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秘鲁儿童对引起菌血症的大肠埃希菌中喹诺酮类、头孢菌素类和大环内酯类的耐药性

发布者:抗性基因网 时间:2020-04-23 浏览量:981

       摘要

       目标:
       对62株引起秘鲁儿童菌血症的大肠埃希菌的β-内酰胺类、喹诺酮类和大环内酯类耐药水平及其机制进行了研究。
       方法:
       测定了苯丙氨酸-β-萘胺存在和不存在时环丙沙星、萘啶酸和阿奇霉素的最低抑菌浓度(MICs)。对其他14种抗菌药物的敏感性也被确定。鉴定了超广谱β-内酰胺酶(ESBLs),并检测了gyrA和parC的突变,以及喹诺酮类耐药(TMQR)和大环内酯类耐药(TMMR)的转移机制。
       结果:
       50株(80.6%)为多重耐药菌株。对氨苄西林(93.5%)、醛(66.1%)和甲氧苄啶/磺胺甲恶唑(66.1%)的耐药率较高。无一株对碳青霉烯类抗生素耐药,仅有2株对呋喃妥因耐药。27个分离株携带ESBL编码基因:2个blaSHV-12;13个blaCTX-M-15;4个blaCTX-M-2;6个blaCTX-M-65;和2个未鉴定的ESBL。此外,还检测到27个blaTEM-1和9个blaOXA-1样基因。所有耐喹诺酮类药物的菌株都显示了靶点突变,而TMQR在四个菌株中都存在。射流泵在本构阻力中起作用。喹诺酮类药物耐药与产ESBL有显著相关性(P=0.0011)。mph(A)基因是TMMR最常见的16个分离株,msr(A)和erm(B)基因也被检测到。当外排泵被抑制时,只有一个携带分离物的TMMR(同时出现mph(A)和erm(B))对阿奇霉素仍有耐药性。
      结论:
      已发现多种ESBL编码基因和blaCTX-M-15在Lima的广泛分布。外排泵在阿奇霉素耐药中的作用需要进一步评估,以及有效控制抗菌药物的使用。


OBJECTIVES:

To characterise the β-lactam, quinolone and macrolide resistance levels and mechanisms in 62 Escherichia coli isolates causing bacteraemia in Peruvian children.

METHODS:

Minimum inhibitory concentrations (MICs) of ciprofloxacin, nalidixic acid (NAL) and azithromycin were determined in the presence and absence of Phe-Arg-β-naphthylamide. Susceptibility to other 14 antimicrobial agents was also established. Extended-spectrum β-lactamases (ESBLs) were identified, and mutations in gyrA and parC as well as the presence of transferable mechanisms of quinolone resistance (TMQR) and macrolide resistance (TMMR) were determined.

RESULTS:

Fifty isolates (80.6%) were multidrug-resistant. High proportions of resistance to ampicillin (93.5%), NAL (66.1%) and trimethoprim/sulfamethoxazole (66.1%) were observed. No isolate showed resistance to carbapenems and only two isolates were resistant to nitrofurantoin. Twenty-seven isolates carried ESBL-encoding genes: 2 blaSHV-12; 13 blaCTX-M-15; 4 blaCTX-M-2; 6 blaCTX-M-65; and 2 non-identified ESBLs. Additionally, 27 blaTEM-1 and 9 blaOXA-1-like genes were detected. All quinolone-resistant isolates showed target mutations, whilst TMQR were present in four isolates. Efflux pumps played a role in constitutive NAL resistance. The association between quinolone resistance and ESBL production was significant (P=0.0011). The mph(A) gene was the most frequent TMMR (16 isolates); msr(A) and erm(B) genes were also detected. Only one TMMR-carrying isolate [presenting mph(A) and erm(B) concomitantly] remained resistant to azithromycin when efflux pumps were inhibited.

CONCLUSIONS:

A variety of ESBL-encoding genes and widespread of blaCTX-M-15 in Lima has been shown. The role of efflux pumps in azithromycin resistance needs to be further evaluated, as well as effective control of the use of antimicrobial agents.

        https://www.sciencedirect.com/science/article/abs/pii/S2213716517301339?via%3Dihub