POD Unit 5: Bacteriology

Bacteria - characteristics

- UNICELL, MICROSCOPIC PROKARYOTES (0.5-5ug)

- Most are HARMLESS/HELPFUL

- Contain BOTH DNA and RNA,

- Cell wall RIGID, Peptidoglycan or cellulose?

- Replicate via BINARY FISSION

What is Microbiota? How is it affected?

- Collective of bacteria that inhabits body of animal

- Beneficial bacteria can keep host HEALTHY: Absorb nutrients, break down food, preventing growth of harmful bacteria

- Changes w body location, age, host, etc...

- Associated w physio and pathologies of animals

Explain the parts of the Bacterial Structure:

- Cell Envelope

- Flagella and Pili

- Spores

1. CELL ENVELOPE:

- Use for Dx

- Usually VIRULENT

- Some are PAMPs => target for antibiotics and disinfectants

2. FLAGELLA and PILI/FIMBRIAE

- Filament, protein

- Flagella => Motility

- Pili/Fimbriae: 2 types:

+ COMMON: Adhere to cell surface

+ SEX: Genetic exchanges

3. SPORES: Most dominant form

- Minimal metabolism and respiration

- Reduce enzyme production

How to do Bacterial Identifications? Based on what?

- Morphology

- Staining

- Culture

- Biochem rxn

- Molecular methods

- Immunological methods

3 Morphology of Bacteria?

1. Cocci (sphere)

2. Bacilli (rod)

3. Spirochetes (spiral/helix)

Difference between Gram (+) and Gram (-) bacteria

Differ in CELL WALLS/MEMBRANES:

(+):

- Has TEICHOIC acids => ANTIGENICITY

- Stain PURPLE (Positive for P)

(-):

- 2 layers

- High lipid

- Little peptidoglycan

- Stain RED

=> They have DIFFERENT ANTIBIOTIC RESPONSES!

Cultural methods: Media Forms and Media Types?

FORMS:

- Solid

- Semi solid

- Fluid

TYPES:

- Basic/all purpose

- Enriched

- Enrichment

- Selective (differential or transport)

How long do bacteria take to grow under optimal condition?

Divide every 20 minutes

=> Can use this to draw a bacterial growth curve

What Biochemical Rxn can be used to identify bacteria? (2)

1. CATALASE test:

- Differentiate those that produce catalase to break down H2O2 to O and H2O

- To differentiate STAPH. from STREP (staph is (+))

2. COAGULASE test:

- Identify those that produce coagulase, which converts fibrinogen => fibrin

- To differentiate between STAPH. SPECIES (S. aureus is (+))

=> These tests are EASY and CHEAP

What Molecular Methods can be used to identify bacteria? Pro of using this, and some examples?

- Study GENOME

- MOST ADVANCED and ACCURATE

- Classify bacteria into species, strains, serotypes, pathovar levels

- Examples:

+ PCR

+ DNA/RNA probe tests

+ Microarray

+ Electrophoresis

+ Proteomics

What Immunological Methods can be used to identify bacteria? When can we use this?Examples?

- Only useful for PATHOGENIC bacteria => Identify Ig or antigens

- Examples:

+ ELISA

+ RadioIA

+ FluoroIA

+ Chromatography

What are fungi?

- EUKARYOTES

- Majority = SAPROPHYTES = Live on dead organisms

- Reproduce via SPORES (not like bacteria)

- CHITIN cell wall

- Uni or Multicell

Ex. Yeast, mold, mushrooms

Codes for ID bacteria

- 1 =

- 2 =

- 3 =

- 4 =

- OBL =

- PR =

- OPP =

- Z =

- R =

- 1 = Extremely familiar

- 2 = Very familiar

- 3 = Aware of name and info

- 4 = Heard of name and know where to find info

- OBL = Obligate

- PR = Primary pathogen

- OPP = Opportunist

(not clearly different from PR)

- Z = Zoonotic

- R = Reportable

Difference between Obligate, Opportunist, Facultative, and Primary Pathogen? Important note about them?

- Obligate = ONLY FOUND in DZ host

(Obligate intracellular: can only multiple within host cells)

- Facultative intracellular - Can multiply inside AND outside cells

- Opportunist = Only cause Dz when host's IMMUNO-compromised (found always, but ony cause dz in certain circumstances)

- Primary = Cause Dz REGARDLESS of host's immune system

**Primary pathogen and Opportunist aren't clearly different => Classifying them are arguable!**

Types of Fungi - differentiate? (3)

1. YEAST:

- UNIcell

- BUDDING to divide

- May have pseudohyphae

2. MOLD:

- MULTIcell

- Extending spores ASEX/SEXUALLY into tubes (HYPHA) or cotton-wool mass (MYCELIUM)

3. DIMORPHIC FUNGI:

- Both yeast and mold forms

5 steps to Sequence of Pathogenesis

1. Enter/attach

2. Evasion of Host's Defences

3. Multiplication + Colonization

4. Damage to Host

5. Transmission to other hosts (infectious stage)

Characteristics of Bacterial Colonization?

- What determine host and organ specificity?

- Difference btw Obligate, Primary, and Opportunistic pathogen in this step?

- ADHESINS => Determine host and organ specificity

- Obligate and Primary bacterial pathogens are host and organ specific

- Opportunists are often non-host specific. However, pathogen, envi, and host factors still determine colonization.

What molecules from Bacterial cause Host Damage (4)?

- Toxins = Endotoxin and Exotoxins

- Lytic enzymes

- Inflammation from PAMPs, TLRs

- Immune-mediated

Gram-Positive Aerobic Cocci - What Bacteria are they? Their habitats? (3)

3 major genera:

1. Staphylococcus

- In MUCOSAL surfaces

- POSITIVE Catalase test - Catalase = enzyme breaks down H2O2 => Resist oxidative damage from phagocytes

2. Streptococcus

- In THROAT and UROGENITAL

- Negative catalase test

3. Enterococcus

- In INTESTINE

- Negative catalase test

Staphylococcus - Characteristics?

