Question book 2 Flashcards
Which of the following must be handled in a safety cabinet at containment level 3?
serum from IVDU Toxoplasma serology Sputum for mycobacterial culture Blood from HBV positive patient Blood cultures from patient with fever with recent travel abroad
Sputum for mycobacterial culture
Class II biosafety cabinet, in Containment lab 3
31 year old with suspected TB. Sputum sample sent to the lab
Which statement is true about the sample
ZN stain components release toxic fumes
Auramine stain components release toxic fumes
Sputum should be prepared in class I biosafety cabinet
Sputum should be prepared in class II biosafety cabinet
Sputum should be prepared in class III biosafety cabinet
Sputum should be prepared in class II biosafety cabinet
Mycobacterium TB is a Containment level 3 agent, but only requires prep in Class II cabinet.
Class 4 pathogens eg Ebola, require Class III cabinet which is totally enclosed.
Class I biosafety protects users, but risk of specimen contamination
Class II biosafety protects users and specimen
Class III is fully enclosed, with fixed gloves
What are examples of stains used to help identify mycobacterial species?
ZN - uses carbol fuchsin to stain AFB red, then alcohol to wash, and then methylene blue counterstain
Auramine
Modified Kinyoun cold stain
Which one of these is a mandatory requirement for a CL3 lab?
high efficiency particulate air inlet laminated floor sealable for fumigation shower facilities air lock
sealable for fumigation
HEPA filter required on air leeaving lab, but no filters required on air entering the lab
What standard must packaging adhere to when sending sample by courier?
UN2814 UN2900 UN3291 UN3373 P650
UN3373 - suitable for most blood samples/ sputum whereby the specimen in its current form is unlikely to be life-threatening to courier
UN2814 - used when transporting high consequence pathogens eg brucella, ebola
Samples from HBV patient sent to lab for investigation. What is minimum laboratory safety criteria for processing these samples?
CL 1 CL2 CL 3 Class 2 safety cabinet Class 3 safety cabinet
CL2 - needs higher containment level to reduce risk of lab related injuries
Blood from HBV patient spilled in lab.
What is the best method for disinfection of the blood spill?
Phenolic compounds Alcohol Glutaraldehyde Hypochlorite Peroxymonosulphate
Peroxymonosulphate
Chlorine bleach products often used, but most of these arent registered with regulatory bodies to monitor use
CSF sample for CJD spilled on bench.
What is the best method for disinfection of the spill?
Phenolic compounds Alcohol Glutaraldehyde Hypochlorite Peroxymonosulphate
Hypochlorite
Rest of compounds have no activity, or actually stabilise the prion
When is it recommended to use formaldehyde for decontamination?
Bench top decontamination
Cleaning floor of laboratory
Fumigation
Cleaning of safety cabinets after fungal manipulation
Fumigation - it is the most commonly used substance for this. Requires prolonged time eg 12 hours room sealed over night. Formaldehyde is class 1 carcinogen, so should be avoided in other uses
What is treatment of scabies?
Topical permethrin
oral ivermectin if widespread, or Norwegian scabies
Following wedding party, reports of vomiting 24 hours later, but all report no further vomiting or diarrhoea after further 48 hours.
What is most likely cause?
Campylobacter spp Adenovirus Norovirus Bacillus cereus Staphylococcus aureus
Norovirus
Norovirus and rotavirus have very similar incubation periods of 24 hours, with quick resolution of symptoms
Campylobacter incubation normally 2-5 days
Adenovirus usually incubates 8-10 days
Staph aureus usually occurs 1-2 hours after ingestion
Bacillus cereus occurs 1-5 hours after ingestion
32 year old who works in abbatoir presents with fever.
Which organism is least likely to be the cause?
Brucella abortus Salmonella Typhi Streptococcus suis Coxiella burnetti Mycobacterium bovis
Salmonella Typhi - humans are only known reservoir
18 year old with meningococcal meningitis
Which community contacts will need prophylaxis?
Those who attended same classes as the index case that day
Those who ate lunch with the index case that day
Those who attended a party with the index case the evening before
Those who travelled on the bus next to the index case that day
Those who slept in the dormitory with index case on a field trip last week
Those who slept in the dormitory with index case on a field trip last week
Community contact is within past 7 days. Household contacts or student halls count for this
Sharing same car, sharing meal, same class all do not count
18 year old with meningococcal meningitis
Which community contacts will need prophylaxis?
Those who attended same classes as the index case that day
Those who ate lunch with the index case that day
Those who attended a party with the index case the evening before
Those who travelled on the bus next to the index case that day
Those who slept in the dormitory with index case on a field trip last week
Those who slept in the dormitory with index case on a field trip last week
Community contact is within past 7 days. Household contacts or student halls count for this
Sharing same car, sharing meal, same class all do not count
30 year old male presents with bloody diarrhoea. Shigella spp isolated, and send to reference lab for further sub-speciation.
When should this be notified to public health?
on presentation on discharge on isolating Shigella spp on receipt of reference lab sub-speciation does not need notified to public health
on presentation - bloody diarrhoea with possible common source needs notified to trigger an investigation
