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Biological Hazards in Medical

and Research Laboratories

October, 2010


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This module gives an overview of how bacteria and virusescan cause injury, illness, or even death to medical laboratory

workers.

What You Will Learn


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Bacteria Exposure

The Centers for Disease Control (CDC)data indicates these bacteria have a high

exposure potential in labs:

Mycobacterium tuberculosis Bacillus anthracis

Bordetella pertussis

Brucella sp. Neisseria meningitis

Many labs also culture other types of dangerous bacteria.


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Bacteria Exposure

In the lab bacteria can become airborne by:

Removing vacutainer caps

Manipulation of cultures

Centrifuge, test tube fractures/cracks


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Bacteria Exposure - Tuberculosis

Present in sputum, gastric fluid, CSF, urine and

lesions of persons with active disease (not latent)

Bacilli survive in heat-fixed smears

Transmitted via airborne droplet from an infected

persons respiration, in preparation of frozen sections

and in preparation of liquid cultures.


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Tuberculosis

90% of all persons infected with TB will never develop active TB

TB infected or exposed people are NOT contagious

Only contagious if they have ACTIVE TB disease

Source: CDC

- Surveillance: PPD skin testing or blood assay based on laboratorys risk

level.

- Prior vaccination with BCG not considered when interpreting PPD skin test.It is impossible to differentiate between BCG mediated response and latent

infection.


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Bacteria Exposure - Anthrax

Present in blood, skin lesion exudate,CSF, pleural fluid, rarely in urine and

feces

Aerosolized during handling

Direct and indirect contact of intact or

broken skin with cultures and

contaminated lab surfaces

- Requires prompt diagnosis- Vaccine is available

Gram-positive anthrax

bacteria (purple rods) in

cerebrospinal fluid sample
http://en.wikipedia.org/wiki/File:Gram_Stain_Anthrax.jpg


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An Anthrax Infection Incident

Lab in Texas was processing environmental samples

for anthrax in support of CDC bioterrorism

investigation.

A worker had cut his face shaving. The next day, he

was moving vials containing aliquots of confirmed

anthrax from the biological safety cabinet to a freezer

in the next room. The worker did not use gloves. He

washed his hands after handling the vials.

Within one day, his facial cut worsened on day 5, he

was admitted to the hospital and treated for cutaneous

anthrax.

Most likely source was the surface of the vials. No workers in the lab were immunized against anthrax.

From April 5, 2002 MMWR (Morbidity and Mortality Weekly Report from CDC)

Skin anthrax-source: CDC


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Pertussis (whooping cough):

Hazard is aerosol generation during

culture manipulation

Incidence on the rise see the latest

report

May be mild or classic in adults

Most lab cases in research labs

Source: CDC

- A pertussis vaccine is now

available for adults
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5926a5.htm?s_cid=mm5926a5_e%0d%0ahttp://www.cdc.gov/mmwr/preview/mmwrhtml/mm5926a5.htm?s_cid=mm5926a5_e%0d%0ahttp://www.cdc.gov/mmwr/preview/mmwrhtml/rr5517a1.htmhttp://www.cdc.gov/mmwr/preview/mmwrhtml/rr5517a1.htmhttp://www.cdc.gov/mmwr/preview/mmwrhtml/mm5926a5.htm?s_cid=mm5926a5_e%0d%0ahttp://www.cdc.gov/mmwr/preview/mmwrhtml/mm5926a5.htm?s_cid=mm5926a5_e%0d%0a


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Brucellosis

One of the most commonly

reported lab-associatedbacterial infection

Present in blood, CSF, semen

and occasionally urine ofinfected persons

Transmitted through aerosols

generating procedures

- No vaccine for humans,treatment is with antibiotics

Reported cases of brucellosis - 2007

Source: CDC

CDC recommendations for brucellosis lab exposure
http://www.azdhs.gov/phs/oids/vector/brucella/pdf/CDC%20RECOMMENDATIONS%20FOR%20BRUCELLA%20LABORATORY%20EXPOSURES.pdfhttp://www.azdhs.gov/phs/oids/vector/brucella/pdf/CDC%20RECOMMENDATIONS%20FOR%20BRUCELLA%20LABORATORY%20EXPOSURES.pdf


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N. Meningitis

Present in pharyngeal exudates,

synovial fluid, urine, feces, CSF

Aerosols from laboratory procedures

on isolates

Vaccine is available andrecommended for lab workers

routinely exposed.

Post-exposure antibiotics

o Rifampin or ciprofloxacin given orally; or

o Ceftriaxone given IM

The use of post-exposure antibiotics have prevented outbreaks.

Link to CDC webpage on meningitis

N. Meningitis bacteria
http://www.cdc.gov/meningitis/index.htmlhttp://www.cdc.gov/meningitis/index.html


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Meningitis Exposure Incidents

Two microbiologists contracted meningitis, both died.

#1: 3 days before symptoms, the patient had prepared a gram stain

from the blood culture of a patient who was subsequently shown to

have meningococcal disease. The microbiologist had also handledand sub-cultured agar plates w/ CSF. At this lab, aspiration from

blood culture bottles was performed at an open lab bench.

