Serotypes and virulence profiles of Shiga toxin-producing Escherichia coli strains isolated during 2017 from human infections in Switzerland

Since 2015, the Swiss Federal Office of Public Health registered an increase of notifications of STEC, probably due to the adoption of culture independent stx screening tests in diagnostic laboratories. This study aimed to identify the serotypes and virulence genes of 120 STEC isolated from human clinical stx positive specimens during 2017 in order to estimate any changes in serotype distribution and toxin profiles of STEC compared to the time span 2010-2014. Culturing of STEC from stool samples was achieved using the streak plate technique on MacConkey agar. We performed O and H serotyping by PCR and by micro array. Virulence genes were identified and subtyped using molecular methods, including stx1 and stx2 subtypes, and the intimin encoding gene, eae. STEC were recovered from 27.5% of the stx positive samples. STEC O157:H7 accounted for 7.5% of all isolates, and STEC O80:H2, O91:H10/H14/H21, O103:H2/H11, and O26:H11 accounted for 36.9% of the non-O157 strains. Forty-five isolates with stx1 variants, 47 with stx2 variants and 28 isolates with both stx1 and stx2 variants were identified. Forty (33.3% of all isolates) carried the subtypes associated with high pathogenic potential, stx2a, stx2c, or stx2d. The eae gene for intimin was detected in 54 strains (45% of all strains). Compared to 2010-2014, our data show that the proportion of the so called "top five" serogroups, STEC O26, O111, O103, and O157 declined from 53.7% to 28.3% in 2017. The proportion of isolates with stx2a, stx2c, or stx2d decreased from 50.5% to 33.3%. We also observed an increase of STEC harbouring the low pathogenic subtypes stx2b and stx2e from 12.6% to 29.2%, and of eae negative STEC from 29.5% in 2010-2014 to 55% in 2017. Simultaneously, there was a sharp increase of the patients' median age from 24 years to 46.5 years. Clinical manifestations in the patients included abdominal pain without diarrhea (22.3%), diarrhea (77.7%), and the haemolytic-uremic syndrome (HUS) (7.4%). Our data show that a greater number and a wider range of STEC serotypes are detected by culture-independent testing, with implications for public health services

Wound healing process in post-bariatric patients: an experimental evaluation

Bariatric surgery is the most effective treatment for morbid obesity. Despite this, side effects are recorded. One of them is redundant skin hanging from the patients' body causing both aesthetical and functional deformities. They can only be corrected with body contouring surgery, whose wound complication rate is very high in previously obese population. Despite several hypotheses, an adequate explanation is still awaited. The aim of our study was to evaluate the wound healing process in post-bariatric patients. Seven patients, six women and one man, were enrolled. They all were nonsmokers and nondiabetic. They all underwent biliopancreatic diversion (BPD). After 36 months, abdominoplasty was performed. Biochemical parameters before and after bariatric surgery were evaluated. The content of total protein and hydroxyproline was assessed in multiple scar biopsies before and after BPD. Abdominoplasty horizontal scar skin samples were subjected to histological evaluation with Weigert-Van Gieson stain for elastic fibers and connectivum. All biochemical parameters analyzed were reduced post-BPD compared to the preoperative period. Tissue proteins were significantly reduced after BPD both in their totality and as hydroxyproline and hydroxyproline/total tissue protein. Histological evaluation revealed abnormal dermal elastic and collagen fibers. The cause of aberrant healing in massive weight loss body contouring is likely multifactorial. A relationship between nutritional state, wound collagen accumulation, and elastic fiber content seems to be only partially involved. The high mechanical stress of tissues before BPD probably influences the wound healing process after BPD