Unit 7C Flashcards
Describe salmonella
Gram negatice Rods Facultative anaerobes Motile (flagella) Non-lactose fermenting on MacConkeys Fastidious (strict growth requirements) (may need special transport media) Enteric, coliform Primary pathogen found in all animal species Many strains
Present in very low numbers in intestines and feces but not considered normal flora (asymptomatic carriers)
Animal resevoirs are maintained by spreading and contaminated feeds
What is salmonellosis and what are the 3 types if clinical disease
Diseases caused by salmonella enterica
Enteritis (secretory diarrhea)
Septicemia
Enteric fever
Pathology and clinical disease is similar in people and animals
describe transmission of salmonella
Resevoirs (asymptomatic carriers)
Shedding when stressed
Fecal oral transmission
Food borne transmission (feces, egg, milks, meat)
Direct from pet reptiles/turtles to people
Salmonellosis -enteritis
Most common clinicak presentation
Occurs 6-48 hours after minimum infectious dose
Nausea, fever, vomiting, cramps, secretory diarrhea
Bacteria infect celks and alter electrolyte absorption (minimal damage)
Lasts 2 days to 2 weeks (will resolve in healthy)
Maybcontijue to shed cor a long time after clinical stage resolves
Salmonella zoonosis
One of the major causes of food born illness in people
Signs: Diarrhea, vomitting, fever, upset stomach
What are the food borne sources of infection of salmonella
Contaminated poultry, eggs and dairy
Contaminated feces (especially in kids) from fecal oral transmission (especially from turtles and lizards)
Contamjnated water, rodents, wild fowl
What are mycobacterium
Genus that contains a number of bacteria that cause serious disease (tuberculosis and leprosy)
What do mycobacterium look like
Bacteria cell structure: very small rods, colonies form hyphae (fungi look like long thin threads)
Distinct cell wall (contain a lipid lyer and a wax layer (mycolic acids)
What is acid fast stain
Mycobacterium need to be stained with acid fast technique to be able to penetrate wax layer because they do not stain with gram stain
What does the wax layer of mycobacterium help with
Resistance: wax layer is protective, has lots of antibiotic drug resistnace, and resistant to pH changes, detergents and drying
How is mycobacterium immunogenic
Great at activating inflammation
Purified cell wall is a component added to many vaccines to engance immune activity (called an adjuvant)
Characteristics of mycobacterium
Aerobic Non- spore forming Non motile Catalase positive Very long generation time (fast growing species have visible colonies in 7 days, some take 2 years, compared to E. coli who takes minutes)
Bovine tuberculosis
AKA: M. Bovis (mycobacterium)
Slow progressive lung disease which is eventually fatal
10% of infected aniamls develop clincal disease
90% are latent infections (hard to identify and can spread)
Resevoir in the wild (deer and elk)
Zoomotic
Common route of transmission: respiratory
Diagnosis of bovine tuberculosis
Post mortem necrops (presence of tubercles and a culture)
Tuberculin testing
describe tuberculin testing (CFIA certofied test)
Tuberculin (cell wall extract from bacteria is injected into the skin
Animals that have been infected for at least a month will reaponde to tuberculin and create an infmmatory lesion at injection site
Identifies silent carriers and clinically affected animals
Bovine tuberculosis is a reportable disease, there is madatory testing in high risk areas and if the animal is found at slaughter, the whole herd will be tested by CFIA) how do you control the spread of it
Quarantine
Investigation
Euthanasia of all infected and exposed animals
Cleaning and disinfection
No restocking for that herd for 45 days (producers are compensated per head)
What is mycoplasma
Smallest prokaryote (0.3-0.8 microns)
Structurally simple: no cell wall and pleiomorphic
Simple genome: 470-700 genes (limited genes= limited enzymes = limited functions that the cell is able to carry out on its own)
Complex nutritional requirements: lost fo essential amino acids and cofactors, requires external sources of sterols
Can hijack the host cell’s enzyme pathways
Disease caused by mycoplasma are difficult to treat ___
Because its is variable where and what they infect and they have no cell wall and few enzymes to target with drugs
What is mycoplasma anemia
AKA: mycoplasma haemofelis
Used to be called: hemobartonella felis
Disease infects RBCs (surface attachment), looks like small blue/pruole sots in the surface of RBCs
Can be seen with Diff-quick stains
Usually cocci, cab be ribg shaped or coccobacilli
Less often in cytoplasm
What does mycoplasma anemia cause
Anemia: immune system sttacks RBCs that have mycoplasma
Initial diagnosis is usually on erythrocyte morphology
Species specific but disease is similar in cows, dogs, people and mice
Can soread via arthropd vectors (ticks, lice, mosquitoes)
What is an endotoxin
membrane compounds of Gram-negative bacteria which elicit an inflammatory response in host
What is an exotoxin
secreted proteins which act locally and at distance of bacterial colonization site
What is an enterotoxin
toxin produced in or affecting the intestines
What is a coliform
rod-shaped Gram-negative nonspore forming and motile or nonmotile bacteria that can ferment lactose with the production of acid and gas when incubated at 35–37°C. They are a commonly used indicator of sanitary quality of foods and water.
