Microbiological understandings and mysteries of noma (cancrum oris)

Current research progress on Prevotella intermedia and associated diseases

Prevotella intermedia is a Gram-negative anaerobic bacterium that is a common pathogen of periodontitis. Recent studies have revealed that P. intermedia is closely associated with a variety of diseases involving multiple systems. Under the action of its virulence factors such as cysteine protease and adhesins, P. intermedia has the ability to bind and invade various host cells including gingival fibroblasts. It can also copolymerize a variety of pathogenic bacteria, leading to interference with the host's immune inflammatory response and causing various diseases. In this article, we review the progress of research on P. intermedia virulence factors and bacterial pathogenesis, and the correlation between P. intermedia and various diseases.

Noma in an 18 months Toddler: A Rare Case Report with Review of Literature

Introduction

Noma is a polymicrobial necrotizing infection of the mouth and face which destroys the soft and hard tissues of the oral and paraoral structures. Malnutrition, poverty, lack of basic hygiene, and chronic disease state etc., possess a risk of developing noma. Noma neonatorum is a progressive gangrenous disease affecting the premature infants.

Aim

We present a rare case of noma in an 18 months toddler with a chronic debilitating condition predisposing to the disease progression.

Results

The necrotizing infection of the face developed after six months of multiple episodes of chronic blood-tinged diarrhea. The facial defect was managed with release of fibrosis and reconstruction with a superiorly based nasolabial flap.

Discussion

Noma reflects extreme malnutrition and poverty with a vast range of etiopathological agents. This case emphasizes the need to understand the host risk factors and etiopathologic agent predisposing to this rare opportunistic and dormant but devastating disease, the morbidities associated with it and measures to prevent it.

Noma Masquerading as Squamous Cell Carcinoma - A Case Report in an AIDS Patient

Rationale

Cancrum oris, also known as noma, is a rare and rapidly progressing gangrenous infection affecting the oral cavity, commonly seen in malnourished children. We discuss the clinical presentation, diagnostic dilemma and management in a 54-year-old male human immunodeficiency virus-positive patient with oral ulceration clinically resembling squamous cell carcinoma (SCC).

Patient Concerns

The patient had severe oral ulceration with pain and difficulty eating food.

Diagnosis

Histopathological examination was misleading as it revealed features akin to early invasion of SCC. Immunohistochemistry findings were not in favour of SCC.

Treatment

Antiretroviral therapy was started owing to the decreased CD4 cell count.

Outcomes

Lesions began to show signs of healing on follow-up.

Take-away Lessons

This case aims to highlight the unique challenges of diagnosing and emphasises the importance of considering opportunistic infections in immunocompromised patients presenting with oral ulcerations to prevent misdiagnosis and maltreatment.

Insertional Inactivation and Gene Complementation of Prevotella intermedia Type IX Secretion System Reveals Its Indispensable Roles in Black Pigmentation, Hemagglutination, Protease Activity of Interpain A, and Biofilm Formation

Prevotella intermedia, a Gram-negative oral anaerobic bacterium, is frequently isolated from the periodontal pockets of patients with chronic periodontitis. In recent years, the involvement of the bacterium in respiratory tract infections as well as in oral infections has been revealed. P. intermedia possesses several potent virulence factors, such as cysteine proteinase interpain A encoded by the inpA gene. The genome of P. intermedia carries genes of the type IX secretion system (T9SS), which enables the translocation of virulence factors across the outer membrane in several pathogens belonging to the phylum Bacteroidetes; however, it is still unclear whether the T9SS is functional in this microorganism. Recently, we performed targeted mutagenesis in the strain OMA14 of P. intermedia. Here, we successfully obtained mutants deficient in inpA and the T9SS component genes porK and porT. None of the mutants exhibited protease activity of interpain A. The porK and porT mutants, but not the inpA mutant, showed defects in colony pigmentation, hemagglutination, and biofilm formation. We also obtained a complemented strain for the porK gene that recovered all the above abilities. These results indicate that T9SS functions in P. intermedia and that interpain A is one of the T9SS cargo proteins. IMPORTANCE The virulence factors of periodontal pathogens such as Prevotella intermedia have not been elucidated. Using our established procedure, we succeeded in generating type IX secretion system mutants and gene complementation strains that might transfer virulence factors to the bacterial surface. The generated strains clearly indicate that T9SS in P. intermedia is essential for colonial pigmentation, hemagglutination, and biofilm formation. These results indicated that interpain A is a T9SS cargo protein.

Noma, a neglected disease: prevention is better than cure

PURPOSE OF REVIEW

There is a need for concerted effort to increase Global awareness about noma (cancrum oris). This paper aims to summarize the recent literature on noma and provide suggestions that could be implemented to raise awareness about this neglected disease.

RECENT FINDINGS

Noma has been recognized, diagnosed and reported for centuries. Despite significant progress in scientific methods over time, the published literature on noma has predominantly been of low level clinical and scientific evidence. Recent studies have reported on noma's global distribution and its predisposing risk factors, its treatment, its knowledge and beliefs and has included a number of literature reviews. Noma cases are being reported from an increasingly diverse set of geographical locations.

SUMMARY

Noma has largely been neglected in the research sphere. Noma is a preventable disease and its progression can be halted if patients are recognized and treated in the early stages of disease. Treatment for late stage noma survivors remains complex and time consuming, requiring substantial human and financial resources most commonly not achieving functional and cosmetic anatomy. The ultimate aim is therefore prevention, initiatives should be integrated into existing health programs.

