Forty-five years old man of Bangladesh origin presented to the A&E with a 2-month history of cough, fever, haemoptysis and weight loss. Chest X-ray (CXR) revealed upper right lobe haziness and a cavity. WCC – 13 x10^9/L (Normal 4 – 11 x10^9/L ), normal renal function, mildly raised Alanine aminotransferase (ALT) and bilirubin, CRP of 50 mg/L (Normal<5 mg/L) . Sputum was acid-fast bacilli (AFB) negative and had been sent for AFB culture. CT abdomen thorax pelvis– confirmed the cavitation and showed some hypodense area in his spleen.
He has been to Bangladesh recently to visit his flood affected family members. The patient has a background history of diabetes and on
Sputum culture grew this bacteria(see picture for the colony).
It is an aerobic, gram-negative bacillus, sensitive to co-amoxiclav but resistant to amoxicillin, gentamicin, erythromycin, aztreonam.
Would you consider the bacteria significant?
What is your provisional diagnosis?
What treatment would you consider?
What infection control or precautionary measure would you take considering the epidemiology and the sputum culture result?
It is significant. Considering the history and pure growth.
The organism must be considered here is Burkholderia pseudomallei, which causes melioidosis. Other diagnoses which should be considered from the history are tuberculosis, malignancy, sarcoid etc.
10-14 days of IV treatment (Ceftazidime/meropenem +/- cotrimoxazole) and then
3-6 months oral ( cotrimoxazole/ doxycycline BD) antibiotic.
Infection control and laboratory safety: It is a category 3 pathogen. Inhalation is a known method of transmission – sample should be processed in category 3 room. Precaution should be taken during the aerosol-generating procedures.
Inform PHE, (Consider the possibility of deliberate release. not this case but it can be used for bioterrorism), isolation of the patient, respiratory precaution for the aerosol-generating procedures, standard precaution otherwise.
Endemic in South east Asia/South Asia/ Northern Australia. Bangladesh is less known but 5 cases have been imported from there (equal numbers from Thailand). Sporadic cases have been reported from Africa, India, Pakistan, South America etc.
Usually acquired from percutaneous inoculation, inhalation, ingestion. Human to human transmission extremely rare. Infection from animal exposure – rare.
It can affect a healthy person but the risk increases with immunosuppression, steroid, heart failure, haemosiderosis. Natural disasters also increase risk.
Incubation period – 1-20 days
Clinical presentation – pneumonia, bacteraemia, sepsis, skin and soft tissue infection, abscess, genitourinary infection, CNS infection, arthritis, osteomyelitis, parotitis etc
Diagnosis- Culture, microscopy (safety-pin appearance), Mass spectrometry (MALDI ToF), serology, PCR (RIPL),
gene sequence-based technology.
Rapid antigen detection test is being used now.
Selective media for B pseudomallei – Ashdown’s media
Ceftazidime, Imipenem or meropenem.
Cotrimoxazole has often added as a 2nd agent to the treatment regimen for its intracellular activity, and to prevent the development of resistance during treatment.
Intensive IV therapy is recommended for 10-14 days but for deep-seated or severe infection 4-8 weeks of intensive therapy is often necessary.
Eradication therapy follows after the acute phase (for 3-6 months)– Cotrimoxazole/doxycycline.