[68Ga]Ga-Ornibactin for Burkholderia cepacia complex Infection Imaging Using Positron Emission Tomography.

Bacteria from the Burkholderia cepacia complex are generally considered to be non-pathogenic to the healthy population. However, some of these species may cause serious nosocomial infections in immunocompromised patients; as such, it is essential to diagnose these infections rapidly so that adequate treatment can be initiated. We report here the use of a radiolabeled siderophore, ornibactin (ORNB), for positron emission tomography imaging. We successfully radiolabeled ORNB with gallium-68 with high radiochemical purity and proved that the resulting complex has optimal in vitro characteristics. In mice, the complex did not show excessive accumulation in organs and was excreted in the urine. We demonstrated that the [68Ga]Ga-ORNB complex accumulates at the site of Burkholderia multivorans infection, including pneumonia, in two animal infection models. These results suggest that [68Ga]Ga-ORNB is a promising tool for the diagnosis, monitoring, and evaluation of the therapeutic response to B. cepacia complex infection.

NAS agar is more suitable than McKay agar for primary culture of Streptococcus milleri group (SMG) fastidious bacteria, S. intermedius in particular.

Streptococcus milleri group (SMG) is a group of three streptococcal species (S. anginosus, intermedius and constellatus) that act as opportunist pathogens, among others in cystic fibrosis. Due to their fastidious character, they are both difficult to cultivate and to differentiate from less pathogenic streptococcal species, therefore being most probably underdiagnosed. Semi-selective McKay agar and NAS agar were developed to facilitate SMG recovery from clinical samples; however, direct comparison of recovery rates has not been published yet. We tested the performance of both media on 123 patient samples and demonstrated general superiority of NAS agar for SMG recovery during primary cultivation convincingly. This observation was also confirmed by quantitative drop tests during subculture. Despite the undisputed overall superiority of NAS agar over McKay agar, a smaller fraction of strains grew better on McKay agar. Inter-strain differences were the most probable explanation. Therefore, when economic conditions are not limiting and maximum recovery rate is desirable, both plates are advised to be used in parallel for primary cultivation of clinical samples.

McRAPD unlike MALDI-TOF MS is a suitable candidate for routine discrimination of new Haemophilus influenzae strain acquisition in chronic obstructive pulmonary disease (COPD) and cystic fibrosis.

BACKGROUND AND AIMS: Haemophilus influenzae new strain acquisition has been demonstrated to increase the relative risk of acute exacerbation fourfold in contrast to colonisation or chronic infection by the same strain in chronic obstructive pulmonary disease (COPD). Unfortunately, molecular typing techniques are not suitable for routine use due to cost, labour-intensity and need for special expertise. We tested two techniques potentially useful for routine typing, namely the newly available MALDI-TOF MS and the modified McRAPD compared to MLST as the gold standard. METHODS: In 10 patients (10.8%) suffering from COPD or cystic fibrosis, H. influenzae isolates were recovered repeatedly at different timepoints from the same patient during the study period. This allowed for thirteen pairwise comparisons of typing results in isolates recovered consecutively from the same patient to test the ability of the techniques to uncover new strain acquisition. RESULTS: MLST detected 9 cases of new strain acquisition among the 13 pairwise comparisons. However, MALDI-TOF MS reported all 13 pairs as different and thus new. In contrast, McRAPD was able to differentiate all the new strain acquisitions from pre-existing ones, both by visual inspection of melting profiles and by Relative Significant Difference values. CONCLUSIONS: Unlike MALDI-TOF MS, McRAPD appears to be a suitable candidate for routine discrimination of new strain acquisitions because of its accuracy and, rapid, easy and economic performance.

[Prolonged culture in a humid chamber increases the yields of pathogenic bacteria from the respiratory tract samples of patients suffering from cystic fibrosis].