CHARACTERISTICS:

- CATALASE (+)

- GRAPE-like clusters

- Most are non-pathogenic, COMMENSALS of skin and exposed mucosae

=> Some become OPPORTUNISTIC PATHOGEN

- SURVIVE well in envi

- Some host specificity

- Cause PURULENT INFECTIONS and necrosis

- PATHOGENICITY: More pathogenic = COAGULASE (+) as well

Virulence factors of Staphylococcus?? FIX

- Fibronectin-binding proteins => Adhesin colonization of wound activity

- DNAs, Lipase, etc. => Host tissue penetration

- Hemolysin => Damage cell membranes

- Leucocidins => Cytolysis of leukocytes

- Enterotoxin => D+

- Toxic-shock-syndrome toxin => Superantigen that cause shock

- Coagulase => Make Fibrin shields to hide from phagocytes

- Protein A => Bind Fc in immunoglobins

- Biofilm => Shield from host defences

Chemical nature of Endotoxin?

= LPS or lipopolysaccharides

Different species and disease of Staphylococcus?

1. S. AUREUS:

- in HUMAN and some animal

- Infection: SKIN and WOUND, Local NECROSIS, PUS, abcess

- Also cause: UTIs, Bacteremia, MASTITIS, Arthrisis, BUMBLEFOOT

- Toxic SHOCK syndrome when food-borne (by enterotoxins)

- Contagious => 1 common Hospital acquired infections in the ESKAPE group

- MRSA = Methicillin-resistant S. aureus = RESISTANT TO ALL B-LACTAMS so resistant to many antibiotics!

2. S. PSEUDINTERMEDIUS, SIG (intermedius group):

- In DOGS and CATS

- Most common OPPORTUNISTIC PATHOGEN in dogs

- Similar virulence factors, pathogenesis, epidemiology like S. aureus

- Cause: PYODERMA, OTITIS, UTIs, wound, Bacteremia, vaginitis, metritis, conjunctivitis, abcess

- MRSP: Methicillin-resistant S.pseudin: MULTIRESISTANT to many antibiotics

3. S. HYICUS:

- In PIGS, affect young pigs (under 6wk)

- Morbidity: 10-90%; Mortality: 5-90%

- Cause EXUDATIVE EPIDERMITIS and non-pruritic pustules (Greasy Pig Dz)

How do you differentiate or Dx between Staph species?

- Use SMEAR and GRAM stain of clinical materials

- Culture and ID within 1 day

- Use MALDI-TOF MS to differentiate (a molecular test)

- Other methods: mecA for MRSA and RSP

- Antimicrobial susceptibiity test (1 day)

How to treat and prevent Staph infection?

- TX: Antimicrobials AND eliminating primary cause (as it's opportunistic)

- Aseptic SX, wound hygiene

- MASTITIS: Prevent by detecting subclinical infections, hygiene, dry cow therapy

- Susceptibility testing because there's frequent antimicrobial resistance!

Characteristics of Streptococcus?

- Chains of cocci

- Commensals of MUCOUS MEMBRANES (NOT skin)

- DO NOT SURVIVE well in envi

- Fastidious

- Strong Host SPECIFICITY

- Cause PYOGENIC INFECTIONS

Virulence factors of strep - FIX

Different species of Streptococcus? - FIX

1. S. EQUI subsp EQUI

- In HORSES, PRIMARY pathogen

- Cause STRANGLES

- Highly contagious and morbid (Mortality: 10%)

- Abcess in LNs OF HEAD/NECK

- Transmission via DISCHARGE + GUTTURAL POUCH carrier

- TX: Isolation, quarantine, clean, penicillin

- Vax available but not 100% effective

2. S. EQUI subsp ZOOEPIDEMICUS

- In HORSES, OPPORTUNIST pathogen (meaning will only cause DZ when there's immuno-suppress)

- Cause PURULENT INFECTION, 2nd PNEUMONIA, septicemia, abcess, wounds, UTI, mastitis,

FIX THIS

3. S. AGALACTIAE

- In CATTLE, PRIMARY PATHOGEN of udder

- Cause CONTAGIOUS MASTITIS

- May cause SUBCLINICAL mastitis w chronic fibrosis and atrophy

- Cause Neonatal septicemia in humans and not cows

- TX: FIX

4. S. SUIS

- In PIGS and HUMANS, PRIMARY Pathogen

- In TONSILS of carriers

- Cause SEPTICEMIA in WEANER pigs

FIX THIS ONE

5. S. CANIS:

- In CATS/DOGS, OPPORTUNISTIC

- Cause PURULENT INFECTIONS

- Minor pathogen, Cause: UTI, wound infection, ... FIX

How to DX Streptococcus?

- Smear and Gram stain

- Culture and ID

- Antimicrobial susceptibility testing usually NOT NEEDED!

- Need to use:

+ Transport media

+ Lancefield serogrouping

+ Hemolysis ?

How to prevent and treat Streptococcus? - FIX

Characteristics of Enterococcus?- FIX (add last slide in)

- FACULTATIVE ANAEROBES

- Low-grade OPPORTUNIST

- INHABIT GI tract, tolerate bile

- Cause diverse GI infections

- 2nd Infections are: Mastitis, UTIs, Wound infections

- Cause NOSOCOMIAL/hospital acquired dz (ESKAPE)

Different species of Enterococcus (3) - FIX

1. E. FAECALIS:

Answer the questions at the end of slide? AND end of notes?

Lec: GRAM POSITIVE AEROBIC RODS: Characteristics and Genera? How to Dx? - FIX!!!

