 1000 live births, respectively. The mortality was 7.5, 0.7, and 2.2% in respective groups. The frequencies of established maternal risk factors were: membrane rupture > or =18 hours, 44%; prematurity, 26%; temperature during labour > or =38 degrees C, 22%. Novel maternal risk factors identified in verified cases were gestational age (GA) of 37 completed weeks (OR 3.5, 1.8-6.5) and gestational diabetes (OR 3.7, 1.8-8.5). When including clinical sepsis, also epidural anaesthesia, infant large for GA, postmaturity, and high maternal age were significant risk factors.

CONCLUSION

The incidence of verified EOGBS disease was 0.4 per 1000 live births with a total burden of EOGBS morbidity approximately three times higher. GA of 37 completed weeks and gestational diabetes were identified as additional significant risk factors.

Optimisation and comparison of liquid and dry formulations of the biocontrol yeast Pichia anomala J121

The biocontrol yeast Pichia anomala J121 can effectively reduce mould growth on moist cereal grains during airtight storage. Practical use of microorganisms requires formulated products that meet a number of criteria. In this study we compared different formulations of P. anomala. The best way to formulate P. anomala was freeze-drying. The initial viability was as high as 80%, with trehalose previously added to the yeast. Freeze-dried products could be stored at temperatures as high as 30 degrees C for a year, with only a minor decrease in viability. Vacuum-drying also resulted in products with high storage potential, but the products were not as easily rehydrated as freeze-dried samples. Upon desiccating the cells using fluidised-bed drying or as liquid formulations, a storage temperature of 10 degrees C was required to maintain viability. Dependent on the type of formulation, harvesting of cells at different nutritional stresses affected the initial viabilities, e.g. the initial viability for fluidised-bed-dried cells was higher when the culture was fed with excess glucose, but for freeze-drying it was superior when cells were harvested after depletion of carbon. Using micro-silos we found that the biocontrol activity remained intact after drying, storage and rehydration for all formulations.

Freeze-drying of Lactobacillus coryniformis Si3—effects of sucrose concentration, cell density, and freezing rate on cell survival and thermophysical properties

Freeze-drying is commonly used to stabilize lactic acid bacteria. Many factors have been reported to influence freeze-drying survival, including bacterial species, cell density, lyoprotectant, freezing rate, and other process parameters. Lactobacillus coryniformis Si3 has broad antifungal activity and a potential use as a food and feed biopreservative. This strain is considered more stress sensitive, with a low freeze-drying survival, compared to other commercialized antifungal lactic acid bacterial strains. We used a response surface methodology to evaluate the effects of varying sucrose concentration, cell density and freezing rate on Lb. coryniformis Si3 freeze-drying survival. The water activity of the dry product, as well as selected thermophysical properties of importance for freeze-drying; degree of water crystallization and the glass transition temperature of the maximally freeze concentrated amorphous phase (Tg') were determined. The survival of Lb. coryniformis Si3 varied from less than 6% to over 70% between the different conditions. All the factors studied influenced freeze-drying survival and the most important factor for survival is the freezing rate, with an optimum at 2.8 degrees C/min. We found a co-dependency between freezing rate and formulation ingredients, indicating a complex system and the need to use statistical tools to detect important interactions. The degree of water crystallization decreased and the final water activity increased as a function of sucrose concentration. The degree of water crystallization and Tg' was not affected by the addition of 10(8)-10(10) CFU/ml. At 10(11) CFU/ml, these thermophysical values decreased possibly due to increased amounts of cell-associated unfrozen water.