Noma: A Neglected Area for Research

Noma, a debilitating and destructive orofacial gangrene, remains endemic in the poor countries of sub-Saharan Africa and other noma hotbeds across the globe, mainly in countries characterized as underdeveloped economies with significant impoverished populations. Noma mostly affects children and infants. This is in spite of the universally held notion that noma is a preventable disease. Indeed, the current noma status quo has been cast as a human rights shortfall, since this devasting disease overwhelmingly affects children from poor countries. At the recently held Noma Research Day, a renewed call for the World Health Organization (WHO) to recognize and include noma as one of the neglected tropical diseases was accompanied by a recognition that research into all aspects of noma has waned or remained completely lacking-particularly that which addresses the basic science questions of the etiology, pathophysiology/pathobiology, and underlying mechanisms of the disease. Yet, a lack of incremental knowledge on the various aspects of noma continues to hamper our composite understanding of its biology. Without a fundamental understanding of the biology of noma, current preventive measures and treatment modalities will continue to fall short of the goals of prevention and eradication. This opinion piece draws renewed attention to the urgency of listing noma as a neglected tropical disease by the WHO. It also calls for major international research funding agencies, including the WHO and the National Institutes of Health, to renew their resolve to robustly fund structured, collaborative, and coordinated proposals that address questions on the epidemiology, etiology, pathophysiology/pathobiology, and molecular mechanisms of the disease. This is with a view to achieving more effective public health approaches toward prevention and to designing potential therapeutic regimens for early lesions. These steps are key to the ultimate eradication of noma.

Noma – a neglected disease of malnutrition and poor oral hygiene: A mini-review

Objectives:

The aim of this review was to describe malnutrition and poor oral hygiene, the most common risk factors for noma.

Methods:

A vigorous literature searches were conducted on databases such as Scopus, Elsevier, Web of Science, PubMed, Virtual Health Library, and Google Scholar by inserting keywords such as ‘noma’ OR ‘cancrum oris’ OR ‘cancrum oris cases’. A total of 65 articles gathered. Of these, 38 articles found to be eligible for this study.

Results:

A total of 38 full-length articles were included in the review. According to the evidence gathered and summarized in this review, malnutrition, especially protein-energy malnutrition and vitamin deficiencies, makes the oral mucosa susceptible to opportunistic pathogens of noma, and then, in so doing, pathogens invade the oral cavities. Malnutrition has a bidirectional relationship with noma. Since noma is a disease of the oral cavity, poor oral hygiene has the potential of predispose and worsen the disease’s progress.

Conclusion:

Malnutrition and poor oral hygiene found to be ingrained in the pathogenesis of noma. For effective management and prevention of noma, it is necessary to underpin adequate nutritional supplementation (including vitamins). As a primary prevention strategy, healthcare workers’ training should be strengthened to improve the diagnosis and treatment of oral infections, including noma.

Noma (cancrum oris): A scoping literature review of a neglected disease (1843 to 2021)

Background

Noma (cancrum oris) is an ancient but neglected and poorly understood preventable disease, afflicting the most disenfranchised populations in the world. It is a devastating and often fatal condition that requires urgent and intensive clinical and surgical care, often difficult to access as most cases of noma occur in resource-limited settings. We conducted a scoping review of the literature published on noma to understand the size and scope of available research on the disease and identify research gaps that need to be addressed to evolve our understanding of how to address this disease.

Methods

We searched 11 databases and collected primary peer reviewed articles on noma in all languages, the final search was conducted on 24^th August 2021. The oldest manuscript identified was from 28^th March 1843 and the most recently published manuscript was from 3^rd June 2021. Search terms included cancrum oris and noma. Data was extracted using a standardised data extraction tool and key areas of interest were identified. The Preferred Reporting Items for Systemic review and Meta-Analyses requirements were followed.

Results

The review included 147 articles, the majority of the studies (n = 94, 64%) were case reports. Most manuscripts (n = 81, 55%) were published in the 2000s, 49 (33%) were from the 1900s and 17 (12%) from the 1800s. The main areas of interest identified were the history and epidemiology of the disease, noma’s clinical progression and aetiology, treatment regimens, mortality rates and the risk factors for the development of noma.

Conclusions

Noma has been reported in the literature for hundreds of years; however important gaps in our understanding of the disease remain. Future research should focus on determining the burden and distribution of disease; the true mortality rate, pathogenic cause(s) and the factors that influence prognosis and outcomes after treatment.

Noma is a devastating and often fatal condition that mainly affects children in severely disenfranchised communities. Noma is preventable and requires urgent basic medical care in the early stages of disease. Once the disease reaches the last stage, sequelae, survivors require expert surgical care, usually difficult to access as most cases of noma occur in resource-limited settings. We conducted a scoping review of the literature published on noma to understand the size and scope of available research on the disease and to identify research priorities that will evolve our understanding of how to eradicate this disease. Our review showed that noma has been reported in the literature for hundreds of years; however several major gaps in knowledge still exist. There is appreciation among the small community of clinicians and researchers involved in noma care and research that these gaps in knowledge impact on the ability to develop and implement sound evidence-based policies and activities aimed at eradicating noma from communities that continue to be afflicted by this ancient disease. The main focus of future research should be to study the burden and distribution of disease; the true mortality rate, and the pathogenic cause(s) and the factors that influence prognosis and outcomes after treatment.

Model of care, Noma Children's Hospital, northwest Nigeria

The Nigerian Ministry of Health has been offering care for noma patients for many years at the Noma Children’s Hospital (NCH) in Sokoto, northwest Nigeria, and Médecins Sans Frontières has supported these initiatives since 2014. The comprehensive model of care consists of four main components: acute care, care for noma sequelae, integrated hospital‐based services and community‐based services. The model of care is based on the limited evidence available for prevention and treatment of noma and follows WHO’s protocols for acute patients and best practice guidelines for the surgical treatment of noma survivors. The model is updated continually as new evidence becomes available, including evidence generated through the operational research studies performed at NCH. By describing the model of care, we wish to share the lessons learned with other actors working in the noma and neglected tropical disease sphere in the hope of guiding programme development.

Outcomes at 18 mo of 37 noma (cancrum oris) cases surgically treated at the Noma Children's Hospital, Sokoto, Nigeria

Background

Noma is a rapidly progressing infection of the oral cavity frequently resulting in severe facial disfigurement. We present a case series of noma patients surgically treated in northwest Nigeria.

