Microbiology - Biological Safety Levels and Routes of Transmission

Part of Microbio Epidemiology pt. 2

BSL 1 microbes?

Bacillus subtilis, E.coli, micrococcus luteus

BSL-1

nonpathogens → universal precautions only

BSL-2

direct contact pathogens. NOT airborne. Universal precautions, no direct contact.

Ex: Hep B/immunodeficiency

BSL-3

aerosol transmitted pathogens. Universal precautions + work with microbes under hood. Air pressure controlled room

BSL-4

aerosol/direct contact/highly contagious/virulent pathogens.

• Positive pressure suit, ALL precautions taken

• Full air lock rooms only

• Separate building or room

How many routes of transmission?

6

Fecal-oral route

From animal’s waste product → contaminated water/food → someone’s mouth

Respiratory route

• Mucus dries out in cold weather → bacteria can attach

• Nasolacrimal duct → nasal passage → res. system

Urogenital route

• STDs

• Most commonly contracted nosocomial infection = UTI

Parenteral route

directly into body/blood through skin

Fomite route

touch non-animate object (chair/table/door knob)

Nosocomial route

Hospital acquired infection