| Shigella(also known as dysentery bacillus)is an important zoonotic pathogen.With the rapid development of cattle and sheep farming in China,diarrhea in cattle and sheep is widespread on farms and occurs for complex reasons.Many pathogens cause bacterial diarrhea in cattle and sheep,such as enterotoxin-producing Escherichia coli and Salmonella.In addition,the long-term abuse of antimicrobial drugs has produced many drug-resistant strains of Shigella,which seriously limits the effective prevention and control of the disease.The investigation of drug resistance and pathogenicity of Shigella spp.of cattle and sheep origin in the Xinjiang Ta’er Reclamation area still needs to be completed.Therefore,the study can provide a reference for preventing and controlling Shigella of cattle and sheep origin in Xinjiang Ta’er Reclamation Area.In this study,335 cattle and sheep diarrhea feces were collected from different areas of Xinjiang Ta’er Reclamation Area in March-April 2022,and Shigella bovis and sheep were isolated and cultured using SS agar identification medium,and a total of 32 Shigella strains were identified by PCR amplification and sequencing with morphology and 16 S r DNA universal primers.The drug susceptibility test of the isolates was performed by the K-B paper sheet method.The results showed that the resistance rates of 32 Shigella strains of bovine and sheep origin to 13 antibacterial drugs ranged from 9.38% to 87.5%,with higher resistance rates to tetracycline(28/32,87.5%),doxycycline(28/32,87.5%)and ampicillin(27/32,84.38%).The resistance to cotrimoxazole(19/32,59.37%),cefothiophene(18/32,56.25%),gentamicin(18/32,56.25%),streptomycin(17/32,53.13%)and ceftiofur(16/32,50%)showed different degrees of resistance.The results showed 2 positive biofilm strains,30 Shigella strains with no film-forming ability,1 strain with moderate film-forming ability,and only 1 song with film-forming solid knowledge,which showed that most bacteria in this test had no biofilm-forming power.The drug resistance gene carriage results of 32 Shigella strains showed that 14 drug resistance genes were detected,including tet A,tet M,gyr A,gyr B,par C,bla TEM,bla CXT-MU,cmla,oqx A,oqx B,etc.Among them,tet A and tet M were detected in tetracyclines,and the detection rates were 84.38%(27/32).Among them,tet A and tet M were detected in tetracyclines,with detection rates of 84.38%(27/32)and 71.88%(23/32),respectively;gyr A,gyr B,and par C were detected in quinolones,with detection rates of 100%(32/32),96.88%(31/32)and 100%(32/32),respectively;bla TEM and bla CXT-MU were detected in β-lactams,with detection rates of 96.88%(31/32)and 68.75%(22/32),respectively.68.75%(22/32);cmla was detected by chloramphenicol with 46.88%(15/32);oqx A and oqx B were detected by efflux pumps with 28.13%(9/32)and 3.13%(1/32),respectively;sul1 and sul2 were detected by sulfonamides with 43.75%(14/32)and 18.75%(6/32);aminoglycosides were detected aph and ant with 90.63%(29/32)and 31.25%(10/32)detection rates,respectively.The detection rate of 18 virulence genes was 100%(32/32)for sod A and mat;96.88%(31/32)for she A;yijp was detected at 93.75%(30/32);ibe B at 90.63%(29/32);ipa BCD at 78.13%(25/32);ics A at 62.5%(20/32);ial at 50%(16/32);sen,iuc D 46.88%(15/32);stx1 12.5%(4/32);bor 6.25%(2/32);est A,stx23.13%(1/32).The isolates were tested for pathogenicity in mice.The results showed that the isolates all showed pathogenicity,and the dissection revealed varying degrees of lesions in the liver,kidney,lung,and spleen.In this test,19 D-amino acids were selected,and two D-amino acids(D-phenylalanine and D-valine)were screened for their inhibitory effects on the biofilm of Shigella(273-1).The results showed that the minimum inhibitory concentration of D-phenylalanine in combination with amikacin and doxycycline in Shigella(273-1)was reduced from 256 μg/m L.The results showed that the minimum inhibitory concentration of D-phenylalanine in combination with amikacin and doxycycline was decreased from 256μg/m L to 64 μg/m L and from 256 μg/m L to 16 μg/m L in combination with doxycycline.The molecular epidemiological investigation of Shigella of bovine and sheep origin in Ta’er Reclamation Area,Xinjiang,especially analyzing its drug resistance and virulence gene distribution,provides a basis for controlling Shigella of bovine and sheep origin in Ta’er Reclamation Area,Xinjiang. |
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