Methods

A retrospective analysis of routinely collected data (demographics, diagnosis and surgical procedures undergone) and in-person follow-up assessments (anthropometry, mouth opening and quality of life measurements) were conducted with patients who had surgery >6 mo prior to data collection.

Results

Of the 37 patients included, 21 (56.8%) were male and 22 (62.9%) were aged >6 y. The median number of months between last surgery and follow-up was 18 (IQR 13, 25) mo. At admission, the most severely affected anatomical area was the outer cheek (n = 9; 36.0% of patients had lost between 26% and 50%). The most frequent surgical procedures were the deltopectoral flap (n = 16; 43.2%) and trismus release (n = 12; 32.4%). For the eight trismus-release patients where mouth opening was documented at admission, all had a mouth opening of 0–20 mm at follow-up. All patients reported that the surgery had improved their quality of life.

Conclusions

Following their last surgical intervention, noma patients do experience some improvements in their quality of life, but debilitating long-term sequelae persist.

Insertional Inactivation of Prevotella intermedia OxyR Results in Reduced Survival with Oxidative Stress and in the Presence of Host Cells

One of the most abundant bacteria in the subgingival pockets of patients with bleeding following mechanical periodontal therapy is Prevotella intermedia. However, despite its abundance, the molecular mechanisms of its contribution to periodontal disease are not well known. This is mainly due to the lack of genetic tools that would allow examination of the role of predicted virulence factors in the pathogenesis of this bacterium. Here, we report on the first mutant in the P. intermedia OMA14 strain. The mutation is an allelic exchange replacement of the sequences coding for a putative OxyR regulator with ermF sequences coding for the macrolide-lincosamide resistance in anaerobic bacteria. The mutant is severely impaired in its ability to grow with eukaryotic cells, indicating that it is an important target for interventional strategies. Further analyses reveal that its ability to grow with oxidative stress species, in the form of hydrogen peroxide and oxygen, is severely affected. Transcriptome analysis reveals that the major deregulated genes code for the alkylhydroperoxide reductase system, AhpCF, mediating protection from peroxide stress. Moreover, genes coding for Dps, CydA and Ftn are downregulated in the mutant strain, as further verified using qRT-PCR analysis. In conclusion, we succeeded in generating the first P. intermedia mutant and show that the OxyR-deficient strain is unable to survive with a variety of host cells as well as with oxidative stress.

Subgingival microbiome dynamic alteration associated with necrotizing periodontal disease: A case report

RATIONALE

Necrotizing periodontal diseases (NPDs) are a group of infectious diseases varying in severity, and microorganisms are responsible for these diseases. Currently, the oral microbiota in early disease has been poorly investigated; thus, the causative pathogen and dynamic alteration of the microbiome in NPDs remain unclear.

PATIENT CONCERNS

We report a case of a 33-year-old female patient with severe gingival pain and localized necrotizing ulcerative gingival lesions. Conventional therapy was performed, but the necrotizing lesion continued to develop.

DIAGNOSES

X-ray examination showed marginal alveolar bone loss in the involved teeth. Histological examination of a biopsy from the gingival lesion showed chronic inflammatory cell infiltration in the tissue, and no cancer cells were observed. Subgingival swabs were taken from the ulcerative gingiva and the gingiva that was not yet affected, and the composition of the microbiota was analyzed by targeted pyrosequencing of the V3-V4 hypervariable regions of the small subunit ribosomal RNA. We found that Neisseria spp., Corynebacterium spp., and Prevotella spp. were clearly enriched in the lesion site. However, Fusobacteria was more abundant in the not-yet-affected gingiva, and Leptotrichia spp. were the most abundant phylotype.

INTERVENTIONS

After clinical assessment, a tooth with poor prognosis was extracted, and minocycline hydrochloride was locally administered in the involved tooth pocket every day. Additionally, the patient received 100 mg of hydrochloric acid doxycycline twice per day.

OUTCOMES

Remarkable improvement was obtained after 3 days, and the lesion completely healed after 1 week. The follow-up examination 1 year later showed a complete recovery with no recurrent episodes of pain.

LESSONS

Changes in the subgingival microbiome can occurr before clinical symptoms appears, and Fusobacteria may be involved in the imbalance of the subgingival flora in the early stage of NPDs. Moreover, Neisseria is a potential bacterial candidate that deserves further study.

Staged lower lip reconstruction following gangrenous stomatitis in an immunosuppressed patient

A 70-year-old male with a history of diabetes mellitus, hypertension, and coronary stent insertion visited our hospital 7 days after biting his lower lip. Swelling and inflammation had worsened despite debridement and antibiotic treatment. On the 8th hospital day, fungal infection with Candida albicans and superimposed bacterial infection with Klebsiella pneumoniae were found on tissue culture. Extensive necrosis resulted in a defect of approximately 3/4 of the entire lower lip and a full-layer skin defect from the vermilion to the gingivobuccal sulcus at the right corner of the mouth. To correct drooling, incomplete lip sealing, and trismus, staged reconstruction was performed with consideration of cosmetic and functional features. The treatment process using staged reconstruction and antifungal treatment for an extensive lower lip defect caused by fungal stomatitis is described.

Distinct shifts in the oral microbiota are associated with the progression and aggravation of mucositis during radiotherapy

BACKGROUND AND PURPOSE

Oral mucositis remains one of the most common complications of radiation therapy for patients with head and neck cancer. This study aimed to investigate the dynamic shifts in the oral mucosal microbiota and their association with the progression and aggravation of mucositis in patients with nasopharyngeal carcinoma (NPC) undergoing radiotherapy.

MATERIALS AND METHODS

In this study, oropharyngeal mucosa of patients were examined regularly, and sampled longitudinally in eight stages of their radiation treatment program: before radiation, and then after 10, 20, 30, 40, 50, 60, and 70 Gy. Based on 16S rRNA gene sequencing and bioinformatics analysis, the characteristics of dynamic variations in oral microbiota during their treatment were investigated.

