Corynebacterium striatum is a non-diphtheritic, gram-positive bacterium, which means it has a specific cell wall structure that stains a certain way during laboratory testing. Under a microscope, it appears as a rod with a “club-like” shape. This bacterium is a facultative anaerobe, indicating it can survive in environments with or without oxygen. While historically not considered a primary cause of disease, its role in human health is being re-evaluated.
From Normal Flora to Opportunistic Pathogen
Corynebacterium striatum is a natural inhabitant of the human body, frequently found on the skin and lining the mucous membranes, such as in the nasal passages and throat. In healthy individuals, it exists as a commensal organism, coexisting peacefully with its human host under typical circumstances. The bacterium’s relationship with humans can shift, transforming it into an opportunistic pathogen. This change occurs when it gains access to parts of the body where it is not normally found or when a person’s immune defenses are lowered. For instance, a break in the skin from a wound can provide a gateway for C. striatum to enter sterile body sites and cause an infection.
Associated Infections and Symptoms
Once Corynebacterium striatum becomes pathogenic, it can cause a wide array of infections. One of the more serious conditions is bacteremia, a bloodstream infection, which can lead to sepsis. General symptoms of bacteremia often include fever and chills. This bacterium is also a recognized cause of respiratory infections, including pneumonia, particularly in individuals with pre-existing lung conditions like chronic obstructive pulmonary disease (COPD). Symptoms of pneumonia typically involve a cough, fever, and difficulty breathing.
Beyond the bloodstream and lungs, C. striatum can infect the heart, leading to endocarditis, an inflammation of the heart’s inner lining and valves. It is also frequently implicated in infections of the musculoskeletal system, such as osteomyelitis (bone infection) and prosthetic joint infections, and can cause skin and soft-tissue infections.
High-Risk Populations and Transmission
Certain groups of people are particularly vulnerable to infections caused by Corynebacterium striatum. Hospitalized patients, especially those in intensive care units (ICUs), are at an elevated risk due to a combination of underlying illnesses and invasive medical procedures. Individuals with compromised immune systems, such as cancer patients undergoing chemotherapy, organ transplant recipients, and the elderly, are also highly susceptible. The presence of indwelling medical devices is a significant risk factor for C. striatum infections.
Catheters, mechanical ventilators, and prosthetic joints can serve as surfaces for the bacteria to colonize and enter the body. For this reason, C. striatum is recognized as a notable cause of healthcare-associated infections. Transmission can occur from person to person through the hands of healthcare workers, and the bacterium’s ability to persist in hospital environments contributes to its spread.
Diagnosis and Treatment Challenges
Diagnosing a Corynebacterium striatum infection typically involves laboratory analysis of clinical samples. A sample of blood, sputum, or tissue from a wound is collected and cultured to grow and identify the bacterium. In the past, this organism was often dismissed as a contaminant from the skin when found in cultures. However, with advanced identification techniques like mass spectrometry and gene sequencing, its role as a true pathogen is now more accurately recognized.
A significant issue in managing these infections is the bacterium’s tendency to be multidrug-resistant (MDR). This means it is often resistant to many different types of antibiotics commonly used to treat gram-positive bacteria, such as penicillins and cephalosporins. This resistance complicates treatment, as standard antibiotic choices may be ineffective. To overcome this, doctors rely on antibiotic susceptibility testing to see which ones are effective. Vancomycin is frequently the antibiotic of choice for serious infections, sometimes used in combination with other drugs.