| In order to understand the drug resistance of E.coli and enterococci in the living environment of pets in Chengdu,15 pet-related premises in urban areas were used as collection points to obtain samples from air and surfaces accessible to animals,and to isolate and identify E.coli and enterococci,while categorising and analysing the samples according to their sources to clarify the relationship between different environmental factors and the isolation rate and drug resistance of the target strains.In addition,multi-drug resistant strains were tested for the main resistance genes ofβ-lactams,quinolones and tetracyclines according to the resistance phenotypes of the tested strains,and correlation analysis was performed with environmental factors.The results are reported as follows:1.A total of 433 samples were collected from the environment of eight pet hospitals,two animal clinics and five pet trading markets,including 98 samples from air sources and335 samples from the surfaces of objects.A total of 174 strains of E.coli（40.18%isolation rate）and 288 strains of enterococci（66.51%isolation rate）,all with typical culture characteristics,were isolated and identified by differential culture and 16S r RNA sequencing.The results of the statistical analysis showed that the target bacteria could be isolated in environments with different levels of cleanliness,with the isolation rate of Enterococcus being higher than that of E.coli,suggesting that Enterococcus may be the dominant bacteria in the environment;the isolation rates of E.coli and Enterococcus were significantly higher in environments with low levels of cleanliness than in environments with high levels of cleanliness（P<0.05）;the isolation rates of E.coli and Enterococcus were higher in the environment of pet trading markets than in The isolation rate of E.coli and enterococci was higher than that of animal hospitals and animal clinics;the isolation rate of bacteria on surfaces was higher than that of air.This suggests that the overall cleanliness of the pet living environment in Chengdu is not high and the level of hygiene is low.2.The resistance phenotypes（K-B method）and minimum inhibitory concentrations（MICs）of the commonly used antibiotics Cefotaxime CFX,Ampicillin AMP,Doxycycline DOX,Amoxicillin-clavulanic acid AMC and Enoxacin ENR were determined for 174 E.coli and 288 Enterococcus strains isolated.（K-B method）and minimum inhibitory concentration（MIC）for Ampicillin AMP,Doxycycline DOX,Amoxicillin-clavulanic acid AMC and Enoxacin ENR.The results showed that the resistance rates of E.coli isolates to the tested drugs were 78.73%（137/174）for cefotaxime,62.06%（108/174）for doxycycline,54.59%（95/174）for enrofloxacin and 22.98%（40/174）for amoxicillin-clavulanic acid in the order of resistance,with the highest proportion of dual resistant bacteria at 67.81%（118/174）and 65 multi-drug resistant strains,accounting for 37.35%（65/174）,suggesting that the isolated E.coli were seriously resistant to drugs,mainly toβ-lactams and tetracyclines;the resistance rates of enterococcal isolates to the tested drugs were:doxycycline 73.59%（213/288）,enrofloxacin 63.19%（182/288）,ampicillin 21.18%（61/288）,amoxicillin-clavulanic acid 20.13%（58/288）,and 55 multi-drug resistant strains,accounting for 19.09%（55/288）,suggesting that enterococci are seriously resistant to drugs,mainly tetracyclines and fluoroquinolones.Analysis of drug resistance genes associated with 65 multi-drug resistant Escherichia coli and 55 multi-drug resistant Enterococcus spp.Tetracycline resistance genes tet B and tet A had the highest detection rates of 100%（65/65）and 92.30%（60/65）,followed byβ-lactam resistance genes bla TEMand bla CTX-Mwith 75.38%（49/65）and 70.76%（46/65）,respectively,while fluoroquinolone resistance gene qnr S had the lowest detection rate of21.53%（14/65）,indicating that E.coli drug-resistant strains mainly had tet A,tet B,bla TEMand bla CTX-Mas prevalent genes;55 strains of enterococci that showed multi-drug resistance to the selected drugs were tested for three categories and five resistance genes,and theβ-lactam resistance gene bla TEMhad the highest detection rate,with a detection rate of41.81%（23/55）.The tetracycline resistance gene tet M was detected at a rate of 14.54%（8/55）.tet A and tet B were not detected.The quinolone resistance gene qnr S was not detected.This indicates that enterococcal drug-resistant strains were mainly prevalent with bla TEMas the gene.Conclusion:This study found higher isolation rates of target bacteria in poorly cleaned premises and higher isolation rates of target bacteria in pet trading markets than in the other two types of premises.E.coli was predominantlyβ-lactam and tetracycline resistant,and Enterococcus was predominantly tetracycline and fluoroquinolone resistant.The prevalent genes of drug-resistant strains of E.coli were predominantly tet A,tet B,bla TEMand bla CTX-M,and the prevalent genes of drug-resistant strains of enterococci were predominantly bla TEM.We are prompted to choose our antimicrobial drugs wisely and to avoid drugs with severe resistance profiles. |
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