11. Microbiological Quality Control for Laboratory Rodents and Lagomorphs

What test is this?

Indirect ELISA for microbial ABs

What is this test?

Direct and indirect IFA assay

What test is this?

Multiplexed fluorometric immunoassay

What is this?

Hybridization with enzyme labeled DNA probe

What is this?

Steps of PCR

What is this?

exponential amplification by PCR

What is this?

real time fluorogenic nuclease qPCR

Sterilization

elimination or inactivation of all microorganisms

PCR and serology should be used instead of culture to screen for fastidious and noncultivable microbes such as

M. pulmonis

Helicobacter

C. piliforme (Tyzzer’s)

CAR bacillus

Pneumocystsus spp.

Disinfection

elimination or inactivation of vegetative bacteria (not spores)

Quarantine

separation of newly received animals from those already in the facility, in a way that prevents potential spread of contaminants, until the health and possibly the microbial status of the animals have been determined. Also, separation of ill animals or animals potentially exposed to a disease

Stabilization

period given for newly arrived animals for physiologic, behavioral, and nutritional acclimation before their use

Quality Assurance

a program for the systematic monitoring and evaluation of the various aspects of a project, service, or facility to ensure that standards of quality are being met

Quality Control

a system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required

Axenic

no microorganisms (bubble boy)

Gnotobiotic

: animals with known microflora (defined flora)

Barrier

: facilities or equipment to protect animals from contamination (usually for SPF, immunocompromised, or especially valuable animal models)

Primary Pathogen

-disease causing potential in immunocompetent host- EXCLUDED BY SPF ANIMALS

MHV, Sendai, Salmonella, Mycoplasma, Helicobacter, C. piliforme

Include organisms of human risk

Sensitivity

: the proportion of patients with the disease who have a positive test result

Specificity

: the proportion of patients without the disease who have a negative test result

Positive Predictive Value (PPV)

: the likelihood that a patient with a positive test result has the disease

Negative Predictive Value (NPV)

: the likelihood that a patient with a negative test result is free of the disease

Prevalence

: the total number of individuals in a population who have a disease or health condition at a specific period, usually expressed as a percentage of the population.

Remember that PPV decreases when the prevalence of a disease _________

decreases

1 multiple choice option

What is the difference between the sensitivity/ specificity of screening test versus diagnostic test?

Screening tests

Generally chosen towards high sensitivity not to miss potential disease

Diagnostic tests

Chosen towards high specificity (true negatives).

Type I error

False positive

real life 🡪 no difference;

experimental🡪 difference (rejecting the real life/true Null)

Type II error

False negative

real life 🡪 difference

experimental 🡪 no difference

What is the gold standard method to rederivation?

Gold standard is now Embryo Transfer (ET) into SPF pseudopregnant females

Vertical transmission is less common with ET because the zona pelucida protects the embryo

It is rare to cross foster onto different species. Which animal species is an exception?

Rare to cross foster onto different species. Gerbil is exception (to mouse/rat moms).

Neonatal transfer of disinfected pups <3 days old to SPF foster mom has eliminated ______, ______, _____ and __________

MPV, MHV, MNV and helicobacter.

Most LAM pathogens are transmitted by direct contact

_________LDV is the notable exception (parenteral injection, cell lines)

LDV

Host adapted bacteria, enveloped viruses are not transmitted well via fomites (soiled bedding), but ____________ and certain ________ can

enteric viruses; bacteria

_______ week quarantine to allow sentinels to become infected and seroconvert

Using PCR of principals within ____ week of arrival, can reduce this to 2 weeks

4-8; one

What is used in Gamma Irradiation?

Usually cobalt-60 ionizing radiation

= BREAK NUCLEOTIDES!!

PENETRATES SOLIDS (unlike UV)

Where can UV radiation be used to disinfect? what is the wavelength with the Maximal effectiveness?

