CN-122012409-A - Culture medium for staphylococcus aureus phage fermentation and fermentation method

Abstract

The invention relates to the technical field of microorganisms, in particular to a culture medium for staphylococcus aureus phage fermentation and a fermentation method. The culture medium for staphylococcus aureus phage fermentation mainly solves the problems of phage infection efficiency reduction and amplification resistance caused by excessive accumulation of host bacteria biomembrane precursor substances caused by high nutrition environment in large-scale culture of staphylococcus aureus phage through components such as whey protein hydrolysate, humic acid and chitosan, improves phage titer and shortens fermentation period.

Inventors

• XU YUE
• CHEN XURAN
• HU XIONG
• KONG LINGTAO
• LI YANG
• LI CUNHAO

Assignees

• 武汉格瑞农生物科技有限公司

Dates

Publication Date

20260512

Application Date

20251224

Claims (9)

1. 1. A culture medium for staphylococcus aureus phage fermentation is characterized in that the components of the culture medium comprise whey protein hydrolysate and humic acid.
2. 2. The culture medium for staphylococcus aureus phage fermentation according to claim 1, wherein the whey protein hydrolysate is used in an amount of 2.5-4.0 g/L and the humic acid is used in an amount of 0.2-0.35 g/L.
3. 3. The medium for phage fermentation of Staphylococcus aureus of claim 1, wherein the medium further comprises chitosan.
4. 4. The culture medium for staphylococcus aureus phage fermentation according to claim 3, wherein the chitosan is used in an amount of 0.6-2.6 g/L.
5. 5. A culture medium for phage fermentation of Staphylococcus aureus as claimed in claim 3, wherein the components of the culture medium further comprise sodium acetate and monascus pigment.
6. 6. The culture medium for staphylococcus aureus phage fermentation according to claim 5, wherein the amount of sodium acetate is 5-9 g/L.
7. 7. The medium for phage fermentation of Staphylococcus aureus of claim 5, wherein the medium further comprises corn cob hydrolysate, tryptone, bile salt and dipotassium hydrogen phosphate.
8. 8. A method for fermenting staphylococcus aureus phage, which is characterized by comprising the culture medium for fermenting staphylococcus aureus phage according to any one of claims 1-7.
9. 9. The method for phage fermentation of Staphylococcus aureus of claim 8, wherein monascus pigment in the medium is used as an indicator for judging the fermentation stage.

Description

Culture medium for staphylococcus aureus phage fermentation and fermentation method Technical Field The invention relates to the technical field of microorganisms, in particular to a culture medium for staphylococcus aureus phage fermentation and a fermentation method. Background Staphylococcus aureus (Staphylococcus aureus) is a gram positive bacterium belonging to the genus Staphylococcus. The strain is a common pathogenic bacterium widely distributed in nature, and can cause various infectious diseases of human beings or animals, such as local abscess, septicemia, sepsis, endocarditis, osteomyelitis and fatal pneumonia. Meanwhile, the strain is one of main pathogenic bacteria for dairy cow mastitis, so that the dairy cow milk yield is often reduced, dairy products are polluted, the safety of the dairy products is affected, and huge economic loss is caused for animal husbandry production. Antibiotics are commonly used in clinic to treat staphylococcus aureus infections such as penicillin, sulfonamides, quinolones, and the like. However, abuse of antibiotics leads to the emergence of resistant strains, even multiple resistant strains, such as methicillin-resistant (METHICILLIN RESISTANT Staphylococcus aureus, MRSA) strains and vancomycin-resistant (Vancomycin Resistant Staphylococcus aureus, VRSA) strains, especially staphylococcus aureus resistance has been increasingly severe in recent years, which brings great trouble to treatment prevention and control. Phage is a bacterial virus that completes a lytic or lysogenic cycle through specific adsorption to bacteria. The virulent phage mainly achieves the purpose of breeding phage filial generation through a lysis period, and can achieve the purpose of lysing bacteria, so that the virulent phage has the effect of killing bacteria, and can be used as a means for treating bacterial infection. The phage has the characteristics of strong specificity, exponential growth and no effect on other normal flora, can be used for carrying out cooperative treatment with antibiotics to achieve the best treatment effect, and is a promising antibiotic substitute. Staphylococcus aureus has evolved from a common bacterium to a representative of the superbacteria MRSA that today stands for the severe form of the global public health system. Due to its increasing resistance to antibiotics, the emergence of an alternative helper strategy for phage mitigation and inhibition of staphylococcus aureus has been accelerated. Therefore, to effectively combat these resistant bacteria, and to address the antibiotic crisis, it is important how to achieve low cost cultivation and efficient fermentation of staphylococcus aureus phage. Disclosure of Invention In view of the above, the invention provides a culture medium for staphylococcus aureus phage fermentation and a fermentation method. The culture medium components such as whey protein hydrolysate, humic acid and chitosan are used for cooperatively solving the problems of phage infection efficiency reduction and amplification resistance caused by excessive accumulation of host bacteria biomembrane precursor substances caused by high nutrition environment in large-scale culture of staphylococcus aureus phage, thereby improving phage titer and shortening fermentation period. The technical scheme of the invention is realized as follows: In a first aspect, the invention provides a medium for phage fermentation of staphylococcus aureus, the medium comprising whey protein hydrolysate and humic acid as components. The whey protein hydrolysate contains various amino acids and growth factors, such as beta-lactoglobulin and immunoglobulin, can be quickly absorbed by host bacteria, promotes metabolism and division of the host bacteria, provides sufficient raw materials for phage replication, and the humic acid provides carbon sources and microelements, is complementary with nitrogen sources of the whey protein hydrolysate in nutrition, and contains vitamins which can promote the activity of host bacteria enzymes, chelate metal ions and further synergistically promote the replication efficiency of phage with the whey protein hydrolysate. On the basis of the technical scheme, preferably, the dosage of the whey protein hydrolysate is 2.5-4.0 g/L, and the dosage of the humic acid is 0.2-0.35 g/L. The rapidly-proliferated staphylococcus aureus can excessively secrete biomembrane precursor substances such as extracellular polysaccharide, extracellular DNA (eDNA) and the like, a invisible barrier layer which is difficult to observe by naked eyes is formed in a fermentation system, the barrier layer can adsorb phage capsids, physically block contact of phage and free staphylococcus aureus, reduce phage passage efficiency and indirectly weaken continuity of lytic amplification, and then positively charged chitosan is added, can be combined with negatively charged phage capsids to enhance stability, and can be electrostatically combined with negatively charg