Melioidosis Presenting as Chronic Pneumonia With Soft Tissue Abscess in a Diabetic Patient Initially Treated for Tuberculosis: A Case Report From Vietnam

ABSTRACT

A 46‐year‐old diabetic Vietnamese engineer presented with a 2‐month fever and left foot swelling. Chest imaging showed bilateral nodules with right apical cavitation, prompting empirical anti‐tuberculosis therapy. Despite positive Xpert MTB/RIF and 1 month of treatment, his condition worsened. Bronchoscopy culture isolated Burkholderia pseudomallei . Treatment with ceftazidime and trimethoprim‐sulfamethoxazole led to complete recovery. Negative MGIT culture excluded tuberculosis co‐infection. This case highlights the diagnostic challenge when melioidosis mimics tuberculosis in endemic regions, particularly in diabetic patients. Positive molecular tuberculosis tests may reflect the previous infection, emphasising the need for culture confirmation and clinical correlation.

A 46‐year‐old diabetic Vietnamese engineer with soil exposure presented with chronic pneumonia and soft tissue abscess, initially misdiagnosed and treated for tuberculosis. Bronchoscopy culture revealed Burkholderia pseudomallei confirming melioidosis, and the patient achieved complete recovery with appropriate antibiotic therapy, highlighting the diagnostic challenge when melioidosis mimics tuberculosis in endemic regions.

1. Introduction

Melioidosis caused by Burkholderia pseudomallei is an emerging infectious disease in Southeast Asia with high mortality rates [1]. Melioidosis can mimic tuberculosis, causing diagnostic difficulties in co‐endemic areas [2]. Vietnam's growing infectious disease network has improved recognition, but the exact disease burden is unknown. Primary risk of Burkholderia pseudomallei infection is diabetes mellitus, which affects most melioidosis patients. We present a case highlighting critical diagnostic considerations when melioidosis presents with tuberculosis‐like features in a diabetic patient.

2. Case Report

A 46‐year‐old male engineer from a major city in the middle region of Vietnam presented after failing anti‐tuberculosis treatment. He had type 2 diabetes with 6 years of irregular treatment, gout for 5 years and had completed tuberculosis treatment 4 years earlier. His job involved frequent soil exposure at construction sites during the rainy season and several episodes of working in flooded areas without personal protective equipment.

He reported 2‐month fever (up to 39°C), dry cough, 5‐kg weight loss, night sweats and progressive left foot swelling up to the ankle over a month. His left foot showed swelling extending from the instep to the ankle joint, without erythema; movement caused difficulty and pain, with no joint effusion. Initial treatment at a provincial hospital included streptomycin, rifampin, isoniazid, pyrazinamide and ethambutol (SRHZE) regimen plus broad‐spectrum antibiotics (imipenem, vancomycin, levofloxacin) for 1 month without improvement. His family history has shown type 2 diabetes in both parents and one sibling with pulmonary tuberculosis.

Examination revealed temperature was 39°C, blood pressure was 120/70 mmHg, pulse was 98/min, respiratory rate was 22/min, and oxygen saturation was 96% on room air. The patient appeared chronically ill, with bilateral lung crackles predominant in the upper fields. On the left foot, diffuse non‐erythematous swelling from the dorsum to the ankle was warm to the touch with no fluctuation (Figure 1). Ultrasound showed a multiloculated fluid collection measuring 1.21 × 0.72 cm in the dorsal region, consistent with a ‘cold abscess’. Movement caused severe pain and difficulty. No inguinal lymphadenopathy was found. Hepatomegaly was present (palpable 2 cm below the costal margin, tender on palpation, soft consistency, smooth surface) without splenomegaly.

FIGURE 1.

Imaging findings of left foot at presentation. (A) Clinical photograph showing diffuse soft tissue swelling extending to the ankle joint. (B) Ultrasound demonstrating multiloculated fluid collection in the dorsal region.

Laboratory findings showed WBC 9410/mm³ (neutrophils 85.8%), haemoglobin 9.3 g/dL, platelets 455,000/mm³, ESR 112/118 mm/h, CRP 190 mg/L, glucose 248 mg/dL, HbA1c 10.6%, sodium 126 mmol/L. Liver and renal functions were normal. Chest CT and x‐ray demonstrated bilateral nodules throughout both lungs, a right upper lobe cavity with thick walls located in the posterior segment, upper lobe fibrosis, and notably absent mediastinal lymphadenopathy. No air‐fluid level was detected in the cavity, and the true apex was relatively spared compared to the posterior/sub‐apical involvement (Figure 2).

FIGURE 2.

Chest imaging findings at presentation. (A) CT chest demonstrating right apical cavity (15 × 20 mm) with surrounding fibrosis and bilateral nodular infiltrates. (B) Chest radiograph showing bilateral nodular infiltrates with right upper lobe cavitation.

Three sputum samples were AFB‐negative with negative mycobacterial cultures. Bronchoscopy revealed purulent secretions in the right upper lobe bronchus. BAL analysis showed positive Xpert MTB/RIF and B. pseudomallei growth after 48 h on Ashdown's agar (sensitive to ceftazidime, meropenem, trimethoprim‐sulfamethoxazole [TMP‐SMX]). Blood cultures remained negative. MGIT mycobacterial culture was negative after 6 weeks. Ultrasound‐guided aspiration of the foot swelling yielded 2 mL of serosanguinous fluid, culture‐negative for bacteria including B. pseudomallei .

