Epidemiology of esophageal atresia

Esophageal atresia (EA) is a rare congenital malformation consisting of a lack of continuity between the upper and lower esophageal pouches, frequently associated with tracheoesophageal fistula. The prevalence of such rare abnormalities is established by global birth surveillance programs over the world. EUROCAT is a European program covering 1.7 million births since its creation. The prevalence of EA in Europe seems stable over decades. The National Birth Defects Prevention Network in the USA also shows a stable prevalence with a wide range between states or regions. In France, with the implementation of the national rare diseases plan, a reference center for congenital abnormalities of the esophagus was created in 2006 and a national registry for EA began patient inclusion in 2008. This has resulted in the establishment of the national live birth prevalence for EA, prenatal diagnosis rates, and clinical characteristics of EA patients, early survival, and early morbidity. Prevalence rates seem stable all over the world since many decades. Continuous surveillance of congenital abnormalities and specific registries are useful for epidemiologic data but also for public health authorities for helping families of rare diseases patients.

Esophageal atresia: metaplasia, Barrett

Barrett's esophagus is characterized by the replacement of squamous epithelium by columnar epithelium that is intestinal metaplasia-positive or -negative in the distal esophagus. Gastroesophageal reflux disease, which is frequent and prolonged in esophageal atresia, probably plays a major role in the development of Barrett's esophagus through repeated mucosal damage. Long-term acid exposure contributes to carcinogenesis in Barrett's esophagus of intestinal type, but its effect on gastric metaplasia is less well defined. Recent studies have suggest that metaplasia arises in about 15% of patients with esophageal atresia, with a lag time to developing metaplasia from initial surgical correction of about 10 years. Preliminary data from an ongoing multicenter study including 88 patients with esophageal atresia aged 15-19 years showed gastric metaplasia in 42% of patients (29 fundic and 7 cardial metaplasia), while one patient presented intestinal metaplasia. Esophageal mucosal abnormalities can be observed in esophageal atresia patients at endoscopy despite the absence of symptoms. Whether prolonged, aggressive, acid suppression is beneficial in these situations remains to be determined. Barrett's metaplasia can be removed by endoscopic mucosal resection or destroyed with endoscopic ablative techniques, such as photodynamic therapy, radiofrequency ablation, and cryotherapy. The risk of developing esophageal carcinoma is still a controversial issue as only a few clinical cases have been reported in young adults with esophageal atresia. As late complications of esophageal atresia, particularly esophagitis and Barrett's esophagus, are increasingly being recognized, long-time systematic follow up of the esophageal mucosa including multistage biopsies is therefore required even in asymptomatic patients.

Response of bacterial isolates from Antarctic shallow sediments towards heavy metals, antibiotics and polychlorinated biphenyls

The response of bacterial isolates from Antarctic sediments to polychlorinated biphenyls (Aroclor 1242 mixture), heavy metal salts (cadmium, copper, mercury and zinc) and antibiotics (ampicillin, chloramphenicol, kanamycin and streptomycin) was investigated. Overall, the ability to growth in the presence of Aroclor 1242 as a sole carbon source was observed for 22 isolates that mainly belonged to Psychrobacter spp. Tolerance to the heavy metals assayed in this study was in the order of Cd > Cu > Zn > Hg and appeared to be strictly related to the metal concentrations, as determined during previous chemical surveys in the same area. With regards to antibiotic assays, the response of the isolates to the tested antibiotics ranged from complete resistance to total susceptibility. In particular, resistances to ampicillin and chloramphenicol were very pronounced in the majority of isolates. Our isolates differently responded to the presence of toxic compounds primarily based on their phylogenetic affiliation and secondarily at strain level. Moreover, the high incidence of resistance either to metal or antibiotics, in addition to the capability to grow on PCBs, confirm that bacteria are able to cope and/or adapt to the occurrence pollutants even in low human-impacted environments.

Partaking of Archaea to biogeochemical cycling in oxygen-deficient zones of meromictic saline Lake Faro (Messina, Italy)

We used a combination of molecular and microbiological approaches to determine the activity, abundance and diversity of archaeal populations inhabiting meromictic saline Lake Faro (Messina, Italy). Analysis of archaeal 16S rRNA, amoA, accA and hbd genes and transcripts revealed that sub- and anoxic layers of Lake Faro are primarily inhabited by the organisms related to the clusters of Marine Group I.1a of Thaumarchaeota frequently recovered from oxygen-depleted marine ecosystems. These organisms dominated the metabolically active archaea down to the bottom of the lake, indicating their adaptation to recurrent changes in the levels of water column hypoxia. The upper microaerobic layer of Lake Faro redoxcline has the maximal rates of dark primary production much lower than those of other previously studied pelagic redoxclines, but comparable to the values of meso- and bathypelagic areas of Mediterranean Sea. Application of bacterial inhibitors, especially azide, significantly declined the CO2 fixation rates in the low interface and monimolimnion, whereas archaea-specific inhibitor had effect only in upper part of the redoxcline. Based on these findings, we hypothesize that dark bicarbonate fixation in suboxic zone of Lake Faro results mainly from archaeal activity which is affected by the predicted lack in oxygen in lower layers.

