Nitrogen fixation associated with sago (Metroxylon sagu) and some implications.

AIMS: To determine the presence and contribution of diazotrophic bacteria to nitrogen concentrations in edible starch derived from the sago palm (Metroxylon sagu). METHODS AND RESULTS: Isolation of diazotrophic bacteria and analysis of nitrogen fixation were conducted on pith, root and sago starch samples. Acetylene reduction showed that five of ten starch samples were fixing nitrogen. Two presumptive nitrogen-fixing bacteria from starch fixed nitrogen in pure culture and five isolates were positive for the nif H gene. Nitrogen concentrations in 51 starch samples were low (37 samples <0·2 g kg(-1); 14 ranging from 0·2 to 2·0 g kg(-1)). CONCLUSIONS: Nitrogen fixation occurs in sago starch, which undoubtedly plays a role in fermentation ecology. Nitrogen levels are considered too low to be of nutritional benefit and to protect against nutritional-associated illnesses. SIGNIFICANCE AND IMPACT OF THE STUDY: Sago starch does not add significantly to the protein calorie intake and may be associated with susceptibility to nutritional-associated illness.

The epidemiology of melioidosis in the Balimo region of Papua New Guinea.

The distribution of Burkholderia pseudomallei was determined in soil collected from a rural district in Papua New Guinea (PNG) where melioidosis had recently been described, predominately affecting children. In 274 samples, 2.6% tested culture-positive for B. pseudomallei. Pulsed-field gel electrophoresis using SpeI digests and rapid polymorphic DNA PCR with five primers demonstrated a single clone amongst clinical isolates and isolates cultured from the environment that was commonly used by children from whom the clinical isolates were derived. We concluded that individuals in this region most probably acquired the organism through close contact with the environment at these sites. Burkholderia thailandensis, a closely related Burkholderia sp. was isolated from 5.5% of samples tested, an observation similar to that of melioidosis-endemic areas in Thailand. This is the first report of an environmental reservoir for melioidosis in PNG and confirms the Balimo district in PNG as melioidosis endemic.

Melioidosis in a rural community of Western Province, Papua New Guinea.

A prospective study was conducted to determine the significance of melioidosis in the Balimo district of Western Province, Papua New Guinea. During 1998, after the establishment of laboratory procedures and increasing local clinical awareness, the disease was found in 1.8% (95% CI 0.37-5.1%) of individuals presenting with fever refractory to standard treatment. The clinical incidence was 20.0 per 100,000 population (95% CI 12.2-30.9). The median age of culture-confirmed cases was 9.5 years (interquartile range 8.3-14.8 years). The seroprevalence of 747 community children in the region tested was 8.2% (95% CI 6.2-10.4%). Most individuals presented during the rainy season with a febrile disease refractory to standard treatment, sometimes mimicking tuberculosis. Some family clustering was apparent. All patients with bacteraemic melioidosis died, but treatment with the available conventional therapies of chloramphenicol, co-trimoxazole or doxycycline resulted in survival and cure in six patients with subacute/localised melioidosis. Further studies are needed to ascertain the local epidemiology and why children appear particularly at risk, as well as to establish the true extent of melioidosis in Papua New Guinea.