Malachite green pre‐enrichment medium for improved salmonella isolation from heavily contaminated samples

Schothorst, M. van; Renaud, Annemarie

doi:10.1111/j.1365-2672.1985.tb01783.x

Cited by 35 publications

(15 citation statements)

References 12 publications

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“…Bacillus sp. LD003 did not grow on plates containing MG (not shown), which can probably be attributed to its antimicrobial properties that are particularly effective against Gram-positive microorganisms [39]. As observed for lignin utilization, addition of YE was necessary for dye decolourization by Bacillus sp.…”

Section: Resultsmentioning

confidence: 99%

Isolation and characterization of novel bacterial strains exhibiting ligninolytic potential

et al. 2011

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BackgroundTo expand on the range of products which can be obtained from lignocellulosic biomass, the lignin component should be utilized as feedstock for value-added chemicals such as substituted aromatics, instead of being incinerated for heat and energy. Enzymes could provide an effective means for lignin depolymerization into products of interest. In this study, soil bacteria were isolated by enrichment on Kraft lignin and evaluated for their ligninolytic potential as a source of novel enzymes for waste lignin valorization.ResultsBased on 16S rRNA gene sequencing and phenotypic characterization, the organisms were identified as Pandoraea norimbergensis LD001, Pseudomonas sp LD002 and Bacillus sp LD003. The ligninolytic capability of each of these isolates was assessed by growth on high-molecular weight and low-molecular weight lignin fractions, utilization of lignin-associated aromatic monomers and degradation of ligninolytic indicator dyes. Pandoraea norimbergensis LD001 and Pseudomonas sp. LD002 exhibited best growth on lignin fractions, but limited dye-decolourizing capacity. Bacillus sp. LD003, however, showed least efficient growth on lignin fractions but extensive dye-decolourizing capacity, with a particular preference for the recalcitrant phenothiazine dye class (Azure B, Methylene Blue and Toluidene Blue O).ConclusionsBacillus sp. LD003 was selected as a promising source of novel types of ligninolytic enzymes. Our observations suggested that lignin mineralization and depolymerization are separate events which place additional challenges on the screening of ligninolytic microorganisms for specific ligninolytic enzymes.

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Section: Resultsmentioning

confidence: 99%

Isolation and characterization of novel bacterial strains exhibiting ligninolytic potential

et al. 2011

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“…Rappaport-Vassiliadis soy broth (RVS) has also been used as enrichment media for the selection of Salmonella spp. (Van Schothorst and Renaud, 1985). Selective medium is more specific than non-selective medium to prevent the growth of non-target bacteria and to reduce the impact of competitor microorganisms on the growth of target bacteria (Kim and Bhunia, 2008; Taskila et al, 2012).…”

Section: Discussionmentioning

confidence: 99%

A Multiplex RT-PCR Assay for S. aureus, L. monocytogenes, and Salmonella spp. Detection in Raw Milk with Pre-enrichment

et al. 2017

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This study firstly developed a multiplex real-time PCR (RT-PCR) technique combined with a pre-enrichment step to simultaneously detect Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes) and Salmonella spp. in raw milk and the dairy farm environment (feces, soil, feed, water) in one reaction. Brain heart infusion (BHI) broth was selected for the enrichment step to increase the density of the target bacteria by using an incubation of 4 h before multiplex RT-PCR. The results showed that the detection limit of the multiplex real-time assay was approximately 102 CFU/mL for pure cultures and artificially contaminated milk without enrichment, while 12, 14, and 10 CFU/25 mL, respectively, for S. aureus, L. monocytogenes, and Salmonella spp. after pre-enrichment. The newly developed multiplex RT-PCR assay was applied to 46 dairy farm environmental samples and raw milk samples covering a wide variety of sample types. The results demonstrated that the multiplex RT-PCR assay coupled with the BHI enrichment broth was suitable for the simultaneous screening of S. aureus, L. monocytogenes, and Salmonella spp. in the pasture environment and in raw milk. The multiplex RT-PCR assay clearly and successfully shortened the total detection time and reduced labor compared to conventional culture-based methods for testing natural samples.

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“…The low pH of RV, well tolerated by Salmonella , provides additional selection against coliforms (Rappaport et al, 1956; Vassiliadis et al, 1981; Vassiliadis, 1983). Together the attributes of RV broth, MgCl 2 , low pH, and malachite green, provide a high osmotic pressure, a low pH that declines over time with bacterial metabolism, and inhibition of gram-positive organisms, respectively, that provide favorable conditions for Salmonella growth (van Schothorst and Renaud, 1985; Peterz et al, 1989). An additional selective feature of both RV and TT broths are incubation temperatures above 37°C to reduce competitive bacteria (D’Aoust, 1981; Peterz et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

Early Recovery of Salmonella from Food Using a 6-Hour Non-selective Pre-enrichment and Reformulation of Tetrathionate Broth

et al. 2016

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Culture based methods are commonly employed to detect pathogens in food and environmental samples. These methods are time consuming and complex, requiring multiple non-selective and selective enrichment broths, and usually take at least 1 week to recover and identify pathogens. Improving pathogen detection in foods is a primary goal for regulatory agencies and industry. Salmonella detection in food relies on a series of culture steps in broth formulations optimized to resuscitate Salmonella and reduce the abundance of competitive bacteria. Examples of non-selective pre-enrichment broths used to isolate Salmonella from food include Lactose, Universal Pre-enrichment, BPW, and Trypticase Soy broths. Tetrathionate (TT) and Rappaport–Vassiliadis (RV) broths are employed after a 24-h non-selective enrichment to select for Salmonella and hamper the growth of competitive bacteria. In this study, we tested a new formulation of TT broth that lacks brilliant green dye and has lower levels of TT . We employed this TT broth formulation in conjunction with a 6-h non-selective pre-enrichment period and determined that Salmonella recovery was possible one day earlier than standard food culture methods. We tested the shortened culture method in different non-selective enrichment broths, enumerated Salmonella in the non-selective enrichments, and used 16S rRNA gene sequencing to determine the proportional abundances of Salmonella in the TT and RV selective enrichments. Together these data revealed that a 6-h non-selective pre-enrichment reduces the levels of competitive bacteria inoculated into the selective TT and RV broths, enabling the recovery of Salmonella 1 day earlier than standard culture enrichment methods.

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Malachite green pre‐enrichment medium for improved salmonella isolation from heavily contaminated samples

Cited by 35 publications

References 12 publications

Isolation and characterization of novel bacterial strains exhibiting ligninolytic potential

Isolation and characterization of novel bacterial strains exhibiting ligninolytic potential

A Multiplex RT-PCR Assay for S. aureus, L. monocytogenes, and Salmonella spp. Detection in Raw Milk with Pre-enrichment

Early Recovery of Salmonella from Food Using a 6-Hour Non-selective Pre-enrichment and Reformulation of Tetrathionate Broth

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