#2: Microbiologist who worked at state public health lab and

worked on several n meningitides isolates performed slide

agglutination tests. Used BioSafety Level 2 precautions.

In 15 years, there were 16 cases of meningitis in lab personnel, of

which 50% were fatal.

From MMWR 2/22/02


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Other Possible Pathogen Exposures

Fungal agents:

Coccidioimycosis and Histoplasmosis

Hazard because spores are


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Other Possible Pathogen Exposure

Parasitic agents:

Intestinal (giardia, toxoplasmosis), tissue and

organs (trichinosis), blood (malaria)

Ingestion is primary hazard

Also can enter body through breaks in the skin

CDC webpage on parasitic diseases

CDC webpage in giardia
http://www.cdc.gov/ncidod/dpd/http://www.cdc.gov/ncidod/dpd/parasites/giardiasis/moreinfo_giardiasis.htmhttp://www.cdc.gov/ncidod/dpd/parasites/giardiasis/moreinfo_giardiasis.htmhttp://www.cdc.gov/ncidod/dpd/


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Other Possible Pathogen Exposure

Prions:

Transmissible spongiform encephalopathies Present in CNS of animals

Resistant to conventional inactivation

No known treatment

Includes Creutzfeldt-Jakob disease

Link to CDC Prion Diseases webpage

This tissue slide shows sponge-like lesions in the

brain tissue of a classic CJD patient. This lesion

is typical of many prion diseases.
http://www.cdc.gov/ncidod/dvrd/prions/index.htmhttp://www.cdc.gov/ncidod/dvrd/prions/index.htm


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Other Possible Pathogen Exposures

Rickettsial Agents: Coxiella burnetti Q fever

o High risk of lab infection

oAerosol and parenteral exposures

Rickettsia species

o Typhus, reported in 57 lab-associated cases

o Rocky mountain spotted fever, in 1976, 63 lab

cases were reported, 11 were fataloAerosols and parenteral inoculation

CDC webpage on Q Fever CDC webpage on Rickettsia
http://www.cdc.gov/ncidod/dvrd/qfever/index.htmhttp://www.cdc.gov/ticks/diseases/other_spotted_fevers/http://www.cdc.gov/ticks/diseases/other_spotted_fevers/http://www.cdc.gov/ncidod/dvrd/qfever/index.htm


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Virus Exposure

Some viruses are transmitted via aerosols

such as: Hantavirus lab infections have occurred

during rodent handling

Human herpes viruses Influenza

Various pox viruses

Herpes viruses are ubiquitous primarily an opportunistic infection. Rarely,

cytomegalovirus or Epstein-Barr may be transmitted in the lab. No documentation

that influenza has been contracted in the lab as it also is ubiquitous in season.

CDC lab management of agents associated with hantavirus

interim biosafety guidelines -1994
http://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdfhttp://www.cdc.gov/mmwr/PDF/rr/rr4307.pdf


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Virus Exposure Blood/Body Fluids

Some pathogens are transmitted through

microorganisms contained in blood and other

body fluids.

Examples are:

Hepatitis B Virus (HBV)

Hepatitis C Virus (HCV)

Hepatitis D Virus (HDV)

Human Immunodeficiency Virus (HIV)

Link to Exposure to Blood brochure
http://www.cdc.gov/ncidod/dhqp/pdf/bbp/Exp_to_Blood.pdfhttp://www.cdc.gov/ncidod/dhqp/pdf/bbp/Exp_to_Blood.pdf


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Blood includes:

Human blood

Human blood components, such as

packed cells and plasma

Products made from human blood, such

as:

Clotting agents for hemophilia

Immune globulins including Rh factor immune

globulins


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Potentially infectious body fluids include:


Semen

Vaginal secretions

Cerebrospinal fluid

Synovial fluid

Pleural fluid

Pericardial fluid

Peritoneal fluid

Amniotic fluid

Saliva in dental

procedures


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Other pathogens that can also be transmitted

through blood include:

Malaria

Syphilis

Brucellosis

Leptospirosis

Cruetzfeldt-Jakob Disease

Some fungi and ricketsii


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Virus Exposure

Hepatitis A and E:

Fecally transmitted

We hear about it in the news when infected

restaurant workers may expose a community

Although high virus titers may be present in blood

during the incubation period, lab transmission notreported

Hepatitis A virus


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Hepatitis B, C, and D

Transmitted via blood or other body

fluids

Causes liver inflammation and/or

damage - mild to fatal

Can live in a dry environment > 7 days,

such as on countertop

Highest risk of transmission through

hollow bore needle stick

Healthy human liver

Hepatitis C liver

Copyright1998

TrusteesofDartmouthC

ollege
http://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.htmlhttp://www.epidemic.org/rightsReserved.html


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Hepatitis B, C, and D

Hepatitis B, active and passive vaccines available

Hepatitis C, no vaccine available

Hepatitis D, no vaccine available, however

immunization against hepatitis B also protects

against hepatitis D


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Human Immunodeficiency Virus (HIV) Attacks the human immune system

