No abstract

Gertrude Hirzel Foundation.

Noma is an orofacial gangrene affecting malnourished children and mainly observed in tropical countries, particularly sub-Saharan Africa. Epidemiological data on noma are scarce, but a current estimate of the global incidence is 30,000-40,000 cases per year, with a mortality rate of approximately 85% and a burden of disease calculated to be a loss of 1-10 million disability-adjusted life years. The etiology of noma is multifactorial with malnutrition as an ever present factor, often in combination with concomitant diseases, such as measles, malaria, and human immunodeficiency virus (HIV), and poor oral hygiene. The pathogenesis is a fast-spreading, noncontagious gangrenous infection occurring in the face, often preceded by acute necrotizing gingivitis, and stomatitis. Rare microbiological studies suggest an opportunistic infection caused by an imbalance in normal intraoral microorganisms. Prevention lies in food security, measles vaccination, prevention of malaria and HIV, including the early detection and treatment of necrotizing gingivitis and stomatitis. Early treatment with antibiotics may prevent gangrene or reduce its extent. Late treatment consists of surgical rehabilitation, which is often complex. However, access to medical care is very limited for noma patients due to the extremely poor conditions in which they live that are frequently located in remote rural areas. The authors support the United Nations Human Rights Council Resolution 19/7 adopted on March 22, 2012 "The right to food," and advocate for the inclusion of noma on the list of neglected tropical diseases to encourage more medical and institutional attention for this often lethal or very mutilating infectious gangrene.

BackgroundNoma is a gangrenous disease that leads to severe disfigurement of the face with high morbidity and mortality, but its etiology remains unknown. Young children in developing countries are almost exclusively affected. The purpose of the study was to record and compare bacterial diversity in oral samples from children with or without acute noma or acute necrotizing gingivitis from a defined geographical region in Niger by culture-independent molecular methods.Methods and Principal FindingsGingival samples from 23 healthy children, nine children with acute necrotizing gingivitis, and 23 children with acute noma (both healthy and diseased oral sites) were amplified using “universal” PCR primers for the 16 S rRNA gene and pooled according to category (noma, healthy, or acute necrotizing gingivitis), gender, and site status (diseased or control site). Seven libraries were generated. A total of 1237 partial 16 S rRNA sequences representing 339 bacterial species or phylotypes at a 98–99% identity level were obtained. Analysis of bacterial composition and frequency showed that diseased (noma or acute necrotizing gingivitis) and healthy site bacterial communities are composed of similar bacteria, but differ in the prevalence of a limited group of phylotypes. Large increases in counts of Prevotella intermedia and members of the Peptostreptococcus genus are associated with disease. In contrast, no clear-cut differences were found between noma and non-noma libraries.ConclusionsSimilarities between acute necrotizing gingivitis and noma samples support the hypothesis that the disease could evolve from acute necrotizing gingivitis in certain children for reasons still to be elucidated. This study revealed oral microbiological patterns associated with noma and acute necrotizing gingivitis, but no evidence was found for a specific infection-triggering agent.

Assessing bacterial flora composition appears to be of increasing importance to fields as diverse as physiology, development, medicine, epidemiology, the environment, and the food industry. We report here the development and validation of an original microarray strategy that allows analysis of the phylogenic composition of complex bacterial mixtures. The microarray contains ϳ9,500 feature elements targeting 16S rRNA gene-specific regions. Probe design was performed by selecting oligonucleotide sequences specific to each node of the seven levels of the bacterial phylogenetic tree (domain, phylum, class, order, family, genus, and species). This approach, based on sequence information, allows analysis of the bacterial contents of complex bacterial mixtures to detect both known and unknown microorganisms. The presence of unknown organisms can be suspected and mapped on the phylogenetic tree, indicating where to refine analysis. Initial proof-of-concept experiments were performed on oral bacterial communities. Our results show that this hierarchical approach can reveal minor changes (<1%) in gingival flora content when samples collected in individuals from similar geographical origins are compared.