The choice of antibiotics depends upon the susceptibility of the bacteria to various antibiotics. B. pesudomallei are generally susceptible to ceftazidime, meropenem, imipenem, and co-amoxiclav. These drugs generally kill bacteria. B. pseudomallei is also susceptible to doyxcycline, chloramphenicol, and co-trimoxazole. These drugs generally inhibit the growth of the bacteria. However, the bacteria are resistant to penicillin, ampicillin, 1st and 2nd generation cephalosporin, gentamicin, streptomycin, tobramycin, macrolides, and polymyxins. On the other hand, 86% of the B. pseudomallei isolates from the region of Sarawak, Malaysia are susceptible to gentamicin and this has not been found elsewhere in other parts of the world.Prior to 1989, the standard treatment for acute melioidosis was a three-drug combination of chloramphenicol, co-trimoxazole and doxycycline; this regimen is associated with a mortality rate of 80% and is no longer used unless no other alternatives are available. All three drugs are bacteriostatic (they stop the bacterium from growing, but do not kill it) and the action of co-trimoxazole antagonizes both chloramphenicol and doxycycline. Intensive phase
Intravenous ceftazidime is the current drug of choice for treatment of acute melioidosis and should be administered for at least 10 to 14 days. Meropenem, imipenem and the cefoperazone-sulbactam combination (Sulperazone) are also effective. Intravenous amoxicillin-clavulanate (co-amoxiclav) may be used if none of the above four drugs is available; co-amoxiclav prevents death from melioidosis as well as ceftazidime. Co-amoxiclav is also used if patient has allergy towards sulfonamide, unable to tolerate co-trimaxazole, in pregnant patients or in children.
It is unclear how imported melioidosis is able to persist in a completely new environment. Eventually, the outbreak terminated by itself after a period of time. It was only during the 1980s, Infectious Disease Association of Thailand started took notice of this disease. First conference on melioidosis was held in 1985 in Thailand. It was during this meeting that collaboration between Sappasitprasong Hospital, Thailand, and Wellcome-Mahido-Oxford Tropical Medicine Research Programme was established. Such collaboration made Thailand a world leader in clinical and epidemiology research on melioidosis.In 1989, several studies conducted in Thailand demonstrated ceftazidime as an effective antibiotic against melioidosis. Ceftazidime had been shown to reduce the risk of death of melioidosis from 74% to 37%. In 1990, a non-virulent arabinose-positive B. pseudomallei was found by Vanaporn Wuthiekanun. The organism was later reclassified into a new species called B. thailandensis. This species has become a useful tool in the laboratory for the studies of the pathogenesis of B. pseudomallei. B. pseudomallei was previously classified as part of the genus Pseudomonas. In 1992, the pathogen was formally named B. pseudomallei. In 1994, First International Symposium on melioidosis was held in Kuala Lumpur where 80 delegates attended. Papers were presented and later published as a book. Subsequent congresses were held in Thailand, Australia, and Singapore once every three years. In 2002, B. pseudomallei was classified as a "Category B agent". In 2004, the complete genome of B. pseudomallei was published.