RESULTS

The results showed that the mucosal bacterial alpha diversity (richness and evenness) did not change significantly during the entire course of these patient treatments. Notwithstanding 20 genera were found to be significantly positively associated with their radiation dose, whereas 10 genera were negatively associated with it. Notably, two bacterial co-abundance groups (CAG 1 and 2) were identified and the majority of bacteria clustered within the CAG 2 were indeed periodontal disease-associated genera. Most strikingly, many of them, especially Prevotella, Fusobacterium, Treponema and Porphyromonas, showed obvious dynamic synchronous variations in their abundances throughout the course of radiation therapy, where their peaks frequently coincided with the onset of severe mucositis.

CONCLUSION

Our results suggest that dysbiosis of oral mucosal microbiota may contribute to exacerbating the severity of mucositis in patients undergoing radiotherapy for nasopharyngeal carcinoma.

Noma: Overview of a Neglected Disease and Human Rights Violation

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.

Cancrum Oris (Noma): The Role of Nutrition in Management

Cancrum oris (noma) is caused by the spirochete Borrelia vincenti in association with anaerobic bacteria, commonly a member of the fusobacteria. The disease occurs in deprived and undernourished individuals with poor hygiene. We present a case of clinically diagnosed cancrum oris in a 2-year old child in sub-saharan Africa that was conservatively managed by wound care and hyperalimentation. As the underlying factor and cause of mortality from noma is the immune depression of malnutrition, the role of active nutrition or hyperalimentation in the management of noma is extremely important.

In Vitro Effects of Polyphosphate against Prevotella intermedia in Planktonic Phase and Biofilm

Polyphosphate (polyP) has gained a wide interest in the food industry due to its potential as a decontaminating agent. In this study, we examined the effect of sodium tripolyphosphate (polyP3; Na5P3O10) against planktonic and biofilm cells of Prevotella intermedia, a major oral pathogen. The MIC of polyP3 against P. intermedia ATCC 49046 determined by agar dilution method was 0.075%, while 0.05% polyP3 was bactericidal against P. intermedia in time-kill analysis performed using liquid medium. A crystal violet binding assay for the assessment of biofilm formation by P. intermedia showed that sub-MICs of polyP3 significantly decreased biofilm formation. Under the scanning electron microscope, decreased numbers of P. intermedia cells forming the biofilms were observed when the bacterial cells were incubated with 0.025% or higher concentrations of polyP3. Assessment of biofilm viability with LIVE/DEAD staining and viable cell count methods showed that 0.05% or higher concentrations of polyP3 significantly decreased the viability of the preformed biofilms in a concentration-dependent manner. The zone sizes of alpha-hemolysis formed on horse blood agar produced by P. intermedia were decreased in the presence of polyP3. The expression of the genes encoding hemolysins and the genes of the hemin uptake (hmu) locus was downregulated by polyP3. Collectively, our results show that polyP is an effective antimicrobial agent against P. intermedia in biofilms as well as planktonic phase, interfering with the process of hemin acquisition by the bacterium.

In vitro effects of N-acetyl cysteine alone and in combination with antibiotics on Prevotella intermedia

N-acetyl cysteine (NAC) is an antioxidant that possesses anti-inflammatory activities in tissues. In the field of dentistry, NAC was demonstrated to prevent the expression of LPS-induced inflammatory mediators in phagocytic cells and gingival fibroblasts during the inflammatory process, but the effect of NAC on oral pathogens has been rarely studied. Here, we examined the effect of NAC against planktonic and biofilm cells of Prevotella intermedia, a major oral pathogen. NAC showed antibacterial activity against the planktonic P. intermedia with MIC value of 3 mg/ml and significantly decreased biofilm formation by the bacterium even at sub MIC. NAC did not affect the antibiotic susceptibility of planktonic P. intermedia, showing indifference (fractional inhibitory concentration index of 0.5-4) results against the bacterium in combination with ampicillin, ciprofloxacin, tetracycline or metronidazole. On the other hand, viability of the pre-established bacterial biofilm exposed to the antibiotics except metronidazole was increased in the presence of NAC. Collectively, NAC may be used for prevention of the biofilm formation by P. intermedia rather than eradication of the pre-established bacterial biofilm. Further studies are required to explore antibacterial and anti-biofilm activity of NAC against mixed population of oral bacteria and its modulatory effect on antibiotics used for oral infectious diseases.

Comparative genome analysis of Prevotella intermedia strain isolated from infected root canal reveals features related to pathogenicity and adaptation

Background

Many species of the genus Prevotella are pathogens that cause oral diseases. Prevotella intermedia is known to cause various oral disorders e.g. periodontal disease, periapical periodontitis and noma as well as colonize in the respiratory tract and be associated with cystic fibrosis and chronic bronchitis. It is of clinical significance to identify the main drive of its various adaptation and pathogenicity. In order to explore the intra-species genetic differences among strains of Prevotella intermedia of different niches, we isolated a strain Prevotella intermedia ZT from the infected root canal of a Chinese patient with periapical periodontitis and gained a draft genome sequence. We annotated the genome and compared it with the genomes of other taxa in the genus Prevotella.

Results

The raw data set, consisting of approximately 65X-coverage reads, was trimmed and assembled into contigs from which 2165 ORFs were predicted. The comparison of the Prevotella intermedia ZT genome sequence with the published genome sequence of Prevotella intermedia 17 and Prevotella intermedia ATCC25611 revealed that ~14% of the genes were strain-specific. The Preveotella intermedia strains share a set of conserved genes contributing to its adaptation and pathogenic and possess strain-specific genes especially those involved in adhesion and secreting bacteriocin. The Prevotella intermedia ZT shares similar gene content with other taxa of genus Prevotella. The genomes of the genus Prevotella is highly dynamic with relative conserved parts: on average, about half of the genes in one Prevotella genome were not included in another genome of the different Prevotella species. The degree of conservation varied with different pathways: the ability of amino acid biosynthesis varied greatly with species but the pathway of cell wall components biosynthesis were nearly constant. Phylogenetic tree shows that the taxa from different niches are scarcely distributed among clades.

