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Microof the human body
Semester -6th
Paper – Medical-microbiologyTopic – Normal flora BY: KHAN SHAH RUKHRoll no : 4181457022Submitted to: Dr. Sweta YadavCollege / Department: MICROBIOLOGY, SSN College ;University of Delhi
Introduction of normal floraFactors influencing normal floraDistribution of the normal floraNormal flora – skinNormal flora- upper respiratory tractNormal flora-gastrointestinal tractNormal flora-urogenital tractSignificance of the normal floraHuman microbiome projectSummaryReferenceQuestions
CONTENT
Microbes are all over us
http://commons.wikimedia.org/wiki/File:Man_shadow_-_upper.png
Thousands of different species on the skin aloneSome thrive on dry patches of the elbow, others thrive in moist environment of armpit
There are millions of microbes per square inch on your body
It is estimated that there are more microbes in your intestine than there are human cells in your body!
Germ-free Animals Regular Counterparts
Lifespan Twice One
Cause of death
Intestinal Atonia Infection
Anatomic & Physiological Changes
1. Alimentary lamina propria under-developed
2. No Ab3. Intestinal epithelial cell
renewal rate down half
Germ-free Animals vs Counterparts
1. Local Environment (pH, temperature, redox potential, O2, H2O, and nutrient levels…).
2. Diet3. Age4. Health condition
(immune activity…)5. Antibiotics,…..etc
Factors Influencing Normal Flora
Microbes are normally found in and on the human bodyThe following sites are “hotspots” for microbial life
http://nihroadmap.nih.gov/hmp/ Let’s explore these regions
Some microbes are native, normally found in the bodySome microbes are introduced, suddenly arriving at a new residence in the body
Respiratory tract and head outer ear, eye, mouth, oropharynx, nasopharynx Sterile sites: sinuses, middle ear, brain, lower
respiratory tract (trachea, bronchiole, lung)Gastrointestinal tract esophagus, stomach, small intestine, large
intestineGenitourinary system anterior urethra, vagina Sterile sites: bladder, cervix, uterusSkin
Sites of human body that the normal flora microbes colonize
Normal flora - Skin
What’s Happeningon the Skin?
There are several skin environments: oily, dry, moist. Some microbes prefer one over another.
The skin has natural defenses including slightly acidic sweat and antimicrobial peptides.
Microbes hide in crevices to recolonize skin after washing with soap
Antibiotic washes and oral antibiotics disturb normal balance of microbes on the skin
There is a normal balance of microbes on the skin that protect introduced microbes from harming us. Damaged skin gives opportunities for microbes to invade the bloodstream and cause serious illness.
Skin
• Propionibacterium acnes bacteria colonizes healthy pores, but if pores become clogged, it grows out of control
• Staphylococcus epidermidis bacteria normally colonizes on the skin. But when P. acnes clogs pores, S. epidermidis also grows out of control in the infected pores
• Staphylococcus aureus bacteria can also infect clogged pores like Staph epidermidis. Even worse, many antibiotic resistant strains of Staph aureus make it difficult to treat the infection.
Normal Flora- Upper Respiratory Tract
Figure 27.11
SinusesNasopharynxPharynxOral cavityLarynx
Trachea
Bronchi
Lungs
Upperrespiratorytract
Lowerrespiratorytract
© 2012 Pearson Education, Inc.
Nose
The interior lining of the nose contains mucous secreting glands. A wide variety of microbes are normally found there. Here’s a few:
http://commons.wikimedia.org/wiki/File:Human-nose.jpghttp://en.wikipedia.org/wiki/File:Staphylococcus_epidermidis_01.png
• Staphylococcus epidermidis bacteria forms a biofilm that coats the mucosal lining
• Staphylococcus aureus bacteria is fine when kept under control by a protease found in S. epidermidis, but if left to grow out of control, S. aureus can become pathogenic and cause infection
http://en.wikipedia.org/wiki/File:MRSA7820.jpg
What’s Happeningin the Nose?
Nose
http://commons.wikimedia.org/wiki/File:Human-nose.jpg http://en.wikipedia.org/wiki/File:Aspergillus_fumigatus_Invasive_Disease_Mechanism_Diagram.jpg
• Aspergillus fungal spores are often inhaled through the nose. If the immune system fails to clear these, mold can grow in the lungs
http://en.wikipedia.org/wiki/File:Aspergillus.jpg
• Corneybacterium accolens bacteria is rarely a pathogen, but if it enters the bloodstream due to a torn blood vessel, it can cause serious infections
http://en.wikipedia.org/wiki/File:Corynebacterium_ulcerans_01.jpg
Normal flora Gastrointestinal tract
Figure 27.9
Major bacteria present OrganEsophagus
Stomach
Smallintestine
Largeintestine
pH 2Secretion of acid (HCl)Digestion of macromolecules
pH 4–5
Continued digestionAbsorption of monosaccharides,amino acids, fatty acids, water
pH 7Absorption of bile acids,vitamin B12
Duodenum
Jejunum
Ileum
Colon
Anus
Esophagus
LactobacilliEnterococci
PrevotellaStreptococcusVeillonella
HelicobacterProteobacteriaBacteroidetesActinobacteriaFusobacteria
BacteroidesBifidobacteriumClostridiumEnterobacteriaEnterococcusEscherichiaEubacteriumKlebsiellaLactobacillusMethanobrevibacter (Archaea)PeptococcusPeptostreptococcusProteusRuminococcusStaphylococcusStreptococcus
Major physiologicalprocesses
© 2012 Pearson Education, Inc.
