Ahmed S M, Sayeed Md Abu, Sriguha I, Cato E T, Creasy-Marrazzo A, Islam K, Khabir Md I Ul, Bhuiyan Md T R, Begum Y, Islam Md Taufiqul, Khan Zahid Hasan, Freeman E, Vustepalli A, Brinkley L, Kamat M, Bailey L S, Madi N, Qadri F, Shapiro B J, Leung D T, Basso K B, Sack D A, Andrews J R, Khan A I, Nelson E J
Department of Epidemiology, Emory University, Atlanta, GA, USA.
Departments of Pediatrics and Environmental and Global Health, University of Florida, Gainesville, FL, USA.
medRxiv. 2025 May 29:2025.05.14.25327654. doi: 10.1101/2025.05.14.25327654.
Effective cholera outbreak response requires accurate bedside rapid diagnostic tests (RDTs) because access to laboratories is often limited. Formative studies suggest cholera diagnostics have multiple vulnerabilities, including antibiotics and predation by bacteriophage ('phage') specific to ().
We conducted a prospective nationwide study in Bangladesh among over 2000 patients with diarrhoeal disease to characterize how these vulnerabilities impact RDT performance. Assays included culture, qPCR and mass spectrometry.
With the current gold standard of culture or qPCR positivity, we found no effect of phage on RDT performance. When the diagnostic criteria were expanded to include phage, there was a small decrease in RDT sensitivity. In contrast, large increases in sensitivity and specificity were observed among patients with moderate and severe dehydration. Using the expanded definition, the odds of RDT positivity decreased among cholera patients with phage exposure. The effect was most robust among patients with severe dehydration. Antibiotic were detected in over 80% of samples by LC-MS/MS which limited testing for effects on RDTs. Applying these findings, we estimated that restricting RDT use to severe patients with no reported antibiotic exposure increases sensitivity by 50% compared to unrestricted use. If phage were a diagnostic proxy for , we estimate RDT would miss an additional 17% of cholera cases.
Cholera RDTs have critical limitations that require consideration in global deployments. Inclusion of phage detection in diagnostic criteria may improve case detection which requires further study. The impact of these findings likely extends to other diseases where diagnostics share similar vulnerabilities.
有效的霍乱疫情应对需要准确的床边快速诊断检测（RDT），因为进入实验室往往受到限制。形成性研究表明，霍乱诊断存在多个漏洞，包括抗生素以及特定于（）的噬菌体（“噬菌体”）的捕食。
我们在孟加拉国对2000多名腹泻病患者进行了一项前瞻性全国性研究，以确定这些漏洞如何影响RDT性能。检测方法包括培养、定量聚合酶链反应（qPCR）和质谱分析。
以当前培养或qPCR阳性的金标准来看，我们发现噬菌体对RDT性能没有影响。当诊断标准扩大到包括噬菌体时，RDT敏感性略有下降。相比之下，在中度和重度脱水患者中观察到敏感性和特异性大幅提高。使用扩大后的定义，噬菌体暴露的霍乱患者中RDT阳性的几率降低。在重度脱水患者中，这种影响最为明显。通过液相色谱-串联质谱法（LC-MS/MS）在超过80%的样本中检测到抗生素，这限制了对其对RDT影响的测试。应用这些发现，我们估计，与无限制使用相比，将RDT的使用限制在无抗生素暴露报告的重症患者中，敏感性可提高50%。如果噬菌体是（）的诊断替代指标，我们估计RDT会漏诊另外17%的霍乱病例。
霍乱RDT存在关键局限性，在全球部署中需要加以考虑。在诊断标准中纳入噬菌体检测可能会改善病例检测，这需要进一步研究。这些发现的影响可能延伸到诊断存在类似漏洞的其他疾病。