Current standards of care for cystic fibrosis (CF) patients lack unequivocal recommendations concerning the duration of primary culture of bacteriological samples. With the exception of Burkholderia cepacia (5 days), the minimum recommended duration of primary culture varies between 48 and 72 hours. Our aim was to evaluate the effect of an extended 10-day period of primary culture in a humid chamber in samples acquired from the respiratory tract of patients suffering from CF. Compared to standard culture, prolonged culture in a humid chamber yielded 1.85 times more isolates of pathogenic species in pharyngeal swabs (76 versus 41 isolates) and 1.4 times more isolates in sputum samples (116 versus 82), but only 1.14 times more isolates in nasal swabs (25 versus 22). Prolonged culture was most beneficial for Achromobacter spp. (6 versus 0), Stenotrophomonas maltophilia (16 versus 5) and Pseudomonas aeruginosa (69 versus 49), whereas there was little or no benefit at all for Staphylococcus aureus (87 versus 73) and Moraxella catarrhalis (10 versus 10). Therefore, prolonged culture in a humid chamber may definitely be recommended for pharyngeal swabs and sputum samples obtained from patients suffering from CF to achieve the maximum recovery rate of pathogenic bacteria, in particular non-fermenting Gram-negative rods.

The Streptococcus milleri group in chronic obstructive pulmonary disease.

BACKGROUND AND AIMS: S. anginosus, constellatus and intermedius, also known as the Streptococcus milleri group (SMG) are three streptococcal species more frequently detected in cases of invasive disease, abscesses and empyema in particular. Recent research suggests they play a role in exacerbations of cystic fibrosis (CF). Owing to poor recovery on standard culture media and difficult differentiation from non-pathogenic streptococci, SMG may be underdiagnosed in routine settings. We aimed to establish the incidence of SMG in chronic obstructive pulmonary disease (COPD) patients compared to CF patients and to examine possible links of SMG to exacerbations that plays a key role in progression of COPD. METHODS: Altogether, 90 respiratory tract samples of patients suffering from CF or COPD were examined during the period from July 2012 to December 2013. Semi-selective McKay agar was used for primary cultivation of SMG and MALDI TOF MS was used for species identification that was confirmed by biochemical profiling and specific PCR. RESULTS: We confirmed the presence of SMG in CF (17.6% incidence in adult patients) and newly established its presence in COPD (10.3% incidence). In COPD, SMG was detected in 4 cases of acute exacerbations, where no other bacterial pathogen was detected. In 3/4 cases, increased CRP level indicated bacterial infection as a cause of the exacerbation and in all 3 cases, patients recovered during antibiotic treatment. CONCLUSIONS: Our data indicate SMG may act as opportunist pathogens able to cause exacerbations in COPD.

Performance of pyrosequencing versus MALDI-TOF MS in bacteria identification in chronic lung disease.

Rapid identification of the etiological agent in bacterial infection is necessary for correct diagnosis and appropriate therapy. In general, identification of pure cultures of bacteria using conventional phenotyping techniques requires 4-24 hours. Recently available new molecular technologies offer the potential of same day species identification once pure culture is available. Our aim was to evaluate the performance of rDNA V1 hypervariable region pyrosequencing, and the whole cell MALDI-TOF MS protein profiling in routine species identification. During the period from June 2012 to June 2014, 1.140 pure culture isolates were recovered from 402 samples from 126 patients suffering cystic fibrosis, chronic obstructive pulmonary disease or bronchiectasis. All the isolates were subjected to species identification by both techniques. Unfortunately, pyrosequencing was able to reach the species level in 43.2% of isolates only, whereas MALDI-TOF was clearly superior with 96.8% respectively. The overall sensitivity values also clearly underlined the superiority of MALDI-TOF MS with 96.8% compared to 85.1% achieved by pyrosequencing. Generally, MALDI-TOF MS turned out to be the best suitable technique in routine bacterial identification, whereas pyrosequencing could be recommended as the method of choice particularly in situations where MALDI-TOF MS fails to identify rare species.

Mitochondrial changes in adenocarcinoma of the pancreas.

