Immunochromatographic Lateral Flow Device Developed for Cholera

Currently, the gold standard to detect Vibrio cholerae is still the bacterial culture method, which is laborious, time-consuming and lacks sensitivity; however several modern diagnostic methods have been developed.

Cholera is an acute malignant infectious disease caused by the bacteria V. cholerae leading to severe dehydrating diarrhea and vomiting, even high rates of mortality in some cases. The prevention of the epidemic disease is achievable if proper sanitation practices are followed provided the accurate and prompt diagnosis of each prevalent serotype in cholera epidemics.

Scientists at the Chongqing Medical University (China) collaborating with colleagues at Artron BioResearch Inc. (Burnaby, BC, Canada) developed an immunochromatographic test format for the V. cholerae O1 serotype Ogawa diagnosis and which may provide the need for better epidemic prevention and early response.

Monoclonal antibodies were raised in conventional method and subsequently screened for a matched pair. A variety of related and unrelated bacteria strains were employed to test their sensitivity, specificity by indirect enzyme-linked immunosorbent assay (ELISA). A total of 726 diarrhea patients’ feces samples from July 2012 to September 2012 were examined by an in-house Immunochromatographic Lateral Flow Device, commercial strips from Zhuangdi Haohe Biological Medicine Co., Ltd. (Beijing, China) and standard bacterial culture method in parallel for comparison. The human fecal samples were used to test the final lateral-flow device product to satisfy the measurement requirement.

To perform a test, after full contact with the sample solution, the strips were kept at room temperature for five minutes. Two bands that appeared at both the test and control sites represented a positive test result. Only one band at the control location represents a negative test result. The absence of a line at the control site means the test was invalid. The detection threshold for bacterial culture of the strip was 1.0 × 104 colony forming units (cfu)/mL, which is higher than the current stipulated threshold of 1.0 × 105 cfu/mL.

The authors concluded that they had successfully developed rapid diagnostic test (RDT) strips for cholera by conducting systematic evaluation to assess its specificity, sensitivity and reliability. The product was capable of distinguishing the V. cholerae O1 Ogawa and V. cholerae O1 Inaba, which filled the gaps of the area in rapid cholera diagnosis. Overall, the outcome confirmed that the RDT has superior detection aspects than other parallel commercial products. The study was published in the April 2014 issue of the journal Clinical Biochemistry.

Related Links:
Chongqing Medical University
Artron BioResearch Inc.
Zhuangdi Haohe Biological Medicine Co., Ltd.