2 groups: (second group is Mycolata)

This group has 4 genera

- Diverse morph and genetics

- THICK CELL WALL, susceptible to PENICILLIN G

- Some are agents for zoonoses, septicemia, bacteremia

- Rod-shaped

1. BACILLUS

- In Human, animals, soil

2. LISTERIA:

- In Throat and Urogenital tract

3. TRUEPERELLA:

- In Intestine

- Same order as 4: Actinomycetales

4. ACTINOMYCES:

- In Mouth flora

- Same order as 3: Actinomycetales

DX:

- GIEMSA stain => Pink capsule

Bacillus bacteria: Characteristics, Virulence, Pathology, and Prevention/Tx?

- Large gram (+) ROD

- OBLIGATE Pathogens

- FORM SPORES

- AEROBIC, fast growing

- Mostly saprophytes (anthrax)

- Skin contaminant

- REPORTABLE, ZOONOTIC DISEASE!

VIRULENCE:

- Highly resistance endospore/capsule => ANTIPHAGOCYTIC

- Toxins to phagocytes:

+ PA: PROTECTIVE ANTIGEN = make pores for transportation of the other toxins

+ EF: EDEMA FACTOR = Perinuclear endosomal membrane factor

+ LF = LETHAL FACTOR = Affects cellular activities and apoptosis

- Release pro-inflammatory cytokines from macrophages

- These toxins help proliferates bacteria in body => Cause SEPTICEMIA

PATHOLOGY: Cause:

- Septicemia => Sudden death (Ruminants)

- No blood clotting => Hemorrhage

- Large, dark spleen (Ruminants)

- Enlarged LN (Ruminants)

- Marked localized edema (Dogs, swine)

- BIRDS UNAFFECTED

TX:

- DX quickly => Dispose carcasses safely (burning)

- DRUGS: Penicillin G, aminopenicillin, macrolides

- VACCINATE endemic regions

=> IM/SubQ = excellent

3 species of Bacillus?

3 Species:

1. B. ANTHRACIS: - MOST IMPORTANT

- In human, herbivores, soil

- Zoonotic

- REPORTABLE in Canada

- SPORULATION IN AIR (so don't open carcass!)

- Spores can PERSIST DECADES in the ground!

- Infection: ANTHRAX (animals and humans), fatal contagious in ruminants

2. B. CEREUS:

- In Humans (food, soil, water), cattle

- Infection: Mastitis, abortion, food poison

3. PAENIBACILLUS LARVAE:

- in BEES

=> American Foulbrood Dz

Characteristics of Anthrax in Canada? In Humans? How to dispose of anthrax carcasses?

- RARE and REPORTABLE in Canada

- ENDEMIC in Wood Buffalo National park

- From SPORES in SOIL from DEAD ANIMALS from anthrax

=> Why you should NEVER OPEN CARCASS OF ANTHRAX!

=> Dispose viz BURNING + FORMALDEHYDE >10%

HUMANS:

- Cutaneous = Woolsorter's dz (malignant carbuncle)

- Aerogenous (air) = Pulmonary anthrax (used in bioterrorism)

- Oral = Intestinal and Oropharyngeal anthrax

Listeria: Characteristics, pathogenesis, consequence of Dz in animals/humans, DX, TX and Prevent

= Listeria monocytogenes

- OPPORTUNISTIC

- ZOONOTIC Dz: Contaminate human food => outbreak (usually FOOD-BORNE)

- Gram (+) Coccobacillus - ROD

- AEROBIC

- HEMOLYSIS

- SAPROPHYTIC

- Can tolerate pH low (5.5) => Grow in bad silage = SILAGE DZ

- Still grows slowly at low temp (4C) => Psychrophilic

- ASYMPTOMATIC ENTERIC Carriers

PATHOGENESIS:

- Penetrate epithelial cells

- Escape phagolysosome

- Moves from cell to cells directly

- Remain cellular => Escape immune response

DISEASE

- Cause: NECROSIS, micro-ABSCESS, SEPTICEMIA

- Mainly in ruminants: NEURO ENCEPHALITIS (trigeminal nerve + brainstem abscess), ABORTION (septicemia -> transplacental)

- Abortion in chinchillas

- Mastitis, keratoconjunctivitis

- Humans: Meningitis, abortion, septicemia (usually weak = predisposed), MORTALITY 30%

DX:

- Clinical signs

- Culture/pathology (histology of encephalitis)

TX: Treat in early stage: Penicillin, ampicillin, tetracyclins

PREVENT: Check silage quality + VAX

SAPROPHYTIC meaning

Feed off dead organic matter

Trueperella: Characteristics, Consequence of Dz, Virulence, DX, Prevention

= Trueperella pyogenes

- Gram (+) ROD

- AEROBIC but FACULTATIVE ANAEROBIC, Slow growing (48h)

- Live in SKIN and EXPOSED MUCOSA and INTESTINE of ruminants + pigs

- OPPORTUNISTIC

- HEMOLYSIS

- Survive in envi then multiples in host

DISEASE:

- PURULENT INFECTION (chronic)

- Disseminate => BACTEREMIA

- Mixed w other anaerobic bacteria => Toxin synergy

- Infections: METRITIS, Bacteremia caused ENDOCARDITIS, Abscesses, Abortion, Arthritis

- Cause: Footrot, wounds, navel infections, pneumonia

VIRULENCE: Poorly understood

DX:

- Smear

- Culture

PREVENTION:

- Avoid primary cause/lesion (as it's OPP)

- NO VACCINE!

Actinomyces: Characteristics, Consequence of Dz, DX, TX

- BRANCHING FILAMENT

- Live in MOUTH FLORA

- Cause CHRONIC INFECTION w mouth, bites

- In colonies surrounded by SULFUR GRANULES (calcifed macrophages)

DISEASE:

- In Cow: LUMPY JAW DZ: Mandible Suppurative osteomyelitis (trauma/teething associated)

DX: Gram-stain, sulfur granules

TX:

- Since chronic and walled-off micro-colonies => Hard to treat

- SX + Antimicrobials long-term

Go through questions!!!

