Detection of Coxsackievirus A16 by reverse transcription loop-mediated isothermal amplification

Rapid detection of four major HFMD-associated enteroviruses by multiplex HiFi-LAMP assays

Hand, foot, and mouth disease (HFMD) caused by various enteroviruses is a major public health concern globally. Human enterovirus 71(EVA71), coxsackievirus A16 (CVA16), coxsackievirus A6 (CVA6), and coxsackievirus A10 (CVA10) are four major enteroviruses responsible for HFMD. Rapid, accurate, and specific point-of-care (POC) detection of the four enteroviruses is crucial for the prevention and control of HFMD. Here, we developed two multiplex high-fidelity DNA polymerase loop-mediated isothermal amplification (mHiFi-LAMP) assays for simultaneous detection of EVA71, CVA16, CVA6, and CVA10. The assays have good specificity and exhibit high sensitivity, with limits of detection (LOD) of 11.2, 49.6, 11.4, and 20.5 copies per 25 μL reaction for EVA71, CVA16, CVA6, and CVA10, respectively. The mHiFi-LAMP assays showed an excellent clinical performance (sensitivity 100.0%, specificity 83.3%, n = 47) when compared with four singleplex RT-qPCR assays (sensitivity 93.1%, specificity 100%). In particular, the HiFi-LAMP assays exhibited better performance (sensitivity 100.0%, specificity 100%) for CVA16 and CVA6 than the RT-qPCR assays (sensitivity 75.0-92.3%, specificity 100%). Furthermore, the mHiFi-LAMP assays detected all clinical samples positive for the four enteroviruses within 30 min, obviously shorter than about 1-1.5 h by the RT-qPCR assays. The new mHiFi-LAMP assays can be used as a robust point-of-care testing (POCT) tool to facilitate surveillance of HFMD at rural and remote communities and resource-limited settings.

Diagnostic value of loop-mediated isothermal amplification assay for hand, foot, and mouth disease

BACKGROUND

Nowadays, hand, foot, and mouth disease (HFMD) has a significant negative impact on children's health, especially in the Asia-Pacific region. Loop-mediated isothermal amplification assay (LAMP) is a highly efficient and convenient novel tool. However, its diagnostic accuracy for HFMD is still not clear. Therefore, we conducted a meta-analysis in order to evaluate the potential of LAMP assay for the diagnosis of HFMD, in which the reference standard was polymerase chain reaction (PCR).

METHODS

A protocol was predetermined (CRD42020212882) in PROSPERO. We retrieved seven databases including PubMed for relevant studies published before October 2020. Articles were included if they compared the diagnostic efficiency of LAMP with PCR for HFMD through detecting clinical samples which was more than 15. Statistical analysis was performed by STATA 15.1 software. Risk of bias and applicability were assessed using Quality Assessment of Diagnostic Accuracy Studies. No funding was used for the study.

RESULTS

A total of 18 retrospective studies including 2495 samples from China were finally included. Reference standards of them included RT-PCR and non-RT-PCR. The merged sensitivity and specificity with 95% confidence interval (95% CI) were 1.00 (0.97-1.00) and 0.97 (0.88-0.99), respectively. The pooled PLR, NLR, and DOR with 95% CI were 11.17 (5.91-21.11), 0.05 (0.03-0.09), and 538.12 (183.17-1580.83), respectively. The AUC of SROC was 1.00 (95% CI: 0.99-1.00).

CONCLUSION

In conclusion, our research revealed high sensitivity and specificity of LAMP in diagnosing HFMD. However, more high-quality research is required to prove this conclusion.