Conclusions

Prevotella intermedia ZT belongs to a genus marked with highly dynamic genomes. The specific genes of Prevotella intermedia indicate that adhesion, competing with surrounding microbes and horizontal gene transfer are the main drive of the evolution of Prevotella intermedia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1272-3) contains supplementary material, which is available to authorized users.

Noma affected children from Niger have distinct oral microbial communities based on high-throughput sequencing of 16S rRNA gene fragments

We aim to understand the microbial ecology of noma (cancrum oris), a devastating ancient illness which causes severe facial disfigurement in>140,000 malnourished children every year. The cause of noma is still elusive. A chaotic mix of microbial infection, oral hygiene and weakened immune system likely contribute to the development of oral lesions. These lesions are a plausible entry point for unidentified microorganisms that trigger gangrenous facial infections. To catalog bacteria present in noma lesions and identify candidate noma-triggering organisms, we performed a cross-sectional sequencing study of 16S rRNA gene amplicons from sixty samples of gingival fluid from twelve healthy children, twelve children suffering from noma (lesion and healthy sites), and twelve children suffering from Acute Necrotizing Gingivitis (ANG) (lesion and healthy sites). Relative to healthy individuals, samples taken from lesions in diseased mouths were enriched with Spirochaetes and depleted for Proteobacteria. Samples taken from healthy sites of diseased mouths had proportions of Spirochaetes and Proteobacteria that were similar to healthy control individuals. Samples from noma mouths did not have a higher abundance of Fusobacterium, casting doubt on its role as a causative agent of noma. Microbial communities sampled from noma and ANG lesions were dominated by the same Prevotella intermedia OTU, which was much less abundant in healthy sites sampled from the same mouths. Multivariate analysis confirmed that bacterial communities in healthy and lesion sites were significantly different. Several OTUs in the Orders Erysipelotrichales, Clostridiales, Bacteroidales, and Spirochaetales were identified as indicators of noma, suggesting that one or more microbes within these Orders is associated with the development of noma lesions. Future studies should include longitudinal sampling of viral and microbial components of this community, before and early in noma lesion development.

Noma is a traumatic disease characterized by oral-facial lesions that often lead to severe disfigurement and ultimately shame and isolation from the community. Because the causes of noma are likely to be numerous, and reaching those who suffer from this illness is challenging, the etiology of noma remains ill-defined. Although it is known that oral hygiene and nutrition influence the development of noma, evidence suggests that one or more microbes play a crucial role in development of noma lesions. Previous studies have examined the DNA of microbes in lesions to determine which species are present and how their abundances differ between healthy mouth sites and noma lesions. These studies used techniques that were state-of-the-art at the time, though we know they likely only scratched the surface of the resident microbial diversity. Here we extend these studies by digging deeper to characterize a larger diversity of microbial species in noma and control samples, with the goal of better identifying which microbes are uniquely present or have altered abundances in noma lesions.

Interaction of Prevotella intermedia strain 17 leucine-rich repeat domain protein AdpF with eukaryotic cells promotes bacterial internalization

Prevotella intermedia is an oral bacterium implicated in a variety of oral diseases. Although internalization of this bacterium by nonphagocytic host cells is well established, the molecular players mediating the process are not well known. Here, the properties of a leucine-rich repeat (LRR) domain protein, designated AdpF, are described. This protein contains a leucine-rich region composed of 663 amino acid residues, and molecular modeling shows that it folds into a classical curved solenoid structure. The cell surface localization of recombinant AdpF (rAdpF) was confirmed by electron and confocal microscopy analyses. The recombinant form of this protein bound fibronectin in a dose-dependent manner. Furthermore, the protein was internalized by host cells, with the majority of the process accomplished within 30 min. The internalization of rAdpF was inhibited by nystatin, cytochalasin, latrunculin, nocodazole, and wortmannin, indicating that microtubules, microfilaments, and signal transduction are required for the invasion. It is noteworthy that preincubation of eukaryotic cells with AdpF increased P. intermedia 17 internalization by 5- and 10-fold for HeLa and NIH 3T3 fibroblast cell lines, respectively. The addition of the rAdpF protein was also very effective in inducing bacterial internalization into the oral epithelial cell line HN4, as well as into primary cells, including human oral keratinocytes (HOKs) and human umbilical vein endothelial cells (HUVECs). Finally, cells exposed to P. intermedia 17 internalized the bacteria more readily upon reinfection. Taken together, our data demonstrate that rAdpF plays a role in the internalization of P. intermedia 17 by a variety of host cells.

Noma (cancrum oris) in the South African context

Noma (cancrum oris) is a destructive necrotising disease affecting orofacial tissues predominantly of malnourished young children. It is characterised by a rapid acute onset which usually starts in the mouth, spreads intra-orally destroying soft tissue and bone and progresses to perforate the facial skin, causing disfigurement. Polybacterial anaerobic infection is critical too, but is not alone sufficient for the initiation of noma. Cofactors, first and foremost malnutrition, but also systemic viral and bacterial infections are crucial to the development of noma. A patient with necrotising stomatitis or noma must be admitted to hospital for antibiotic treatment, fluid and electrolytes as well as nutritional supplementation and general supportive treatment. The epidemiology of noma in the South African population is unknown, and the clinicopathological features are poorly characterised. Although worldwide there is no evidence that HIV infection is a strong risk factor for noma, HIV infection may play a substantial role in the pathogenesis of noma in South Africa.

