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Valat C.,Unite Antibioresistance et Virulence Bacteriennes | Haenni M.,Unite Antibioresistance et Virulence Bacteriennes | Saras E.,Unite Antibioresistance et Virulence Bacteriennes | Auvray F.,Anses Laboratoire Of Securite Des Aliments Of Maisons Alfort | And 2 more authors.
Applied and Environmental Microbiology

We report the discovery of a CTX-M-15-producing Escherichia coli (STEC) of serogroup O111:H8, a major serotype responsible for human enterohemorrhagic Escherichia coli (EHEC) infections. In line with the recent CTX-M-15/O104:H4 E. coli outbreak, these data may reflect an accelerating spread of resistance to expanded-spectrum cephalosporins within the E. coli population, including STEC isolates. © 2012, American Society for Microbiology. Source

Valat C.,Unite Antibioresistance et Virulence Bacteriennes | Auvray F.,Anses Laboratoire Of Securite Des Aliments Of Maisons Alfort | Forest K.,Unite Antibioresistance et Virulence Bacteriennes | Metayer V.,Unite Antibioresistance et Virulence Bacteriennes | And 4 more authors.
Applied and Environmental Microbiology

In line with recent reports of extended-spectrum beta-lactamases (ESBLs) in Escherichia coli isolates of highly virulent serotypes, such as O104:H4, we investigated the distribution of phylogroups (A, B1, B2, D) and virulence factor (VF)-encoding genes in 204 ESBL-producing E. coli isolates from diarrheic cattle. ESBL genes, VFs, and phylogroups were identified by PCR and a commercial DNA array (Alere, France). ESBL genes belonged mostly to the CTX-M-1 (65.7%) and CTX-M-9 (27.0%) groups, whereas those of the CTX-M-2 and TEM groups were much less represented (3.9% and 3.4%, respectively). One ESBL isolate was stx1 and eae positive and belonged to a major enterohemorrhagic E. coli (EHEC) serotype (O111:H8). Two other isolates were eae positive but stx negative; one of these had serotype O26:H11. ESBL isolates belonged mainly to phylogroup A (55.4%) and, to lesser extents, to phylogroups D (25.5%) and B1 (15.6%), whereas B2 strains were quasi-absent (1/204). The number of VFs was significantly higher in phylogroup B1 than in phylogroups A (P=0.04) and D (P=0.02). Almost all of the VFs detected were found in CTX-M-1 isolates, whereas only 64.3% and 33.3% of them were found in CTX-M-9 and CTX-M-2 isolates, respectively. These results indicated that the widespread dissemination of the blaCTX-M genes within the E. coli population from cattle still spared the subpopulation of EHEC/Shiga-toxigenic E. coli (STEC) isolates. In contrast to other reports on non-ESBL-producing isolates from domestic animals, B1 was not the main phylogroup identified. However, B1 was found to be the most virulent phylogroup, suggesting host-specific distribution of virulence determinants among phylogenetic groups. © 2012, American Society for Microbiology. Source

Sotton B.,French National Institute for Agricultural Research | Anneville O.,French National Institute for Agricultural Research | Cadel-Six S.,Anses Laboratoire Of Securite Des Aliments Of Maisons Alfort | Domaizon I.,French National Institute for Agricultural Research | And 2 more authors.
Harmful Algae

Lake Bourget (France) provides drinking water and is a place for professional and recreational fishing. Since the mid 1990s, the lake has been exhibiting blooms of the filamentous cyanobacterium Planktothrix rubescens. This species is able to produce microcystin-LR and RR, toxins that contaminate different fish tissues and, if concentrated in the liver, can induce fish mortality. However, data on fish exposure to these toxins in a natural environment are scare and comparisons of spatial distribution between P. rubescens and exploited fish are needed to determine whether these fish avoid or converge in zones affected by the cyanobacteria. From June to November 2009, diurnal data on P. rubescens and whitefish (Coregonus lavaretus) spatial distributions have been monitored by hydroacoustic and BBE probe sampling. For all water samples, intracellular microcystin concentration of P. rubescens was quantified by HPLC/PDA. Furthermore, an arbitrary sample of eight whitefish captured at the moment of highest P. rubescens concentration in the lake were analyzed to investigate both the presence of this cyanobacterium in the gastrointestinal tract by optical microscopy and the possible bioaccumulation of the microcystin in their tissues by liquid chromatography-tandem mass spectrometry. Results show that P. rubescens abundance was at a maximum between the end of July and the beginning of September. During this period, P. rubescens abundance was vertically stratified with a maximum around 14-22. m, depending on the sampling station. The horizontal distributions of P. rubescens were heterogeneous at the scale of the lake. Results indicate that the presence of P. rubescens, for the observed cyanobacterial abundance, does not exert a significant pressure on the distribution pattern of the whitefish. Whitefish were present in the same areas as P. rubescens maxima during daytime, and they do not avoid or seek out the zone of high P. rubescens abundance. Filaments of P. rubescens have been observed in intestinal tracts of whitefish and the presence of microcystin-LR has been detected in their intestine and liver. Consequently, because of a direct contact between these organisms, toxins can be incorporated into whitefish by ingestion of P. rubescens filaments, leading to potential adverse effects on the health of this species. © 2011 Elsevier B.V. Source

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