Cheardchai Soontornpas. In Vitro antimicrobial susceptibilities of Burkholderia Pseudomallei and pharmacokinetics and pharmacokinetics of Ceftazidime in melioidosis patients. Doctoral Degree(Biopharmaceutical Sciences). Mahidol University. : Mahidol University, 2009-07-09.
In Vitro antimicrobial susceptibilities of Burkholderia Pseudomallei and pharmacokinetics and pharmacokinetics of Ceftazidime in melioidosis patients
Abstract:
Burkholderia pseudomallei is the causative microorganism of melioidosis, a
fatal community-acquired infection endemic in tropical areas including Northeast
Thailand. The recommended therapy uses antimicrobials such as ceftazidime,
cotrimoxazole, cefoperazone/sulbactam, doxycycline and ciprofloxacin. However,
there are doubts as to the continuing sensitivity of this treatment. Therefore, 119
clinical isolates were subjected to in vitro susceptibility testing by the disk diffusion
test and they showed high sensitivity to these antimicrobials. Thirty of these isolates
were further tested for the minimum inhibitory concentration and the minimum
bactericidal concentration by the microbroth dilution test. They showed similar results
but these antimicrobials did not seem to behave as bactericidal agents. A time-kill
study supported this finding and also showed that the combination of doxycycline and
cotrimoxazole had antagonistic effect. In conclusion, the results showed that
ceftazidime is a continuing effective agent.
As ceftazidime is the drug of choice for the treatment of severe melioidosis in
Thailand, pharmacokinetic and pharmacodynamic studies were performed to
determine the appropriate dosage regimen for melioidosis patients. The studies tested
with three dosage levels (1, 1.5, and 2 g) and 10 patients were recruited in each dose.
Then, the serum ceftazidime concentrations were simulated to steady state from
multiple dose or continuous intravenous infusion. The results showed that ceftazidime
1 g every 8 h or 3 g/day may be used for the treatment of melioidosis in patients when
the minimum inhibitory concentration is equal to or less than 2 μg/mL. However, the
serum concentration maintained as 4 times of the MIC (8 μg/mL) might not be
enough to eradicate the microorganism from the infection site