Module normal flora of human body microbiology 80 notes mechanisms. Rumen bacteria account for 10 10 organismml of rumen fluid and several hundred species have been characterized to date. The normal flora may antagonize other bacteria through the production of substances which inhibit or kill nonindigenous species. On the skin and mucous membranes, the resident flora may prevent colonization by pathogens and possible disease through bacterial. Normal flora normal microbiota in human the term normal flora denotes the mixture of microorganisms bacteria and fungi that inhabit many sites usually skin and mucous membranes of healthy human body, but bacteria are the most numerous. These are mixture of microorganisms regularly found at any anatomical siteon within the body of a healthy person. Guide to the normal bacterial flora of humans clostridia members of the genus clostridium found in the the intestinal tract clostridium difficile. In that respect are larger numbers of bacteria than cells present in ones body. On the other hand, members of the normal flora may themselves produce disease. Bacterial synergism between a member of the normal flora and a potential pathogen. The main factor determining the composition of the normal flora in a body region is the nature of the local environment, which is determined by ph, temperature, redox. Bacterial flora in a normal person in a hospital or longterm care facility, bacterial flora in a normal person in the community, how antibiotic prescribing influences normal flora and the ward environment, circumstances affecting normal flora, what is no. The bacteria which may be recovered from the normal human eye have been recorded in the literature a number of times.
A diverse microbial flora is associated with the skin and mucous membranes of every human being from shortly after birth until death. Multiple factors regulate the population number of these bacteria, including gastric acidity, intestinal transit, dietary factors, antibiotic use, and bacterial interactions with other bacteria and with the epithelium. One gains the impression that generalization is very difficult and that perhaps such diversity is a characteristic of the bacterial flora of the normal human skin. In normal hosts the duodenal flora is sparse 0 to 10 3 g of contents. Bacterial classification, structure and function introduction the purpose of this lecture is to introduce you to terminology used in microbiology. Helicobacter pylori is a potential stomach pathogen that apparently plays a role in the formation of certain ulcer types. Normal bacterial flora of vagina pages with reference to book, from 1 to 3 nasreen kirmani pmrc research centre, jinnah postgraduate medical centre, karachi. To describe the conjunctival flora of normal human eye which vary with. The intestinal bacteria produce a variety of substances ranging from relatively nonspecific fatty acids and peroxides to highly specific bacteriocins, which inhibit or kill other bacteria. Gram stain of a species of micrococcus, commonly isolated from the skin and nasal membranes of humans. Normal flora and their various location in the body. They consists of both non pathogenic and potentially pathogenic bacteria which inhabit the body surface or mucous membranes for a limited period of time.
Figure 61numbers of bacteria that colonize different parts of the. Studies of the normal bacterial flora of the female genital tract are primarily limited to characterization of the types of bacteria present in women who do not have identifiable disease. In microbiology, collective bacteria and other microorganisms in a host are known as flora. The normal flora of humans consists of a few eucaryotic fungi and protists, but bacteria are the most numerous and obvious microbial components of the normal flora. Bacterial flora plays an important role in host health in a variety of tissues and organ systems such as the skin, gastrointestinal tract, and urogenital system, as well as the respiratory system. An average adult human is covered with approximately 2 m2 of skin. This bacterial population constitutes the normal microbial flora.
It is important to fully define the human microflora of the healthy oral cavity before we can understand the role of bacteria in oral. They can be removed from the body surface by mechanical means such as meningococcus and pneumococcus can be removed from the human nasopharynx from time to time. Normal flora are microorganisms bacteria, fungi, protozoa, and viruses, mostly bacteria that continuously inhabited the human body resident normal flora. Normal flora definition normal flora is the mixture of microorganisms bacteria and fungi that are regularly found at any anatomical site of human body 3. The normal bacterial flora of the human intestine and its re. The normal flora is a bacteria found in or on ones bodies on a temporary basis without causing disease. Human skin has relatively fewer number and types of normal flora.
