h Melioidosis is a potentially fatal disease caused by the saprophytic bacterium Burkholderia pseudomallei. Resistance to gentamicin is generally a hallmark of B. pseudomallei, and gentamicin is a selective agent in media used for diagnosis of melioidosis. In this study, we determined the prevalence and mechanism of gentamicin susceptibility found in B. pseudomallei isolates from Sarawak, Malaysian Borneo. We performed multilocus sequence typing and antibiotic susceptibility testing on 44 B. pseudomallei clinical isolates from melioidosis patients in Sarawak district hospitals. Whole-genome sequencing was used to identify the mechanism of gentamicin susceptibility. A novel allelic-specific PCR was designed to differentiate gentamicin-sensitive isolates from wild-type B. pseudomallei. A reversion assay was performed to confirm the involvement of this mechanism in gentamicin susceptibility. A substantial proportion (86%) of B. pseudomallei clinical isolates in Sarawak, Malaysian Borneo, were found to be susceptible to the aminoglycoside gentamicin, a rare occurrence in other regions where B. pseudomallei is endemic. Gentamicin sensitivity was restricted to genetically related strains belonging to sequence type 881 or its single-locus variant, sequence type 997. Whole-genome sequencing identified a novel nonsynonymous mutation within amrB, encoding an essential component of the AmrAB-OprA multidrug efflux pump. We confirmed the role of this mutation in conferring aminoglycoside and macrolide sensitivity by reversion of this mutation to the wild-type sequence. Our study demonstrates that alternative B. pseudomallei selective media without gentamicin are needed for accurate melioidosis laboratory diagnosis in Sarawak. This finding may also have implications for environmental sampling of other locations to test for B. pseudomallei endemicity.

BackgroundMelioidosis is a serious, and potentially fatal community-acquired infection endemic to northern Australia and Southeast Asia, including Sarawak, Malaysia. The disease, caused by the usually intrinsically aminoglycoside-resistant Burkholderia pseudomallei, most commonly affects adults with predisposing risk factors. There are limited data on pediatric melioidosis in Sarawak.MethodsA part prospective, part retrospective study of children aged <15 years with culture-confirmed melioidosis was conducted in the 3 major public hospitals in Central Sarawak between 2009 and 2014. We examined epidemiological, clinical and microbiological characteristics.FindingsForty-two patients were recruited during the 6-year study period. The overall annual incidence was estimated to be 4.1 per 100,000 children <15 years, with marked variation between districts. No children had pre-existing medical conditions. Twenty-three (55%) had disseminated disease, 10 (43%) of whom died. The commonest site of infection was the lungs, which occurred in 21 (50%) children. Other important sites of infection included lymph nodes, spleen, joints and lacrimal glands. Seven (17%) children had bacteremia with no overt focus of infection. Delays in diagnosis and in melioidosis-appropriate antibiotic treatment were observed in nearly 90% of children. Of the clinical isolates tested, 35/36 (97%) were susceptible to gentamicin. Of these, all 11 isolates that were genotyped were of a single multi-locus sequence type, ST881, and possessed the putative B. pseudomallei virulence determinants bimABp, fhaB3, and the YLF gene cluster.ConclusionsCentral Sarawak has a very high incidence of pediatric melioidosis, caused predominantly by gentamicin-susceptible B. pseudomallei strains. Children frequently presented with disseminated disease and had an alarmingly high death rate, despite the absence of any apparent predisposing risk factor.

Misidentifications of Burkholderia pseudomallei as Burkholderia cepacia by Vitek 2 have occurred. Multidimensional scaling ordination of biochemical profiles of 217 Malaysian and Australian B. pseudomallei isolates found clustering of misidentified B. pseudomallei isolates from Malaysian Borneo. Specificity of B. pseudomallei identification in Vitek 2 and potentially other automated identification systems is regionally dependent.

We performed a cross-sessional study of all systemic lupus erythematosus (SLE) pregnancies during a 4-year period (2006-2009) to describe the clinical features, maternal and foetal outcomes in our centre. There were 48 pregnancies in 44 women with SLE. Our patients have a mean age of 30.0 years (SD 6.36) and a mean disease duration of 40.67 months (SD 48.23). Our patients have complicated pregnancies: 32.7% have SLE flares, 17.3% have preeclampsia and 48.9% needed caesarean sections. There were 20.0% foetal losses and 17.8% preterm deliveries in our patients. SLE flares contributed to 60.0% of foetal losses in our patients. Lupus pregnancies in our centre generally have a good maternal and foetal outcome comparable to developed countries in Asia. The low incidence of APS, the high usage of hydroxychloroquine and the high SLE remission rate in our patients prior to conceptions contributed to the good outcome.

We performed a retrospective study of all systemic lupus erythematosus (SLE) pregnancies during a two-year period (2006-2007) to describe the clinical features, maternal and foetal outcomes in our centre. There were 17 pregnancies in 16 women with SLE. Our patients have a mean age of 28.31 years (SD 5.24) and a mean disease duration of 38.62 months (SD 38.03). Our patients have complicated pregnancies: 35.3% have SLE flares, 21.1% have preeclampsia and 47.4% needed caesarean sections. There were 15.8% foetal losses and 12.5% preterm deliveries in our patients. All the foetal losses occurred in patients with severe SLE flares during pregnancies. Lupus pregnancies in our centre generally have a good maternal and foetal outcome comparable with developed countries. The low incidence of antiphospholipid syndrome, the high usage of hydroxychloroquine and the high SLE remission rate in our patients before conceptions are the possible factors contributing to the good outcome.