What’s Happeningin the Gut?
http://commons.wikimedia.org/wiki/File:Intestine_and_stomach_-_transparent_-_cut.png
Major barriers for microbes entering the gut:• low pH• Saliva and Bile• Immune system• Finding a place to attach to intestinal wall• Surviving a widely varied diet
For those microbes that manage to colonize the gut:• gut flora perform regular tasks of digestion, vitamin production,
many others
Gut
http://commons.wikimedia.org/wiki/File:Intestine_and_stomach_-_transparent_-_cut.png
http://microbewiki.kenyon.edu/index.php/File:G_reaction1.jpg
Ruminococcus sp. bacteria can be found in significantly high numbers in the gut flora. They break down cellulose in the gut, helping with digestion.
Helicobacter pylori bacteria has a helical shape and colonizes the stomach and upper G.I. tract. It is known to be a major cause of stomach ulcers, although many with H. pylori do not get ulcers.
http://commons.wikimedia.org/wiki/File:Helicobacter_pylori_diagram.png
Normal Flora-Urogenital Tract
Alpha hemolytic streptococcianaerobes streptococci (peptostreptococci)ProvotellaClostridiumGardnerella vaginalisUriplasma urilyticum
NORMAL FLORA -VAGINAMOST COMMON BACTERIA LEAST COMMON BACTERIA
Lactobacillus spStreptococcus sp.
Alpha hemolytic Streptococci,Anaerobes Streptococci,(Peptostreptococci )Provotella sp.,Clostridia sp.,Gardnerella sp,.Uriplasma urealyticum,Sometimes Listeria sp. and Mobiloncus sp.
Urogenital
http://commons.wikimedia.org/wiki/File:Female_Genital_Organs.svg
Lactobacillus and vaginal epithelial cell
http://commons.wikimedia.org/wiki/File:Lactobacillus_sp_01.png
Lactobacillus normally maintain low pH while other species are kept in small numbers in the vagina
If Lactobacillus decreases from antibiotics…
Candida albicans can take over and cause a yeast infection
http://en.wikipedia.org/wiki/File:Candida_albicans_2.jpg
G. vaginalis and vaginal epithelial cell
Gardnerella vaginalis can grow too much and cause bacterial vaginosis.
Interplay Between Medicine and Microbes
Antibiotics
Kills infectious bacteria but also disrupts natural flora. Can result in yeast infections, digestive problems, etc.
http://commons.wikimedia.org/wiki/File:NOVAMOXIN_antibiotic.jpg
http://commons.wikimedia.org/wiki/File:Chemotherapy_bottles_NCI.jpg
Chemotherapy drugs
Gut flora has been shown to modify some drugs during metabolism. This causes many side effects, including upset stomach.
Normal flora may act as opportunistic pathogens
Especially in hosts rendered susceptible by:
1. Immuno-suppression (AIDS & SCID)2. Radiation therapy & Chemotherapy3. Perforated mucous membranes4. Rheumatic heart disease…etc.
From friends and foe
Possible questions that may be answered by the HMPHow stable and resilient is an individual’s
microbiota throughout one day and during his/her lifespan?
How similar are microbiomes between members of a family, community or across communities in different environments?
Do all humans have an identifiable “core” microbiome and how is it acquired and transmitted?
What affects the genetic diversity of the microbiome and how does this diversity affect adaptation by the microrganism and the host to markedly different lifestyles and to various physiological or pathophysiological states?
GoalsNew diagnostic biomarkers of healthIndustrial application Deeper understanding of nutritional
requirements of humansPersonalized drug and diet regimen
Future ResearchBetter coverage needed for shotgun
sequencing.Also new experimental approach should be
created which allow the sequencing of the more fragile phyla of bacteria, such as bacteroitides.
Analyses of horizontal gene transfers in gut microbes.
Quantitation of metabolites etc, contributed and consumed by gut flora.
Effects of antibiotic administration of gut flora and the host, succesion of microbes after antibiotics, and creation of pathogenic specific antibiotics that don’t effeect the gut flora or at least minimalize effects.
SUMMARY
• Should a doctor consider a patient a single human organism or a community of organisms?
• What is the community of the human host and its microbes called?
• Where on a healthy human is the microbiome located?
• Does your body contain more of your own human cells or more microbial cells?
Comment on the normal flora of the gut and its significance?(2015)
Name any two bacteria inhabiting the skin?(2014)
Questions?
Reference Jawetz, Melnick, & Adelberg’s,Medical
Microbiology, Twenty-Sixth Edition Google search-slide share.com wikipedia.com andhttps://www.google.co.in/?gfe_rd=cr&ei=0avdVa3RI6TG8Aeb3pfQDg&gws_rd=ssl#q=human+microbiome+project+ppt
,https://www.google.co.in/?gfe_rd=cr&ei=0avdVa3RI6TG8Aeb3pfQDg&gws_rd=ssl#q=resident+microflora+in+human+ppthttps://www.google.co.in/search?sclient=psy-ab&site=&source=hp&q=normal+flora&oq=normal+flora&gs_l=hp.3...4311.8231.0.9194.13.11.0.0.0.0.0.0..0.0....0...
1c.1.64.psy-ab..13.0.0.0.rM6dRZ_quqc&pbx=1 .
http://commons.wikimedia.org/wiki/File:Lactobacillus_sp_01.png
In the womb, humans are free of microbes. Colonization begins during the journey down the birth canal, which is riddled with bacteria, some of which make their way onto the newborn's skin.