Advances in preservation methods: keeping biosensor microorganisms alive and active

The ability of bacteria to sense their surroundings can be employed to measure the bioavailability and toxicity of pollutants. However, long-term maintenance of both viability and activity of the sensor bacteria is required for the development of cell-based devices for environmental monitoring. To meet these demands, various techniques to conserve such bacteria have been reported, including freeze drying, vacuum drying, continuous cultivation, and immobilisation in biocompatible polymers of organic or inorganic origin. Much effort has been invested in merging these bacterial preservation schemes with the construction of sensor cell arrays on platforms such as biochips or optic fibres, hopefully leading to effective miniaturised whole-cell biosensor systems. These approaches hold much promise for the future. Nevertheless, their eventual implementation in practical devices calls for significant enhancement of current knowledge on formulation of reporter microorganisms.

Survival of the biocontrol yeast Pichia anomala after long-term storage in liquid formulations at different temperatures, assessed by flow cytometry

AIMS

Investigate the survival of liquid formulations of the biocontrol yeast Pichia anomala J121 at different temperatures, and develop a system for comparative studies of different storage conditions and formulations.

METHODS AND RESULTS

The survival of P. anomala in liquid formulations with lactose, starch and trehalose amendments was measured during prolonged storage at temperatures ranging from -20 to +30 degrees C. The relative survival of the stored cells was rapidly estimated by flow cytometry. After 4 weeks incubation at 4 and 10 degrees C, 75-90% of the cells were viable, with no significant differences between the various formulations. Supplementing the storage buffer with lactose or trehalose increased the survival after longer incubations (8 and 12 weeks) at all temperatures (-20 to 30 degrees C). Trehalose was the most effective protectant at 20 and 30 degrees C (>20% viable cells after 12 weeks at 20 degrees C). The biocontrol activity was maintained after formulation and prolonged storage of P. anomala.

CONCLUSIONS

The storage potential of liquid formulated P. anomala cells can be increased by supplementation with lactose or trehalose. The combination of a custom made incubation chamber and flow cytometry was suitable to evaluate stability of P. anomala formulations.

SIGNIFICANCE AND IMPACT OF THE STUDY

Liquid formulated P. anomala have a long shelf life. The developed test system can be used to study different formulations of other biocontrol agents.

Extremely preterm cesarean delivery: a clinical study

OBJECTIVES

To describe indications for cesarean section for extremely preterm delivery, peri- and postoperative complications and perinatal outcome.

DESIGN

A case-referent study with clinical follow-up.

SETTING

A tertiary perinatal center.

POPULATION

All deliveries at gestational age <28 weeks at Umeå University Hospital in 1997-2003. For preterm cesarean section referents were women with elective first-time term cesarean section.

METHODS

Indications for cesarean section delivery were assessed. Peri- and postoperative complications, asphyxia, and infant survival at discharge were described.

RESULTS

The cesarean section rate was 75%, in one third the operation was considered as difficult. Indications for extremely preterm abdominal delivery were severe disease during pregnancy and delivery complications. Six out of ten cesarean sections were performed on fetal indication. Nonisthmic incision was performed in 20% of cases. No major postoperative complications and few minor postoperative complications were noted. Irrespective of mode of delivery, few of the infants had severe asphyxia.

CONCLUSION

In balancing the risks of complications related to the surgical procedure against the purported benefits of the infant, this study adds support to the argument to deliver even extremely preterm infants by cesarean section.

Short-term outcome after active perinatal management at 23-25 weeks of gestation. A study from two Swedish perinatal centres. Part 3: neonatal morbidity

AIM

To determine major neonatal morbidity in surviving infants born at 23-25 weeks, and to identify maternal and infant factors associated with major morbidity.

METHODS

The medical records of 224 infants who were delivered at two tertiary care centres in 1992-1998 were reviewed retrospectively. At these centres, policies of active perinatal and neonatal management were universally applied. Of the 213 liveborn infants, 140 (66%) survived to discharge. Data were analysed by gestational age and considered in three time periods. Logistic regression models were used to identify factors associated with morbidity.

