| Objective In this study,the relationship between drug resistance and drug resistance genes,pump genes and pump regulatory genes,as well as the frequency of drug resistance genes carried by carbapenem-resistant Klebsiella pneumoniae were investigated in our hospital.Methods A total of 88 strains of Klebsiella pneumoniae were collected from laboratory specimens of our hospital from August 2019 to March 2022.Minimum inhibitory concentration(MIC)was detected by drug sensitivity test,the production of carbapenase was detected by modified carbapenem inactivation method(m CIM),the Hypermucoviscousity was detected by String test,the efflux pump phenotype was detected by efflux pump inhibition test,and the carbapenase resistance gene and efflux pump gene were detected by PCR.The expression of pump gene and its regulatory factors were detected by RT-PCR.Results1.Among the 88 Klebsiella pneumoniae samples,55(63.0%)were sputum,15(17.0%)were urine,8(9.0%)were blood,5(6.0%)were secretions,3(3.0%)were chest and abdominal fluids,and 2(2.0%)were bile.The collected strains were mainly distributed in intensive care(29,33.0%)and respiratory medicine(15,17.0%)wards.Sources from other departments included neurosurgery(10,11.0%),urology(6,7.0%),oncology(5,6.0%),nephrology(4,5.0%).Three strains(3.0%)were isolated from infectious diseases,hepatobiliary surgery,gastrointestinal surgery and neurology.Two strains(2.0%)were isolated from rheumatology and orthopedics,respectively.Only 1strain(1.0%)was isolated from hemorrhoid fistula,interventional vascular and endocrinology.The results of improved carbapenase inactivation test showed that there were 42 strains of KP producing carbapenase,accounting for 87.5% of CRKP.The drug sensitivity test of CRKP against 17 commonly used antibiotics showed that it was resistant to more than 75 percent of nine antibiotics and 31.3 percent of Amikacin(AMK),a relatively sensitive drug.The comparison of drug sensitivity results between CRKP and CSKP showed that,except AMK,the resistance rate of CRKP to most antibiotics was significantly higher than that of CSKP.Statistically,the difference in drug resistance between CRKP and CSKP was statistically significant(P< 0.05).28 strains of Klebsiella pneumoniae were found to have Hypermucoviscousity and belong to hv KP by String Test.The antimicrobial resistance characteristics of hv KP and c KP were analyzed.The resistance rate of c KP to the following antibiotics was significantly higher than that of hv KP strains,but most of them had no statistical significance(P > 0.05).The resistance rate of c KP to imipenem was significantly higher than that of hv KP,with statistical significance(P < 0.05).2.The efflux pump phenotype test results showed that 28(58.3%)of imipenem group had efflux pump phenotype positive,and 16(33.3%)of tigacycline group had efflux pump phenotype positive.Among 48 strains of CRKP,42(87.5%)strains carried carbapenem resistance genes.38(79.2%)strains carried KPC,which was the most common.NDM 14(29.2%)and VIM 14(29.2%)were detected,among which 12 carried both KPC and VIM,and 5 carried both KPC and NDM.IMP and OXA-48 were not detected.89.6% of 48 CRKP strains carried the above 7 pump genes,but only 1strain did not detect any pump genes.The positive rate of 10 pump genes in 88 strains of Klebsiella pneumoniae showed that the detection rate of 5 pump genes was higher in this study,that is,acr B,oqx B,kde A,kpn E and ket M were more than 90%.The detection rate of pump gene kex D was 60.4%,which was the lowest among all pump genotypes detected.The expression levels of pump genes acr A,acr B and tol C of tigacycline resistant CRKP were significantly higher than those of Tigacycline sensitive CRKP,and the expression levels of efflux pump regulation genes ram A and mar A were significantly higher in Tigacycline resistant CRKP than that of Tigacycline sensitive CRKP.Conclusion CRKP is highly resistant to many antimicrobial agents.The resistance of c KP to the following antibiotics was significantly higher than that of hv KP strain.In this study,CRKP carried a high frequency and diversity of carbapenase enzyme genes and efflux pump genes and regulatory factors,and these strains had high drug resistance.CRKP is associated with tigacycline resistant acr AB-tol C efflux pumps. |
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