Corynebacterium spp.
| Characteristics | |
|---|---|
| Morphology | The genus Corynebacterium comprises a collection of irregular-formed, rod-shaped or coccoid bacteria. They are non-motile and catalase positive. Within the group of medically relevant corynebacteria only a very limited number of Corynebacterium species are potent human pathogens, such as Corynebacterium diphtheriae, the etiological agent of diphtheria. The main virulence factor of this species is diphtheria toxin. Corynebacterium pseudodiphtheriticum is a nonlipophilic, nonfermentive, urease and nitrate-positive Corynebacterium species, which is part of the oropharyngeal bacterial flora. Corynebacterium propinquum and Corynebacterium accolens are Gram-positive bacilli that are known to cause several different kinds of opportunistic infections. |
| Growth Conditions | Part of the natural microbiota of nares and throat, but is cultured on media that contains blood (Brain Heart Infusion Agar or Sheep Blood Agar) at 37oC |
| Health Hazards | |
|---|---|
| Host Range | Humans, but can be isolated from domesticated animals |
| Modes of Transmission | Transmission of C. diphtheriae can occur through droplet nuclei, fomites, and direct contact with cutaneous infections. C. diphtheriae has also been transmitted from hospital wards and clothing. C. pseudodiphtheriticum is associated with opportunistic infections |
| Signs and Symptoms | For C. diphtheriae infections: An upper respiratory tract illness which as pharyngitis or tonsillitis with sore throat, dysphagia, lymphadenitis, low grade fever, malaise, and headache. Cutaneous diphtheria is characterized by formation of lesions on the skin, which may range from a simple pustule to a chronic non-recovering ulcer.
C. pseudodiphtheriticum infection of the respiratory tract causes acute and chronic bronchitis, acute exacerbation of bronchiectasis, pneumonia, and necrotizing tracheitis. Cases of endocarditis, the second most common infection site, urinary tract, and wound infections as well as skin ulcer have been reported.
Both C. propinquum and C. accolens cause a variety of infections ranging from endocarditis, conjunctivitis, keratitis, osteomyelitis, and a handful of respiratory tract infections. |
| Infectious Dose | Varies based on the species |
| Incubation Period | The incubation period is usually 2-4 days after the exposure |
| Medical Precautions/Treatment | |
|---|---|
| Prophylaxis | None readily available |
| Vaccines | Vaccination is available for diphtheria protection, but not for other Corynebacterium species |
| Treatment | Administration of diphtheria antitoxin (DAT) is the most successful treatment for diphtheria. Antibiotic therapy is used to treat most Corynebacterium infections. |
| Surveillance | Monitor for symptoms. Diagnosis of diphtheria is done mainly through monitoring of clinical symptoms. Other methods for identification of these species include: gas-liquid chromatography of cellular fatty acids, and increasingly, the use of 16S rRNA and rpoB gene sequencing |
| 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 these Corynebacterium species. BSL-2 practices, containment equipment, and facilities are recommended for all activities utilizing known or potentially infected clinical materials or cultures. ABSL-2 facilities are recommended for studies utilizing infected laboratory 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.
Corynebacterium species are commonly transmitted via aerosols, 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 | 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, glutaraldehyde, formaldehyde, iodines, hydrogen peroxide, peracetic acid, and quaternary ammonium compounds |
| Inactivation | Most vegetative bacteria can be inactivated by moist heat (121°C for 15 min- 30 min) and dry heat (160-170°C for 1-2 hours) |
| Survival Outside Host | C. diphtheriae can survive on dry inanimate surfaces from 7 days to 6 months. Other species do not have well characterized survival data, but are assumed to have stability in a multitude of environments due to being a part of human flora. |
| 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 Corynebacterium species. 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 | |
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