Isolation And Biological Characterization Of Staphylococcus Aureus Phages From Bactrian Camels In Xinjiang

Bactrian camel is a common ruminant.There are few reports on the disease of Bactrian camel.Clinically,Staphylococcus aureus is a common bacterial infectious disease in Xinjiang.At present,the main treatment method is antibiotic therapy,but the non-standard use of antibiotics leads to multiple drug resistance problems,resulting in poor therapeutic effect.At home and abroad,we are looking for phage therapy to replace antibiotics for treatment.This study investigated the distribution of staphylococcus from Bactrian camel in Xinjiang.Fifty strains of Staphylococcus were isolated from 264 samples,with a separation rate of 8.94%.There were 8 strains of Staphylococcus aureus,and the isolation rate was 3.03%.Four strains of lytic Staphylococcus aureus phages(phages FH1,FH2,FH3 and FH4)were isolated and purified from Bactrian camel in Xinjiang.Transmission electron microscopy showed that four strains of phages belonged to the order Tailuviridae and the family Long Tail Phage.The titers of phages FH1 and FH2 were 10⁸ PFU/m L,and the titers of phages FH3 and FH4 were 10¹¹ PFU/m L.The MOI of phages FH1 and FH4 was 1,and the MOI of phages FH2 and FH3 was 0.1.Among the 4strains of Staphylococcus aureus phages,the outbreak period of FH4 was the longest,which was100 min,and the outbreak amount was the largest,which was 8 108 PFU/m L,according to the one-step growth curve,indicating that the lytic activity of FH4 was stronger than that of other 3strains of Staphylococcus aureus phages.All four strains of phages were active at 45?to 60?and inactivated at 65?.The four strains of phages still showed high activity at p H 12,indicating that the four strains had strong alkaline resistance,and the four strains had good stability by titer detection.Among the four strains,FH3 and FH4 showed wide cleavage range to the clinical isolates of Staphylococcus aureus.The above characteristics provide basic data for the subsequent experimental study of bacteriophage preparations.The formation of five clinical Staphylococcus aureus biofilms was a dynamic process detected by crystal violet staining.Using separation of four strains of Staphylococcus aureus phage scavenging effect,the phage FH4 used the shortest time and at 8 hours clearance rate higher than 90.00%,the relative to other three phage strains in a relatively short period of time to achieve a better removal effect.Therefore,the ability of bacteriophage FH4 to clear the biofilm is stronger than that of the other three bacteriophages.Through the above studies,we have a preliminary understanding of the 4 strains of Staphylococcus aureus phages,and it is suggested that the phage FH4 can be used as an effective bacteriostatic agent to control the pathogen Staphylococcus aureus.This provides basic data for the application of bacteriophage antibacterial agents in clinical practice.