A Case of Melioidosis: Still Unresolved and Undetected in Unexplored Regions

Melioidosis, a tropical disease, is considered endemic in southeast Asia and Australia [4]. The causative agent, B. pseudomallei is a gram negative soil-dwelling bacilli, often acquired through contaminated or abraded skin or inhalation of dust contaminated with the organism [5]. The concerned patient own agricultural lands and poultry farms although he denied being involved in farming himself. Nonetheless, he supervised cultivation on paddy fields which may lead to inoculation of the bacteria.

Melioidosis can present with a myriad of clinical symptoms, for which definite diagnosis depends on the isolation and identification of B. pseudomallei from clinical specimens [6]. Although, it has been mentioned earlier that urinary tract melioidosis is uncommon, in Bangladesh, previously 13.2% melioidosis patients presented with burning sensation in micturition [7,8]. Bangladesh is considered a definite country for melioidosis, owing to the presence of the organism in both clinical and soil specimen [9]. Culture remains the gold standard for the isolation of B. pseudomallei from clinical specimens, followed by identification of the bacteria by colony morphology, biochemical analysis and antimicrobial resistance pattern as the isolate is intrinsically resistant to aminoglycosides and colistin [10]. However, in Bangladesh, when laboratories are suddenly faced with a melioidosis case outside the capital city of Dhaka, identification becomes difficult because of the lack of specific signs of the disease along with minimal clinical and laboratory experience regarding the disease. The case study illustrates how this diagnosis could come as a bit of a surprise to a standard diagnostic laboratory outside Dhaka city. Moreover, previously no patient was identified from the Northern region of the country which provides reason for the unfamiliarity of the microbiologists of the said laboratory to suspect and identify the organism [11].

Since B. pseudomallei is categorized as a Biosafety Level 3 agent, the microbiology laboratory must be well equipped to handle the organism [6]. If the organism is not accurately identified, laboratory personnel may be accidentally and unintentionally exposed. A laboratory staff involved in cleaning culture plates, was diagnosed with melioidosis in 2020 in the Department of Microbiology, BIRDEM General Hospital which has also raised concern regarding maintenance of biosafety while handling the organism [7]. However, as there have only been a few documented laboratory-acquired cases, it is reasonable to conclude that the real risk is minimal if safe work procedures are followed [12,13].

Diabetes mellitus, chronic kidney disease, thalassaemia, alcoholic usage, chronic lung disease, male gender, age > 45 years, and immunosuppression are among the risk factors for developing melioidosis [14,15]. Our patient exhibiteddiabetes mellitus, old age and male gender as risk factors. Previously, in Bangladesh, 83.82% melioidosis patients were male, with 88.23% of patients having diabetes as a comorbidity [7].

pseudomallei is resistant to penicillin, first-/second-generation cephalosporins, colistin and aminoglycosides [5,16].It also shows some degree of resistance to quinolones[6]. The intensive therapy should include ceftazidime, imipenem or meropenem followed by a longer eradication period with co-trimoxazole, amoxicillin-clavulanate or doxycycline depending on susceptibility testing [5,16]. In our patient, initially the patient was treated with ciprofloxacin to which the isolate later demonstrated resistance. Even after a diagnosis of melioidosis was made, the patient’s antibiotic regimen included oral tetracycline instead of injectable antibiotics mentioned above. Finally, one month after diagnosis, intensive therapy began with meropenem following which the patient reported improved physical condition. Till the case report has been written, the patient has received the antibiotic for 3 weeks following which he reported improved physical condition.