In this article we will discuss about the normal microflora of different parts of human body. Although this organism has long been isolated from expectorated sputum from patients with pneumonia, h. Introduction the normal flora can be divided into two groups resident flora and transient. The anaerobic condition of colon is maintained by aerobic bacteria which utilizes the free oxygen. Skin microflora and bacterial infections of the skin. The oral cavity of infant is free from bacteria but rapidly normal flora will be colonized such as streptococcus salivarius. Pathogenesis of bacterial infection and flora normal. Many of these components discourages the growth of microorganism in skin. Module normal flora of human body microbiology 78 notes 7 normal flora of human body 7. Role of normal flora immunostimulation a they produce antibodies which may contribute to host defenses. As these microorganisms colonise the dental surface and gingiva, colonization of streptococcus sanguinis and streptococcus mutans are formed on the teeth. Under normal conditions, normal flora does not cause disease, but if. This because the face and hands are likely inoculated with the bacteria on the nasal membranes. Normal flora definition of normal flora by medical dictionary.
The human microbiome is the aggregate of all microbiota that reside on or within human tissues and biofluids along with the corresponding anatomical sites in which they reside, including the skin, mammary glands, placenta, seminal fluid, uterus, ovarian follicles, lung, saliva, oral mucosa, conjunctiva, biliary tract, and gastrointestinal tract. We are covered with, and contain within our intestines. The importance of a normal balance in the numbers and types of bacteria and fungi present on the skin surface, i. The normal microbial flora is relatively stable, with specific genera populating various body. Normal bacterial flora can be arranged into two groups. Aug 28, 20 the normal flora in humans usually develops in an orderly sequence, or succession, after birth, leading to the stable populations of bacteria that make up the normal adult flora. Recently, the more appropriate term microbiota is applied, though its use has not eclipsed the entrenched use and recognition of flora with regard to bacteria and other microorganisms. The type and density of bacteria are determined by anatomic location, local humidity, the amount of sebum and sweat production, and the hosts hormonal status and age aly et al, 1991. Microorganisms including bacteria, protozoa, and fungi that are found on or in specific areas of the body. The normal microbial flora is relatively stable, with specific genera populating. This means that one organism is helping another to grow or survive. The human body, which contains about 10 cells, routinely harbors about 1014 bacteria fig. Members of the resident flora in the intestinal tract synthesize vitamin k and help absorb nutrients. Only few normal flora are present in the upper part of small intestine because bile kills them.
Pathogenesis of bacterial infection and flora normal free download as powerpoint presentation. Microbiology of sinusitis proceedings of the american. Multiple factors regulate the population number of these bacteria, including gastric acidity, intestinal transit, dietary factors, antibiotic use, and bacterial interactions with other bacteria. Jun 15, 2010 the bacteria recovered from pediatric and adult patients with communityacquired acute purulent sinusitis are the common respiratory pathogens s. Normal flora is the term used to describe the various bacteria and fungi that are permanent residents of certain body sites, especially the skin, oropharynx, colon, and vagina tables 61 and 62.
There are examples of a member of the normal flora supplying a vitamin or some other growth factor that a pathogen needs in order to grow. Though widely known as flora or microflora, this is a misnomer in technical terms, since the word root flora pertains to plants, and biota refers to the total collection of organisms in a particular ecosystem. Normal flora and respiratory tract pathogens annals of. Theproductionofacidsasanendproductof carbohydratemetabolismiscommoninmanyspeciesof. The thought is that these interventions can correct an imbalance, or dysbiosis, of the gut flora. The bacteria on the surface are heat killed, as are the tissue cells of the surface, and initial swab cultures are usually sterile. Although microflora is commonly used, the term microbiota is becoming more common as microflora is a misnomer. Resident normal flora consists of relatively fixed types of bacteria regularly found in a given area at a given age. Microbiota with animallike characteristics are classed as microfauna. Some causes of otitis media are caused by bacteria found in the outer ear.
