Question

What is the main difference between infant and adult oral microflora, and what is the cause of this difference?

can u tell me plzz

Answer 1

•To compare the oral microflora of a newborn and adult , we have to focus the journey of man from infancy to adult-

•The set of infant and childhood oral microflora go to the subsequent colonization, which will lead to more complex and stable ecosystems in adulthood. These early microbial communities, therefore, play a major role in the development of the microbiota of the adult body and may represent a source of both pathogenic and protective microorganisms in a very early stage of human life.

•oral bacteria, Archaea, fungi, parasitic, and viral colonization from birth to adulthood. Let us described each one as follows-

•Oral bacterial colonization:- the start of microflora in new born is maternal origin. Soon after birth, most newborns lacked any of the tested microorganisms in their oral cavity. Two days later, oral microorganisms were detected. A significant correlation was found between the total aerobic cultivated bacteria counts of the mothers, and of their newborns.

•In the mouth, only mucosal surfaces are available during the first months of life. After teeth emerge, the number of attachment sites and potential niches increases significantly. Bacteria adhere not only to oral surfaces but also to each other, forming multigeneric communities where specific partner relationships influence their composition and stability.

• Viridans streptococci and Fusobacterium nucleutum [a strictly anaerobic species],are example of this .

• The oral colonization pattern differs between individuals already in infancy; variable bacterial load in saliva of attendants and other close contacts and the frequency of this bacterial exposure may partly account for individual differences. In addition, the exposure of an infant to antibiotics affects the quality of colonizing bacteria.

•Staphylococcus species are an important cause of systemic infections among children S. aureus, S. epidermidis and S. warneri.

•Babies born by vaginal birth have similar bacterial communities to the mother's vaginal bacterial communities; predominantly Lactobacillus, Prevotella, and Sneathia spp., While babies born by Cesarean section (dystocic) have bacterial communities similar to those present in the mother's skin, predominantly Staphylococcus, Corynebacterium, and Propionibacterium spp.

•As the child grows the proportion of periopathogenic bacteria increase. There is a change in the bacterial population from aerobic or facultative gram-positive cocci to anaerobic fastidious gram-negative bacteria. With regard to health, children's oral cavities have a higher proportion of bacteria from the phyla Firmicutes (genus Streptococcus, Veillonella, Lactobacillus, and Granulicatella) and Actinobacteria (Rothia and Actinomyces genera), and a smaller proportion of bacteria from the phyla Bacteroidetes (genus Prevotella and order Bacteroidales), Fusobacteria (genus Fusobacterium), Spirochaetes, and candidate division TM7, in comparison to adults. Puberty is a time of major hormonal changes, which is accompanied by nutritional enrichment of the oral environment. Commonly, this phenomenon leads to an increase in some groups of oral microorganisms, including gram-negative anaerobes and spirochetes.[40] This change in the oral microbiota may be associated with the increased incidence and severity of gingivitis during puberty.

•During adult hood the microflora is totally dependent on the food eating habit, smoking, alcohol intake ,and cleanliness and care of oral cavity. The increased consumption of fermentable carbohydrates can induce a change, with the oral microbiota favoring the growth of aciduric and acidogenic species. In accordance, poor oral health and dental care, tooth loss, and a history of periodontitis are considered risk factors for cancer development in the oral cavity or other body sites .In addition, several oral microorganisms, including the commonly encountered oral Streptococci (and yeasts), possess metabolic pathways for the conversion of alcohol to carcinogenic acetaldehyde . Similarly, smoking also causes an increase in salivary acetaldehyde concentrations, hence adding to the risk related to alcohol, thus making the effects of smoking and alcohol consumption on cancer development synergistic.

•Virus, are also recognized etiological agents of cancer; the Human Papilloma Virus (HPV) being of particular relevance in the oral cavity.

•Oral Archaea colonization:-

Archaea represent a small minority of the oral microbiome, which are restricted to a small number of methanogenic species/phylotypes, namely, Methanobrevibacter oralis, Methanobacterium curvum/congolense, and Methanosarcina mazei. Archaea can be detected in healthy individuals, but its prevalence seems to increase in subjects with periodontitis.

•Oral fungal colonization:-

The oral cavity of newborns may be colonized by yeasts, specifically Candida, on their first day of life; and during the first year, the rate of oral colonization by Candida may vary between 40 and 82%. However, in older children the frequency of colonization decreases to values between 3 and 36%.These variations in the frequency of oral Candida colonization in children may be due to the physiological factors related to age, namely immune maturation, as well as other factors such as environmental changes (hospital vs. home) and diet alterations (breastfeeding vs. formula feeding).After infancy, the prevalence of oral Candida colonization gradually increases until old age, reaching up to 75% in healthy subjects.Although C. albicans is the most frequently detected fungi in the oral cavity of healthy children, the species C. parapsilosis has also gained some importance.

•Oral protozoan colonization:-

the protozoa are more frequent colonize the oral cavity. Entamoeba gingivalis and Trichomonas tenax are the most frequent and are normally non-pathogenic commensal microorganisms. Although their oral colonization is associated with poor oral hygiene and a low socioeconomic status, these protozoa can also be found in caries-free children and adolescents. The protozoa's rate of colonization increases with age, being more frequent in children aged between 11 and 19 years than in younger children. However, protozoa are much more prevalent in adults, particularly in those with periodontal disease. It is interesting to note that both protozoa can occur simultaneously, but the rate of colonization of E. gingivalis appears to increase more rapidly with age in relation to that of T. tenax.

the above information will definately helps you to clear your vision .