GRAM-POSITIVE AEROBIC RODS - Mycolata group - Characteristics and genera

MYCOLATA GROUP:

- Has lipid-rich outer envelope w mycolic acid

- FACULTATIVE INTRACELLULAR, can survive out or inside macrophages

- Cause GRANULOMATOUS inflammation => Chronic infection

- Cellular Type 1 Immunity => Can do gamma interferon test/serology to check

4 Genera:

1. Corynebacterium:

- In Human, Animals, Ruminants

2. Mycobacterium:

- In Human, birds, ruminants, horse, pigs

3. Rhodococcus:

- in Herbivore manure-contaminated soil

Corynebacterium - Characteristics, Dx, Infection, and Prevention/Tx

- Gram (+) rod, small, PLEIOMORPHIC (coccoid or club or rod shape)

- AEROBIC, takes 1-2d to grow

- COMMENSALs in mm. and skin

- OPP pathogen, ZOONOTIC, HOST SPECIFIC

- Cause: PYOGENIC INFECTIONS, Pseudotuberculosis => CASEOUS LYMPHADENITIS

- ONION RING STRUCTURE = typical of this dz

- Infection from: Wound contamination, sheering, ticks

- Infect other animals in the herd

DX:

- PE

- Pathology, culture

- SEROLOGY and BLOOD GAMMA INTERFERON TEST

TX/Prevent:

- Antibiotics: Problem w PENETRATION in vivo (as it's facultative intracellular) + Resistance => Not efficient

- Eradication through CULLING based on blood tests

- Hygiene and isolate infected

- VACCINE (partial protection) => Side effect: Abscess

Check all slides and see the "infection" part - meaning how the animal can be infected w the bacteria! (and not mean "what infections this bacteria cause)

Mycobacterium - Characteristics, Cause what, Species

- WEAKLY Gram (+) rod, aerobic

- Has LIPIDS in cell wall => ACID-FAST STAIN

- SURVIVE WELL in envi

- FACULTATIVE INTRACELLULAR

- Many species! (saprophytic, opp, obligate)

- SLOW growing (24h to divide, WEEKS to isolate)

- Cause: Chronic GRANULOMATOUS infections

Many species:

1. M. tuberculosis => Human, primates

2. M. bovis => Cattle, human, ruminants, horse, pigs

3. M. avium => Birds, ruminants (paratuberculosis)

Mycobacterium bovis - Characteristics, hosts, pathogenesis, outcome dependent on what?, Fate in Canada, DX, TX, Prevention

- OBLIGATE, REPORTABLE, ZOONOTIC Dz

- Human => Turn to M. tuberculosis

- Wildlife and Domestic animals => M. bovis

- WILDLIFE = RESEVOIR for domestic

- Cause: GRANULOMA

PATHOGENESIS:

- Airway/ingestion infection

=> Innate host control:

- Local multiplication

- Macrophages uptake => bacteria survive in macrophages => activate TH1 response w gamma interferron => Form tubercle and chronic granulomatous activation

- LN migration => Lymphadenitis

=> Containment

==> Cause Acute Dz

==> OR Spontaneous healing

=> Latency

=> Reactivation

=> Dz/Transmission

- Outcome is dependent on CELLULAR IMMUNITY

CANADA:

- Persist in WOOD BUFFALO NATIONAL PARK

- Some outbreaks detected from meat inspection surveillance

DX:

- Detected at slaughter

- Tuberculin skin test => Slaughter

- PE and Pathology

- ACID FAST-STAIN

- PCR, Slow culture

- DNA methods

TX:

- Culling

- Human: Amtimicrobials

- Other mycobacteria: use fluoroquinolones, macrolides, minocycline etc.

PREVENT:

- Slaughter surveillance, meat inspect

- Test-slaughter (DTH, gamma interferon assay)

- Quarantine, retesting

- MOVEMENT controls

- Hygiene and Milk pasteurize

- Vaccine

Mycobacterium avium complex - Characteristics, hosts, Prevention

= AVIAN TUBERCULOSIS = CHRONIC infection

- PRIMARY, ZOONOTIC

- Infected via AIR, intesting, dissemination

- Prevention similar to M. Tuberculosis

Mycobacterium marinum - Characteristics, hosts, Cause what?

- OPP, ZOONOTIC, saprophytic

- Infected via SOIL/WATER

- FAST GROWING

- Cause: Fish tank granuloma, pyogranulomatous skin lesions

Mycobacterium avium sbs paratuberculosis (MAP) - Characteristics, hosts, where it reside, cause what, factors affecting infection?

Epidemiology? DX? TX and Prevent?Clostridium

= JOHNE's Dz

- AEROBIC ROD

- Grow 3-6wk on LIPID RICH media w mycobactin

- ACID-FAST

- Infection via MILK, pasture, utero

- Reside in INTESTINAL MACROPHAGES and LOCAL LNs

- Last LONG - several months, can delay for years

- Cause: GRANULOMATOUS ENTERITIS, CACHEXIA

- Factors affecting: HIGH MILK YIELD, dose, breed, age at infection, calving

EPIDEMIOLOGY:

- Asymptomatic shedders (milk, feces)

- Has genetic predisposition

Check vinson's slides, improve notes too

(Lab 5.3) Extracellular vs Facultative intracellular Bacteria: Differences in:

- Cell type habitate

- Disease process

- Illness length

- Immunity

- Vaccination

- Antibiotics

EXTRACELLULAR:

- Cell types: Neutrophils

- Disease: Purulent

- Length: Short/Acute

- Immunity: Humoral, Th2

- Vax: Bacterin, toxoids

- Antibiotics: Effective, based on susceptibility

FACULTATIVE INTRACELLULAR

- Cell: Macrophages

- Dz: Granulomatous

- Length: Long/Chronic

- Immunity: Cellular, Th1

- Vax: Live attenuated (not complete)

- Antibiotics: Depends on penetration into host cells!