RESULTS

Of the survivors, 6% had intraventricular haemorrhage grade > or = 3 (severe IVH) or periventricular leukomalacia (PVL), 15% retinopathy of prematurity > or = stage 3 (severe ROP) and 36% bronchopulmonary dysplasia (BPD). On logistic regression analysis, severe IVH or PVL was associated with duration of mechanical ventilation (odds ratio, OR: 1.53 per 1-wk increment in duration; 95% confidence interval, CI: 1.01-2.33). Severe ROP was associated with the presence of a patent ductus arteriosus (PDA) (OR: 3.31; 95% CI: 1.11-9.90) and birth in time period 3 versus time periods 1 and 2 combined (OR: 6.28; 95% CI: 2.10-18.74). BPD was associated with duration of mechanical ventilation (OR: 2.71 per 1-wk increment in duration; 95% CI: 1.76-4.18) and with the presence of any obstetric complication (OR: 2.67; 95% CI: 1.07-6.65). Gestational age and birthweight were not associated with major morbidity. Of all survivors, 81% were discharged home without severe IVH, PVL or severe ROP.

CONCLUSIONS

Increased survival as a result of active perinatal and neonatal management was associated with favourable morbidity rates compared with those in recent studies. Among survivors born at 23-25 weeks, neither gestational age nor birthweight was a significant determinant of major morbidity.

Short-term outcome after active perinatal management at 23-25 weeks of gestation. A study from two Swedish tertiary care centres. Part 2: infant survival

AIM

To determine neonatal survival rates based on both foetal (stillborn) and neonatal deaths among infants delivered at 23-25 wk, and to identify maternal and neonatal factors associated with survival.

METHODS

The medical records of 224 infants who were delivered in two tertiary care centres in 1992-1998 were reviewed retrospectively. At these centres, policies of active perinatal and neonatal management were universally applied. Data were analysed by gestational age groups and considered in three time periods. Logistic regression models were used to identify factors associated with survival.

RESULTS

The rate of foetal death was 5%. Of infants born alive, 63% survived to discharge. Survival rates including foetal deaths in the denominator at 23, 24 and 25 wk were 37%, 61% and 74%, respectively, and survival rates excluding foetal deaths were 43%, 63% and 77%, respectively. Of infants born with 1-min Apgar scores of 0-1, 43% survived. In the total cohort, survival rates including foetal deaths in the denominator increased from 52% in time period 1 to 61% in time period 2 and 74% in time period 3 (p < 0.02). On multivariate logistic regression analysis, higher birthweight (OR: 1.91 per 100 g increment; 95% CI: 1.45-2.52), female gender (OR: 3.33; 95% CI: 1.65-6.75), administration of antenatal steroids (OR: 2.95; 95% CI: 1.46-5.98) and intrauterine referral from a peripheral hospital (OR: 2.35; 95% CI: 1.18-4.68) were associated with survival. Apgar score < or = 3 at 1 min (OR: 0.46; 95% CI: 0.22-0.95) was associated with decreased survival. The use of antenatal steroids was protective at 23-24 wk (OR: 5.2; 95% CI: 2.0-13.7), but not at 25 wk.

CONCLUSIONS

Active perinatal management that included universal initiation of neonatal intensive care virtually eliminated intrapartum stillbirths and delivery room deaths, and resulted in survival rates that compare favourably with those of recent studies. However, the policies of active care postponed death in non-survivors. Individual variations in outcome in relation to the infant's condition at birth as reflected by the Apgar scores preclude the making of treatment decisions in the delivery room.

Caesarean section increases the risk of hospital care in childhood for asthma and gastroenteritis

OBJECTIVE

To investigate if caesarean section (CS) increases the risk for childhood asthma and gastroenteritis with reference made to children born with vaginal delivery (VD).

METHODS

Retrospective study of data from linked Swedish medical service registers--Medical Birth Registry (MBR) and Hospital Discharge Registry (HDR). Data were obtained from women without any background/perinatal morbidity noted, and from children without any neonatal complications. Children that had reached at least 1 year of age and were found in the HDR were considered as cases, whereas children not found in the HDR or hospitalized for other causes than asthma or gastroenteritis were defined as controls. Odds ratios (OR) stratified for year of birth, maternal age, parity and smoking in early pregnancy were calculated. Investigations were made comparing the risk for in hospital treatment for asthma or gastroenteritis in CS children and in VD siblings of CS children. The overall inpatient morbidity in CS and VD children were also investigated.

