Identification of a multidrug efflux pump in Flavobacterium johnsoniae

In this study, the mechanism conferring multiple drug resistance in several strains of flavobacteria isolated from the ovarian fluids of hatchery reared 3-year old brook trout Salvelinus fontinalis was investigated. Metabolic fingerprinting and 16S rRNA gene sequences identified the isolates as Flavobacterium johnsoniae. The isolates exhibited multiple resistances to a wide range of antimicrobial classes including penicillin, cephem, monobactam, aminoglycoside, and phenicol. Although plasmids and other transposable elements containing antimicrobial resistance genes were not detected, the isolates did contain a genomic sequence for a chloramphenicol-inducible resistance-nodulation-division family multidrug efflux pump system. Efflux pumps are non-specific multidrug efflux systems. They are also a component of cell-cell communication systems, and respond specifically to cell membrane stressors such as oxidative or nitrosative stress. Understanding of efflux pump mediated antibiotic resistances will affect efficacy of clinical treatments of fishes associated with F. johnsoniae epizootics.     

The effects analysis of two neonicotinoid insecticides on in vitro maturation of porcine oocytes using hanging drop monoculture method

Acetamiprid (ACE) and imidacroprid (IMI) are known neonicotinoid insecticides with strong affinities for the insect-selective nicotinic acetylcholine receptor. These provide insect control by hyperstimulating insect nerves and are used for agricultural pest management. However, it has also been reported that ACE and IMI affect mammalian reproductive function. We determined the effects of ACE and IMI on the in vitro maturation of porcine oocytes. Significant decreases in nuclear maturation rates were observed in the ACE or IMI-exposed groups. Also, in matured oocytes from the ACE or IMI-exposed groups, irregular chromosomes were observed. Our results suggest that ACE and IMI exposure was detrimental to porcine oocytes and the extent of the effects depends on the concentration of exposure.     

Experimental in vitro transmission of Babesia sp. (EU1) by Ixodes ricinus

Babesia sp. (EU1), first characterized in 2003, has been implicated in human cases of babesiosis in Italy, Austria and Germany. It has been identified in roe deer and in its suspected tick vector, Ixodes ricinus, in several European countries. The aim of the present study was to validate the competence of I. ricinus as a vector of Babesia sp. (EU1) via experimental infections. For this purpose, a parasite strain isolated from roe deer was cloned in sheep erythrocytes. After experimental infections, parasite DNA was successfully amplified by PCR in both eggs and larvae originating from infected I. ricinus females and in the salivary glands of females exposed to Babesia sp. (EU1) as nymphs. We also demonstrate that infected females were able to transmit parasite DNA during a new blood meal. Together with previous epidemiological studies, these results validate I. ricinus as a competent vector for Babesia sp. (EU1).