Quality control strains, what are they?

Since the 2015 version of the Pharmacopoeia came into effect, the quality control strains, the commercial derivatives of the standard strains slowly warmed up, the original microbiology laboratory, most of the use of CMCC strains, and therefore basically buy the 0 generation of the standard strains of the Institute of China's standard strains to make a generation of the standard storage strains and then made into working strains for use, or buy the local preparation of the 2-3 generation of the commercial derivatives of the strain as a working strains. In fact, many foreign companies have used quality control strains as the basic consumables for their microbiology laboratory strain experiments, but the commodities on the market are basically limited to the strains of the European and American strain conservation centers such as ATCC, NCTC, NCPF, etc., and it is basically difficult to find the quality control strains for CMCC strains (China Medical Bacteria Conservation and Management Center).

    QC strains are essentially commercial derivatives of standard strains, which should have reliable traceability to the source of the standard strains used, and can only be used as working strains in microbiology laboratories, and their identity and purity should be confirmed before use. Quality control quantitative strains are very easy to use, basically just use sterile water to reconstitute the bacterial pellet, and then use it after shaking or within its allowed storage conditions and time. 

QC strains are basically divided into two categories:

One type to meet the needs of low concentration of inoculum, the bacterial content is generally <100cfu, for various types of microbial culture medium to promote the growth of experiments, microbiological experiments, positive control, aseptic process simulation tests in the sensitivity of the medium to check the aseptic or microbial limit of the experiments of the methodological validation of the inoculum needs.

The other category is to meet the demand for high concentration of inoculum, the bacterial content is generally 105-106cfu, for the efficacy of antimicrobial active substances such as preservatives, bacteriostatic agents and disinfectants, or challenge experiments, this type of experiments on microorganisms have a decline in a few logarithmic decline in the statistical needs, so the need for relatively high concentration of bacterial solution.

The advantages of QC strains are obvious, most notably the following three:

1, accurate known strain cfu number, reduce the experimental failure rate

The advantages of this point is really very large, the laboratory to establish a stable dilution of various strains to quantitative methods require at least 3 to 6 months, training personnel can effectively implement the method of each person basically need 3 months, the test bought strains of the original situation is not the same, even if the same strain of bacteria, the same resuscitation methods, cultivation conditions, cultivation time, the same method of dilution, but the amount of bacteria diluted out by different people is not the same, each microbiology laboratory certainly encountered the same strain of cfu, reduce experimental failures. Each microbiology laboratory must have encountered the same day dilution to join the test material found the next day after counting results over the limit, or the day counting the next day in the refrigerator to take out the bacteria in the liquid strains are dead did not appear to have a positive reaction of the situation, these experiments need to be redone, if it is raw materials or finished product testing will be difficult to account for the test, so the quality control of the strain can be stable quantitative characteristics of this Appears to be particularly meaningful to the laboratory, which makes the success rate of microbiological experiments greatly improved.

2, quality control strains of cfu quantity stability, reduce the difference between samples

This point is very useful in doing microbiological verification of all kinds, because to do all kinds of sample comparison, if the amount of strains added to the smaller the difference between the results of the evaluation will be more accurate, such as the actual amount of positive test material added to the 10cfu, the actual amount of positive control added to the 90cfu, although both meet <100cfu, but for the final microbial growth judgment will bring some problems, if it is the In the case of aseptic examination and other experiments that only look at the growth of the strain, there may be different judgments of weak growth and good growth, and the same for quantitative experiments may also have an impact on the recovery rate of the experiment. But if you use quality control strains, you can more accurately judge the results and avoid such problems.

3. Greatly reduce the preparation time of the experiment, easy to use and reduce costs.

Traditional strain experiments need to go through the strain recovery, culture, dilution and other processes, but also need to prepare the culture medium, consumables with the experiment, such as Aspergillus niger light recovery after the culture will take 5-7 days, plus do the experiments, at least from 7 days before the start of the preparations, but the quality control strains of experiments only require sterile water and personnel have a certain ability to operate aseptically coupled with the use of pipette guns can be used, for the experiments of P. aeruginosa, A. niger, and other strains that are more difficult to control is also not a problem. For strains such as Aspergillus niger and other experimental strains that are more difficult to control, there is no need for personnel to spend time practicing, and ordinary laboratory personnel can be competent, which on the other hand, can actually reduce personnel costs.

Of course, quality control strains also need to ensure and to be refined issues, summarized in the following three points:

1. Traceability:

Because it is a commercial strain, so the traceability of the strain used and the certificate of analysis is quite important, the production process must be controlled and meet the standards of the standard material manufacturers, before using its characteristics and purity must be confirmed.

2. Stability of bacterial quantity:

The product should be able to ensure that the same batch and between different batches of bacterial stability; in addition, after the product is re-solubilized, in the preservation of its prescribed conditions within a period of time should try to make the bacterial stability, should minimize the standard error.

3、Temperature problem during transportation and storage:

Because the product is a live strain of bacteria, its temperature, especially high temperature may have a certain effect on the product, so in the transportation and storage process should be strictly based on the product temperature requirements.

In fact, the above problems in the supplier audit stage focus on the traceability of the quality control strains, bacterial volume stabilization technology and product transportation methods for investigation, to find a stable quality control and excellent qualification of the supplier can be solved.

For modern microbiology laboratories, the use of quality control strains is a necessary way of laboratory development, the use of quality control strains can greatly reduce the cost of experiments and personnel control, and greatly improve the success rate of microbiology experiments, and make microbiology experiments into the quantitative rationality of the era, looking forward to more and better CMCC's quality control strains products to come out, for the convenience of China's pharmaceutical companies to bring the convenience of microbiology laboratories and support.