The bacterial flora is similar in lower ileum, caecum and rectum. A total of 200 conjunctival swabs from 100 patients with healthy eyes were sent for microbiological evaluation to describe the various microorganisms isolated as normal flora of conjunctiva. Understanding the bacterial flora of the female genital. These members of the normal flora form part of the host and. Viruses and parasites protozoa and helminths, which are the other major groups of microorganisms, are usually not considered members of the normal flora, although they can be present in. The range of these microorganisms however vary in different individuals due to variation in genetic makeup, nutrition, age, sex. Bacteria species are an important source of microbial protein, which supply the ruminant with 7580% of its metabolizable protein glossaryview all metabolizable protein. The ileum contains a moderately mixed flora 10 6 to 10 8 g of contents. The bacterium is found on skin, nasal membranes and the conjunctiva of the eye. Number of normal flora differs depending on location and types of skin. A sterile milieu prenatally, human skin soon becomes host to resident bacteria after birth. Skin consists of outer epidermis, inner dermis with hair, sweat and sebaceous gland. The skin and mucous membranes of the oral cavity, intestines, upper respiratory tract, and vagina have specific, permanent flora.
The gastrointestinal tract is host to a number of bacteria that. The resident flora of certain body regions plays a crucial role in maintaining health and normal function. Learn vocabulary, terms, and more with flashcards, games, and other study tools. In general, bacterial human relationships may be normal flora or opportunistic infection or pathogenic infection. By volume, they comprise up to 50% of the total microbial biomass. Under normal conditions in a healthy human they are harmless and may even be beneficial. Certain older hypotheses relating to changes in the bacterial flora of the skin surface would appear to require reexamination as to their validity. Normal flora is the term used to describe the various bacteria and fungi that are permanent residents of certain. It has been estimated that this surface area supports about 1012 bacteria. Cover different classification schemes for grouping bacteria, especially the use of the gram stain 2. A healthy foetus in utero is free from microorganisms. Microorganisms of the normal flora may aid the host by competing for microenvironments. Quantitative studies have frequently been reported by investigators whose. Suppression of the normal flora tends to be filled by organisms from the environment or from other parts of the body and such organisms behave as opportunists and may become pathogens.
Normal flora are the microorganisms that live on another living organism human or animal or inanimate object without causing disease. Bacteria of normal endogenous skin flora are resistant to heat injury in practically the same degrees as are the skin cells. Understanding the bacterial flora of the female genital tract. Canuto 1 reported an approximate value of 253 bacteria per square centimeter of skin in a group of 23 subjects. The consistent findings of micrococcus pyogenes var.
The normal bacterial flora of the human intestine and its regulation. Some of these microorganisms are found in association with humans animals only. Definition normal flora is the mixture of microorganisms bacteria and fungi that are regularly found at any anatomical site of human body they are found in areas like. Introduction a diverse microbial flora is associated with the skin and mucous membranes of every human being from shortly after birth until death. The article by musher and associates 1 provides further evidence of the pathogenicity of nontypeable haemophilus influenzae. The normal flora occupy available colonization sites which makes it more difficult for other microorganisms nonindigenous species to become established. Characteristic gramnegative bacteria grampositive bacteria wall structure they have a thin lipopolysaccharide exterior cell wall. Targeting gut flora to treat and prevent disease mdedge. There is a distinctive predominant bacterial flora of the healthy oral cavity that is highly diverse and site and subject specific. Species typically associated with periodontitis and caries were not detected. The skin is an intricate habitat for many bacteria. Defining the normal bacterial flora of the oral cavity. Normaloradescription 197 environment,whichmaybeinhibitoryforcertainpathogens. In fact, following bacterial attack, the dental pulp becomes necrotic and the bacteria of the normal flora undergo a change from main aerobes to anaerobes leading to an abscess formation at the.
Some organisms are almost always present in a normal oral cavity and constitute constant normal microbial flora. Normal flora definition of normal flora by medical. Guide to the normal bacterial flora of humans corynebacteria includes corynebacterium and probionibacterium species located primarily on skin and upper respiratory tract propionibacterim acnes colonies. The skin and mucous membranes of the oral cavity, intestines, upper respiratory tract, and. The normal bacterial flora of the human intestine and its. Colony counts of aerobic bacteria from moist areas such as the axilla or toe web spaces can reach 10 7 bacteria per cm 2, whereas dry areas such as the forearm.