Normal Flora😇🙏 Flashcards
2 Types of Normal Microbiota
Resident microbiota
Transient microbiota
NOTE: Suppression of the normal microbiota clearly creates a partial void that tends to be filled by organisms from the environment or from other parts of the body
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Number and variety of microorganisms present on the skin depend on many factors
- Anatomical position
- Amount of moisture present
*pH - Temperature
- Salinity
- Presence of chemical wastes such as urea
and fatty acids - Presence of other microbes, which may be
producing toxic substances
Skin pH
slightly acidic pH (4.0-6.0). due to organic acids produced by staphylococci and secretions from skin sebaceous and sweat glands. The acidic pH discourages colonization of many bacteria.
Sweat of some parts of the skin contain a high concentration of salt. This makes the skin surface__________(hyperosmotic or hyposomotic) which stresses most microorganisms.
hyperosmotic (cell shrinks)
________ from sweat glands on the skin are bacterial inhibitory substances. They help control of colonization, overgrowth and infection from resident microorganisms.
Lysozyme
The number of superficial microorganisms may be diminished by daily scrubbing with soap containing_________ or other disinfectants, but the microbiota is rapidly replenished again.
hexachlorophene
Is the upper respiratory tract sterile or not?
(nasal passages and the throat (pharynx)
Non-sterile
Is the lower respiratory tract sterile or not?
(larynx (voice box), trachea, bronchi, bronchioles, and lungs.)
Sterile
DUE TO:
1. The continuous stream of mucus generated by ciliated epithelial cells
2. Phagocytic action of alveolar macrophage
3. Lysozyme in mucus that has bactericidal effect
harbors pathogenic microorganisms but do not have the disease associated with them (diphtheria, meningitis, pneumonia, and whooping cough)
These carriers are unaffected but can transmit them to susceptible persons.
Healthy carriers
Middle ear and inner ear – sterile or not
sterile
Outer ear and auditory canal – (sterile or not)
Non-sterile. same microbes on skin
Cough, sneeze, blows the nose – these microbes may be carried along the ______ into the middle ear where they can cause infection
eustachian tube
The anatomy of the ______ affords shelter for numerous anaerobic and aerobic bacteria
oral cavity
Those that cannot attach are removed by the mechanical flushing from the oral cavity to the stomach where they are destroyed by _________
hydrochloric acid (HCl)
When teeth erupt
Rothia spp.
dental plaque, cavity
Streptococcus mutans
Gastric enzymes with pH ________of stomach
- prevent growth of indigenous microbiota, and most transient microbes
pH (1.5)
prevent growth of indigenous microbiota, and most transient microbes in the stomach
Gastric enzymes
lives in some people’s stomachs and is a common cause of ulcer
Gram-negative bacillus Helicobacter pylori
leads to a great increase in microbial flora of the stomach, including many organisms usually prevalent in feces
- Administration of antacids
- H2-receptor antagonist
- Proton pump inhibitors for peptic ulcer disease * Gastroesophageal reflux disease
part of GIT – few microbes will grow because the bile inhibits their growth
Duodenum
- Many grow in lower intestine (jejunum and ileum)
resident bacteria displace and inhibit potential pathogens indirectly by
bacteriocins and lactic acid.
Metabolic functions
* contribute to the ______requirement of the host if they are not provided in diet
amino acid
bacterias in the GIT synthesize
vitamin K, biotin, and folate
- enhance ion absorption
assist fermentation of nondigestible dietary residue - influence fat deposition in the host leading to obesity
Persistent recurring UTIs often develop when there is __________of the urethra, which allows the invasive organisms to multiply
obstruction or narrowing
frequent cause of urethral infection and are easily introduced into urethra by sexual intercourse
Chlamydia trachomatis, Neisseria gonorrheae Mycoplasmas
pH * During puberty and after menopause
alkaline secretions supporting growth of various microbes
pH Childbearing years
– acidic secretions (pH 4.0-5.0), encouraging growth mainly of lactobacilli
