Normal Flora - PowerPoint PPT Presentation

Loading...

PPT – Normal Flora PowerPoint presentation | free to download - id: 3d8efc-YjMzY



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Normal Flora

Description:

Normal Flora What s growing on us? Normal Flora (mostly bacteria) In past Medical Microbiology focus on pathogenic MOs Realize MOs that normally colonize humans ... – PowerPoint PPT presentation

Number of Views:486
Avg rating:3.0/5.0
Slides: 42
Provided by: Instructio88
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Normal Flora


1
Normal Flora
  • Whats growing on us?

2
Normal Flora (mostly bacteria)
  • In past Medical Microbiology focus on pathogenic
    MOs
  • Realize MOs that normally colonize humans without
    harm can play role in disease
  • Many innocuous NF now known to be potentially
    pathogenic under certain circumstances (what
    circumstances?)
  • Therefore, important to acquire knowledge about
    our NF

3
Knowledge of Normal Flora
  • Understanding of NF found at specific body
    location provides insight into possible
    infections that result from injury
  • Knowledge of NF at a body site gives clinician
    perspective on possible source and/or
    significance of MOs isolated from site of
    infection

4
Origin of Normal Flora
  • Healthy fetus, in utero, is essentially free of
    MOs
  • Infant exposed immediately to MOs when passing
    through moms vaginal tract and then to MOs in
    environment
  • Within few hours, oral and nasopharyngeal flora
    of neonate established
  • Within one day, resident flora of lower
    intestinal tract established

5
Adult Normal Flora
  • MOs that normally live on or in any part of the
    body without causing disease
  • Two basic types of NF
  • Resident NF normally GROW on/in indicated body
    site, presence fixed in well defined distribution
    patterns
  • Transient NF only TEMPORARILY PRESENT on/in
    indicated body site, usually dont become firmly
    entrenched but simply die within hours

6
Skin Normal Flora
  • Staphylococcus epidermidis
  • Staphylococcus aureus
  • Propionibacterium acnes
  • Corynebacterium
  • Streptococcus species
  • Candida albicans
  • Clostridium perfringens

7
Skin Normal Flora
  • Most skin NF found on superficial squamous
    epithelium, colonizing dead cells or closely
    associated with sebaceous and sweat glands
  • Secretions from these glands provide
    environmental conditions and nutrients for growth
    of numerous skin NF

8
Skin Hostile Environment
  • Subject to periodic drying
  • Certain parts (folds, areas near orifices)
    sufficient moisture support resident MOs
  • Slightly acidic pH due to organic acids (
    sebaceous sweat glands, Staphylococcus)
    prevents colonization of many MOs
  • Sweat contains high NaCl, producing hypertonic
    condition on skin surface that osmotically
    stresses many MOs

9
Skin Inhibitory Substances
  • Help control colonization, overgrowth, production
    of disease by resident MOs
  • Remember - colonization not necessarily mean
    infection and disease
  • Lysozyme produced by sweat glands and lyse G()
    MOs
  • Complex lipids metabolized by Propionobacterium
    acnes to unsaturated fatty acids that have
    antimicrobial activity (produce strong odor)
  • Use of deodorants with antibacterial substances,
    inhibit growth of G(), may lead to growth of
    G(-) MOs and infection

10
Skin Normal Flora
  • Staphylococcus epidermidis
  • Staphylococcus aureus
  • C, clusters

11
Skin Normal flora
  • Propionibacterium acnes
  • B, anaerobic
  • Diphteroids (club shaped)
  • Branching bacilli

12
Propionibacterium acnes
  • Harmless, but associated with acne during
    adolescence and overproduction of sebum by
    sebaceous gland
  • Provides ideal environment for growth of P. acnes
    and substances produced trigger inflammatory
    response leading to acne
  • Tetracycline (antibiotic) or accutane (prevents
    sebum secretions, some severe side effects) may
    be used for acne treatment

13
Skin Normal Flora
  • Corynebacterium
  • B, aerobic
  • Diphtheroids

14
Skin Normal Flora
  • Streptococcus species
  • C, pairs, chains

15
Skin Normal Flora
  • Candida albicans
  • Yeast, budding
  • Soil air

16
Skin Normal Flora
  • Clostridium perfringens
  • B, anaerobic spore former
  • Soil air

17
Nose Nasopharynx (NP) Normal Flora
  • Nasopharynx (part of pharynx above soft palate)
  • Staphylococcus aureus
  • Staphylococcus epidermidis
  • Diphtheroids
  • Streptococcus pneumoniae
  • Haemophilus influenzae
  • Neisseria meningitidis
  • may be causing disease if in large numbers
    (relative numbers important)