What diseases are REPORTABLE? - FIX

- Write out the list!!!

Clostridium - Characteristics and Pathogens - FIX

CHARACTERISTICS:

- Fix

- Aerotolerant

- Can survive low O2 envi

3 SUBGROUPS:

1. C. difficile, C. perfringens (A-E) => Intestine-formed toxins => Blood => TOXEMIA

- Toxin: ENTEROTOXIN

2. C. septicum, perfringens (A), chauvoei, sordellii => Invasive, Gas-gangrene-producing

- Toxin: HISTOTOXIN

3. C. tetani, botulinum => Non-invasive, colonize host limitedly

- Toxin: NEUROTOXIN

Clostridium Perfringens - Characteristics, Dx, Tx, Control

- PRIMARY PATHOGEN, OPPORTUNIST

- Widespread in intestine, via FECAL contamination

- FASTEST GROWING bacteria

- Some are lethal, mostly PORE-FORMING

- 7 types

- Type A also cause HISTOTOXIC GAS GANGRENE Mastitis (from wound infections)

DX:

- Swab/fluids send to lab

- Gram stain + Culture under anaerobic conditions => Confirm for anaerobes

- MALDI-TOF to confirm organism

TREAT:

- DEBRIDING (if wound) + rinse and drain

- ANTIBIOTICS

PREVENT:

- Antimicrobials to broilers (prophylaxis)

- VAX (toxoid, for pulpu kidney dz)

- Hygiene

7 types of C. perfringens - Their Dz and Toxins? - FIX

1. Type A:

- Mostly commensals - Normally found in gut

- Usually produce Alpha toxin = Normal

- If produce other toxin => DISEASE:

+ Hemorrhagic necrotizing enteritis in dogs and foals (NetF Toxin)

+ Abomasitis in calves

- Also cause: HISTOTOXIC GAS GANGRENE Mastitis (from wound infections)

....

Clostridium Difficile - Characteristics, Pathogenicity, Tx, Control - FIX

- Common in HORSES, pigs, rabbits, guinea pigs, humans

- ZOONOTIC, PRIMARY pathogen

- Difficult to culture!

??? Notes about antibiotics?

PATHOGENICITY:

- SPORES => transmit => Stomach, bile acids

- HX OF ANTIBIOTICS => compromise normal gut flora => C.difficile grow rapidly!

- 2 toxins: A = ENTERO/CYTOtoxin; B = CYTOtoxin

- Virulent type has 027 additional toxin gene = More toxin production!

DISEASE:

- Major HOSPITAL ACQUIRED infections in humans

- From meat

- Cause milder dz => COLITIS => TOXEMIA

- Horses: also have TYPHLOCOLITIS (cecum + colon)

DX: ??

TX: (from lab so fix!)

- Eliminate causing factor (the antibiotics used to begin with)

- Probiotics supplement

- Antibiotics may help but some may aggrevate C. difficile (?)

Blackleg Dz - Agent, Pathogenesis, Dx, Tx? - fix

- C. Chauvoei (also C. septicum and C. novyi)

PATHOGENESIS:

- INGEST spores from soil/other animals

=> Reach liver and intestinal blood (?)

=> Go dormant in muscles

- Trauma that cause ANOXIA (reduce O2 pressure in muscle) => ACTIVATE latent growth of spores

- Spores' toxin => ACUTE, INFECTIOUS, NECROTIZING MYOSITIS + SYSTEMIC TOXEMIA in calves in summer => Death

- They produce gas => CREPITATION under skin

- TX?

DX: (from lab 5.4) - fix

- Send the animal OR piece of affected muscles

- Smear + Stain w SPECIFIC ANTIBODIES for C.c

- Immunofluorescene

- PCR

- Culture

PREVENT:

- VAX (bacterial and toxoid) = most efficient (?)

Malignant oedema/Gas gangrene - Agent, Pathogenesis, Dx, Tx? - fix

-

What's pulpy kidney disease? - FIX

Tetanus - Agent, Pathogenesis, Signs, Dx, Tx? - fix

- C. tetani

- ZOONOTIC: HORSE > Humans > Others (ALL species can have this)

- Infect at DEEP WOUNDS (ex. castration wounds in horses)

- From soil and animal intestine, esp. HORSE MANURE

- Survive as SPORES (Tennis-racket shape spores)

PATHOGENESIS

- Produce TETANOSPASMIN toxin at infection site (= cytolysin)

- Migrate via ascending peripheral nerves to CNS => Inhibitory neuron => INHIBIT the release of inhibitory NT (GABA and glycin)

=> Make motor neurons fire endlessly => SPASMS

SIGNS:

- STIFF PARALYSIS

- Stiff tail, neck, ears

- Muscular spasms

- Protruding third eyelid

DX: fix

- Clinical signs

- Toxin test: mice (rarely done)

TX:

- Calm, darkness, silence

- MUSCLE RELAXANTS, artificial respiration

- ANTISERUM => Stop toxin migration to nerves

- Antibiotics

- Artificial O2 if needed

PREVENT

- VAX (Toxoid) = EFFECTIVE in human and horses (not others)

- Wound hygiene

- Avoid trauma

Botulism - Agent, Pathogenesis, Dx, Tx?

- PRIMARY Pathogen

- Everywhere in the environment

- MOST POTENT TOXIN = BOTULINUM - from anaerobic spoilage of decaying animals/plant

+ 1ug = Kill a person!

