Resistance and cross-resistance in Staphylococcus spp. strains following prolonged exposure to different antiseptics.

OBJECTIVES: This aim of this study was to evaluate the potential of staphylococci to develop resistance and cross-resistance to antibiotics following exposure to antiseptics. METHODS: The antibiotic susceptibility profile as well as the antiseptic minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were determined for Staphylococcus epidermidis and Staphylococcus aureus clinical isolates and reference strains (methicillin resistant or not) before and after prolonged exposure to low concentrations of two antiseptics, namely chlorhexidine digluconate (CHG) and octenidine dihydrochloride (OCT). RESULTS: Resistance was observed to both tested antiseptics following exposure. CHG exposure led to increased MICs in five of the six tested strains of S. epidermidis and S. aureus and also led to clinically decreased susceptibility to gentamicin in S. aureus ATCC 43300 (MRSA) and to penicillin and tetracycline in S. aureus ATCC 25923 (MSSA). OCT exposure led to an increased MIC only in S. epidermidis ATCC 12228 (MSSE) and also led to a clinically decreased susceptibility to penicillin in S. aureus clinical strain SAL. One strain (MSSE) showed a four-fold increase in the MIC against CHG. Several strains showed a two-fold increase in the MIC against CHG and only one strain (MSSE) against OCT. CONCLUSION: These results support the urgent need to apply the same administration rules currently accepted for antibiotics to antiseptics in order to preserve the benefits both of antiseptics and antibiotics.

Non-Botrytis grape-rotting fungi responsible for earthy and moldy off-flavors and mycotoxins.

The grape microflora is complex and includes filamentous fungi, yeasts and bacteria with different physiological characteristics and effects on wine production. Most studies have focused on the wine microbiota, but a few studies have reported the ecology of grape microorganisms. Some of these organisms - such as non-Botrytis bunch rotting fungi, which greatly influence the safety or sensory quality of wine, due to the production of mycotoxins and off-flavors, respectively - are considered to be spoilage agents. We review here the diversity of filamentous fungi on grapes and the factors influencing their development, such as grape ripening stage, environmental factors (climate, rain and cultivation practices), grape variety and grape health status. We also discuss the pathways by which mycotoxins and off-flavors are produced, the control of the population, the metabolites responsible for wine spoilage and the methods for detecting and characterizing the microorganisms involved.

Development of a qPCR assay for specific quantification of Botrytis cinerea on grapes.

The aim of this study was to develop a system for rapid and accurate real-time quantitative PCR (qPCR) identification and quantification of Botrytis cinerea, one of the major pathogens present on grapes. The intergenic spacer (IGS) region of the nuclear ribosomal DNA was used to specifically detect and quantify B. cinerea. A standard curve was established to quantify this fungus. The qPCR reaction was based on the simultaneous detection of a specific IGS sequence and also contained an internal amplification control to compensate for variations in DNA extraction and the various compounds from grapes that inhibit PCR. In these conditions, the assay had high efficiency (97%), and the limit of detection was estimated to be 6.3 pg DNA (corresponding to 540 spores). Our method was applied to assess the effects of various treatment strategies against Botrytis in the vineyard. Our qPCR assay proved to be rapid, selective and sensitive and may be used to monitor Botrytis infection in vineyards.