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CHROMagar

Written by MicroDok

Selective Growth of Colistin Resistant Bacteria on CHROMagar™ COL-APSE

CHROMagar™ COL-APSE is a sensitive and specific medium for the selective growth of colistin resistant bacterial pathogens.

Polymyxin E (colistin) and B are increasingly used as antimicrobials in the treatment of multi-drug resistant bacterial infections. Although intrinsic in Gram-positive and some Gram-negative species (Proteus, Morganella, Serratia), polymyxin resistance is now a problem in a number of other pathogens (Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, Salmonella enterica, Klebsiella pneumoniae).

Resistance arises due to mutations / insertions in genes involved in LPS biosynthesis (lpx, pmrA/B, mgrB, phoP/Q) and/ or the acquisition of phosphoethanolomine transferases (PEtN).

The recently described plasmid-encoded PEtN, MCR-1, is of great concern and is now found worldwide in a range of animal, human and environmental bacterial isolates.

CHROMagar™ COL-APSE is particularly useful as a primary isolation medium in the surveillance and recovery of colistin resistant bacteria from complex human, veterinary and environmental samples especially those with plasmid mediated MCR-1 or novel mechanisms of polymyxin resistance.

CHROMagar™ Campylobacter

Campylobacter bacteria are a major cause of foodborne diarrhoeal illness in humans and are the most common bacteria that cause gastroenteritis worldwide. In developed and developing countries, they cause more cases of diarrhoea than foodborne Salmonella. The high incidence of Campylobacter diarrhoea, as well as its duration and possible consequences makes it very important from a socio-economic perspective. In developing countries, Campylobacter infections in children under the age of two years are especially frequent, sometimes resulting in death.

The most common gastrointestinal infections in humans are caused by the Campylobacter jejuni and C. coli species.

Currently screening for Campylobacter is a culture based method using a charcoal-based selective media or a blood containing media. These culture plates are incubated for up to 72 hours and their lack of selectivity allows for the growth of large amounts of other flora. Therefore ISO (10272-1 :2006) requires the use of a second medium to workaround these deficiencies.

CHROMagar™ Campylobacter is a chromogenic medium that is both selective and differential for the isolation of this enteric pathogen. This medium also requires incubation in a microaerophilic atmosphere at 42 °C, however distinct red colonies of Campylobacter will grow after 24 hours and a negative report can be issued after 48 hours incubation rather than 72 hours.

CHROMagar™ Campylobacter medium can decrease the turnaround time from sample to result and therefore significantly improve patient diagnosis and workflow of food testing laboratories.

With CHROMagar™ Campylobacter, no compromises! This medium combines highly specific and easy to read chromogenic technology with an unrivalled growth agar base.

Key Features and Benefits:

  • EASY TO READ – 24-48 h incubation at 42 °C. The intense red colored colonies on a translucent agar facilitates the reading compared to charcoal based agar.
  • HIGH RECOVERY RATE – ~100 % enumerating Campylobacter has never been so simple and so reliable.
  • HIGHLY SELECTIVE – a greater selectivity results in a very clean plate, even for samples with high background flora.

CHROMagar™ C. perfringens

Clostridium perfringens is involved in both food poisoning and animal infections. CHROMagar™ C.perfringens allows for the detection and numeration of C. perfringens  in food and water samples.

Specific and selective, colonies of C. perfringens appear orange and also fluorescent under UV light at 365nm, any other microorganisms being blue, metallic blue or are inhibited from growing.

One drawback of TSC medium that is often used for C. perfingens is that bacteria have to be placed between two layers of agar in order to grow as black colonies. Also, this medium will make any sulfate-reducing bacteria, including the non pathogens appear as black colonies. Moreover, there is tendency for the black colonies to spread, making colony counting difficult.

However, CHROMagar™ C.perfringens can be used with either pouring or surface methods (by direct streaking, spreading or with the filtration technique), the medium is specific for C.perfringens and the orange coloration makes the visualization very easy.

CHROMagar TM Mastitis Detects Most Common Pathogens in Mastitis Infections

Clinical mastitis remains an important animal health issue, affecting from 20% to 30% of dairy cows at least once during lactation. Lack of Mastitis infection control in cattle causes heavy economic losses to milk producers and to the dairy industry as it causes a reduction in the quality of milk and output, and increases veterinary expenses due to excessive use of medications, and risk of residues in the milk/ meat. Consequently, this becomes a public health issue.

Estimated costs per infection of clinical mastitis range from $178 to $489 depending on stage of lactation, milk prices and production level in affected cows.

The most common causes of antibiotic use in dairy cows are the treatment and prevention of mastitis. In order to avoid its indiscriminate antibiotic use and to reduce the economic burden of clinical mastitis, it is critical to implement an on-farm rapid identification of the pathogens.

CHROMagarTM Mastitis is a new commercially available tool for the rapid and simple differentiation of the key bacteria involved in Mastitis infections. This new product is supplied as a kit with two separate media, one for gram-positive bacteria (GP), and the other for gram-negative bacteria (GN).

Colony Appearance on CHROMagar Mastitis GP

  • Strep agalactiae → blue-green
  • Strep uberis → metallic blue
  • Staph aureus → mauve with mauve halo
  • Gram negative bacteria → inhibited

Colony Appearance on CHROMagar Mastitis GN

  • E.coli → red
  • Klebsiella, Enterobacter, Citrobacter → metallic blue
  • Proteus → brown halo
  • Pseudomonas → cream, translucent
  • C.albicans → white, opaque, small
  • Gram positive bacteria → inhibited

New CHROMagar™ Campylobacter for Food and Clinical Samples

Campylobacter bacteria are a major cause of foodborne diarrhoeal illness in humans and are the most common bacteria that cause gastroenteritis worldwide. In developed and developing countries, they cause more cases of diarrhoea than foodborne Salmonella. The high incidence of Campylobacter diarrhoea, as well as its duration and possible sequelae, makes it highly important from a socio-economic perspective. In developing countries, Campylobacter infections in children under the age of two years are especially frequent, sometimes resulting in death.

The most common gastrointestinal infections in humans are caused by the Campylobacter jejuni and C. coli species.

Current screening for Campylobacter is a culture based method using a charcoal-based selective media or a blood containing media. These culture plates are incubated for up to 72 hours and their lack of selectivity allows for the growth of large amounts of flora. Therefore ISO (10272-1 :2006) requires the use of a second medium to palliate these deficiencies.

CHROMagar™ Campylobacter is a new chromogenic medium that is both selective and differential for the isolation of this enteric pathogen. This medium also requires incubation in a microaerophilic atmosphere at 42°C, however distinct red colonies of Campylobacter will grow after 24 hours and a negative report can be issued after 48 hours incubation rather than 72 hours.

This new CHROMagar™ Campylobacter medium can decrease the result turnaround time and therefore significantly improve patient diagnosis and workflow of both clinical and food testing laboratories.

With CHROMagar™ Campylobacter, no compromises! This medium allies the highly specific and easy to read chromogenic technology with an unrivalled growth agar base.

Key Features and Benefits:

  • EASY READING – 24-48h incubation at 42°C. The intense red colored colonies on a translucent agar facilitates the reading compared to charcoal based agar.
  • HIGH RECOVERY RATE – ~100% Enumerating Campylobacter has never been so simple and so reliable.
  • HIGHLY SELECTIVE – a reinforced selectivity allows for a very clean plate, even with heavily flora loaded samples

Source:

https://www.rapidmicrobiology.com/news/selective-growth-of-colistin-resistant-bacteria-on-chromagar-col-apse

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MicroDok

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