+ Similar to Tetanospasmin

PATHOGENESIS:

- INGESTION of agent => Cross intestinal mucosa => Go to PERIPHERAL nerves

- Target Cholinergic cells @NMJ

- INHIBIT Ach release

- Cause peripheral effects

DISEASE:

- Mostly INTOXICATION (ingestion) => FLACCID PARALYSIS

- Also cause TOXICO-INFECTIOUS: Produced in intestine by vegetative bacteria, ex, in chickens

- Also cause WOUND BOTULISM: Rare, pathogenesis like tetanus. Ex. Navel infections, drug addicts

DX:

- Toxin test: Mouse, ELISA

- Mouse test = MOST SENSITIVE: Botulinum toxin => Wasp-waist (diaphragmatic paralysis) in mice

- PCR - can have false positive

A positive usage for Botulinum toxin?

= BOTOX

Explain pathogenesis of Botulism Type E in Great Lakes

- Putrefaction + Less O2 => Grow C.botulinum

- Fish eats toxin from feed

=> Concentrated along food chain

- Birds pick up slow + dead fish => DEATH

REVIEW QUESTION

Lab 5.4: Importance of Plasmids for C. Perfingens?

= Circular DNA, carrying extra genes (ex. for virulence and antiobiotic resistance)

- Plasmids are NOT required for normal bacterial function

- Genes from plasmids are NOT always actively expressed

- Plasmids can be copied and transferred btw bacteria (same or different species!)

Difference between Tetanus and Botulism

- Agent different

- Toxin different

- Entry different (Tetanus via wound, Botulism PO)

- Route and Target different (Tetanus via peripheral nerves => CNS, Botulism via intestine => peripheral NMJs)

- Mechanism different (Tetanus inhibits release of inhibitory NT, Botulism inhibits release of Ach)

- Signs different (Tetanus STILL paralysis, Botulism FLACCID paralysis)

CATCH UP LEC 5.5 5.6

5.7: Pasteurellaceae - Characteristics, host, virulence factor, reside @?

- Gram (-) bacteria

- (+) for Cytochrome C Oxidase test (does produce this)

- Facultative ANAEROBIC

- Nutritionally fastidious, takes 2 days to grow

- 3 Genera: Pasteurella, Mannheimia, Actinobacillus

- Reside at MUCOSAL surfaces (URT, Mouth), survive poorly in environment

- EXTRA-CELL pathogen

- Host specific, broad range, from commensals to primary - NOT HUMAN

- 16 O antigen types

- Cause SEPTICEMIA +/- PNEUMONIA

- Virulence factors: Capsule, adhesins, iron-acquisition system, TOXIN: RTX, PMT, ENDOTOXIN

Pasteurella multocida - Characterisitcs? Which type cause what disease? Dx? Treat and Prevent?

- OPPORTUNIST-PRIMARY PATHOGEN, ZOONOTIC (via bites)

- Normally inhabit Upper Resp Tract (URT) and Mouth of animals (NOT HUMAN)

- Haemorrhagic Septicemia = Asian/African cattle (Type B, E)

- Fowl cholera = Birds septicemia (Type A)

- Swine Suppurative bronchopneumonia = Swine, BRDC Cattle (Type A) (usually occurs with Mycoplasma)

- Rabbit "snuffles" complex = Rabbit's Otitis, rhinitis, septicemia, pneumonia, abscess (Type A)

- Cat/dog bite abscess = Anaerobes

- Swine Atrophic rhinitis = Swine URT infection (twisted snout, turbinate atrophy), PMT Toxin (Type D)

DX: Culture + Oxidase MALDI-TOF

TREAT/PREVENT:

- Antimicrobial prophylaxis, beta-lactams, sulphonamide trimethoprim (some resistance)

- VAX TURKEYS w bacterins

- VAX for Swine rhinitis w PMT toxoids

- Manage Dz!

Mannheimia haemolytica - Characteristic, infection, pathogenesis/virulence, predisposing factors, DX, TX and Prevent

- Within Pasteurellaceae group

- Normally seen in upper resp of cattle

- OPPORTUNIST => PRIMARY PATHOGEN

- Several serotypes with variable virulence (A1 = MOST VIRULENT)

INFECTION:

- Cause RUMINANT PNEUMONIA

- Often mix w other bacteria: Mycoplasma, P. multocida, Histophilus somni

- Main pathogen in BRDC in CATTLE

- Cause SEPTICEMIA + PNEUMONIA SHEEP

PATHOGENESIS/VIRULENCE:

- Fimbrial and afrimbial ADHESINS

- Bacterial CAPSULE resistant to phagocytosis => Evade host's immune

- LEUKOTOXIN RTX => Kill alveolar macrophages and neutrophils PMNs

- IRON acquisition system

PREDISPOSING FACTORS:

- Viral agents: IBR, BVD, Corona

- Environmental + Host factors: Weaning, immunity, transporation, carriers, air/water quality

DX: Culture (slow) + MALDI-TOF

TX and PREVENTION:

- Control predisposing factors

- Precondition: Adapt to bunk feed, dehorn, socialize, deworm, vaccines for other bacteria, avoid stress when transport

- Prophylactic antibiotics (resistance tho!)

- Early recognition + treat, hygiene

2 diseases and agents of Actinobacillus? (toxin, disease, DX, Tx, prevent)

1. A. PEUROPNEUMONIAE:

- Live in Swine URT

- Cause Fibrino-haemorrhagic pleuropneumonia (peracute-chronic) in SWINE (usually mixed flora with other bacteria)

- OPP => PRIMARY

- Complex/fastidious nutrition, need NAD

- Trigger by stress

- Ranges from healthy carriers to chronic and peracut Dz

- VIRULENCE:

+ Iron-scavenging system

+ 16-18 serotypes/capsules, vary in virulence

+ TOXIN: 4 types RTX = Apx

+ ALL serotypes express Apx4

+ Virulent serotypes express Apx1 and 2 => Cytotoxic (macrophages) + Endotoxic (inflammation)

- DX: MALDI-TOF

- TX/PREVENT: Antibiotics, Vax toxoids and bacterins, Manage (don't mix pigs w different serotypes)

2. A. SUIS:

- OPPORTUNIST

- SEPTICEMIA and PNEUMONIA swine, broader host range

- Mortality in high health status herds

- Pathogenesis: Toxin Apx1 and 2, LPS and capsule important

- Same TX/PREVENT as above

Haemophilus - Characteristics?