[Current indications of ileocolonoscopy in children in 2012]

Les indications de l’iléo-coloscopie chez l’enfant ont été définies en 2002 par le Groupe francophone d’hépatologie gastroentérologie et nutrition. Ces recommandations sont mises à jour sous l’éclairage des nouvelles données et avancées technologiques de la dernière décennie. L’iléo-coloscopie reste essentiellement indiquée devant les hémorragies digestives (méléna ou rectorragies, anémie) et les suspicions de maladie inflammatoire chronique intestinale (MICI). Elle est désormais indiquée pour contrôler l’évolution des MICI, notamment pour contrôler la cicatrisation muqueuse sous traitement et l’absence de récidive postopératoire. Les indications d’iléo-coloscopie itérative sont surtout représentées par les polyposes génétiques avec des recommandations validées pour la polypose adénomateuse familiale. Les contre-indications n’ont pas été modifiées.

Marine bacterioplankton diversity and community composition in an antarctic coastal environment

The bacterial community inhabiting the water column at Terra Nova Bay (Ross Sea, Antarctica) was examined by the fluorescent in situ hybridization (FISH) technique and the genotypic and phenotypic characterization of 606 bacterial isolates. Overall, the FISH analysis revealed a bacterioplankton composition that was typical of Antarctic marine environments with the Cytophaga/Flavobacter (CF) group of Bacteroidetes that was equally dominant with the Actinobacteria and Gammaproteobacteria. As sampling was performed during the decay of sea-ice, it is plausible to assume the origin of Bacteroidetes from the sea-ice compartment where they probably thrive in high concentration of DOM which is efficiently remineralized to inorganic nutrients. This finding was supported by the isolation of Gelidibacter, Polaribacter, and Psychroflexus members (generally well represented in Antarctic sea-ice) which showed the ability to hydrolyze macromolecules, probably through the production of extracellular enzymes. A consistently pronounced abundance of the Gammaproteobacteria (67.8%) was also detected within the cultivable fraction. Altogether, the genera Psychromonas and Pseudoalteromonas accounted for 65.4% of total isolates and were ubiquitous, thus suggesting that they may play a key role within the analyzed bacterioplankton community. In particular, Pseudoalteromonas isolates possessed nitrate reductase and were able to hydrolyze substrates for protease, esterase, and β-galactosidase, thus indicating their involvement in the carbon and nitrogen cycling. Finally, the obtained results highlight the ability of the Actinobacteria to survive and proliferate in the Terra Nova Bay seawater as they generally showed a wide range of salt tolerance and appeared to be particularly competitive with strictly marine bacteria by better utilizing supplied carbon sources.

Characterization of the volatile profile of Antarctic bacteria by using solid-phase microextraction-gas chromatography-mass spectrometry

Bacteria belonging to the Burkholderia cepacia complex (Bcc) are significant pathogens in Cystic Fibrosis (CF) patients and are resistant to a plethora of antibiotics. In this context, microorganisms from Antarctica are interesting because they produce antimicrobial compounds inhibiting the growth of other bacteria. This is particularly true for bacteria isolated from Antarctic sponges. The aim of this work was to characterize a set of Antarctic bacteria for their ability to produce new natural drugs that could be exploited in the control of infections in CF patients by Bcc bacteria. Hence, 11 bacterial strains allocated to different genera (e.g., Pseudoalteromonas, Arthrobacter and Psychrobacter) were tested for their ability to inhibit the growth of 21 Bcc strains and some other human pathogens. All these bacteria completely inhibited the growth of most, if not all, Bcc strains, suggesting a highly specific activity toward Bcc strains. Experimental evidences showed that the antimicrobial compounds are small volatile organic compounds, and are constitutively produced via an unknown pathway. The microbial volatile profile was obtained by SPME-GC-MS within the m/z interval of 40-450. Solid phase micro extraction technique affords the possibility to extract the volatile compounds in head space with a minimal sample perturbation. Principal component analysis and successive cluster discriminant analysis was applied to evaluate the relationships among the volatile organic compounds with the aim of classifying the microorganisms by their volatile profile. These data highlight the potentiality of Antarctic bacteria as novel sources of antibacterial substances to face Bcc infections in CF patients.