RESULTS

The OR for asthma in CS children was 1.31 [95% confidence interval (CI) 1.23-1.40]. The same OR, 1.31, was found for gastroenteritis (95% CI 1.24-1.38). The OR for CS children having experienced both asthma and gastroenteritis was further increased (1.74, 95% CI 1.36-2.23). The risk for asthma in VD siblings of CS children was not significantly increased, whereas VD siblings experienced a slightly increased risk for gastroenteritis. CS children had an increased overall in hospital morbidity when compared to VD children.

CONCLUSION

There is a significant increase of the risk for developing symptoms of asthma and/or gastroenteritis that motivates admission for hospital care in CS children older than 1 year. It is speculated that a disturbed intestinal colonization pattern in CS children may be a common pathogenic factor.

Actin filament polymerization regulates gliding motility by apicomplexan parasites

Host cell entry by Toxoplasma gondii depends critically on actin filaments in the parasite, yet paradoxically, its actin is almost exclusively monomeric. In contrast to the absence of stable filaments in conventional samples, rapid-freeze electron microscopy revealed that actin filaments were formed beneath the plasma membrane of gliding parasites. To investigate the role of actin filaments in motility, we treated parasites with the filament-stabilizing drug jasplakinolide (JAS) and monitored the distribution of actin in live and fixed cells using yellow fluorescent protein (YFP)-actin. JAS treatment caused YFP-actin to redistribute to the apical and posterior ends, where filaments formed a spiral pattern subtending the plasma membrane. Although previous studies have suggested that JAS induces rigor, videomicroscopy demonstrated that JAS treatment increased the rate of parasite gliding by approximately threefold, indicating that filaments are rate limiting for motility. However, JAS also frequently reversed the normal direction of motility, disrupting forward migration and cell entry. Consistent with this alteration, subcortical filaments in JAS-treated parasites occurred in tangled plaques as opposed to the straight, roughly parallel orientation observed in control cells. These studies reveal that precisely controlled polymerization of actin filaments imparts the correct timing, duration, and directionality of gliding motility in the Apicomplexa.

Toxoplasma evacuoles: a two-step process of secretion and fusion forms the parasitophorous vacuole

Rapid discharge of secretory organelles called rhoptries is tightly coupled with host cell entry by the protozoan parasite Toxoplasma gondii. Rhoptry contents were deposited in clusters of vesicles within the host cell cytosol and within the parasitophorous vacuole. To examine the fate of these rhoptry-derived secretory vesicles, we utilized cytochalasin D to prevent invasion, leading to accumulation of protein-rich vesicles in the host cell cytosol. These vesicles lack an internal parasite and are hence termed evacuoles. Like the mature parasite-containing vacuole, evacuoles became intimately associated with host cell mitochondria and endoplasmic reticulum, while remaining completely resistant to fusion with host cell endosomes and lysosomes. In contrast, evacuoles were recruited to pre-existing, parasite-containing vacuoles and were capable of fusing and delivering their contents to these compartments. Our findings indicate that a two-step process involving direct rhoptry secretion into the host cell cytoplasm followed by incorporation into the vacuole generates the parasitophorous vacuole occupied by TOXOPLASMA: The characteristic properties of the mature vacuole are likely to be determined by this early delivery of rhoptry components.

