Application of Ribosomal RNA Gene Restriction Patterns Analysis and Pulsed-Field Gel Electrophoresis in Distinguishing Salmonella Weltevreden Isolates in Malaysia

A representative sample of 20 isolates of Salmonella weltevreden strains from stool cultures of patients admitted at the University Hospital, Kuala Lumpur, Malaysia were analyzed. All the strains were susceptible to ampicillin, ceftriaxone, ciprofloxacin, chloramphenicol, tetracycline, trimethoprim, gentamicin and co-trimoxazole. Ribosomal RNA gene restriction pattern analysis of PstI-digested DNA gave three ribotypes while pulsed-field gel electrophoresis (PFGE) analysis of XbaI-digested DNA gave ten distinct profiles. PFGE was more discriminative than ribotyping in distinguishing the strains. The majority of the strains analyzed were very closely related with similarity coefficient values ranging from 0.8 to 1.0. Both PFGE and ribotyping could distinguish one of the strains which was obtained from a patient following a bone marrow transplant for β-thalassemia major, indicating that this particular strain was unrelated to the rest of the strains from patients with acute gastroenteritis

Melioidosis in Malaysia

Melioidosis is an important cause of sepsis in the tropics, is caused by an environmental saprophyte--B. pseudomallei. It affects mainly adults with underlying predisposing condition such as diabetes. The range of symptoms varies from benign and localized abscesses, to severe community-acquired pneumonia to acute fulminating septicaemia with multiple abscesses often leading to death. B. pseudomallei is an intracellular pathogen and some of the virulence mechanisms that govern the complex interaction between the organism and the host have been elucidated. Isolation of B. pseudomallei from bodily fluids of patients remains the "gold standard" in diagnosis but a sensitive and specific serological test can lend support to the diagnosis of melioidosis. Ceftazidime is the treatment of choice for severe melioidosis, but the response is slow. Maintenance or eradication therapy for a prolonged period is necessary to prevent relapse and recurrence. Monitoring IgG antibody levels may be useful as a guideline to determine the duration of eradication therapy

Melioidosis in Malaysia

Melioidosis is an important cause of sepsis in the tropics, is caused by an environmental saprophyte--B. pseudomallei. It affects mainly adults with underlying predisposing condition such as diabetes. The range of symptoms varies from benign and localized abscesses, to severe community-acquired pneumonia to acute fulminating septicaemia with multiple abscesses often leading to death. B. pseudomallei is an intracellular pathogen and some of the virulence mechanisms that govern the complex interaction between the organism and the host have been elucidated. Isolation of B. pseudomallei from bodily fluids of patients remains the "gold standard" in diagnosis but a sensitive and specific serological test can lend support to the diagnosis of melioidosis. Ceftazidime is the treatment of choice for severe melioidosis, but the response is slow. Maintenance or eradication therapy for a prolonged period is necessary to prevent relapse and recurrence. Monitoring IgG antibody levels may be useful as a guideline to determine the duration of eradication therapy

Comparison of serum F2 isoprostane levels in diabetic patients and diabetic patients infected with Burkholderia pseudomallei

The oxidative stress theory proposes that severe sepsis leads to activation of neutrophils and macrophages which subsequently release reactive oxygen-free radicals that may result in lipid peroxidation of endothelial and epithelial cell membrane phospholipids. This chain reaction results in increased levels of isoprostanes, which are thought to contribute to much of the end-stage tissue damage seen in serious infections, such as melioidosis. We believe that this is the first report linking in vivo oxidative stress status and diabetic patients infected with B. pseudomallei

Salmonella meningitis and its complications in infants.

Infants who developed neurological complications as a result of Salmonella meningitis had significant mortality and adverse long-term neurodevelopment outcome

Burkholderia thailandensis whole cell antigen cross-reacts with B. pseudomallei antibodies from patients with melioidosis in an immunofluorescent assay

An immunofluorescent assay (I FAT) using whole cell antigen derived from Burkholderia thailandensis used for detection of total antibodies to Burkholderia pseudomallei, was found to compare favorably with a previous published report on a 13 pseudomallei IFAT assay. At a 1.20 cut-off titer, the assay had high sensitivity (98 9%) and satisfactory specificity (92.3%), when tested against sera from 94 patients suspected of melioidosis. Sera from 12 patients with culture proven melioidosis gave absolute concordance with the 2 test antigens No sera from 50 blood donors had a titer >= 20 of Cross-reactivity with patients' sera positive for Chlamydia, Mycoplasma, Legionella and typhoid was not observed, except for 3 sera from typhus patients and one from a patient with leptospirosis The major advantage of this assay is that the cultivation and preparation of B. thailandensis as antigen can be carried out in any laboratory with basic microbiological set-up. The serodiagnosis of melioidosis can be made safe for medical laboratory personnel, particularly in B pseudomallei endemic regions

Reduced susceptibility of Malaysian clinical isolates of Burkholderia pseudomallei to ciprofloxacin

Ciprofloxacin, a quinolone with good intracellular penetration may possibly be used for treatment of melioidosis caused by Burkholderia pseudomallei, but problems with resistance may be encountered. Amino acid substitutions in gyrA/gyrB have given rise to fluoroquinolone resistance in various microorganisms. Using published primers for gyrA and gyrB, PCR was performed on 11 isolates of B. pseudomallei with varying degrees of sensitivity to ciprofloxacin, followed by DNA sequencing to detect possible mutations. Results showed an absence of any point mutation in either gene. Local isolates have yet to develop full resistance to ciprofloxacin and probably other mechanisms of resistance may have been involved in the decreased sensitivity to ciprofloxacin

Identification of Burkholderia pseudomallei Mimotope using Phage display approach

This study reportsa sequential biopanning against serum obtained from a patient infected with B. pseudomallei using a phage display peptide library. A peptide bearing the consensus sequence NKNSFDAWLQSF was obtained after 3 rounds of biopanning and it partly resembles the sequence 35FDAWLAAQEF44 of B. pseudomallei site-specific recombinase, which is a phage integrase family protein. Overall, the mimotope obtained in this study could be a potential candidate for the development of a cost effective diagnostic test or vaccine in the future