Noma (cancrum oris): a report of a case in a young AIDS patient with a review of the pathogenesis

Noma (cancrum oris) is a mutilating necrotising disease of the orofacial tissues. It affects predominantly debilitated malnourished children, in whom the necrotic process may cause severe damage to mid-facial structures. Its aetiopathogenesis is uncertain, but its course is fulminating, and without timely intervention the disease may be fatal. Antibiotic treatment during any stage of necrotising stomatitis and of its sequel noma can stop progression of the disease; therefore detection and treatment of early intraoral necrotising lesions whether necrotising gingivitis, necrotising periodontitis or necrotising stomatitis are critical in preventing noma. We present an extreme case of noma in a malnourished HIV-seropositive child. There was an acute necrotic process affecting both the maxilla and the mandible with denudation of bone, spontaneous exfoliation of teeth, necrotising fasciitis and myonecrosis which destroyed the lips and cheeks and extended to the infra-orbital margins. There was severe disfigurement and severe impairment of function. Noma is primarily an anaerobic bacterial infection with secondary ischaemia leading to osteonecrosis and mid-facial destruction.

Bacterial diversity in oral samples of children in niger with acute noma, acute necrotizing gingivitis, and healthy controls

BACKGROUND

Noma 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 FINDINGS

Gingival 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.

CONCLUSIONS

Similarities 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.

NOMA: A Preventable "Scourge" of African Children

Noma is a serious orofacial gangrene originating intraorally in the gingival-oral mucosa complex before spreading extraorally to produce a visibly destructive ulcer. Although cases of noma are now rarely reported in the developed countries, it is still prevalent among children in third world countries, notably in sub-Sahara Africa, where poverty, ignorance, malnutrition, and preventable childhood infections are still common. This review summarizes historical, epidemiological, management, and research updates on noma with suggestions for its prevention and ultimate global eradication. The global annual incidence remains high at about 140,000 cases, with a mortality rate exceeding 90% for untreated diseases. Where the patients survive, noma defects result in unsightly facial disfigurement, intense scarring, trismus, oral incompetence, and social alienation. Although the etiology has long been held to be infectious, a definitive causal role between microorganisms cited, and noma has been difficult to establish. The management of noma with active disease requires antibiotics followed by reconstructive surgery. Current research efforts are focused towards a comprehensive understanding of the epidemiology, and further elucidation of the microbiology and pathogenesis of noma.Although a formidable public health challenge, noma can be prevented with a potential for subsequent global eradication. To achieve both desirable goals, detection of early disease is crucial because these early lesions respond to conventional antibiotic treatments when instituted side by side with nutritional rehabilitation, and obviates the necessity for extensive surgical reconstruction often indicated in late stage disease. The eradication of noma in the developed world in the mid 20(th) century bears out the notion of a similar outcome following effective preventive strategies in Africa. A fundamental and necessary step towards attaining this goal is for the international community to adopt a perception of noma as an urgent global public health challenge. Research effort toward deciphering the microbiology, molecular events, and pathogenesis of noma also should intensify.

Lemierre syndrome: unusual cause and presentation

Lemierre syndrome is a potentially fatal condition after an oropharyngeal infection. It is characterized by thrombophlebitis of head and neck veins with systemic dissemination of septic emboli. The most frequently isolated pathogen is Fusobacterium necrophorum. We report an unusual case of Lemierre syndrome in a 4-year-old child caused by Staphylococcus aureus, with multivisceral emboli to the brain, orbits, lungs, and heart valves. We also discuss its atypical clinical presentation, the crucial role of imaging in the early diagnosis, and the different treatment modalities of this life-threatening syndrome.

AdpC is a Prevotella intermedia 17 leucine-rich repeat internalin-like protein

The oral bacterium Prevotella intermedia attaches to and invades gingival epithelial cells, fibroblasts, and endothelial cells. Several genes encoding proteins that mediate both the adhesion and invasion processes are carried on the genome of this bacterium. Here, we characterized one such protein, AdpC, belonging to the leucine-rich repeat (LRR) protein family. Bioinformatics analysis revealed that this protein shares similarity with the Treponema pallidum LRR (LRR(TP)) family of proteins and contains six LRRs. Despite the absence of a signal peptide, this protein is localized on the bacterial outer membrane, indicating that it is transported through an atypical secretion mechanism. The recombinant form of this protein (rAdpC) was shown to bind fibrinogen. In addition, the heterologous host strain Escherichia coli BL21 expressing rAdpC (V2846) invaded fibroblast NIH 3T3 cells at a 40-fold-higher frequency than control E. coli BL21 cells expressing a sham P. intermedia 17 protein. Although similar results were obtained by using human umbilical vein endothelial cells (HUVECs), only a 3-fold-increased invasion of V2846 into oral epithelial HN4 cells was observed. Thus, AdpC-mediated invasion is cell specific. This work demonstrated that AdpC is an important invasin protein of P. intermedia 17.

Gene expression profile and pathogenicity of biofilm-forming Prevotella intermedia strain 17

BACKGROUND

Prevotella intermedia (P. intermedia), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. P. intermedia strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials in vitro from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays.

RESULTS

Strain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (sigmaE; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media.

CONCLUSION

These results demonstrate that the capacity to form biofilm in P. intermedia contribute to their resistance against host innate defence responses.

Herpesviral-bacterial synergy in the pathogenesis of human periodontitis

PURPOSE OF REVIEW

Periodontitis is an infectious disease, but the specific mechanisms by which tooth-supportive tissues are lost remain obscure. This article proposes an infectious disease model for periodontitis in which herpesviral-bacterial interactions assume a major etiopathogenic role.

RECENT FINDINGS

Epstein-Barr virus type 1, cytomegalovirus and other herpesviruses occur at a high frequency in aggressive periodontitis lesions. Also, herpesvirus-infected periodontitis lesions tend to harbor elevated levels of classic periodontopathic bacteria, including Porphyromonas gingivalis, Dialister pneumosintes, Prevotella intermedia, Prevotella nigrescens, Campylobacter rectus, Treponema denticola and Actinobacillus (Aggregatibacter) actinomycetemcomitans.

