Prevalence of bla(PenA) and bla(OXA) in Burkholderia pseudomallei Isolated from Patients at Sappasitthiprasong Hospital and Their Susceptibility to Ceftazidime and Carbapenems.

BACKGROUND: Burkholderia pseudomallei is a causative agent of melioidosis. Ceftazidime is the preferred drug of choice for treatment. However, the motility rate is high in endemic areas. OBJECTIVE: This study aimed to determine the susceptibility tofour different antimicrobial agents and to detect the ß-lactamase genes in B. pseudomallei isolates from patients admitted to Sappasitthiprasong Hospital. MATERIAL AND METHOD: 85 B. pseudomallei isolates from patients admitted to Sappasitthiprasong Hospital between November 2010 and May 2011 were determined for antimicrobial susceptibility by standard disk diffusion and minimum inhibitory concentration (MIC). Real-time polymerase chain reaction (PCR) was used for the detection of bla(penA) and bla(OXA) in ß-lactamase genes. RESULTS: Almost all of the clinical isolates ofB. pseudomallei were susceptible to ceftazidime and imipenem. Cefatzidime MIC was ≤ 1-16 µg/ml and imipenem MIC was ≤ 1-4 µg/ml. The real-time PCR revealed that more than 90% of B. pseudomallei isolates carried bla(PenA) and bla(OXA). CONCLUSION: Although the clinical isolates of B. pseudomallei were susceptible to ceftazidime and imipenem, this study showed B. pseudomallei had a gene that produced beta-lactamase enzyme and may be poorly effective in the use of beta-lactam drugs.

Methicillin-resistant Staphylococcus aureus with reduced susceptibility to vancomycin in Sanprasitthiprasong Hospital.

BACKGROUND: Staphylococcus aureus is a species of bacteria that causes a number of diseases and more than 60% of it is presently resistant to methicillin. Vancomycin is the drug of choice for the eradication of methicillin-resistant S. aureus (MRSA). OBJECTIVE: This study aimed to investigate the susceptibility of heterogeneous vancomycin intermediate S. aureus (hVISA) and vancomycin intermediate S. aureus (VISA) to vancomycin by standard disk diffusion, microbroth dilution, a one-point population assay, and a population analysis profile. MATERIAL AND METHOD: Sixty-eight MRSA isolates from patients admitted to Sanprasitthiprasong Hospital between November 2010 and November 2011 were tested. RESULTS: Standard disk diffusion showed that all the MRSA isolates were susceptible to vancomycin. Vancomycin MICs for all isolates were 1-2 microg/mL. Only two MRSA isolates (2.9%) were able to grow on brain heart infusion agar supplemented with vancomycin 4 microg/mL and were confirmed by a population analysis as hVISA. CONCLUSION: This study showed the effect of vancomycin on MRSA and the need for early detection and controlled planning.