Genotyping of the capsule gene cluster (cps) in nontypeable group B streptococci reveals two major cps allelic variants of serotypes III and VII

Forty group B Streptococcus (GBS) isolates obtained from Europe and the United States previously reported to be nontypeable (NT) by capsule serotype determination were subjected to buoyant density gradient centrifugation. From nearly half of the isolates capsule-expressing variants could be selected. For characterization of the remaining NT-GBS isolates, the capsule operon (cps) was amplified by the long-fragment PCR technique and compared by restriction fragment length polymorphism (RFLP) analysis. The patterns from serotype reference isolates (n = 32) were first determined and used as a comparison matrix for the NT-GBS isolates. Using two restriction enzymes, SduI and AvaII, cluster analysis revealed a high degree of similarity within serotypes but less than 88% similarity between serotypes. However, serotypes III and VII were each split in two distant RFLP clusters, which were designated III(1) and III(2) and VII(1) and VII(2), respectively. Among the isolates that remained NT after repeated Percoll gradient selections, two insertional mutants were revealed. Both were found in blood isolates and harbored insertion sequence (IS) elements within cpsD: one harbored IS1548, and the other harbored IS861. All other NT-GBS isolates could, by cluster analysis, be referred to different serotypes by comparison to the RFLP reference matrix. In pulsed-field gel electrophoresis of SmaI-restricted chromosomal DNA, patterns from allelic type 1 and 2 isolates were essentially distributed in separate clusters in serotypes III and VII. A covariation with insertion sequence IS1548 in the hylB gene was suggested for serotype III, since allelic type III(1) harboring IS1548 in hylB, clustered separately. The variation in serotype VII was not dependent on the presence of IS1548, which was not detected at any position in the type VII chromosome.

Implementation of service screening with mammography in Sweden: from pilot study to nationwide programme

Establishment of mammography screening in Sweden has progressed logically from pilot study through clinical trials to service screening. Screening with mammography for early detection of breast cancer has been provided by all Sweden's 26 county councils since 1997. It took 23 years from the initial pilot study through clinical trials to the establishment of mammography service screening throughout Sweden. In the screening rounds completed by 1995-96, and provided by all but one county council, 1040000 women participated, corresponding to 81% of those invited. The national average recall rate was 2.2%, and consequently 23000 women were recalled for additional investigations. Eleven county councils invited women aged 40-74, six invited women aged 50-69, the remaining eight invited women between both these age intervals. Mammography outside screening programmes-clinical mammography-is available throughout Sweden. About 100000 women a year were referred for clinical mammography and about 50% of these were either younger or older than those invited for screening. A negative relation between the use of clinical mammography and participation in the screening programmes was noticed.

Toxoplasma gondii uses sulfated proteoglycans for substrate and host cell attachment

Toxoplasma gondii is an obligate intracellular parasite that actively invades a wide variety of vertebrate cells, although the basis of this pervasive cell recognition is not understood. We demonstrate here that binding to the substratum and to host cells is partially mediated by interaction with sulfated glycosaminoglycans (GAGs). Addition of excess soluble GAGs blocked parasite attachment to serum-coated glass, thereby preventing gliding motility of extracellular parasites. Similarly, excess soluble GAGs decreased the attachment of parasites to human host cells from a variety of lineages, including monocytic, fibroblast, endothelial, epithelial, and macrophage cells. The inhibition of parasite attachment by GAGs was observed with heparin and heparan sulfate and also with chondroitin sulfates, indicating that the ligands for attachment are capable of recognizing a broad range of GAGs. The importance of sulfated proteoglycan recognition was further supported by the demonstration that GAG-deficient mutant host cells, and wild-type cells treated enzymatically to remove GAGs, were partially resistant to parasite invasion. Collectively, these studies reveal that sulfated proteoglycans are one determinant used for substrate and cell recognition by Toxoplasma. The widespread distribution of these receptors may contribute to the broad host and tissue ranges of this highly successful intracellular parasite.

What do we really know about the cost-effectiveness of telemedicine?

