Related Experiment Video
Updated: Jun 18, 2026
Simplified Whole Body Plethysmography to Characterize Lung Function During Respiratory Melioidosis
Published on: February 24, 2023
False-positive widal in melioidosis
Rohith Valsalan1, S Shubha, C Mukhopadhyay
1Department of Medicine, Kasturba Medical College, Manipal, India. drrohithv@gmail.com
Abstract:
Enteric fever is endemic in this part of the world, and Widal test is one of the time-honored laboratory tests that are being used for years to diagnose the disease. On the other hand, melioidosis is a newly emerging disease from this region, which is most often misdiagnosed or underdiagnosed by clinicians. It is well accepted that false-positive Widal reactions following certain non-typhoid Salmonella infections may occur commonly. Three cases of high titers of Widal test are described, where melioidosis was the actual diagnosis in every occasion and was never suspected until diagnosed microbiologically. All the patients had shown a partial response to ceftriaxone. Blood and pus cultures grew Burkholderia pseudomallei, whereas Salmonella typhi was not isolated from blood in any patient. With appropriate antibiotics, the patients showed clinical and microbiological improvement with lowering of Widal titers. These 3 cases show that high Widal titer in any patient may mislead the diagnosis of melioidosis, and further laboratory workup should always be done to rule out melioidosis, especially in cases with nonresponsiveness to treatment.
Insights
High Widal titers can misdiagnose melioidosis, an emerging disease. Microbiological testing is crucial for accurate diagnosis, especially when patients show poor response to initial treatment for enteric fever.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Clinical Diagnostics
Background:
- Enteric fever diagnosis often relies on the Widal test, a long-standing method in endemic regions.
- Melioidosis, caused by Burkholderia pseudomallei, is an emerging infectious disease in the region, frequently misdiagnosed.
- False-positive Widal reactions are known to occur with non-typhoid Salmonella infections.
Observation:
- Three cases presented with high Widal titers, initially suggesting enteric fever.
- Melioidosis was the actual diagnosis in all three cases, unrecognized until microbiological confirmation.
- Patients showed only partial response to ceftriaxone treatment.
Findings:
- Blood and pus cultures confirmed Burkholderia pseudomallei in all patients.
- Salmonella typhi was not isolated from blood cultures in any of the cases.
- Treatment with appropriate antibiotics led to clinical and microbiological improvement, with decreasing Widal titers.
Implications:
- High Widal titers can be misleading, potentially masking melioidosis diagnoses.
- Further laboratory investigations are essential to rule out melioidosis in patients with high Widal titers, particularly those unresponsive to treatment.
- This highlights the importance of considering emerging infectious diseases in differential diagnoses, even with seemingly indicative serological results.
Related Concept Videos
01:25Rapid Identification of Pathogens
01:26Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...