临床菌株中B类和A类β-内酰胺酶的分布：表型方法与高分辨率熔解分析（HRMA）检测的比较

Distribution of Class B and Class A β-Lactamases in Clinical Strains of : Comparison of Phenotypic Methods and High-Resolution Melting Analysis (HRMA) Assay.

作者信息

Dehbashi Sanaz, Tahmasebi Hamed, Alikhani Mohammad Yousef, Keramat Fariba, Arabestani Mohammad Reza

机构信息

Microbiology Department, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran.

Microbiology Department, Faculty of Medicine, Zahedan University of Medical Sciences, Zahedan, Iran.

出版信息

Infect Drug Resist. 2020 Jun 30;13:2037-2052. doi: 10.2147/IDR.S255292. eCollection 2020.

BACKGROUND

There are various phenotypic methods for identifying class B and class A β-lactamase enzymes in . The purpose of this study was to compare the sensitivity and specificity of different phenotypic methods with HRMA assay to detect β-lactamase-producing strains.

METHODS

Eighty-eight of isolates were collected from different specimens. Conventional double-disk test (DDT) and EDTA-imipenem microbiological (EIM) were performed to detect ESBL and MBL-producing strains, respectively. Meanwhile, the Modified Hodge test and Carba-NP test were performed on all carbapenem-resistant strains. HRMA method and sensitivity and specificity of primers were determined based on the melt curve temperature range. In all comparisons, PCR was considered as the gold standard.

RESULTS

Of the 402 isolates collected from different clinical specimens, 88 isolates of were identified. However, 43 strains were (48.88%) ESBL-producing, and 7 strains (7.95%) were MBL-producing. Also, using the Modified Hodge test and Carba-NP method, 11 (12.5%) and 19 (21.59%) strains were carbapenemase-producing, respectively. The results of the HRMA test revealed that genes coding for , , , , and were detected in 44.31%, 22.72%, 13.63%, 14.7%, 5.6%, and 2.27% of isolates. Nonetheless, for and genes, sensitivity and specificity of the Carba-NP test were 90.47%, 94.87%, and 83.36%, 94.80%, respectively. However, sensitivity and specificity of MHT was 91.66%, 98.70%, and 77.77%, 96.42%, respectively. For and genes, sensitivity and specificity of DDT were 95.55%, 95.55%, and 86%, 83.50%, respectively. However, sensitivity and specificity of EMI were 77.77%, 97.59%, and 91.66%, 97.43% for and , respectively.

CONCLUSION

The HRMA is a powerful, accurate, closed-tube, rapid method for detecting β-lactamase genes in . The high sensitivity and specificity of this method, along with phenotypic tests, play a useful role in increasing the predictive value of clinical reports.

背景

有多种表型方法可用于鉴定[未提及具体物种]中的B类和A类β-内酰胺酶。本研究的目的是比较不同表型方法与高分辨率熔解曲线分析（HRMA）检测产β-内酰胺酶[未提及具体物种]菌株的敏感性和特异性。

方法

从不同标本中收集了88株[未提及具体物种]分离株。分别采用常规双纸片协同试验（DDT）和EDTA-亚胺培南微生物学方法（EIM）检测产超广谱β-内酰胺酶（ESBL）和产金属β-内酰胺酶（MBL）菌株。同时，对所有耐碳青霉烯类菌株进行改良Hodge试验和Carba-NP试验。根据熔解曲线温度范围确定HRMA方法及引物的敏感性和特异性。在所有比较中，聚合酶链反应（PCR）被视为金标准。

结果

从不同临床标本中收集的402株分离株中，鉴定出88株[未提及具体物种]。然而，43株（48.88%）为产ESBL菌株，7株（7.95%）为产MBL菌株。此外，采用改良Hodge试验和Carba-NP方法，分别有11株（12.5%）和19株（21.59%）为产碳青霉烯酶菌株。HRMA试验结果显示，在[未提及具体物种]分离株中，编码[未提及具体基因名称]、[未提及具体基因名称]、[未提及具体基因名称]、[未提及具体基因名称]、[未提及具体基因名称]和[未提及具体基因名称]的基因分别在44.31%、22.72%、13.63%、14.7%、5.6%和2.27%的菌株中被检测到。然而，对于[未提及具体基因名称]和[未提及具体基因名称]基因，Carba-NP试验的敏感性和特异性分别为90.47%、94.87%和83.36%、94.80%。然而，改良Hodge试验的敏感性和特异性分别为91.66%、98.70%和77.77%、96.42%。对于[未提及具体基因名称]和[未提及具体基因名称]基因，DDT的敏感性和特异性分别为95.55%、95.55%和86%、83.50%。然而，对于[未提及具体基因名称]和[未提及具体基因名称]，EMI的敏感性和特异性分别为77.77%、97.59%和91.66%、97.43%。