2 diseases and agents of Haemophilus? (toxin, disease, Tx, prevent)

- Gram (-), coccobacilli, 'blood-loving"

- Non hemolytic, Fastidious, needs NAD or Haemin

- Commensals of MUCOSA (URT)

1. GLAESSERELLA H. PARASUIS:

- CATALASE (+)

- Cause Glasser's dz: POLYEROSITIS, polyarthritis, menignitis, pneumonia

- Higher health = more prone to this

- Fastidious, grow slowly

- Manage + Vaccine (AUTOGENOUS BACTERINS)

- TX w antibiotics

2. HISTOPHILUS SOMNI:

- Live in GENITAL TRACT cattle

- Cause CATTLE: SEPTICEMIA + PNEUMONIA + Myocradial abscesses + Endometritis + BRDC

- Cause SHEEP: SEPTICEMIA, Mastitis, POLYARTHRITIS

- CONTROL: VAX

- TX: Anbitiotics

Bordetella bronchiseptica - Characteristics, Infection Types, Pathogenesis, Dx and Tx/prevent

- Cause dz in immuno-compromised patients

- PRIMARY + ZOONOTIC

INFECTION TYPES:

- Dog & Cat's Kennel cough, infectious tracheobronchitis

- Pig: Atrophic ehinitis predisposition, pneumonia

- Rabbis, guinea, horses: URT infections, tracheobronchitis

PATHOGENESIS:

- CILIOSTASIS: Fimbria + Haemaglutinin attaches to ciliated epithelium @ tracheobronchial; then Toxin destroys them

- Adenylate cyclase-hemolysin enters cell => Inhibits phagocytosis + cause Neutrophil (PMNs) apoptosis

=> Persistent chronic TRACHEAL INFLAMMATION + COUGHING

- In pigs: Dermonecrotic toxin + Osteotoxin => Osteosynthesis inhibition => Atrophic rhinitis in pigs

DX: Tracheal aspirate, culture, MALDI-TOF

TX/PREVENT:

- Vaccine

- Long antimicrobials treatment

- Hygiene

- Isolate case

Taylorella equigenitalis - Characteristics and Dx

- PRIMARY + REPORTABLE

- Never found in Canada, but currently absent in US as well

- Cause CONTAGIOUS EQUINE METRITIS (CEM) => Temporary infertility in mares

- DX: Culture and PCR genital tract for carrier state. Need specific medium. Carriers are usually HEALTHY!

5.8: Brucella bacteria - Characteristics? Types of sub species (5) and Zoonotic potential

- Small GRAM NEGATIVE coccobacilli

- Acid-fast stain

- AEROBES but facultative anaerobes, CAPNOPHILIC

- Host-specific

- Facultative INTRACELULAR

- Target: REPRODUCTIVE organs

- ZOONOTIC

- Cause UNDULANT FEVER HUMANS

TYPES

- B. Abortus: Cattle, bison => In Wood Buffalo National Park (REPORTABLE)

- B. suis: Caribou (free-ranging) (REPORTABLE)

- B. canis: Dogs and humans (rare)

- B. ovis: Sheep (rare)

- B. melitensis: Sheep, goat (not in Canada) (REPORTABLE)

ALL except B. ovis are ZOONOTIC

- Resevoirs: Infected animals and products

- Transmission: Ingestion, skin breaks, airborne (labs)

- Incubation: 2-4wks

Brucella abortus - Characteristics, pathogenesis, infection, explain Surveillance program?

- OBLIGATE, ZOONOTIC, REPORTABLE

- In cattle

- Eradicated in Canada, except Wood National Buffalo Park

- Non-motile, non-capsulated, non-spore => SURVIVE IN ENVIRONMENT FOR MONTHS (but doesn't grow)

- Transmission: Ingestion, wounds, nasal and oral MUCOSAE

PATHOGENESIS:

- Invade epithelial cells via MUCOSAL invasion and Intestine M-cells

- Survive in phagocytes and non-phagocytic cells => Block phagosome-lysosome infusions

- Persistent infection of reticulo-endothelial system

- Can reach placenta via macrophages => Use erythritol => Mass multiplication in placenta => PLACENTITIS

INFECTION:

- CONTAGIOUS ABORTION in cattle (abort once then becomes carrier, shed at parturition)

- Epididymitis + ORCHITIS in bulls => Sterile

- CALVES: <6mth = clear, >6mth = persist for life

SURVEILLANCE:

- CFIA Bovine surveillance system BSS for brucellosis

- Random sampling at slaughter (esp. around Wood Buffalo), at import/export and AI

- DX Tests: RAPID BUFFERED PLATE TEST (cheap, but not specific)

=> If test (+) => Need to do 2nd test: SERUM AGGLUTINATION + COMPLEMENT FIXATION TEST ($, less sensitive, more specific) to confirm

- If still (+) => Quarantine, further tests, destroy animals => Compensate producers

Brucella suis - Characteristics, infection, Dx?

- OBLIGATE, ZOONOTIC, REPORTABLE

- 4 strains:

+ Biovar 1-3 = Swine

+ Biovar 4 = Reindeer & Caribou***

- Prevalent in South America, EU, Asia

=> CFIA does SEROLOGICAL SCREENING at slaughters

INFECTION:

- Chronic INFLAMMATION of REPRO tract

- Stillbirth, Neonatal mortality

- Temporar sterile

DX: Serology: ROSE-BENGAL PLATE AGGLUTINATION, ELISA => Culture + PCR

Brucella canis - Characteristics, infection, Dx and Tx?

