Furqan Warda, Ali Sakhawat, Usman Javaid, Hanif Faisal, Naeem Afnan, Nasrullah Amnah, Tayyab Nadia
Department of Microbiology Army Medical College (National University of Medical Sciences), Rawalpindi, Pakistan.
Infect Drug Resist. 2022 Oct 10;15:5899-5904. doi: 10.2147/IDR.S376490. eCollection 2022.
Members of Enterobacterales are very common pathogens, which continue to show resistance to many antibiotics. Carbapenem performed well for some time. Colistin was the final hope for the carbapenem-resistant Enterobacterales, but resistance against it has virtually tied the clinician's hands, especially when it comes to treating critically ill patients.
Detection of colistin resistance by the agar method as well as by the polymerase chain reaction (mobilized colistin resistance-1 gene) in carbapenem-resistant Enterobacterales.
A cross-sectional study from Dec 2019 to Dec 2020 was conducted at the Department of Microbiology, Army Medical College, National University of Medical Sciences Rawalpindi Pakistan. Antimicrobial susceptibility of Enterobacterales was determined according to the Kirby-Bauer disc diffusion method except for colistin. Colistin agar was used, in concentrations of 2 µg/mL and 4 µg/mL. Results were interpreted according to Clinical and Laboratory Standards Institute guidelines 2020. Mobilized colistin-resistant-1 gene in the carbapenem resistant Enterobacterales was detected by performing real-time polymerase chain reaction assay.
Among the 172 carbapenem-resistant Enterobacterales 18 isolates were resistant using the colistin agar test. Whereas by molecular method colistin resistance was detected among 10 isolates that carried mobilized colistin resistance 1 gene, making the frequency of the MCR-1 gene 5.81%. Seventy percent of isolates were from paired blood samples. Eight patients, from whom the colistin resistant gene was isolated expired.
Colistin resistance is a very serious issue and should not be missed in a clinical microbiology laboratory. The phenotypic agar test method is an excellent option for routine use, as it combines ease of performance with affordable cost. However, molecular methods are essential for the detection of mobilized colistin resistance gene (1-9) for epidemiological purposes.
肠杆菌科细菌是非常常见的病原体，对许多抗生素仍表现出耐药性。碳青霉烯类抗生素曾在一段时间内效果良好。黏菌素曾是耐碳青霉烯类肠杆菌科细菌的最后希望，但对其的耐药性几乎让临床医生束手无策，尤其是在治疗重症患者时。
采用琼脂法以及聚合酶链反应（检测可移动黏菌素耐药基因-1）检测耐碳青霉烯类肠杆菌科细菌对黏菌素的耐药性。
2019年12月至2020年12月在巴基斯坦拉瓦尔品第国立医科大学陆军医学院微生物学系进行了一项横断面研究。除黏菌素外，根据 Kirby-Bauer 纸片扩散法测定肠杆菌科细菌的药敏性。使用浓度为2µg/mL和4µg/mL的黏菌素琼脂。结果根据2020年临床和实验室标准协会指南进行解读。通过实时聚合酶链反应检测耐碳青霉烯类肠杆菌科细菌中的可移动黏菌素耐药基因-1。
在172株耐碳青霉烯类肠杆菌科细菌中，18株通过黏菌素琼脂试验检测为耐药。而通过分子方法，在10株携带可移动黏菌素耐药基因-1的菌株中检测到黏菌素耐药，MCR-1基因频率为5.81%。70%的菌株来自配对血样。分离出黏菌素耐药基因的8名患者死亡。
黏菌素耐药是一个非常严重的问题，临床微生物实验室不应忽视。表型琼脂试验方法是常规使用的极佳选择，因为它操作简便且成本低廉。然而，分子方法对于检测可移动黏菌素耐药基因以用于流行病学目的至关重要。
