High Prevalence of OXA-23 Carbapenemase-Producing Proteus mirabilis among Amoxicillin-Clavulanate-Resistant Isolates in France.

In this multicentric study performed in 12 French hospitals, we reported that 26.9% (14/52) of the amoxicillin-clavulanate-resistant Proteus mirabilis isolates produced the OXA-23 carbapenemase. We found that an inhibition zone diameter of <11 mm around the amoxicillin-clavulanate disc was an accurate screening cutoff to detect these OXA-23 producers. We confirmed by whole-genome sequencing that these OXA-23-producers all belonged to the same lineage that has been demonstrated to disseminate OXA-23 or OXA-58 in P. mirabilis.

Sporocadaceae, a family of coelomycetous fungi with appendage-bearing conidia.

Species of Sporocadaceae are endophytic, plant pathogenic or saprobic, and associated with a wide range of host plants. Recent molecular studies that have attempted to address familial and generic boundaries of fungi belonging to Sporocadaceae were based on a limited number of samples and DNA loci. The taxonomy of this group of fungi is therefore still not fully resolved. The aim of the present study is to provide a natural classification for the Sporocadaceae based on multi-locus phylogenetic analyses, using LSU, ITS, tef-1α, tub2 and rpb2 loci, in combination with morphological data. A total of 30 well-supported monophyletic clades in Sporocadaceae are recognised, representing 23 known and seven new genera. Typifications are proposed for the type species of five genera (Diploceras, Discosia, Monochaetia, Sporocadus and Truncatella) to stabilise the application of these names. Furthermore, Neotruncatella and Dyrithiopsis are synonymised under Hymenopleella, and the generic circumscriptions of Diploceras, Disaeta, Hymenopleella, Monochaetia, Morinia, Pseudopestalotiopsis, Sarcostroma, Seimatosporium, Synnemapestaloides and Truncatella are emended. A total of 51 new species, one nomina nova and 15 combinations are introduced.

Coelomycetous Dothideomycetes with emphasis on the families Cucurbitariaceae and Didymellaceae.

The taxonomy of the coelomycetes has undergone dramatic changes in recent years, but remains controversial due to the high number of taxa involved, their poor morphological differentiation, the rare occurrence of the sexual morphs, and rapid loss of fertility in vitro. In the present study, we revisited the families Cucurbitariaceae and Didymellaceae (Pleosporales, Dothideomycetes), which include numerous plant pathogens, endophytic species associated with a wide host range, and saprobes. The taxonomy of two of the most relevant genera, i.e. Phoma and Pyrenochaeta, remains ambiguous after several phylogenetic studies, and needs further revision. We have studied a total of 143 strains of coelomycetes from clinical or environmental origin, by combining the LSU, ITS, tub2 and rpb2 sequences for a multi-locus analysis and a detailed morphological comparison. The resulting phylogenetic tree revealed that some fungi previously considered as members of Cucurbitariaceae represented five different families, and four of them, Neopyrenochaetaceae, Parapyrenochaetaceae, Pseudopyrenochaetaceae and Pyrenochaetopsidaceae, are proposed here as new. Furthermore, 13 new genera, 28 new species, and 20 new combinations are proposed within the Pleosporineae. Moreover, four new typifications are introduced to stabilise the taxonomy of these fungi.

Screening of wheat endophytes as biological control agents against Fusarium head blight using two different in vitro tests.

In order to find biological control agents (BCAs) for the management of Fusarium head blight (FHB), a major disease on wheat crops worldwide, 86 microorganisms isolated from inner tissues of wheat plants were discriminated for their ability to inhibit the growth of Fusarium graminearum and Fusarium culmorum by in vitro dual culture assays. A group of 22 strains appeared very effective to inhibit F. graminearum (inhibition of 30-51%) and they were also globally effective in controlling F. culmorum (inhibition of 15-53%). Further evaluation of a subselection of strains by screening on detached spikelets in vitro confirmed three species, namely Phoma glomerata, Aureobasidium proteae and Sarocladium kiliense, that have not yet been reported for their efficacy against Fusarium spp., indicating that looking for BCAs toward FHB among wheat endophytes proved to be promising. The efficacy of some strains turned out different between both in vitro screening approaches, raising the importance of finding the most appropriate screening approach for the search of BCAs. This study pointed out the interest of the test on detached wheat spikelets that provided information about a potential pathogenicity, the growth capacity and efficacy of the endophyte strains on the targeted plant, before testing them on whole plants.