Wolbachia induces strong cytoplasmic incompatibility in the predatory bug Macrolophus pygmaeus.

Macrolophus pygmaeus is a heteropteran predator that is widely used in European glasshouses for the biological control of whiteflies, aphids, thrips and spider mites. We have demonstrated that the insect is infected with the endosymbiotic bacterium Wolbachia pipientis. Several gene fragments of the endosymbiont were sequenced and subsequently used for phylogenetic analysis, revealing that it belongs to the Wolbachia supergroup B. The endosymbiont was visualized within the ovarioles using immunolocalization. Tetracycline treatments were used to cure M. pygmaeus from its infection. Although a completely cured line could not be obtained by this approach, the application of a constant antibiotic pressure over 13 generations resulted in a line with a significantly reduced Wolbachia concentration. Crosses performed with this tetracycline-treated line revealed that the endosymbiont causes severe cytoplasmic incompatibility. This is the first report of a reproductive effect induced by Wolbachia in an economically important heteropteran predator that may have vital implications for its commercial production and use in biological control.

The diagnosis of Clostridium difficile-associated diarrhea: comparison of Triage C. difficile panel, EIA for Tox A/B and cytotoxin assays.

This study prospectively compared; Triage(R) C. difficile test (TCT), TechLab C. difficile toxin A-B enzyme immuno-assay (EIA), and cell-culture cytotoxin test (CT). Of the 400 stools tested, 99 were positive by any test with 92, 41 and 58 detected by TCT, EIA and CT, respectively. Culture of discordant samples indicated that 52 contained C. difficile (42 toxigenic, 10 non-toxigenic), 10 contained Clostridium species and 2 had no detectable clostridium isolates. There were 21/42 toxigenic C. difficile isolates from 17 patients whose stools were negative when originally tested by CT. Review of available patient charts indicated that 12/14 did not previously or currently have C. difficile associated diarrhea, whereas 2 patients developed disease within a few days. Compared to CT as the gold standard, the sensitivity and specificity were; 93%, 89% and 66%, 99% for TCT and EIA respectively. The 8 stool samples with Toxin A(-) Toxin B(+) isolates were detected in 8, 4, and 6 samples by TCT, EIA and CT, respectively. In summary, TCT as a screening test allowed reliable reporting for 85% of stools on the day of receipt. For the 15% of stools requiring further testing we recommend the use of CT.