18
Nose NP Normal Flora
  • Haemophilus influenzae
  • B-, short cocobacilli
  • Fastidious

19
Nose NP Normal Flora
  • Neisseria meningitidis
  • C-, in pairs
  • coffee bean

20
Oral Oropharynx (OP) Normal Flora
  • Resist mechanical removal by adhering to various
    surfaces such as gums and teeth
  • MOs that cant resist mechanical flushing of oral
    cavity, swallowed, destroyed by HCl in stomach
  • Comfortable environment for MOs due to
    availability of water and nutrients

21
Oral OP Normal Flora
  • Viridans group a hemolytic Streptococcus sp.
  • Streptococcus pyogenes
  • Diphtheroids
  • Staphylococcus epidermidis
  • Staphylococcus aureus
  • Neisseria meningitidis
  • Other Neisseria species
  • Haemophilus influenzae
  • Other Haemophilus sp.

22
Oral OP Normal Flora
  • Candida albicans
  • Actinomycetes sp.
  • Lactobacillus sp.
  • Bacteroides sp.
  • Fusobacterium sp.
  • Enterobacteriaceae
  • probably causing infection if predominant
    organism found or in large numbers

23
Oral OP Normal Flora
  • Some Streptococcus species (sanguis, mutans,
    salivarious) adhere to teeth and contribute to
    formation of dental plaques and caries

24
Oral OP Normal Flora
  • Actinomyces
  • B, branching
  • Forms granules

25
Oral OP Normal Flora
  • Lactobacillus
  • B, anaerobe

26
Oral OP Normal Flora
  • Bacteroides sp.
  • B-, anaerobe

27
Oral OP Normal Flora
  • Fusobacterium sp.
  • B-, anaerobe

28
Oral OP Normal Flora
  • Fusobacterium nucleatum
  • B-, anaerobe
  • Enlongated

29
Oral OP Normal Flora
  • Escherichia coli
  • Family Enterobacteriaceae
  • B-, short, coccobacilli

30
Gastrointestinal (GI) Tract Normal Flora Stomach
  • Because of high acidic content very few MOs
  • Candida sp.
  • Lactobacilli
  • A few Streptococcus sp. (mainly Enterococcus
    faecalis)

31
GI Tract Normal Flora Small Intestine
  • Few MOs because inhibitory effects of stomach
    acid, bile, and pancreatic secretions
  • Enterococcus faecalis
  • Lactobacilli
  • Diphtheroids
  • Candida sp.

32
GI Tract Normal Flora Large Intestine
  • Largest microbial population in human body
  • 1012 MOs/gram feces
  • Over 300 different species of bacteria
  • The anaerobic/facultatively anaerobic bacteria
    ratio is 300/1

33
GI Tract Normal Flora Large Intestine
  • Bacteroides sp.
  • Fusobacterium sp.
  • Lactobacillus
  • Clostridium sp.
  • Peptostreptococcus sp.
  • Staphylococcus sp.
  • Enterococcus faecalis
  • Other Streptococcus sp.
  • Pseudomonas species
  • Enterobacteriaceae
  • Candida sp.

34
GI Tract Normal Flora
  • Pseudomonas species
  • B-, soil water

35
GI Tract Normal Flora
  • Peptostreptococcus species
  • C, anaerobe

36
GI Tract Normal flora
  • Normal physiological processes move MOs through
    colon, adult excretes 3x1013 daily
  • Under normal conditions resident NF self-limiting
  • Competition of MOs ( i.e. colicin by E. coli)
  • Mutualism with host (i.e. E. coli produces
    vitamin K and B for host)
  • Maintains status quo

37
GI Tract Normal flora
  • Anything disturbs intestinal environment (stress,
    altitude change, starvation, diarrhea,
    antibiotics) can alter NF leading to GI disease
  • Yeast infections
  • Antibiotic associated pseudomembraneous colitis)

38
Genitourinary (GU) Tract Normal Flora Urethra
  • Staphylococcus epidermidis
  • Enterococcus faecalis
  • Diphtheriods
  • Neisseria sp. (NOT N. gonorrhoeae)
  • Enterobacteriaceae

39
GU Tract Normal Flora Vaginal
  • Changes over lifetime ( i.e. menstrual cycle)
  • Lactobacillus (probiotic friendly bacteria)
  • Bacteroides
  • Enterococcus sp.
  • Staphylococcus epidermidis
  • Diphtheroids
  • Streptococcus agalactiae
  • Clostridium perfringens
  • Peptostreptococcus
  • Enterobacteriaceae
  • Candida albicans

40
GU Tract Normal Flora External Genitalia
  • Streptococcus sp.
  • Staphylococcus sp.
  • Diphtheroids
  • Bacteroides
  • Candida sp.

41
Class Assignment
  • Textbook Reading Chapter 2 Host-Pathogen
    Interaction
  • A. The Role of the Usual Microbial Flora
  • Key Terms
  • Learning Assessment Questions
About PowerShow.com