Can live in a dry environment for only

a few hours

No vaccine available

Antiviral post-exposure prophylaxis

effective in reducing risk

Reference: MMWR June 29, 2001/50(RR11);1-42

HIV - seen as smallspheres on the surfaceof white blood cells


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HIV Virus Exposure Routes

Parenteral Needlestick

Scalpel/glass cut

Mucous membrane

Mouth pipetting

Eating, drinking in lab area

Not wearing appropriate PPE

Non-intact skino Unguarded splash

o Contact with contaminated surfaces

o Not covering skin breaks


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HIV Virus Exposure

Occupationally acquired HIV :The CDC reports as of December 2001, 51 of the 57 cases

of occupationally acquired HIV infection involved sharps

injuries of which nearly half involved needles used in

phlebotomy or blood sampling from a vascular line, withvacuum- tube device needles accounting for the largest

number of these injuries.

Other sharps injuries included broken glass from blood

collection tubes and a needle for cleaning/dislodging debrisin laboratory equipment.

Reference: Surveillance of Occupationally Acquired

HIV/AIDS in Healthcare Personnel December, 2006
http://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.htmlhttp://www.cdc.gov/ncidod/dhqp/bp_hcp_w_hiv.html


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Lab Practices & Biosafety Guidelines

The Centers for Disease Control (CDC) hasguidelines to describe combinations of:

Laboratory Practices and Techniques

o Standard Practiceso Special Practices

Safety Equipment

Laboratory Facilities

CDC Laboratory Guidelines and Standards webpage

CDC Biosafety Webpage includes a biosecurity online training course
http://wwwn.cdc.gov/dls/guidstd.aspxhttp://www.cdc.gov/biosafety/http://www.cdc.gov/biosafety/http://wwwn.cdc.gov/dls/guidstd.aspx


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CDC Biosafety Guidelines

These guidelines are called:

Biosafety in Medical and Biomedical Laboratories(BMBL - 5th edition)*

The guidelines describe four laboratory hazard

levels or Biosafety Levels (BSL)

* Someof the information in this module is derived from this document
http://www.cdc.gov/biosafety/publications/bmbl5/index.htmhttp://www.cdc.gov/biosafety/publications/bmbl5/index.htmhttp://www.cdc.gov/biosafety/publications/bmbl5/index.htm


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Biosafety Guidelines

Biosafety Levels 1- 4 provide:

Increasing levels of personnel and

environmental protection

Guidelines for working safely in

microbiological and biomedicallaboratories

Class I Biosafety Cabinet(from CDC publicationSelection,

Installation & Use of Biosafety Cabinets)
http://www.cdc.gov/biosafety/publications/bmbl5/BMBL5_appendixA.pdfhttp://www.cdc.gov/biosafety/publications/bmbl5/BMBL5_appendixA.pdfhttp://www.cdc.gov/biosafety/publications/bmbl5/BMBL5_appendixA.pdfhttp://www.cdc.gov/biosafety/publications/bmbl5/BMBL5_appendixA.pdf


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Biosafety Levels (BSL)

The Four Biosafety Levels are:

BSL1 - agents not known to cause disease (B. subtilis, E. coli).

BSL2 - agents associated with human disease (hepatitis B,

Salmonellae, Toxoplasma)

BSL3 - indigenous/exotic agents associated with human disease

and with potential for aerosol transmission (M. tuberculosis, C.

burnetii).

BSL4 - dangerous/exotic agents of life threatening nature(Marbug and Ebola virus).


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DOSH Rules related to biological hazards

Occupational Exposure to BloodbornePathogensWAC 296-823

This rule provides requirements to protect

employees from exposure to blood or otherpotentially infectious materials, that may

contain bloodborne pathogens.

The rule covers anticipated exposure, even

if no actual incidents have occurred.

Link to Online Training course on Bloodborne Pathogens
http://www.lni.wa.gov/wisha/rules/bbpathogens/default.htmhttp://www.lni.wa.gov/Safety/TrainTools/Online/Courses/default.asp?P_ID=200http://www.lni.wa.gov/Safety/TrainTools/Online/Courses/default.asp?P_ID=200http://www.lni.wa.gov/wisha/rules/bbpathogens/default.htmhttp://www.lni.wa.gov/wisha/rules/bbpathogens/default.htmhttp://www.lni.wa.gov/wisha/rules/bbpathogens/default.htm


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Other Related DOSH Rules & Directives

Protect Employees from BiologicalAgents 296-800-11045 refers toCDC guidelines

Personal Protective Equipment,

296-800-160

Tuberculosis - WRD 11.35
http://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/Safety/Rules/Policies/PDFs/WRD1135.pdfhttp://www.lni.wa.gov/Safety/Rules/Policies/PDFs/WRD1135.pdfhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-160.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htmhttp://www.lni.wa.gov/wisha/rules/corerules/HTML/296-800-110.htm

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