CN-122012666-A - Propionibacterium acnes selective medium and preparation method thereof

Abstract

The invention relates to a propionibacterium acnes selective medium and a preparation method thereof, wherein the medium comprises casein pancreatin digest, meat gastric enzyme digest, cardiopancreatin digest, yeast extract powder, corn starch, sodium chloride, agar and defibrinated sheep blood, and distilled water is used for volume fixation. Compared with the existing culture medium, the invention has the characteristics of reliable detection and high propionibacterium acnes separation rate, and has good application prospect.

Inventors

• HUANG HAIHUI
• WANG LI
• XU TENG
• XU MENG
• WU SHI
• WAN YINGLU

Assignees

• 复旦大学附属华山医院

Dates

Publication Date

20260512

Application Date

20260330

Claims (5)

1. 1. A propionibacterium acnes selective medium, comprising a casein pancreatin digest, a meat gastric enzyme digest, a cardiopancreatin digest, a yeast extract powder, corn starch, sodium chloride, agar, and defibrinated sheep blood, wherein the medium is sized with distilled water.
2. 2. The propionibacterium acnes selective medium of claim 1, wherein the concentration of the casein pancreatin digest is 10g/L, the meat gastric enzyme digest is 5g/L, the cardiac pancreatin digest is 3g/L, the yeast extract is 10g/L, the corn starch is 1g/L, the sodium chloride is 5g/L, the agar is 15g/L, and the defibrinated sheep blood is 50mL/L.
3. 3. The propionibacterium acnes selective medium of claim 1, further comprising gentamicin sulfate 10mg/L.
4. 4. The propionibacterium acnes selective medium of claim 1, further comprising tween 80 1ml/L.
5. 5. A method of preparing propionibacterium acnes selective medium according to any one of claims 1-4, comprising the steps of: (1) Mixing casein pancreatin digest, meat gastric enzyme digest, cardiopancreatin digest, yeast extract powder, corn starch, sodium chloride, and agar, adding Tween 80 into distilled water to constant volume, adjusting pH to 7.2-7.3,121 deg.C, and sterilizing under high pressure for 45min; (2) Cooling to 45-50deg.C, adding defibrinated sheep blood and gentamicin sulfate, mixing, and pouring into sterile plate.

Description

Propionibacterium acnes selective medium and preparation method thereof Technical Field The invention belongs to the technical field of microorganisms, and particularly relates to a propionibacterium acnes selective medium and a preparation method thereof. Background Acne is a chronic inflammatory disease of pilosebaceous glands characterized by acne, papules, pustules and the like, and has the characteristics of high incidence rate and easy repeated attack. In addition to the incidence of acne associated with androgen levels, increased sebum secretion and abnormal perifollicular cytokeratinization, the inflammatory response caused by propionibacterium acnes hyper-proliferation is also a major cause, and thus is one of the therapeutic means for topical or systemic application of moderately severe acne antibacterial agents. In addition, propionibacterium acnes can cause severe infection such as endocarditis, arthritis and meningitis, and has been reported to be closely related to the onset of atopic dermatitis. Propionibacterium acnes is an obligate anaerobe that mainly colonizes the pilo-sebaceous glands of the skin, and normal flora colonizes both the sebaceous glands and the skin surface. At present, the isolation culture of propionibacterium acnes (Cutibacterium acnes) in a clinical microbiological laboratory mainly depends on a Columbia blood agar plate without antibacterial drugs or on adding colistin and metronidazole into the Columbia blood agar medium. There are also commercial media such as Propionibacterium acnes solid media of the genus Propionibacterium (without antimicrobial). However, the above conventional culture methods have a problem that the detection rate is low in general, possibly due to dominant competitive inhibition of the skin colonization flora, or insufficient nutrient conditions of the culture medium to sufficiently support the growth of the bacteria. CN120442747a discloses a specific medium for propionibacterium acnes, but its application is cosmetic detection. According to the technical Specification for cosmetic safety (2015 edition), the microbial detection of Chinese-specified cosmetics comprises five indexes of colony count, heat-resistant coliform bacteria, staphylococcus aureus, pseudomonas aeruginosa, mould and saccharomycete, wherein the limit value of the colony count of eye, mouth and lip and children cosmetics is less than or equal to 500CFU/g (ml), other products are less than or equal to 1000CFU/g (ml), and pathogenic bacteria cannot be detected. Disclosure of Invention The invention aims to solve the technical problem of providing the propionibacterium acnes selective medium and the preparation method thereof, and has the characteristics of reliable detection and high propionibacterium acnes separation rate compared with the existing medium, and has good application prospect. The invention also provides a propionibacterium acnes selective medium which comprises casein pancreatin digest, meat gastric enzyme digest, cardiopancreatin digest, yeast extract powder, corn starch, sodium chloride, agar and defibrinated sheep blood, and distilled water is used for volume fixation. Preferably, the concentration of the casein pancreatin digestate is 10g/L, the meat gastric enzyme digestate is 5g/L, the cardiopancreatin digestate is 3g/L, the yeast extract powder is 10g/L, the corn starch is 1g/L, the sodium chloride is 5g/L, the agar is 15g/L and the defibrinated sheep blood is 50mL/L. Further, the culture medium also comprises 10mg/L gentamicin sulfate. Further, the culture medium also comprises 1mL/L Tween 80. The invention also provides a preparation method of the propionibacterium acnes selective medium, which comprises the following steps: (1) Mixing casein pancreatin digest, meat gastric enzyme digest, cardiopancreatin digest, yeast extract powder, corn starch, sodium chloride, and agar, adding Tween 80 into distilled water to constant volume, adjusting pH to 7.2-7.3,121 deg.C, and sterilizing under high pressure for 45min; (2) Cooling to 45-50deg.C, adding defibrinated sheep blood and gentamicin sulfate, mixing, and pouring into sterile plate. According to the invention, the casein pancreatin digest, the meat gastric enzyme digest, the heart pancreatin digest, the yeast extract powder and the corn starch provide carbon and nitrogen sources, vitamins and growth factors, sheep blood is a good nutrient substance for bacterial growth and reproduction, and certain thermolabile growth factors in blood can be preserved by adding blood into a basic culture medium at 45-50 ℃, and blood cells are not destroyed. Tween 80 stimulates propionibacterium acnes growth. Gentamicin sulfate at a proper concentration can inhibit the growth of gram-negative bacteria such as staphylococcus, streptococcus and enterobacteriaceae, but does not affect the growth of propionibacterium acnes. Advantageous effects Compared with the existing culture medium, the invention has the characteristics of