Telemedicine is still in its infancy, but undergoing rapid development. It is very difficult to evaluate telemedicine. We performed a literature survey (Medline). During the period 1990-8, over 1500 articles on telemedicine were published. Of these, 246 mentioned economic aspects in the abstract (16%). We selected 29 studies although few had demonstrated cost-effectiveness. Benefits for the patients in the form of reduced travel and waiting time must often be weighed against increased provider costs. Up to now, telemedicine in general has not had any significant effect on medical practice, or the structure and organization of health-care. In order to utilize the potential of telemedicine, its integration with traditional health-care is very important. There are country-specific variations in the health systems that make it difficult to generalize the results from one country to another.

Time-lapse video microscopy of gliding motility in Toxoplasma gondii reveals a novel, biphasic mechanism of cell locomotion

Toxoplasma gondii is a member of the phylum Apicomplexa, a diverse group of intracellular parasites that share a unique form of gliding motility. Gliding is substrate dependent and occurs without apparent changes in cell shape and in the absence of traditional locomotory organelles. Here, we demonstrate that gliding is characterized by three distinct forms of motility: circular gliding, upright twirling, and helical rotation. Circular gliding commences while the crescent-shaped parasite lies on its right side, from where it moves in a counterclockwise manner at a rate of approximately 1.5 microm/s. Twirling occurs when the parasite rights itself vertically, remaining attached to the substrate by its posterior end and spinning clockwise. Helical gliding is similar to twirling except that it occurs while the parasite is positioned horizontally, resulting in forward movement that follows the path of a corkscrew. The parasite begins lying on its left side (where the convex side is defined as dorsal) and initiates a clockwise revolution along the long axis of the crescent-shaped body. Time-lapse video analyses indicated that helical gliding is a biphasic process. During the first 180(o) of the turn, the parasite moves forward one body length at a rate of approximately 1-3 microm/s. In the second phase, the parasite flips onto its left side, in the process undergoing little net forward motion. All three forms of motility were disrupted by inhibitors of actin filaments (cytochalasin D) and myosin ATPase (butanedione monoxime), indicating that they rely on an actinomyosin motor in the parasite. Gliding motility likely provides the force for active penetration of the host cell and may participate in dissemination within the host and thus is of both fundamental and practical interest.

Toxoplasma gondii resides in a vacuole that avoids fusion with host cell endocytic and exocytic vesicular trafficking pathways

Toxoplasma gondii actively penetrates its vertebrate host cell to establish a nonfusigenic compartment called the parasitophorous vacuole (PV) that has previously been characterized primarily in phagocytic cells. To determine the fate of this unique compartment in nonphagocytic cells, we examined the trafficking of host cell proteins and lipids in Toxoplasma-infected fibroblasts using quantitative immunofluorescence and immunoelectron microscopy. Toxoplasma-containing vacuoles remained segregated from all levels of the endocytic pathway, as shown by the absence of delivery of transferrin receptors, mannose phosphate receptors, and the lysosomal-associated protein LAMP1 to the vacuole. The PV was also inaccessible to lipids (DiIC16, and GM1) that were internalized from the plasma membrane via the endocytic system. In contrast, vacuoles containing dead parasites or zymosan sequentially acquired both endosomal and lysosomal protein markers and host lipids, reflecting the competency of fibroblasts to process phagocytic vacuoles. The mature PV often lies adjacent to the host cell Golgi, suggesting that it may intersect with vesicles from the exocytic pathway. Despite this proximity, the PV was inaccessible to nitrobenzadiazole-labeled sphingolipids exported from the Golgi and did not contain the host protein markers AP1 or beta-COP. Our results demonstrate that Toxoplasma resides in a compartment that excludes delivery of protein and lipid components from the host cell endocytic and exocytic pathways.

