Shigella

Characteristics
Morphology	Shigella bacteria cause an infection called shigellosis. Shigella spp., of the Enterobacteriaceae family, are gram-negative rod-shaped pathogenic bacteria. They are non-motile, non-encapsulated, and facultative anaerobes that do not ferment lactose, or do so slowly. S. dysenteriae is considered the most virulent, and can produce a potent cytotoxin known as Shigatoxin
Growth Conditions	Shigella strains can be cultivated in Shigella broth (SB), Mueller–Hinton (MH) liquid medium, MacConkey agar, and Columbia agar with 5% sheep blood. Can invade cells in cell culture (i.e. HeLa cells)

Health Hazards
Host Range	Humans and higher primates
Modes of Transmission	Shigella spread easily; it takes just a small number of bacteria to make someone ill. Organisms are spread through the fecal-oral route, and transmission is typically through one of three mechanisms: ingestion of contaminated foods, drinking contaminated water, or by person-to-person contact by anal sexual contact.
Signs and Symptoms	Symptoms of shigellosis include diarrhea (sometimes bloody), fever, nausea, stomach pain, trying to pass a stool when bowels are empty. Some people with shigellosis will not have any symptoms. Post-infectious arthritis, bloodstream infections, seizures, hemolytic-uremic syndrome (HUS) are rare symptoms that can occur from Shigella infections.
Infectious Dose	An infectious dose of 10–100 organisms has been reported
Incubation Period	Ranges from 1 – 7 days; symptoms and shigellosis may occur within 12 – 50 hours.

Medical Precautions/Treatment
Prophylaxis	Hand-washing, strict hygiene control during food preparation, providing safe drinking water, improving toilet facilities and excreta disposal can limit dissemination of the bacteria
Vaccines	None publically available
Treatment	Antibiotic treatment is available, but oral rehydration or electrolyte replacement in dehydrated patients can lead to recovery within days.
Surveillance	Monitor for symptoms. Infection is diagnosed when a laboratory identifies Shigella in the stool of an infected person. The test could be a culture that isolates the bacteria or a rapid diagnostic test that detects genetic material of the bacteria.
GWU Requirements	Report all incidents to the Office of Risk Management as well as the Office of Research Safety (ORS) IMMEDIATELY FOLLOWING THE OCCURRENCE.

Containment
BSL-2/ABSL-2	Risk Group 2 classification is applied to Shigella species. BSL-2 practices, containment equipment, and facilities are recommended for activities using clinical materials and diagnostic quantities of infectious cultures. It is recommended that special emphasis be placed on personal protective equipment, handwashing, manipulation of faucet handles, and decontamination of work surfaces to decrease the risk of LAI. ABSL-2 facilities and practices are recommended for activities with experimentally-infected animals.

Containment

BSL-2/ABSL-2

Risk Group 2 classification is applied to Shigella species. BSL-2 practices, containment equipment, and facilities are recommended for activities using clinical materials and diagnostic quantities of infectious cultures. It is recommended that special emphasis be placed on personal protective equipment, handwashing, manipulation of faucet handles, and decontamination of work surfaces to decrease the risk of LAI. ABSL-2 facilities and practices are recommended for activities with experimentally-infected animals.

Spill Procedures
Small Spills (<1 liter)	If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup. Shigella is not known to be spread via aerosols, but caution should be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against the bacteria (bleach, ethanol, glutaraldehyde), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.
Large Spills	Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Spill Procedures

Small Spills (<1 liter)

If the spill occurred inside a biological safety cabinet, close the sash and allow the cabinet to operate for 15 minutes before continuing with the spill cleanup.

Shigella is not known to be spread via aerosols, but caution should be taken during a spill outside of a BSC. Leave the room immediately and allow the aerosols to dissipate for 15 minutes. Notify others working in the lab. Don appropriate PPE. Cover area of the spill with paper towels or any absorbent material and apply an EPA registered disinfectant effective against the bacteria (bleach, ethanol, glutaraldehyde), working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.

Large Spills

Alert lab personnel in the laboratory to the spill and keep people out of the area to prevent spread of the contamination. Check if you have been contaminated or if any of your PPE has been breached. If so follow exposure procedures. Remove any contaminated clothing and place it the biohazard waste. Wash your hands and post a sign on the door. Notify your supervisor of the incident and call ORS (4-8258) for assistance. If the situation involves an imminently life-threatening injury or has catastrophic potential, call 911.

Exposure Procedures
Mucus Membrane	Flush eyes, mouth or nose for 15 minutes at eyewash station.
Other Exposure	For an area not protected by skin, wash with soap and water for 15 minutes (open wounds, sores, etc.)
Reporting	Report ALL injuries to the PI immediately and reported to the Office of Risk Management at [email protected] IMMEDIATELY FOLLOWING THE OCCURRENCE. Exposures that involve a bloodborne-pathogen or recombinant DNA also need to be reported to the Office of Research Safety at [email protected]. If the injury requires immediate medical attention, call GWPD at 202-994-6111 or call 911.
Medical Monitoring	Seek immediate medical evaluation, treatment, and post exposure follow-up at the Employee Health Office at GWU Hospital (900 23rd St., NW, Suite G-1090, Phone: 202-715-4275). Students should go to the Students Health Office at Marvin Center. After hours treatment can be received at the GWU hospital emergency room.

Stability
Disinfection	Susceptible to 10% bleach, 70% ethanol, 2% glutaraldehyde, iodines, phenolics, and formaldehyde
Inactivation	Organisms can be heat-killed by steaming using an autoclave for 1 hour at 100˚C under normal atmospheric pressure.
Survival Outside Host	Can survive up to months on dry surfaces, up to 10 days in citric juices and carbonated soft drinks, several days on contaminated vegetables, over 3 hours on fingers, 2 – 28 days on metal utensils at 15°C or 0 – 13 days at 37°C, and in feces for 12 days at 25°C.

Personal Protective Equipment (PPE)
Minimum PPE Requirements	At minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with Shigella. Additional PPE may be required depending on lab specific SOPs.
Additional Precautions	Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection. Wash hands with soap and water after removing gloves.

References
CDC (https://www.cdc.gov/shigella/index.html) Canadian PHAC (https://www.canada.ca/en/public-health/services/laboratory-biosafety-bi…) BMBL 6th Edition (https://www.cdc.gov/labs/BMBL.html) How Do the Virulence Factors of Shigella Work Together to Cause Disease (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5364150/ ) ABSA (https://my.absa.org/riskgroups)