SUMMARY

Conceivably, a herpesvirus active infection in the periodontium impairs local defenses, thereby permitting overgrowth and increased aggressiveness of periodontopathic bacteria. In turn, periodontal pathogenic bacteria may augment the virulence of periodontal herpesviruses. It is suggested that interactions among herpesviruses and specific bacterial species constitute an important pathogenetic feature of periodontitis and maybe also of various non-oral infections.

Degradation of human hemoglobin by Prevotella intermedia

In this study, the ability of Prevotella intermedia, an obligate anaerobic rod, to degrade human hemoglobin was determined by SDS-PAGE and the degradation was quantified by scanning densitometry. Both bacterial cells and culture supernatants degraded hemoglobin. The hemoglobin degradation by P. intermedia was time-dependent, heat sensitive, pH related and was not influenced by iron restriction. Inhibition studies demonstrated that a cysteine protease might be involved in hemoglobin degradation and this protease might require metal ions for its activity and it might be thiol-requiring and trypsin-inducible. The results indicate that P. intermedia is capable to release heme from hemoglobin, hence provide a source of iron for its proliferation.

From a sore throat to the intensive care unit: the Lemierre syndrome

Lemierre syndrome is characterized by an acute oropharyngeal infection, suppurative thrombophlebitis of the internal jugular vein and metastatic infections. The infection is usually caused by Fusobacterium necrophorum. We report on a 19-year-old male patient who was admitted with a five-day history of fever, sore throat and progressive dyspnea. Computed tomography of the neck and chest revealed a parapharyngeal abscess, jugular vein thrombosis, descending necrotizing mediastinitis and multiple areas of bilateral consolidation and cavitations within the lungs. Fusobacterium necrophorum was identified in the blood culture. Early combined abscess drainage with neck and chest incisions, together with broad spectrum intravenous antibiotic treatment and medical management in an intensive care unit resulted in a good clinical outcome.

Noma (cancrum oris)

Noma is an opportunistic infection promoted by extreme poverty. It evolves rapidly from a gingival inflammation to grotesque orofacial gangrene. It occurs worldwide, but is most common in sub-Saharan Africa. The peak incidence of acute noma is at ages 1-4 years, coinciding with the period of linear growth retardation in deprived children. Noma is a scourge in communities with poor environmental sanitation. It results from complex interactions between malnutrition, infections, and compromised immunity. Diseases that commonly precede noma include measles, malaria, severe diarrhoea, and necrotising ulcerative gingivitis. The acute stage responds readily to antibiotic treatment. The sequelae after healing include variable functional and aesthetic impairments, which require reconstructive surgery. Noma can be prevented through promotion of national awareness of the disease, poverty reduction, improved nutrition, promotion of exclusive breastfeeding in the first 3-6 months of life, optimum prenatal care, and timely immunisations against the common childhood diseases.

Submental intubation for cancrum oris: a case report

Cancrum oris (Noma) is a devastating gangrenous disease that leads to severe tissue destruction in the face. We describe the anesthetic management of a 12-year-old girl with cancrum oris sequelae in a Rural Secondary level Hospital in Central India (Padhar Hospital). She presented with a large defect in her upper lip on the left side that extended into the columella and the floor of the left nostril. She was scheduled to undergo reconstructive surgery and the surgeons planned to use an Abbé flap based on the lower lip. For this, access to both the mouth and the nose was required. We considered a tracheostomy but decided to attempt the submental route for orotracheal intubation. Following intravenous induction the patient's trachea was intubated with a cuffed oral tracheal tube. This was passed through the submental incision and then reconnected. The surgery proceeded uneventfully and the patient was extubated before transfer. She made a satisfactory recovery and the submental scar healed without complication or scarring. We describe briefly the features of cancrum oris and review the technique of submental intubation (described in adults with midfacial trauma). The use of submental intubation in children and for cancrum oris sequelae has not been previously reported.

Temporal relationship between the occurrence of fresh noma and the timing of linear growth retardation in Nigerian children

BACKGROUND

Fresh noma (cancrum oris) occurs predominantly in children <4 years of age. The key risk factors are poverty, malnutrition and infections. Evolution from an intraoral inflammation to a grotesque oro-facial gangrene is very rapid.

OBJECTIVE

We assessed potential relationship between the occurrence of fresh noma and linear growth retardation (LGR) which is prevalent in deprived Third World infants/children between ages 3 and 30 months. LGR is attributed to malnutrition and chronic immunostimulation by environmental antigens.

DESIGN

Anthropometric evaluation of children (n = 91) with fresh noma, ages 0-8 years, in relation to US National Center for Health Statistics Reference values was carried out. Age-matched noma-free, poor village children (n = 151) from similar communities as noma cases, and elite urban children (n = 132) served as control groups. Heights and weights were measured and the height for age (HAZ), weight for age (WAZ) and weight for height (WHZ) scores calculated as indices of stunting, underweight and wasting respectively. Serum level of interleukin (IL)-18, a multifunctional cytokine, was also measured.

RESULTS

In the age groups 0-4 and 4-8 years, the percentages of noma children <-2.0SD were 91% and 67% respectively. The corresponding values for the village children were 37% and 24% and significantly different (P < 0.001) from the noma group. Only 7% of the elite children aged 4-8 years were stunted. Low body weight and wasting were prominent features of village and noma groups, but more marked in the latter. Associated with noma was a profound increase (P < 0.001) in IL-18 in comparison with urban controls, and a 34% non-statistically significant increase relative to the village control group. Among other functions, IL-18 induces several pro-inflammatory cytokines and the matrix metalloproteinases, influences long bone growth, and consequently may be relevant to growth retardation seen in poor village children and noma victims.

CONCLUSION

These results suggest that occurrence of fresh noma was probably programmed very early in life by malnutrition and chronic infections resulting from replacement of breast milk with contaminated, inferior substitutes. Although not investigated, we speculate that children with fresh noma might also be victims of intrauterine growth retardation as noma is most prevalent during the infantile phase of child growth which starts at mid-gestation and tails off at 4 years.

