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