Treatment consisted of an intensive phase with IV ceftazidime 2 g q8h plus oral TMP‐SMX (trimethoprim component 6 mg/kg q12h) for 14 days, followed by oral TMP‐SMX for 3 months total. Adjunctive therapy included insulin for glycemic control (target < 180 mg/dL during the acute phase), folic acid supplementation and nutritional support with a high‐protein diet. The patient defervesced by day 6, with progressive foot swelling reduction over 2 weeks and complete mobility restoration. Respiratory symptoms resolved by day 10. At 3‐month follow‐up, he had gained 10 kg, returned to work and showed significant radiological improvement. However, residual radiological changes in the right upper lobe persisted, so we continued maintenance therapy for an additional 3 months.

3. Discussion

This case illustrates the diagnostic pitfalls when melioidosis mimics tuberculosis. Negative MGIT culture suggests that the positive x‐ray transfer detection of DNA from non‐viable mycobacteria indicates a previous infection. This shows that molecular tests should be interpreted within a clinical context, especially in patients with a prior tuberculosis history.

The clinical overlap between melioidosis and tuberculosis is large. Both present with fever, weight loss, cough and cavitary lung disease. Radiologically, both show upper lobe infiltrates and cavitation, though melioidosis characteristically spares the apex while tuberculosis frequently involves the apical segments—a subtle but critical differentiating feature in our patient. The radiological findings, particularly the upper lobe fibrosis, may partially reflect changes from the patient's previous tuberculosis episode 4 years earlier, further complicating the diagnostic interpretation. The absence of mediastinal lymphadenopathy was another diagnostic clue, though this finding is less specific in high‐prevalence areas where reactivation tuberculosis predominates over primary infection in adults. Systematic screening also reveals that up to 2.5% of suspected tuberculosis cases in endemic areas actually have melioidosis [2]. Special attention should be paid to the ‘cold abscess’ presentation. Though both cause musculoskeletal involvement, the combination of pneumonia and soft tissue abscess in a diabetic patient with soil exposure suggests melioidosis [3]. The negative culture from the aspirate of the foot was probably related to prior antibiotic exposure, as B. pseudomallei recovery from pus specimens is less sensitive than respiratory samples [4]. The rapid progression of foot swelling over 1 month also contrasts with the slow course of tuberculous abscesses. Interestingly, while thrombocytopenia frequently occurs in melioidosis cases and predicts mortality, our patient maintained normal platelet counts throughout his illness. In endemic areas, routine screening for Burkholderia pseudomallei should be considered in all suspected tuberculosis cases, particularly those with upper lobe disease that spares the apex, lacks mediastinal lymphadenopathy or presents with the combination of pneumonia and soft tissue abscesses in diabetic patients with soil exposure.

Treatment response aligned with current guidelines. The recent guidelines recommend at least 14 days of intensive therapy for non‐severe pneumonia, although diabetic patients require extended courses. The good response of our patient to standard duration therapy was encouraging, though some experts recommend 6 months of eradication therapy for diabetic patients given their higher relapse risk compared to non‐diabetics [5]. The importance of concurrent diabetes management cannot be overstated, and the patient's good outcome was probably due to achieving glycemic control, among other factors including appropriate antibiotic selection and duration.

Several key lessons are drawn from this case. Primarily, melioidosis should be considered in diabetic patients with tuberculosis‐like presentations in endemic areas with environmental exposure. Second, positive molecular tuberculosis tests require culture confirmation, especially in patients with prior TB history. Third, suboptimal response to anti‐tuberculosis therapy within 2–4 weeks may warrant investigation for alternative diagnoses. Fourth, specific clinical features, including apex‐sparing cavities, absent lymphadenopathy and concurrent soft tissue involvement, should warrant suspicion of melioidosis. Lastly, the absence of bacteremia or thrombocytopenia does not exclude the diagnosis of melioidosis.

This case emphasises that in co‐endemic regions, melioidosis must be considered when chronic pneumonia presents in diabetic patients, particularly with environmental exposure and poor response to empirical tuberculosis treatment. Enhanced diagnostic algorithms incorporating systematic B. pseudomallei screening for AFB‐negative suspected tuberculosis cases could reduce mortality from this treatable but frequently fatal disease.

Author Contributions

H.Q.N. and T.T.D. managed the patient and drafted the manuscript. All authors critically revised the manuscript for important intellectual content and approved the final version of the manuscript.

Ethics Statement

This case report was exempted from formal ethics approval by the Bach Mai Hospital Ethics Committee as per institutional guidelines for single case reports.

Consent

The authors declare that written informed consent was obtained for the publication of this manuscript and accompanying images using the consent form provided by the Journal.

Conflicts of Interest

The authors declare no conflicts of interest.

Nguyen H. Q., Doan T. T., Do T. V., et al., “Melioidosis Presenting as Chronic Pneumonia With Soft Tissue Abscess in a Diabetic Patient Initially Treated for Tuberculosis: A Case Report From Vietnam,” Respirology Case Reports 13, no. 6 (2025): e70257, 10.1002/rcr2.70257.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.