Update on human cytomegalovirus in destructive periodontal disease

AIM

Human cytomegalovirus (HCMV), a herpesvirus, is discussed in this review as it relates to destructive periodontal disease in humans.

RESULTS

HCMV genomic sequences, detected by polymerase chain reaction identification, occur with elevated frequency in severe adult periodontitis, localized and generalized aggressive (juvenile) periodontitis, Papillon-Lefèvre syndrome periodontitis, acute necrotizing ulcerative gingivitis, and periodontal abscesses.

DISCUSSION

Herpesviruses establish lifelong persistent infections. HCMV infection involves an asymptomatic latent phase interrupted by periods of recrudescence where viral replication and possibly clinical disease become manifest. HCMV reactivation is triggered by a number of immunosuppressive factors, some of which have been shown also to be risk factors/indicators of periodontitis. HCMV periodontal infection may cause release of tissue-destructive cytokines, overgrowth of pathogenic periodontal bacteria, and initiation of cytotoxic or immunopathologic events.

CONCLUSIONS

A growing body of data supports the concept that HCMV contributes to severe types of periodontal disease. HCMV infection of the periodontium may alter the immune control of resident microorganisms and be important in a multistage pathogenesis of periodontitis involving viral activation, periodontopathic bacteria, and host immune responses. Understanding the significance of HCMV and other herpesviruses in the development of periodontal disease may have important therapeutic implications. Vaccines against HCMV, which are in various stages of development, need to be evaluated for their ability to decrease the incidence of destructive periodontal disease.

Noma-like gangrenous cheilitis in a child with cyclic neutropenia associated with myeloperoxidase deficiency

An unusual case of cyclic neutropenia and hereditary myeloperoxidase deficiency complicated by noma-like gangrenous cheilitis is described. Klebsiella pneumoniae and Candida albicans were cultured from the involved area. We present this case to increase physician awareness of the possible association of both quantitative and qualitative defects of neutrophils and to stress the importance of the early and effective management of skin infections that can rapidly progress to severe sequelae when associated with profound neutropenia.

Noma: experiences with a microvascular approach under West African conditions

Noma (cancrum oris) is a serious ulcerating disease that generally begins in the gingival sulcus of children. One of the main areas of prevalence today is West Africa. If noma is survived, it results in disfiguring midfacial defects and intense scarring. Oral incompetence is often combined with trismus resulting from scar formation or bony fusion between the maxilla and the mandible. Reconstructive approaches with pedicled flaps from the head or shoulder area for closure of the outer defects have been prone to donor-site complications or have not properly addressed the trismus, leading to high recurrence rates. During three West African Interplast missions, a single-stage procedure was developed for reconstruction of the inner and outer linings of the oral, nasal, and paranasal cavities, with restoration of jaw function. The procedure consists of radical scar excision, placement of an external distractor for mouth opening, and primary closure of the defect with a folded free parascapular flap for full-thickness coverage. Twenty-three patients with various noma-related defects were treated with this procedure; two cases are described in detail. This combined treatment can be a safe successful procedure for patients with noma, especially those with severe soft-tissue destruction and profound trismus, even under demanding surgical conditions.

Noma: a forgotten disease

According to recent reports from the WHO, noma (or cancrum oris), a hideous, ancient disease primarily affecting children living in poverty in parts of sub-Saharan Africa, is increasing. Noma often starts as an ulcer on the oral mucosa or as ANG and commonly after a bout of measles or other disease. It quickly develops into a massive necrosis, moving from the inside outward, often involving major portions of the face. Early treatment with antibiotics, rehydration, correction of electrolytic imbalances, and administering nutritional supplements will halt the disease. The high mortality rate, however, indicates that many children are not given care or brought for care in time. Surviving victims often display severe facial deformities that demand extensive reconstructive surgery. Current research has elucidated parts of the pathogenesis of noma. The WHO started the international Action Network Against Noma in 1992, with its official launch on the World Health Day in 1994: a five-point action plan was presented and current work follows that plan.

Noma: an "infectious" disease of unknown aetiology

Noma (cancrum oris) is a devastating gangrenous disease that leads to severe tissue destruction in the face and is associated with high morbidity and mortality. It is seen almost exclusively in young children living in remote areas of less developed countries, particularly in Africa. The exact prevalence of the disease is unknown, but a conservative estimate is that 770000 people are currently affected by noma sequelae. The cause remains unknown, but a combination of several elements of a plausible aetiology has been identified: malnutrition, a compromised immune system, poor oral hygiene and a lesion of the gingival mucosal barrier, and an unidentified bacterial factor acting as a trigger for the disease. This review discusses the epidemiology, clinical features, current understanding of the pathophysiology, and treatment of the acute phase and sequelae requiring reconstructive surgery. Noma may be preventable if recognised at an early stage. Further research is needed to identify more exactly the causative agents.

Oral fungal and bacterial infections in HIV-infected individuals: an overview in Africa

Oral opportunistic infections developing secondary to human immunodeficiency virus (HIV) infection have been reported from the early days of the epidemic and have been classified by both the EC-Clearinghouse and the World Health Organisation (WHO). Among the fungal infections, oral candidiasis, presenting in African HIV-infected patients has been sporadically documented. We review the literature with respect to candidal carriage, oral candidiasis prevalence and the predictive value of oral candidiasis for a diagnosis of underlying HIV disease in African HIV-infected patients. The use of oral candidiasis as a marker of disease progression, the species of yeasts isolated from the oral cavity in Africa and the resistance of the yeasts to antifungal agents and treatment regimens are discussed. Orofacial lesions as manifestations of the systemic mycoses are rarely seen in isolation and few cases are reported in the literature from Africa. In spite of the high incidence of noma, tuberculosis, chronic osteomyelitis and syphilis in Africa, surprisingly there have been very few reported cases of the oral manifestations of these diseases in HIV-positive individuals. Orofacial disease in HIV-infected patients is associated with marked morbidity, which is compounded by malnutrition. The authors indicate specific research areas, initially directed at the most effective management strategies, which would complete data in this important area.