UV radiation: damages DNA (produces thymine & pyrimidine dimers) BUT NO BREAKS

Maximal effectiveness near 260nm

Surfaces and drinking water disinfection

Denaturant

break up lipids and proteins

quanternary ammonium compounds, phenolics, alcohols

Reactants

form or break covalent bonds

aldehydes, ethylene oxide

kill everything

Oxidants

oxidize particles/molecules

More effective at inactivating non-enveloped viruses, parasites and spores

Halogens, peroxygens

kill *almost everything

Most to Least Resistant:

SPP = Spores, parasites, protozoa

Myco = Mycobacterium

NEVH = Non-enveloped hydrophilic

Picornavirus

MEV, ECMV, Hepatitis A, Poliovirus, FMD

Parvovirus

F = Fungi

B = Bacteria

NEVL = Non-enveloped partial lipophilic

Adenovirus

MAdV, CAV-1, GPdV, NHPAdV

Reovirus (1-3)

Rotavirus (EDIM, IDIR)

Bluetongue

EV = Enveloped lipophilic

Paramyxovirus

Sendai, Measles, Distemper, RSV, PVM, Parainfluenza, Newcastle Dz

Coronavirus

SARS, MHV/LIVIM, SDAV, Epizoo Catarrhal Enteritis, FIP, TGE

Arenavirus

LCMV, Lassa, Guanarito Virus, Machupo Virus, Inclusion body Dz

_______ are vectors for Mycoplasma haemofelis (previously Hemobartonella muris) and Eperythrozoon coccoides

Lice

What is considered gold standard for helminths?

Exam of macerated GI tract considered gold standard for helminths

MacConkey's agar

Contains crystal violet and bile salts. Selectively inhibit the growth of gram(+) bacteria, while allowing most gram(-) bacteria to grow

Lactose-fermenting bacteria produce pink to red colonies, whereas colonies of nonlactose fermenters remain colorless

Antigen capture assays not great for infections like _______ (low antigen shed - PCR better)

MPV

bacteria/fungi induce weak Ab response (unless invasive), requires immunocompetent host susceptible to infection

Immunofluorescence Assay (IFA) is a Great ___________ assay

Great diagnostic assay (high-specificity)

1 multiple choice option

ELISA is a Great ___________ assay

Great screening assay (high-throughput)

1 multiple choice option

What makes Using colony animals as sentinels ideal?

Sentinels may bring in disease ☹ also have lag time

Must be immunocompetent

Recently weaned or young adults best (bioburden: haven't cleared infections like tyzzers or protozoa)

How much soil bedding is recommended from dirty cage?

5-15mL of bedding from each cage

Outbreak Investigation- mouse parvovirus?

If it's parvo, go dig out some mesenteric LN.

If negative in mesemteric LN for MPV then likely a false positive in the serology.

Outbreak Investigation- Rotavirus?

Rota- do not shed very long, host clears vs Norovirus- host sheds for long time and doesn't clear

How to irradicate/ contain an outbreak?

Quarantine, do 100% screen of room plus two more screens at 3-4 wk intervals

Need 2 consecutive negative 100% screens to lift quarantine.

If you can depop, do that.

Use Sterilants instead of disinfectants: Go for hydrogen peroxide, chlorine dioxide, formaldehyde gases.

OR do 2 different disinfectants so you get multiple mechanisms of kill.

THROW OUT ANYTHING THAT IS A FOMITE IF IT CAN'T BE AUTOCLAVED/STERILISED

ILAR formula number to be sampled to detect pathogen (health monitor)

Log 0.05 = number to be sampled

Log N

N = percentage of uninfected animals

Log 0.05 = 95% confidence level

Dirty bedding sentinel program will NOT effectively screen for

Sendai

Filobacter rodentium

Mycoplasma

LCMV

LDEV

Fur mites

Which of these are common contaminant of biologics?

Mycoplasma, LCMV, LDEV

You have a facility housing SCID mice. Which direction should the airflow in the animal room be?

positive

1 multiple choice option

One of your animal caretakers asks you for some Veterinary advice about their pet rat which has not been breathing right and is making a chattering sound. What should you do?

M. Pulmonis should not be dealing with the facility rats.