Makindo Medical Notes.com

High mortality from septicaemic melioidosis seen in South India, Thailand and Northern Australia. Incubation period can be many years.

About

• Due to Burkholderia (Pseudomonas) pseudomallei found in soil and rice paddies
• Is most commonly reported in northeast Thailand and northern Australia
• Recurrence is possible - needs prolonged treatment. Seen in immunocompromised
• Many causes are subclinical

Aetiology

• Gram-negative, motile, aerobic bacillus
• From soil and fresh surface water e.g. rice fields in endemic regions
• B pseudomallei contain a heat-stable principle with classic endotoxin activity [

Clinical

• Incubation period of melioidosis can be years (max 26 years)
• Bacilli enter via skin abrasion or ulcer from contact with surface water
• Can also be inhaled - Pneumonia - cavitation resembling TB
• Septic shock is often fatal
• Liver/splenic abscess (misdiagnosed as amoebic)
• Melioidosis encephalomyelitis
• Possible reactivation many years later like TB

Investigations

• Aspiration of pus from abscess shows no organism is a sign
• Culture - Colonies vary from smooth to rough and often become wrinkled after a few days of incubation. There is a pungent odour of putrefaction given off by fresh cultures of the organism.

Mortality rate for melioidosis is 50% in northeast Thailand (35% in children) and 19% in Australia.

Management

• Treat initially with intravenous Ceftazidime 2 g tds 2-3 weeks or Imipenem or Meropenem. Surgical drainage of abscesses.
• This is followed by 12 weeks of oral Doxycycline + Cotrimoxazole + Trimethoprim + chloramphenicol (4 weeks)
• Those with severe disease can be helped by G-Colony stimulating factor

References

• Melioidosis: Review and Update