Is there a link between shell morphology and parasites of zebra mussels?

The shell morphology of zebra mussels, Dreissena polymorpha, was analyzed to determine if alterations in shell shape and asymmetry between valves were related to its infection status, i.e. infected or not by microparasites like ciliates Ophryoglena spp. or intracellular bacteria Rickettsiales-like organisms (RLOs), and by macroparasites like trematodes Phyllodistomum folium and Bucephalus polymorphus. For microparasites, two groups of mussels were observed depending on shell measurements. Mussels with the more concave shells were the most parasitized by ciliates. This could be more a consequence than a cause and we hypothesized that a modification of the water flow through the mantle cavity could promote the infection with a ciliate. There were more RLOs present in the most symmetrical individuals. A potential explanation involved a canalization of the left-right asymmetry as a by-product of the parasite infection. Trematode infections were associated with different responses in valve width. Females infected by P. folium displayed significantly higher symmetry in valve width compared with non-infected congeners, whereas the infection involved an opposite pattern in males. B. polymorphus was also linked to a decrease in valve width asymmetry. This study suggested that a relationship exists between parasitism and shell morphology through the physiological condition of host zebra mussels.

Study of Small Intestinal Bacterial Overgrowth in a Cohort of Patients with Abdominal Symptoms Who Underwent Bariatric Surgery.

INTRODUCTION: Small intestinal bacterial overgrowth (SIBO) is a common complication of bariatric surgery. Digestive decontamination treatments with oral antibiotic therapy vary and are not codified. This retrospective study was conducted to analyse the characteristics of bariatric surgery patients who underwent a glucose breath test (GBT) and to analyse the effectiveness of the antibiotic decontamination therapy. MATERIALS AND METHODS: A total of 101 operated patients (Roux-en-Y bypass (RYB), omega bypass (ΩB) and sleeve gastrectomy (SG)) who underwent a GBT (75 g/250 mL) were included. Anthropometric data, symptoms of SIBO, type of surgery, use of proton pump inhibitors (PPIs) and antibiotic therapy were analysed. The effectiveness of the antibiotic treatment, defined by improvement of the symptoms, was evaluated during the follow-up. RESULTS: Of the 85 women and 16 men included (48.5 ± 3.6 years old), 63 underwent RYB, 31 underwent ΩB and 7 underwent SG. The GBT was positive in 83% of the patients. A positive test was associated with age (p < 0.001), female sex (p < 0.01) and PPI use (p < 0.01), but there was no significant difference according to the type of surgery. Sixty-one percent of patients treated with gentamicin/metronidazole sequential antibiotic therapy and 58% of patients treated with metronidazole alone achieved treatment efficacy (with no significant difference in efficacy between these treatments). CONCLUSION: SIBO should be systematically considered in the context of abdominal symptoms in bariatric surgery patients, regardless the type of surgery, particularly in patients who are older or female and after PPI treatment. Digestive decontamination appears to be similar between gentamycin/metronidazole and metronidazole treatments.