The biofilm architecture of sixty opportunistic pathogens deciphered using a high throughput CLSM method

This study proposes a high throughput method based on Confocal Laser Scanning Microscopy (CLSM) combined with the use of 96-wells microtiter plates compatible with high resolution imaging for the study of biofilm formation and structure. As an illustration, the three-dimensional structures of biofilms formed by 60 opportunistic pathogens were thus observed and quantified. The results revealed the diversity of biofilm architectures. Specific spatial arrangement such as the mushroom-like structures already described for Pseudomonas aeruginosa was observed. Other features, such as hollow voids in microcolonies of Salmonella enterica strain Agona, were identified for the first time. The combined use of microplates and confocal imaging proved to be a good alternative to the other high throughput methods commonly used as it enables the direct, insitu, qualitative and quantitative characterization of biofilm architecture. This high content method should lead to a clearer understanding of the structure-function relationships implicated in biofilms traits.

Patient and public involvement in clinical guidelines: international experiences and future perspectives

BACKGROUND

Clinical practice guidelines (CPG) are important tools for improving patient care. Patient and public involvement is recognised as an essential component of CPG development and implementation. The Guideline International Network Patient and Public Involvement Working Group (G-I-N PUBLIC) aims to support the development, implementation and evaluation of guideline-oriented patient and public involvement programmes (PPIPs).

OBJECTIVE

To develop an international practice and research agenda on patient and public involvement in CPG.

METHOD

56 CPG developers, researchers, and patient/public representatives from 14 different countries, were consulted in an international workshop. Recommendations were validated with G-I-N PUBLIC steering committee members.

RESULTS

Many CPG organisations have set up PPIPs that use a range of participation, consultation and communication methods. Current PPIPs aim to improve the quality and responsiveness of CPGs to public expectations and needs, or to foster individual healthcare decisions. Some organisations use structured involvement methods, including providing training for patient and public representatives. A number of financial, organisational and sociopolitical barriers limit patient and public involvement. The paucity of process and impact evaluations limits our current understanding of the conditions under which patient and public involvement is most likely to be effective.

CONCLUSION

Greater international collaboration and research are needed to strengthen existing knowledge, development and evaluation of patient and public involvement in CPG.

Using mental imagery and visualisation with cancer patients

Mental imagery and visualisation are techniques that can help cancer patients manage their responses to the illness and help them mobilise inner psychological resources.

Perforated appendicitis presenting with ileo-caecal ulceration and mechanical intestinal obstruction

A 30-year-old lady presented with a 6-month history of recurrent partial intestinal obstruction associated with intermittent fever, anorexia and weight loss. Barium meal follow-through and colonoscopic evaluation suggested ulceration of the ileum and caecum with small bowel obstruction. Histology of the lesions showed marked acute and chronic inflammation consistent with ulceration and granulation tissue. Abdominal CT revealed circumferential thickening of the ascending colon, caecum and terminal ileum with extraluminal air pockets. Surgical exploration revealed a large conglomerate mass involving the terminal ileum, caecum and ascending colon. Histopathology of the resected specimen revealed perforated appendix with nonspecific ulceration of the surrounding bowel. She recovered completely after surgery and did not suffer from gastrointestinal symptoms in the 14 months of follow-up.

Amoebae-resisting bacteria in drinking water: risk assessment and management

Free-living amoebae have been detected in a large number of man-made water systems, including drinking water distribution systems. Some of these amoebae can host amoebae-resisting bacteria, and thus act potentially as reservoirs and vehicles for a number of pathogens. The objectives of this study were to characterize the amoebae and amoebae-resisting bacteria present in different raw waters used for drinking water production, and to assess the efficiency of different treatments applied for drinking water production in removing or inactivating these amoebae. The preliminary results of this study confirm the presence of amoebae and amoebae-resisting bacteria in raw waters used for drinking water production. Due to their capacity to encyst, most of these amoebae are extremely resistant to disinfection processes. In these conditions, preventing the dissemination of these micro-organisms through drinking water will mainly require their physical removal by clarification and filtration processes. The particular hazard that amoebae-resisting bacteria represent in drinking water production should be taken into account in any risk assessment conducted in the framework of a water safety plan, and control strategies based on physical removal rather than disinfection should be adopted where necessary.

Relationship between mycobacteria and amoebae: ecological and epidemiological concerns

Since the discovery that Legionella pneumophila can survive and grow within free-living amoebae, there has been an increasing number of microbial species shown to have similar relationships. These include many bacterial species, fungi, other protozoa (e.g. Cryptosporidium) and viruses. Among bacteria, mycobacteria are of particular importance because of their role in human and animal infections. This review will consider the progress made in understanding the relationships between mycobacteria and amoebae, and their consequences in terms of ecology and epidemiology.

A versatile strategy to fabricate hydrogel–silver nanocomposites and investigation of their antimicrobial activity

In this study, hydrogel-silver nanocomposites have been synthesized by a unique methodology, which involves formation of silver nanoparticles within swollen poly (acrylamide-co-acrylic acid) hydrogels. The formation of silver nanoparticles was confirmed by transmission electron microscopy (TEM) and surface plasmon resonance (SPR) which was obtained at 406 nm. The TEM of hydrogel-silver nanocomposites showed almost uniform distribution of nanoparticles throughout the gel networks. Most of the particles, as revealed from the particle-size distribution curve, were 24-30 nm in size. The X-ray diffraction pattern also confirmed the face centered cubic (fcc) structure of silver nanoparticles. The nanocomposites demonstrated excellent antibacterial effects on Escherichia coli (E. coli). The antibacterial activity depended on size of the nanocomposites, amount of silver nanoparticles, and amount of monomer acid present within the hydrogel-silver nanocomposites. It was also found that immersion of plain hydrogel in 20 mg/30 ml AgNO(3) solution yielded nanocomparticle-hydrogel composites with optimum bactericidal activity.

A role for tissue transglutaminase in alpha-gliadin peptide cytotoxicity

In coeliac disease, gliadin peptides p56-88, p57-68 and p31-49 have been demonstrated to be involved in the pathogenic damage of the small intestine via their immunogenicity or toxicity to epithelial cells. To try to understand the mechanism of their toxicity, we investigated the effect of synthetic peptides (p31-49, p56-88, p57-68, p69-82) and of their deamidated analogues on Caco2 and FHs 74 Int cell toxicity and tissue tranglutaminase activity. Apoptosis, necrosis and cell viability were assessed by flow cytometry, and peptide deamidation was determined indirectly by measuring its capacity to inhibit tTG activity. The results showed that p56-88 and p57-68 reduced cell growth and concomitantly inhibited tTG activity in both cell types. This effect was abolished when Caco2 cells were treated with antibodies to tTG. Deamidated peptide p57-68 (E(65)) lost practically all of its inhibitory effect on cell growth and on tTG activity. Cellular toxicity was also observed with p31-49, which was not a substrate for tTG. p69-82 was not cytotoxic but became so when glutamine 72 was substituted by glutamic acid. These findings provide evidence for the existence of three types of toxicity among gliadin peptides: (i) peptides that are intrinsically toxic and are not substrates of tTG; (ii) peptides that are non-toxic but become so when they act as substrates of tTG; and (iii) peptides that are non-toxic and are not substrates of tTG but become so when deamidated. A mechanism other than that involving tTG could be responsible for the deamidation of glutamine residues of gliadin in the intestinal tract.