Fifty-five Escherichia coli strains belonging to enteropathogenic E. coli (EPEC) serogroups were examined for phenotypic and genetic factors associated with virulence. The strains were isolated in Italy from children with diarrhea and identified as EPEC by clinical laboratories using commercially available antisera. O:H serotyping showed that 35 strains (27 of O26, O111, and O128 serogroups) belonged to 11 serotypes considered to be classical EPEC O:H serotypes. The other 20 isolates were classified as 15 nonclassical EPEC O:H serotypes. All the potential EPEC virulence factors associated with bacterial adhesion (localized adherence, fluorescentactin staining test positivity, presence of the attaching and effacing [eaeA] gene), the production of verotoxin, and the positivity with the enterohemorrhagic E. coli probe were significantly more frequent among isolates belonging to classical than nonclassical serotypes. Strains displaying an aggregative adhesion and hybridizing with the enteroaggregative DNA probe were found in serogroups O86, O111, and O126. Verotoxin-producing isolates belonged to serogroups O26, O111, and O128. Only one of the isolates hybridized with the EPEC adherence factor (EAF) probe, but 33 strains gave positive results with the eae probe, confirming that the former is more suitable in epidemiological studies in European countries. These results indicate that up to 75% of strains identified as EPEC by commercial antisera may possess potential virulence properties and/or belong to classical EPEC O:H serotypes and suggest that O grouping is still a useful diagnostic tool for presumptive identification of diarrheagenic E. coli in clinical laboratories.
Recent therapeutic approaches have improved the prognosis of children with HIV. Many new efforts could be involved in their quality of life and therefore could need additional diagnostic strategies. Leptin regulates pubertal development; furthermore a continuous immune stimulus, as in chronic infectious diseases, can enhance leptin's secretion by the action of cytokines such as interleukin (IL)-6. To clarify this role in patients infected with HIV, we assayed leptin and IL-6 and evaluated the influence of HIV severity on its secretion. IL-6 (380.5 +/- 257.6 pg/ml; range: 22-900 pg/ml) showed a significant correlation with leptinemia, HIV-1 RNA, and viremia related to the stage of HIV disease. The difference in leptinemia from a control group (3 +/- 3.2 ng/ml; range: 1-12 ng/ml in HIV patients; 6.72 +/- 8 ng/ml in the controls) did not reach statistical significance, nor did it correlate with pubertal stage, BMI, viremia, CD4 or anti-retroviral therapy. There was a statistically significant correlation between leptinemia and the stage of the HIV disease, and with IL-6 level. We want to stress the role of immunological factors in enhancing leptin secretion.
Coeliac disease, daily more frequently diagnosed in our population, involves many organs also in oligosymptomatic patients and with an adequate nutritional regime. Possible endocrine implications include failure to thrive, pubertal delay and reproduction diseases due to deregulation of GH, FSH and LH secretion. Leptin, an adipose tissue hormone, can be decreased as well and its deficiency could be related to growth and puberty anomalies. We studied 14 asymptomatic coeliac patients in peripubertal age (7.5–13.8 years) and tested their leptin levels in order to correlate them with endocrine and anthropometric data. Before the diet was started leptinaemia (M±DS) was: 4.94 ± 5.53 ng/ml. In 10/14 patients (71%) leptinaemia was ≤2 DS for gender and age. In all the patients, after a period of 6–12 months of gluten-free diet, Leptin levels appreciably raised to 10.8 ± 7.9 ng/ml, with a significant correlation to the time of the diet. Leptinaemia was actually lower in patients with a severe mucosal atrophy, and in these patients it increased more significantly after the diet was started. The removal of gluten itself may reduce immunological hit to adipose tissue and the ‘malnutrition’ of adipocytes: leptin can hence increase despite no significant increase of body mass index occurs. This study could partially explain the correlation between body mass index, Coeliac disease and the deregulation of puberty and fertility, mainly in patients who started the diet late. It could also explain the reversibility of this alteration if the cause is removed.
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