Heel lancing in term new-born infants: an evaluation of pain by frequency domain analysis of heart rate variability

The aim of the investigation was to assess pain by frequency domain analysis of heart rate variability (HRV) during a routine heel lancing procedure in term new-born infants. Beat-to-beat heart rate (HR) was recorded in 23 healthy new-born infants on the maternity ward during blood sampling for neonatal screening. A sham heel prick prior to the sharp lancing procedure was performed randomly in half of the infants. Spectral analysis of HRV was assessed for each of the following sequences: (1) baseline (2) sham heel prick (3) sharp heel prick and (4) squeezing the heel for blood sampling. The response to the sham prick did not differ significantly from the sharp prick. Compared with the baseline, sharp lancing gave rise to minor increases in HR and variability in the low frequency band of the spectral analysis. A clear stress response was provoked when the heel was squeezed for blood sampling, indicated by an increased HR and a decreased spectral power in the high frequency band (i.e. lower vagal tone). The different stress responses during the lancing and the squeezing of the heel were clearly illustrated when principal component analysis was applied and the vectors for the changes in HR and spectral pattern were indicated. In conclusion, the squeezing of the heel is the most stressful event during the heel prick procedure.

A screening for BRCA1 mutations in breast and breast-ovarian cancer families from the Stockholm region

To identify BRCA1 germ-line mutations in the breast and breast-ovarian cancer families in the Stockholm region, a total of 127 families were screened. DNA from 174 patients from these families were studied using various mutation screening techniques, followed by direct DNA sequencing. Mutations were identified in 7 of 20 families with breast and ovarian cancer and in one family with ovarian cancer only, whereas only 1 family of 106 with breast cancer showed a mutation. Thus, germ-line mutations in BRCA1 were found in one-third of the families with both breast and ovarian cancer, but in only 1% of the breast cancer families. The low frequency of germ-line mutations in the site-specific breast cancer families means that other genes are likely to segregate in these families.

Moderate frequency of BRCA1 and BRCA2 germ-line mutations in Scandinavian familial breast cancer

Previous studies of high-risk breast cancer families have proposed that two major breast cancer-susceptibility genes, BRCA1 and BRCA2, may account for at least two-thirds of all hereditary breast cancer. We have screened index cases from 106 Scandinavian (mainly southern Swedish) breast cancer and breast-ovarian cancer families for germ-line mutations in all coding exons of the BRCA1 and BRCA2 genes, using the protein-truncation test, SSCP analysis, or direct sequencing. A total of 24 families exhibited 11 different BRCA1 mutations, whereas 11 different BRCA2 mutations were detected in 12 families, of which 3 contained cases of male breast cancer. One BRCA2 mutation, 4486delG, was found in two families of the present study and, in a separate study, also in breast tumors from three unrelated males with unknown family history, suggesting that at least one BRCA2 founder mutation exists in the Scandinavian population. We report 1 novel BRCA1 mutation, eight additional cases of 4 BRCA1 mutations described elsewhere, and 11 novel BRCA2 mutations (9 frameshift deletions and 2 nonsense mutations), of which all are predicted to cause premature truncation of the translated products. The relatively low frequency of BRCA1 and BRCA2 mutations in the present study could be explained by insufficient screening sensitivity to the location of mutations in uncharacterized regulatory regions, the analysis of phenocopies, or, most likely, within predisposed families, additional uncharacterized BRCA genes.

Assessment of acute pain in preterm infants by evaluation of facial expression and frequency domain analysis of heart rate variability

In ten preterm infants (postconceptional age 27-35 weeks) facial expression and heart rate variability (HRV) were investigated during three situations: (a) the infant at rest in its crib or incubator, (b) provocation of the withdrawal flexor reflex by application of von Frey's hairs, and (c) lancing and squeezing for blood sampling. Video recordings of facial expressions, mixed at random, were categorised as the baby being either undisturbed, disturbed or in pain and a detailed scoring for each situation was performed. Mean heart rate (HR) was calculated and power spectral analysis was assessed on data from segments of 45-s duration from the three procedures. Flexor withdrawal did not evoke visual signs of pain or influence HRV, but caused a slight increase in HR. The lancing and squeezing of the heel evoked a facial expression of pain in all infants. The HR increased and a reduction in both total HRV and power in the low frequency band of the HRV spectrum was seen during blood sampling. The differentiation between painful and non-painful procedures was more apparent when principal component analysis of HRV was applied.