多重耐药假单胞菌属细菌对碳青霉烯类和氨基糖苷类抗生素耐药的分子机制研究

Molecular Mechanism Study on the Resistance of Multidrug-resistant Pseudomonas to Carbapenems and Aminoglycosides Antibiotics

【目的】探讨多重耐药假单胞菌属细菌对碳青霉烯类和氨基糖苷类抗生素耐药的分子机制。【方法】选2022年1月至12月于本院检验科收到的来自该医院不同病区的6株多重耐药恶臭假单胞菌和铜绿假单胞菌。采用Vitek-2compact全自动鉴定仪和16s rDNA序列引物鉴定并核实细菌种属。E-test药敏试条法测定菌株对临床抗生素抑菌浓度。PCR扩增和序列对比明确氨基糖苷类和碳青霉烯酶类甲基化酶的基因亚型。【结果】6株假单胞菌属细菌中有4株铜绿假单胞菌、2株恶臭假单胞菌,均为Carba NP阳性,且产碳青霉烯酶;菌株对青霉素类、碳青霉烯类、氨基糖苷类、头孢菌素类、四环素类抗生素均显示为耐药性。6株菌株中,仅SY456为氨曲类耐药,最小抑菌浓度值(MIC值)为92μg/mL,而其他菌株均为氨曲类耐药中介或敏感。Carba NP法筛查出6株菌均产耐药B类碳青酶烯酶。经与overlap PCR序列比对显示,6株菌株携带armA基因和blaIMP-45基因,3株恶臭假单胞菌SY47、SY153和SY434之间的脉冲场凝胶电泳(PFGE)带型差异显著。【结论】本院存在同时携带armA和blaIMP-45的多重耐药恶臭假单胞菌和铜绿假单胞菌,临床医师需根据耐药菌株类型调整用药策略。

【Objective】To explore the molecular mechanism of resistance of multidrug-resistant Pseudomonas to carbapenems and aminoglycosides antibiotics.【Methods】Six strains of multidrug-resistant Pseudomonas aeruginosa and Pseudomonas aeruginosa were received from different wards of our hospital from January 2022 to December in the laboratory department.The bacterial species were identified and verified using the Vitek-2 compact fully automated identification instrument and 16s rDNA sequence primers.The E-test drug sensitivity test was used to determine the antibacterial concentration of the strain against clinical antibiotics.The gene subtypes of aminoglycoside and carbapenemase methylases were identified through PCR amplification and sequence comparison.【Results】Among the 6 strains of Pseudomonas genus bacteria,4 strains were Pseudomonas aeruginosa and 2 strains were Pseudomonas putida,both of which were Carba NP positive and produced carbapenemase;The strains showed resistance to penicillin,carbapenems,aminoglycosides,cephalosporins,and tetracycline antibiotics.Among the 6 strains,only SY456 was resistant to aflatoxin with a MIC value of 92μg/mL,while the other strains were mediators or sensitive to aflatoxin resistance.The Carba NP method screened 6 strains of bacteria,all of which produced drug-resistant B-class carbapenemases.The overlap PCR sequence comparison showed that six strains carried armA gene and blaIMP-45 gene,and three strains of Pseudomonas putida SY47,SY153,and SY434 had significantly different pulse field gel electrophoresis(PFGE)bands.【Conclusion】There are both Pseudomonas aeruginosa and Pseudomonas aeruginosa carrying both armA and blaIMP-45 in our hospital.Clinical physicians need to adjust their medication strategies in a timely manner based on the type of drug-resistant strains.