Lecture 5 Flashcards

Question

Normal eye flora

Answer 1

From birth throughout life, there are small numbers of bacteria present on the conjunctiva Includes Staphylococcus and Streptococcus Numbers held in check by lysozyme in tears

Answer 2

Similar bacteria and yeast as found on skin Most common:Staphylococcus Also Streptococcus, Pseudomonas, Enterobacteriacae (Gram negative intestinal bacteria), Malasezzia (yeast)

Answer 3

Contains hundreds to thousands of different species of microbes Divided into 2 populations: Aerobic – associated with teeth Facultative anaerobes, anaerobes – periodontium Bacterial plaque = mat of microbes (biofilm) solidly attached to teeth Increased colonization if enamel wear/scratches, malocclusion, diet high in fermentable carbohydrates, poor hygiene If plaque is extensive, will extend subgingivally where it changes from aerobic to anaerobic populations

Answer 4

Limited number of normal flora Most common are Lactobacillus, Enterococcus, Helicobacter felis

Answer 5

Distinct and complex normal flora Allows animal to digest and extract nutrients from cellulose (e.g. hay, grass) Microbes themselves are also digested by the animal to provide macronutrients Ability to derive nutrition from cellulose and normal flora enable ruminants to survive under very harsh nutritional/environmental conditions (deserts, arctic tundra, rocky mountains) 10^12 microbes/ml rumen fluid Composed of bacteria, protozoa, fungi, archaea and viruses Gram negative bacteria predominate Most common bacteria are E. coli, Lactobacilli, Streptococcus bovis, Bacteroides Fibrolytic microbes break down cellulose Mostly strict (some facultative) anaerobes Anaerobic bacteria ferment sugars to alcohols and acids that are absorbed through the rumen wall Lactobacilli produce building blocks for milk sugar production

Answer 6

Archaea are evolutionarily “old” prokaryotic organisms Make-up ~3% of microbial mass Convert hydrogen gas and CO2 (by-products of cellulose fermentation) to methane: H2+ CO2 → CH4 Methane is belched out during rumination

Answer 7

Bacteriophage are viruses that infect and kill bacteria Causes cells to lyse Contents are then used as nutrients by the animal

Answer 8

Bacteria, fungi, protozoa Very few microbes in the duodenum Microbe numbers increase moving distally towards cecum Mixed anaerobes Strict anaerobes > facultative anaerobes Enterococcus, E. coli, Enterobacteriacae, Clostridium, Lactobacillus Some pathogenic bacteria may be present in very small numbers in healthy animals ( Salmonella, Campylobacter– both associated with food poisoning)

Answer 9

Vitamin synthesis Vitamin K production Vitamin B9 (folate), B12 (cobalamin) Contribute to digestion, especially fiber Enhance segmental contractions, peristalsis Inhibit colonization by pathogenic bacteria Competition Production of bacteriocins Stimulate immune tissues in the small intestine Take part in drug metabolism pathways

Answer 10

Largest microbial population in body 10^11 bacteria / gram feces Mostly anerobic bacteria (strict and facultative) Dominant species is E. coli in cats, dogs, bovids Also fecal Streptococcus ,Enterococcus ,Klebsiella, Bacteroides, Clostridium, Lactobacillus, Bifidobacterium, Enterobacteriaceae Also Candida (yeast), enterovirus, adenovirus Strains of E. coli that are pathogenic to humans found in 30% of dog feces sampled in one study Also present in cattle feces Colonization starts at birth with ingestion of birth canal secretions and feces Also acquired through nursing Profile of flora changes with diet Will also change with GI inflammation Rapidly affected by oral antibiotics Oral antibiotics will ALWAYS affect the normal GI flora If enough of the normal flora is eliminated, tend to see Clostridial overgrowth, which can lead to diarrhea and/or colitis Lack of balance between normal flora and the immune system can contribute to Irritable Bowel Disorder

Answer 11

Rod-shaped Gram negative Motile Non-spore-forming bacteria Can ferment lactose Normally found in feces Also can be found in water, soil, on vegetation when found in the environment, it is an indicator that there was fecal contamination

Answer 12

Escherichia, Enterobacter, Klebsiella

Answer 13

Small Intestinal Bacteria Overgrowth When the normal flora of the small intestine starts to resemble the colon Occurs when there is decreased peristalsis and/or damage to the cecum --> allows normal large intestinal flora to migrate into small intestine

Answer 14

Create gas → cause gas distension Interfere with digestion/absorption Compete for nutrients

Answer 15

Inflammation, diarrhea, colic

Answer 16

The liver is sterile (no normal flora) If there is biliary cholestasis (lack of proper bile acid flow through the bilary ducts), bacteria that was in the gallbladder could potentially enter the liver After death there is rapid contamination of the liver from intestinal bacteria

Answer 17

Contaminated Normal flora: Staphylococcus aureus, Mycoplasma spp.; also bacteria normally found on skin and fur Can habor chronic asymptomatic pathogens that are NOT considered normal flora

Answer 18

Mix of bacteria found on skin and vagina

Answer 19

Flora changes with cycling estrogen levels Lactobacillus, Streptococcus canis, Staphylococcus aureus

Answer 20

Distal urethra -Normal flora consistent with skin microbes -Colonization with normal flora from the intestinal tract tends to cause disease Proximal urethra and bladder in males -sterile Proximal urethra and bladder in females -Supposedly sterile, in reality is transiently colonized by flora from the distal urethra -numbers are very, very low

Answer 21

Colonization in the proximal urethra and bladder is with microbes from the skin, fur, external genitalia and feces Colonization is usually prevented by: Flushing during urination Distance from the outside Urine pH inhibits growth of microbes Normal urine pH is 6.2-6.5 Some bacteria can produce urease, which cleaves urea to increase the pH of the urine so it is more hospitable to colonization Epithelial cells produce antimicrobial substances that inhibit bacteria from attaching and replicating

Answer 22

Always sterile - any microbes present are always considered pathogenic Prostate secretes its own prostatic anti-bacterial factor Uterus is protected by the cervix Production of acid by Lactobacillus in the vaginal mucosa also prevents colonization by other bacteria Changes to the cervix and vagina during estrus increase risk that bacteria can enter uterus Many persistent pathogens can potentially colonize the genital tract (i.e., STDs) May be present in otherwise healthy animals but are never considered normal flora

Answer 23

Bacillus spp. and Staphylococcus hominis most important Prevent colonization of teats with pathogenic bacteria

Answer 24

Mammary glands at constant risk of infection, Milk is an ideal culture medium Trauma to the teat ends during milking allow bacteria to enter readily

Answer 25

Internal tissues Brain, spinal cord Bone, muscle, joints Heart, blood Inside of the eyeball Kidneys, liver, spleen Peritoneum, pleural space Lower respiratory tract Bronchi, bronchioles, lung parenchyma Upper urogenital tract (Proximal urethra and bladder), ureters, kidneys, uterus, prostate

Answer 26

AKA germ-free animals Used to describe an animal that is totally free of microorganisms NO infection NO normal flora Animal is born by cesarean under complete asepsis → transferred to sterile environment (sterile air, food, bedding, water) Used for research Very high risk of infection if exposed to the normal environment

Answer 27

Used for research These are axenic animals, to which known, specific microbes are introduced Result is an animal with known identities of all normal flora and other microbes Must be maintained in otherwise sterile environments to prevent introduction of unknown microbes

Answer 28

Specific Pathogen Free Used for research Animals that definitely do not have a specific microbe/pathogen If that microbe/pathogen is introduced to the animal, any change that occurs is specifically attributed to the introduction of the new microbe/pathogen