A Review on Diagnostic Methods for the Identification of Vibrio cholerae

Abstract

The severe diarrheal disease Cholera, has gained public health importance because of its life-threatening effect. The detection of the causative agent of this disease (Vibrio cholerae (V.  Cholerae) O1 or O139) from a specimen (stool, vomitus of food sample) remains a major concern in the world today. Phenotypic finger printing (the conventional methods) of the toxigenic V. cholerae strain, remains the gold standard for the laboratory diagnosis of cholera; especially during cholera epidemic outbreaks. Detection around the remote areas which are usually rampaged by these outbreaks is usually difficult due to lack of required diagnostic facilities in small laboratories. However, the use of phenotypic approaches have some major setbacks as they are usually labor-intensive and time consuming. This delays treatment commencement especially in life threatening cases.To alleviate these setbacks, rapid molecular typing techniques involving the Polymerase chain reaction (PCR) amplification, hybridization methods, Pulsed Field Gel Electrophoresis (PFGE), Multilocus Sequence Typing (MLST), Multiple-Locus Variable Number Tandem Repeat Analysis (MVLA), Fluorescent Amplified Fragment Length Polymorphism (FAFLP),  Whole Genome Sequencing (WGS) etc. represent promising tools for early detection of the pathogen V. cholerae O1/O139 even in remote areas where laboratory resources are poor. Immunoassay-based techniques like enzyme-linked immune-sorbent assay (ELISA), coagglutination, immunofluorescence, and quartz crystal microbalance (QCM), are capital/labour intensive and expensive for low resource settings. Rapid diagnostic tests based on immune-chromatography principle have also been developed for simultaneous detection of V. choleraesero groups O1 and O139. These test kits are easy to use, transport, and fast. All these methods enable the subtyping of unrelated bacterial strains and they all operate with different accuracies, discriminatory ability, and reproducibility. This review sought to address some of the methods used in diagnosing the disease cholera, with the objective of identifying the best and easiest of the methods that can help to curb the cholera problem (deaths) often encountered, especially in low resource settings in the developing countries (Nigeria inclusive).