Preparation of microbial suspensions is usually one of the simple, routine and repetitive tasks generally performed in a microbiological laboratory. Commonly used bacterial suspension fluids include bacteriological saline, phosphate buffered saline (PBS) and Ringer’s solution. An ideal suspension fluid should ensure preservation of health of bacterial cells without allowing them to multiply further. However, saline, PBS and Ringer’s solution do not support bacterial viability beyond 6 hours of suspension. Aquino Rehydrol<sup>TM</sup> Rehydration fluid for GPT (Growth Promotion Testing), an isotonic solution helps to resolve the issues faced with these common bacterial suspension fluids.

<strong>Underlying Concept:</strong>

Designing a successful suspension fluid necessitates understanding the complex science underlying these simple formulations. Bacterial cells are surrounded by a highly sensitive, semi-permeable membrane which maintains a continuous dialogue with external environment. This dialogue is facilitated <em>via</em> various facets of cellular machinery.

Porins /aqua-porins located in the cell membrane are amongst the first to respond to changes in the osmotic pressure.  Accumulation of ‘Osmolytes’ (inorganic ions, commonly K<sup>+</sup> and organic molecules like Trehalose, Glutamate, Glycine-Betaine) is another significant response to the osmotic changes in the environment. Co-ordinated control of accumulation and release of these solutes is mediated through various enzymes, transporters and channels. Studies have shown direct correlation of solute concentrations within the cells with the growth rate of the bacterial cells. Growth is found to be directly proportional to cytoplasmic hydration which in turn is governed through solute concentration within the cells. Organic osmolytes are known to rehydrate cytoplasmic environment stimulating the growth of cells. Careful formulation of suspension fluid in coherence to cellular dynamics can impart stability to suspended cells thereby effectively serving the purpose of the formulation.

<strong>HiMedia Innovations: Aquino Rehydrol</strong><sup>TM</sup>

Aquino Rehydrol keeps bacterial cells healthy, viable and stable (without multiplication) in suspension for up to 20 days at -20 ⁰C. This cost - effective solution ensures hassle free growth promotion testing by reducing tedious and time consuming dilution preparations. Clinicians and microbiologists can maintain and study their isolates from any samples/specimens using this multipurpose suspension solution. The convenience of Aquino Rehydrol additionally makes detailed antibiotic sensitivity studies and identification stress-free.

<strong>For more information:</strong>

<em>Dr. Rahul Warke, Ph.D
Director Research and Development (Microbiology),</em>

<em>HiMedia Laboratories Pvt. Ltd.</em>