Microbiology of the Mouth and Respiratory Tract

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Questions and Answers

What is the role of normal flora in the intestines in regards to digestion?

Eliminating non-resident flora from the skin

Producing mucin to prevent pathogenic organisms from attaching

Aiding in the metabolism of steroids

Producing enzymes such as cellulose, galactosidase, and glucosidase (correct)

What is the source of normal flora in the newborn?

The environment

The mother's genital tract during delivery

The skin and respiratory tract of individuals who handled the newborn

All of the above (correct)

What is a function of intestinal flora in regards to metabolism?

Eliminating non-resident flora from the skin

Breaking down complex carbohydrates

Producing mucin to prevent pathogenic organisms

Aiding in the metabolism of steroids (correct)

Which bodily fluids are considered sterile?

Blood, CSF, and synovial fluid Signup and view all the answers

What is the function of lysozyme in the skin?

Eliminating non-resident flora from the skin Signup and view all the answers

Which of the following is NOT a site where normal flora is typically found?

Urinary bladder Signup and view all the answers

What is the most common cause of duodenal ulcer?

Helicobacter pylori Signup and view all the answers

What percentage of the colon's flora is composed of anaerobes?

95%-99% Signup and view all the answers

What is the primary reason for the scanty flora in the small intestine?

Constant peristaltic movement of the intestine Signup and view all the answers

What is the predominant intestinal flora in breast-fed infants?

Bifidobacterium/Lactobacillus bifidum Signup and view all the answers

What is the percentage of facultative aerobes in the colon's flora?

1%-4% Signup and view all the answers

What is one of the roles of intestinal flora in the body?

Synthesis of vitamin B complex and vitamin K Signup and view all the answers

What type of bacteria is commonly found in the small intestine?

Streptococci and Lactobacilli Signup and view all the answers

In bottle-fed infants, what is the predominant intestinal flora?

Lactobacillus acidophilus Signup and view all the answers

What is one way normal flora of the digestive tract prevent colonization of the intestines?

By competing with transient flora for nutrients Signup and view all the answers

Which of the following bacteria are found in the female urethra?

All of the above Signup and view all the answers

What is the predominant vaginal flora in female infants?

Lactobacillus spp. Signup and view all the answers

What is the role of Lactobacillus in preventing gonococcal infection?

Producing lactoc acid Signup and view all the answers

What is the characteristic of the vaginal flora in young girls?

More prone to development of gonococcal infection Signup and view all the answers

What is the normal flora of the digestive tract responsible for?

All of the above Signup and view all the answers

What is the characteristic of the vaginal flora after menopause?

Similar to those found during pre-puberty Signup and view all the answers

What is the consequence of overgrowth of fungi such as Torulopsis and Candida in the vagina?

Vaginal infections such as vaginitis Signup and view all the answers

Study Notes

Mouth and Respiratory Tract

Viridans streptococci are implicated in the parthenogenesis of dental carries
Gingival crevices and tonsillar crypts are primarily inhabited by anaerobic flora (e.g., Bacteroides and Spirochetes)
Normal flora of the pharynx and trachea are similar to those found in the oral cavity
Transient carriage of potentially pathogenic organisms can occur in the pharynx, including Haemophilus influenza, Streptococcus pneumonia, Neisseria meningitides, and Mycoplasma
Initial colonization by pathogenic organisms may occur in the upper respiratory tract, including Neisseria meningitides, Corynebacterium diphtheria, and Bordetella pertussis

Conjunctiva

Normal flora in the conjunctiva are very scanty due to the flow of tears containing lysozyme
Transient colonization of the conjunctiva can occur by Neisseria, Moraxella, and Corynebacterium
Staphylococci and Streptococci may also be present

Digestive Tract

Helicobacter pylori is the most common cause of duodenal ulcers
The small intestine has scanty flora due to constant peristaltic movement
Most bacteria cultured in the small intestine are transient, including Streptococci, Lactobacilli, and Bacteroides
The colon is inhabited predominantly by anaerobes (95%-99%), including Bacteroides flagilis, Bifidobacterium/Lactobacillus bifidum, Eubacterium, Peptostreptococcus, and Clostridium
In bottle-fed infants, the predominant intestinal flora is Lactobacillus acidophilus
1%-4% of the flora of the colon are facultative aerobes, predominantly Escherichia coli and Enterobacteriaceae

Functions of Intestinal Flora

Synthesis of Vitamin B complex and vitamin K
Conversion of bile into bile acids
Competition with transient flora for nutrients
Prevention of colonization of the intestines by transient flora
Production of potentially pathogenic by-products of metabolism that are toxic to transient flora

Genitourinary Tract

The urinary system is considered sterile at about 1 cm of the urethra
In the anterior urethra, flora include S. epidermidis, enterococci, and diptheroids
Mycobacterium smegmatis may be found as normal commensals in male and female secretions
Gardnerella vaginalis, Bacteroides, and alpha streptococci may be found in the penile urethra
The female urethra is sterile or contains Staphylococcus epidermidis
Vaginal flora varies depending on age, hormonal levels, and vaginal pH
Lactobacillus spp. are the predominant flora in female infants
From 1 month to puberty, microorganisms that may inhabit the vagina include Staphylococcus epidermidis, Streptococci, diphtheroids, and Escherichia coli
Onset of puberty, predominant flora include Lactobacillus acidophilus, Corynebacterial, Peptostreptococci, Streptococci, Bacteroides, and Staphylococci
Lactobacillus plays a crucial role in preventing gonococcal infection by producing lactic acid
Fungi such as Torulopsis and Candida may also be found (10-30%)
Conditions that allow the overgrowth of these fungi can lead to vaginal infections such as vaginitis

Resident and Transient Flora

Resident flora: relatively fixed types of organisms that are regularly found in a given area of the body at a given age, contributing to overall health
Transient flora: temporarily inhabiting the skin and mucous membrane for hours, days, or weeks, derived from the environment

Other Beneficial Effects of Normal Flora

Preventing pathogenic organisms from attaching to and penetrating the skin and other tissues by producing mucin
Aiding in the digestion of food by producing enzymes such as cellulose, galactosidase, and glucosidase in the intestines
Helping in the metabolism of steroids

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Description

This quiz covers the normal flora of the mouth and respiratory tract, including bacteria like streptococci and anaerobic organisms, as well as potentially pathogenic microorganisms.