PICU产超广谱β-内酰胺酶大肠埃希菌耐药率及其与抗菌药物使用频度相关性分析

Antimicrobial resistance of extended spectrum β-lactamase Escherichia coli and its correlation with defined daily doses of antibiotics in pediatric ICU

目的了解儿科重症监护病房(PICU)产超广谱β-内酰胺酶(ESBLs)大肠埃希菌的耐药率、耐药基因及耐药率与抗菌药物使用频度(DDDs)的相关性,为临床儿童重症感染的诊治提供依据。方法采用VITEK-2全自动微生物鉴定仪对102株大肠埃希菌进行鉴定,采用表型确证试验进行ESBLs检测,采用微量肉汤稀释法检测70株产ESBLs大肠埃希菌对氨苄西林等24种抗菌药物的药物敏感性,采用PCR检测耐药基因。结果 102株大肠埃希菌中,70株产ESBLs,检出率为68.6%。70株产ESBLs大肠埃希菌对氨苄西林和头孢唑啉的耐药率高达95.0%以上,对氨苄西林/舒巴坦、氨曲南、头孢吡肟、头孢曲松、哌拉西林、哌拉西林/他唑巴坦、四环素和甲氧苄氨嘧啶/磺胺甲恶唑也存在较高的耐药率(≥50%),检出1株耐亚胺培南大肠埃希菌。耐药基因检出率:intl1为97.1%,amp C为92.9%,tem为62.9%,CTX-M1为25.7%,CTX-M3为37.1%,acc、DHA1、oxa、shv、NDM、fox、per均未检出。携带2、3和4种耐药基因的菌株分别占25.7%(18/70)、25.7%(18/70)和12.9%(9/70)。产ESBLs大肠埃希菌对氨苄西林/舒巴坦和头孢他啶的耐药率与DDDs值呈正相关(r=0.998和0.999,均P<0.05)。结论 PICU产ESBLs大肠埃希菌检出率高,耐药模式复杂;多数菌株包含多个耐药基因,部分药物的DDDs值与大肠埃希菌耐药率呈高度正相关;合理规范使用抗菌药物,加强耐药的监控具有重要意义。

Objective To investigate the antimicrobial resistance of Escherichia coli producing extended spectrumβ-lactamases（ESBLs） and its correlation with defined daily doses（DDDs） of antibiotics in pediatric ICU（PICU）. Methods Total 102 clinical strains of Escherichia coli were identified with VITEK-2, the ESBLs were detected with double disk synergy test. The susceptibility of 70 Escherichia coli producing ESBLs to ampicillin and other antimicrobial agents was detected by broth dilution method and drug resistance genes were detected by polymerase chain reaction（PCR）. Results In 102 Escherichia coli strains, ESBLs were detected in 70 cases（68.6%）, in which the rates of resistance to ampicillin and cefazolin were95.0%, the rates of resistance to ampicillin/sulbactam, aztreonam, cefepime, ceftriaxone, compound sulfamethoxazole,piperacillinsulbactam, tetracyclines and trimethoprim/sulfamethoxazole were all above 50.0%, the resistance to imipenem was detected in one strain. The antimicrobial resistance gene intl1 was detected in 97.1% strains, amp C in 92.9%, tem in 62.9%,CTX-M1 in 25.7%, CTX-M3 in 37.1%, acc, DHA1, oxa, shv, NDM, fox, per genes were not detected. Results showed that25.7%（18/70）, 25.7%（18/70） and 12.9%（9/70） strains carried 2, 3 and 4 strains resistant genes, respectively. The changes of drug resistance of Escherichia coli were significantly correlated with drug DDDs of ampicillin/sulbactam and ceftazidime（r=0.998 and 0.999, both P〈0.05）. Conclusion The detection rate of Escherichia coli producing ESBLs is high in PICU, and the DDDs of some antibiotics are positively correlated with drug resistance, indicating that rational use of antibacterial drugsand strengthening resistance monitoring are important in PICU.