The aim of our study was to analyse the mitochondrial ultrastructure in primary ductal adenocarcinomas of the pancreas and to compare it with normal pancreatic cells. 52 samples of adenocarcinoma of the pancreas obtained by surgical resection or by endosonographic biopsy were examined. Compared to normal mitochondrial ultrastructure in non-tumorous cells, the mitochondria in cancer cells had a dense matrix and condensed configuration or with lucent-swelling matrix associated with disarrangement and distortion of cristae and partial or total cristolysis. Functionally, these structural alterations presume the presence of hypoxia-tolerant and hypoxia-sensitive cancer cells.

Photosynthetic responses of lettuce to downy mildew infection and cytokinin treatment.

Changes in primary metabolism of lettuce, Lactuca sativa L. (cv. Cobham Green), induced by compatible interaction with the biotrophic oomycete pathogen Bremia lactucae Regel (race BL 16), under two intensities of illumination in the presence and absence of exogenous cytokinins were studied by chlorophyll fluorescence imaging. Thirteen days post-inoculation leaf discs infected by B. lactucae exhibited impairments of photosynthesis associated with biotrophic infections, including: reductions in photosynthetic pigment contents and the maximum quantum yield of photosystem II photochemistry (F(V)/F(M)), inhibition of electron transport (Phi(PSII)) and increased non-photochemical chlorophyll fluorescence quenching (NPQ). Detected changes in photosynthetic parameters correlated with the leaf area colonized by the pathogen's intercellular hyphae. Applications of two cytokinins, benzylaminopurine and meta-topolin, previously shown to suppress B. lactucae sporulation if applied 24 h prior to inoculation at a concentration of 200 microM, retarded the pathogen's asexual reproduction with no apparent negative effects on the host's photosynthetic apparatus. However, long-lasting treatment of healthy tissues with this high concentration of exogenous cytokinin led to effects parallel to pathogenesis: reductions in photosynthetic pigment contents accompanied by inhibition of photosystem II photochemistry and electron transport. These effects of both prolonged exposure to cytokinins and the pathogenesis were weaker in discs exposed to the lower photosynthetic photon flux density. The role of cytokinins in plant-biotrophic pathogen interactions and their potential as disease control agents are discussed.

Histomorphological transformation of the auricular cartilage after carbon dioxide laser-assisted Mustardé otoplasty. An experimental study.

In an experiment on ten rabbits, 8 W carbon dioxide (CO(2)) laser evaporation of the perichondrium, together with one-third to one-half of the thickness of the auricle cartilage, was performed. Subsequently, the auricle was bent in the middle of the vaporized area, the corresponding surfaces of which were then apposed and fixed to each other with mattress sutures. Three months later the auricle specimen was harvested for histopathological evaluation. This revealed that the partially laser-ablated cartilage had grown together in the form of a solid cartilaginous column. The regeneration process, originating from chondroblasts as well as from perichondrium cells, was strongly stimulated by the laser energy delivered.

Suitable conditions for sealing of open dentinal tubules using a pulsed Nd:YAG laser.

UNLABELLED: BACKGROUND DATA AND OBJECTIVES: Nd:YAG laser radiation has been applied in treatment of dentine hypersensitivity; dentine melt created after irradiation on a tooth surface can occlude open dentinal tubules. Different conditions (energy of pulses, number of successive irradiations, and type of dye agent) have been reported in the literature. In our study, different conditions are compared and the most suitable ones are suggested. METHODS: One hundred nine dentine samples prepared from extracted human third molars in the form of 2- or 3-mm thick discs and facets from an outer convex surface of a root were irradiated by pulses with duration 0.3 ms and beam diameter 0.3 or 0.6 mm. The laser repetition rate was 15 Hz. Energies per pulse have been changed from 20 mJ to 250 mJ (the corresponding energy densities rho are 22 and 275 J/cm(2) for the beam diameter of 0.3 mm). Dyes including tartrazine, carmine indigo, erythrosin, and methylene blue have been used to cover dentine surfaces and to increase absorption of laser radiation. Irradiated dentine surfaces have been investigated using scanning electron microscopy. RESULTS: Sealing of open dentinal tubules can be accomplished even without dyes, provided that a sufficiently intense laser radiation level is used. To avoid damage to the dentine's surface the use of dyes is necessary. Erythrosin has been found to be the best agent, and closing of dentinal tubules occurred after four doses of irradiation with 30-mJ pulses with a beam diameter of 0.6 mm (energy density rho = 8.25 J/cm(2), total energy density rho(T) = 33 J/cm(2)). The upper limit has been reached using four doses of irradiation by 90-mJ pulses with a beam diameter of 0.3 mm (rho = 99 J/cm(2), rho(T) = 396 J/cm(2)). CONCLUSIONS: Occluding dentinal tubules can safely and effectively be accomplished using pulsed Nd:YAG laser radiation provided that the dentine surface is covered with erythrosin solution.

