Mycobacterium Marinum

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MorphologyGram positive, non-motile, acid-fast, rod-shaped aerobic bacteria with high genomic DNA GC content. Non-pigmented if grown in darkness but bright yellow if grown in light. Smooth to rough colonies on inspissated egg medium and smooth colonies if grown on oleic acid-albumin agar.
Growth ConditionsGrowth on inspissated egg medium or oleic acidalbumin agar at 30°C within 7 or more days

Health Hazards

Host RangeHumans, fish, and other aquatic animals.

Modes of Transmission

Passed from fish to humans through breaks in the skin. This typically occurs when cleaning aquariums or fish tanks, handling or cleaning fish, and swimming or working in fresh or salt-water. M. marinum is not transmissible from human to human.

Signs and Symptoms

Skin lesions or cutaneous granulomas typically near the elbow, knee, foot, finger or toe. More severe forms include tenosynovitis, arthritis, bursitis and osteomyelitis. Disseminated infections are possible but are rare.

Infectious DoseUnknown.
Incubation PeriodSymptoms usually appear within 2 to 4 weeks post inoculation. Some cases have shown symptoms after 2 to 4 months due to the slow-growing nature of the organism.

Medical Precautions/Treatment

ProphylaxisNone available.
VaccinesNone available.
TreatmentResistant to isoniazid but susceptible to ethambutol and rifampin.

Tissue biopsy for culture and histology.

Emory RequirementsReport any exposures.

Laboratory Hazards

SourcesEnvironmental samples, exudates from lesions, and tissues, water used for aquatic animal habitat or growth.

Supplemental References

Canadian MSDSPathogen Safety Data Sheets 
National Center for Biotechnology InformationWelcome to NCBI
Iowa State University- Center for Food Security & Public HealthPiscine Mycobacteriosis (PDF) 


BSL-2When handling clinical materials and cultures.
ABSL-2When conducting animal studies.

Spill Procedures

SmallNotify others working in the lab. Allow aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply an appropriate disinfectant, working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.

Contact Emory’s Biosafety Officer (404-727-8863),
the EHSO Office (404-727-5922), or
The Spill Response Team (404-727-2888).

Exposure Procedures

Mucous membraneFlush eyes, mouth or nose for 15 minutes at eyewash station.
Other ExposuresWash area with soap and water for 15 minutes.
ReportingImmediately report incident to supervisor, complete an employee incident report in PeopleSoft.
Medical Followup 

7am-4pm (OIM): EUH (404-686-7941) EUHM (404-686-7106) WW (404-728-6431)

After Hours: OIM NP On Call 404-686-5500 PIC# 50464

Needle Stick (OIM): EUH (404-686-8587) EUHM (404-686-2352)

Yerkes: Maureen Thompson Office (404-727-8012) Cell (404-275-0963)


DisinfectionGreater resistance to disinfectants and require longer contact times for most disinfectants to be effective; 5% phenol, 1% sodium hypochlorite (low organic matter and longer contact times), iodine solutions (high concentration of available iodine), glutaraldehyde and formaldehyde (longer contact time) are effective.
InactivationSensitive to moist heat (121°C for at least 15 minutes).
Survival Outside HostCarcass and organs (up to 1 year), cereals (3 years), soil (2 years), water (2 years), manure (up to 154 days), saw dust (230 days).

Personal Protective Equipment (PPE)

Minimum PPE RequirementsAt minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with M. marium. Additional PPE may be required depending on lab specific SOPs.
Additional Precautions