- OBLIGATE, ZOONOTIC (rare in humans)

- In free-ranging dogs

INFECTION:

- Chronic, persistent reticuloendothelial infection

- Bacteremia

- VERTEBRAL OSTEOMYELITIS

- Abortion in late pregnancy

- Epididymitis, orchitis (pyogranulomatous inflammation in testes)

DX:

- Serology, rapid slide agglutination (RSA) (low specificity)

=> Confirm w ELISA + Agar gel immunodiffusion assay (more specific)

TX: Tetracycline LONG TERM + Aminoglycosides

Brucella ovis - Characteristics, infection, Dx?

- OBLIGATE

- Present in most all sheep countries

INFECTION:

- EPIDIDYMITIS (unilateral)

- ABORTION

- LAMB MORTALITY

- Genital lesions in rams

- Placentitis in ewes

DX:

- Bacteriological Isolation from semen, vaginal discharge, milk

- SEROLOGICAL TESTS: CFT, AGID, ELISA with SOLUBLE SURFACE ANTIGENS

Pseudomonas aeruginosa - Characteristics, virulence, diseases, Dx, Tx?

- Gram-NEGATIVE, Strictly AEROBE

- Superficial, rarely systemic

- Large genome, metabolically versatile

- Ubiquitous (everywhere) in water and soil

- OPPORTUNIST, ZOONOTIC w broad host => esp. IMMUNOCOMPROMISED HOSTS and burn patients

- Usually killed by neutrophils so Dz usually occurs in neutropenic patients

VIRULENCE:

- Alginate (slime)

- Elastases

- Hyalyronidases

- Collagenases

- Haemolysins

- Exotoxins

DISEASES:

- Dog: OTITIS externa, corneal ulcers, wounds

- Horses: CORNEAL ULCERS, infectious metritis

- Cattle: Nosocomial mastitis

- Mink: HEMORRHAGIC PNEUMONIA

- Sheep: FLEECE ROT

- Humans: Corneal ulcers, burn infectious, cystic fibrosis

DX: Fruity smell

TX:

- NO VACCINE (except in mink!)

- RESISTANT TO ANTIBIOTICS and disinfectants

- Need to do antimicrobial susceptibility testing

- Part of the ESKAPE group

Moraxella bovis - Characteristics, infection, virulence, Tx and prevent?

- Seen in pairs

- PRIMARY pathogen

- Animals carry bacteria in CONJUNCTIVA

- Spread by FLIES + Direct contact from carrier cows

- Organism host-adapted

INFECTION:

- BOVINE KERATOCONJUNCTIVITIS (pink-eye) => ulcers => blindness

- Animals don't eat well => Welfare and Production issues

- INCREASED SUNLIGHT SENSITIVITY + Darkening below eye

VIRULENCE:

- RTX HAEMOLYSIN

- Fibrinolysin

- Hyaluronidase

- Adhesive pilus => Antigenic variation

- Cause POOR IMMUNITY following infection

TX and CONTROL:

- Early Dx

- FLY CONTROL w insectivide impregnated ear tags

- Predisposing factors prevent: Cut tall grass, prevent viral infections, avoid dust and pneumonia

- Antibiotics topical, Aminoglycosides, beta-lactams, macrolides, tetracyclines

- NO VACCINE!

Bartonella - Characteristics, infection, vector, virulence, diseases, Dx, Tx

- Gram NEGATIVE, AEROBIC coccobacilli, INTRACELLULAR (in RBCs, affect Bascular Endothelium)

- Numerous species, some highly host adapted

- Vector: FLEAS and TICKS

- Cause persistent, SUBCLINICAL BACTEREMIA

VIRULENCE:

- TYPE 4 secretion system

- Trimeric autotransporter

- Hemin binding protein

DISEASES:

1. B. Henselae: Cats, dogs, HUMANS => Bacteremia and CAT SCRATCH FEVER

- ZOONOTIC, OPPORTUNIST

- In feral cats => asymptomatic bacteremia (esp. young kittens)

- In humans: Erythematous lesion => Fever, bacilliary angiomatosis

- Present in RBC + ENDOTHELIAL CELLS

- DX: PCR blood

- TX: Antibiotics that can penetrate host cells (tetracycline, flutoquinolones) - poor response tho (so only use for immunocompromised humans; Will recur in cats)

- PREVENT: Hygiene, flea control

2. B. Clarridgeiae: Cats, dogs only => Bacteremia and Cat scratch fever

DX:

- DIFFICULT TO CULTURE (weeks on agar)

- Seen in tissues w Silver stains

- PCR from whole blood

Acinetobacter baumannii - Characteristics

- OPPORTUNIST (low-grade)

- Part of ESKAPE

- Commensal in environment

- Resistant to most antimicrobials; acquire resistant genes via reproduction

- IMPORTANT NOSOCOMIAL PATHOGEN (from Iraq and Afghanistan soldiers, vet hospitals)

Capnocytophaga canimorsus - Characteristics, predisposing factors, Dx, and Tx

- OPPORTUNIST, ZOONOTIC

- Slow growing, fastidious GRAM NEGATIVE ROD

- In ORAL FLORA of cats and dogs

- Cause SEPTICEMIA + MENINGITIS following bite/lick in humans (not a problem in healthy patients)

PREDISPOSING FACTORS:

- Alcoholism

- Splenectomy

- Cytotoxic cancer

DX:

- PCR Dx difficult

TX:

- Long-term antibiotics w Penicillin G

What is ESKAPE?

Multidrug resistant hospital-associated pathogens

E: Enterococcus faecium

S: Staphylococcus aureus

K: Klebsiella pneumoniae

A: Acinetobacter baumannii

P: Pseudomonas aeruginosa

E: Enterobacter species