Gut microbiota profile of Indonesian stunted children and children with normal nutritional status.

The gut microbiota has been shown to play a role in energy metabolism of the host. Dysbiosis of the gut microbiota may predispose to obesity on the one hand, and stunting on the other. The aim of the study was to study the difference in gut microbiota composition of stunted Indonesian children and children of normal nutritional status between 3 and 5 years. Fecal samples and anthropometric measurements, in addition to economic and hygiene status were collected from 78 stunted children and 53 children with normal nutritional status in two regions in Banten and West Java provinces: Pandeglang and Sumedang, respectively. The gut microbiota composition was determined by sequencing amplicons of the V3-V4 region of the 16S rRNA gene. The composition was correlated to nutritional status and anthropometric parameters. Macronutrient intake was on average lower in stunted children, while energy-loss in the form of short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA) appeared to be higher in stunted children. In stunted children, at the phylum level the relative abundance of Bacteroidetes (44.4%) was significantly lower than in normal children (51.3%; p-value 2.55*10-4), while Firmicutes was significantly higher (45.7% vs. 39.8%; p-value 5.89*10-4). At the genus level, overall Prevotella 9 was the most abundant genus (average of 27%), and it was significantly lower in stunted children than in normal children (23.5% vs. 30.5%, respectively; q-value 0.059). Thirteen other genera were significantly different between stunted and normal children (q-value < 0.1), some of which were at low relative abundance and present in only a few children. Prevotella 9 positively correlated with height (in line with its higher relative abundance in normal children) and weight. In conclusion, Prevotella 9, which was the most abundant genus in the children, was significantly lower in stunted children. The abundance of Prevotella has been correlated with dietary fibre intake, which was lower in these stunted children. Since fibres are fermented by the gut microbiota into SCFA, and these SCFA are a source of energy for the host, increasing the proportion of Prevotella in stunted children may be of benefit. Whether this would prevent the occurrence of stunting or even has the potential to revert it, remains to be seen in follow up research.

Leptospira detection in flood-prone environment of Jakarta, Indonesia.

The study about Leptospira, particularly pathogenic strain, was conducted in the flood-prone area in the Special Capital Region of Jakarta. The aim of this study was to discover and identify the serovars of pathogenic Leptospira in the environment, which might infect human during flooding. Seventy-three samples, consisted of 36 samples of environmental water and 37 samples of soil, were collected from 5 districts of Jakarta. Their pH was measured, and the samples were then cultured in a modified Korthof's medium with 5-fluorouracil (5-FU) addition. Polymerase chain reaction, targeted on 23S rDNA (rrl), FlaB and LipL32 genes, was performed to identify Leptospira genus and differentiate the pathogenic. Identification of the pathogenic Leptospira was done utilising DNA sequencing. Seven samples showed amplification of rrl-gene. flaB and lipl32-PCR assay indicated one positive amplification band, each. Confirmation of flaB and lipl32 amplicons by DNA sequencing and BLAST analysis showed flaB amplicon (G1B; GenBank accession number MK006031.1) had 94% similarity with L. licerasiae (LC005426.1), while lipl32 amplicon was not identified as lipl32 of Leptospira. Based on those results, one intermediate pathogenic and six saprophytic Leptospira were obtained from the environment in Jakarta.

Development of immunochromatography-based methods for detection of leptospiral lipopolysaccharide antigen in urine.

Leptospirosis is an infectious disease caused by the spirochete bacteria Leptospira spp. and is commonly found throughout the world. Diagnosis of leptospirosis performed by culture and microscopic agglutination tests is laborious and time-consuming. Therefore, we aimed to develop a novel immunochromatography (ICG)-based method for detecting Leptospira antigen in the urine of patients and animals. We used the 1H6 monoclonal antibody (MAb), which is specific to the lipopolysaccharide (LPS) that is common among Leptospira spp. The MAb was coupled to 40-nm-diameter colloidal gold, and the amounts of labeled antibody and immobilized antibody were 23 µg and 2 µg per test, respectively. Several strains of Leptospira and other bacterial species were used to evaluate the sensitivities and specificities of the assays we developed. The detection limit of the assays was 10(6) cells/ml when disrupted whole bacterial cells were used. The assays were Leptospira specific since they did not cross-react with non-Leptospira bacteria used in the study. Application of diagnostic assays was done on the urine samples of 46 Leptospira-infected hamsters, 44 patients with suspected leptospirosis, and 14 healthy individuals. Pretreatment of the urine samples by boiling and centrifugation (for ultrafiltration and concentration) eliminated nonspecific reactions that occurred in the assay. The sensitivity and specificity of the ICG-based lateral flow assay (LFA) were 89% and 87%, respectively, which were higher than those of the dipstick assay, which were 80% and 74%, respectively. In summary, this ICG-based LFA can be used as an alternative diagnostic assay for leptospirosis. Further development is still necessary to improve the assay.