normal microflora

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.