| It has reported that zoonotic pathogens are carried by zoos animals.The freerange mode of zoos has the opportunity to spread pathogens from animals to humans through fecal-oral.At present,there is no epidemiological investigation on drug resistance of Gramnegative isolates of ornamental poultry in a zoo in Henan Province.To understand the role of free-range poultry park in the spread of drug-resistant isolates,and to provide reference for further prevention and control of drug-resistant isolates spread,the drug resistance characteristics of Gram-negative isolates to familiar drugs were detected from free-range poultry in a zoo.In this study,79 Gram-negative isolates were obtained from 45 poultry samples,which identified 15 species.The main isolates were Escherichia coli,Proteus mirabilis,Klebsiella pneumoniae and Enterobacter hormaechei.The susceptibility results showed that 79 isolates were severely resistant to amoxicillin,followed by cefotaxime,which were sensitive to amikacin.The sensitivity to other drugs is related closely to the species of isolates.A total of 16 bla CTX-M-positive strains were detected by PCR amplification,including 10 bla CTX-M-positive E.coli,the dominant ST type was ST10.Genomic analysis of bla CTX-Mpositive K.pneumoniae LYS105 A showed that the mobile plasmid p LYS105A-2 contained17 drug resistance genes including bla CTX-M-3.The multi-drug resistance region together with two IS1X2 V in the same orientation constitute a novel transposon Tn7131 and mediate the loop-forming transfer of it.Meanwhile,the increased expression levels of acr EF-tol C,oqx AB and pho PQ resulted in LYS105 A being resistant to tigecycline and intermediate to colistin.6 P.mirabilis were resistant to cefotaxime,one carrying bla CTX-M-14,one carrying bla ACT-16,while the remaining four strains(17B,21 A,25B,29B2)showed the same clone by PFGE.Real-time relative quantitative PCR results confirmed a significant correlation between these resistance to cefotaxime and decreased expression of outer membrane proteins omp C and omp F and increased expression of omp W.A tet(X)-positive strain,Acinetobacter indicus LYS68 A,was detected by PCR amplification.Whole genome sequencing results showed that LYS68 A did not carry a plasmid,and carried nine drug resistance genes including tet(X6)and tet(X3)on its chromosome,which constitutes a 29,252 bp multi-drug resistance region and could be inserted as a whole into the genome.The genetic environment of drug resistance genes tet(X6)and tet(X3)showed 99% homology to the first reported tet(X6)and tet(X3),respectively.In summary,the Gram-negative isolates from free-range poultry in this city zoo had serious drug resistance.The strains carrying bla CTX-M and tet(X)may play an important role in the transmission of drug-resistant intestinal isolates in humans and poultry,and should be paid attention. |
