Mitochondrial genome diversity of Balamuthia mandrillaris revealed by a fatal case of granulomatous amoebic encephalitis

Introduction

Balamuthia (B.) mandrillaris is a free-living amoeba that can cause rare yet fatal granulomatous amoebic encephalitis (GAE). However, efficacious treatment for GAE is currently unavailable, especially when genomic studies on B. mandrillaris are limited.

Methods

In this study, B. mandrillaris strain KM-20 was isolated from the brain tissue of a GAE patient, and its mitochondrial genome was de novo assembled using high-coverage Nanopore long reads and Illumina short reads.

Results and Discussion

Phylogenetic and comparative analyses revealed a range of diversification in the mitochondrial genome of KM-20 and nine other B. mandrillaris strains. According to the mitochondrial genome alignment, one of the most variable regions was observed in the ribosomal protein S3 (rps3), which was caused by an array of novel protein tandem repeats. The repeating units in the rps3 protein tandem region present significant copy number variations (CNVs) among B. mandrillaris strains and suggest KM-20 as the most divergent strain for its highly variable sequence and highest copy number in rps3. Moreover, mitochondrial heteroplasmy was observed in strain V039, and two genotypes of rps3 are caused by the CNVs in the tandem repeats. Taken together, the copy number and sequence variations of the protein tandem repeats enable rps3 to be a perfect target for clinical genotyping assay for B. mandrillaris. The mitochondrial genome diversity of B. mandrillaris paves the way to investigate the phylogeny and diversification of pathogenic amoebae.

Prevalence and associates of obesity and overweight among school-age children in a rural community of Thailand

Purpose

Information about overweight and obesity among students in rural areas of Thailand is limited. Therefore, we aimed to determine overweight and obesity prevalences and associated factors among school-aged children in a rural community of Thailand.

Methods

We selected 9 public schools through cluster sampling in 2 provinces located in central Thailand in 2016. Anthropometric measurements were measured using standard techniques, classified as overweight (>1 standard deviation [SD]) and obese (>2 SD) with respect to their age and sex using 2007 World Health Organization reference charts. Standardized questionnaires on risk factors were sent to parents to be completed together with their child.

Results

Among 1,749 students, 8.98% had overweight and 7.26% had obesity. Mean age (range) was 11.5 years (5–18 years). Independent factors associated with overweight and obesity included primary school student (reference as secondary school) (adjusted odds ratio [aOR], 2.25; 95% confidence interval [CI], 1.24–4.08; P=0.07), mother’s body mass index (aOR, 1.07; 95% CI, 1.02–1.12; P=0.001), self-employed father (aOR, 1.99; 95% CI, 1.12–3.55; P=0.018), number of siblings (aOR, 0.61; 95% CI, 0.47–0.81; P=0.001), having sibling(s) with obesity (aOR, 1.82; 95% CI, 1.20–2.77; P=0.005), more than one (aOR, 7.16; 95% CI, 2.40–21.32; P<0.001), consuming 2–3 ladles of rice/meal (aOR, 2.14; 95% CI, 1.38–3.32; P=0.001), consuming >3 ladles of rice/meal (aOR, 2.69; 95% CI, 1.11–6.46; P= 0.27), watching <2 hours of television/day (aOR, 2.18; 95% CI, 1.19–4.01; P=0.012), and watching >2 hours of television/day (aOR, 2.60; 95% CI, 1.36–4.96; P=0.004).

Conclusion

Many sociodemographic, dietary, and behavioral factors were related to overweight and obesity among school-aged children not only in urban but also rural communities of Thailand.

Clinical epidemiology, risk factors and treatment outcomes of extended-spectrum beta-lactamase producing Enterobacteriaceae bacteremia among children in a Tertiary Care Hospital, Bangkok, Thailand

OBJECTIVE

Extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae infection is an emerging problem in paediatric populations leading to increased mortality. The purpose of this study was to determine the prevalence, risk factors and clinical outcomes of ESBL-producing Enterobacteriaceae in paediatric blood stream infections (BSIs). A retrospective review of paediatric patients diagnosed with Enterobacteriaceae bacteremia was performed at Phramongkutklao Hospital from 2010 to 2017.

RESULTS

Among 97 non-duplicated blood isolates, the prevalence of ESBL-producing Enterobacteriaceae was 53.6% (28.9% Escherichia coli and 25.8% Klebsiella spp. isolates). The study indicated that the prevalence of ESBL infection was higher among patients with chronic illness, especially hematologic malignancies, than among patients without underlying disease (P = 0.01). No differences were observed in the prior use of any antibiotics, the use of extended-spectrum cephalosporin, neutropaenia or the presence of an indwelling central venous catheter. Mortality in the ESBL group was significantly higher than that in the non-ESBL group, with observed mortalities of 38.9% and 13.3%, respectively (P < 0.05). In conclusion, BSIs with ESBL-producing Enterobacteriaceae tended to increase infection rates and impact survival rates among paediatric patients.

Methicillin-susceptible Staphylococcus aureus skin infections among military conscripts undergoing basic training in Bangkok, Thailand, in 2014

Background

Skin and soft tissue infections are common among military conscripts undergoing close-contact training activities. On June 4, 2014, an outbreak of Staphylococcus aureus skin infection was reported among military conscripts undergoing basic training in Bangkok, Thailand. An investigation was performed to verify the outbreak and recommend future prevention and control strategies.

Case presentation

The outbreak resulted in a rate of infection of 19.2 % and a fatality rate of 2.5 % (one death). All were Thai men aged 21.2 ± 1.0 years. Risk factors associated with infection were multiple erythematous papules and training in certain subunits. Randomly selected isolates were evaluated by pulsed field gel electrophoresis to confirm the clonal identity.

Conclusions

This report confirms that S. aureus skin infection can be fatal. Our study highlights the role of military personnel in the early detection, prompt treatment, and containment of outbreaks of skin infection, as well as other health issues among conscripts.