Sealing of open dentinal tubules by laser irradiation: AFM and SEM observations of dentine surfaces.

Dentin of human teeth is a vital hydrated tissue. It is strongly sensitive to dehydration and drying that are commonly used in preparation of samples for scanning electron microscopy. Experience in examination of dentine surfaces of extracted human third molars using contact mode atomic force microscopy under moist conditions is described. The examined dentine surfaces are modified by laser radiation produced by a pulsed Nd:YAG laser that leads to sealing of open dentinal tubules under suitable conditions that are reached after covering dentine surfaces with dye agents. Out of four investigated dye agents erythrosin solution in water has been found the most suitable and the lower and upper limits of pulse energies for sealing of dentinal tubules have been set.

Biological aspects of Lyme disease spirochetes: unique bacteria of the Borrelia burgdorferi species group.

BACKGROUND: Borrelia burgdorferi sensu lato is a group of at least twelve closely related species some of which are responsible for Lyme disease, the most frequent zoonosis in Europe and the USA. Many of the biological features of Borrelia are unique in prokaryotes and very interesting not only from the medical viewpoint but also from the view of molecular biology. METHODS: Relevant recent articles were searched using PubMed and Google search tools. RESULTS AND CONCLUSION: This is a review of the biological, genetic and physiological features of the spirochete species group, Borrelia burgdorferi sensu lato. In spite of a lot of recent articles focused on B. burgdorferi sensu lato, many features of Borrelia biology remain obscure. It is one of the main reasons for persisting problems with prevention, diagnosis and therapy of Lyme disease. The aim of the review is to summarize ongoing current knowledge into a lucid and comprehensible form.

Examination of dentin surface using AFM (our experience).

Atomic force microscopy (AFM) as one the technique of Scanning Probe Microscopy is useful for imaging of surface structure. This method can yield three-dimensional high-resolution topographic images of sample surfaces by using a scanning technique for conductors and insulators on atomic scale. It is based upon mapping of atomic-forces on a surface of an investigated sample. The method is useful not only in physics and chemistry; it can be also applied in biological fields. Special construction of AFM scanner enables to follow biological samples in liquid environments. Artifacts caused by dehydration of samples are removed this way. Dentin of human teeth is a vital hydrated tissue. It is strongly sensitive to dehydration and drying that are commonly used in preparation of samples in examinations by Scanning Electron Microscopy (SEM). We describe our experience in examination of dentin surfaces of extracted human third molars using contact method of AFM under moist conditions.

Ultra-structural and functional changes in the chloroplasts of detached barley leaves senescing under dark and light conditions.

Changes in the chloroplast ultra-structure and photochemical function were studied in detached barley (Hordeum vulgare L. cv. Akcent) leaf segments senescing in darkness or in continuous white light of moderate intensity (90 mumol m-2 s-1) for 5 days. A rate of senescence-induced chlorophyll degradation was similar in the dark- and light-senescing segments. The Chl a/b ratio was almost unchanged in the dark-senescing segments, whereas in the light-senescing segments an increase in this ratio was observed indicating a preferential degradation of light-harvesting complexes of photosystem II. A higher level of thylakoid disorganisation (especially of granal membranes) and a very high lipid peroxidation were observed in the light-senescing segments. In spite of these findings, both the maximal and actual photochemical quantum yields of the photosystem II were highly maintained in comparison with the dark-senescing segments.