- Key Characteristics
- Gram-negative bacillus
- Grows at 35-37°C, faster at room temperature
- Catalase positive
- Non-motile (37°C and room temperature) Note: Y. pestis is
the only species of Yersinia that is non-motile at room
temperature)
- Oxidase negative
- Biochemical characteristics: Included in the database of most enteric identification systems, but an identification of Y. pestis must be considered presumptive until confirmed by a reference laboratory
ISOLATES WITH THE ABOVE CHARACTERISTICS SHOULD BE REPORTED TO THE
PATIENT'S PHYSICIAN AS YERSINIA SPECIES, UNABLE TO RULE-OUT PESTIS.
CONTACT YOUR STATE PUBLIC HEALTH LABORATORY FOR INSTRUCTION ABOUT
REFERRING THE ISOLATE OR SPECIMEN.
- Colony Characteristics
- Grows well on most non-selective standard laboratory media
(e.g. sheep blood, chocolate and tryptic soy agars). Pinpoint, gray
white, non-hemolytic at 24 hours, by 48 hours colonies resemble typical
enteric bacteria. After 48-72 hours, gray-white to slightly yellow
opaque raised, irregular fried egg appearance; alternatively colonies
may have a hammered copper shiny surface
- Grows more slowly than our Enterobacteriaceae at 35-37°C,
but faster than most at room temperature
- Grows on MacConkey agar appearing as small
non-lactose-fermenting colonies
- In BHI or other enriched broth, undisturbed growth is
flocculent, producing structures resembling stalactites and clumps at
the side and bottom of tubes
- Microscopic Characteristics
- A plump, Gram-negative rod (1.0-2.0 x 0.5 um)
- Bipolar staining with Wayson or Wright-Giemsa stain and may
occasionally be seen in Gram-stained preparations, more common in
specimen material than from culture. Note: Although characteristics of
Y. pestis, bipolar staining is not always observable and is not unique
for Y. pestis
- Safety
- Biosafety Level 2 for processing clinical specimens
- Biosafety Level 3 practices for all culture manipulations
that might produce aerosols
- Contact
- If you suspect the above agent, immediately contact (in the order presented):
- Drs. Lucy DesJardin and Mike Pentella at the University
Hygienic Laboratory. If they aren't readily available, ask for someone in
the Bacteriology, Virology, Serology, or Molecular laboratory.
319.335.4500 or 1.800.421.IOWA(4692)
- University Hygienic Laboratory Duty Officer
319.335.4500 or 319.530.5981
- As a final resort, the following 24-hour emergency hotlines
have been established:
Iowa Public Health Emergency Terrorism/Disaster Notification Hotline
1.866.834.9671
Environmental Protection Agency Region 7 Spill Hotline
913.281.0991
CDC Hotline 404.639.2540 or 777.488.7100
National Response Center (oil and chemical spills) 800.424.8802
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